操作系统开发

开发平台：

WINDOWS

BOOK.T：源码内容

17234 rmp->mp_effuid = s_buf.st_uid;
17235 tell_fs(SETUID,who, (int)rmp->mp_realuid, (int)rmp->mp_effuid);
17236 }
17237 if (s_buf.st_mode & I_SET_GID_BIT) {
17238 rmp->mp_effgid = s_buf.st_gid;
17239 tell_fs(SETGID,who, (int)rmp->mp_realgid, (int)rmp->mp_effgid);
17240 }
17241 }
17242
17243 /* Save offset to initial argc (for ps) */
17244 rmp->mp_procargs = vsp;
17245
17246 /* Fix 'mproc' fields, tell kernel that exec is done, reset caught sigs. */
17247 for (sn = 1; sn <= _NSIG; sn++) {
17248 if (sigismember(&rmp->mp_catch, sn)) {
17249 sigdelset(&rmp->mp_catch, sn);
17250 rmp->mp_sigact[sn].sa_handler = SIG_DFL;
17251 sigemptyset(&rmp->mp_sigact[sn].sa_mask);
17252 }
17253 }
17254
17255 rmp->mp_flags &= ~SEPARATE; /* turn off SEPARATE bit */
17256 rmp->mp_flags |= ft; /* turn it on for separate I & D files */
17257 new_sp = (char *) vsp;
17258
17259 tell_fs(EXEC, who, 0, 0); /* allow FS to handle FD_CLOEXEC files */
.Op 239 src/mm/exec.c
17260
17261 /* System will save command line for debugging, ps(1) output, etc. */
17262 basename = strrchr(name_buf, '/');
17263 if (basename == NULL) basename = name_buf; else basename++;
17264 sys_exec(who, new_sp, rmp->mp_flags & TRACED, basename, pc);
17265 return(OK);
17266 }
17269 /*===========================================================================*
17270 * read_header *
17271 *===========================================================================*/
17272 PRIVATE int read_header(fd, ft, text_bytes, data_bytes, bss_bytes,
17273 tot_bytes, sym_bytes, sc, pc)
17274 int fd; /* file descriptor for reading exec file */
17275 int *ft; /* place to return ft number */
17276 vir_bytes *text_bytes; /* place to return text size */
17277 vir_bytes *data_bytes; /* place to return initialized data size */
17278 vir_bytes *bss_bytes; /* place to return bss size */
17279 phys_bytes *tot_bytes; /* place to return total size */
17280 long *sym_bytes; /* place to return symbol table size */
17281 vir_clicks sc; /* stack size in clicks */
17282 vir_bytes *pc; /* program entry point (initial PC) */
17283 {
17284 /* Read the header and extract the text, data, bss and total sizes from it. */
17285
17286 int m, ct;
17287 vir_clicks tc, dc, s_vir, dvir;
17288 phys_clicks totc;
17289 struct exec hdr; /* a.out header is read in here */
17290
17291 /* Read the header and check the magic number. The standard MINIX header
17292 * is defined in <a.out.h>. It consists of 8 chars followed by 6 longs.
17293 * Then come 4 more longs that are not used here.
17294 * Byte 0: magic number 0x01
17295 * Byte 1: magic number 0x03
17296 * Byte 2: normal = 0x10 (not checked, 0 is OK), separate I/D = 0x20
17297 * Byte 3: CPU type, Intel 16 bit = 0x04, Intel 32 bit = 0x10,
17298 * Motorola = 0x0B, Sun SPARC = 0x17
17299 * Byte 4: Header length = 0x20
17300 * Bytes 5-7 are not used.
17301 *
17302 * Now come the 6 longs
17303 * Bytes 8-11: size of text segments in bytes
17304 * Bytes 12-15: size of initialized data segment in bytes
17305 * Bytes 16-19: size of bss in bytes
17306 * Bytes 20-23: program entry point
17307 * Bytes 24-27: total memory allocated to program (text, data + stack)
17308 * Bytes 28-31: size of symbol table in bytes
17309 * The longs are represented in a machine dependent order,
17310 * little-endian on the 8088, big-endian on the 68000.
17311 * The header is followed directly by the text and data segments, and the
17312 * symbol table (if any). The sizes are given in the header. Only the
17313 * text and data segments are copied into memory by exec. The header is
17314 * used here only. The symbol table is for the benefit of a debugger and
17315 * is ignored here.
17316 */
17317
17318 if (read(fd, (char *) &hdr, A_MINHDR) != A_MINHDR) return(ENOEXEC);
17319
.Ep 240 src/mm/exec.c
17320 /* Check magic number, cpu type, and flags. */
17321 if (BADMAG(hdr)) return(ENOEXEC);
17322 #if (CHIP == INTEL && _WORD_SIZE == 2)
17323 if (hdr.a_cpu != A_I8086) return(ENOEXEC);
17324 #endif
17325 #if (CHIP == INTEL && _WORD_SIZE == 4)
17326 if (hdr.a_cpu != A_I80386) return(ENOEXEC);
17327 #endif
17328 if ((hdr.a_flags & ~(A_NSYM | A_EXEC | A_SEP)) != 0) return(ENOEXEC);
17329
17330 *ft = ( (hdr.a_flags & A_SEP) ? SEPARATE : 0); /* separate I & D or not */
17331
17332 /* Get text and data sizes. */
17333 *text_bytes = (vir_bytes) hdr.a_text; /* text size in bytes */
17334 *data_bytes = (vir_bytes) hdr.a_data; /* data size in bytes */
17335 *bss_bytes = (vir_bytes) hdr.a_bss; /* bss size in bytes */
17336 *tot_bytes = hdr.a_total; /* total bytes to allocate for prog */
17337 *sym_bytes = hdr.a_syms; /* symbol table size in bytes */
17338 if (*tot_bytes == 0) return(ENOEXEC);
17339
17340 if (*ft != SEPARATE) {
17341
17342 /* If I & D space is not separated, it is all considered data. Text=0*/
17343 *data_bytes += *text_bytes;
17344 *text_bytes = 0;
17345
17346 }
17347 *pc = hdr.a_entry; /* initial address to start execution */
17348
17349 /* Check to see if segment sizes are feasible. */
17350 tc = ((unsigned long) *text_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17351 dc = (*data_bytes + *bss_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17352 totc = (*tot_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17353 if (dc >= totc) return(ENOEXEC); /* stack must be at least 1 click */
17354 dvir = (*ft == SEPARATE ? 0 : tc);
17355 s_vir = dvir + (totc - sc);
17356 m = size_ok(*ft, tc, dc, sc, dvir, s_vir);
17357 ct = hdr.a_hdrlen & BYTE; /* header length */
17358 if (ct > A_MINHDR) lseek(fd, (off_t) ct, SEEK_SET); /* skip unused hdr */
17359 return(m);
17360 }
17363 /*===========================================================================*
17364 * new_mem *
17365 *===========================================================================*/
17366 PRIVATE int new_mem(sh_mp, text_bytes, data_bytes,bss_bytes,stk_bytes,tot_bytes)
17367 struct mproc *sh_mp; /* text can be shared with this process */
17368 vir_bytes text_bytes; /* text segment size in bytes */
17369 vir_bytes data_bytes; /* size of initialized data in bytes */
17370 vir_bytes bss_bytes; /* size of bss in bytes */
17371 vir_bytes stk_bytes; /* size of initial stack segment in bytes */
17372 phys_bytes tot_bytes; /* total memory to allocate, including gap */
17373 {
17374 /* Allocate new memory and release the old memory. Change the map and report
17375 * the new map to the kernel. Zero the new core image's bss, gap and stack.
17376 */
17377
17378 register struct mproc *rmp;
17379 vir_clicks text_clicks, data_clicks, gap_clicks, stack_clicks, tot_clicks;
.Op 241 src/mm/exec.c
17380 phys_clicks new_base;
17381
17382 static char zero[1024]; /* used to zero bss */
17383 phys_bytes bytes, base, count, bss_offset;
17384
17385 /* No need to allocate text if it can be shared. */
17386 if (sh_mp != NULL) text_bytes = 0;
17387
17388 /* Acquire the new memory. Each of the 4 parts: text, (data+bss), gap,
17389 * and stack occupies an integral number of clicks, starting at click
17390 * boundary. The data and bss parts are run together with no space.
17391 */
17392
17393 text_clicks = ((unsigned long) text_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17394 data_clicks = (data_bytes + bss_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17395 stack_clicks = (stk_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17396 tot_clicks = (tot_bytes + CLICK_SIZE - 1) >> CLICK_SHIFT;
17397 gap_clicks = tot_clicks - data_clicks - stack_clicks;
17398 if ( (int) gap_clicks < 0) return(ENOMEM);
17399
17400 /* Check to see if there is a hole big enough. If so, we can risk first
17401 * releasing the old core image before allocating the new one, since we
17402 * know it will succeed. If there is not enough, return failure.
17403 */
17404 if (text_clicks + tot_clicks > max_hole()) return(EAGAIN);
17405
17406 /* There is enough memory for the new core image. Release the old one. */
17407 rmp = mp;
17408
17409 if (find_share(rmp, rmp->mp_ino, rmp->mp_dev, rmp->mp_ctime) == NULL) {
17410 /* No other process shares the text segment, so free it. */
17411 free_mem(rmp->mp_seg[T].mem_phys, rmp->mp_seg[T].mem_len);
17412 }
17413 /* Free the data and stack segments. */
17414 free_mem(rmp->mp_seg[D].mem_phys,
17415 rmp->mp_seg[S].mem_vir + rmp->mp_seg[S].mem_len - rmp->mp_seg[D].mem_vir);
17416
17417 /* We have now passed the point of no return. The old core image has been
17418 * forever lost. The call must go through now. Set up and report new map.
17419 */
17420 new_base = alloc_mem(text_clicks + tot_clicks); /* new core image */
17421 if (new_base == NO_MEM) panic("MM hole list is inconsistent", NO_NUM);
17422
17423 if (sh_mp != NULL) {
17424 /* Share the text segment. */
17425 rmp->mp_seg[T] = sh_mp->mp_seg[T];
17426 } else {
17427 rmp->mp_seg[T].mem_phys = new_base;
17428 rmp->mp_seg[T].mem_vir = 0;
17429 rmp->mp_seg[T].mem_len = text_clicks;
17430 }
17431 rmp->mp_seg[D].mem_phys = new_base + text_clicks;
17432 rmp->mp_seg[D].mem_vir = 0;
17433 rmp->mp_seg[D].mem_len = data_clicks;
17434 rmp->mp_seg[S].mem_phys = rmp->mp_seg[D].mem_phys + data_clicks + gap_clicks;
17435 rmp->mp_seg[S].mem_vir = rmp->mp_seg[D].mem_vir + data_clicks + gap_clicks;
17436 rmp->mp_seg[S].mem_len = stack_clicks;
17437
17438
17439 sys_newmap(who, rmp->mp_seg); /* report new map to the kernel */
.Ep 242 src/mm/exec.c
17440
17441 /* Zero the bss, gap, and stack segment. */
17442 bytes = (phys_bytes)(data_clicks + gap_clicks + stack_clicks) << CLICK_SHIFT;
17443 base = (phys_bytes) rmp->mp_seg[D].mem_phys << CLICK_SHIFT;
17444 bss_offset = (data_bytes >> CLICK_SHIFT) << CLICK_SHIFT;
17445 base += bss_offset;
17446 bytes -= bss_offset;
17447
17448 while (bytes > 0) {
17449 count = MIN(bytes, (phys_bytes) sizeof(zero));
17450 if (sys_copy(MM_PROC_NR, D, (phys_bytes) zero,
17451 ABS, 0, base, count) != OK) {
17452 panic("new_mem can't zero", NO_NUM);
17453 }
17454 base += count;
17455 bytes -= count;
17456 }
17457
17458 return(OK);
17459 }
17462 /*===========================================================================*
17463 * patch_ptr *
17464 *===========================================================================*/
17465 PRIVATE void patch_ptr(stack, base)
17466 char stack[ARG_MAX]; /* pointer to stack image within MM */
17467 vir_bytes base; /* virtual address of stack base inside user */
17468 {
17469 /* When doing an exec(name, argv, envp) call, the user builds up a stack
17470 * image with arg and env pointers relative to the start of the stack. Now
17471 * these pointers must be relocated, since the stack is not positioned at
17472 * address 0 in the user's address space.
17473 */
17474
17475 char **ap, flag;
17476 vir_bytes v;
17477
17478 flag = 0; /* counts number of 0-pointers seen */
17479 ap = (char **) stack; /* points initially to 'nargs' */
17480 ap++; /* now points to argv[0] */
17481 while (flag < 2) {
17482 if (ap >= (char **) &stack[ARG_MAX]) return; /* too bad */
17483 if (*ap != NIL_PTR) {
17484 v = (vir_bytes) *ap; /* v is relative pointer */
17485 v += base; /* relocate it */
17486 *ap = (char *) v; /* put it back */
17487 } else {
17488 flag++;
17489 }
17490 ap++;
17491 }
17492 }
17495 /*===========================================================================*
17496 * load_seg *
17497 *===========================================================================*/
17498 PRIVATE void load_seg(fd, seg, seg_bytes)
17499 int fd; /* file descriptor to read from */
.Op 243 src/mm/exec.c
17500 int seg; /* T or D */
17501 vir_bytes seg_bytes; /* how big is the segment */
17502 {
17503 /* Read in text or data from the exec file and copy to the new core image.
17504 * This procedure is a little bit tricky. The logical way to load a segment
17505 * would be to read it block by block and copy each block to the user space
17506 * one at a time. This is too slow, so we do something dirty here, namely
17507 * send the user space and virtual address to the file system in the upper
17508 * 10 bits of the file descriptor, and pass it the user virtual address
17509 * instead of a MM address. The file system extracts these parameters when
17510 * gets a read call from the memory manager, which is the only process that
17511 * is permitted to use this trick. The file system then copies the whole
17512 * segment directly to user space, bypassing MM completely.
17513 */
17514
17515 int new_fd, bytes;
17516 char *ubuf_ptr;
17517
17518 new_fd = (who << 8) | (seg << 6) | fd;
17519 ubuf_ptr = (char *) ((vir_bytes)mp->mp_seg[seg].mem_vir << CLICK_SHIFT);
17520 while (seg_bytes != 0) {
17521 bytes = (INT_MAX / BLOCK_SIZE) * BLOCK_SIZE;
17522 if (seg_bytes < bytes)
17523 bytes = (int)seg_bytes;
17524 if (read(new_fd, ubuf_ptr, bytes) != bytes)
17525 break; /* error */
17526 ubuf_ptr += bytes;
17527 seg_bytes -= bytes;
17528 }
17529 }
17532 /*===========================================================================*
17533 * find_share *
17534 *===========================================================================*/
17535 PUBLIC struct mproc *find_share(mp_ign, ino, dev, ctime)
17536 struct mproc *mp_ign; /* process that should not be looked at */
17537 ino_t ino; /* parameters that uniquely identify a file */
17538 dev_t dev;
17539 time_t ctime;
17540 {
17541 /* Look for a process that is the file <ino, dev, ctime> in execution. Don't
17542 * accidentally "find" mp_ign, because it is the process on whose behalf this
17543 * call is made.
17544 */
17545 struct mproc *sh_mp;
17546
17547 for (sh_mp = &mproc[INIT_PROC_NR]; sh_mp < &mproc[NR_PROCS]; sh_mp++) {
17548 if ((sh_mp->mp_flags & (IN_USE | HANGING | SEPARATE))
17549 != (IN_USE | SEPARATE)) continue;
17550 if (sh_mp == mp_ign) continue;
17551 if (sh_mp->mp_ino != ino) continue;
17552 if (sh_mp->mp_dev != dev) continue;
17553 if (sh_mp->mp_ctime != ctime) continue;
17554 return sh_mp;
17555 }
17556 return(NULL);
17557 }
.Ep 244 src/mm/break.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/break.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
17600 /* The MINIX model of memory allocation reserves a fixed amount of memory for
17601 * the combined text, data, and stack segments. The amount used for a child
17602 * process created by FORK is the same as the parent had. If the child does
17603 * an EXEC later, the new size is taken from the header of the file EXEC'ed.
17604 *
17605 * The layout in memory consists of the text segment, followed by the data
17606 * segment, followed by a gap (unused memory), followed by the stack segment.
17607 * The data segment grows upward and the stack grows downward, so each can
17608 * take memory from the gap. If they meet, the process must be killed. The
17609 * procedures in this file deal with the growth of the data and stack segments.
17610 *
17611 * The entry points into this file are:
17612 * do_brk: BRK/SBRK system calls to grow or shrink the data segment
17613 * adjust: see if a proposed segment adjustment is allowed
17614 * size_ok: see if the segment sizes are feasible
17615 */
17616
17617 #include "mm.h"
17618 #include <signal.h>
17619 #include "mproc.h"
17620 #include "param.h"
17621
17622 #define DATA_CHANGED 1 /* flag value when data segment size changed */
17623 #define STACK_CHANGED 2 /* flag value when stack size changed */
17624
17625 /*===========================================================================*
17626 * do_brk *
17627 *===========================================================================*/
17628 PUBLIC int do_brk()
17629 {
17630 /* Perform the brk(addr) system call.
17631 *
17632 * The call is complicated by the fact that on some machines (e.g., 8088),
17633 * the stack pointer can grow beyond the base of the stack segment without
17634 * anybody noticing it.
17635 * The parameter, 'addr' is the new virtual address in D space.
17636 */
17637
17638 register struct mproc *rmp;
17639 int r;
17640 vir_bytes v, new_sp;
17641 vir_clicks new_clicks;
17642
17643 rmp = mp;
17644 v = (vir_bytes) addr;
17645 new_clicks = (vir_clicks) ( ((long) v + CLICK_SIZE - 1) >> CLICK_SHIFT);
17646 if (new_clicks < rmp->mp_seg[D].mem_vir) {
17647 res_ptr = (char *) -1;
17648 return(ENOMEM);
17649 }
17650 new_clicks -= rmp->mp_seg[D].mem_vir;
17651 sys_getsp(who, &new_sp); /* ask kernel for current sp value */
17652 r = adjust(rmp, new_clicks, new_sp);
17653 res_ptr = (r == OK ? addr : (char *) -1);
17654 return(r); /* return new address or -1 */
.Op 245 src/mm/break.c
17655 }
17658 /*===========================================================================*
17659 * adjust *
17660 *===========================================================================*/
17661 PUBLIC int adjust(rmp, data_clicks, sp)
17662 register struct mproc *rmp; /* whose memory is being adjusted? */
17663 vir_clicks data_clicks; /* how big is data segment to become? */
17664 vir_bytes sp; /* new value of sp */
17665 {
17666 /* See if data and stack segments can coexist, adjusting them if need be.
17667 * Memory is never allocated or freed. Instead it is added or removed from the
17668 * gap between data segment and stack segment. If the gap size becomes
17669 * negative, the adjustment of data or stack fails and ENOMEM is returned.
17670 */
17671
17672 register struct mem_map *mem_sp, *mem_dp;
17673 vir_clicks sp_click, gap_base, lower, old_clicks;
17674 int changed, r, ft;
17675 long base_of_stack, delta; /* longs avoid certain problems */
17676
17677 mem_dp = &rmp->mp_seg[D]; /* pointer to data segment map */
17678 mem_sp = &rmp->mp_seg[S]; /* pointer to stack segment map */
17679 changed = 0; /* set when either segment changed */
17680
17681 if (mem_sp->mem_len == 0) return(OK); /* don't bother init */
17682
17683 /* See if stack size has gone negative (i.e., sp too close to 0xFFFF...) */
17684 base_of_stack = (long) mem_sp->mem_vir + (long) mem_sp->mem_len;
17685 sp_click = sp >> CLICK_SHIFT; /* click containing sp */
17686 if (sp_click >= base_of_stack) return(ENOMEM); /* sp too high */
17687
17688 /* Compute size of gap between stack and data segments. */
17689 delta = (long) mem_sp->mem_vir - (long) sp_click;
17690 lower = (delta > 0 ? sp_click : mem_sp->mem_vir);
17691
17692 /* Add a safety margin for future stack growth. Impossible to do right. */
17693 #define SAFETY_BYTES (384 * sizeof(char *))
17694 #define SAFETY_CLICKS ((SAFETY_BYTES + CLICK_SIZE - 1) / CLICK_SIZE)
17695 gap_base = mem_dp->mem_vir + data_clicks + SAFETY_CLICKS;
17696 if (lower < gap_base) return(ENOMEM); /* data and stack collided */
17697
17698 /* Update data length (but not data orgin) on behalf of brk() system call. */
17699 old_clicks = mem_dp->mem_len;
17700 if (data_clicks != mem_dp->mem_len) {
17701 mem_dp->mem_len = data_clicks;
17702 changed |= DATA_CHANGED;
17703 }
17704
17705 /* Update stack length and origin due to change in stack pointer. */
17706 if (delta > 0) {
17707 mem_sp->mem_vir -= delta;
17708 mem_sp->mem_phys -= delta;
17709 mem_sp->mem_len += delta;
17710 changed |= STACK_CHANGED;
17711 }
17712
17713 /* Do the new data and stack segment sizes fit in the address space? */
17714 ft = (rmp->mp_flags & SEPARATE);
.Ep 246 src/mm/break.c
17715 r = size_ok(ft, rmp->mp_seg[T].mem_len, rmp->mp_seg[D].mem_len,
17716 rmp->mp_seg[S].mem_len, rmp->mp_seg[D].mem_vir, rmp->mp_seg[S].mem_vir);
17717 if (r == OK) {
17718 if (changed) sys_newmap((int)(rmp - mproc), rmp->mp_seg);
17719 return(OK);
17720 }
17721
17722 /* New sizes don't fit or require too many page/segment registers. Restore.*/
17723 if (changed & DATA_CHANGED) mem_dp->mem_len = old_clicks;
17724 if (changed & STACK_CHANGED) {
17725 mem_sp->mem_vir += delta;
17726 mem_sp->mem_phys += delta;
17727 mem_sp->mem_len -= delta;
17728 }
17729 return(ENOMEM);
17730 }
17733 /*===========================================================================*
17734 * size_ok *
17735 *===========================================================================*/
17736 PUBLIC int size_ok(file_type, tc, dc, sc, dvir, s_vir)
17737 int file_type; /* SEPARATE or 0 */
17738 vir_clicks tc; /* text size in clicks */
17739 vir_clicks dc; /* data size in clicks */
17740 vir_clicks sc; /* stack size in clicks */
17741 vir_clicks dvir; /* virtual address for start of data seg */
17742 vir_clicks s_vir; /* virtual address for start of stack seg */
17743 {
17744 /* Check to see if the sizes are feasible and enough segmentation registers
17745 * exist. On a machine with eight 8K pages, text, data, stack sizes of
17746 * (32K, 16K, 16K) will fit, but (33K, 17K, 13K) will not, even though the
17747 * former is bigger (64K) than the latter (63K). Even on the 8088 this test
17748 * is needed, since the data and stack may not exceed 4096 clicks.
17749 */
17750
17751 #if (CHIP == INTEL && _WORD_SIZE == 2)
17752 int pt, pd, ps; /* segment sizes in pages */
17753
17754 pt = ( (tc << CLICK_SHIFT) + PAGE_SIZE - 1)/PAGE_SIZE;
17755 pd = ( (dc << CLICK_SHIFT) + PAGE_SIZE - 1)/PAGE_SIZE;
17756 ps = ( (sc << CLICK_SHIFT) + PAGE_SIZE - 1)/PAGE_SIZE;
17757
17758 if (file_type == SEPARATE) {
17759 if (pt > MAX_PAGES || pd + ps > MAX_PAGES) return(ENOMEM);
17760 } else {
17761 if (pt + pd + ps > MAX_PAGES) return(ENOMEM);
17762 }
17763 #endif
17764
17765 if (dvir + dc > s_vir) return(ENOMEM);
17766
17767 return(OK);
17768 }
.Op 247 src/mm/signal.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/signal.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
17800 /* This file handles signals, which are asynchronous events and are generally
17801 * a messy and unpleasant business. Signals can be generated by the KILL
17802 * system call, or from the keyboard (SIGINT) or from the clock (SIGALRM).
17803 * In all cases control eventually passes to check_sig() to see which processes
17804 * can be signaled. The actual signaling is done by sig_proc().
17805 *
17806 * The entry points into this file are:
17807 * do_sigaction: perform the SIGACTION system call
17808 * do_sigpending: perform the SIGPENDING system call
17809 * do_sigprocmask: perform the SIGPROCMASK system call
17810 * do_sigreturn: perform the SIGRETURN system call
17811 * do_sigsuspend: perform the SIGSUSPEND system call
17812 * do_kill: perform the KILL system call
17813 * do_ksig: accept a signal originating in the kernel (e.g., SIGINT)
17814 * do_alarm: perform the ALARM system call by calling set_alarm()
17815 * set_alarm: tell the clock task to start or stop a timer
17816 * do_pause: perform the PAUSE system call
17817 * do_reboot: kill all processes, then reboot system
17818 * sig_proc: interrupt or terminate a signaled process
17819 * check_sig: check which processes to signal with sig_proc()
17820 */
17821
17822 #include "mm.h"
17823 #include <sys/stat.h>
17824 #include <minix/callnr.h>
17825 #include <minix/com.h>
17826 #include <signal.h>
17827 #include <sys/sigcontext.h>
17828 #include <string.h>
17829 #include "mproc.h"
17830 #include "param.h"
17831
17832 #define CORE_MODE 0777 /* mode to use on core image files */
17833 #define DUMPED 0200 /* bit set in status when core dumped */
17834 #define DUMP_SIZE ((INT_MAX / BLOCK_SIZE) * BLOCK_SIZE)
17835 /* buffer size for core dumps */
17836
17837 FORWARD _PROTOTYPE( void check_pending, (void) );
17838 FORWARD _PROTOTYPE( void dump_core, (struct mproc *rmp) );
17839 FORWARD _PROTOTYPE( void unpause, (int pro) );
17840
17841
17842 /*===========================================================================*
17843 * do_sigaction *
17844 *===========================================================================*/
17845 PUBLIC int do_sigaction()
17846 {
17847 int r;
17848 struct sigaction svec;
17849 struct sigaction *svp;
17850
17851 if (sig_nr == SIGKILL) return(OK);
17852 if (sig_nr < 1 || sig_nr > _NSIG) return (EINVAL);
17853 svp = &mp->mp_sigact[sig_nr];
17854 if ((struct sigaction *) sig_osa != (struct sigaction *) NULL) {
.Ep 248 src/mm/signal.c
17855 r = sys_copy(MM_PROC_NR,D, (phys_bytes) svp,
17856 who, D, (phys_bytes) sig_osa, (phys_bytes) sizeof(svec));
17857 if (r != OK) return(r);
17858 }
17859
17860 if ((struct sigaction *) sig_nsa == (struct sigaction *) NULL) return(OK);
17861
17862 /* Read in the sigaction structure. */
17863 r = sys_copy(who, D, (phys_bytes) sig_nsa,
17864 MM_PROC_NR, D, (phys_bytes) &svec, (phys_bytes) sizeof(svec));
17865 if (r != OK) return(r);
17866
17867 if (svec.sa_handler == SIG_IGN) {
17868 sigaddset(&mp->mp_ignore, sig_nr);
17869 sigdelset(&mp->mp_sigpending, sig_nr);
17870 sigdelset(&mp->mp_catch, sig_nr);
17871 } else {
17872 sigdelset(&mp->mp_ignore, sig_nr);
17873 if (svec.sa_handler == SIG_DFL)
17874 sigdelset(&mp->mp_catch, sig_nr);
17875 else
17876 sigaddset(&mp->mp_catch, sig_nr);
17877 }
17878 mp->mp_sigact[sig_nr].sa_handler = svec.sa_handler;
17879 sigdelset(&svec.sa_mask, SIGKILL);
17880 mp->mp_sigact[sig_nr].sa_mask = svec.sa_mask;
17881 mp->mp_sigact[sig_nr].sa_flags = svec.sa_flags;
17882 mp->mp_sigreturn = (vir_bytes) sig_ret;
17883 return(OK);
17884 }
17886 /*===========================================================================*
17887 * do_sigpending *
17888 *===========================================================================*/
17889 PUBLIC int do_sigpending()
17890 {
17891 ret_mask = (long) mp->mp_sigpending;
17892 return OK;
17893 }
17895 /*===========================================================================*
17896 * do_sigprocmask *
17897 *===========================================================================*/
17898 PUBLIC int do_sigprocmask()
17899 {
17900 /* Note that the library interface passes the actual mask in sigmask_set,
17901 * not a pointer to the mask, in order to save a sys_copy. Similarly,
17902 * the old mask is placed in the return message which the library
17903 * interface copies (if requested) to the user specified address.
17904 *
17905 * The library interface must set SIG_INQUIRE if the 'act' argument
17906 * is NULL.
17907 */
17908
17909 int i;
17910
17911 ret_mask = (long) mp->mp_sigmask;
17912
17913 switch (sig_how) {
17914 case SIG_BLOCK:
.Op 249 src/mm/signal.c
17915 sigdelset((sigset_t *)&sig_set, SIGKILL);
17916 for (i = 1; i < _NSIG; i++) {
17917 if (sigismember((sigset_t *)&sig_set, i))
17918 sigaddset(&mp->mp_sigmask, i);
17919 }
17920 break;
17921
17922 case SIG_UNBLOCK:
17923 for (i = 1; i < _NSIG; i++) {
17924 if (sigismember((sigset_t *)&sig_set, i))
17925 sigdelset(&mp->mp_sigmask, i);
17926 }
17927 check_pending();
17928 break;
17929
17930 case SIG_SETMASK:
17931 sigdelset((sigset_t *)&sig_set, SIGKILL);
17932 mp->mp_sigmask = (sigset_t)sig_set;
17933 check_pending();
17934 break;
17935
17936 case SIG_INQUIRE:
17937 break;
17938
17939 default:
17940 return(EINVAL);
17941 break;
17942 }
17943 return OK;
17944 }
17946 /*===========================================================================*
17947 * do_sigsuspend *
17948 *===========================================================================*/
17949 PUBLIC int do_sigsuspend()
17950 {
17951 mp->mp_sigmask2 = mp->mp_sigmask; /* save the old mask */
17952 mp->mp_sigmask = (sigset_t) sig_set;
17953 sigdelset(&mp->mp_sigmask, SIGKILL);
17954 mp->mp_flags |= SIGSUSPENDED;
17955 dont_reply = TRUE;
17956 check_pending();
17957 return OK;
17958 }
17961 /*===========================================================================*
17962 * do_sigreturn *
17963 *===========================================================================*/
17964 PUBLIC int do_sigreturn()
17965 {
17966 /* A user signal handler is done. Restore context and check for
17967 * pending unblocked signals.
17968 */
17969
17970 int r;
17971
17972 mp->mp_sigmask = (sigset_t) sig_set;
17973 sigdelset(&mp->mp_sigmask, SIGKILL);
17974
.Ep 250 src/mm/signal.c
17975 r = sys_sigreturn(who, (vir_bytes)sig_context, sig_flags);
17976 check_pending();
17977 return(r);
17978 }
17980 /*===========================================================================*
17981 * do_kill *
17982 *===========================================================================*/
17983 PUBLIC int do_kill()
17984 {
17985 /* Perform the kill(pid, signo) system call. */
17986
17987 return check_sig(pid, sig_nr);
17988 }
17991 /*===========================================================================*
17992 * do_ksig *
17993 *===========================================================================*/
17994 PUBLIC int do_ksig()
17995 {
17996 /* Certain signals, such as segmentation violations and DEL, originate in the
17997 * kernel. When the kernel detects such signals, it sets bits in a bit map.
17998 * As soon as MM is awaiting new work, the kernel sends MM a message containing
17999 * the process slot and bit map. That message comes here. The File System
18000 * also uses this mechanism to signal writing on broken pipes (SIGPIPE).
18001 */
18002
18003 register struct mproc *rmp;
18004 int i, proc_nr;
18005 pid_t proc_id, id;
18006 sigset_t sig_map;
18007
18008 /* Only kernel may make this call. */
18009 if (who != HARDWARE) return(EPERM);
18010 dont_reply = TRUE; /* don't reply to the kernel */
18011 proc_nr = mm_in.SIG_PROC;
18012 rmp = &mproc[proc_nr];
18013 if ( (rmp->mp_flags & IN_USE) == 0 || (rmp->mp_flags & HANGING) ) return(OK);
18014 proc_id = rmp->mp_pid;
18015 sig_map = (sigset_t) mm_in.SIG_MAP;
18016 mp = &mproc[0]; /* pretend kernel signals are from MM */
18017 mp->mp_procgrp = rmp->mp_procgrp; /* get process group right */
18018
18019 /* Check each bit in turn to see if a signal is to be sent. Unlike
18020 * kill(), the kernel may collect several unrelated signals for a
18021 * process and pass them to MM in one blow. Thus loop on the bit
18022 * map. For SIGINT and SIGQUIT, use proc_id 0 to indicate a broadcast
18023 * to the recipient's process group. For SIGKILL, use proc_id -1 to
18024 * indicate a systemwide broadcast.
18025 */
18026 for (i = 1; i <= _NSIG; i++) {
18027 if (!sigismember(&sig_map, i)) continue;
18028 switch (i) {
18029 case SIGINT:
18030 case SIGQUIT:
18031 id = 0; break; /* broadcast to process group */
18032 case SIGKILL:
18033 id = -1; break; /* broadcast to all except INIT */
18034 case SIGALRM:
.Op 251 src/mm/signal.c
18035 /* Disregard SIGALRM when the target process has not
18036 * requested an alarm. This only applies for a KERNEL
18037 * generated signal.
18038 */
18039 if ((rmp->mp_flags & ALARM_ON) == 0) continue;
18040 rmp->mp_flags &= ~ALARM_ON;
18041 /* fall through */
18042 default:
18043 id = proc_id;
18044 break;
18045 }
18046 check_sig(id, i);
18047 sys_endsig(proc_nr); /* tell kernel it's done */
18048 }
18049 return(OK);
18050 }
18053 /*===========================================================================*
18054 * do_alarm *
18055 *===========================================================================*/
18056 PUBLIC int do_alarm()
18057 {
18058 /* Perform the alarm(seconds) system call. */
18059
18060 return(set_alarm(who, seconds));
18061 }
18064 /*===========================================================================*
18065 * set_alarm *
18066 *===========================================================================*/
18067 PUBLIC int set_alarm(proc_nr, sec)
18068 int proc_nr; /* process that wants the alarm */
18069 int sec; /* how many seconds delay before the signal */
18070 {
18071 /* This routine is used by do_alarm() to set the alarm timer. It is also used
18072 * to turn the timer off when a process exits with the timer still on.
18073 */
18074
18075 message m_sig;
18076 int remaining;
18077
18078 if (sec != 0)
18079 mproc[proc_nr].mp_flags |= ALARM_ON;
18080 else
18081 mproc[proc_nr].mp_flags &= ~ALARM_ON;
18082
18083 /* Tell the clock task to provide a signal message when the time comes.
18084 *
18085 * Large delays cause a lot of problems. First, the alarm system call
18086 * takes an unsigned seconds count and the library has cast it to an int.
18087 * That probably works, but on return the library will convert "negative"
18088 * unsigneds to errors. Presumably no one checks for these errors, so
18089 * force this call through. Second, If unsigned and long have the same
18090 * size, converting from seconds to ticks can easily overflow. Finally,
18091 * the kernel has similar overflow bugs adding ticks.
18092 *
18093 * Fixing this requires a lot of ugly casts to fit the wrong interface
18094 * types and to avoid overflow traps. DELTA_TICKS has the right type
.Ep 252 src/mm/signal.c
18095 * (clock_t) although it is declared as long. How can variables like
18096 * this be declared properly without combinatorial explosion of message
18097 * types?
18098 */
18099 m_sig.m_type = SET_ALARM;
18100 m_sig.CLOCK_PROC_NR = proc_nr;
18101 m_sig.DELTA_TICKS = (clock_t) (HZ * (unsigned long) (unsigned) sec);
18102 if ( (unsigned long) m_sig.DELTA_TICKS / HZ != (unsigned) sec)
18103 m_sig.DELTA_TICKS = LONG_MAX; /* eternity (really CLOCK_T_MAX) */
18104 if (sendrec(CLOCK, &m_sig) != OK) panic("alarm er", NO_NUM);
18105 remaining = (int) m_sig.SECONDS_LEFT;
18106 if (remaining != m_sig.SECONDS_LEFT || remaining < 0)
18107 remaining = INT_MAX; /* true value is not representable */
18108 return(remaining);
18109 }
18112 /*===========================================================================*
18113 * do_pause *
18114 *===========================================================================*/
18115 PUBLIC int do_pause()
18116 {
18117 /* Perform the pause() system call. */
18118
18119 mp->mp_flags |= PAUSED;
18120 dont_reply = TRUE;
18121 return(OK);
18122 }
18125 /*=====================================================================*
18126 * do_reboot *
18127 *=====================================================================*/
18128 PUBLIC int do_reboot()
18129 {
18130 register struct mproc *rmp = mp;
18131 char monitor_code[64];
18132
18133 if (rmp->mp_effuid != SUPER_USER) return EPERM;
18134
18135 switch (reboot_flag) {
18136 case RBT_HALT:
18137 case RBT_REBOOT:
18138 case RBT_PANIC:
18139 case RBT_RESET:
18140 break;
18141 case RBT_MONITOR:
18142 if (reboot_size > sizeof(monitor_code)) return EINVAL;
18143 memset(monitor_code, 0, sizeof(monitor_code));
18144 if (sys_copy(who, D, (phys_bytes) reboot_code,
18145 MM_PROC_NR, D, (phys_bytes) monitor_code,
18146 (phys_bytes) reboot_size) != OK) return EFAULT;
18147 if (monitor_code[sizeof(monitor_code)-1] != 0) return EINVAL;
18148 break;
18149 default:
18150 return EINVAL;
18151 }
18152
18153 /* Kill all processes except init. */
18154 check_sig(-1, SIGKILL);
.Op 253 src/mm/signal.c
18155
18156 tell_fs(EXIT, INIT_PROC_NR, 0, 0); /* cleanup init */
18157
18158 tell_fs(SYNC,0,0,0);
18159
18160 sys_abort(reboot_flag, monitor_code);
18161 /* NOTREACHED */
18162 }
18165 /*===========================================================================*
18166 * sig_proc *
18167 *===========================================================================*/
18168 PUBLIC void sig_proc(rmp, signo)
18169 register struct mproc *rmp; /* pointer to the process to be signaled */
18170 int signo; /* signal to send to process (1 to _NSIG) */
18171 {
18172 /* Send a signal to a process. Check to see if the signal is to be caught,
18173 * ignored, or blocked. If the signal is to be caught, coordinate with
18174 * KERNEL to push a sigcontext structure and a sigframe structure onto
18175 * the catcher's stack. Also, KERNEL will reset the program counter and
18176 * stack pointer, so that when the process next runs, it will be executing
18177 * the signal handler. When the signal handler returns, sigreturn(2)
18178 * will be called. Then KERNEL will restore the signal context from the
18179 * sigcontext structure.
18180 *
18181 * If there is insufficient stack space, kill the process.
18182 */
18183
18184 vir_bytes new_sp;
18185 int slot;
18186 int sigflags;
18187 struct sigmsg sm;
18188
18189 slot = (int) (rmp - mproc);
18190 if (!(rmp->mp_flags & IN_USE)) {
18191 printf("MM: signal %d sent to dead process %dn", signo, slot);
18192 panic("", NO_NUM);
18193 }
18194 if (rmp->mp_flags & HANGING) {
18195 printf("MM: signal %d sent to HANGING process %dn", signo, slot);
18196 panic("", NO_NUM);
18197 }
18198 if (rmp->mp_flags & TRACED && signo != SIGKILL) {
18199 /* A traced process has special handling. */
18200 unpause(slot);
18201 stop_proc(rmp, signo); /* a signal causes it to stop */
18202 return;
18203 }
18204 /* Some signals are ignored by default. */
18205 if (sigismember(&rmp->mp_ignore, signo)) return;
18206
18207 if (sigismember(&rmp->mp_sigmask, signo)) {
18208 /* Signal should be blocked. */
18209 sigaddset(&rmp->mp_sigpending, signo);
18210 return;
18211 }
18212 sigflags = rmp->mp_sigact[signo].sa_flags;
18213 if (sigismember(&rmp->mp_catch, signo)) {
18214 if (rmp->mp_flags & SIGSUSPENDED)
.Ep 254 src/mm/signal.c
18215 sm.sm_mask = rmp->mp_sigmask2;
18216 else
18217 sm.sm_mask = rmp->mp_sigmask;
18218 sm.sm_signo = signo;
18219 sm.sm_sighandler = (vir_bytes) rmp->mp_sigact[signo].sa_handler;
18220 sm.sm_sigreturn = rmp->mp_sigreturn;
18221 sys_getsp(slot, &new_sp);
18222 sm.sm_stkptr = new_sp;
18223
18224 /* Make room for the sigcontext and sigframe struct. */
18225 new_sp -= sizeof(struct sigcontext)
18226 + 3 * sizeof(char *) + 2 * sizeof(int);
18227
18228 if (adjust(rmp, rmp->mp_seg[D].mem_len, new_sp) != OK)
18229 goto doterminate;
18230
18231 rmp->mp_sigmask |= rmp->mp_sigact[signo].sa_mask;
18232 if (sigflags & SA_NODEFER)
18233 sigdelset(&rmp->mp_sigmask, signo);
18234 else
18235 sigaddset(&rmp->mp_sigmask, signo);
18236
18237 if (sigflags & SA_RESETHAND) {
18238 sigdelset(&rmp->mp_catch, signo);
18239 rmp->mp_sigact[signo].sa_handler = SIG_DFL;
18240 }
18241
18242 sys_sendsig(slot, &sm);
18243 sigdelset(&rmp->mp_sigpending, signo);
18244 /* If process is hanging on PAUSE, WAIT, SIGSUSPEND, tty, pipe, etc.,
18245 * release it.
18246 */
18247 unpause(slot);
18248 return;
18249 }
18250 doterminate:
18251 /* Signal should not or cannot be caught. Terminate the process. */
18252 rmp->mp_sigstatus = (char) signo;
18253 if (sigismember(&core_sset, signo)) {
18254 /* Switch to the user's FS environment and dump core. */
18255 tell_fs(CHDIR, slot, FALSE, 0);
18256 dump_core(rmp);
18257 }
18258 mm_exit(rmp, 0); /* terminate process */
18259 }
18262 /*===========================================================================*
18263 * check_sig *
18264 *===========================================================================*/
18265 PUBLIC int check_sig(proc_id, signo)
18266 pid_t proc_id; /* pid of proc to sig, or 0 or -1, or -pgrp */
18267 int signo; /* signal to send to process (0 to _NSIG) */
18268 {
18269 /* Check to see if it is possible to send a signal. The signal may have to be
18270 * sent to a group of processes. This routine is invoked by the KILL system
18271 * call, and also when the kernel catches a DEL or other signal.
18272 */
18273
18274 register struct mproc *rmp;
.Op 255 src/mm/signal.c
18275 int count; /* count # of signals sent */
18276 int error_code;
18277
18278 if (signo < 0 || signo > _NSIG) return(EINVAL);
18279
18280 /* Return EINVAL for attempts to send SIGKILL to INIT alone. */
18281 if (proc_id == INIT_PID && signo == SIGKILL) return(EINVAL);
18282
18283 /* Search the proc table for processes to signal. (See forkexit.c about
18284 * pid magic.)
18285 */
18286 count = 0;
18287 error_code = ESRCH;
18288 for (rmp = &mproc[INIT_PROC_NR]; rmp < &mproc[NR_PROCS]; rmp++) {
18289 if ( (rmp->mp_flags & IN_USE) == 0) continue;
18290 if (rmp->mp_flags & HANGING && signo != 0) continue;
18291
18292 /* Check for selection. */
18293 if (proc_id > 0 && proc_id != rmp->mp_pid) continue;
18294 if (proc_id == 0 && mp->mp_procgrp != rmp->mp_procgrp) continue;
18295 if (proc_id == -1 && rmp->mp_pid == INIT_PID) continue;
18296 if (proc_id < -1 && rmp->mp_procgrp != -proc_id) continue;
18297
18298 /* Check for permission. */
18299 if (mp->mp_effuid != SUPER_USER
18300 && mp->mp_realuid != rmp->mp_realuid
18301 && mp->mp_effuid != rmp->mp_realuid
18302 && mp->mp_realuid != rmp->mp_effuid
18303 && mp->mp_effuid != rmp->mp_effuid) {
18304 error_code = EPERM;
18305 continue;
18306 }
18307
18308 count++;
18309 if (signo == 0) continue;
18310
18311 /* 'sig_proc' will handle the disposition of the signal. The
18312 * signal may be caught, blocked, ignored, or cause process
18313 * termination, possibly with core dump.
18314 */
18315 sig_proc(rmp, signo);
18316
18317 if (proc_id > 0) break; /* only one process being signaled */
18318 }
18319
18320 /* If the calling process has killed itself, don't reply. */
18321 if ((mp->mp_flags & IN_USE) == 0 || (mp->mp_flags & HANGING))
18322 dont_reply = TRUE;
18323 return(count > 0 ? OK : error_code);
18324 }
18327 /*===========================================================================*
18328 * check_pending *
18329 *===========================================================================*/
18330 PRIVATE void check_pending()
18331 {
18332 /* Check to see if any pending signals have been unblocked. The
18333 * first such signal found is delivered.
18334 *
.Ep 256 src/mm/signal.c
18335 * If multiple pending unmasked signals are found, they will be
18336 * delivered sequentially.
18337 *
18338 * There are several places in this file where the signal mask is
18339 * changed. At each such place, check_pending() should be called to
18340 * check for newly unblocked signals.
18341 */
18342
18343 int i;
18344
18345 for (i = 1; i < _NSIG; i++) {
18346 if (sigismember(&mp->mp_sigpending, i) &&
18347 !sigismember(&mp->mp_sigmask, i)) {
18348 sigdelset(&mp->mp_sigpending, i);
18349 sig_proc(mp, i);
18350 break;
18351 }
18352 }
18353 }
18356 /*===========================================================================*
18357 * unpause *
18358 *===========================================================================*/
18359 PRIVATE void unpause(pro)
18360 int pro; /* which process number */
18361 {
18362 /* A signal is to be sent to a process. If that process is hanging on a
18363 * system call, the system call must be terminated with EINTR. Possible
18364 * calls are PAUSE, WAIT, READ and WRITE, the latter two for pipes and ttys.
18365 * First check if the process is hanging on an MM call. If not, tell FS,
18366 * so it can check for READs and WRITEs from pipes, ttys and the like.
18367 */
18368
18369 register struct mproc *rmp;
18370
18371 rmp = &mproc[pro];
18372
18373 /* Check to see if process is hanging on a PAUSE call. */
18374 if ( (rmp->mp_flags & PAUSED) && (rmp->mp_flags & HANGING) == 0) {
18375 rmp->mp_flags &= ~PAUSED;
18376 reply(pro, EINTR, 0, NIL_PTR);
18377 return;
18378 }
18379
18380 /* Check to see if process is hanging on a WAIT call. */
18381 if ( (rmp->mp_flags & WAITING) && (rmp->mp_flags & HANGING) == 0) {
18382 rmp->mp_flags &= ~WAITING;
18383 reply(pro, EINTR, 0, NIL_PTR);
18384 return;
18385 }
18386
18387 /* Check to see if process is hanging on a SIGSUSPEND call. */
18388 if ((rmp->mp_flags & SIGSUSPENDED) && (rmp->mp_flags & HANGING) == 0) {
18389 rmp->mp_flags &= ~SIGSUSPENDED;
18390 reply(pro, EINTR, 0, NIL_PTR);
18391 return;
18392 }
18393
18394 /* Process is not hanging on an MM call. Ask FS to take a look. */
.Op 257 src/mm/signal.c
18395 tell_fs(UNPAUSE, pro, 0, 0);
18396 }
18399 /*===========================================================================*
18400 * dump_core *
18401 *===========================================================================*/
18402 PRIVATE void dump_core(rmp)
18403 register struct mproc *rmp; /* whose core is to be dumped */
18404 {
18405 /* Make a core dump on the file "core", if possible. */
18406
18407 int fd, fake_fd, nr_written, seg, slot;
18408 char *buf;
18409 vir_bytes current_sp;
18410 phys_bytes left; /* careful; 64K might overflow vir_bytes */
18411 unsigned nr_to_write; /* unsigned for arg to write() but < INT_MAX */
18412 long trace_data, trace_off;
18413
18414 slot = (int) (rmp - mproc);
18415
18416 /* Can core file be written? We are operating in the user's FS environment,
18417 * so no special permission checks are needed.
18418 */
18419 if (rmp->mp_realuid != rmp->mp_effuid) return;
18420 if ( (fd = creat(core_name, CORE_MODE)) < 0) return;
18421 rmp->mp_sigstatus |= DUMPED;
18422
18423 /* Make sure the stack segment is up to date.
18424 * We don't want adjust() to fail unless current_sp is preposterous,
18425 * but it might fail due to safety checking. Also, we don't really want
18426 * the adjust() for sending a signal to fail due to safety checking.
18427 * Maybe make SAFETY_BYTES a parameter.
18428 */
18429 sys_getsp(slot, &current_sp);
18430 adjust(rmp, rmp->mp_seg[D].mem_len, current_sp);
18431
18432 /* Write the memory map of all segments to begin the core file. */
18433 if (write(fd, (char *) rmp->mp_seg, (unsigned) sizeof rmp->mp_seg)
18434 != (unsigned) sizeof rmp->mp_seg) {
18435 close(fd);
18436 return;
18437 }
18438
18439 /* Write out the whole kernel process table entry to get the regs. */
18440 trace_off = 0;
18441 while (sys_trace(3, slot, trace_off, &trace_data) == OK) {
18442 if (write(fd, (char *) &trace_data, (unsigned) sizeof (long))
18443 != (unsigned) sizeof (long)) {
18444 close(fd);
18445 return;
18446 }
18447 trace_off += sizeof (long);
18448 }
18449
18450 /* Loop through segments and write the segments themselves out. */
18451 for (seg = 0; seg < NR_SEGS; seg++) {
18452 buf = (char *) ((vir_bytes) rmp->mp_seg[seg].mem_vir << CLICK_SHIFT);
18453 left = (phys_bytes) rmp->mp_seg[seg].mem_len << CLICK_SHIFT;
18454 fake_fd = (slot << 8) | (seg << 6) | fd;
.Ep 258 src/mm/signal.c
18455
18456 /* Loop through a segment, dumping it. */
18457 while (left != 0) {
18458 nr_to_write = (unsigned) MIN(left, DUMP_SIZE);
18459 if ( (nr_written = write(fake_fd, buf, nr_to_write)) < 0) {
18460 close(fd);
18461 return;
18462 }
18463 buf += nr_written;
18464 left -= nr_written;
18465 }
18466 }
18467 close(fd);
18468 }
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/getset.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
18500 /* This file handles the 4 system calls that get and set uids and gids.
18501 * It also handles getpid(), setsid(), and getpgrp(). The code for each
18502 * one is so tiny that it hardly seemed worthwhile to make each a separate
18503 * function.
18504 */
18505
18506 #include "mm.h"
18507 #include <minix/callnr.h>
18508 #include <signal.h>
18509 #include "mproc.h"
18510 #include "param.h"
18511
18512 /*===========================================================================*
18513 * do_getset *
18514 *===========================================================================*/
18515 PUBLIC int do_getset()
18516 {
18517 /* Handle GETUID, GETGID, GETPID, GETPGRP, SETUID, SETGID, SETSID. The four
18518 * GETs and SETSID return their primary results in 'r'. GETUID, GETGID, and
18519 * GETPID also return secondary results (the effective IDs, or the parent
18520 * process ID) in 'result2', which is returned to the user.
18521 */
18522
18523 register struct mproc *rmp = mp;
18524 register int r;
18525
18526 switch(mm_call) {
18527 case GETUID:
18528 r = rmp->mp_realuid;
18529 result2 = rmp->mp_effuid;
18530 break;
18531
18532 case GETGID:
18533 r = rmp->mp_realgid;
18534 result2 = rmp->mp_effgid;
18535 break;
18536
18537 case GETPID:
18538 r = mproc[who].mp_pid;
18539 result2 = mproc[rmp->mp_parent].mp_pid;
.Op 259 src/mm/getset.c
18540 break;
18541
18542 case SETUID:
18543 if (rmp->mp_realuid != usr_id && rmp->mp_effuid != SUPER_USER)
18544 return(EPERM);
18545 rmp->mp_realuid = usr_id;
18546 rmp->mp_effuid = usr_id;
18547 tell_fs(SETUID, who, usr_id, usr_id);
18548 r = OK;
18549 break;
18550
18551 case SETGID:
18552 if (rmp->mp_realgid != grpid && rmp->mp_effuid != SUPER_USER)
18553 return(EPERM);
18554 rmp->mp_realgid = grpid;
18555 rmp->mp_effgid = grpid;
18556 tell_fs(SETGID, who, grpid, grpid);
18557 r = OK;
18558 break;
18559
18560 case SETSID:
18561 if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
18562 rmp->mp_procgrp = rmp->mp_pid;
18563 tell_fs(SETSID, who, 0, 0);
18564 /*FALL THROUGH*/
18565
18566 case GETPGRP:
18567 r = rmp->mp_procgrp;
18568 break;
18569
18570 default:
18571 r = EINVAL;
18572 break;
18573 }
18574 return(r);
18575 }
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/trace.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
18600 /* This file handles the memory manager's part of debugging, using the
18601 * ptrace system call. Most of the commands are passed on to the system
18602 * task for completion.
18603 *
18604 * The debugging commands available are:
18605 * T_STOP stop the process
18606 * T_OK enable tracing by parent for this process
18607 * T_GETINS return value from instruction space
18608 * T_GETDATA return value from data space
18609 * T_GETUSER return value from user process table
18610 * T_SETINS set value in instruction space
18611 * T_SETDATA set value in data space
18612 * T_SETUSER set value in user process table
18613 * T_RESUME resume execution
18614 * T_EXIT exit
.Ep 260 src/mm/trace.c
18615 * T_STEP set trace bit
18616 *
18617 * The T_OK and T_EXIT commands are handled here, and the T_RESUME and
18618 * T_STEP commands are partially handled here and completed by the system
18619 * task. The rest are handled entirely by the system task.
18620 */
18621
18622 #include "mm.h"
18623 #include <sys/ptrace.h>
18624 #include <signal.h>
18625 #include "mproc.h"
18626 #include "param.h"
18627
18628 #define NIL_MPROC ((struct mproc *) 0)
18629
18630 FORWARD _PROTOTYPE( struct mproc *findproc, (pid_t lpid) );
18631
18632 /*===========================================================================*
18633 * do_trace *
18634 *===========================================================================*/
18635 PUBLIC int do_trace()
18636 {
18637 register struct mproc *child;
18638
18639 /* the T_OK call is made by the child fork of the debugger before it execs
18640 * the process to be traced
18641 */
18642 if (request == T_OK) {/* enable tracing by parent for this process */
18643 mp->mp_flags |= TRACED;
18644 mm_out.m2_l2 = 0;
18645 return(OK);
18646 }
18647 if ((child = findproc(pid)) == NIL_MPROC || !(child->mp_flags & STOPPED)) {
18648 return(ESRCH);
18649 }
18650 /* all the other calls are made by the parent fork of the debugger to
18651 * control execution of the child
18652 */
18653 switch (request) {
18654 case T_EXIT: /* exit */
18655 mm_exit(child, (int)data);
18656 mm_out.m2_l2 = 0;
18657 return(OK);
18658 case T_RESUME:
18659 case T_STEP: /* resume execution */
18660 if (data < 0 || data > _NSIG) return(EIO);
18661 if (data > 0) { /* issue signal */
18662 child->mp_flags &= ~TRACED; /* so signal is not diverted */
18663 sig_proc(child, (int) data);
18664 child->mp_flags |= TRACED;
18665 }
18666 child->mp_flags &= ~STOPPED;
18667 break;
18668 }
18669 if (sys_trace(request, (int) (child - mproc), taddr, &data) != OK)
18670 return(-errno);
18671 mm_out.m2_l2 = data;
18672 return(OK);
18673 }
.Op 261 src/mm/trace.c
18675 /*===========================================================================*
18676 * findproc *
18677 *===========================================================================*/
18678 PRIVATE struct mproc *findproc(lpid)
18679 pid_t lpid;
18680 {
18681 register struct mproc *rmp;
18682
18683 for (rmp = &mproc[INIT_PROC_NR + 1]; rmp < &mproc[NR_PROCS]; rmp++)
18684 if (rmp->mp_flags & IN_USE && rmp->mp_pid == lpid) return(rmp);
18685 return(NIL_MPROC);
18686 }
18688 /*===========================================================================*
18689 * stop_proc *
18690 *===========================================================================*/
18691 PUBLIC void stop_proc(rmp, signo)
18692 register struct mproc *rmp;
18693 int signo;
18694 {
18695 /* A traced process got a signal so stop it. */
18696
18697 register struct mproc *rpmp = mproc + rmp->mp_parent;
18698
18699 if (sys_trace(-1, (int) (rmp - mproc), 0L, (long *) 0) != OK) return;
18700 rmp->mp_flags |= STOPPED;
18701 if (rpmp->mp_flags & WAITING) {
18702 rpmp->mp_flags &= ~WAITING; /* parent is no longer waiting */
18703 reply(rmp->mp_parent, rmp->mp_pid, 0177 | (signo << 8), NIL_PTR);
18704 } else {
18705 rmp->mp_sigstatus = signo;
18706 }
18707 return;
18708 }
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/alloc.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
18800 /* This file is concerned with allocating and freeing arbitrary-size blocks of
18801 * physical memory on behalf of the FORK and EXEC system calls. The key data
18802 * structure used is the hole table, which maintains a list of holes in memory.
18803 * It is kept sorted in order of increasing memory address. The addresses
18804 * it contains refer to physical memory, starting at absolute address 0
18805 * (i.e., they are not relative to the start of MM). During system
18806 * initialization, that part of memory containing the interrupt vectors,
18807 * kernel, and MM are "allocated" to mark them as not available and to
18808 * remove them from the hole list.
18809 *
18810 * The entry points into this file are:
18811 * alloc_mem: allocate a given sized chunk of memory
18812 * free_mem: release a previously allocated chunk of memory
18813 * mem_init: initialize the tables when MM start up
18814 * max_hole: returns the largest hole currently available
18815 */
18816
18817 #include "mm.h"
18818 #include <minix/com.h>
18819
.Ep 262 src/mm/alloc.c
18820 #define NR_HOLES 128 /* max # entries in hole table */
18821 #define NIL_HOLE (struct hole *) 0
18822
18823 PRIVATE struct hole {
18824 phys_clicks h_base; /* where does the hole begin? */
18825 phys_clicks h_len; /* how big is the hole? */
18826 struct hole *h_next; /* pointer to next entry on the list */
18827 } hole[NR_HOLES];
18828
18829
18830 PRIVATE struct hole *hole_head; /* pointer to first hole */
18831 PRIVATE struct hole *free_slots; /* ptr to list of unused table slots */
18832
18833 FORWARD _PROTOTYPE( void del_slot, (struct hole *prev_ptr, struct hole *hp) );
18834 FORWARD _PROTOTYPE( void merge, (struct hole *hp) );
18835
18836
18837 /*===========================================================================*
18838 * alloc_mem *
18839 *===========================================================================*/
18840 PUBLIC phys_clicks alloc_mem(clicks)
18841 phys_clicks clicks; /* amount of memory requested */
18842 {
18843 /* Allocate a block of memory from the free list using first fit. The block
18844 * consists of a sequence of contiguous bytes, whose length in clicks is
18845 * given by 'clicks'. A pointer to the block is returned. The block is
18846 * always on a click boundary. This procedure is called when memory is
18847 * needed for FORK or EXEC.
18848 */
18849
18850 register struct hole *hp, *prev_ptr;
18851 phys_clicks old_base;
18852
18853 hp = hole_head;
18854 while (hp != NIL_HOLE) {
18855 if (hp->h_len >= clicks) {
18856 /* We found a hole that is big enough. Use it. */
18857 old_base = hp->h_base; /* remember where it started */
18858 hp->h_base += clicks; /* bite a piece off */
18859 hp->h_len -= clicks; /* ditto */
18860
18861 /* If hole is only partly used, reduce size and return. */
18862 if (hp->h_len != 0) return(old_base);
18863
18864 /* The entire hole has been used up. Manipulate free list. */
18865 del_slot(prev_ptr, hp);
18866 return(old_base);
18867 }
18868
18869 prev_ptr = hp;
18870 hp = hp->h_next;
18871 }
18872 return(NO_MEM);
18873 }
18876 /*===========================================================================*
18877 * free_mem *
18878 *===========================================================================*/
18879 PUBLIC void free_mem(base, clicks)
.Op 263 src/mm/alloc.c
18880 phys_clicks base; /* base address of block to free */
18881 phys_clicks clicks; /* number of clicks to free */
18882 {
18883 /* Return a block of free memory to the hole list. The parameters tell where
18884 * the block starts in physical memory and how big it is. The block is added
18885 * to the hole list. If it is contiguous with an existing hole on either end,
18886 * it is merged with the hole or holes.
18887 */
18888
18889 register struct hole *hp, *new_ptr, *prev_ptr;
18890
18891 if (clicks == 0) return;
18892 if ( (new_ptr = free_slots) == NIL_HOLE) panic("Hole table full", NO_NUM);
18893 new_ptr->h_base = base;
18894 new_ptr->h_len = clicks;
18895 free_slots = new_ptr->h_next;
18896 hp = hole_head;
18897
18898 /* If this block's address is numerically less than the lowest hole currently
18899 * available, or if no holes are currently available, put this hole on the
18900 * front of the hole list.
18901 */
18902 if (hp == NIL_HOLE || base <= hp->h_base) {
18903 /* Block to be freed goes on front of the hole list. */
18904 new_ptr->h_next = hp;
18905 hole_head = new_ptr;
18906 merge(new_ptr);
18907 return;
18908 }
18909
18910 /* Block to be returned does not go on front of hole list. */
18911 while (hp != NIL_HOLE && base > hp->h_base) {
18912 prev_ptr = hp;
18913 hp = hp->h_next;
18914 }
18915
18916 /* We found where it goes. Insert block after 'prev_ptr'. */
18917 new_ptr->h_next = prev_ptr->h_next;
18918 prev_ptr->h_next = new_ptr;
18919 merge(prev_ptr); /* sequence is 'prev_ptr', 'new_ptr', 'hp' */
18920 }
18923 /*===========================================================================*
18924 * del_slot *
18925 *===========================================================================*/
18926 PRIVATE void del_slot(prev_ptr, hp)
18927 register struct hole *prev_ptr; /* pointer to hole entry just ahead of 'hp' */
18928 register struct hole *hp; /* pointer to hole entry to be removed */
18929 {
18930 /* Remove an entry from the hole list. This procedure is called when a
18931 * request to allocate memory removes a hole in its entirety, thus reducing
18932 * the numbers of holes in memory, and requiring the elimination of one
18933 * entry in the hole list.
18934 */
18935
18936 if (hp == hole_head)
18937 hole_head = hp->h_next;
18938 else
18939 prev_ptr->h_next = hp->h_next;
.Ep 264 src/mm/alloc.c
18940
18941 hp->h_next = free_slots;
18942 free_slots = hp;
18943 }
18946 /*===========================================================================*
18947 * merge *
18948 *===========================================================================*/
18949 PRIVATE void merge(hp)
18950 register struct hole *hp; /* ptr to hole to merge with its successors */
18951 {
18952 /* Check for contiguous holes and merge any found. Contiguous holes can occur
18953 * when a block of memory is freed, and it happens to abut another hole on
18954 * either or both ends. The pointer 'hp' points to the first of a series of
18955 * three holes that can potentially all be merged together.
18956 */
18957
18958 register struct hole *next_ptr;
18959
18960 /* If 'hp' points to the last hole, no merging is possible. If it does not,
18961 * try to absorb its successor into it and free the successor's table entry.
18962 */
18963 if ( (next_ptr = hp->h_next) == NIL_HOLE) return;
18964 if (hp->h_base + hp->h_len == next_ptr->h_base) {
18965 hp->h_len += next_ptr->h_len; /* first one gets second one's mem */
18966 del_slot(hp, next_ptr);
18967 } else {
18968 hp = next_ptr;
18969 }
18970
18971 /* If 'hp' now points to the last hole, return; otherwise, try to absorb its
18972 * successor into it.
18973 */
18974 if ( (next_ptr = hp->h_next) == NIL_HOLE) return;
18975 if (hp->h_base + hp->h_len == next_ptr->h_base) {
18976 hp->h_len += next_ptr->h_len;
18977 del_slot(hp, next_ptr);
18978 }
18979 }
18982 /*===========================================================================*
18983 * max_hole *
18984 *===========================================================================*/
18985 PUBLIC phys_clicks max_hole()
18986 {
18987 /* Scan the hole list and return the largest hole. */
18988
18989 register struct hole *hp;
18990 register phys_clicks max;
18991
18992 hp = hole_head;
18993 max = 0;
18994 while (hp != NIL_HOLE) {
18995 if (hp->h_len > max) max = hp->h_len;
18996 hp = hp->h_next;
18997 }
18998 return(max);
18999 }
.Op 265 src/mm/alloc.c
19002 /*===========================================================================*
19003 * mem_init *
19004 *===========================================================================*/
19005 PUBLIC void mem_init(total, free)
19006 phys_clicks *total, *free; /* memory size summaries */
19007 {
19008 /* Initialize hole lists. There are two lists: 'hole_head' points to a linked
19009 * list of all the holes (unused memory) in the system; 'free_slots' points to
19010 * a linked list of table entries that are not in use. Initially, the former
19011 * list has one entry for each chunk of physical memory, and the second
19012 * list links together the remaining table slots. As memory becomes more
19013 * fragmented in the course of time (i.e., the initial big holes break up into
19014 * smaller holes), new table slots are needed to represent them. These slots
19015 * are taken from the list headed by 'free_slots'.
19016 */
19017
19018 register struct hole *hp;
19019 phys_clicks base; /* base address of chunk */
19020 phys_clicks size; /* size of chunk */
19021 message mess;
19022
19023 /* Put all holes on the free list. */
19024 for (hp = &hole[0]; hp < &hole[NR_HOLES]; hp++) hp->h_next = hp + 1;
19025 hole[NR_HOLES-1].h_next = NIL_HOLE;
19026 hole_head = NIL_HOLE;
19027 free_slots = &hole[0];
19028
19029 /* Ask the kernel for chunks of physical memory and allocate a hole for
19030 * each of them. The SYS_MEM call responds with the base and size of the
19031 * next chunk and the total amount of memory.
19032 */
19033 *free = 0;
19034 for (;;) {
19035 mess.m_type = SYS_MEM;
19036 if (sendrec(SYSTASK, &mess) != OK) panic("bad SYS_MEM?", NO_NUM);
19037 base = mess.m1_i1;
19038 size = mess.m1_i2;
19039 if (size == 0) break; /* no more? */
19040
19041 free_mem(base, size);
19042 *total = mess.m1_i3;
19043 *free += size;
19044 }
19045 }
.Ep 266 src/mm/utility.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/utility.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19100 /* This file contains some utility routines for MM.
19101 *
19102 * The entry points are:
19103 * allowed: see if an access is permitted
19104 * no_sys: this routine is called for invalid system call numbers
19105 * panic: MM has run aground of a fatal error and cannot continue
19106 * tell_fs: interface to FS
19107 */
19108
19109 #include "mm.h"
19110 #include <sys/stat.h>
19111 #include <minix/callnr.h>
19112 #include <minix/com.h>
19113 #include <fcntl.h>
19114 #include <signal.h> /* needed only because mproc.h needs it */
19115 #include "mproc.h"
19116
19117 /*===========================================================================*
19118 * allowed *
19119 *===========================================================================*/
19120 PUBLIC int allowed(name_buf, s_buf, mask)
19121 char *name_buf; /* pointer to file name to be EXECed */
19122 struct stat *s_buf; /* buffer for doing and returning stat struct*/
19123 int mask; /* R_BIT, W_BIT, or X_BIT */
19124 {
19125 /* Check to see if file can be accessed. Return EACCES or ENOENT if the access
19126 * is prohibited. If it is legal open the file and return a file descriptor.
19127 */
19128
19129 int fd;
19130 int save_errno;
19131
19132 /* Use the fact that mask for access() is the same as the permissions mask.
19133 * E.g., X_BIT in <minix/const.h> is the same as X_OK in <unistd.h> and
19134 * S_IXOTH in <sys/stat.h>. tell_fs(DO_CHDIR, ...) has set MM's real ids
19135 * to the user's effective ids, so access() works right for setuid programs.
19136 */
19137 if (access(name_buf, mask) < 0) return(-errno);
19138
19139 /* The file is accessible but might not be readable. Make it readable. */
19140 tell_fs(SETUID, MM_PROC_NR, (int) SUPER_USER, (int) SUPER_USER);
19141
19142 /* Open the file and fstat it. Restore the ids early to handle errors. */
19143 fd = open(name_buf, O_RDONLY);
19144 save_errno = errno; /* open might fail, e.g. from ENFILE */
19145 tell_fs(SETUID, MM_PROC_NR, (int) mp->mp_effuid, (int) mp->mp_effuid);
19146 if (fd < 0) return(-save_errno);
19147 if (fstat(fd, s_buf) < 0) panic("allowed: fstat failed", NO_NUM);
19148
19149 /* Only regular files can be executed. */
19150 if (mask == X_BIT && (s_buf->st_mode & I_TYPE) != I_REGULAR) {
19151 close(fd);
19152 return(EACCES);
19153 }
19154 return(fd);
.Op 267 src/mm/utility.c
19155 }
19158 /*===========================================================================*
19159 * no_sys *
19160 *===========================================================================*/
19161 PUBLIC int no_sys()
19162 {
19163 /* A system call number not implemented by MM has been requested. */
19164
19165 return(EINVAL);
19166 }
19169 /*===========================================================================*
19170 * panic *
19171 *===========================================================================*/
19172 PUBLIC void panic(format, num)
19173 char *format; /* format string */
19174 int num; /* number to go with format string */
19175 {
19176 /* Something awful has happened. Panics are caused when an internal
19177 * inconsistency is detected, e.g., a programming error or illegal value of a
19178 * defined constant.
19179 */
19180
19181 printf("Memory manager panic: %s ", format);
19182 if (num != NO_NUM) printf("%d",num);
19183 printf("n");
19184 tell_fs(SYNC, 0, 0, 0); /* flush the cache to the disk */
19185 sys_abort(RBT_PANIC);
19186 }
19189 /*===========================================================================*
19190 * tell_fs *
19191 *===========================================================================*/
19192 PUBLIC void tell_fs(what, p1, p2, p3)
19193 int what, p1, p2, p3;
19194 {
19195 /* This routine is only used by MM to inform FS of certain events:
19196 * tell_fs(CHDIR, slot, dir, 0)
19197 * tell_fs(EXEC, proc, 0, 0)
19198 * tell_fs(EXIT, proc, 0, 0)
19199 * tell_fs(FORK, parent, child, pid)
19200 * tell_fs(SETGID, proc, realgid, effgid)
19201 * tell_fs(SETSID, proc, 0, 0)
19202 * tell_fs(SETUID, proc, realuid, effuid)
19203 * tell_fs(SYNC, 0, 0, 0)
19204 * tell_fs(UNPAUSE, proc, signr, 0)
19205 */
19206
19207 message m;
19208
19209 m.m1_i1 = p1;
19210 m.m1_i2 = p2;
19211 m.m1_i3 = p3;
19212 _taskcall(FS_PROC_NR, what, &m);
19213 }
.Ep 268 src/mm/putk.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/mm/putk.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19300 /* MM must occasionally print some message. It uses the standard library
19301 * routine printk(). (The name "printf" is really a macro defined as
19302 * "printk"). Printing is done by calling the TTY task directly, not going
19303 * through FS.
19304 */
19305
19306 #include "mm.h"
19307 #include <minix/com.h>
19308
19309 #define BUF_SIZE 100 /* print buffer size */
19310
19311 PRIVATE int buf_count; /* # characters in the buffer */
19312 PRIVATE char print_buf[BUF_SIZE]; /* output is buffered here */
19313 PRIVATE message putch_msg; /* used for message to TTY task */
19314
19315 _PROTOTYPE( FORWARD void flush, (void) );
19316
19317 /*===========================================================================*
19318 * putk *
19319 *===========================================================================*/
19320 PUBLIC void putk(c)
19321 int c;
19322 {
19323 /* Accumulate another character. If 0 or buffer full, print it. */
19324
19325 if (c == 0 || buf_count == BUF_SIZE) flush();
19326 if (c == 'n') putk('r');
19327 if (c != 0) print_buf[buf_count++] = c;
19328 }
19331 /*===========================================================================*
19332 * flush *
19333 *===========================================================================*/
19334 PRIVATE void flush()
19335 {
19336 /* Flush the print buffer by calling TTY task. */
19337
19338 if (buf_count == 0) return;
19339 putch_msg.m_type = DEV_WRITE;
19340 putch_msg.PROC_NR = 0;
19341 putch_msg.TTY_LINE = 0;
19342 putch_msg.ADDRESS = print_buf;
19343 putch_msg.COUNT = buf_count;
19344 sendrec(TTY, &putch_msg);
19345 buf_count = 0;
19346 }
.Op 269 src/fs/fs.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/fs.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19400 /* This is the master header for fs. It includes some other files
19401 * and defines the principal constants.
19402 */
19403 #define _POSIX_SOURCE 1 /* tell headers to include POSIX stuff */
19404 #define _MINIX 1 /* tell headers to include MINIX stuff */
19405 #define _SYSTEM 1 /* tell headers that this is the kernel */
19406
19407 /* The following are so basic, all the *.c files get them automatically. */
19408 #include <minix/config.h> /* MUST be first */
19409 #include <ansi.h> /* MUST be second */
19410 #include <sys/types.h>
19411 #include <minix/const.h>
19412 #include <minix/type.h>
19413
19414 #include <limits.h>
19415 #include <errno.h>
19416
19417 #include <minix/syslib.h>
19418
19419 #include "const.h"
19420 #include "type.h"
19421 #include "proto.h"
19422 #include "glo.h"
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/const.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19500 /* Tables sizes */
19501 #define V1_NR_DZONES 7 /* # direct zone numbers in a V1 inode */
19502 #define V1_NR_TZONES 9 /* total # zone numbers in a V1 inode */
19503 #define V2_NR_DZONES 7 /* # direct zone numbers in a V2 inode */
19504 #define V2_NR_TZONES 10 /* total # zone numbers in a V2 inode */
19505
19506 #define NR_FILPS 128 /* # slots in filp table */
19507 #define NR_INODES 64 /* # slots in "in core" inode table */
19508 #define NR_SUPERS 8 /* # slots in super block table */
19509 #define NR_LOCKS 8 /* # slots in the file locking table */
19510
19511 /* The type of sizeof may be (unsigned) long. Use the following macro for
19512 * taking the sizes of small objects so that there are no surprises like
19513 * (small) long constants being passed to routines expecting an int.
19514 */
19515 #define usizeof(t) ((unsigned) sizeof(t))
19516
19517 /* File system types. */
19518 #define SUPER_MAGIC 0x137F /* magic number contained in super-block */
19519 #define SUPER_REV 0x7F13 /* magic # when 68000 disk read on PC or vv */
19520 #define SUPER_V2 0x2468 /* magic # for V2 file systems */
19521 #define SUPER_V2_REV 0x6824 /* V2 magic written on PC, read on 68K or vv */
19522
19523 #define V1 1 /* version number of V1 file systems */
19524 #define V2 2 /* version number of V2 file systems */
.Ep 270 src/fs/const.h
19525
19526 /* Miscellaneous constants */
19527 #define SU_UID ((uid_t) 0) /* super_user's uid_t */
19528 #define SYS_UID ((uid_t) 0) /* uid_t for processes MM and INIT */
19529 #define SYS_GID ((gid_t) 0) /* gid_t for processes MM and INIT */
19530 #define NORMAL 0 /* forces get_block to do disk read */
19531 #define NO_READ 1 /* prevents get_block from doing disk read */
19532 #define PREFETCH 2 /* tells get_block not to read or mark dev */
19533
19534 #define XPIPE (-NR_TASKS-1) /* used in fp_task when susp'd on pipe */
19535 #define XOPEN (-NR_TASKS-2) /* used in fp_task when susp'd on open */
19536 #define XLOCK (-NR_TASKS-3) /* used in fp_task when susp'd on lock */
19537 #define XPOPEN (-NR_TASKS-4) /* used in fp_task when susp'd on pipe open */
19538
19539 #define NO_BIT ((bit_t) 0) /* returned by alloc_bit() to signal failure */
19540
19541 #define DUP_MASK 0100 /* mask to distinguish dup2 from dup */
19542
19543 #define LOOK_UP 0 /* tells search_dir to lookup string */
19544 #define ENTER 1 /* tells search_dir to make dir entry */
19545 #define DELETE 2 /* tells search_dir to delete entry */
19546 #define IS_EMPTY 3 /* tells search_dir to ret. OK or ENOTEMPTY */
19547
19548 #define CLEAN 0 /* disk and memory copies identical */
19549 #define DIRTY 1 /* disk and memory copies differ */
19550 #define ATIME 002 /* set if atime field needs updating */
19551 #define CTIME 004 /* set if ctime field needs updating */
19552 #define MTIME 010 /* set if mtime field needs updating */
19553
19554 #define BYTE_SWAP 0 /* tells conv2/conv4 to swap bytes */
19555 #define DONT_SWAP 1 /* tells conv2/conv4 not to swap bytes */
19556
19557 #define END_OF_FILE (-104) /* eof detected */
19558
19559 #define ROOT_INODE 1 /* inode number for root directory */
19560 #define BOOT_BLOCK ((block_t) 0) /* block number of boot block */
19561 #define SUPER_BLOCK ((block_t) 1) /* block number of super block */
19562
19563 #define DIR_ENTRY_SIZE usizeof (struct direct) /* # bytes/dir entry */
19564 #define NR_DIR_ENTRIES (BLOCK_SIZE/DIR_ENTRY_SIZE) /* # dir entries/blk */
19565 #define SUPER_SIZE usizeof (struct super_block) /* super_block size */
19566 #define PIPE_SIZE (V1_NR_DZONES*BLOCK_SIZE) /* pipe size in bytes */
19567 #define BITMAP_CHUNKS (BLOCK_SIZE/usizeof (bitchunk_t))/* # map chunks/blk */
19568
19569 /* Derived sizes pertaining to the V1 file system. */
19570 #define V1_ZONE_NUM_SIZE usizeof (zone1_t) /* # bytes in V1 zone */
19571 #define V1_INODE_SIZE usizeof (d1_inode) /* bytes in V1 dsk ino */
19572 #define V1_INDIRECTS (BLOCK_SIZE/V1_ZONE_NUM_SIZE) /* # zones/indir block */
19573 #define V1_INODES_PER_BLOCK (BLOCK_SIZE/V1_INODE_SIZE)/* # V1 dsk inodes/blk */
19574
19575 /* Derived sizes pertaining to the V2 file system. */
19576 #define V2_ZONE_NUM_SIZE usizeof (zone_t) /* # bytes in V2 zone */
19577 #define V2_INODE_SIZE usizeof (d2_inode) /* bytes in V2 dsk ino */
19578 #define V2_INDIRECTS (BLOCK_SIZE/V2_ZONE_NUM_SIZE) /* # zones/indir block */
19579 #define V2_INODES_PER_BLOCK (BLOCK_SIZE/V2_INODE_SIZE)/* # V2 dsk inodes/blk */
19580
19581 #define printf printk
.Op 271 src/fs/type.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/type.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19600 /* Declaration of the V1 inode as it is on the disk (not in core). */
19601 typedef struct { /* V1.x disk inode */
19602 mode_t d1_mode; /* file type, protection, etc. */
19603 uid_t d1_uid; /* user id of the file's owner */
19604 off_t d1_size; /* current file size in bytes */
19605 time_t d1_mtime; /* when was file data last changed */
19606 gid_t d1_gid; /* group number */
19607 nlink_t d1_nlinks; /* how many links to this file */
19608 u16_t d1_zone[V1_NR_TZONES]; /* block nums for direct, ind, and dbl ind */
19609 } d1_inode;
19610
19611 /* Declaration of the V2 inode as it is on the disk (not in core). */
19612 typedef struct { /* V2.x disk inode */
19613 mode_t d2_mode; /* file type, protection, etc. */
19614 u16_t d2_nlinks; /* how many links to this file. HACK! */
19615 uid_t d2_uid; /* user id of the file's owner. */
19616 u16_t d2_gid; /* group number HACK! */
19617 off_t d2_size; /* current file size in bytes */
19618 time_t d2_atime; /* when was file data last accessed */
19619 time_t d2_mtime; /* when was file data last changed */
19620 time_t d2_ctime; /* when was inode data last changed */
19621 zone_t d2_zone[V2_NR_TZONES]; /* block nums for direct, ind, and dbl ind */
19622 } d2_inode;
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/proto.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19700 /* Function prototypes. */
19701
19702 /* Structs used in prototypes must be declared as such first. */
19703 struct buf;
19704 struct filp;
19705 struct inode;
19706 struct super_block;
19707
19708 /* cache.c */
19709 _PROTOTYPE( zone_t alloc_zone, (Dev_t dev, zone_t z) );
19710 _PROTOTYPE( void flushall, (Dev_t dev) );
19711 _PROTOTYPE( void free_zone, (Dev_t dev, zone_t numb) );
19712 _PROTOTYPE( struct buf *get_block, (Dev_t dev, block_t block,int only_search));
19713 _PROTOTYPE( void invalidate, (Dev_t device) );
19714 _PROTOTYPE( void put_block, (struct buf *bp, int block_type) );
19715 _PROTOTYPE( void rw_block, (struct buf *bp, int rw_flag) );
19716 _PROTOTYPE( void rw_scattered, (Dev_t dev,
19717 struct buf **bufq, int bufqsize, int rw_flag) );
19718
19719 /* device.c */
19720 _PROTOTYPE( void call_task, (int task_nr, message *mess_ptr) );
19721 _PROTOTYPE( void dev_opcl, (int task_nr, message *mess_ptr) );
19722 _PROTOTYPE( int dev_io, (int rw_flag, int nonblock, Dev_t dev,
19723 off_t pos, int bytes, int proc, char *buff) );
19724 _PROTOTYPE( int do_ioctl, (void) );
.Ep 272 src/fs/proto.h
19725 _PROTOTYPE( void no_dev, (int task_nr, message *m_ptr) );
19726 _PROTOTYPE( void call_ctty, (int task_nr, message *mess_ptr) );
19727 _PROTOTYPE( void tty_open, (int task_nr, message *mess_ptr) );
19728 _PROTOTYPE( void ctty_close, (int task_nr, message *mess_ptr) );
19729 _PROTOTYPE( void ctty_open, (int task_nr, message *mess_ptr) );
19730 _PROTOTYPE( int do_setsid, (void) );
19731 #if ENABLE_NETWORKING
19732 _PROTOTYPE( void net_open, (int task_nr, message *mess_ptr) );
19733 #else
19734 #define net_open 0
19735 #endif
19736
19737 /* filedes.c */
19738 _PROTOTYPE( struct filp *find_filp, (struct inode *rip, Mode_t bits) );
19739 _PROTOTYPE( int get_fd, (int start, Mode_t bits, int *k, struct filp **fpt) );
19740 _PROTOTYPE( struct filp *get_filp, (int fild) );
19741
19742 /* inode.c */
19743 _PROTOTYPE( struct inode *alloc_inode, (Dev_t dev, Mode_t bits) );
19744 _PROTOTYPE( void dup_inode, (struct inode *ip) );
19745 _PROTOTYPE( void free_inode, (Dev_t dev, Ino_t numb) );
19746 _PROTOTYPE( struct inode *get_inode, (Dev_t dev, int numb) );
19747 _PROTOTYPE( void put_inode, (struct inode *rip) );
19748 _PROTOTYPE( void update_times, (struct inode *rip) );
19749 _PROTOTYPE( void rw_inode, (struct inode *rip, int rw_flag) );
19750 _PROTOTYPE( void wipe_inode, (struct inode *rip) );
19751
19752 /* link.c */
19753 _PROTOTYPE( int do_link, (void) );
19754 _PROTOTYPE( int do_unlink, (void) );
19755 _PROTOTYPE( int do_rename, (void) );
19756 _PROTOTYPE( void truncate, (struct inode *rip) );
19757
19758 /* lock.c */
19759 _PROTOTYPE( int lock_op, (struct filp *f, int req) );
19760 _PROTOTYPE( void lock_revive, (void) );
19761
19762 /* main.c */
19763 _PROTOTYPE( void main, (void) );
19764 _PROTOTYPE( void reply, (int whom, int result) );
19765
19766 /* misc.c */
19767 _PROTOTYPE( int do_dup, (void) );
19768 _PROTOTYPE( int do_exit, (void) );
19769 _PROTOTYPE( int do_fcntl, (void) );
19770 _PROTOTYPE( int do_fork, (void) );
19771 _PROTOTYPE( int do_exec, (void) );
19772 _PROTOTYPE( int do_revive, (void) );
19773 _PROTOTYPE( int do_set, (void) );
19774 _PROTOTYPE( int do_sync, (void) );
19775
19776 /* mount.c */
19777 _PROTOTYPE( int do_mount, (void) );
19778 _PROTOTYPE( int do_umount, (void) );
19779
19780 /* open.c */
19781 _PROTOTYPE( int do_close, (void) );
19782 _PROTOTYPE( int do_creat, (void) );
19783 _PROTOTYPE( int do_lseek, (void) );
19784 _PROTOTYPE( int do_mknod, (void) );
.Op 273 src/fs/proto.h
19785 _PROTOTYPE( int do_mkdir, (void) );
19786 _PROTOTYPE( int do_open, (void) );
19787
19788 /* path.c */
19789 _PROTOTYPE( struct inode *advance,(struct inode *dirp, char string[NAME_MAX]));
19790 _PROTOTYPE( int search_dir, (struct inode *ldir_ptr,
19791 char string [NAME_MAX], ino_t *numb, int flag) );
19792 _PROTOTYPE( struct inode *eat_path, (char *path) );
19793 _PROTOTYPE( struct inode *last_dir, (char *path, char string [NAME_MAX]));
19794
19795 /* pipe.c */
19796 _PROTOTYPE( int do_pipe, (void) );
19797 _PROTOTYPE( int do_unpause, (void) );
19798 _PROTOTYPE( int pipe_check, (struct inode *rip, int rw_flag,
19799 int oflags, int bytes, off_t position, int *canwrite));
19800 _PROTOTYPE( void release, (struct inode *ip, int call_nr, int count) );
19801 _PROTOTYPE( void revive, (int proc_nr, int bytes) );
19802 _PROTOTYPE( void suspend, (int task) );
19803
19804 /* protect.c */
19805 _PROTOTYPE( int do_access, (void) );
19806 _PROTOTYPE( int do_chmod, (void) );
19807 _PROTOTYPE( int do_chown, (void) );
19808 _PROTOTYPE( int do_umask, (void) );
19809 _PROTOTYPE( int forbidden, (struct inode *rip, Mode_t access_desired) );
19810 _PROTOTYPE( int read_only, (struct inode *ip) );
19811
19812 /* putk.c */
19813 _PROTOTYPE( void putk, (int c) );
19814
19815 /* read.c */
19816 _PROTOTYPE( int do_read, (void) );
19817 _PROTOTYPE( struct buf *rahead, (struct inode *rip, block_t baseblock,
19818 off_t position, unsigned bytes_ahead) );
19819 _PROTOTYPE( void read_ahead, (void) );
19820 _PROTOTYPE( block_t read_map, (struct inode *rip, off_t position) );
19821 _PROTOTYPE( int read_write, (int rw_flag) );
19822 _PROTOTYPE( zone_t rd_indir, (struct buf *bp, int index) );
19823
19824 /* stadir.c */
19825 _PROTOTYPE( int do_chdir, (void) );
19826 _PROTOTYPE( int do_chroot, (void) );
19827 _PROTOTYPE( int do_fstat, (void) );
19828 _PROTOTYPE( int do_stat, (void) );
19829
19830 /* super.c */
19831 _PROTOTYPE( bit_t alloc_bit, (struct super_block *sp, int map, bit_t origin));
19832 _PROTOTYPE( void free_bit, (struct super_block *sp, int map,
19833 bit_t bit_returned) );
19834 _PROTOTYPE( struct super_block *get_super, (Dev_t dev) );
19835 _PROTOTYPE( int mounted, (struct inode *rip) );
19836 _PROTOTYPE( int read_super, (struct super_block *sp) );
19837
19838 /* time.c */
19839 _PROTOTYPE( int do_stime, (void) );
19840 _PROTOTYPE( int do_time, (void) );
19841 _PROTOTYPE( int do_tims, (void) );
19842 _PROTOTYPE( int do_utime, (void) );
19843
19844 /* utility.c */
.Ep 274 src/fs/proto.h
19845 _PROTOTYPE( time_t clock_time, (void) );
19846 _PROTOTYPE( unsigned conv2, (int norm, int w) );
19847 _PROTOTYPE( long conv4, (int norm, long x) );
19848 _PROTOTYPE( int fetch_name, (char *path, int len, int flag) );
19849 _PROTOTYPE( int no_sys, (void) );
19850 _PROTOTYPE( void panic, (char *format, int num) );
19851
19852 /* write.c */
19853 _PROTOTYPE( void clear_zone, (struct inode *rip, off_t pos, int flag) );
19854 _PROTOTYPE( int do_write, (void) );
19855 _PROTOTYPE( struct buf *new_block, (struct inode *rip, off_t position) );
19856 _PROTOTYPE( void zero_block, (struct buf *bp) );
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/glo.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
19900 /* EXTERN should be extern except for the table file */
19901 #ifdef _TABLE
19902 #undef EXTERN
19903 #define EXTERN
19904 #endif
19905
19906 /* File System global variables */
19907 EXTERN struct fproc *fp; /* pointer to caller's fproc struct */
19908 EXTERN int super_user; /* 1 if caller is super_user, else 0 */
19909 EXTERN int dont_reply; /* normally 0; set to 1 to inhibit reply */
19910 EXTERN int susp_count; /* number of procs suspended on pipe */
19911 EXTERN int nr_locks; /* number of locks currently in place */
19912 EXTERN int reviving; /* number of pipe processes to be revived */
19913 EXTERN off_t rdahedpos; /* position to read ahead */
19914 EXTERN struct inode *rdahed_inode; /* pointer to inode to read ahead */
19915
19916 /* The parameters of the call are kept here. */
19917 EXTERN message m; /* the input message itself */
19918 EXTERN message m1; /* the output message used for reply */
19919 EXTERN int who; /* caller's proc number */
19920 EXTERN int fs_call; /* system call number */
19921 EXTERN char user_path[PATH_MAX];/* storage for user path name */
19922
19923 /* The following variables are used for returning results to the caller. */
19924 EXTERN int err_code; /* temporary storage for error number */
19925 EXTERN int rdwt_err; /* status of last disk i/o request */
19926
19927 /* Data which need initialization. */
19928 extern _PROTOTYPE (int (*call_vector[]), (void) ); /* sys call table */
19929 extern int max_major; /* maximum major device (+ 1) */
19930 extern char dot1[2]; /* dot1 (&dot1[0]) and dot2 (&dot2[0]) have a special */
19931 extern char dot2[3]; /* meaning to search_dir: no access permission check. */
.Op 275 src/fs/fproc.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/fproc.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20000 /* This is the per-process information. A slot is reserved for each potential
20001 * process. Thus NR_PROCS must be the same as in the kernel. It is not possible
20002 * or even necessary to tell when a slot is free here.
20003 */
20004
20005
20006 EXTERN struct fproc {
20007 mode_t fp_umask; /* mask set by umask system call */
20008 struct inode *fp_workdir; /* pointer to working directory's inode */
20009 struct inode *fp_rootdir; /* pointer to current root dir (see chroot) */
20010 struct filp *fp_filp[OPEN_MAX];/* the file descriptor table */
20011 uid_t fp_realuid; /* real user id */
20012 uid_t fp_effuid; /* effective user id */
20013 gid_t fp_realgid; /* real group id */
20014 gid_t fp_effgid; /* effective group id */
20015 dev_t fp_tty; /* major/minor of controlling tty */
20016 int fp_fd; /* place to save fd if rd/wr can't finish */
20017 char *fp_buffer; /* place to save buffer if rd/wr can't finish*/
20018 int fp_nbytes; /* place to save bytes if rd/wr can't finish */
20019 int fp_cum_io_partial; /* partial byte count if rd/wr can't finish */
20020 char fp_suspended; /* set to indicate process hanging */
20021 char fp_revived; /* set to indicate process being revived */
20022 char fp_task; /* which task is proc suspended on */
20023 char fp_sesldr; /* true if proc is a session leader */
20024 pid_t fp_pid; /* process id */
20025 long fp_cloexec; /* bit map for POSIX Table 6-2 FD_CLOEXEC */
20026 } fproc[NR_PROCS];
20027
20028 /* Field values. */
20029 #define NOT_SUSPENDED 0 /* process is not suspended on pipe or task */
20030 #define SUSPENDED 1 /* process is suspended on pipe or task */
20031 #define NOT_REVIVING 0 /* process is not being revived */
20032 #define REVIVING 1 /* process is being revived from suspension */
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/buf.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20100 /* Buffer (block) cache. To acquire a block, a routine calls get_block(),
20101 * telling which block it wants. The block is then regarded as "in use"
20102 * and has its 'b_count' field incremented. All the blocks that are not
20103 * in use are chained together in an LRU list, with 'front' pointing
20104 * to the least recently used block, and 'rear' to the most recently used
20105 * block. A reverse chain, using the field b_prev is also maintained.
20106 * Usage for LRU is measured by the time the put_block() is done. The second
20107 * parameter to put_block() can violate the LRU order and put a block on the
20108 * front of the list, if it will probably not be needed soon. If a block
20109 * is modified, the modifying routine must set b_dirt to DIRTY, so the block
20110 * will eventually be rewritten to the disk.
20111 */
20112
20113 #include <sys/dir.h> /* need struct direct */
20114
.Ep 276 src/fs/buf.h
20115 EXTERN struct buf {
20116 /* Data portion of the buffer. */
20117 union {
20118 char b__data[BLOCK_SIZE]; /* ordinary user data */
20119 struct direct b__dir[NR_DIR_ENTRIES]; /* directory block */
20120 zone1_t b__v1_ind[V1_INDIRECTS]; /* V1 indirect block */
20121 zone_t b__v2_ind[V2_INDIRECTS]; /* V2 indirect block */
20122 d1_inode b__v1_ino[V1_INODES_PER_BLOCK]; /* V1 inode block */
20123 d2_inode b__v2_ino[V2_INODES_PER_BLOCK]; /* V2 inode block */
20124 bitchunk_t b__bitmap[BITMAP_CHUNKS]; /* bit map block */
20125 } b;
20126
20127 /* Header portion of the buffer. */
20128 struct buf *b_next; /* used to link all free bufs in a chain */
20129 struct buf *b_prev; /* used to link all free bufs the other way */
20130 struct buf *b_hash; /* used to link bufs on hash chains */
20131 block_t b_blocknr; /* block number of its (minor) device */
20132 dev_t b_dev; /* major | minor device where block resides */
20133 char b_dirt; /* CLEAN or DIRTY */
20134 char b_count; /* number of users of this buffer */
20135 } buf[NR_BUFS];
20136
20137 /* A block is free if b_dev == NO_DEV. */
20138
20139 #define NIL_BUF ((struct buf *) 0) /* indicates absence of a buffer */
20140
20141 /* These defs make it possible to use to bp->b_data instead of bp->b.b__data */
20142 #define b_data b.b__data
20143 #define b_dir b.b__dir
20144 #define b_v1_ind b.b__v1_ind
20145 #define b_v2_ind b.b__v2_ind
20146 #define b_v1_ino b.b__v1_ino
20147 #define b_v2_ino b.b__v2_ino
20148 #define b_bitmap b.b__bitmap
20149
20150 EXTERN struct buf *buf_hash[NR_BUF_HASH]; /* the buffer hash table */
20151
20152 EXTERN struct buf *front; /* points to least recently used free block */
20153 EXTERN struct buf *rear; /* points to most recently used free block */
20154 EXTERN int bufs_in_use; /* # bufs currently in use (not on free list)*/
20155
20156 /* When a block is released, the type of usage is passed to put_block(). */
20157 #define WRITE_IMMED 0100 /* block should be written to disk now */
20158 #define ONE_SHOT 0200 /* set if block not likely to be needed soon */
20159
20160 #define INODE_BLOCK (0 + MAYBE_WRITE_IMMED) /* inode block */
20161 #define DIRECTORY_BLOCK (1 + MAYBE_WRITE_IMMED) /* directory block */
20162 #define INDIRECT_BLOCK (2 + MAYBE_WRITE_IMMED) /* pointer block */
20163 #define MAP_BLOCK (3 + MAYBE_WRITE_IMMED) /* bit map */
20164 #define ZUPER_BLOCK (4 + WRITE_IMMED + ONE_SHOT) /* super block */
20165 #define FULL_DATA_BLOCK 5 /* data, fully used */
20166 #define PARTIAL_DATA_BLOCK 6 /* data, partly used*/
20167
20168 #define HASH_MASK (NR_BUF_HASH - 1) /* mask for hashing block numbers */
.Op 277 src/fs/dev.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/dev.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20200 /* Device table. This table is indexed by major device number. It provides
20201 * the link between major device numbers and the routines that process them.
20202 */
20203
20204 typedef _PROTOTYPE (void (*dmap_t), (int task, message *m_ptr) );
20205
20206 extern struct dmap {
20207 dmap_t dmap_open;
20208 dmap_t dmap_rw;
20209 dmap_t dmap_close;
20210 int dmap_task;
20211 } dmap[];
20212
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/file.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20300 /* This is the filp table. It is an intermediary between file descriptors and
20301 * inodes. A slot is free if filp_count == 0.
20302 */
20303
20304 EXTERN struct filp {
20305 mode_t filp_mode; /* RW bits, telling how file is opened */
20306 int filp_flags; /* flags from open and fcntl */
20307 int filp_count; /* how many file descriptors share this slot?*/
20308 struct inode *filp_ino; /* pointer to the inode */
20309 off_t filp_pos; /* file position */
20310 } filp[NR_FILPS];
20311
20312 #define FILP_CLOSED 0 /* filp_mode: associated device closed */
20313
20314 #define NIL_FILP (struct filp *) 0 /* indicates absence of a filp slot */
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/lock.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20400 /* This is the file locking table. Like the filp table, it points to the
20401 * inode table, however, in this case to achieve advisory locking.
20402 */
20403 EXTERN struct file_lock {
20404 short lock_type; /* F_RDLOCK or F_WRLOCK; 0 means unused slot */
20405 pid_t lock_pid; /* pid of the process holding the lock */
20406 struct inode *lock_inode; /* pointer to the inode locked */
20407 off_t lock_first; /* offset of first byte locked */
20408 off_t lock_last; /* offset of last byte locked */
20409 } file_lock[NR_LOCKS];
.Ep 278 src/fs/inode.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/inode.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20500 /* Inode table. This table holds inodes that are currently in use. In some
20501 * cases they have been opened by an open() or creat() system call, in other
20502 * cases the file system itself needs the inode for one reason or another,
20503 * such as to search a directory for a path name.
20504 * The first part of the struct holds fields that are present on the
20505 * disk; the second part holds fields not present on the disk.
20506 * The disk inode part is also declared in "type.h" as 'd1_inode' for V1
20507 * file systems and 'd2_inode' for V2 file systems.
20508 */
20509
20510 EXTERN struct inode {
20511 mode_t i_mode; /* file type, protection, etc. */
20512 nlink_t i_nlinks; /* how many links to this file */
20513 uid_t i_uid; /* user id of the file's owner */
20514 gid_t i_gid; /* group number */
20515 off_t i_size; /* current file size in bytes */
20516 time_t i_atime; /* time of last access (V2 only) */
20517 time_t i_mtime; /* when was file data last changed */
20518 time_t i_ctime; /* when was inode itself changed (V2 only)*/
20519 zone_t i_zone[V2_NR_TZONES]; /* zone numbers for direct, ind, and dbl ind */
20520
20521 /* The following items are not present on the disk. */
20522 dev_t i_dev; /* which device is the inode on */
20523 ino_t i_num; /* inode number on its (minor) device */
20524 int i_count; /* # times inode used; 0 means slot is free */
20525 int i_ndzones; /* # direct zones (Vx_NR_DZONES) */
20526 int i_nindirs; /* # indirect zones per indirect block */
20527 struct super_block *i_sp; /* pointer to super block for inode's device */
20528 char i_dirt; /* CLEAN or DIRTY */
20529 char i_pipe; /* set to I_PIPE if pipe */
20530 char i_mount; /* this bit is set if file mounted on */
20531 char i_seek; /* set on LSEEK, cleared on READ/WRITE */
20532 char i_update; /* the ATIME, CTIME, and MTIME bits are here */
20533 } inode[NR_INODES];
20534
20535
20536 #define NIL_INODE (struct inode *) 0 /* indicates absence of inode slot */
20537
20538 /* Field values. Note that CLEAN and DIRTY are defined in "const.h" */
20539 #define NO_PIPE 0 /* i_pipe is NO_PIPE if inode is not a pipe */
20540 #define I_PIPE 1 /* i_pipe is I_PIPE if inode is a pipe */
20541 #define NO_MOUNT 0 /* i_mount is NO_MOUNT if file not mounted on*/
20542 #define I_MOUNT 1 /* i_mount is I_MOUNT if file mounted on */
20543 #define NO_SEEK 0 /* i_seek = NO_SEEK if last op was not SEEK */
20544 #define ISEEK 1 /* i_seek = ISEEK if last op was SEEK */
.Op 279 src/fs/param.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/param.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20600 /* The following names are synonyms for the variables in the input message. */
20601 #define acc_time m.m2_l1
20602 #define addr m.m1_i3
20603 #define buffer m.m1_p1
20604 #define child m.m1_i2
20605 #define co_mode m.m1_i1
20606 #define eff_grp_id m.m1_i3
20607 #define eff_user_id m.m1_i3
20608 #define erki m.m1_p1
20609 #define fd m.m1_i1
20610 #define fd2 m.m1_i2
20611 #define ioflags m.m1_i3
20612 #define group m.m1_i3
20613 #define real_grp_id m.m1_i2
20614 #define ls_fd m.m2_i1
20615 #define mk_mode m.m1_i2
20616 #define mode m.m3_i2
20617 #define c_mode m.m1_i3
20618 #define c_name m.m1_p1
20619 #define name m.m3_p1
20620 #define name1 m.m1_p1
20621 #define name2 m.m1_p2
20622 #define name_length m.m3_i1
20623 #define name1_length m.m1_i1
20624 #define name2_length m.m1_i2
20625 #define nbytes m.m1_i2
20626 #define offset m.m2_l1
20627 #define owner m.m1_i2
20628 #define parent m.m1_i1
20629 #define pathname m.m3_ca1
20630 #define pid m.m1_i3
20631 #define pro m.m1_i1
20632 #define rd_only m.m1_i3
20633 #define real_user_id m.m1_i2
20634 #define request m.m1_i2
20635 #define sig m.m1_i2
20636 #define slot1 m.m1_i1
20637 #define tp m.m2_l1
20638 #define utime_actime m.m2_l1
20639 #define utime_modtime m.m2_l2
20640 #define utime_file m.m2_p1
20641 #define utime_length m.m2_i1
20642 #define whence m.m2_i2
20643
20644 /* The following names are synonyms for the variables in the output message. */
20645 #define reply_type m1.m_type
20646 #define reply_l1 m1.m2_l1
20647 #define reply_i1 m1.m1_i1
20648 #define reply_i2 m1.m1_i2
20649 #define reply_t1 m1.m4_l1
20650 #define reply_t2 m1.m4_l2
20651 #define reply_t3 m1.m4_l3
20652 #define reply_t4 m1.m4_l4
20653 #define reply_t5 m1.m4_l5
.Ep 280 src/fs/super.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/super.h
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20700 /* Super block table. The root file system and every mounted file system
20701 * has an entry here. The entry holds information about the sizes of the bit
20702 * maps and inodes. The s_ninodes field gives the number of inodes available
20703 * for files and directories, including the root directory. Inode 0 is
20704 * on the disk, but not used. Thus s_ninodes = 4 means that 5 bits will be
20705 * used in the bit map, bit 0, which is always 1 and not used, and bits 1-4
20706 * for files and directories. The disk layout is:
20707 *
20708 * Item # blocks
20709 * boot block 1
20710 * super block 1
20711 * inode map s_imap_blocks
20712 * zone map s_zmap_blocks
20713 * inodes (s_ninodes + 'inodes per block' - 1)/'inodes per block'
20714 * unused whatever is needed to fill out the current zone
20715 * data zones (s_zones - s_firstdatazone) << s_log_zone_size
20716 *
20717 * A super_block slot is free if s_dev == NO_DEV.
20718 */
20719
20720
20721 EXTERN struct super_block {
20722 ino_t s_ninodes; /* # usable inodes on the minor device */
20723 zone1_t s_nzones; /* total device size, including bit maps etc */
20724 short s_imap_blocks; /* # of blocks used by inode bit map */
20725 short s_zmap_blocks; /* # of blocks used by zone bit map */
20726 zone1_t s_firstdatazone; /* number of first data zone */
20727 short s_log_zone_size; /* log2 of blocks/zone */
20728 off_t s_max_size; /* maximum file size on this device */
20729 short s_magic; /* magic number to recognize super-blocks */
20730 short s_pad; /* try to avoid compiler-dependent padding */
20731 zone_t s_zones; /* number of zones (replaces s_nzones in V2) */
20732
20733 /* The following items are only used when the super_block is in memory. */
20734 struct inode *s_isup; /* inode for root dir of mounted file sys */
20735 struct inode *s_imount; /* inode mounted on */
20736 unsigned s_inodes_per_block; /* precalculated from magic number */
20737 dev_t s_dev; /* whose super block is this? */
20738 int s_rd_only; /* set to 1 iff file sys mounted read only */
20739 int s_native; /* set to 1 iff not byte swapped file system */
20740 int s_version; /* file system version, zero means bad magic */
20741 int s_ndzones; /* # direct zones in an inode */
20742 int s_nindirs; /* # indirect zones per indirect block */
20743 bit_t s_isearch; /* inodes below this bit number are in use */
20744 bit_t s_zsearch; /* all zones below this bit number are in use*/
20745 } super_block[NR_SUPERS];
20746
20747 #define NIL_SUPER (struct super_block *) 0
20748 #define IMAP 0 /* operating on the inode bit map */
20749 #define ZMAP 1 /* operating on the zone bit map */
.Op 281 src/fs/table.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/table.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
20800 /* This file contains the table used to map system call numbers onto the
20801 * routines that perform them.
20802 */
20803
20804 #define _TABLE
20805
20806 #include "fs.h"
20807 #include <minix/callnr.h>
20808 #include <minix/com.h>
20809 #include "buf.h"
20810 #include "dev.h"
20811 #include "file.h"
20812 #include "fproc.h"
20813 #include "inode.h"
20814 #include "lock.h"
20815 #include "super.h"
20816
20817 PUBLIC _PROTOTYPE (int (*call_vector[NCALLS]), (void) ) = {
20818 no_sys, /* 0 = unused */
20819 do_exit, /* 1 = exit */
20820 do_fork, /* 2 = fork */
20821 do_read, /* 3 = read */
20822 do_write, /* 4 = write */
20823 do_open, /* 5 = open */
20824 do_close, /* 6 = close */
20825 no_sys, /* 7 = wait */
20826 do_creat, /* 8 = creat */
20827 do_link, /* 9 = link */
20828 do_unlink, /* 10 = unlink */
20829 no_sys, /* 11 = waitpid */
20830 do_chdir, /* 12 = chdir */
20831 do_time, /* 13 = time */
20832 do_mknod, /* 14 = mknod */
20833 do_chmod, /* 15 = chmod */
20834 do_chown, /* 16 = chown */
20835 no_sys, /* 17 = break */
20836 do_stat, /* 18 = stat */
20837 do_lseek, /* 19 = lseek */
20838 no_sys, /* 20 = getpid */
20839 do_mount, /* 21 = mount */
20840 do_umount, /* 22 = umount */
20841 do_set, /* 23 = setuid */
20842 no_sys, /* 24 = getuid */
20843 do_stime, /* 25 = stime */
20844 no_sys, /* 26 = ptrace */
20845 no_sys, /* 27 = alarm */
20846 do_fstat, /* 28 = fstat */
20847 no_sys, /* 29 = pause */
20848 do_utime, /* 30 = utime */
20849 no_sys, /* 31 = (stty) */
20850 no_sys, /* 32 = (gtty) */
20851 do_access, /* 33 = access */
20852 no_sys, /* 34 = (nice) */
20853 no_sys, /* 35 = (ftime) */
20854 do_sync, /* 36 = sync */
.Ep 282 src/fs/table.c
20855 no_sys, /* 37 = kill */
20856 do_rename, /* 38 = rename */
20857 do_mkdir, /* 39 = mkdir */
20858 do_unlink, /* 40 = rmdir */
20859 do_dup, /* 41 = dup */
20860 do_pipe, /* 42 = pipe */
20861 do_tims, /* 43 = times */
20862 no_sys, /* 44 = (prof) */
20863 no_sys, /* 45 = unused */
20864 do_set, /* 46 = setgid */
20865 no_sys, /* 47 = getgid */
20866 no_sys, /* 48 = (signal)*/
20867 no_sys, /* 49 = unused */
20868 no_sys, /* 50 = unused */
20869 no_sys, /* 51 = (acct) */
20870 no_sys, /* 52 = (phys) */
20871 no_sys, /* 53 = (lock) */
20872 do_ioctl, /* 54 = ioctl */
20873 do_fcntl, /* 55 = fcntl */
20874 no_sys, /* 56 = (mpx) */
20875 no_sys, /* 57 = unused */
20876 no_sys, /* 58 = unused */
20877 do_exec, /* 59 = execve */
20878 do_umask, /* 60 = umask */
20879 do_chroot, /* 61 = chroot */
20880 do_setsid, /* 62 = setsid */
20881 no_sys, /* 63 = getpgrp */
20882
20883 no_sys, /* 64 = KSIG: signals originating in the kernel */
20884 do_unpause, /* 65 = UNPAUSE */
20885 no_sys, /* 66 = unused */
20886 do_revive, /* 67 = REVIVE */
20887 no_sys, /* 68 = TASK_REPLY */
20888 no_sys, /* 69 = unused */
20889 no_sys, /* 70 = unused */
20890 no_sys, /* 71 = SIGACTION */
20891 no_sys, /* 72 = SIGSUSPEND */
20892 no_sys, /* 73 = SIGPENDING */
20893 no_sys, /* 74 = SIGPROCMASK */
20894 no_sys, /* 75 = SIGRETURN */
20895 no_sys, /* 76 = REBOOT */
20896 };
20897
20898
20899 /* Some devices may or may not be there in the next table. */
20900 #define DT(enable, open, rw, close, task)
20901 { (enable ? (open) : no_dev), (enable ? (rw) : no_dev),
20902 (enable ? (close) : no_dev), (enable ? (task) : 0) },
20903
20904 /* The order of the entries here determines the mapping between major device
20905 * numbers and tasks. The first entry (major device 0) is not used. The
20906 * next entry is major device 1, etc. Character and block devices can be
20907 * intermixed at random. If this ordering is changed, the devices in
20908 * <include/minix/boot.h> must be changed to correspond to the new values.
20909 * Note that the major device numbers used in /dev are NOT the same as the
20910 * task numbers used inside the kernel (as defined in <include/minix/com.h>).
20911 * Also note that if /dev/mem is changed from 1, NULL_MAJOR must be changed
20912 * in <include/minix/com.h>.
20913 */
20914 PUBLIC struct dmap dmap[] = {
.Op 283 src/fs/table.c
20915 /* ? Open Read/Write Close Task # Device File
20916 - ---- ---------- ----- ------- ------ ---- */
20917 DT(1, no_dev, no_dev, no_dev, 0) /* 0 = not used */
20918 DT(1, dev_opcl, call_task, dev_opcl, MEM) /* 1 = /dev/mem */
20919 DT(1, dev_opcl, call_task, dev_opcl, FLOPPY) /* 2 = /dev/fd0 */
20920 DT(ENABLE_WINI,
20921 dev_opcl, call_task, dev_opcl, WINCHESTER) /* 3 = /dev/hd0 */
20922 DT(1, tty_open, call_task, dev_opcl, TTY) /* 4 = /dev/tty00 */
20923 DT(1, ctty_open, call_ctty, ctty_close, TTY) /* 5 = /dev/tty */
20924 DT(1, dev_opcl, call_task, dev_opcl, PRINTER) /* 6 = /dev/lp */
20925
20926 #if (MACHINE == IBM_PC)
20927 DT(ENABLE_NETWORKING,
20928 net_open, call_task, dev_opcl, INET_PROC_NR)/* 7 = /dev/ip */
20929 DT(ENABLE_CDROM,
20930 dev_opcl, call_task, dev_opcl, CDROM) /* 8 = /dev/cd0 */
20931 DT(0, 0, 0, 0, 0) /* 9 = not used */
20932 DT(ENABLE_SCSI,
20933 dev_opcl, call_task, dev_opcl, SCSI) /*10 = /dev/sd0 */
20934 DT(0, 0, 0, 0, 0) /*11 = not used */
20935 DT(0, 0, 0, 0, 0) /*12 = not used */
20936 DT(ENABLE_AUDIO,
20937 dev_opcl, call_task, dev_opcl, AUDIO) /*13 = /dev/audio */
20938 DT(ENABLE_AUDIO,
20939 dev_opcl, call_task, dev_opcl, MIXER) /*14 = /dev/mixer */
20940 #endif /* IBM_PC */
20941
20942 #if (MACHINE == ATARI)
20943 DT(ENABLE_SCSI,
20944 dev_opcl, call_task, dev_opcl, SCSI) /* 7 = /dev/hdscsi0 */
20945 #endif
20946 };
20947
20948 PUBLIC int max_major = sizeof(dmap)/sizeof(struct dmap);
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
src/fs/cache.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
21000 /* The file system maintains a buffer cache to reduce the number of disk
21001 * accesses needed. Whenever a read or write to the disk is done, a check is
21002 * first made to see if the block is in the cache. This file manages the
21003 * cache.
21004 *
21005 * The entry points into this file are:
21006 * get_block: request to fetch a block for reading or writing from cache
21007 * put_block: return a block previously requested with get_block
21008 * alloc_zone: allocate a new zone (to increase the length of a file)
21009 * free_zone: release a zone (when a file is removed)
21010 * rw_block: read or write a block from the disk itself
21011 * invalidate: remove all the cache blocks on some device
21012 */
21013
21014 #include "fs.h"
21015 #include <minix/com.h>
21016 #include <minix/boot.h>
21017 #include "buf.h"
21018 #include "file.h"
21019 #include "fproc.h"
.Ep 284 src/fs/cache.c
21020 #include "super.h"
21021
21022 FORWARD _PROTOTYPE( void rm_lru, (struct buf *bp) );
21023
21024 /*===========================================================================*
21025 * get_block *
21026 *===========================================================================*/
21027 PUBLIC struct buf *get_block(dev, block, only_search)
21028 register dev_t dev; /* on which device is the block? */
21029 register block_t block; /* which block is wanted? */
21030 int only_search; /* if NO_READ, don't read, else act normal */
21031 {
21032 /* Check to see if the requested block is in the block cache. If so, return
21033 * a pointer to it. If not, evict some other block and fetch it (unless
21034 * 'only_search' is 1). All the blocks in the cache that are not in use
21035 * are linked together in a chain, with 'front' pointing to the least recently
21036 * used block and 'rear' to the most recently used block. If 'only_search' is
21037 * 1, the block being requested will be overwritten in its entirety, so it is
21038 * only necessary to see if it is in the cache; if it is not, any free buffer
21039 * will do. It is not necessary to actually read the block in from disk.
21040 * If 'only_search' is PREFETCH, the block need not be read from the disk,
21041 * and the device is not to be marked on the block, so callers can tell if
21042 * the block returned is valid.
21043 * In addition to the LRU chain, there is also a hash chain to link together
21044 * blocks whose block numbers end with the same bit strings, for fast lookup.
21045 */
21046
21047 int b;
21048 register struct buf *bp, *prev_ptr;
21049
21050 /* Search the hash chain for (dev, block). Do_read() can use
21051 * get_block(NO_DEV ...) to get an unnamed block to fill with zeros when
21052 * someone wants to read from a hole in a file, in which case this search
21053 * is skipped
21054 */
21055 if (dev != NO_DEV) {
21056 b = (int) block & HASH_MASK;
21057 bp = buf_hash[b];
21058 while (bp != NIL_BUF) {
21059 if (bp->b_blocknr == block && bp->b_dev == dev) {
21060 /* Block needed has been found. */
21061 if (bp->b_count == 0) rm_lru(bp);
21062 bp->b_count++; /* record that block is in use */
21063 return(bp);
21064 } else {
21065 /* This block is not the one sought. */
21066 bp = bp->b_hash; /* move to next block on hash chain */
21067 }
21068 }
21069 }
21070
21071 /* Desired block is not on available chain. Take oldest block ('front'). */
21072 if ((bp = front) == NIL_BUF) panic("all buffers in use", NR_BUFS);
21073 rm_lru(bp);
21074
21075 /* Remove the block that was just taken from its hash chain. */
21076 b = (int) bp->b_blocknr & HASH_MASK;
21077 prev_ptr = buf_hash[b];
21078 if (prev_ptr == bp) {
21079 buf_hash[b] = bp->b_hash;
.Op 285 src/fs/cache.c
21080 } else {
21081 /* The block just taken is not on the front of its hash chain. */
21082 while (prev_ptr->b_hash != NIL_BUF)
21083 if (prev_ptr->b_hash == bp) {
21084 prev_ptr->b_hash = bp->b_hash; /* found it */
21085 break;
21086 } else {
21087 prev_ptr = prev_ptr->b_hash; /* keep looking */
21088 }
21089 }
21090
21091 /* If the block taken is dirty, make it clean by writing it to the disk.
21092 * Avoid hysteresis by flushing all other dirty blocks for the same device.
21093 */
21094 if (bp->b_dev != NO_DEV) {
21095 if (bp->b_dirt == DIRTY) flushall(bp->b_dev);
21096 }
21097
21098 /* Fill in block's parameters and add it to the hash chain where it goes. */
21099 bp->b_dev = dev; /* fill in device number */
21100 bp->b_blocknr = block; /* fill in block number */
21101 bp->b_count++; /* record that block is being used */
21102 b = (int) bp->b_blocknr & HASH_MASK;
21103 bp->b_hash = buf_hash[b];
21104 buf_hash[b] = bp; /* add to hash list */
21105
21106 /* Go get the requested block unless searching or prefetching. */
21107 if (dev != NO_DEV) {
21108 if (only_search == PREFETCH) bp->b_dev = NO_DEV;
21109 else
21110 if (only_search == NORMAL) rw_block(bp, READING);
21111 }
21112 return(bp); /* return the newly acquired block */
21113 }
21116 /*===========================================================================*
21117 * put_block *
21118 *===========================================================================*/
21119 PUBLIC void put_block(bp, block_type)
21120 register struct buf *bp; /* pointer to the buffer to be released */
21121 int block_type; /* INODE_BLOCK, DIRECTORY_BLOCK, or whatever */
21122 {
21123 /* Return a block to the list of available blocks. Depending on 'block_type'
21124 * it may be put on the front or rear of the LRU chain. Blocks that are
21125 * expected to be needed again shortly (e.g., partially full data blocks)
21126 * go on the rear; blocks that are unlikely to be needed again shortly
21127 * (e.g., full data blocks) go on the front. Blocks whose loss can hurt
21128 * the integrity of the file system (e.g., inode blocks) are written to
21129 * disk immediately if they are dirty.
21130 */
21131
21132 if (bp == NIL_BUF) return; /* it is easier to check here than in caller */
21133
21134 bp->b_count--; /* there is one use fewer now */
21135 if (bp->b_count != 0) return; /* block is still in use */
21136
21137 bufs_in_use--; /* one fewer block buffers in use */
21138
21139 /* Put this block back on the LRU chain. If the ONE_SHOT bit is set in
.Ep 286 src/fs/cache.c
21140 * 'block_type', the block is not likely to be needed again shortly, so put
21141 * it on the front of the LRU chain where it will be the first one to be
21142 * taken when a free buffer is needed later.
21143 */
21144 if (block_type & ONE_SHOT) {
21145 /* Block probably won't be needed quickly. Put it on front of chain.
21146 * It will be the next block to be evicted from the cache.
21147 */
21148 bp->b_prev = NIL_BUF;
21149 bp->b_next = front;
21150 if (front == NIL_BUF)
21151 rear = bp; /* LRU chain was empty */
21152 else
21153 front->b_prev = bp;
21154 front = bp;
21155 } else {
21156 /* Block probably will be needed quickly. Put it on rear of chain.
21157 * It will not be evicted from the cache for a long time.
21158 */
21159 bp->b_prev = rear;
21160 bp->b_next = NIL_BUF;
21161 if (rear == NIL_BUF)
21162 front = bp;
21163 else
21164 rear->b_next = bp;
21165 rear = bp;
21166 }
21167
21168 /* Some blocks are so important (e.g., inodes, indirect blocks) that they
21169 * should be written to the disk immediately to avoid messing up the file
21170 * system in the event of a crash.
21171 */
21172 if ((block_type & WRITE_IMMED) && bp->b_dirt==DIRTY && bp->b_dev != NO_DEV)
21173 rw_block(bp, WRITING);
21174 }
21177 /*===========================================================================*
21178 * alloc_zone *
21179 *===========================================================================*/
21180 PUBLIC zone_t alloc_zone(dev, z)
21181 dev_t dev; /* device where zone wanted */
21182 zone_t z; /* try to allocate new zone near this one */
21183 {
21184 /* Allocate a new zone on the indicated device and return its number. */
21185
21186 int major, minor;
21187 bit_t b, bit;
21188 struct super_block *sp;
21189
21190 /* Note that the routine alloc_bit() returns 1 for the lowest possible