signal.c
上传用户:lgb322
上传日期:2013-02-24
资源大小:30529k
文件大小:18k
- /*
- * Architecture-specific signal handling support.
- *
- * Copyright (C) 1999-2001 Hewlett-Packard Co
- * David Mosberger-Tang <davidm@hpl.hp.com>
- *
- * Derived from i386 and Alpha versions.
- */
- #include <linux/config.h>
- #include <linux/errno.h>
- #include <linux/kernel.h>
- #include <linux/mm.h>
- #include <linux/ptrace.h>
- #include <linux/sched.h>
- #include <linux/signal.h>
- #include <linux/smp.h>
- #include <linux/smp_lock.h>
- #include <linux/stddef.h>
- #include <linux/unistd.h>
- #include <linux/wait.h>
- #include <asm/ia32.h>
- #include <asm/uaccess.h>
- #include <asm/rse.h>
- #include <asm/sigcontext.h>
- #include "sigframe.h"
- #define DEBUG_SIG 0
- #define STACK_ALIGN 16 /* minimal alignment for stack pointer */
- #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
- #if _NSIG_WORDS > 1
- # define PUT_SIGSET(k,u) __copy_to_user((u)->sig, (k)->sig, sizeof(sigset_t))
- # define GET_SIGSET(k,u) __copy_from_user((k)->sig, (u)->sig, sizeof(sigset_t))
- #else
- # define PUT_SIGSET(k,u) __put_user((k)->sig[0], &(u)->sig[0])
- # define GET_SIGSET(k,u) __get_user((k)->sig[0], &(u)->sig[0])
- #endif
- extern long ia64_do_signal (sigset_t *, struct sigscratch *, long); /* forward decl */
- long
- ia64_rt_sigsuspend (sigset_t *uset, size_t sigsetsize, struct sigscratch *scr)
- {
- sigset_t oldset, set;
- /* XXX: Don't preclude handling different sized sigset_t's. */
- if (sigsetsize != sizeof(sigset_t))
- return -EINVAL;
- if (!access_ok(VERIFY_READ, uset, sigsetsize))
- return -EFAULT;
- if (GET_SIGSET(&set, uset))
- return -EFAULT;
- sigdelsetmask(&set, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- {
- oldset = current->blocked;
- current->blocked = set;
- recalc_sigpending(current);
- }
- spin_unlock_irq(¤t->sigmask_lock);
- /*
- * The return below usually returns to the signal handler. We need to
- * pre-set the correct error code here to ensure that the right values
- * get saved in sigcontext by ia64_do_signal.
- */
- scr->pt.r8 = EINTR;
- scr->pt.r10 = -1;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (ia64_do_signal(&oldset, scr, 1))
- return -EINTR;
- }
- }
- asmlinkage long
- sys_sigaltstack (const stack_t *uss, stack_t *uoss, long arg2, long arg3, long arg4,
- long arg5, long arg6, long arg7, long stack)
- {
- struct pt_regs *pt = (struct pt_regs *) &stack;
- return do_sigaltstack(uss, uoss, pt->r12);
- }
- static long
- restore_sigcontext (struct sigcontext *sc, struct sigscratch *scr)
- {
- unsigned long ip, flags, nat, um, cfm;
- long err;
- /* restore scratch that always needs gets updated during signal delivery: */
- err = __get_user(flags, &sc->sc_flags);
- err |= __get_user(nat, &sc->sc_nat);
- err |= __get_user(ip, &sc->sc_ip); /* instruction pointer */
- err |= __get_user(cfm, &sc->sc_cfm);
- err |= __get_user(um, &sc->sc_um); /* user mask */
- err |= __get_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
- err |= __get_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);
- err |= __get_user(scr->pt.ar_unat, &sc->sc_ar_unat);
- err |= __get_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr);
- err |= __get_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
- err |= __get_user(scr->pt.pr, &sc->sc_pr); /* predicates */
- err |= __get_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
- err |= __get_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
- err |= __get_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
- err |= __copy_from_user(&scr->pt.r1, &sc->sc_gr[1], 3*8); /* r1-r3 */
- err |= __copy_from_user(&scr->pt.r8, &sc->sc_gr[8], 4*8); /* r8-r11 */
- err |= __copy_from_user(&scr->pt.r12, &sc->sc_gr[12], 4*8); /* r12-r15 */
- err |= __copy_from_user(&scr->pt.r16, &sc->sc_gr[16], 16*8); /* r16-r31 */
- scr->pt.cr_ifs = cfm | (1UL << 63);
- /* establish new instruction pointer: */
- scr->pt.cr_iip = ip & ~0x3UL;
- ia64_psr(&scr->pt)->ri = ip & 0x3;
- scr->pt.cr_ipsr = (scr->pt.cr_ipsr & ~IA64_PSR_UM) | (um & IA64_PSR_UM);
- scr->scratch_unat = ia64_put_scratch_nat_bits(&scr->pt, nat);
- if ((flags & IA64_SC_FLAG_FPH_VALID) != 0) {
- struct ia64_psr *psr = ia64_psr(&scr->pt);
- __copy_from_user(current->thread.fph, &sc->sc_fr[32], 96*16);
- psr->mfh = 0; /* drop signal handler's fph contents... */
- if (!psr->dfh)
- __ia64_load_fpu(current->thread.fph);
- }
- return err;
- }
- int
- copy_siginfo_to_user (siginfo_t *to, siginfo_t *from)
- {
- if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t)))
- return -EFAULT;
- if (from->si_code < 0)
- return __copy_to_user(to, from, sizeof(siginfo_t));
- else {
- int err;
- /*
- * If you change siginfo_t structure, please be sure
- * this code is fixed accordingly. It should never
- * copy any pad contained in the structure to avoid
- * security leaks, but must copy the generic 3 ints
- * plus the relevant union member.
- */
- err = __put_user(from->si_signo, &to->si_signo);
- err |= __put_user(from->si_errno, &to->si_errno);
- err |= __put_user((short)from->si_code, &to->si_code);
- switch (from->si_code >> 16) {
- case __SI_FAULT >> 16:
- err |= __put_user(from->si_isr, &to->si_isr);
- case __SI_POLL >> 16:
- err |= __put_user(from->si_addr, &to->si_addr);
- err |= __put_user(from->si_imm, &to->si_imm);
- break;
- case __SI_CHLD >> 16:
- err |= __put_user(from->si_utime, &to->si_utime);
- err |= __put_user(from->si_stime, &to->si_stime);
- err |= __put_user(from->si_status, &to->si_status);
- case __SI_PROF >> 16:
- err |= __put_user(from->si_uid, &to->si_uid);
- err |= __put_user(from->si_pid, &to->si_pid);
- err |= __put_user(from->si_pfm_ovfl, &to->si_pfm_ovfl);
- break;
- default:
- err |= __put_user(from->si_uid, &to->si_uid);
- err |= __put_user(from->si_pid, &to->si_pid);
- break;
- /* case __SI_RT: This is not generated by the kernel as of now. */
- }
- return err;
- }
- }
- int
- copy_siginfo_from_user (siginfo_t *to, siginfo_t *from)
- {
- if (!access_ok(VERIFY_READ, from, sizeof(siginfo_t)))
- return -EFAULT;
- if (__copy_from_user(to, from, sizeof(siginfo_t)) != 0)
- return -EFAULT;
- if (SI_FROMUSER(to))
- return 0;
- to->si_code &= ~__SI_MASK;
- if (to->si_code != 0) {
- switch (to->si_signo) {
- case SIGILL: case SIGFPE: case SIGSEGV: case SIGBUS: case SIGTRAP:
- to->si_code |= __SI_FAULT;
- break;
- case SIGCHLD:
- to->si_code |= __SI_CHLD;
- break;
- case SIGPOLL:
- to->si_code |= __SI_POLL;
- break;
- case SIGPROF:
- to->si_code |= __SI_PROF;
- break;
- default:
- break;
- }
- }
- return 0;
- }
- long
- ia64_rt_sigreturn (struct sigscratch *scr)
- {
- extern char ia64_strace_leave_kernel, ia64_leave_kernel;
- struct sigcontext *sc;
- struct siginfo si;
- sigset_t set;
- long retval;
- sc = &((struct sigframe *) (scr->pt.r12 + 16))->sc;
- /*
- * When we return to the previously executing context, r8 and r10 have already
- * been setup the way we want them. Indeed, if the signal wasn't delivered while
- * in a system call, we must not touch r8 or r10 as otherwise user-level state
- * could be corrupted.
- */
- retval = (long) &ia64_leave_kernel;
- if (current->ptrace & PT_TRACESYS)
- /*
- * strace expects to be notified after sigreturn returns even though the
- * context to which we return may not be in the middle of a syscall.
- * Thus, the return-value that strace displays for sigreturn is
- * meaningless.
- */
- retval = (long) &ia64_strace_leave_kernel;
- if (!access_ok(VERIFY_READ, sc, sizeof(*sc)))
- goto give_sigsegv;
- if (GET_SIGSET(&set, &sc->sc_mask))
- goto give_sigsegv;
- sigdelsetmask(&set, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- {
- current->blocked = set;
- recalc_sigpending(current);
- }
- spin_unlock_irq(¤t->sigmask_lock);
- if (restore_sigcontext(sc, scr))
- goto give_sigsegv;
- #if DEBUG_SIG
- printk("SIG return (%s:%d): sp=%lx ip=%lxn",
- current->comm, current->pid, scr->pt.r12, scr->pt.cr_iip);
- #endif
- /*
- * It is more difficult to avoid calling this function than to
- * call it and ignore errors.
- */
- do_sigaltstack(&sc->sc_stack, 0, scr->pt.r12);
- return retval;
- give_sigsegv:
- si.si_signo = SIGSEGV;
- si.si_errno = 0;
- si.si_code = SI_KERNEL;
- si.si_pid = current->pid;
- si.si_uid = current->uid;
- si.si_addr = sc;
- force_sig_info(SIGSEGV, &si, current);
- return retval;
- }
- /*
- * This does just the minimum required setup of sigcontext.
- * Specifically, it only installs data that is either not knowable at
- * the user-level or that gets modified before execution in the
- * trampoline starts. Everything else is done at the user-level.
- */
- static long
- setup_sigcontext (struct sigcontext *sc, sigset_t *mask, struct sigscratch *scr)
- {
- unsigned long flags = 0, ifs, nat;
- long err;
- ifs = scr->pt.cr_ifs;
- if (on_sig_stack((unsigned long) sc))
- flags |= IA64_SC_FLAG_ONSTACK;
- if ((ifs & (1UL << 63)) == 0) {
- /* if cr_ifs isn't valid, we got here through a syscall */
- flags |= IA64_SC_FLAG_IN_SYSCALL;
- }
- ia64_flush_fph(current);
- if ((current->thread.flags & IA64_THREAD_FPH_VALID)) {
- flags |= IA64_SC_FLAG_FPH_VALID;
- __copy_to_user(&sc->sc_fr[32], current->thread.fph, 96*16);
- }
- /*
- * Note: sw->ar_unat is UNDEFINED unless the process is being
- * PTRACED. However, this is OK because the NaT bits of the
- * preserved registers (r4-r7) are never being looked at by
- * the signal handler (registers r4-r7 are used instead).
- */
- nat = ia64_get_scratch_nat_bits(&scr->pt, scr->scratch_unat);
- err = __put_user(flags, &sc->sc_flags);
- err |= __put_user(nat, &sc->sc_nat);
- err |= PUT_SIGSET(mask, &sc->sc_mask);
- err |= __put_user(scr->pt.cr_ipsr & IA64_PSR_UM, &sc->sc_um);
- err |= __put_user(scr->pt.ar_rsc, &sc->sc_ar_rsc);
- err |= __put_user(scr->pt.ar_ccv, &sc->sc_ar_ccv);
- err |= __put_user(scr->pt.ar_unat, &sc->sc_ar_unat); /* ar.unat */
- err |= __put_user(scr->pt.ar_fpsr, &sc->sc_ar_fpsr); /* ar.fpsr */
- err |= __put_user(scr->pt.ar_pfs, &sc->sc_ar_pfs);
- err |= __put_user(scr->pt.pr, &sc->sc_pr); /* predicates */
- err |= __put_user(scr->pt.b0, &sc->sc_br[0]); /* b0 (rp) */
- err |= __put_user(scr->pt.b6, &sc->sc_br[6]); /* b6 */
- err |= __put_user(scr->pt.b7, &sc->sc_br[7]); /* b7 */
- err |= __copy_to_user(&sc->sc_gr[1], &scr->pt.r1, 3*8); /* r1-r3 */
- err |= __copy_to_user(&sc->sc_gr[8], &scr->pt.r8, 4*8); /* r8-r11 */
- err |= __copy_to_user(&sc->sc_gr[12], &scr->pt.r12, 4*8); /* r12-r15 */
- err |= __copy_to_user(&sc->sc_gr[16], &scr->pt.r16, 16*8); /* r16-r31 */
- err |= __put_user(scr->pt.cr_iip + ia64_psr(&scr->pt)->ri, &sc->sc_ip);
- return err;
- }
- static long
- setup_frame (int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set,
- struct sigscratch *scr)
- {
- extern char ia64_sigtramp[], __start_gate_section[];
- unsigned long tramp_addr, new_rbs = 0;
- struct sigframe *frame;
- struct siginfo si;
- long err;
- frame = (void *) scr->pt.r12;
- tramp_addr = GATE_ADDR + (ia64_sigtramp - __start_gate_section);
- if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && !on_sig_stack((unsigned long) frame)) {
- new_rbs = (current->sas_ss_sp + sizeof(long) - 1) & ~(sizeof(long) - 1);
- frame = (void *) ((current->sas_ss_sp + current->sas_ss_size)
- & ~(STACK_ALIGN - 1));
- }
- frame = (void *) frame - ((sizeof(*frame) + STACK_ALIGN - 1) & ~(STACK_ALIGN - 1));
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
- goto give_sigsegv;
- err = __put_user(sig, &frame->arg0);
- err |= __put_user(&frame->info, &frame->arg1);
- err |= __put_user(&frame->sc, &frame->arg2);
- err |= __put_user(new_rbs, &frame->sc.sc_rbs_base);
- err |= __put_user(0, &frame->sc.sc_loadrs); /* initialize to zero */
- err |= __put_user(ka->sa.sa_handler, &frame->handler);
- err |= copy_siginfo_to_user(&frame->info, info);
- err |= __put_user(current->sas_ss_sp, &frame->sc.sc_stack.ss_sp);
- err |= __put_user(current->sas_ss_size, &frame->sc.sc_stack.ss_size);
- err |= __put_user(sas_ss_flags(scr->pt.r12), &frame->sc.sc_stack.ss_flags);
- err |= setup_sigcontext(&frame->sc, set, scr);
- if (err)
- goto give_sigsegv;
- scr->pt.r12 = (unsigned long) frame - 16; /* new stack pointer */
- scr->pt.ar_fpsr = FPSR_DEFAULT; /* reset fpsr for signal handler */
- scr->pt.cr_iip = tramp_addr;
- ia64_psr(&scr->pt)->ri = 0; /* start executing in first slot */
- /*
- * Note: this affects only the NaT bits of the scratch regs (the ones saved in
- * pt_regs), which is exactly what we want.
- */
- scr->scratch_unat = 0; /* ensure NaT bits of r12 is clear */
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sig=%d sp=%lx ip=%lx handler=%lxn",
- current->comm, current->pid, sig, scr->pt.r12, scr->pt.cr_iip, scr->pt.r3);
- #endif
- return 1;
- give_sigsegv:
- if (sig == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- si.si_signo = SIGSEGV;
- si.si_errno = 0;
- si.si_code = SI_KERNEL;
- si.si_pid = current->pid;
- si.si_uid = current->uid;
- si.si_addr = frame;
- force_sig_info(SIGSEGV, &si, current);
- return 0;
- }
- static long
- handle_signal (unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset,
- struct sigscratch *scr)
- {
- #ifdef CONFIG_IA32_SUPPORT
- if (IS_IA32_PROCESS(&scr->pt)) {
- /* send signal to IA-32 process */
- if (!ia32_setup_frame1(sig, ka, info, oldset, &scr->pt))
- return 0;
- } else
- #endif
- /* send signal to IA-64 process */
- if (!setup_frame(sig, ka, info, oldset, scr))
- return 0;
- if (ka->sa.sa_flags & SA_ONESHOT)
- ka->sa.sa_handler = SIG_DFL;
- if (!(ka->sa.sa_flags & SA_NODEFER)) {
- spin_lock_irq(¤t->sigmask_lock);
- {
- sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask);
- sigaddset(¤t->blocked, sig);
- recalc_sigpending(current);
- }
- spin_unlock_irq(¤t->sigmask_lock);
- }
- return 1;
- }
- /*
- * Note that `init' is a special process: it doesn't get signals it doesn't want to
- * handle. Thus you cannot kill init even with a SIGKILL even by mistake.
- */
- long
- ia64_do_signal (sigset_t *oldset, struct sigscratch *scr, long in_syscall)
- {
- struct signal_struct *sig;
- struct k_sigaction *ka;
- siginfo_t info;
- long restart = in_syscall;
- long errno = scr->pt.r8;
- /*
- * In the ia64_leave_kernel code path, we want the common case to go fast, which
- * is why we may in certain cases get here from kernel mode. Just return without
- * doing anything if so.
- */
- if (!user_mode(&scr->pt))
- return 0;
- if (!oldset)
- oldset = ¤t->blocked;
- #ifdef CONFIG_IA32_SUPPORT
- if (IS_IA32_PROCESS(&scr->pt)) {
- if (in_syscall) {
- if (errno >= 0)
- restart = 0;
- else
- errno = -errno;
- }
- } else
- #endif
- if (scr->pt.r10 != -1) {
- /*
- * A system calls has to be restarted only if one of the error codes
- * ERESTARTNOHAND, ERESTARTSYS, or ERESTARTNOINTR is returned. If r10
- * isn't -1 then r8 doesn't hold an error code and we don't need to
- * restart the syscall, so we can clear the "restart" flag here.
- */
- restart = 0;
- }
- for (;;) {
- unsigned long signr;
- spin_lock_irq(¤t->sigmask_lock);
- signr = dequeue_signal(¤t->blocked, &info);
- spin_unlock_irq(¤t->sigmask_lock);
- if (!signr)
- break;
- if ((current->ptrace & PT_PTRACED) && signr != SIGKILL) {
- /* Let the debugger run. */
- current->exit_code = signr;
- current->thread.siginfo = &info;
- current->state = TASK_STOPPED;
- notify_parent(current, SIGCHLD);
- schedule();
- signr = current->exit_code;
- current->thread.siginfo = 0;
- /* We're back. Did the debugger cancel the sig? */
- if (!signr)
- continue;
- current->exit_code = 0;
- /* The debugger continued. Ignore SIGSTOP. */
- if (signr == SIGSTOP)
- continue;
- /* Update the siginfo structure. Is this good? */
- if (signr != info.si_signo) {
- info.si_signo = signr;
- info.si_errno = 0;
- info.si_code = SI_USER;
- info.si_pid = current->p_pptr->pid;
- info.si_uid = current->p_pptr->uid;
- }
- /* If the (new) signal is now blocked, requeue it. */
- if (sigismember(¤t->blocked, signr)) {
- send_sig_info(signr, &info, current);
- continue;
- }
- }
- ka = ¤t->sig->action[signr - 1];
- if (ka->sa.sa_handler == SIG_IGN) {
- if (signr != SIGCHLD)
- continue;
- /* Check for SIGCHLD: it's special. */
- while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0)
- /* nothing */;
- continue;
- }
- if (ka->sa.sa_handler == SIG_DFL) {
- int exit_code = signr;
- /* Init gets no signals it doesn't want. */
- if (current->pid == 1)
- continue;
- switch (signr) {
- case SIGCONT: case SIGCHLD: case SIGWINCH:
- continue;
- case SIGTSTP: case SIGTTIN: case SIGTTOU:
- if (is_orphaned_pgrp(current->pgrp))
- continue;
- /* FALLTHRU */
- case SIGSTOP:
- current->state = TASK_STOPPED;
- current->exit_code = signr;
- sig = current->p_pptr->sig;
- if (sig && !(sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP))
- notify_parent(current, SIGCHLD);
- schedule();
- continue;
- case SIGQUIT: case SIGILL: case SIGTRAP:
- case SIGABRT: case SIGFPE: case SIGSEGV:
- case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ:
- if (do_coredump(signr, &scr->pt))
- exit_code |= 0x80;
- /* FALLTHRU */
- default:
- sigaddset(¤t->pending.signal, signr);
- recalc_sigpending(current);
- current->flags |= PF_SIGNALED;
- do_exit(exit_code);
- /* NOTREACHED */
- }
- }
- if (restart) {
- switch (errno) {
- case ERESTARTSYS:
- if ((ka->sa.sa_flags & SA_RESTART) == 0) {
- case ERESTARTNOHAND:
- #ifdef CONFIG_IA32_SUPPORT
- if (IS_IA32_PROCESS(&scr->pt))
- scr->pt.r8 = -EINTR;
- else
- #endif
- scr->pt.r8 = EINTR;
- /* note: scr->pt.r10 is already -1 */
- break;
- }
- case ERESTARTNOINTR:
- #ifdef CONFIG_IA32_SUPPORT
- if (IS_IA32_PROCESS(&scr->pt)) {
- scr->pt.r8 = scr->pt.r1;
- scr->pt.cr_iip -= 2;
- } else
- #endif
- ia64_decrement_ip(&scr->pt);
- }
- }
- /* Whee! Actually deliver the signal. If the
- delivery failed, we need to continue to iterate in
- this loop so we can deliver the SIGSEGV... */
- if (handle_signal(signr, ka, &info, oldset, scr))
- return 1;
- }
- /* Did we come from a system call? */
- if (restart) {
- /* Restart the system call - no handlers present */
- if (errno == ERESTARTNOHAND || errno == ERESTARTSYS || errno == ERESTARTNOINTR) {
- #ifdef CONFIG_IA32_SUPPORT
- if (IS_IA32_PROCESS(&scr->pt)) {
- scr->pt.r8 = scr->pt.r1;
- scr->pt.cr_iip -= 2;
- } else
- #endif
- /*
- * Note: the syscall number is in r15 which is
- * saved in pt_regs so all we need to do here
- * is adjust ip so that the "break"
- * instruction gets re-executed.
- */
- ia64_decrement_ip(&scr->pt);
- }
- }
- return 0;
- }