signal.c
上传用户:lgb322
上传日期:2013-02-24
资源大小:30529k
文件大小:18k
- /*
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- * Copyright (C) 1994 - 1999 Ralf Baechle
- * Copyright (C) 1999 Silicon Graphics, Inc.
- */
- #include <linux/config.h>
- #include <linux/sched.h>
- #include <linux/mm.h>
- #include <linux/smp.h>
- #include <linux/smp_lock.h>
- #include <linux/kernel.h>
- #include <linux/signal.h>
- #include <linux/errno.h>
- #include <linux/wait.h>
- #include <linux/ptrace.h>
- #include <linux/unistd.h>
- #include <asm/asm.h>
- #include <asm/bitops.h>
- #include <asm/pgalloc.h>
- #include <asm/stackframe.h>
- #include <asm/uaccess.h>
- #include <asm/ucontext.h>
- #define DEBUG_SIG 0
- #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
- extern asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs);
- extern asmlinkage int (*save_fp_context)(struct sigcontext *sc);
- extern asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
- extern asmlinkage void syscall_trace(void);
- 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);
- /* First 32bits of unions are always present. */
- err |= __put_user(from->si_pid, &to->si_pid);
- switch (from->si_code >> 16) {
- case __SI_FAULT >> 16:
- 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);
- default:
- err |= __put_user(from->si_uid, &to->si_uid);
- break;
- /* case __SI_RT: This is not generated by the kernel as of now. */
- }
- return err;
- }
- }
- /*
- * Atomically swap in the new signal mask, and wait for a signal.
- */
- save_static_function(sys_sigsuspend);
- static_unused int
- _sys_sigsuspend(struct pt_regs regs)
- {
- sigset_t *uset, saveset, newset;
- uset = (sigset_t *) regs.regs[4];
- if (copy_from_user(&newset, uset, sizeof(sigset_t)))
- return -EFAULT;
- sigdelsetmask(&newset, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- saveset = current->blocked;
- current->blocked = newset;
- recalc_sigpending(current);
- spin_unlock_irq(¤t->sigmask_lock);
- regs.regs[2] = EINTR;
- regs.regs[7] = 1;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, ®s))
- return -EINTR;
- }
- }
- save_static_function(sys_rt_sigsuspend);
- static_unused int
- _sys_rt_sigsuspend(struct pt_regs regs)
- {
- sigset_t *unewset, saveset, newset;
- size_t sigsetsize;
- /* XXX Don't preclude handling different sized sigset_t's. */
- sigsetsize = regs.regs[5];
- if (sigsetsize != sizeof(sigset_t))
- return -EINVAL;
- unewset = (sigset_t *) regs.regs[4];
- if (copy_from_user(&newset, unewset, sizeof(newset)))
- return -EFAULT;
- sigdelsetmask(&newset, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- saveset = current->blocked;
- current->blocked = newset;
- recalc_sigpending(current);
- spin_unlock_irq(¤t->sigmask_lock);
- regs.regs[2] = EINTR;
- regs.regs[7] = 1;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, ®s))
- return -EINTR;
- }
- }
- asmlinkage int
- sys_sigaction(int sig, const struct sigaction *act, struct sigaction *oact)
- {
- struct k_sigaction new_ka, old_ka;
- int ret;
- int err = 0;
- if (act) {
- old_sigset_t mask;
- if (!access_ok(VERIFY_READ, act, sizeof(*act)))
- return -EFAULT;
- err |= __get_user(new_ka.sa.sa_handler, &act->sa_handler);
- err |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
- err |= __get_user(mask, &act->sa_mask.sig[0]);
- err |= __get_user(new_ka.sa.sa_restorer, &act->sa_restorer);
- if (err)
- return -EFAULT;
- siginitset(&new_ka.sa.sa_mask, mask);
- }
- ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
- if (!ret && oact) {
- if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
- return -EFAULT;
- err |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
- err |= __put_user(old_ka.sa.sa_handler, &oact->sa_handler);
- err |= __put_user(old_ka.sa.sa_mask.sig[0], oact->sa_mask.sig);
- err |= __put_user(0, &oact->sa_mask.sig[1]);
- err |= __put_user(0, &oact->sa_mask.sig[2]);
- err |= __put_user(0, &oact->sa_mask.sig[3]);
- err |= __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer);
- if (err)
- return -EFAULT;
- }
- return ret;
- }
- asmlinkage int
- sys_sigaltstack(struct pt_regs regs)
- {
- const stack_t *uss = (const stack_t *) regs.regs[4];
- stack_t *uoss = (stack_t *) regs.regs[5];
- unsigned long usp = regs.regs[29];
- return do_sigaltstack(uss, uoss, usp);
- }
- asmlinkage int
- restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
- {
- int owned_fp;
- int err = 0;
- u64 reg;
- err |= __get_user(regs->cp0_epc, &sc->sc_pc);
- err |= __get_user(reg, &sc->sc_mdhi);
- regs->hi = (int) reg;
- err |= __get_user(reg, &sc->sc_mdlo);
- regs->lo = (int) reg;
- #define restore_gp_reg(i) do {
- err |= __get_user(reg, &sc->sc_regs[i]);
- regs->regs[i] = reg;
- } while(0);
- restore_gp_reg( 1); restore_gp_reg( 2); restore_gp_reg( 3);
- restore_gp_reg( 4); restore_gp_reg( 5); restore_gp_reg( 6);
- restore_gp_reg( 7); restore_gp_reg( 8); restore_gp_reg( 9);
- restore_gp_reg(10); restore_gp_reg(11); restore_gp_reg(12);
- restore_gp_reg(13); restore_gp_reg(14); restore_gp_reg(15);
- restore_gp_reg(16); restore_gp_reg(17); restore_gp_reg(18);
- restore_gp_reg(19); restore_gp_reg(20); restore_gp_reg(21);
- restore_gp_reg(22); restore_gp_reg(23); restore_gp_reg(24);
- restore_gp_reg(25); restore_gp_reg(26); restore_gp_reg(27);
- restore_gp_reg(28); restore_gp_reg(29); restore_gp_reg(30);
- restore_gp_reg(31);
- #undef restore_gp_reg
- err |= __get_user(owned_fp, &sc->sc_ownedfp);
- if (owned_fp) {
- err |= restore_fp_context(sc);
- last_task_used_math = current;
- }
- return err;
- }
- struct sigframe {
- u32 sf_ass[4]; /* argument save space for o32 */
- u32 sf_code[2]; /* signal trampoline */
- struct sigcontext sf_sc;
- sigset_t sf_mask;
- };
- struct rt_sigframe {
- u32 rs_ass[4]; /* argument save space for o32 */
- u32 rs_code[2]; /* signal trampoline */
- struct siginfo rs_info;
- struct ucontext rs_uc;
- };
- asmlinkage void
- sys_sigreturn(struct pt_regs regs)
- {
- struct sigframe *frame;
- sigset_t blocked;
- frame = (struct sigframe *) regs.regs[29];
- if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
- goto badframe;
- if (__copy_from_user(&blocked, &frame->sf_mask, sizeof(blocked)))
- goto badframe;
- sigdelsetmask(&blocked, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- current->blocked = blocked;
- recalc_sigpending(current);
- spin_unlock_irq(¤t->sigmask_lock);
- if (restore_sigcontext(®s, &frame->sf_sc))
- goto badframe;
- /*
- * Don't let your children do this ...
- */
- if (current->ptrace & PT_TRACESYS)
- syscall_trace();
- __asm__ __volatile__(
- "movet$29, %0nt"
- "jtret_from_sys_call"
- :/* no outputs */
- :"r" (®s));
- /* Unreached */
- badframe:
- force_sig(SIGSEGV, current);
- }
- asmlinkage void
- sys_rt_sigreturn(struct pt_regs regs)
- {
- struct rt_sigframe *frame;
- sigset_t set;
- stack_t st;
- frame = (struct rt_sigframe *) regs.regs[29];
- if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
- goto badframe;
- if (__copy_from_user(&set, &frame->rs_uc.uc_sigmask, sizeof(set)))
- goto badframe;
- sigdelsetmask(&set, ~_BLOCKABLE);
- spin_lock_irq(¤t->sigmask_lock);
- current->blocked = set;
- recalc_sigpending(current);
- spin_unlock_irq(¤t->sigmask_lock);
- if (restore_sigcontext(®s, &frame->rs_uc.uc_mcontext))
- goto badframe;
- if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
- goto badframe;
- /* It is more difficult to avoid calling this function than to
- call it and ignore errors. */
- do_sigaltstack(&st, NULL, regs.regs[29]);
- /*
- * Don't let your children do this ...
- */
- __asm__ __volatile__(
- "movet$29, %0nt"
- "jtret_from_sys_call"
- :/* no outputs */
- :"r" (®s));
- /* Unreached */
- badframe:
- force_sig(SIGSEGV, current);
- }
- static int inline
- setup_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
- {
- int owned_fp;
- int err = 0;
- u64 reg;
- err |= __put_user(regs->cp0_epc, &sc->sc_pc);
- err |= __put_user(regs->cp0_status, &sc->sc_status);
- #define save_gp_reg(i) {
- reg = regs->regs[i];
- err |= __put_user(reg, &sc->sc_regs[i]);
- } while(0)
- __put_user(0, &sc->sc_regs[0]); save_gp_reg(1); save_gp_reg(2);
- save_gp_reg(3); save_gp_reg(4); save_gp_reg(5); save_gp_reg(6);
- save_gp_reg(7); save_gp_reg(8); save_gp_reg(9); save_gp_reg(10);
- save_gp_reg(11); save_gp_reg(12); save_gp_reg(13); save_gp_reg(14);
- save_gp_reg(15); save_gp_reg(16); save_gp_reg(17); save_gp_reg(18);
- save_gp_reg(19); save_gp_reg(20); save_gp_reg(21); save_gp_reg(22);
- save_gp_reg(23); save_gp_reg(24); save_gp_reg(25); save_gp_reg(26);
- save_gp_reg(27); save_gp_reg(28); save_gp_reg(29); save_gp_reg(30);
- save_gp_reg(31);
- #undef save_gp_reg
- err |= __put_user(regs->hi, &sc->sc_mdhi);
- err |= __put_user(regs->lo, &sc->sc_mdlo);
- err |= __put_user(regs->cp0_cause, &sc->sc_cause);
- err |= __put_user(regs->cp0_badvaddr, &sc->sc_badvaddr);
- owned_fp = (current == last_task_used_math);
- err |= __put_user(owned_fp, &sc->sc_ownedfp);
- if (current->used_math) { /* fp is active. */
- set_cp0_status(ST0_CU1);
- err |= save_fp_context(sc);
- last_task_used_math = NULL;
- regs->cp0_status &= ~ST0_CU1;
- current->used_math = 0;
- }
- return err;
- }
- /*
- * Determine which stack to use..
- */
- static inline void *
- get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size)
- {
- unsigned long sp;
- /* Default to using normal stack */
- sp = regs->regs[29];
- /* This is the X/Open sanctioned signal stack switching. */
- if ((ka->sa.sa_flags & SA_ONSTACK) && ! on_sig_stack(sp))
- sp = current->sas_ss_sp + current->sas_ss_size;
- return (void *)((sp - frame_size) & ALMASK);
- }
- static void inline
- setup_frame(struct k_sigaction * ka, struct pt_regs *regs,
- int signr, sigset_t *set)
- {
- struct sigframe *frame;
- int err = 0;
- frame = get_sigframe(ka, regs, sizeof(*frame));
- if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
- goto give_sigsegv;
- /* Set up to return from userspace. If provided, use a stub already
- in userspace. */
- if (ka->sa.sa_flags & SA_RESTORER)
- regs->regs[31] = (unsigned long) ka->sa.sa_restorer;
- else {
- /*
- * Set up the return code ...
- *
- * li v0, __NR_sigreturn
- * syscall
- */
- err |= __put_user(0x24020000 + __NR_sigreturn,
- frame->sf_code + 0);
- err |= __put_user(0x0000000c ,
- frame->sf_code + 1);
- flush_cache_sigtramp((unsigned long) frame->sf_code);
- }
- err |= setup_sigcontext(regs, &frame->sf_sc);
- err |= __copy_to_user(&frame->sf_mask, set, sizeof(*set));
- if (err)
- goto give_sigsegv;
- /*
- * Arguments to signal handler:
- *
- * a0 = signal number
- * a1 = 0 (should be cause)
- * a2 = pointer to struct sigcontext
- *
- * $25 and c0_epc point to the signal handler, $29 points to the
- * struct sigframe.
- */
- regs->regs[ 4] = signr;
- regs->regs[ 5] = 0;
- regs->regs[ 6] = (unsigned long) &frame->sf_sc;
- regs->regs[29] = (unsigned long) frame;
- regs->regs[31] = (unsigned long) frame->sf_code;
- regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=0x%p pc=0x%p ra=0x%pn",
- current->comm, current->pid, frame, regs->cp0_epc, frame->code);
- #endif
- return;
- give_sigsegv:
- if (signr == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, current);
- }
- static void inline
- setup_rt_frame(struct k_sigaction * ka, struct pt_regs *regs,
- int signr, sigset_t *set, siginfo_t *info)
- {
- struct rt_sigframe *frame;
- int err = 0;
- frame = get_sigframe(ka, regs, sizeof(*frame));
- if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
- goto give_sigsegv;
- /* Set up to return from userspace. If provided, use a stub already
- in userspace. */
- if (ka->sa.sa_flags & SA_RESTORER)
- regs->regs[31] = (unsigned long) ka->sa.sa_restorer;
- else {
- /*
- * Set up the return code ...
- *
- * li v0, __NR_rt_sigreturn
- * syscall
- */
- err |= __put_user(0x24020000 + __NR_rt_sigreturn,
- frame->rs_code + 0);
- err |= __put_user(0x0000000c ,
- frame->rs_code + 1);
- flush_cache_sigtramp((unsigned long) frame->rs_code);
- }
- /* Create siginfo. */
- err |= copy_siginfo_to_user(&frame->rs_info, info);
- /* Create the ucontext. */
- err |= __put_user(0, &frame->rs_uc.uc_flags);
- err |= __put_user(0, &frame->rs_uc.uc_link);
- err |= __put_user((void *)current->sas_ss_sp,
- &frame->rs_uc.uc_stack.ss_sp);
- err |= __put_user(sas_ss_flags(regs->regs[29]),
- &frame->rs_uc.uc_stack.ss_flags);
- err |= __put_user(current->sas_ss_size,
- &frame->rs_uc.uc_stack.ss_size);
- err |= setup_sigcontext(regs, &frame->rs_uc.uc_mcontext);
- err |= __copy_to_user(&frame->rs_uc.uc_sigmask, set, sizeof(*set));
- if (err)
- goto give_sigsegv;
- /*
- * Arguments to signal handler:
- *
- * a0 = signal number
- * a1 = 0 (should be cause)
- * a2 = pointer to ucontext
- *
- * $25 and c0_epc point to the signal handler, $29 points to
- * the struct rt_sigframe.
- */
- regs->regs[ 4] = signr;
- regs->regs[ 5] = (unsigned long) &frame->rs_info;
- regs->regs[ 6] = (unsigned long) &frame->rs_uc;
- regs->regs[29] = (unsigned long) frame;
- regs->regs[31] = (unsigned long) frame->rs_code;
- regs->cp0_epc = regs->regs[25] = (unsigned long) ka->sa.sa_handler;
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=0x%p pc=0x%p ra=0x%pn",
- current->comm, current->pid, frame, regs->cp0_epc, frame->code);
- #endif
- return;
- give_sigsegv:
- if (signr == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, current);
- }
- static inline void
- handle_signal(unsigned long sig, struct k_sigaction *ka,
- siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
- {
- if (ka->sa.sa_flags & SA_SIGINFO)
- setup_rt_frame(ka, regs, sig, oldset, info);
- else
- setup_frame(ka, regs, sig, oldset);
- 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);
- }
- }
- static inline void
- syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
- {
- switch(regs->regs[0]) {
- case ERESTARTNOHAND:
- regs->regs[2] = EINTR;
- break;
- case ERESTARTSYS:
- if(!(ka->sa.sa_flags & SA_RESTART)) {
- regs->regs[2] = EINTR;
- break;
- }
- /* fallthrough */
- case ERESTARTNOINTR: /* Userland will reload $v0. */
- regs->regs[7] = regs->regs[26];
- regs->cp0_epc -= 8;
- }
- regs->regs[0] = 0; /* Don't deal with this again. */
- }
- extern int do_irix_signal(sigset_t *oldset, struct pt_regs *regs);
- asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs)
- {
- struct k_sigaction *ka;
- siginfo_t info;
- #ifdef CONFIG_BINFMT_IRIX
- if (current->personality != PER_LINUX)
- return do_irix_signal(oldset, regs);
- #endif
- if (!oldset)
- oldset = ¤t->blocked;
- 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->state = TASK_STOPPED;
- notify_parent(current, SIGCHLD);
- schedule();
- /* We're back. Did the debugger cancel the sig? */
- if (!(signr = current->exit_code))
- 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;
- if (!(current->p_pptr->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, regs))
- exit_code |= 0x80;
- /* FALLTHRU */
- default:
- sigaddset(¤t->pending.signal, signr);
- recalc_sigpending(current);
- current->flags |= PF_SIGNALED;
- do_exit(exit_code);
- /* NOTREACHED */
- }
- }
- if (regs->regs[0])
- syscall_restart(regs, ka);
- /* Whee! Actually deliver the signal. */
- handle_signal(signr, ka, &info, oldset, regs);
- return 1;
- }
- /*
- * Who's code doesn't conform to the restartable syscall convention
- * dies here!!! The li instruction, a single machine instruction,
- * must directly be followed by the syscall instruction.
- */
- if (regs->regs[0]) {
- if (regs->regs[2] == ERESTARTNOHAND ||
- regs->regs[2] == ERESTARTSYS ||
- regs->regs[2] == ERESTARTNOINTR) {
- regs->regs[7] = regs->regs[26];
- regs->cp0_epc -= 8;
- }
- }
- return 0;
- }