signal.c
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上传日期:2013-04-10
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文件大小:17k
- /* $Id: signal.c,v 1.21 2000/03/11 14:06:21 gniibe Exp $
- *
- * linux/arch/sh/kernel/signal.c
- *
- * Copyright (C) 1991, 1992 Linus Torvalds
- *
- * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
- *
- * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima
- *
- */
- #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 <linux/stddef.h>
- #include <linux/personality.h>
- #include <asm/ucontext.h>
- #include <asm/uaccess.h>
- #include <asm/pgtable.h>
- #define DEBUG_SIG 0
- #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
- asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
- 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.
- */
- asmlinkage int
- sys_sigsuspend(old_sigset_t mask,
- unsigned long r5, unsigned long r6, unsigned long r7,
- struct pt_regs regs)
- {
- sigset_t saveset;
- mask &= _BLOCKABLE;
- spin_lock_irq(¤t->sigmask_lock);
- saveset = current->blocked;
- siginitset(¤t->blocked, mask);
- recalc_sigpending(current);
- spin_unlock_irq(¤t->sigmask_lock);
- regs.regs[0] = -EINTR;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(®s, &saveset))
- return -EINTR;
- }
- }
- asmlinkage int
- sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize,
- unsigned long r6, unsigned long r7,
- struct pt_regs regs)
- {
- sigset_t saveset, newset;
- /* XXX: Don't preclude handling different sized sigset_t's. */
- if (sigsetsize != sizeof(sigset_t))
- return -EINVAL;
- 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[0] = -EINTR;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(®s, &saveset))
- return -EINTR;
- }
- }
- asmlinkage int
- sys_sigaction(int sig, const struct old_sigaction *act,
- struct old_sigaction *oact)
- {
- struct k_sigaction new_ka, old_ka;
- int ret;
- if (act) {
- old_sigset_t mask;
- if (verify_area(VERIFY_READ, act, sizeof(*act)) ||
- __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
- __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
- return -EFAULT;
- __get_user(new_ka.sa.sa_flags, &act->sa_flags);
- __get_user(mask, &act->sa_mask);
- siginitset(&new_ka.sa.sa_mask, mask);
- }
- ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
- if (!ret && oact) {
- if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) ||
- __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
- __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
- return -EFAULT;
- __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
- __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
- }
- return ret;
- }
- asmlinkage int
- sys_sigaltstack(const stack_t *uss, stack_t *uoss,
- unsigned long r6, unsigned long r7,
- struct pt_regs regs)
- {
- return do_sigaltstack(uss, uoss, regs.regs[15]);
- }
- /*
- * Do a signal return; undo the signal stack.
- */
- struct sigframe
- {
- struct sigcontext sc;
- unsigned long extramask[_NSIG_WORDS-1];
- char retcode[4];
- };
- struct rt_sigframe
- {
- struct siginfo *pinfo;
- void *puc;
- struct siginfo info;
- struct ucontext uc;
- char retcode[4];
- };
- #if defined(__SH4__)
- static inline int restore_sigcontext_fpu(struct sigcontext *sc)
- {
- struct task_struct *tsk = current;
- tsk->used_math = 1;
- return __copy_from_user(&tsk->thread.fpu.hard, &sc->sc_fpregs[0],
- sizeof(long)*(16*2+2));
- }
- static inline int save_sigcontext_fpu(struct sigcontext *sc)
- {
- struct task_struct *tsk = current;
- unsigned long flags;
- int val;
- if (!tsk->used_math) {
- val = 0;
- __copy_to_user(&sc->sc_ownedfp, &val, sizeof(int));
- return 0;
- }
- val = 1;
- __copy_to_user(&sc->sc_ownedfp, &val, sizeof(int));
- /* This will cause a "finit" to be triggered by the next
- attempted FPU operation by the 'current' process.
- */
- tsk->used_math = 0;
- save_and_cli(flags);
- unlazy_fpu(tsk);
- restore_flags(flags);
- return __copy_to_user(&sc->sc_fpregs[0], &tsk->thread.fpu.hard,
- sizeof(long)*(16*2+2));
- }
- #endif
- static int
- restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *r0_p)
- {
- unsigned int err = 0;
- #define COPY(x) err |= __get_user(regs->x, &sc->sc_##x)
- COPY(regs[1]);
- COPY(regs[2]); COPY(regs[3]);
- COPY(regs[4]); COPY(regs[5]);
- COPY(regs[6]); COPY(regs[7]);
- COPY(regs[8]); COPY(regs[9]);
- COPY(regs[10]); COPY(regs[11]);
- COPY(regs[12]); COPY(regs[13]);
- COPY(regs[14]); COPY(regs[15]);
- COPY(gbr); COPY(mach);
- COPY(macl); COPY(pr);
- COPY(sr); COPY(pc);
- #undef COPY
- #if defined(__SH4__)
- {
- int owned_fp;
- struct task_struct *tsk = current;
- regs->sr |= SR_FD; /* Release FPU */
- clear_fpu(tsk);
- current->used_math = 0;
- __get_user (owned_fp, &sc->sc_ownedfp);
- if (owned_fp)
- err |= restore_sigcontext_fpu(sc);
- }
- #endif
- regs->syscall_nr = -1; /* disable syscall checks */
- err |= __get_user(*r0_p, &sc->sc_regs[0]);
- return err;
- }
- asmlinkage int sys_sigreturn(unsigned long r4, unsigned long r5,
- unsigned long r6, unsigned long r7,
- struct pt_regs regs)
- {
- struct sigframe *frame = (struct sigframe *)regs.regs[15];
- sigset_t set;
- int r0;
- if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
- goto badframe;
- if (__get_user(set.sig[0], &frame->sc.oldmask)
- || (_NSIG_WORDS > 1
- && __copy_from_user(&set.sig[1], &frame->extramask,
- sizeof(frame->extramask))))
- 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->sc, &r0))
- goto badframe;
- return r0;
- badframe:
- force_sig(SIGSEGV, current);
- return 0;
- }
- asmlinkage int sys_rt_sigreturn(unsigned long r4, unsigned long r5,
- unsigned long r6, unsigned long r7,
- struct pt_regs regs)
- {
- struct rt_sigframe *frame = (struct rt_sigframe *)regs.regs[15];
- sigset_t set;
- stack_t st;
- int r0;
- if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
- goto badframe;
- if (__copy_from_user(&set, &frame->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->uc.uc_mcontext, &r0))
- goto badframe;
- if (__copy_from_user(&st, &frame->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[15]);
- return r0;
- badframe:
- force_sig(SIGSEGV, current);
- return 0;
- }
- /*
- * Set up a signal frame.
- */
- static int
- setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
- unsigned long mask)
- {
- int err = 0;
- #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x)
- COPY(regs[0]); COPY(regs[1]);
- COPY(regs[2]); COPY(regs[3]);
- COPY(regs[4]); COPY(regs[5]);
- COPY(regs[6]); COPY(regs[7]);
- COPY(regs[8]); COPY(regs[9]);
- COPY(regs[10]); COPY(regs[11]);
- COPY(regs[12]); COPY(regs[13]);
- COPY(regs[14]); COPY(regs[15]);
- COPY(gbr); COPY(mach);
- COPY(macl); COPY(pr);
- COPY(sr); COPY(pc);
- #undef COPY
- #if defined(__SH4__)
- err |= save_sigcontext_fpu(sc);
- #endif
- /* non-iBCS2 extensions.. */
- err |= __put_user(mask, &sc->oldmask);
- return err;
- }
- /*
- * Determine which stack to use..
- */
- static inline void *
- get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
- {
- if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! on_sig_stack(sp))
- sp = current->sas_ss_sp + current->sas_ss_size;
- return (void *)((sp - frame_size) & -8ul);
- }
- static void setup_frame(int sig, struct k_sigaction *ka,
- sigset_t *set, struct pt_regs *regs)
- {
- struct sigframe *frame;
- int err = 0;
- int signal;
- frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
- goto give_sigsegv;
- signal = current->exec_domain
- && current->exec_domain->signal_invmap
- && sig < 32
- ? current->exec_domain->signal_invmap[sig]
- : sig;
- err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
- if (_NSIG_WORDS > 1) {
- err |= __copy_to_user(frame->extramask, &set->sig[1],
- sizeof(frame->extramask));
- }
- /* Set up to return from userspace. If provided, use a stub
- already in userspace. */
- if (ka->sa.sa_flags & SA_RESTORER) {
- regs->pr = (unsigned long) ka->sa.sa_restorer;
- } else {
- /* This is : mov #__NR_sigreturn,r3 ; trapa #0x10 */
- #ifdef __LITTLE_ENDIAN__
- unsigned long code = 0xc310e300 | (__NR_sigreturn);
- #else
- unsigned long code = 0xe300c310 | (__NR_sigreturn << 16);
- #endif
- regs->pr = (unsigned long) frame->retcode;
- err |= __put_user(code, (long *)(frame->retcode+0));
- }
- if (err)
- goto give_sigsegv;
- /* Set up registers for signal handler */
- regs->regs[15] = (unsigned long) frame;
- regs->regs[4] = signal; /* Arg for signal handler */
- regs->pc = (unsigned long) ka->sa.sa_handler;
- set_fs(USER_DS);
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lxn",
- current->comm, current->pid, frame, regs->pc, regs->pr);
- #endif
- flush_cache_sigtramp(regs->pr);
- return;
- give_sigsegv:
- if (sig == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, current);
- }
- static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs *regs)
- {
- struct rt_sigframe *frame;
- int err = 0;
- int signal;
- frame = get_sigframe(ka, regs->regs[15], sizeof(*frame));
- if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
- goto give_sigsegv;
- signal = current->exec_domain
- && current->exec_domain->signal_invmap
- && sig < 32
- ? current->exec_domain->signal_invmap[sig]
- : sig;
- err |= __put_user(&frame->info, &frame->pinfo);
- err |= __put_user(&frame->uc, &frame->puc);
- err |= copy_siginfo_to_user(&frame->info, info);
- /* Create the ucontext. */
- err |= __put_user(0, &frame->uc.uc_flags);
- err |= __put_user(0, &frame->uc.uc_link);
- err |= __put_user((void *)current->sas_ss_sp,
- &frame->uc.uc_stack.ss_sp);
- err |= __put_user(sas_ss_flags(regs->regs[15]),
- &frame->uc.uc_stack.ss_flags);
- err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= setup_sigcontext(&frame->uc.uc_mcontext,
- regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- /* Set up to return from userspace. If provided, use a stub
- already in userspace. */
- if (ka->sa.sa_flags & SA_RESTORER) {
- regs->pr = (unsigned long) ka->sa.sa_restorer;
- } else {
- /* This is : mov #__NR_rt_sigreturn,r3 ; trapa #0x10 */
- #ifdef __LITTLE_ENDIAN__
- unsigned long code = 0xc310e300 | (__NR_rt_sigreturn);
- #else
- unsigned long code = 0xe300c310 | (__NR_rt_sigreturn << 16);
- #endif
- regs->pr = (unsigned long) frame->retcode;
- err |= __put_user(code, (long *)(frame->retcode+0));
- }
- if (err)
- goto give_sigsegv;
- /* Set up registers for signal handler */
- regs->regs[15] = (unsigned long) frame;
- regs->regs[4] = signal; /* Arg for signal handler */
- regs->pc = (unsigned long) ka->sa.sa_handler;
- set_fs(USER_DS);
- #if DEBUG_SIG
- printk("SIG deliver (%s:%d): sp=%p pc=%08lx pr=%08lxn",
- current->comm, current->pid, frame, regs->pc, regs->pr);
- #endif
- flush_cache_sigtramp(regs->pr);
- return;
- give_sigsegv:
- if (sig == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, current);
- }
- /*
- * OK, we're invoking a handler
- */
- static void
- handle_signal(unsigned long sig, struct k_sigaction *ka,
- siginfo_t *info, sigset_t *oldset, struct pt_regs * regs)
- {
- /* Are we from a system call? */
- if (regs->syscall_nr >= 0) {
- /* If so, check system call restarting.. */
- switch (regs->regs[0]) {
- case -ERESTARTNOHAND:
- regs->regs[0] = -EINTR;
- break;
- case -ERESTARTSYS:
- if (!(ka->sa.sa_flags & SA_RESTART)) {
- regs->regs[0] = -EINTR;
- break;
- }
- /* fallthrough */
- case -ERESTARTNOINTR:
- regs->regs[0] = regs->syscall_nr;
- regs->pc -= 2;
- }
- }
- /* Set up the stack frame */
- if (ka->sa.sa_flags & SA_SIGINFO)
- setup_rt_frame(sig, ka, info, oldset, regs);
- else
- setup_frame(sig, ka, oldset, regs);
- 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);
- }
- }
- /*
- * 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.
- *
- * Note that we go through the signals twice: once to check the signals that
- * the kernel can handle, and then we build all the user-level signal handling
- * stack-frames in one go after that.
- */
- int do_signal(struct pt_regs *regs, sigset_t *oldset)
- {
- siginfo_t info;
- struct k_sigaction *ka;
- /*
- * 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(regs))
- return 1;
- 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:
- sig_exit(signr, exit_code, &info);
- /* NOTREACHED */
- }
- }
- /* Whee! Actually deliver the signal. */
- handle_signal(signr, ka, &info, oldset, regs);
- return 1;
- }
- /* Did we come from a system call? */
- if (regs->syscall_nr >= 0) {
- /* Restart the system call - no handlers present */
- if (regs->regs[0] == -ERESTARTNOHAND ||
- regs->regs[0] == -ERESTARTSYS ||
- regs->regs[0] == -ERESTARTNOINTR) {
- regs->regs[0] = regs->syscall_nr;
- regs->pc -= 2;
- }
- }
- return 0;
- }