signal.c
上传用户:lgb322
上传日期:2013-02-24
资源大小:30529k
文件大小:17k
- /*
- * linux/arch/arm/kernel/signal.c
- *
- * Copyright (C) 1995-2001 Russell King
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
- #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/errno.h>
- #include <linux/signal.h>
- #include <linux/wait.h>
- #include <linux/ptrace.h>
- #include <linux/stddef.h>
- #include <linux/unistd.h>
- #include <linux/personality.h>
- #include <linux/tty.h>
- #include <linux/elf.h>
- #include <asm/pgalloc.h>
- #include <asm/ucontext.h>
- #include <asm/uaccess.h>
- #include "ptrace.h"
- #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
- /*
- * For ARM syscalls, we encode the syscall number into the instruction.
- */
- #define SWI_SYS_SIGRETURN (0xef000000|(__NR_sigreturn))
- #define SWI_SYS_RT_SIGRETURN (0xef000000|(__NR_rt_sigreturn))
- /*
- * For Thumb syscalls, we pass the syscall number via r7. We therefore
- * need two 16-bit instructions.
- */
- #define SWI_THUMB_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_sigreturn - __NR_SYSCALL_BASE))
- #define SWI_THUMB_RT_SIGRETURN (0xdf00 << 16 | 0x2700 | (__NR_rt_sigreturn - __NR_SYSCALL_BASE))
- static const unsigned long retcodes[4] = {
- SWI_SYS_SIGRETURN, SWI_THUMB_SIGRETURN,
- SWI_SYS_RT_SIGRETURN, SWI_THUMB_RT_SIGRETURN
- };
- asmlinkage int do_signal(sigset_t *oldset, struct pt_regs * regs, int syscall);
- int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
- {
- int err = -EFAULT;;
- if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t)))
- goto out;
- if (from->si_code < 0)
- return __copy_to_user(to, from, sizeof(siginfo_t));
- /* 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. */
- }
- out:
- return err;
- }
- /*
- * atomically swap in the new signal mask, and wait for a signal.
- */
- asmlinkage int sys_sigsuspend(int restart, unsigned long oldmask, old_sigset_t mask, 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->ARM_r0 = -EINTR;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, regs, 0))
- return regs->ARM_r0;
- }
- }
- asmlinkage int
- sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize, 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->ARM_r0 = -EINTR;
- while (1) {
- current->state = TASK_INTERRUPTIBLE;
- schedule();
- if (do_signal(&saveset, regs, 0))
- return regs->ARM_r0;
- }
- }
- 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;
- }
- /*
- * Do a signal return; undo the signal stack.
- */
- struct sigframe
- {
- struct sigcontext sc;
- unsigned long extramask[_NSIG_WORDS-1];
- unsigned long retcode;
- };
- struct rt_sigframe
- {
- struct siginfo *pinfo;
- void *puc;
- struct siginfo info;
- struct ucontext uc;
- unsigned long retcode;
- };
- static int
- restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
- {
- int err = 0;
- __get_user_error(regs->ARM_r0, &sc->arm_r0, err);
- __get_user_error(regs->ARM_r1, &sc->arm_r1, err);
- __get_user_error(regs->ARM_r2, &sc->arm_r2, err);
- __get_user_error(regs->ARM_r3, &sc->arm_r3, err);
- __get_user_error(regs->ARM_r4, &sc->arm_r4, err);
- __get_user_error(regs->ARM_r5, &sc->arm_r5, err);
- __get_user_error(regs->ARM_r6, &sc->arm_r6, err);
- __get_user_error(regs->ARM_r7, &sc->arm_r7, err);
- __get_user_error(regs->ARM_r8, &sc->arm_r8, err);
- __get_user_error(regs->ARM_r9, &sc->arm_r9, err);
- __get_user_error(regs->ARM_r10, &sc->arm_r10, err);
- __get_user_error(regs->ARM_fp, &sc->arm_fp, err);
- __get_user_error(regs->ARM_ip, &sc->arm_ip, err);
- __get_user_error(regs->ARM_sp, &sc->arm_sp, err);
- __get_user_error(regs->ARM_lr, &sc->arm_lr, err);
- __get_user_error(regs->ARM_pc, &sc->arm_pc, err);
- #ifdef CONFIG_CPU_32
- __get_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
- #endif
- err |= !valid_user_regs(regs);
- return err;
- }
- asmlinkage int sys_sigreturn(struct pt_regs *regs)
- {
- struct sigframe *frame;
- sigset_t set;
- /*
- * Since we stacked the signal on a 64-bit boundary,
- * then 'sp' should be word aligned here. If it's
- * not, then the user is trying to mess with us.
- */
- if (regs->ARM_sp & 7)
- goto badframe;
- frame = (struct sigframe *)regs->ARM_sp;
- 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(regs, &frame->sc))
- goto badframe;
- /* Send SIGTRAP if we're single-stepping */
- if (ptrace_cancel_bpt(current))
- send_sig(SIGTRAP, current, 1);
- return regs->ARM_r0;
- badframe:
- force_sig(SIGSEGV, current);
- return 0;
- }
- asmlinkage int sys_rt_sigreturn(struct pt_regs *regs)
- {
- struct rt_sigframe *frame;
- sigset_t set;
- /*
- * Since we stacked the signal on a 64-bit boundary,
- * then 'sp' should be word aligned here. If it's
- * not, then the user is trying to mess with us.
- */
- if (regs->ARM_sp & 7)
- goto badframe;
- frame = (struct rt_sigframe *)regs->ARM_sp;
- 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(regs, &frame->uc.uc_mcontext))
- goto badframe;
- /* Send SIGTRAP if we're single-stepping */
- if (ptrace_cancel_bpt(current))
- send_sig(SIGTRAP, current, 1);
- return regs->ARM_r0;
- badframe:
- force_sig(SIGSEGV, current);
- return 0;
- }
- static int
- setup_sigcontext(struct sigcontext *sc, /*struct _fpstate *fpstate,*/
- struct pt_regs *regs, unsigned long mask)
- {
- int err = 0;
- __put_user_error(regs->ARM_r0, &sc->arm_r0, err);
- __put_user_error(regs->ARM_r1, &sc->arm_r1, err);
- __put_user_error(regs->ARM_r2, &sc->arm_r2, err);
- __put_user_error(regs->ARM_r3, &sc->arm_r3, err);
- __put_user_error(regs->ARM_r4, &sc->arm_r4, err);
- __put_user_error(regs->ARM_r5, &sc->arm_r5, err);
- __put_user_error(regs->ARM_r6, &sc->arm_r6, err);
- __put_user_error(regs->ARM_r7, &sc->arm_r7, err);
- __put_user_error(regs->ARM_r8, &sc->arm_r8, err);
- __put_user_error(regs->ARM_r9, &sc->arm_r9, err);
- __put_user_error(regs->ARM_r10, &sc->arm_r10, err);
- __put_user_error(regs->ARM_fp, &sc->arm_fp, err);
- __put_user_error(regs->ARM_ip, &sc->arm_ip, err);
- __put_user_error(regs->ARM_sp, &sc->arm_sp, err);
- __put_user_error(regs->ARM_lr, &sc->arm_lr, err);
- __put_user_error(regs->ARM_pc, &sc->arm_pc, err);
- #ifdef CONFIG_CPU_32
- __put_user_error(regs->ARM_cpsr, &sc->arm_cpsr, err);
- #endif
- __put_user_error(current->thread.trap_no, &sc->trap_no, err);
- __put_user_error(current->thread.error_code, &sc->error_code, err);
- __put_user_error(current->thread.address, &sc->fault_address, err);
- __put_user_error(mask, &sc->oldmask, err);
- return err;
- }
- static inline void *
- get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, int framesize)
- {
- unsigned long sp = regs->ARM_sp;
- /*
- * This is the X/Open sanctioned signal stack switching.
- */
- if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
- sp = current->sas_ss_sp + current->sas_ss_size;
- /*
- * ATPCS B01 mandates 8-byte alignment
- */
- return (void *)((sp - framesize) & ~7);
- }
- static int
- setup_return(struct pt_regs *regs, struct k_sigaction *ka,
- unsigned long *rc, void *frame, int usig)
- {
- unsigned long handler = (unsigned long)ka->sa.sa_handler;
- unsigned long retcode;
- int thumb = 0;
- #ifdef CONFIG_CPU_32
- unsigned long cpsr = regs->ARM_cpsr;
- /*
- * Maybe we need to deliver a 32-bit signal to a 26-bit task.
- */
- if (ka->sa.sa_flags & SA_THIRTYTWO)
- cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
- #ifdef CONFIG_ARM_THUMB
- if (elf_hwcap & HWCAP_THUMB) {
- /*
- * The LSB of the handler determines if we're going to
- * be using THUMB or ARM mode for this signal handler.
- */
- thumb = handler & 1;
- if (thumb)
- cpsr |= T_BIT;
- else
- cpsr &= ~T_BIT;
- }
- #endif
- #endif
- if (ka->sa.sa_flags & SA_RESTORER) {
- retcode = (unsigned long)ka->sa.sa_restorer;
- } else {
- unsigned int idx = thumb;
- if (ka->sa.sa_flags & SA_SIGINFO)
- idx += 2;
- if (__put_user(retcodes[idx], rc))
- return 1;
- flush_icache_range((unsigned long)rc,
- (unsigned long)(rc + 1));
- retcode = ((unsigned long)rc) + thumb;
- }
- regs->ARM_r0 = usig;
- regs->ARM_sp = (unsigned long)frame;
- regs->ARM_lr = retcode;
- regs->ARM_pc = handler & (thumb ? ~1 : ~3);
- #ifdef CONFIG_CPU_32
- regs->ARM_cpsr = cpsr;
- #endif
- return 0;
- }
- static int
- setup_frame(int usig, struct k_sigaction *ka, sigset_t *set, struct pt_regs *regs)
- {
- struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
- int err = 0;
- if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
- return 1;
- err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]);
- if (_NSIG_WORDS > 1) {
- err |= __copy_to_user(frame->extramask, &set->sig[1],
- sizeof(frame->extramask));
- }
- if (err == 0)
- err = setup_return(regs, ka, &frame->retcode, frame, usig);
- return err;
- }
- static int
- setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
- sigset_t *set, struct pt_regs *regs)
- {
- struct rt_sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
- int err = 0;
- if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
- return 1;
- __put_user_error(&frame->info, &frame->pinfo, err);
- __put_user_error(&frame->uc, &frame->puc, err);
- err |= copy_siginfo_to_user(&frame->info, info);
- /* Clear all the bits of the ucontext we don't use. */
- err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
- err |= setup_sigcontext(&frame->uc.uc_mcontext, /*&frame->fpstate,*/
- regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- if (err == 0)
- err = setup_return(regs, ka, &frame->retcode, frame, usig);
- if (err == 0) {
- /*
- * For realtime signals we must also set the second and third
- * arguments for the signal handler.
- * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
- */
- regs->ARM_r1 = (unsigned long)frame->pinfo;
- regs->ARM_r2 = (unsigned long)frame->puc;
- }
- return err;
- }
- /*
- * 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)
- {
- struct task_struct *tsk = current;
- int usig = sig;
- int ret;
- /*
- * translate the signal
- */
- if (usig < 32 && tsk->exec_domain && tsk->exec_domain->signal_invmap)
- usig = tsk->exec_domain->signal_invmap[usig];
- /*
- * Set up the stack frame
- */
- if (ka->sa.sa_flags & SA_SIGINFO)
- ret = setup_rt_frame(usig, ka, info, oldset, regs);
- else
- ret = setup_frame(usig, ka, oldset, regs);
- /*
- * Check that the resulting registers are actually sane.
- */
- ret |= !valid_user_regs(regs);
- if (ret == 0) {
- if (ka->sa.sa_flags & SA_ONESHOT)
- ka->sa.sa_handler = SIG_DFL;
- if (!(ka->sa.sa_flags & SA_NODEFER)) {
- spin_lock_irq(&tsk->sigmask_lock);
- sigorsets(&tsk->blocked, &tsk->blocked,
- &ka->sa.sa_mask);
- sigaddset(&tsk->blocked, sig);
- recalc_sigpending(tsk);
- spin_unlock_irq(&tsk->sigmask_lock);
- }
- return;
- }
- if (sig == SIGSEGV)
- ka->sa.sa_handler = SIG_DFL;
- force_sig(SIGSEGV, tsk);
- }
- /*
- * 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.
- */
- asmlinkage int do_signal(sigset_t *oldset, struct pt_regs *regs, int syscall)
- {
- struct k_sigaction *ka;
- siginfo_t info;
- int single_stepping;
- /*
- * 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 0;
- if (!oldset)
- oldset = ¤t->blocked;
- single_stepping = ptrace_cancel_bpt(current);
- 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();
- single_stepping |= ptrace_cancel_bpt(current);
- /* 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 */
- }
- }
- /* Are we from a system call? */
- if (syscall) {
- switch (regs->ARM_r0) {
- case -ERESTARTNOHAND:
- regs->ARM_r0 = -EINTR;
- break;
- case -ERESTARTSYS:
- if (!(ka->sa.sa_flags & SA_RESTART)) {
- regs->ARM_r0 = -EINTR;
- break;
- }
- /* fallthrough */
- case -ERESTARTNOINTR:
- regs->ARM_r0 = regs->ARM_ORIG_r0;
- regs->ARM_pc -= 4;
- }
- }
- /* Whee! Actually deliver the signal. */
- handle_signal(signr, ka, &info, oldset, regs);
- if (single_stepping)
- ptrace_set_bpt(current);
- return 1;
- }
- if (syscall &&
- (regs->ARM_r0 == -ERESTARTNOHAND ||
- regs->ARM_r0 == -ERESTARTSYS ||
- regs->ARM_r0 == -ERESTARTNOINTR)) {
- regs->ARM_r0 = regs->ARM_ORIG_r0;
- regs->ARM_pc -= 4;
- }
- if (single_stepping)
- ptrace_set_bpt(current);
- return 0;
- }