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/*
* linux/arch/i386/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
* 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes
*/
#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/tty.h>
#include <linux/personality.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#define DEBUG_SIG 0
#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
int FASTCALL(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(int history0, int history1, old_sigset_t mask)
{
struct pt_regs * regs = (struct pt_regs *) &history0;
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->eax = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &saveset))
return -EINTR;
}
}
asmlinkage int
sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize)
{
struct pt_regs * regs = (struct pt_regs *) &unewset;
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->eax = -EINTR;
while (1) {
current->state = TASK_INTERRUPTIBLE;
schedule();
if (do_signal(regs, &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)
{
struct pt_regs *regs = (struct pt_regs *) &uss;
return do_sigaltstack(uss, uoss, regs->esp);
}
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe
{
char *pretcode;
int sig;
struct sigcontext sc;
struct _fpstate fpstate;
unsigned long extramask[_NSIG_WORDS-1];
char retcode[8];
};
struct rt_sigframe
{
char *pretcode;
int sig;
struct siginfo *pinfo;
void *puc;
struct siginfo info;
struct ucontext uc;
struct _fpstate fpstate;
char retcode[8];
};
static int
restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *peax)
{
unsigned int err = 0;
#define COPY(x) err |= __get_user(regs->x, &sc->x)
#define COPY_SEG(seg) \
{ unsigned short tmp; \
err |= __get_user(tmp, &sc->seg); \
regs->x##seg = tmp; }
#define COPY_SEG_STRICT(seg) \
{ unsigned short tmp; \
err |= __get_user(tmp, &sc->seg); \
regs->x##seg = tmp|3; }
#define GET_SEG(seg) \
{ unsigned short tmp; \
err |= __get_user(tmp, &sc->seg); \
loadsegment(seg,tmp); }
GET_SEG(gs);
GET_SEG(fs);
COPY_SEG(es);
COPY_SEG(ds);
COPY(edi);
COPY(esi);
COPY(ebp);
COPY(esp);
COPY(ebx);
COPY(edx);
COPY(ecx);
COPY(eip);
COPY_SEG_STRICT(cs);
COPY_SEG_STRICT(ss);
{
unsigned int tmpflags;
err |= __get_user(tmpflags, &sc->eflags);
regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
regs->orig_eax = -1; /* disable syscall checks */
}
{
struct _fpstate * buf;
err |= __get_user(buf, &sc->fpstate);
if (buf) {
if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
goto badframe;
err |= restore_i387(buf);
}
}
err |= __get_user(*peax, &sc->eax);
return err;
badframe:
return 1;
}
asmlinkage int sys_sigreturn(unsigned long __unused)
{
struct pt_regs *regs = (struct pt_regs *) &__unused;
struct sigframe *frame = (struct sigframe *)(regs->esp - 8);
sigset_t set;
int eax;
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, &eax))
goto badframe;
return eax;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
asmlinkage int sys_rt_sigreturn(unsigned long __unused)
{
struct pt_regs *regs = (struct pt_regs *) &__unused;
struct rt_sigframe *frame = (struct rt_sigframe *)(regs->esp - 4);
sigset_t set;
stack_t st;
int eax;
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, &eax))
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->esp);
return eax;
badframe:
force_sig(SIGSEGV, current);
return 0;
}
/*
* Set up a signal frame.
*/
static int
setup_sigcontext(struct sigcontext *sc, struct _fpstate *fpstate,
struct pt_regs *regs, unsigned long mask)
{
int tmp, err = 0;
tmp = 0;
__asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
err |= __put_user(tmp, (unsigned int *)&sc->gs);
__asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
err |= __put_user(tmp, (unsigned int *)&sc->fs);
err |= __put_user(regs->xes, (unsigned int *)&sc->es);
err |= __put_user(regs->xds, (unsigned int *)&sc->ds);
err |= __put_user(regs->edi, &sc->edi);
err |= __put_user(regs->esi, &sc->esi);
err |= __put_user(regs->ebp, &sc->ebp);
err |= __put_user(regs->esp, &sc->esp);
err |= __put_user(regs->ebx, &sc->ebx);
err |= __put_user(regs->edx, &sc->edx);
err |= __put_user(regs->ecx, &sc->ecx);
err |= __put_user(regs->eax, &sc->eax);
err |= __put_user(current->thread.trap_no, &sc->trapno);
err |= __put_user(current->thread.error_code, &sc->err);
err |= __put_user(regs->eip, &sc->eip);
err |= __put_user(regs->xcs, (unsigned int *)&sc->cs);
err |= __put_user(regs->eflags, &sc->eflags);
err |= __put_user(regs->esp, &sc->esp_at_signal);
err |= __put_user(regs->xss, (unsigned int *)&sc->ss);
tmp = save_i387(fpstate);
if (tmp < 0)
err = 1;
else
err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate);
/* non-iBCS2 extensions.. */
err |= __put_user(mask, &sc->oldmask);
err |= __put_user(current->thread.cr2, &sc->cr2);
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 esp;
/* Default to using normal stack */
esp = regs->esp;
/* This is the X/Open sanctioned signal stack switching. */
if (ka->sa.sa_flags & SA_ONSTACK) {
if (sas_ss_flags(esp) == 0)
esp = current->sas_ss_sp + current->sas_ss_size;
}
/* This is the legacy signal stack switching. */
else if ((regs->xss & 0xffff) != __USER_DS &&
!(ka->sa.sa_flags & SA_RESTORER) &&
ka->sa.sa_restorer) {
esp = (unsigned long) ka->sa.sa_restorer;
}
return (void *)((esp - 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;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
err |= __put_user((current->exec_domain
&& current->exec_domain->signal_invmap
&& sig < 32
? current->exec_domain->signal_invmap[sig]
: sig),
&frame->sig);
if (err)
goto give_sigsegv;
err |= setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]);
if (err)
goto give_sigsegv;
if (_NSIG_WORDS > 1) {
err |= __copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
}
if (err)
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
} else {
#ifdef CONFIG_HARDEN_STACK
err |= __put_user(MAGIC_SIGRETURN, &frame->pretcode);
#else
err |= __put_user(frame->retcode, &frame->pretcode);
/* This is popl %eax ; movl $,%eax ; int $0x80 */
err |= __put_user(0xb858, (short *)(frame->retcode+0));
err |= __put_user(__NR_sigreturn, (int *)(frame->retcode+2));
err |= __put_user(0x80cd, (short *)(frame->retcode+6));
#endif
}
if (err)
goto give_sigsegv;
/* Set up registers for signal handler */
regs->esp = (unsigned long) frame;
regs->eip = (unsigned long) ka->sa.sa_handler;
set_fs(USER_DS);
regs->xds = __USER_DS;
regs->xes = __USER_DS;
regs->xss = __USER_DS;
regs->xcs = __USER_CS;
regs->eflags &= ~TF_MASK;
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif
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;
frame = get_sigframe(ka, regs, sizeof(*frame));
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto give_sigsegv;
err |= __put_user((current->exec_domain
&& current->exec_domain->signal_invmap
&& sig < 32
? current->exec_domain->signal_invmap[sig]
: sig),
&frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, info);
if (err)
goto give_sigsegv;
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->esp),
&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, &frame->fpstate,
regs, set->sig[0]);
err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
if (err)
goto give_sigsegv;
/* Set up to return from userspace. If provided, use a stub
already in userspace. */
if (ka->sa.sa_flags & SA_RESTORER) {
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
} else {
#ifdef CONFIG_HARDEN_STACK
err |= __put_user(MAGIC_RT_SIGRETURN, &frame->pretcode);
#else
err |= __put_user(frame->retcode, &frame->pretcode);
/* This is movl $,%eax ; int $0x80 */
err |= __put_user(0xb8, (char *)(frame->retcode+0));
err |= __put_user(__NR_rt_sigreturn, (int *)(frame->retcode+1));
err |= __put_user(0x80cd, (short *)(frame->retcode+5));
#endif
}
if (err)
goto give_sigsegv;
/* Set up registers for signal handler */
regs->esp = (unsigned long) frame;
regs->eip = (unsigned long) ka->sa.sa_handler;
set_fs(USER_DS);
regs->xds = __USER_DS;
regs->xes = __USER_DS;
regs->xss = __USER_DS;
regs->xcs = __USER_CS;
regs->eflags &= ~TF_MASK;
#if DEBUG_SIG
printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n",
current->comm, current->pid, frame, regs->eip, frame->pretcode);
#endif
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->orig_eax >= 0) {
/* If so, check system call restarting.. */
switch (regs->eax) {
case -ERESTARTNOHAND:
regs->eax = -EINTR;
break;
case -ERESTARTSYS:
if (!(ka->sa.sa_flags & SA_RESTART)) {
regs->eax = -EINTR;
break;
}
/* fallthrough */
case -ERESTARTNOINTR:
regs->eax = regs->orig_eax;
regs->eip -= 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.
*/
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 ((regs->xcs & 3) != 3)
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: {
struct signal_struct *sig;
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, regs))
exit_code |= 0x80;
/* FALLTHRU */
default:
sigaddset(¤t->pending.signal, signr);
recalc_sigpending(current);
current->flags |= PF_SIGNALED;
do_exit(exit_code);
/* NOTREACHED */
}
}
/* Reenable any watchpoints before delivering the
* signal to user space. The processor register will
* have been cleared if the watchpoint triggered
* inside the kernel.
*/
__asm__("movl %0,%%db7" : : "r" (current->thread.debugreg[7]));
/* Whee! Actually deliver the signal. */
handle_signal(signr, ka, &info, oldset, regs);
return 1;
}
/* Did we come from a system call? */
if (regs->orig_eax >= 0) {
/* Restart the system call - no handlers present */
if (regs->eax == -ERESTARTNOHAND ||
regs->eax == -ERESTARTSYS ||
regs->eax == -ERESTARTNOINTR) {
regs->eax = regs->orig_eax;
regs->eip -= 2;
}
}
return 0;
}
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