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Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c179
1 files changed, 90 insertions, 89 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 6c0958e52ea7..954f77d7e3bc 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -22,6 +22,7 @@
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/signalfd.h>
+#include <linux/tracehook.h>
#include <linux/capability.h>
#include <linux/freezer.h>
#include <linux/pid_namespace.h>
@@ -39,24 +40,21 @@
static struct kmem_cache *sigqueue_cachep;
-static int __sig_ignored(struct task_struct *t, int sig)
+static void __user *sig_handler(struct task_struct *t, int sig)
{
- void __user *handler;
+ return t->sighand->action[sig - 1].sa.sa_handler;
+}
+static int sig_handler_ignored(void __user *handler, int sig)
+{
/* Is it explicitly or implicitly ignored? */
-
- handler = t->sighand->action[sig - 1].sa.sa_handler;
return handler == SIG_IGN ||
(handler == SIG_DFL && sig_kernel_ignore(sig));
}
static int sig_ignored(struct task_struct *t, int sig)
{
- /*
- * Tracers always want to know about signals..
- */
- if (t->ptrace & PT_PTRACED)
- return 0;
+ void __user *handler;
/*
* Blocked signals are never ignored, since the
@@ -66,7 +64,14 @@ static int sig_ignored(struct task_struct *t, int sig)
if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
return 0;
- return __sig_ignored(t, sig);
+ handler = sig_handler(t, sig);
+ if (!sig_handler_ignored(handler, sig))
+ return 0;
+
+ /*
+ * Tracers may want to know about even ignored signals.
+ */
+ return !tracehook_consider_ignored_signal(t, sig, handler);
}
/*
@@ -129,7 +134,9 @@ void recalc_sigpending_and_wake(struct task_struct *t)
void recalc_sigpending(void)
{
- if (!recalc_sigpending_tsk(current) && !freezing(current))
+ if (unlikely(tracehook_force_sigpending()))
+ set_thread_flag(TIF_SIGPENDING);
+ else if (!recalc_sigpending_tsk(current) && !freezing(current))
clear_thread_flag(TIF_SIGPENDING);
}
@@ -295,12 +302,12 @@ flush_signal_handlers(struct task_struct *t, int force_default)
int unhandled_signal(struct task_struct *tsk, int sig)
{
+ void __user *handler = tsk->sighand->action[sig-1].sa.sa_handler;
if (is_global_init(tsk))
return 1;
- if (tsk->ptrace & PT_PTRACED)
+ if (handler != SIG_IGN && handler != SIG_DFL)
return 0;
- return (tsk->sighand->action[sig-1].sa.sa_handler == SIG_IGN) ||
- (tsk->sighand->action[sig-1].sa.sa_handler == SIG_DFL);
+ return !tracehook_consider_fatal_signal(tsk, sig, handler);
}
@@ -338,13 +345,9 @@ unblock_all_signals(void)
spin_unlock_irqrestore(&current->sighand->siglock, flags);
}
-static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
+static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
{
struct sigqueue *q, *first = NULL;
- int still_pending = 0;
-
- if (unlikely(!sigismember(&list->signal, sig)))
- return 0;
/*
* Collect the siginfo appropriate to this signal. Check if
@@ -352,33 +355,30 @@ static int collect_signal(int sig, struct sigpending *list, siginfo_t *info)
*/
list_for_each_entry(q, &list->list, list) {
if (q->info.si_signo == sig) {
- if (first) {
- still_pending = 1;
- break;
- }
+ if (first)
+ goto still_pending;
first = q;
}
}
+
+ sigdelset(&list->signal, sig);
+
if (first) {
+still_pending:
list_del_init(&first->list);
copy_siginfo(info, &first->info);
__sigqueue_free(first);
- if (!still_pending)
- sigdelset(&list->signal, sig);
} else {
-
/* Ok, it wasn't in the queue. This must be
a fast-pathed signal or we must have been
out of queue space. So zero out the info.
*/
- sigdelset(&list->signal, sig);
info->si_signo = sig;
info->si_errno = 0;
info->si_code = 0;
info->si_pid = 0;
info->si_uid = 0;
}
- return 1;
}
static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
@@ -396,8 +396,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
}
}
- if (!collect_signal(sig, pending, info))
- sig = 0;
+ collect_signal(sig, pending, info);
}
return sig;
@@ -462,8 +461,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
* is to alert stop-signal processing code when another
* processor has come along and cleared the flag.
*/
- if (!(tsk->signal->flags & SIGNAL_GROUP_EXIT))
- tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
+ tsk->signal->flags |= SIGNAL_STOP_DEQUEUED;
}
if ((info->si_code & __SI_MASK) == __SI_TIMER && info->si_sys_private) {
/*
@@ -600,9 +598,6 @@ static int check_kill_permission(int sig, struct siginfo *info,
return security_task_kill(t, info, sig, 0);
}
-/* forward decl */
-static void do_notify_parent_cldstop(struct task_struct *tsk, int why);
-
/*
* Handle magic process-wide effects of stop/continue signals. Unlike
* the signal actions, these happen immediately at signal-generation
@@ -765,7 +760,8 @@ static void complete_signal(int sig, struct task_struct *p, int group)
if (sig_fatal(p, sig) &&
!(signal->flags & (SIGNAL_UNKILLABLE | SIGNAL_GROUP_EXIT)) &&
!sigismember(&t->real_blocked, sig) &&
- (sig == SIGKILL || !(t->ptrace & PT_PTRACED))) {
+ (sig == SIGKILL ||
+ !tracehook_consider_fatal_signal(t, sig, SIG_DFL))) {
/*
* This signal will be fatal to the whole group.
*/
@@ -1125,7 +1121,7 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
* is probably wrong. Should make it like BSD or SYSV.
*/
-static int kill_something_info(int sig, struct siginfo *info, int pid)
+static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
{
int ret;
@@ -1237,17 +1233,6 @@ int kill_pid(struct pid *pid, int sig, int priv)
}
EXPORT_SYMBOL(kill_pid);
-int
-kill_proc(pid_t pid, int sig, int priv)
-{
- int ret;
-
- rcu_read_lock();
- ret = kill_pid_info(sig, __si_special(priv), find_pid(pid));
- rcu_read_unlock();
- return ret;
-}
-
/*
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
@@ -1343,9 +1328,11 @@ static inline void __wake_up_parent(struct task_struct *p,
/*
* Let a parent know about the death of a child.
* For a stopped/continued status change, use do_notify_parent_cldstop instead.
+ *
+ * Returns -1 if our parent ignored us and so we've switched to
+ * self-reaping, or else @sig.
*/
-
-void do_notify_parent(struct task_struct *tsk, int sig)
+int do_notify_parent(struct task_struct *tsk, int sig)
{
struct siginfo info;
unsigned long flags;
@@ -1379,10 +1366,9 @@ void do_notify_parent(struct task_struct *tsk, int sig)
info.si_uid = tsk->uid;
- /* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = cputime_to_jiffies(cputime_add(tsk->utime,
+ info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
tsk->signal->utime));
- info.si_stime = cputime_to_jiffies(cputime_add(tsk->stime,
+ info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
tsk->signal->stime));
info.si_status = tsk->exit_code & 0x7f;
@@ -1417,12 +1403,14 @@ void do_notify_parent(struct task_struct *tsk, int sig)
*/
tsk->exit_signal = -1;
if (psig->action[SIGCHLD-1].sa.sa_handler == SIG_IGN)
- sig = 0;
+ sig = -1;
}
if (valid_signal(sig) && sig > 0)
__group_send_sig_info(sig, &info, tsk->parent);
__wake_up_parent(tsk, tsk->parent);
spin_unlock_irqrestore(&psig->siglock, flags);
+
+ return sig;
}
static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
@@ -1450,9 +1438,8 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
info.si_uid = tsk->uid;
- /* FIXME: find out whether or not this is supposed to be c*time. */
- info.si_utime = cputime_to_jiffies(tsk->utime);
- info.si_stime = cputime_to_jiffies(tsk->stime);
+ info.si_utime = cputime_to_clock_t(tsk->utime);
+ info.si_stime = cputime_to_clock_t(tsk->stime);
info.si_code = why;
switch (why) {
@@ -1491,10 +1478,10 @@ static inline int may_ptrace_stop(void)
* is a deadlock situation, and pointless because our tracer
* is dead so don't allow us to stop.
* If SIGKILL was already sent before the caller unlocked
- * ->siglock we must see ->core_waiters != 0. Otherwise it
+ * ->siglock we must see ->core_state != NULL. Otherwise it
* is safe to enter schedule().
*/
- if (unlikely(current->mm->core_waiters) &&
+ if (unlikely(current->mm->core_state) &&
unlikely(current->mm == current->parent->mm))
return 0;
@@ -1507,9 +1494,8 @@ static inline int may_ptrace_stop(void)
*/
static int sigkill_pending(struct task_struct *tsk)
{
- return ((sigismember(&tsk->pending.signal, SIGKILL) ||
- sigismember(&tsk->signal->shared_pending.signal, SIGKILL)) &&
- !unlikely(sigismember(&tsk->blocked, SIGKILL)));
+ return sigismember(&tsk->pending.signal, SIGKILL) ||
+ sigismember(&tsk->signal->shared_pending.signal, SIGKILL);
}
/*
@@ -1525,8 +1511,6 @@ static int sigkill_pending(struct task_struct *tsk)
*/
static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
{
- int killed = 0;
-
if (arch_ptrace_stop_needed(exit_code, info)) {
/*
* The arch code has something special to do before a
@@ -1542,7 +1526,8 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
spin_unlock_irq(&current->sighand->siglock);
arch_ptrace_stop(exit_code, info);
spin_lock_irq(&current->sighand->siglock);
- killed = sigkill_pending(current);
+ if (sigkill_pending(current))
+ return;
}
/*
@@ -1559,7 +1544,7 @@ static void ptrace_stop(int exit_code, int clear_code, siginfo_t *info)
__set_current_state(TASK_TRACED);
spin_unlock_irq(&current->sighand->siglock);
read_lock(&tasklist_lock);
- if (!unlikely(killed) && may_ptrace_stop()) {
+ if (may_ptrace_stop()) {
do_notify_parent_cldstop(current, CLD_TRAPPED);
read_unlock(&tasklist_lock);
schedule();
@@ -1623,7 +1608,7 @@ finish_stop(int stop_count)
* a group stop in progress and we are the last to stop,
* report to the parent. When ptraced, every thread reports itself.
*/
- if (stop_count == 0 || (current->ptrace & PT_PTRACED)) {
+ if (tracehook_notify_jctl(stop_count == 0, CLD_STOPPED)) {
read_lock(&tasklist_lock);
do_notify_parent_cldstop(current, CLD_STOPPED);
read_unlock(&tasklist_lock);
@@ -1658,8 +1643,7 @@ static int do_signal_stop(int signr)
} else {
struct task_struct *t;
- if (unlikely((sig->flags & (SIGNAL_STOP_DEQUEUED | SIGNAL_UNKILLABLE))
- != SIGNAL_STOP_DEQUEUED) ||
+ if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED) ||
unlikely(signal_group_exit(sig)))
return 0;
/*
@@ -1760,6 +1744,9 @@ relock:
signal->flags &= ~SIGNAL_CLD_MASK;
spin_unlock_irq(&sighand->siglock);
+ if (unlikely(!tracehook_notify_jctl(1, why)))
+ goto relock;
+
read_lock(&tasklist_lock);
do_notify_parent_cldstop(current->group_leader, why);
read_unlock(&tasklist_lock);
@@ -1773,17 +1760,33 @@ relock:
do_signal_stop(0))
goto relock;
- signr = dequeue_signal(current, &current->blocked, info);
- if (!signr)
- break; /* will return 0 */
+ /*
+ * Tracing can induce an artifical signal and choose sigaction.
+ * The return value in @signr determines the default action,
+ * but @info->si_signo is the signal number we will report.
+ */
+ signr = tracehook_get_signal(current, regs, info, return_ka);
+ if (unlikely(signr < 0))
+ goto relock;
+ if (unlikely(signr != 0))
+ ka = return_ka;
+ else {
+ signr = dequeue_signal(current, &current->blocked,
+ info);
- if (signr != SIGKILL) {
- signr = ptrace_signal(signr, info, regs, cookie);
if (!signr)
- continue;
+ break; /* will return 0 */
+
+ if (signr != SIGKILL) {
+ signr = ptrace_signal(signr, info,
+ regs, cookie);
+ if (!signr)
+ continue;
+ }
+
+ ka = &sighand->action[signr-1];
}
- ka = &sighand->action[signr-1];
if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
continue;
if (ka->sa.sa_handler != SIG_DFL) {
@@ -1831,7 +1834,7 @@ relock:
spin_lock_irq(&sighand->siglock);
}
- if (likely(do_signal_stop(signr))) {
+ if (likely(do_signal_stop(info->si_signo))) {
/* It released the siglock. */
goto relock;
}
@@ -1852,7 +1855,7 @@ relock:
if (sig_kernel_coredump(signr)) {
if (print_fatal_signals)
- print_fatal_signal(regs, signr);
+ print_fatal_signal(regs, info->si_signo);
/*
* If it was able to dump core, this kills all
* other threads in the group and synchronizes with
@@ -1861,13 +1864,13 @@ relock:
* first and our do_group_exit call below will use
* that value and ignore the one we pass it.
*/
- do_coredump((long)signr, signr, regs);
+ do_coredump(info->si_signo, info->si_signo, regs);
}
/*
* Death signals, no core dump.
*/
- do_group_exit(signr);
+ do_group_exit(info->si_signo);
/* NOTREACHED */
}
spin_unlock_irq(&sighand->siglock);
@@ -1909,7 +1912,7 @@ void exit_signals(struct task_struct *tsk)
out:
spin_unlock_irq(&tsk->sighand->siglock);
- if (unlikely(group_stop)) {
+ if (unlikely(group_stop) && tracehook_notify_jctl(1, CLD_STOPPED)) {
read_lock(&tasklist_lock);
do_notify_parent_cldstop(tsk, CLD_STOPPED);
read_unlock(&tasklist_lock);
@@ -1920,8 +1923,6 @@ EXPORT_SYMBOL(recalc_sigpending);
EXPORT_SYMBOL_GPL(dequeue_signal);
EXPORT_SYMBOL(flush_signals);
EXPORT_SYMBOL(force_sig);
-EXPORT_SYMBOL(kill_proc);
-EXPORT_SYMBOL(ptrace_notify);
EXPORT_SYMBOL(send_sig);
EXPORT_SYMBOL(send_sig_info);
EXPORT_SYMBOL(sigprocmask);
@@ -2196,7 +2197,7 @@ sys_rt_sigtimedwait(const sigset_t __user *uthese,
}
asmlinkage long
-sys_kill(int pid, int sig)
+sys_kill(pid_t pid, int sig)
{
struct siginfo info;
@@ -2209,7 +2210,7 @@ sys_kill(int pid, int sig)
return kill_something_info(sig, &info, pid);
}
-static int do_tkill(int tgid, int pid, int sig)
+static int do_tkill(pid_t tgid, pid_t pid, int sig)
{
int error;
struct siginfo info;
@@ -2255,7 +2256,7 @@ static int do_tkill(int tgid, int pid, int sig)
* exists but it's not belonging to the target process anymore. This
* method solves the problem of threads exiting and PIDs getting reused.
*/
-asmlinkage long sys_tgkill(int tgid, int pid, int sig)
+asmlinkage long sys_tgkill(pid_t tgid, pid_t pid, int sig)
{
/* This is only valid for single tasks */
if (pid <= 0 || tgid <= 0)
@@ -2268,7 +2269,7 @@ asmlinkage long sys_tgkill(int tgid, int pid, int sig)
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
asmlinkage long
-sys_tkill(int pid, int sig)
+sys_tkill(pid_t pid, int sig)
{
/* This is only valid for single tasks */
if (pid <= 0)
@@ -2278,7 +2279,7 @@ sys_tkill(int pid, int sig)
}
asmlinkage long
-sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
+sys_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t __user *uinfo)
{
siginfo_t info;
@@ -2325,7 +2326,7 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
* (for example, SIGCHLD), shall cause the pending signal to
* be discarded, whether or not it is blocked"
*/
- if (__sig_ignored(t, sig)) {
+ if (sig_handler_ignored(sig_handler(t, sig), sig)) {
sigemptyset(&mask);
sigaddset(&mask, sig);
rm_from_queue_full(&mask, &t->signal->shared_pending);