summaryrefslogtreecommitdiffstats
path: root/kernel/signal.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c155
1 files changed, 111 insertions, 44 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 1186cf7fac7..7165af5f1b1 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -226,7 +226,7 @@ static inline void print_dropped_signal(int sig)
/*
* allocate a new signal queue record
* - this may be called without locks if and only if t == current, otherwise an
- * appopriate lock must be held to stop the target task from exiting
+ * appropriate lock must be held to stop the target task from exiting
*/
static struct sigqueue *
__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
@@ -375,15 +375,15 @@ int unhandled_signal(struct task_struct *tsk, int sig)
return !tracehook_consider_fatal_signal(tsk, sig);
}
-
-/* Notify the system that a driver wants to block all signals for this
+/*
+ * Notify the system that a driver wants to block all signals for this
* process, and wants to be notified if any signals at all were to be
* sent/acted upon. If the notifier routine returns non-zero, then the
* signal will be acted upon after all. If the notifier routine returns 0,
* then then signal will be blocked. Only one block per process is
* allowed. priv is a pointer to private data that the notifier routine
- * can use to determine if the signal should be blocked or not. */
-
+ * can use to determine if the signal should be blocked or not.
+ */
void
block_all_signals(int (*notifier)(void *priv), void *priv, sigset_t *mask)
{
@@ -434,9 +434,10 @@ still_pending:
copy_siginfo(info, &first->info);
__sigqueue_free(first);
} 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.
+ /*
+ * 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.
*/
info->si_signo = sig;
info->si_errno = 0;
@@ -468,7 +469,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
}
/*
- * Dequeue a signal and return the element to the caller, which is
+ * Dequeue a signal and return the element to the caller, which is
* expected to free it.
*
* All callers have to hold the siglock.
@@ -490,7 +491,7 @@ int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
* itimers are process shared and we restart periodic
* itimers in the signal delivery path to prevent DoS
* attacks in the high resolution timer case. This is
- * compliant with the old way of self restarting
+ * compliant with the old way of self-restarting
* itimers, as the SIGALRM is a legacy signal and only
* queued once. Changing the restart behaviour to
* restart the timer in the signal dequeue path is
@@ -923,14 +924,15 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
if (info == SEND_SIG_FORCED)
goto out_set;
- /* Real-time signals must be queued if sent by sigqueue, or
- some other real-time mechanism. It is implementation
- defined whether kill() does so. We attempt to do so, on
- the principle of least surprise, but since kill is not
- allowed to fail with EAGAIN when low on memory we just
- make sure at least one signal gets delivered and don't
- pass on the info struct. */
-
+ /*
+ * Real-time signals must be queued if sent by sigqueue, or
+ * some other real-time mechanism. It is implementation
+ * defined whether kill() does so. We attempt to do so, on
+ * the principle of least surprise, but since kill is not
+ * allowed to fail with EAGAIN when low on memory we just
+ * make sure at least one signal gets delivered and don't
+ * pass on the info struct.
+ */
if (sig < SIGRTMIN)
override_rlimit = (is_si_special(info) || info->si_code >= 0);
else
@@ -1201,8 +1203,7 @@ retry:
return error;
}
-int
-kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
{
int error;
rcu_read_lock();
@@ -1299,8 +1300,7 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
* These are for backward compatibility with the rest of the kernel source.
*/
-int
-send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
{
/*
* Make sure legacy kernel users don't send in bad values
@@ -1368,7 +1368,7 @@ EXPORT_SYMBOL(kill_pid);
* These functions support sending signals using preallocated sigqueue
* structures. This is needed "because realtime applications cannot
* afford to lose notifications of asynchronous events, like timer
- * expirations or I/O completions". In the case of Posix Timers
+ * expirations or I/O completions". In the case of POSIX Timers
* we allocate the sigqueue structure from the timer_create. If this
* allocation fails we are able to report the failure to the application
* with an EAGAIN error.
@@ -1553,7 +1553,7 @@ static void do_notify_parent_cldstop(struct task_struct *tsk, int why)
info.si_signo = SIGCHLD;
info.si_errno = 0;
/*
- * see comment in do_notify_parent() abot the following 3 lines
+ * see comment in do_notify_parent() about the following 4 lines
*/
rcu_read_lock();
info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
@@ -1611,7 +1611,7 @@ static inline int may_ptrace_stop(void)
}
/*
- * Return nonzero if there is a SIGKILL that should be waking us up.
+ * Return non-zero if there is a SIGKILL that should be waking us up.
* Called with the siglock held.
*/
static int sigkill_pending(struct task_struct *tsk)
@@ -1735,7 +1735,7 @@ void ptrace_notify(int exit_code)
/*
* This performs the stopping for SIGSTOP and other stop signals.
* We have to stop all threads in the thread group.
- * Returns nonzero if we've actually stopped and released the siglock.
+ * Returns non-zero if we've actually stopped and released the siglock.
* Returns zero if we didn't stop and still hold the siglock.
*/
static int do_signal_stop(int signr)
@@ -1823,10 +1823,12 @@ static int ptrace_signal(int signr, siginfo_t *info,
current->exit_code = 0;
- /* Update the siginfo structure if the signal has
- changed. If the debugger wanted something
- specific in the siginfo structure then it should
- have updated *info via PTRACE_SETSIGINFO. */
+ /*
+ * Update the siginfo structure if the signal has
+ * changed. If the debugger wanted something
+ * specific in the siginfo structure then it should
+ * have updated *info via PTRACE_SETSIGINFO.
+ */
if (signr != info->si_signo) {
info->si_signo = signr;
info->si_errno = 0;
@@ -1885,7 +1887,7 @@ relock:
for (;;) {
struct k_sigaction *ka;
/*
- * Tracing can induce an artifical signal and choose sigaction.
+ * Tracing can induce an artificial signal and choose sigaction.
* The return value in @signr determines the default action,
* but @info->si_signo is the signal number we will report.
*/
@@ -2034,7 +2036,8 @@ void exit_signals(struct task_struct *tsk)
if (!signal_pending(tsk))
goto out;
- /* It could be that __group_complete_signal() choose us to
+ /*
+ * It could be that __group_complete_signal() choose us to
* notify about group-wide signal. Another thread should be
* woken now to take the signal since we will not.
*/
@@ -2072,6 +2075,9 @@ EXPORT_SYMBOL(unblock_all_signals);
* System call entry points.
*/
+/**
+ * sys_restart_syscall - restart a system call
+ */
SYSCALL_DEFINE0(restart_syscall)
{
struct restart_block *restart = &current_thread_info()->restart_block;
@@ -2125,6 +2131,13 @@ int sigprocmask(int how, sigset_t *set, sigset_t *oldset)
return error;
}
+/**
+ * sys_rt_sigprocmask - change the list of currently blocked signals
+ * @how: whether to add, remove, or set signals
+ * @set: stores pending signals
+ * @oset: previous value of signal mask if non-null
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigprocmask, int, how, sigset_t __user *, set,
sigset_t __user *, oset, size_t, sigsetsize)
{
@@ -2183,8 +2196,14 @@ long do_sigpending(void __user *set, unsigned long sigsetsize)
out:
return error;
-}
+}
+/**
+ * sys_rt_sigpending - examine a pending signal that has been raised
+ * while blocked
+ * @set: stores pending signals
+ * @sigsetsize: size of sigset_t type or larger
+ */
SYSCALL_DEFINE2(rt_sigpending, sigset_t __user *, set, size_t, sigsetsize)
{
return do_sigpending(set, sigsetsize);
@@ -2233,9 +2252,9 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
err |= __put_user(from->si_trapno, &to->si_trapno);
#endif
#ifdef BUS_MCEERR_AO
- /*
+ /*
* Other callers might not initialize the si_lsb field,
- * so check explicitely for the right codes here.
+ * so check explicitly for the right codes here.
*/
if (from->si_code == BUS_MCEERR_AR || from->si_code == BUS_MCEERR_AO)
err |= __put_user(from->si_addr_lsb, &to->si_addr_lsb);
@@ -2264,6 +2283,14 @@ int copy_siginfo_to_user(siginfo_t __user *to, siginfo_t *from)
#endif
+/**
+ * sys_rt_sigtimedwait - synchronously wait for queued signals specified
+ * in @uthese
+ * @uthese: queued signals to wait for
+ * @uinfo: if non-null, the signal's siginfo is returned here
+ * @uts: upper bound on process time suspension
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
siginfo_t __user *, uinfo, const struct timespec __user *, uts,
size_t, sigsetsize)
@@ -2280,7 +2307,7 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
if (copy_from_user(&these, uthese, sizeof(these)))
return -EFAULT;
-
+
/*
* Invert the set of allowed signals to get those we
* want to block.
@@ -2305,9 +2332,11 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
+ (ts.tv_sec || ts.tv_nsec));
if (timeout) {
- /* None ready -- temporarily unblock those we're
+ /*
+ * None ready -- temporarily unblock those we're
* interested while we are sleeping in so that we'll
- * be awakened when they arrive. */
+ * be awakened when they arrive.
+ */
current->real_blocked = current->blocked;
sigandsets(&current->blocked, &current->blocked, &these);
recalc_sigpending();
@@ -2339,6 +2368,11 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
return ret;
}
+/**
+ * sys_kill - send a signal to a process
+ * @pid: the PID of the process
+ * @sig: signal to be sent
+ */
SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
{
struct siginfo info;
@@ -2414,7 +2448,11 @@ SYSCALL_DEFINE3(tgkill, pid_t, tgid, pid_t, pid, int, sig)
return do_tkill(tgid, pid, sig);
}
-/*
+/**
+ * sys_tkill - send signal to one specific task
+ * @pid: the PID of the task
+ * @sig: signal to be sent
+ *
* Send a signal to only one task, even if it's a CLONE_THREAD task.
*/
SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
@@ -2426,6 +2464,12 @@ SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
return do_tkill(0, pid, sig);
}
+/**
+ * sys_rt_sigqueueinfo - send signal information to a signal
+ * @pid: the PID of the thread
+ * @sig: signal to be sent
+ * @uinfo: signal info to be sent
+ */
SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
siginfo_t __user *, uinfo)
{
@@ -2553,12 +2597,11 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
error = -EINVAL;
/*
- *
- * Note - this code used to test ss_flags incorrectly
+ * Note - this code used to test ss_flags incorrectly:
* old code may have been written using ss_flags==0
* to mean ss_flags==SS_ONSTACK (as this was the only
* way that worked) - this fix preserves that older
- * mechanism
+ * mechanism.
*/
if (ss_flags != SS_DISABLE && ss_flags != SS_ONSTACK && ss_flags != 0)
goto out;
@@ -2592,6 +2635,10 @@ out:
#ifdef __ARCH_WANT_SYS_SIGPENDING
+/**
+ * sys_sigpending - examine pending signals
+ * @set: where mask of pending signal is returned
+ */
SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
{
return do_sigpending(set, sizeof(*set));
@@ -2600,8 +2647,15 @@ SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set)
#endif
#ifdef __ARCH_WANT_SYS_SIGPROCMASK
-/* Some platforms have their own version with special arguments others
- support only sys_rt_sigprocmask. */
+/**
+ * sys_sigprocmask - examine and change blocked signals
+ * @how: whether to add, remove, or set signals
+ * @set: signals to add or remove (if non-null)
+ * @oset: previous value of signal mask if non-null
+ *
+ * Some platforms have their own version with special arguments;
+ * others support only sys_rt_sigprocmask.
+ */
SYSCALL_DEFINE3(sigprocmask, int, how, old_sigset_t __user *, set,
old_sigset_t __user *, oset)
@@ -2654,6 +2708,13 @@ out:
#endif /* __ARCH_WANT_SYS_SIGPROCMASK */
#ifdef __ARCH_WANT_SYS_RT_SIGACTION
+/**
+ * sys_rt_sigaction - alter an action taken by a process
+ * @sig: signal to be sent
+ * @act: new sigaction
+ * @oact: used to save the previous sigaction
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE4(rt_sigaction, int, sig,
const struct sigaction __user *, act,
struct sigaction __user *, oact,
@@ -2740,6 +2801,12 @@ SYSCALL_DEFINE0(pause)
#endif
#ifdef __ARCH_WANT_SYS_RT_SIGSUSPEND
+/**
+ * sys_rt_sigsuspend - replace the signal mask for a value with the
+ * @unewset value until a signal is received
+ * @unewset: new signal mask value
+ * @sigsetsize: size of sigset_t type
+ */
SYSCALL_DEFINE2(rt_sigsuspend, sigset_t __user *, unewset, size_t, sigsetsize)
{
sigset_t newset;