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authorRoland McGrath <roland@redhat.com>2008-07-25 22:45:51 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-26 15:00:09 -0400
commit35de254dc60f91004b3b5ebb1fc7b2c3093d6032 (patch)
tree101e174247bb3174c8abe0fb8d1405ed6a4db6d1 /kernel
parentc45aea27617d6a1e0aacddc3b0233f704222fcbd (diff)
tracehook: tracehook_consider_ignored_signal
This defines tracehook_consider_ignored_signal() has a fine-grained hook for deciding to prevent the normal short-circuit of sending an ignored signal, as ptrace does. There is no change, only cleanup. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/signal.c27
1 files changed, 16 insertions, 11 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 8715c18b27b9..9efd1cee6d0b 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -22,6 +22,7 @@
22#include <linux/ptrace.h> 22#include <linux/ptrace.h>
23#include <linux/signal.h> 23#include <linux/signal.h>
24#include <linux/signalfd.h> 24#include <linux/signalfd.h>
25#include <linux/tracehook.h>
25#include <linux/capability.h> 26#include <linux/capability.h>
26#include <linux/freezer.h> 27#include <linux/freezer.h>
27#include <linux/pid_namespace.h> 28#include <linux/pid_namespace.h>
@@ -39,24 +40,21 @@
39 40
40static struct kmem_cache *sigqueue_cachep; 41static struct kmem_cache *sigqueue_cachep;
41 42
42static int __sig_ignored(struct task_struct *t, int sig) 43static void __user *sig_handler(struct task_struct *t, int sig)
43{ 44{
44 void __user *handler; 45 return t->sighand->action[sig - 1].sa.sa_handler;
46}
45 47
48static int sig_handler_ignored(void __user *handler, int sig)
49{
46 /* Is it explicitly or implicitly ignored? */ 50 /* Is it explicitly or implicitly ignored? */
47
48 handler = t->sighand->action[sig - 1].sa.sa_handler;
49 return handler == SIG_IGN || 51 return handler == SIG_IGN ||
50 (handler == SIG_DFL && sig_kernel_ignore(sig)); 52 (handler == SIG_DFL && sig_kernel_ignore(sig));
51} 53}
52 54
53static int sig_ignored(struct task_struct *t, int sig) 55static int sig_ignored(struct task_struct *t, int sig)
54{ 56{
55 /* 57 void __user *handler;
56 * Tracers always want to know about signals..
57 */
58 if (t->ptrace & PT_PTRACED)
59 return 0;
60 58
61 /* 59 /*
62 * Blocked signals are never ignored, since the 60 * Blocked signals are never ignored, since the
@@ -66,7 +64,14 @@ static int sig_ignored(struct task_struct *t, int sig)
66 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig)) 64 if (sigismember(&t->blocked, sig) || sigismember(&t->real_blocked, sig))
67 return 0; 65 return 0;
68 66
69 return __sig_ignored(t, sig); 67 handler = sig_handler(t, sig);
68 if (!sig_handler_ignored(handler, sig))
69 return 0;
70
71 /*
72 * Tracers may want to know about even ignored signals.
73 */
74 return !tracehook_consider_ignored_signal(t, sig, handler);
70} 75}
71 76
72/* 77/*
@@ -2298,7 +2303,7 @@ int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
2298 * (for example, SIGCHLD), shall cause the pending signal to 2303 * (for example, SIGCHLD), shall cause the pending signal to
2299 * be discarded, whether or not it is blocked" 2304 * be discarded, whether or not it is blocked"
2300 */ 2305 */
2301 if (__sig_ignored(t, sig)) { 2306 if (sig_handler_ignored(sig_handler(t, sig), sig)) {
2302 sigemptyset(&mask); 2307 sigemptyset(&mask);
2303 sigaddset(&mask, sig); 2308 sigaddset(&mask, sig);
2304 rm_from_queue_full(&mask, &t->signal->shared_pending); 2309 rm_from_queue_full(&mask, &t->signal->shared_pending);