1 #include <signal.h>
2 #include <errno.h>
3 #include <string.h>
4 #include "syscall.h"
5 #include "pthread_impl.h"
6 #include "libc.h"
7 #include "lock.h"
8 #include "ksigaction.h"
9
10 static volatile int dummy_lock[1] = { 0 };
11
12 extern hidden volatile int __abort_lock[1];
13
14 weak_alias(dummy_lock, __abort_lock);
15
16 static int unmask_done;
17 static unsigned long handler_set[_NSIG/(8*sizeof(long))];
18
__get_handler_set(sigset_t * set)19 void __get_handler_set(sigset_t *set)
20 {
21 memcpy(set, handler_set, sizeof handler_set);
22 }
23
24 volatile int __eintr_valid_flag;
25
__libc_sigaction(int sig,const struct sigaction * restrict sa,struct sigaction * restrict old)26 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
27 {
28 struct k_sigaction ksa, ksa_old;
29 unsigned long set[_NSIG/(8*sizeof(long))];
30 if (sa) {
31 if ((uintptr_t)sa->sa_handler > 1UL) {
32 a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
33 1UL<<(sig-1)%(8*sizeof(long)));
34
35 /* If pthread_create has not yet been called,
36 * implementation-internal signals might not
37 * yet have been unblocked. They must be
38 * unblocked before any signal handler is
39 * installed, so that an application cannot
40 * receive an illegal sigset_t (with them
41 * blocked) as part of the ucontext_t passed
42 * to the signal handler. */
43 if (!libc.threaded && !unmask_done) {
44 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
45 SIGPT_SET, 0, _NSIG/8);
46 unmask_done = 1;
47 }
48
49 if (!(sa->sa_flags & SA_RESTART)) {
50 a_store(&__eintr_valid_flag, 1);
51 }
52 }
53 /* Changing the disposition of SIGABRT to anything but
54 * SIG_DFL requires a lock, so that it cannot be changed
55 * while abort is terminating the process after simply
56 * calling raise(SIGABRT) failed to do so. */
57 if (sa->sa_handler != SIG_DFL && sig == SIGABRT) {
58 __block_all_sigs(&set);
59 LOCK(__abort_lock);
60 }
61 ksa.handler = sa->sa_handler;
62 ksa.flags = sa->sa_flags | SA_RESTORER;
63 ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
64 memcpy(&ksa.mask, &sa->sa_mask, _NSIG/8);
65 }
66 int r = __syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, _NSIG/8);
67 if (sig == SIGABRT && sa && sa->sa_handler != SIG_DFL) {
68 UNLOCK(__abort_lock);
69 __restore_sigs(&set);
70 }
71 if (old && !r) {
72 old->sa_handler = ksa_old.handler;
73 old->sa_flags = ksa_old.flags;
74 memcpy(&old->sa_mask, &ksa_old.mask, _NSIG/8);
75 }
76 return __syscall_ret(r);
77 }
78
__sigaction(int sig,const struct sigaction * restrict sa,struct sigaction * restrict old)79 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
80 {
81 if (sig-32U < 3 || sig-1U >= _NSIG-1) {
82 errno = EINVAL;
83 return -1;
84 }
85 return __libc_sigaction(sig, sa, old);
86 }
87
88 weak_alias(__sigaction, sigaction);
89