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