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
10static int unmask_done;
11static unsigned long handler_set[_NSIG/(8*sizeof(long))];
12
13void __get_handler_set(sigset_t *set)
14{
15	memcpy(set, handler_set, sizeof handler_set);
16}
17
18volatile int __eintr_valid_flag;
19
20int __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;
48#ifdef SA_RESTORER
49		ksa.flags |= SA_RESTORER;
50		ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
51#endif
52		memcpy(&ksa.mask, &sa->sa_mask, _NSIG/8);
53	}
54	int r = __syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, _NSIG/8);
55	if (old && !r) {
56		old->sa_handler = ksa_old.handler;
57		old->sa_flags = ksa_old.flags;
58		memcpy(&old->sa_mask, &ksa_old.mask, _NSIG/8);
59	}
60	return __syscall_ret(r);
61}
62
63int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
64{
65	unsigned long set[_NSIG/(8*sizeof(long))];
66
67	if (sig-32U < 3 || sig-1U >= _NSIG-1) {
68		errno = EINVAL;
69		return -1;
70	}
71
72	/* Doing anything with the disposition of SIGABRT requires a lock,
73	 * so that it cannot be changed while abort is terminating the
74	 * process and so any change made by abort can't be observed. */
75	if (sig == SIGABRT) {
76		__block_all_sigs(&set);
77		LOCK(__abort_lock);
78	}
79	int r = __libc_sigaction(sig, sa, old);
80	if (sig == SIGABRT) {
81		UNLOCK(__abort_lock);
82		__restore_sigs(&set);
83	}
84	return r;
85}
86
87weak_alias(__sigaction, sigaction);