nsz Git - musl/blob - src/signal/sigaction.c

   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 "ksigaction.h"
   8
   9 static int unmask_done;
  10 static unsigned long handler_set[_NSIG/(8*sizeof(long))];
  11
  12 void __get_handler_set(sigset_t *set)
  13 {
  14         memcpy(set, handler_set, sizeof handler_set);
  15 }
  16
  17 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
  18 {
  19         struct k_sigaction ksa, ksa_old;
  20         if (sa) {
  21                 if ((uintptr_t)sa->sa_handler > 1UL) {
  22                         a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
  23                                 1UL<<(sig-1)%(8*sizeof(long)));
  24
  25                         /* If pthread_create has not yet been called,
  26                          * implementation-internal signals might not
  27                          * yet have been unblocked. They must be
  28                          * unblocked before any signal handler is
  29                          * installed, so that an application cannot
  30                          * receive an illegal sigset_t (with them
  31                          * blocked) as part of the ucontext_t passed
  32                          * to the signal handler. */
  33                         if (!libc.threaded && !unmask_done) {
  34                                 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
  35                                         SIGPT_SET, 0, _NSIG/8);
  36                                 unmask_done = 1;
  37                         }
  38                 }
  39                 ksa.handler = sa->sa_handler;
  40                 ksa.flags = sa->sa_flags | SA_RESTORER;
  41                 ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
  42                 memcpy(&ksa.mask, &sa->sa_mask, sizeof ksa.mask);
  43         }
  44         if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
  45                 return -1;
  46         if (old) {
  47                 old->sa_handler = ksa_old.handler;
  48                 old->sa_flags = ksa_old.flags;
  49                 memcpy(&old->sa_mask, &ksa_old.mask, sizeof ksa_old.mask);
  50         }
  51         return 0;
  52 }
  53
  54 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
  55 {
  56         if (sig-32U < 3 || sig-1U >= _NSIG-1) {
  57                 errno = EINVAL;
  58                 return -1;
  59         }
  60         return __libc_sigaction(sig, sa, old);
  61 }
  62
  63 weak_alias(__sigaction, sigaction);