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 (sig >= (unsigned)_NSIG) {
  21                 errno = EINVAL;
  22                 return -1;
  23         }
  24         if (sa) {
  25                 if ((uintptr_t)sa->sa_handler > 1UL) {
  26                         a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
  27                                 1UL<<(sig-1)%(8*sizeof(long)));
  28
  29                         /* If pthread_create has not yet been called,
  30                          * implementation-internal signals might not
  31                          * yet have been unblocked. They must be
  32                          * unblocked before any signal handler is
  33                          * installed, so that an application cannot
  34                          * receive an illegal sigset_t (with them
  35                          * blocked) as part of the ucontext_t passed
  36                          * to the signal handler. */
  37                         if (!libc.threaded && !unmask_done) {
  38                                 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
  39                                         SIGPT_SET, 0, _NSIG/8);
  40                                 unmask_done = 1;
  41                         }
  42                 }
  43                 ksa.handler = sa->sa_handler;
  44                 ksa.flags = sa->sa_flags | SA_RESTORER;
  45                 ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
  46                 memcpy(&ksa.mask, &sa->sa_mask, sizeof ksa.mask);
  47         }
  48         if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
  49                 return -1;
  50         if (old) {
  51                 old->sa_handler = ksa_old.handler;
  52                 old->sa_flags = ksa_old.flags;
  53                 memcpy(&old->sa_mask, &ksa_old.mask, sizeof ksa_old.mask);
  54         }
  55         return 0;
  56 }
  57
  58 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
  59 {
  60         if (sig-32U < 3) {
  61                 errno = EINVAL;
  62                 return -1;
  63         }
  64         return __libc_sigaction(sig, sa, old);
  65 }
  66
  67 weak_alias(__sigaction, sigaction);