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 void __restore(), __restore_rt();
  10
  11 static int unmask_done;
  12 static unsigned long handler_set[_NSIG/(8*sizeof(long))];
  13
  14 void __get_handler_set(sigset_t *set)
  15 {
  16         memcpy(set, handler_set, sizeof handler_set);
  17 }
  18
  19 int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
  20 {
  21         struct k_sigaction ksa, ksa_old;
  22         if (sig >= (unsigned)_NSIG) {
  23                 errno = EINVAL;
  24                 return -1;
  25         }
  26         if (sa) {
  27                 if ((uintptr_t)sa->sa_handler > 1UL) {
  28                         a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
  29                                 1UL<<(sig-1)%(8*sizeof(long)));
  30
  31                         /* If pthread_create has not yet been called,
  32                          * implementation-internal signals might not
  33                          * yet have been unblocked. They must be
  34                          * unblocked before any signal handler is
  35                          * installed, so that an application cannot
  36                          * receive an illegal sigset_t (with them
  37                          * blocked) as part of the ucontext_t passed
  38                          * to the signal handler. */
  39                         if (!libc.threaded && !unmask_done) {
  40                                 __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
  41                                         SIGPT_SET, 0, _NSIG/8);
  42                                 unmask_done = 1;
  43                         }
  44                 }
  45                 ksa.handler = sa->sa_handler;
  46                 ksa.flags = sa->sa_flags | SA_RESTORER;
  47                 ksa.restorer = (sa->sa_flags & SA_SIGINFO) ? __restore_rt : __restore;
  48                 memcpy(&ksa.mask, &sa->sa_mask, sizeof ksa.mask);
  49         }
  50         if (syscall(SYS_rt_sigaction, sig, sa?&ksa:0, old?&ksa_old:0, sizeof ksa.mask))
  51                 return -1;
  52         if (old) {
  53                 old->sa_handler = ksa_old.handler;
  54                 old->sa_flags = ksa_old.flags;
  55                 memcpy(&old->sa_mask, &ksa_old.mask, sizeof ksa_old.mask);
  56         }
  57         return 0;
  58 }
  59
  60 int __sigaction(int sig, const struct sigaction *restrict sa, struct sigaction *restrict old)
  61 {
  62         if (sig-32U < 3) {
  63                 errno = EINVAL;
  64                 return -1;
  65         }
  66         return __libc_sigaction(sig, sa, old);
  67 }
  68
  69 weak_alias(__sigaction, sigaction);