/* Implementation of the POSIX sleep function using nanosleep. Copyright (C) 1996, 1997, 1998, 1999 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <errno.h> #include <time.h> #include <signal.h> #include <unistd.h> libc_hidden_proto(sleep) libc_hidden_proto(sigaction) libc_hidden_proto(sigprocmask) //libc_hidden_proto(__sigaddset) //libc_hidden_proto(__sigemptyset) //libc_hidden_proto(__sigismember) libc_hidden_proto(nanosleep) #if 0 /* This is a quick and dirty, but not 100% compliant with * the stupid SysV SIGCHLD vs. SIG_IGN behaviour. It is * fine unless you are messing with SIGCHLD... */ unsigned int sleep (unsigned int sec) { unsigned int res; struct timespec ts = { .tv_sec = (long int) seconds, .tv_nsec = 0 }; res = nanosleep(&ts, &ts); if (res) res = (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L); return res; } #else /* We are going to use the `nanosleep' syscall of the kernel. But the kernel does not implement the sstupid SysV SIGCHLD vs. SIG_IGN behaviour for this syscall. Therefore we have to emulate it here. */ unsigned int sleep (unsigned int seconds) { struct timespec ts = { .tv_sec = (long int) seconds, .tv_nsec = 0 }; sigset_t set, oset; unsigned int result; /* This is not necessary but some buggy programs depend on this. */ if (seconds == 0) return 0; /* Linux will wake up the system call, nanosleep, when SIGCHLD arrives even if SIGCHLD is ignored. We have to deal with it in libc. We block SIGCHLD first. */ if (__sigemptyset (&set) < 0 || __sigaddset (&set, SIGCHLD) < 0 || sigprocmask (SIG_BLOCK, &set, &oset)) return -1; /* If SIGCHLD is already blocked, we don't have to do anything. */ if (!__sigismember (&oset, SIGCHLD)) { int saved_errno; struct sigaction oact; if (__sigemptyset (&set) < 0 || __sigaddset (&set, SIGCHLD) < 0) return -1; /* We get the signal handler for SIGCHLD. */ if (sigaction (SIGCHLD, (struct sigaction *) NULL, &oact) < 0) { saved_errno = errno; /* Restore the original signal mask. */ (void) sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL); __set_errno (saved_errno); return -1; } if (oact.sa_handler == SIG_IGN) { /* We should leave SIGCHLD blocked. */ result = nanosleep (&ts, &ts); saved_errno = errno; /* Restore the original signal mask. */ (void) sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL); __set_errno (saved_errno); } else { /* We should unblock SIGCHLD. Restore the original signal mask. */ (void) sigprocmask (SIG_SETMASK, &oset, (sigset_t *) NULL); result = nanosleep (&ts, &ts); } } else result = nanosleep (&ts, &ts); if (result != 0) /* Round remaining time. */ result = (unsigned int) ts.tv_sec + (ts.tv_nsec >= 500000000L); return result; } #endif libc_hidden_def(sleep)