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authorEric Andersen <andersen@codepoet.org>2002-01-02 12:10:01 +0000
committerEric Andersen <andersen@codepoet.org>2002-01-02 12:10:01 +0000
commit5572db65ce5a2d0d159ec3ba20d47934303915cb (patch)
treeecdf7d274b7518333c4924bf106baceb6747f64f /libc
parent822a5d2922336680f23a68cf203a3264c8b4d152 (diff)
Fix usleep to work correctly. Fix sleep behavior in the
presence of SIGCHLD. -Erik
Diffstat (limited to 'libc')
-rw-r--r--libc/unistd/Makefile4
-rw-r--r--libc/unistd/sleep.c112
-rw-r--r--libc/unistd/usleep.c13
3 files changed, 113 insertions, 16 deletions
diff --git a/libc/unistd/Makefile b/libc/unistd/Makefile
index d481bb5ad..12f3f6f2e 100644
--- a/libc/unistd/Makefile
+++ b/libc/unistd/Makefile
@@ -26,8 +26,8 @@ include $(TOPDIR)Rules.mak
DIRS:=
CSRC=execl.c execlp.c execv.c execvep.c execvp.c execle.c getcwd.c getopt.c \
- sleep.c getpass.c sysconf_src.c getopt_vars.c getlogin.c fpathconf.c \
- confstr.c pathconf.c
+ sleep.c usleep.c getpass.c sysconf_src.c getopt_vars.c getlogin.c \
+ fpathconf.c confstr.c pathconf.c
ifeq ($(strip $(HAS_MMU)),true)
CSRC+=daemon.c
endif
diff --git a/libc/unistd/sleep.c b/libc/unistd/sleep.c
index b6c410fb5..f67d969e3 100644
--- a/libc/unistd/sleep.c
+++ b/libc/unistd/sleep.c
@@ -1,24 +1,108 @@
+/* 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.
-#include <sys/time.h>
-#include <sys/types.h>
+ 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>
-int usleep (__useconds_t usec)
+#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)
{
- struct timeval tv;
-
- tv.tv_sec = usec / 1000000;
- tv.tv_usec = usec % 1000000;
- return(select(0, 0, 0, 0, &tv));
+ struct timespec ts = {
+ tv_sec: (long int)(sec / 1000000),
+ tv_nsec: 0
+ };
+ nanosleep(&ts, &ts);
+ return(sec-ts.tv_sec);
}
-unsigned int sleep(unsigned int sec)
+#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 timeval tv;
+ 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);
- tv.tv_sec = sec;
- tv.tv_usec = 0;
- select(0, 0, 0, 0, &tv);
- return tv.tv_sec;
+ return result;
}
+#endif
diff --git a/libc/unistd/usleep.c b/libc/unistd/usleep.c
new file mode 100644
index 000000000..25979681d
--- /dev/null
+++ b/libc/unistd/usleep.c
@@ -0,0 +1,13 @@
+#include <time.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+int usleep (__useconds_t usec)
+{
+ const struct timespec ts = {
+ tv_sec: (long int)(usec / 1000000),
+ tv_nsec: (long int) (usec % 1000000) * 1000ul };
+ return(nanosleep(&ts, NULL));
+}
+