CLOEXEC: use open(CLOEXEC) if exist; do not check fcntl(FD_CLOEXEC) failure

    text           data     bss     dec     hex filename
-    370              0       0     370     172 libc/misc/dirent/opendir.o
+    366              0       0     366     16e libc/misc/dirent/opendir.o
-    375              4       0     379     17b libc/pwd_grp/lckpwdf.o
+    356              4       0     360     168 libc/pwd_grp/lckpwdf.o
-    248              0       0     248      f8 librt/shm.o
+    209              0       0     209      d1 librt/shm.o

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 42 insertions, 44 deletions

diff --git a/libc/misc/dirent/opendir.c b/libc/misc/dirent/opendir.c
index fa07d0052..70b30658e 100644
--- a/libc/misc/dirent/opendir.c
+++ b/libc/misc/dirent/opendir.c
@@ -81,28 +81,31 @@ DIR *opendir(const char *name)
 	}
 # define O_DIRECTORY 0
 #endif
-	if ((fd = open(name, O_RDONLY|O_NDELAY|O_DIRECTORY)) < 0)
+#ifndef O_CLOEXEC
+# define O_CLOEXEC 0
+#endif
+	fd = open(name, O_RDONLY|O_NDELAY|O_DIRECTORY|O_CLOEXEC);
+	if (fd < 0)
 		return NULL;
 
 	/* Note: we should check to make sure that between the stat() and open()
 	 * call, 'name' didnt change on us, but that's only if O_DIRECTORY isnt
 	 * defined and since Linux has supported it for like ever, i'm not going
 	 * to worry about it right now (if ever). */
-	if (fstat(fd, &statbuf) < 0)
-		goto close_and_ret;
-
-	/* According to POSIX, directory streams should be closed when
-	 * exec. From "Anna Pluzhnikov" <besp@midway.uchicago.edu>.
-	 */
-	if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0) {
+	if (fstat(fd, &statbuf) < 0) {
 		int saved_errno;
-close_and_ret:
 		saved_errno = errno;
 		close(fd);
 		__set_errno(saved_errno);
 		return NULL;
 	}
 
+	/* According to POSIX, directory streams should be closed when
+	 * exec. From "Anna Pluzhnikov" <besp@midway.uchicago.edu>.
+	 */
+	if (O_CLOEXEC == 0)
+		fcntl(fd, F_SETFD, FD_CLOEXEC);
+
 	ptr = fd_to_DIR(fd, statbuf.st_blksize);
 	if (!ptr) {
 		close(fd);
diff --git a/libc/misc/utmp/utent.c b/libc/misc/utmp/utent.c
index f0700af21..7d8a2d3c1 100644
--- a/libc/misc/utmp/utent.c
+++ b/libc/misc/utmp/utent.c
@@ -34,24 +34,29 @@ static const char *static_ut_name = default_file_name;
 static void __setutent(void)
 {
     if (static_fd < 0) {
-	static_fd = open(static_ut_name, O_RDWR);
+#ifndef O_CLOEXEC
+# define O_CLOEXEC 0
+#endif
+	static_fd = open(static_ut_name, O_RDWR | O_CLOEXEC);
 	if (static_fd < 0) {
-	    static_fd = open(static_ut_name, O_RDONLY);
+	    static_fd = open(static_ut_name, O_RDONLY | O_CLOEXEC);
 	    if (static_fd < 0) {
 		return; /* static_fd remains < 0 */
 	    }
 	}
-	/* Make sure the file will be closed on exec()  */
-	fcntl(static_fd, F_SETFD, FD_CLOEXEC);
-	// thus far, {G,S}ETFD only has this single flag,
-	// and setting it never fails.
-	//int ret = fcntl(static_fd, F_GETFD, 0);
-	//if (ret >= 0) {
-	//    ret = fcntl(static_fd, F_SETFD, ret | FD_CLOEXEC);
-	//}
-	//if (ret < 0) {
-	//    static_fd = -1;
-	//}
+	if (O_CLOEXEC == 0) {
+	    /* Make sure the file will be closed on exec()  */
+	    fcntl(static_fd, F_SETFD, FD_CLOEXEC);
+	    // thus far, {G,S}ETFD only has this single flag,
+	    // and setting it never fails.
+	    //int ret = fcntl(static_fd, F_GETFD, 0);
+	    //if (ret >= 0) {
+	    //    ret = fcntl(static_fd, F_SETFD, ret | FD_CLOEXEC);
+	    //}
+	    //if (ret < 0) {
+	    //    static_fd = -1;
+	    //}
+	}
 	return;
     }
     lseek(static_fd, 0, SEEK_SET);
diff --git a/libc/pwd_grp/lckpwdf.c b/libc/pwd_grp/lckpwdf.c
index c0c8f0d90..68c46e02c 100644
--- a/libc/pwd_grp/lckpwdf.c
+++ b/libc/pwd_grp/lckpwdf.c
@@ -28,17 +28,6 @@
 #include <paths.h>
 #include <shadow.h>
 
-/* Experimentally off - libc_hidden_proto(memset) */
-/* libc_hidden_proto(open) */
-/* libc_hidden_proto(fcntl) */
-/* libc_hidden_proto(close) */
-/* libc_hidden_proto(sigfillset) */
-/* libc_hidden_proto(sigaction) */
-/* libc_hidden_proto(sigprocmask) */
-/* libc_hidden_proto(sigaddset) */
-/* libc_hidden_proto(sigemptyset) */
-/* libc_hidden_proto(alarm) */
-
 /* How long to wait for getting the lock before returning with an error.  */
 #define TIMEOUT 15 /* sec */
 
@@ -56,7 +45,6 @@ static void noop_handler (int __sig);
 int
 lckpwdf (void)
 {
-  int flags;
   sigset_t saved_set;			/* Saved set of caught signals.  */
   struct sigaction saved_act;		/* Saved signal action.  */
   sigset_t new_set;			/* New set of caught signals.  */
@@ -72,16 +60,18 @@ lckpwdf (void)
   /* Prevent problems caused by multiple threads.  */
   __UCLIBC_MUTEX_LOCK(mylock);
 
-  lock_fd = open (_PATH_PASSWD, O_WRONLY);
+#ifndef O_CLOEXEC
+# define O_CLOEXEC 0
+#endif
+  lock_fd = open (_PATH_PASSWD, O_WRONLY | O_CLOEXEC);
   if (lock_fd == -1) {
     /* Cannot create lock file.  */
-	goto DONE;
+    goto DONE;
   }
-
   /* Make sure file gets correctly closed when process finished.  */
-  flags = fcntl (lock_fd, F_GETFD);
-  flags |= FD_CLOEXEC;
-  fcntl (lock_fd, F_SETFD, flags);
+  if (O_CLOEXEC == 0)
+    fcntl (lock_fd, F_SETFD, FD_CLOEXEC);
+
   /* Now we have to get exclusive write access.  Since multiple
      process could try this we won't stop when it first fails.
      Instead we set a timeout for the system call.  Once the timer
@@ -91,7 +81,7 @@ lckpwdf (void)
 
      It is important that we don't change the signal state.  We must
      restore the old signal behaviour.  */
-  memset (&new_act, '\0', sizeof (struct sigaction));
+  memset (&new_act, '\0', sizeof (new_act));
   new_act.sa_handler = noop_handler;
   __sigfillset (&new_act.sa_mask);
 
@@ -125,7 +115,7 @@ lckpwdf (void)
   if (result < 0) {
     close(lock_fd);
     lock_fd = -1;
-	goto DONE;
+    goto DONE;
   }
   rv = 0;
 
@@ -146,7 +136,7 @@ ulckpwdf (void)
   else
     {
       /* Prevent problems caused by multiple threads.  */
-	  __UCLIBC_MUTEX_LOCK(mylock);
+      __UCLIBC_MUTEX_LOCK(mylock);
 
       result = close (lock_fd);
 
@@ -154,7 +144,7 @@ ulckpwdf (void)
       lock_fd = -1;
 
       /* Clear mutex.  */
-	  __UCLIBC_MUTEX_UNLOCK(mylock);
+      __UCLIBC_MUTEX_UNLOCK(mylock);
     }
 
   return result;