Refactored sys_fork() and sys_pid() into shared util library

This fixes a bug in 116ce19b, where we didn't clear the pid cache in
become_daemon() and thus the /var/run/smbd.pid didn't match the actual
pid of the parent process.

Currently S4 will clear the pid cache on fork but doesn't yet take
advantage of the pid cache by using sys_pid() instead of the direct
get_pid().

6 files changed, 43 insertions, 35 deletions

diff --git a/lib/util/become_daemon.c b/lib/util/become_daemon.c
index 5a97b65407..3d06a4363d 100644
--- a/lib/util/become_daemon.c
+++ b/lib/util/become_daemon.c
@@ -66,10 +66,10 @@ _PUBLIC_ void close_low_fds(bool stderr_too)
  Become a daemon, discarding the controlling terminal.
 ****************************************************************************/
 
-_PUBLIC_ void become_daemon(bool Fork, bool no_process_group)
+_PUBLIC_ void become_daemon(bool do_fork, bool no_process_group)
 {
-	if (Fork) {
-		if (fork()) {
+	if (do_fork) {
+		if (sys_fork()) {
 			_exit(0);
 		}
 	}
diff --git a/lib/util/system.c b/lib/util/system.c
index 9bd1800233..9bf5de1a83 100644
--- a/lib/util/system.c
+++ b/lib/util/system.c
@@ -88,3 +88,32 @@ _PUBLIC_ struct in_addr sys_inet_makeaddr(int net, int host)
 	return in2;
 }
 
+/**************************************************************************
+ Wrapper for fork. Ensures we clear our pid cache.
+****************************************************************************/
+
+static pid_t mypid = (pid_t)-1;
+
+_PUBLIC_ pid_t sys_fork(void)
+{
+	pid_t forkret = fork();
+
+	if (forkret == (pid_t)0) {
+		/* Child - reset mypid so sys_getpid does a system call. */
+		mypid = (pid_t) -1;
+	}
+
+	return forkret;
+}
+
+/**************************************************************************
+ Wrapper for getpid. Ensures we only do a system call *once*.
+****************************************************************************/
+
+_PUBLIC_ pid_t sys_getpid(void)
+{
+	if (mypid == (pid_t)-1)
+		mypid = getpid();
+
+	return mypid;
+}
diff --git a/lib/util/util.h b/lib/util/util.h
index d3e446f488..27f94cd685 100644
--- a/lib/util/util.h
+++ b/lib/util/util.h
@@ -134,6 +134,16 @@ apparent reason.
 _PUBLIC_ struct hostent *sys_gethostbyname(const char *name);
 _PUBLIC_ struct in_addr sys_inet_makeaddr(int net, int host);
 
+/**
+ * Wrapper for fork used to invalid pid cache.
+ **/
+_PUBLIC_ pid_t sys_fork(void);
+
+/**
+ * Wrapper for getpid. Ensures we only do a system call *once*.
+ **/
+_PUBLIC_ pid_t sys_getpid(void);
+
 /* The following definitions come from lib/util/genrand.c  */
 
 /**
diff --git a/source3/Makefile.in b/source3/Makefile.in
index 7564659dd3..a403f143bb 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -339,7 +339,7 @@ UTIL_OBJ = ../lib/util/rbtree.o ../lib/util/signal.o ../lib/util/time.o \
 		   ../lib/util/util.o ../lib/util/fsusage.o \
 		   ../lib/util/params.o ../lib/util/talloc_stack.o \
 		   ../lib/util/genrand.o ../lib/util/util_net.o \
-		   ../lib/util/become_daemon.o
+		   ../lib/util/become_daemon.o ../lib/util/system.o
 
 CRYPTO_OBJ = ../lib/crypto/crc32.o ../lib/crypto/md5.o \
 			 ../lib/crypto/hmacmd5.o ../lib/crypto/arcfour.o \
diff --git a/source3/include/proto.h b/source3/include/proto.h
index faf47d3844..14241d5ce3 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -972,8 +972,6 @@ struct passwd *sys_getpwnam(const char *name);
 struct passwd *sys_getpwuid(uid_t uid);
 struct group *sys_getgrnam(const char *name);
 struct group *sys_getgrgid(gid_t gid);
-pid_t sys_fork(void);
-pid_t sys_getpid(void);
 int sys_popen(const char *command);
 int sys_pclose(int fd);
 ssize_t sys_getxattr (const char *path, const char *name, void *value, size_t size);
diff --git a/source3/lib/system.c b/source3/lib/system.c
index 8bdc9fa92b..10b55f662d 100644
--- a/source3/lib/system.c
+++ b/source3/lib/system.c
@@ -1043,35 +1043,6 @@ static char **extract_args(TALLOC_CTX *mem_ctx, const char *command)
 }
 
 /**************************************************************************
- Wrapper for fork. Ensures that mypid is reset. Used so we can write
- a sys_getpid() that only does a system call *once*.
-****************************************************************************/
-
-static pid_t mypid = (pid_t)-1;
-
-pid_t sys_fork(void)
-{
-	pid_t forkret = fork();
-
-	if (forkret == (pid_t)0) /* Child - reset mypid so sys_getpid does a system call. */
-		mypid = (pid_t) -1;
-
-	return forkret;
-}
-
-/**************************************************************************
- Wrapper for getpid. Ensures we only do a system call *once*.
-****************************************************************************/
-
-pid_t sys_getpid(void)
-{
-	if (mypid == (pid_t)-1)
-		mypid = getpid();
-
-	return mypid;
-}
-
-/**************************************************************************
  Wrapper for popen. Safer as it doesn't search a path.
  Modified from the glibc sources.
  modified by tridge to return a file descriptor. We must kick our FILE* habit