[PATCH v3 08/26] file-watcher: add --detach

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

In daemon mode, stdout and stderr are saved in $WATCHER/log.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 Documentation/git-file-watcher.txt |  2 ++
 cache.h                            |  1 +
 daemon.c                           | 30 ++++--------------------------
 file-watcher.c                     | 17 +++++++++++++++++
 setup.c                            | 25 +++++++++++++++++++++++++
 5 files changed, 49 insertions(+), 26 deletions(-)

diff --git a/Documentation/git-file-watcher.txt b/Documentation/git-file-watcher.txt
index 625a389..ec81f18 100644
--- a/Documentation/git-file-watcher.txt
+++ b/Documentation/git-file-watcher.txt
@@ -18,6 +18,8 @@ lstat(2) to detect that itself.
 
 OPTIONS
 -------
+--detach::
+	Run in background.
 
 SEE ALSO
 --------
diff --git a/cache.h b/cache.h
index 939db46..7a836b1 100644
--- a/cache.h
+++ b/cache.h
@@ -434,6 +434,7 @@ extern int set_git_dir_init(const char *git_dir, const char *real_git_dir, int);
 extern int init_db(const char *template_dir, unsigned int flags);
 
 extern void sanitize_stdfds(void);
+extern int daemonize(int *);
 
 #define alloc_nr(x) (((x)+16)*3/2)
 
diff --git a/daemon.c b/daemon.c
index 503e039..2650504 100644
--- a/daemon.c
+++ b/daemon.c
@@ -1056,11 +1056,6 @@ static void drop_privileges(struct credentials *cred)
 	/* nothing */
 }
 
-static void daemonize(void)
-{
-	die("--detach not supported on this platform");
-}
-
 static struct credentials *prepare_credentials(const char *user_name,
     const char *group_name)
 {
@@ -1102,24 +1097,6 @@ static struct credentials *prepare_credentials(const char *user_name,
 
 	return &c;
 }
-
-static void daemonize(void)
-{
-	switch (fork()) {
-		case 0:
-			break;
-		case -1:
-			die_errno("fork failed");
-		default:
-			exit(0);
-	}
-	if (setsid() == -1)
-		die_errno("setsid failed");
-	close(0);
-	close(1);
-	close(2);
-	sanitize_stdfds();
-}
 #endif
 
 static void store_pid(const char *path)
@@ -1333,9 +1310,10 @@ int main(int argc, char **argv)
 	if (inetd_mode || serve_mode)
 		return execute();
 
-	if (detach)
-		daemonize();
-	else
+	if (detach) {
+		if (daemonize(NULL))
+			die("--detach not supported on this platform");
+	} else
 		sanitize_stdfds();
 
 	if (pid_file)
diff --git a/file-watcher.c b/file-watcher.c
index 9c639ef..1e1ccad 100644
--- a/file-watcher.c
+++ b/file-watcher.c
@@ -111,7 +111,10 @@ int main(int argc, const char **argv)
 {
 	struct strbuf sb = STRBUF_INIT;
 	int i, new_nr, fd, quit = 0, nr_common;
+	int daemon = 0;
 	struct option options[] = {
+		OPT_BOOL(0, "detach", &daemon,
+			 N_("run in background")),
 		OPT_END()
 	};
 
@@ -135,6 +138,20 @@ int main(int argc, const char **argv)
 	atexit(cleanup);
 	sigchain_push_common(cleanup_on_signal);
 
+	if (daemon) {
+		int err;
+		strbuf_addf(&sb, "%s/log", socket_path);
+		err = open(sb.buf, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+		adjust_shared_perm(sb.buf);
+		if (err == -1)
+			die_errno(_("unable to create %s"), sb.buf);
+		if (daemonize(&do_not_clean_up))
+			die(_("--detach not supported on this platform"));
+		dup2(err, 1);
+		dup2(err, 2);
+		close(err);
+	}
+
 	nr_common = 1;
 	pfd_alloc = pfd_nr = nr_common;
 	pfd = xmalloc(sizeof(*pfd) * pfd_alloc);
diff --git a/setup.c b/setup.c
index 6c3f85f..757c45f 100644
--- a/setup.c
+++ b/setup.c
@@ -787,3 +787,28 @@ void sanitize_stdfds(void)
 	if (fd > 2)
 		close(fd);
 }
+
+int daemonize(int *flag)
+{
+#ifndef NO_POSIX_GOODIES
+	switch (fork()) {
+		case 0:
+			break;
+		case -1:
+			die_errno("fork failed");
+		default:
+			if (flag)
+				*flag = 1;
+			exit(0);
+	}
+	if (setsid() == -1)
+		die_errno("setsid failed");
+	close(0);
+	close(1);
+	close(2);
+	sanitize_stdfds();
+	return 0;
+#else
+	return -1;
+#endif
+}
-- 
1.8.5.2.240.g8478abd