[PATCH 1/2] stdin is always redirected to /dev/null

[Eric Wong <e@80x24.org>]

There is no reason for stdin to ever be connected to a terminal,
ensure we have a consistent stdin for iostat processes and the
like.
---
 cmogstored.c | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/cmogstored.c b/cmogstored.c
index ecfbd6e..5625775 100644
--- a/cmogstored.c
+++ b/cmogstored.c
@@ -152,12 +152,11 @@ static void dup2_null(int oldfd, int newfd, const char *errdest)
 		die_errno("dup2(/dev/null,%s) failed", errdest);
 }
 
-static void daemonize(void)
+static void daemonize(int null_fd)
 {
 	int ready_pipe[2];
 	pid_t pid;
 	ssize_t r;
-	int fd;
 
 	if (pipe(ready_pipe) < 0)
 		die_errno("pipe() failed");
@@ -191,15 +190,9 @@ static void daemonize(void)
 
 	if (chdir("/") < 0)
 		die_errno("chdir(/) failed");
-	fd = open("/dev/null", O_RDWR);
-	if (fd < 0)
-		die_errno("open(/dev/null) failed");
-
-	dup2_null(fd, STDIN_FILENO, "stdin");
-	dup2_null(fd, STDOUT_FILENO, "stdout");
-	dup2_null(fd, STDERR_FILENO, "stderr");
-	mog_close(fd);
 
+	dup2_null(null_fd, STDOUT_FILENO, "stdout");
+	dup2_null(null_fd, STDERR_FILENO, "stderr");
 	do {
 		r = write(ready_pipe[1], &pid, sizeof(pid_t));
 	} while (r < 0 && errno == EINTR);
@@ -239,6 +232,7 @@ MOG_NOINLINE static void setup(int argc, char *argv[])
 {
 	int pid_fd = -1;
 	static struct argp argp = { options, parse_opt, NULL, summary };
+	int null_fd;
 
 	mog_mnt_refresh();
 	argp_parse(&argp, argc, argv, 0, NULL, &mog_cli);
@@ -250,9 +244,16 @@ MOG_NOINLINE static void setup(int argc, char *argv[])
 
 	if (mog_cli.pidfile) pid_fd = mog_pidfile_prepare(mog_cli.pidfile);
 
+	null_fd = open("/dev/null", O_RDWR);
+	if (null_fd < 0)
+		die_errno("open(/dev/null) failed");
+	dup2_null(null_fd, STDIN_FILENO, "stdin");
+
 	/* don't daemonize if we're inheriting FDs, we're already daemonized */
 	if (mog_cli.daemonize && !getenv("CMOGSTORED_FD"))
-		daemonize();
+		daemonize(null_fd);
+
+	mog_close(null_fd);
 
 	if (pid_fd >= 0 && mog_pidfile_commit(pid_fd) < 0)
 		syslog(LOG_ERR,