stdin is always redirected to /dev/null

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.

1 files 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,