[Qemu-devel] [PATCH 2/6] qemu-ga: avoid unconditional lockfile file descriptor leak

[Jim Meyering <jim@meyering.net>]

From: Jim Meyering <meyering@redhat.com>

Do not leak a file descriptor.
Also, do not forget to unlink the lockfile upon failed lockf.
Always close the lockfile file descriptor, taking care
to diagnose close, as well as open and write, failure.

Signed-off-by: Jim Meyering <meyering@redhat.com>
---
 qemu-ga.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/qemu-ga.c b/qemu-ga.c
index 680997e..6c6de55 100644
--- a/qemu-ga.c
+++ b/qemu-ga.c
@@ -241,12 +241,13 @@ void ga_set_response_delimited(GAState *s)
 static bool ga_open_pidfile(const char *pidfile)
 {
     int pidfd;
+    int write_err;
     char pidstr[32];

     pidfd = open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
     if (pidfd == -1 || lockf(pidfd, F_TLOCK, 0)) {
         g_critical("Cannot lock pid file, %s", strerror(errno));
-        return false;
+        goto fail;
     }

     if (ftruncate(pidfd, 0) || lseek(pidfd, 0, SEEK_SET)) {
@@ -254,7 +255,9 @@ static bool ga_open_pidfile(const char *pidfile)
         goto fail;
     }
     sprintf(pidstr, "%d", getpid());
-    if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
+    write_err = write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr);
+    if (close(pidfd) || write_err) {
+        pidfd = -1;
         g_critical("Failed to write pid file");
         goto fail;
     }
@@ -262,6 +265,9 @@ static bool ga_open_pidfile(const char *pidfile)
     return true;

 fail:
+    if (pidfd != -1) {
+        close(pidfd);
+    }
     unlink(pidfile);
     return false;
 }
-- 
1.7.10.2.520.g6a4a482