sd_pid_notify_with_fds: fix computing msg_controllen

[elogind.git] / src / libelogind / sd-daemon / sd-daemon.c

diff --git a/src/libelogind/sd-daemon/sd-daemon.c b/src/libelogind/sd-daemon/sd-daemon.c
index af3dab7e4cc2f120e546a8f4ec996a18fb1c14d8..f74f44c65142ec4d31339dad400919c0b1523b25 100644 (file)
--- a/src/libelogind/sd-daemon/sd-daemon.c
+++ b/src/libelogind/sd-daemon/sd-daemon.c
@@ -315,10 +315,15 @@ _public_ int sd_is_socket_unix(int fd, int type, int listening, const char *path
 _public_ int sd_is_mq(int fd, const char *path) {
         struct mq_attr attr;
 
-        assert_return(fd >= 0, -EBADF);
+        /* Check that the fd is valid */
+        assert_return(fcntl(fd, F_GETFD) >= 0, -errno);
 
-        if (mq_getattr(fd, &attr) < 0)
+        if (mq_getattr(fd, &attr) < 0) {
+                if (errno == EBADF)
+                        /* A non-mq fd (or an invalid one, but we ruled that out above) */
+                        return 0;
                 return -errno;
+        }
 
         if (path) {
                 char fpath[PATH_MAX];
@@ -401,8 +406,9 @@ _public_ int sd_pid_notify_with_fds(pid_t pid, int unset_environment, const char
         have_pid = pid != 0 && pid != getpid();
 
         if (n_fds > 0 || have_pid) {
-                msghdr.msg_controllen = CMSG_SPACE(sizeof(int) * n_fds) +
-                                        CMSG_SPACE(sizeof(struct ucred) * have_pid);
+                /* CMSG_SPACE(0) may return value different then zero, which results in miscalculated controllen. */
+                msghdr.msg_controllen = (n_fds ? CMSG_SPACE(sizeof(int) * n_fds) : 0) +
+                                        CMSG_SPACE(sizeof(struct ucred)) * have_pid;
                 msghdr.msg_control = alloca(msghdr.msg_controllen);
 
                 cmsg = CMSG_FIRSTHDR(&msghdr);