lib: Attach stdout to child only if --log=stdout and stdout FD is a tty

Prior to this commit stdout of a process started in a daemon mode was
attached to a calling process.
As a result a calling process hung for infinity.

Signed-off-by: Vladislav Odintsov <vlodintsov@k2.cloud>
(cherry picked from commit 0e3c5e8e5907321b35201f0985c1d3f4a1b0e639)

diff --git a/lib/libfrr.c b/lib/libfrr.c
index 33237df5fca3a28b3f3bc6ba138d4f7c254407a7..3187d8d4b64ee34d9bc669612d8a1f3b19d8b231 100644 (file)
--- a/lib/libfrr.c
+++ b/lib/libfrr.c
@@ -1108,9 +1108,12 @@ static void frr_terminal_close(int isexit)
                 * don't redirect when stdout is set with --log stdout
                 */
                for (fd = 2; fd >= 0; fd--)
-                       if (isatty(fd) &&
-                           (fd != STDOUT_FILENO || !logging_to_stdout))
+                       if (logging_to_stdout && isatty(fd) &&
+                           fd == STDOUT_FILENO) {
+                               /* Do nothing. */
+                       } else {
                                dup2(nullfd, fd);
+                       }
                close(nullfd);
        }
 }
@@ -1196,9 +1199,12 @@ void frr_run(struct event_loop *master)
                         * stdout
                         */
                        for (fd = 2; fd >= 0; fd--)
-                               if (isatty(fd) &&
-                                   (fd != STDOUT_FILENO || !logging_to_stdout))
+                               if (logging_to_stdout && isatty(fd) &&
+                                   fd == STDOUT_FILENO) {
+                                       /* Do nothing. */
+                               } else {
                                        dup2(nullfd, fd);
+                               }
                        close(nullfd);
                }