Doing a "ssh user@node 'ldpd -d'" was making the SSH session hang. In
the original OpenBSD's ldpd(8) daemon, the daemon function takes care
of connecting stdin/stdout/stderr to /dev/null. In the FRR port, this
only happens in the frr_run() function, after all children have been
forked. Ideally we could try to rearrange libfrr.c and ldpd.c in a way
that start_child() is called only after the parent connects the standard
I/O streams to /dev/null. But since this issue needs an immediate
fix, let's do this workaround for now. Note: even when running on the
foreground, all log messages from the child processes are sent to the
parent process, which then prints the messages to stdout/stderr and/or
to a log file.
Reported-by: Martin Winter <mwinter@opensourcerouting.org>
Signed-off-by: Renato Westphal <renato@opensourcerouting.org>
start_child(enum ldpd_process p, char *argv0, int fd_async, int fd_sync)
{
char *argv[3];
- int argc = 0;
+ int argc = 0, nullfd;
pid_t pid;
switch (pid = fork()) {
return (pid);
}
+ nullfd = open("/dev/null", O_RDONLY | O_NOCTTY);
+ dup2(nullfd, 0);
+ dup2(nullfd, 1);
+ dup2(nullfd, 2);
+ close(nullfd);
+
if (dup2(fd_async, LDPD_FD_ASYNC) == -1)
fatal("cannot setup imsg async fd");
if (dup2(fd_sync, LDPD_FD_SYNC) == -1)