shell: close all fds > 2 after forking

socket/fcntl to set FD_CLOEXEC isn't thread-safe with async verify handlers,
and SOCK_CLOEXEC isn't portable.

3 files changed, 7 insertions, 3 deletions

diff --git a/src/fastd.c b/src/fastd.c
index 523889a..191c82d 100644
--- a/src/fastd.c
+++ b/src/fastd.c
@@ -378,7 +378,7 @@ static inline void maintenance(void) {
 }
 
 
-static void close_fds(void) {
+void fastd_close_all_fds(void) {
 	struct rlimit rl;
 	int fd, maxfd;
 
@@ -465,7 +465,7 @@ static void drop_caps(void) {
 	fastd_cap_drop();
 }
 
-/* will double fork and forward potential exit codes from the child to the parent */
+/* will double fork and wait for a status notification from the child */
 static int daemonize(void) {
 	uint8_t status = 1;
 	int pipefd[2];
@@ -562,7 +562,7 @@ int main(int argc, char *argv[]) {
 	}
 #endif
 
-	close_fds();
+	fastd_close_all_fds();
 
 	fastd_random_bytes(&ctx.randseed, sizeof(ctx.randseed), false);
 
diff --git a/src/fastd.h b/src/fastd.h
index 73c7229..2654bfd 100644
--- a/src/fastd.h
+++ b/src/fastd.h
@@ -306,6 +306,8 @@ void fastd_receive(fastd_socket_t *sock);
 
 void fastd_handle_receive(fastd_peer_t *peer, fastd_buffer_t buffer);
 
+void fastd_close_all_fds(void);
+
 bool fastd_socket_handle_binds(void);
 fastd_socket_t* fastd_socket_open(fastd_peer_t *peer, int af);
 void fastd_socket_close(fastd_socket_t *sock);
diff --git a/src/shell.c b/src/shell.c
index 3b2644b..9d03fbc 100644
--- a/src/shell.c
+++ b/src/shell.c
@@ -120,6 +120,8 @@ static bool shell_command_do_exec(const fastd_shell_command_t *command, const fa
 
 	/* child process */
 
+	fastd_close_all_fds();
+
 	if (chdir(command->dir))
 		_exit(126);