Error handling in swaylock daemonize()

Fixes #1741

1 files changed, 23 insertions, 1 deletions

diff --git a/swaylock/main.c b/swaylock/main.c
index 1d522184..4c6b44c6 100644
--- a/swaylock/main.c
+++ b/swaylock/main.c
@@ -23,12 +23,34 @@
 #include "wlr-layer-shell-unstable-v1-client-protocol.h"
 
 static void daemonize() {
+        int fds[2];
+        if (pipe(fds) != 0) {
+                wlr_log(L_ERROR, "Failed to pipe");
+                exit(1);
+        }
         if (fork() == 0) {
+                close(fds[0]);
                 int devnull = open("/dev/null", O_RDWR);
                 dup2(STDOUT_FILENO, devnull);
                 dup2(STDERR_FILENO, devnull);
-                chdir("/");
+                uint8_t success = 0;
+                if (chdir("/") != 0) {
+                        write(fds[1], &success, 1);
+                        exit(1);
+                }
+                success = 1;
+                if (write(fds[1], &success, 1) != 1) {
+                        exit(1);
+                }
+                close(fds[1]);
         } else {
+                close(fds[1]);
+                uint8_t success;
+                if (read(fds[0], &success, 1) != 1 || !success) {
+                        wlr_log(L_ERROR, "Failed to daemonize");
+                        exit(1);
+                }
+                close(fds[0]);
                 exit(0);
         }
 }