Check for error from dup2

Do not take correct fd as error result.

diff --git a/tools/polldaemon.c b/tools/polldaemon.c
index 82b9f2475773ff17e8c8fd2396a6852939f72e79..fe55c3b6ff2f61a11fa676d0a3f32a3e5bce6b9b 100644 (file)
--- a/tools/polldaemon.c
+++ b/tools/polldaemon.c
@@ -67,9 +67,9 @@ static int _become_daemon(struct cmd_context *cmd)
                _exit(ECMD_FAILED);
        }
 
-       if (dup2(null_fd, STDIN_FILENO)  || /* reopen stdin */
-           dup2(null_fd, STDOUT_FILENO) || /* reopen stdout */
-           dup2(null_fd, STDERR_FILENO)) { /* reopen stderr */
+       if ((dup2(null_fd, STDIN_FILENO) < 0)  || /* reopen stdin */
+           (dup2(null_fd, STDOUT_FILENO) < 0) || /* reopen stdout */
+           (dup2(null_fd, STDERR_FILENO) < 0)) { /* reopen stderr */
                log_sys_error("dup2", "redirect");
                (void) close(null_fd);
                _exit(ECMD_FAILED);