sysupgrade: print errno on failure

The error message "Failed to exec upgraded." is not very informative.
Add errno to the message to make it more useful.

Lacks SoB to avoid people merging/pushing this to master.

diff --git a/sysupgrade.c b/sysupgrade.c
index fc588b0248353137d4b81fce130d2d35d8dfa710..e6c1c959bce4ed3a786afeec1778ec43b75da585 100644 (file)
--- a/sysupgrade.c
+++ b/sysupgrade.c
@@ -19,8 +19,10 @@
 #include "sysupgrade.h"
 
 #include <ctype.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include <libubox/blobmsg.h>
@@ -100,10 +102,12 @@ void sysupgrade_exec_upgraded(const char *prefix, char *path,
                free(name);
        }
 
+       errno = 0;
+
        execvp(argv[0], argv);
 
        /* Cleanup on failure */
-       fprintf(stderr, "Failed to exec upgraded.\n");
+       fprintf(stderr, "Failed to exec upgraded: %s\n", strerror(-errno));
        unsetenv("WDTFD");
        watchdog_set_cloexec(true);
        ret = chroot(".");