Merge "pppd: add error string for setuid" am: f1682f0e43 am: 41bdf52d58

Original change: https://android-review.googlesource.com/c/platform/external/ppp/+/2098554

Change-Id: I5bbe95ac1cda45f40f9f909481219f4f5ddc32b3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/pppd/main.c b/pppd/main.c
index 09f5a53..df4e36c 100644
--- a/pppd/main.c
+++ b/pppd/main.c
@@ -1735,10 +1735,9 @@
     /* here we are executing in the child */
 
     setgid(getgid());
-    setuid(uid);
-    if (getuid() != uid) {
-	fprintf(stderr, "pppd: setuid failed\n");
-	exit(1);
+    if (setuid(uid) < 0) {
+        fprintf(stderr, "pppd: setuid failed: %s\n", strerror(errno));
+        exit(1);
     }
     update_system_environment();
 #if defined(__ANDROID__)