From 6b085ba47715a3e7283ec383c1ddf0f8b14dc60c Mon Sep 17 00:00:00 2001
From: Kevin Krakauer <krakauer@google.com>
Date: Thu, 25 Mar 2021 11:58:35 -0700
Subject: [PATCH] setgid: skip tests when we can't find usable GIDs

PiperOrigin-RevId: 365092320
---
 test/syscalls/linux/setgid.cc | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/test/syscalls/linux/setgid.cc b/test/syscalls/linux/setgid.cc
index 98f8f3dfe..ce61bc36d 100644
--- a/test/syscalls/linux/setgid.cc
+++ b/test/syscalls/linux/setgid.cc
@@ -107,16 +107,7 @@ PosixErrorOr<std::pair<gid_t, gid_t>> Groups() {
   if (!capable.ValueOrDie()) {
     return PosixError(EPERM, "missing CAP_SETGID");
   }
-  gid_t gid = getegid();
-  auto cleanup1 = Setegid(gid);
-  if (!cleanup1.ok()) {
-    return cleanup1.error();
-  }
-  auto cleanup2 = Setegid(kNobody);
-  if (!cleanup2.ok()) {
-    return cleanup2.error();
-  }
-  return std::pair<gid_t, gid_t>(gid, kNobody);
+  return std::pair<gid_t, gid_t>(getegid(), kNobody);
 }
 
 class SetgidDirTest : public ::testing::Test {
@@ -132,6 +123,12 @@ class SetgidDirTest : public ::testing::Test {
     SKIP_IF(!groups.ok());
     groups_ = groups.ValueOrDie();
 
+    // Ensure we can actually use both groups.
+    auto cleanup1 = Setegid(groups_.first);
+    SKIP_IF(!cleanup1.ok());
+    auto cleanup2 = Setegid(groups_.second);
+    SKIP_IF(!cleanup2.ok());
+
     auto cleanup = Setegid(groups_.first);
     temp_dir_ = ASSERT_NO_ERRNO_AND_VALUE(
         TempPath::CreateDirWith(GetAbsoluteTestTmpdir(), 0777 /* mode */));