[compiler-rt] [compiler-rt][rtsan] Fix failing file permissions test (PR #106095)

[Chris Apple via llvm-commits]

https://github.com/cjappl created https://github.com/llvm/llvm-project/pull/106095

This reverts:

d8d8d659685b114f31d1c42d6d18c3bc6d98b171

This test was failing with the assertion:
```
/build/buildbot/premerge-monolithic-linux/llvm-project/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp:198: Failure
Value of: st.st_mode & 0777
Expected: is equal to 420
  Actual: 384
```

My thought is that on my local machine, umask starts at 0022 (owner everything, group read, others read) and on the build machine umask starts at 0077 (owner everything, group nothing, others nothing).

To fix this bug, we need to record the delta between the existing umask and the requested file permissions. Does this seem reasonable?

>From d8d8d659685b114f31d1c42d6d18c3bc6d98b171 Mon Sep 17 00:00:00 2001
From: Chris Apple <cja-private at pm.me>
Date: Mon, 26 Aug 2024 07:16:54 -0700
Subject: [PATCH 1/2] Revert "[rtsan][compiler-rt] Disable file permissions
 test causing build failure (#106079)"

This reverts commit 11ba2eee59c6c7269b2dae27247048f828143274.
---
 .../rtsan/tests/rtsan_test_interceptors.cpp   | 32 ++++++++-----------
 1 file changed, 13 insertions(+), 19 deletions(-)

diff --git a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
index 5b88cf64612942..47c07b3e47abd7 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
@@ -184,25 +184,19 @@ TEST_F(RtsanFileTest, OpenatDiesWhenRealtime) {
   ExpectNonRealtimeSurvival(func);
 }
 
-// FIXME: This fails on the build machines, but not locally!
-// see https://github.com/llvm/llvm-project/pull/105732#issuecomment-2310286530
-// Value of: st.st_mode & 0777
-// Expected: is equal to 420
-// Actual: 384
-// TEST_F(RtsanFileTest, OpenCreatesFileWithProperMode) {
-//   const int mode = S_IRGRP | S_IROTH | S_IRUSR | S_IWUSR;
-//
-//   const int fd = open(GetTemporaryFilePath(), O_CREAT | O_WRONLY, mode);
-//   ASSERT_THAT(fd, Ne(-1));
-//   close(fd);
-//
-//   struct stat st;
-//   ASSERT_THAT(stat(GetTemporaryFilePath(), &st), Eq(0));
-//
-//   // Mask st_mode to get permission bits only
-//
-//   //ASSERT_THAT(st.st_mode & 0777, Eq(mode)); FAILED ASSERTION
-// }
+TEST_F(RtsanFileTest, OpenCreatesFileWithProperMode) {
+  const int mode = S_IRGRP | S_IROTH | S_IRUSR | S_IWUSR;
+
+  const int fd = open(GetTemporaryFilePath(), O_CREAT | O_WRONLY, mode);
+  ASSERT_THAT(fd, Ne(-1));
+  close(fd);
+
+  struct stat st;
+  ASSERT_THAT(stat(GetTemporaryFilePath(), &st), Eq(0));
+
+  // Mask st_mode to get permission bits only
+  ASSERT_THAT(st.st_mode & 0777, Eq(mode));
+}
 
 TEST_F(RtsanFileTest, CreatDiesWhenRealtime) {
   auto func = [this]() { creat(GetTemporaryFilePath(), S_IWOTH | S_IROTH); };

>From 7184fb5228bbe6585465a0b67fe959be3af4e045 Mon Sep 17 00:00:00 2001
From: Chris Apple <cja-private at pm.me>
Date: Mon, 26 Aug 2024 08:36:21 -0700
Subject: [PATCH 2/2] [compiler-rt][rtsan] Fix failing file permissions test

---
 compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
index 47c07b3e47abd7..8e55ccc1116727 100644
--- a/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
+++ b/compiler-rt/lib/rtsan/tests/rtsan_test_interceptors.cpp
@@ -185,6 +185,9 @@ TEST_F(RtsanFileTest, OpenatDiesWhenRealtime) {
 }
 
 TEST_F(RtsanFileTest, OpenCreatesFileWithProperMode) {
+  const mode_t existing_umask = umask(0);
+  umask(existing_umask);
+
   const int mode = S_IRGRP | S_IROTH | S_IRUSR | S_IWUSR;
 
   const int fd = open(GetTemporaryFilePath(), O_CREAT | O_WRONLY, mode);
@@ -195,7 +198,9 @@ TEST_F(RtsanFileTest, OpenCreatesFileWithProperMode) {
   ASSERT_THAT(stat(GetTemporaryFilePath(), &st), Eq(0));
 
   // Mask st_mode to get permission bits only
-  ASSERT_THAT(st.st_mode & 0777, Eq(mode));
+  const mode_t actual_mode = st.st_mode & 0777;
+  const mode_t expected_mode = mode & ~existing_umask;
+  ASSERT_THAT(actual_mode, Eq(expected_mode));
 }
 
 TEST_F(RtsanFileTest, CreatDiesWhenRealtime) {