From 986bd0c7c81a441aa5c19f663aa05d3363aace26 Mon Sep 17 00:00:00 2001
From: Tom Cherry <tomcherry@google.com>
Date: Mon, 16 Dec 2019 07:36:09 -0800
Subject: [PATCH] Skip pmsg related tests if /dev/pmsg0 is not found

These test use fopen() with append which includes O_CREAT.  If these
tests are run in the 'su' SELinux domain (aka through `adb root`) then
they'll create a blank text file when opening /dev/pmsg0 if it does
not exist.  Other tests and processes will attempt to write to this
file, either succeeding (for 'su' domain processes) and wasting memory,
or failing due to SELinux and generating audits (for typical
processes).

This isn't a problem for user builds, since without `adb root`, the
tests simply fail when pmsg0 does not exist.

Test: no excess denials or /dev/pmsg0 creation when running
      liblog-unit-tests as root
Change-Id: I06e0f308c72db5a53c5f9e4a29bd23f56352c7e2
---
 liblog/tests/libc_test.cpp   |  4 ++++
 liblog/tests/liblog_test.cpp | 28 ++++++++++++++--------------
 2 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/liblog/tests/libc_test.cpp b/liblog/tests/libc_test.cpp
index 3534eb8d3..1f2626390 100644
--- a/liblog/tests/libc_test.cpp
+++ b/liblog/tests/libc_test.cpp
@@ -22,6 +22,10 @@
 TEST(libc, __pstore_append) {
 #ifdef __ANDROID__
 #ifndef NO_PSTORE
+  if (access("/dev/pmsg0", W_OK) != 0) {
+    GTEST_SKIP() << "pmsg0 not found, skipping test";
+  }
+
   FILE* fp;
   ASSERT_TRUE(NULL != (fp = fopen("/dev/pmsg0", "ae")));
   static const char message[] = "libc.__pstore_append\n";
diff --git a/liblog/tests/liblog_test.cpp b/liblog/tests/liblog_test.cpp
index a60d2df31..773bac2f0 100644
--- a/liblog/tests/liblog_test.cpp
+++ b/liblog/tests/liblog_test.cpp
@@ -160,7 +160,6 @@ static std::string popenToString(const std::string& command) {
   return ret;
 }
 
-#ifndef NO_PSTORE
 static bool isPmsgActive() {
   pid_t pid = getpid();
 
@@ -170,7 +169,6 @@ static bool isPmsgActive() {
 
   return std::string::npos != myPidFds.find(" -> /dev/pmsg0");
 }
-#endif /* NO_PSTORE */
 
 static bool isLogdwActive() {
   std::string logdwSignature =
@@ -222,16 +220,18 @@ TEST(liblog, __android_log_btwrite__android_logger_list_read) {
   log_time ts(CLOCK_MONOTONIC);
   log_time ts1(ts);
 
+  bool has_pstore = access("/dev/pmsg0", W_OK) == 0;
+
   auto write_function = [&] {
     EXPECT_LT(0, __android_log_btwrite(0, EVENT_TYPE_LONG, &ts, sizeof(ts)));
     // Check that we can close and reopen the logger
     bool logdwActiveAfter__android_log_btwrite;
     if (getuid() == AID_ROOT) {
       tested__android_log_close = true;
-#ifndef NO_PSTORE
-      bool pmsgActiveAfter__android_log_btwrite = isPmsgActive();
-      EXPECT_TRUE(pmsgActiveAfter__android_log_btwrite);
-#endif /* NO_PSTORE */
+      if (has_pstore) {
+        bool pmsgActiveAfter__android_log_btwrite = isPmsgActive();
+        EXPECT_TRUE(pmsgActiveAfter__android_log_btwrite);
+      }
       logdwActiveAfter__android_log_btwrite = isLogdwActive();
       EXPECT_TRUE(logdwActiveAfter__android_log_btwrite);
     } else if (!tested__android_log_close) {
@@ -239,10 +239,10 @@ TEST(liblog, __android_log_btwrite__android_logger_list_read) {
     }
     __android_log_close();
     if (getuid() == AID_ROOT) {
-#ifndef NO_PSTORE
-      bool pmsgActiveAfter__android_log_close = isPmsgActive();
-      EXPECT_FALSE(pmsgActiveAfter__android_log_close);
-#endif /* NO_PSTORE */
+      if (has_pstore) {
+        bool pmsgActiveAfter__android_log_close = isPmsgActive();
+        EXPECT_FALSE(pmsgActiveAfter__android_log_close);
+      }
       bool logdwActiveAfter__android_log_close = isLogdwActive();
       EXPECT_FALSE(logdwActiveAfter__android_log_close);
     }
@@ -250,10 +250,10 @@ TEST(liblog, __android_log_btwrite__android_logger_list_read) {
     ts1 = log_time(CLOCK_MONOTONIC);
     EXPECT_LT(0, __android_log_btwrite(0, EVENT_TYPE_LONG, &ts1, sizeof(ts1)));
     if (getuid() == AID_ROOT) {
-#ifndef NO_PSTORE
-      bool pmsgActiveAfter__android_log_btwrite = isPmsgActive();
-      EXPECT_TRUE(pmsgActiveAfter__android_log_btwrite);
-#endif /* NO_PSTORE */
+      if (has_pstore) {
+        bool pmsgActiveAfter__android_log_btwrite = isPmsgActive();
+        EXPECT_TRUE(pmsgActiveAfter__android_log_btwrite);
+      }
       logdwActiveAfter__android_log_btwrite = isLogdwActive();
       EXPECT_TRUE(logdwActiveAfter__android_log_btwrite);
     }