commit 1a18d0530e78c6f185bddbb343310629c6c09bd8
author Treehugger Robot <android-test-infra-autosubmit@system.gserviceaccount.com> Thu Jan 16 20:50:18 2025 -0800
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Thu Jan 16 20:50:18 2025 -0800
tree d8777df26c2aaed6483525380d4bc480f21e59db
parent b197a513ee48e43393be96dac713d62cd2ac57ff
parent 09c52ca4be68141c2948492bc5ed10cc6088da87

Merge "libsnapshot: Set compile_multilib to "first"" into main

libcutils/ashmem_test.cpp

diff --git a/libcutils/ashmem_test.cpp b/libcutils/ashmem_test.cpp
index ccbb8c9..7abc370 100644
--- a/libcutils/ashmem_test.cpp
+++ b/libcutils/ashmem_test.cpp
@@ -84,6 +84,11 @@
     ASSERT_EQ(0, memcmp(region1, data.data(), size));
     EXPECT_EQ(0, munmap(region1, size));
 
+    // This part of the test forks a separate process via ASSERT_EXIT() and
+    // clears the ashmem buffer.
+    //
+    // This is to ensure that updates to the contents of the buffer are visible
+    // across processes with a reference to the buffer.
     ASSERT_EXIT(
         {
             if (!ashmem_valid(fd)) {
@@ -176,26 +181,22 @@
     const size_t size = getpagesize();
     void *region;
 
-    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ));
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_EXEC));
     TestProtDenied(fd, size, PROT_WRITE);
-    TestProtIs(fd, PROT_READ);
+    TestProtIs(fd, PROT_READ | PROT_EXEC);
     ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_READ, &region));
     EXPECT_EQ(0, munmap(region, size));
 
-    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_WRITE));
-    TestProtDenied(fd, size, PROT_READ);
-    TestProtIs(fd, PROT_WRITE);
-    ASSERT_NO_FATAL_FAILURE(TestMmap(fd, size, PROT_WRITE, &region));
-    EXPECT_EQ(0, munmap(region, size));
-
-    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
-    TestProtIs(fd, PROT_READ | PROT_WRITE);
-    ASSERT_EQ(0, ashmem_set_prot_region(fd, PROT_READ));
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE |
+                                             PROT_EXEC));
+    TestProtIs(fd, PROT_READ | PROT_WRITE | PROT_EXEC);
+    ASSERT_EQ(0, ashmem_set_prot_region(fd, PROT_READ | PROT_EXEC));
     errno = 0;
-    ASSERT_EQ(-1, ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE))
+    ASSERT_EQ(-1, ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE |
+                                         PROT_EXEC))
         << "kernel shouldn't allow adding protection bits";
     EXPECT_EQ(EINVAL, errno);
-    TestProtIs(fd, PROT_READ);
+    TestProtIs(fd, PROT_READ | PROT_EXEC);
     TestProtDenied(fd, size, PROT_WRITE);
 }
 
@@ -203,22 +204,29 @@
     unique_fd fd;
     const size_t size = getpagesize();
 
-    int protFlags[] = { PROT_READ, PROT_WRITE };
-    for (size_t i = 0; i < arraysize(protFlags); i++) {
-        ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
-        ASSERT_EXIT(
-            {
-                if (!ashmem_valid(fd)) {
-                    _exit(3);
-                } else if (ashmem_set_prot_region(fd, protFlags[i]) >= 0) {
-                    _exit(0);
-                } else {
-                    _exit(1);
-                }
-            },
-            ::testing::ExitedWithCode(0), "");
-        ASSERT_NO_FATAL_FAILURE(TestProtDenied(fd, size, protFlags[1-i]));
-    }
+    ASSERT_NO_FATAL_FAILURE(TestCreateRegion(size, fd, PROT_READ | PROT_WRITE));
+
+    // This part of the test forks a process via ASSERT_EXIT()
+    // and has the child process change the mapping permissions of the
+    // buffer to read-only.
+    //
+    // The intent of this is to ensure that updates to the buffer's
+    // mapping permissions are visible across processes that reference the
+    // buffer.
+    //
+    // In this case, the parent process attempts to map the buffer with write
+    // permission, which should fail.
+    ASSERT_EXIT(
+        {
+            if (!ashmem_valid(fd)) {
+                _exit(3);
+            } else if (ashmem_set_prot_region(fd, PROT_READ) == -1) {
+                _exit(1);
+            }
+            _exit(0);
+        },
+        ::testing::ExitedWithCode(0), "");
+    ASSERT_NO_FATAL_FAILURE(TestProtDenied(fd, size, PROT_WRITE));
 }
 
 TEST(AshmemTest, ForkMultiRegionTest) {
@@ -237,6 +245,13 @@
         EXPECT_EQ(0, munmap(region, size));
     }
 
+    // This part of the test creates a child process via ASSERT_EXIT()
+    // that clears each of the ashmem buffers that were created earlier.
+    //
+    // The intent of this is for the parent process to check each region to make
+    // sure that the updates from the child process are visible, thereby showing
+    // that updates across multiple shared buffers are visible across multiple
+    // processes.
     ASSERT_EXIT({
         for (int i = 0; i < nRegions; i++) {
             if (!ashmem_valid(fd[i])) {