Check that a file is a regular file with open(O_TRUNC).

It was possible to panic the sentry by opening a cache revalidating folder with
O_TRUNC|O_CREAT.

Avoids breaking php tests.

PiperOrigin-RevId: 280533213

1 files changed, 24 insertions, 0 deletions

diff --git a/test/syscalls/linux/open_create.cc b/test/syscalls/linux/open_create.cc
index e5a85ef9d..431733dbe 100644
--- a/test/syscalls/linux/open_create.cc
+++ b/test/syscalls/linux/open_create.cc
@@ -88,6 +88,30 @@ TEST(CreateTest, CreateExclusively) {
               SyscallFailsWithErrno(EEXIST));
 }
 
+TEST(CreateTeast, CreatWithOTrunc) {
+  std::string dirpath = JoinPath(GetAbsoluteTestTmpdir(), "truncd");
+  ASSERT_THAT(mkdir(dirpath.c_str(), 0777), SyscallSucceeds());
+  ASSERT_THAT(open(dirpath.c_str(), O_CREAT | O_TRUNC, 0666),
+              SyscallFailsWithErrno(EISDIR));
+}
+
+TEST(CreateTeast, CreatDirWithOTruncAndReadOnly) {
+  std::string dirpath = JoinPath(GetAbsoluteTestTmpdir(), "truncd");
+  ASSERT_THAT(mkdir(dirpath.c_str(), 0777), SyscallSucceeds());
+  ASSERT_THAT(open(dirpath.c_str(), O_CREAT | O_TRUNC | O_RDONLY, 0666),
+              SyscallFailsWithErrno(EISDIR));
+}
+
+TEST(CreateTeast, CreatFileWithOTruncAndReadOnly) {
+  std::string dirpath = JoinPath(GetAbsoluteTestTmpdir(), "truncfile");
+  int dirfd;
+  ASSERT_THAT(dirfd = open(dirpath.c_str(), O_RDWR | O_CREAT, 0666),
+              SyscallSucceeds());
+  ASSERT_THAT(open(dirpath.c_str(), O_CREAT | O_TRUNC | O_RDONLY, 0666),
+              SyscallSucceeds());
+  ASSERT_THAT(close(dirfd), SyscallSucceeds());
+}
+
 TEST(CreateTest, CreateFailsOnUnpermittedDir) {
   // Make sure we don't have CAP_DAC_OVERRIDE, since that allows the user to
   // always override directory permissions.