diff options
| -rw-r--r-- | test/syscalls/linux/truncate.cc | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/test/syscalls/linux/truncate.cc b/test/syscalls/linux/truncate.cc index c988c6380..bfc95ed38 100644 --- a/test/syscalls/linux/truncate.cc +++ b/test/syscalls/linux/truncate.cc @@ -196,6 +196,26 @@ TEST(TruncateTest, FtruncateNonWriteable) { EXPECT_THAT(ftruncate(fd.get(), 0), SyscallFailsWithErrno(EINVAL)); } +// ftruncate(2) should succeed as long as the file descriptor is writeable, +// regardless of whether the file permissions allow writing. +TEST(TruncateTest, FtruncateWithoutWritePermission_NoRandomSave) { + // Drop capabilities that allow us to override file permissions. + ASSERT_NO_ERRNO(SetCapability(CAP_DAC_OVERRIDE, false)); + + // The only time we can open a file with flags forbidden by its permissions + // is when we are creating the file. We cannot re-open with the same flags, + // so we cannot restore an fd obtained from such an operation. + const DisableSave ds; + auto path = NewTempAbsPath(); + const FileDescriptor fd = + ASSERT_NO_ERRNO_AND_VALUE(Open(path, O_RDWR | O_CREAT, 0444)); + + // In goferfs, ftruncate may be converted to a remote truncate operation that + // unavoidably requires write permission. + SKIP_IF(IsRunningOnGvisor() && !ASSERT_NO_ERRNO_AND_VALUE(IsTmpfs(path))); + ASSERT_THAT(ftruncate(fd.get(), 100), SyscallSucceeds()); +} + TEST(TruncateTest, TruncateNonExist) { EXPECT_THAT(truncate("/foo/bar", 0), SyscallFailsWithErrno(ENOENT)); } |