Add two more checks for buflen and numwritten. The buflen should be at least one, otherwise the 'buflen - 1' could underflow and cause trouble. The numwritten should be equal to 'buflen - 1'. The test will exit if any of these conditions aren't met.
Additionally, add more print information when a write failure occurs or a truncated write happens, providing clearer diagnostics. Signed-off-by: Chunyu Hu <[email protected]> --- Chagnes in v5: - new patch for making improve on write_file. Add more safety checks and diagnostics info in log --- tools/testing/selftests/mm/vm_util.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index ad96d19d1b85..02db3caad646 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -769,6 +769,8 @@ void write_file(const char *path, const char *buf, size_t buflen) { int fd; ssize_t numwritten; + if (buflen < 1) + ksft_exit_fail_msg("Incorrect buffer len: %zu\n", buflen); fd = open(path, O_WRONLY); if (fd == -1) @@ -777,5 +779,9 @@ void write_file(const char *path, const char *buf, size_t buflen) numwritten = write(fd, buf, buflen - 1); close(fd); if (numwritten < 1) - ksft_exit_fail_msg("Write failed\n"); + ksft_exit_fail_msg("%s write(%s) failed: %s\n", path, buf, + strerror(errno)); + if (numwritten != buflen - 1) + ksft_exit_fail_msg("%s write(%s) is truncated, expected %zu bytes, got %zd bytes\n", + path, buf, buflen - 1, numwritten); } -- 2.53.0
