From patchwork Wed Sep 21 13:25:10 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 15842 Received: (qmail 112328 invoked by alias); 21 Sep 2016 13:25:25 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 112315 invoked by uid 89); 21 Sep 2016 13:25:24 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.2 required=5.0 tests=BAYES_00, KAM_INFOUSMEBIZ, RP_MATCHES_RCVD, SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=UD:stdarg.h, stdargh, stdarg.h, H*M:4132 X-HELO: mx1.redhat.com Subject: Re: [PATCH] Add test case for O_TMPFILE handling in open, openat To: "Carlos O'Donell" References: <449c3862-29e1-fce6-34e3-f6362153783f@redhat.com> <28f0abf7-c956-ea94-d11e-d8f24f72bc90@redhat.com> Cc: GNU C Library From: Florian Weimer Message-ID: Date: Wed, 21 Sep 2016 15:25:10 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <28f0abf7-c956-ea94-d11e-d8f24f72bc90@redhat.com> On 09/21/2016 01:53 PM, Florian Weimer wrote: > On 09/20/2016 09:26 PM, Carlos O'Donell wrote: >> On 09/20/2016 02:51 PM, Florian Weimer wrote: >>> I noticed that we do not seem to have a test case for O_TMPFILE >>> handling. >>> >>> I have tested the attached patch with recent kernels and Red Hat's >>> 3.10 kernels (where it prints UNSUPPORTED). I verified that >>> probe_path works as intended with a vfat file system (which does not >>> support O_TMPFILE even on a supported kernel). >> >> The actual details of the patch look good to me, so OK conditional >> on more comments about: >> * What is being tested. >> * Is it sufficient? >> * If not, where might we improve in the future? >> * Under what conditions do we mark as UNSUPPORTED? > > I tried to add a test for linkat, but it appears to be broken at the > kernel level: > > > > I'll probably commit the glibc test without the linkat bits. And here is what I've committed. Thanks, Florian Add test case for O_TMPFILE handling in open, openat Also put xasprintf into test-skeleton.c (written in such a way that including is not needed). 2016-09-21 Florian Weimer * test-skeleton.c (xasprintf): Add function. * io/tst-open-tmpfile.c: New test. * io/Makefile (tests): Add it. diff --git a/io/Makefile b/io/Makefile index deb6100..f5977af 100644 --- a/io/Makefile +++ b/io/Makefile @@ -71,7 +71,8 @@ tests := test-utime test-stat test-stat2 test-lfs tst-getcwd \ tst-renameat tst-fchownat tst-fchmodat tst-faccessat \ tst-symlinkat tst-linkat tst-readlinkat tst-mkdirat \ tst-mknodat tst-mkfifoat tst-ttyname_r bug-ftw5 \ - tst-posix_fallocate tst-fts tst-fts-lfs + tst-posix_fallocate tst-fts tst-fts-lfs \ + tst-open-tmpfile ifeq ($(run-built-tests),yes) tests-special += $(objpfx)ftwtest.out diff --git a/io/tst-open-tmpfile.c b/io/tst-open-tmpfile.c new file mode 100644 index 0000000..9af1875 --- /dev/null +++ b/io/tst-open-tmpfile.c @@ -0,0 +1,216 @@ +/* Test open and openat with O_TMPFILE. + Copyright (C) 2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +/* This test verifies that open and openat work as expected, i.e. they + create a deleted file with the requested file mode. */ + +#include +#include +#include +#include +#include +#include +#include +#include + +static int do_test (void); + +#define TEST_FUNCTION do_test () +#include "../test-skeleton.c" + +#ifdef O_TMPFILE +typedef int (*wrapper_func) (const char *, int, mode_t); + +/* Error-checking wrapper for the open function, compatible with the + wrapper_func type. */ +static int +wrap_open (const char *path, int flags, mode_t mode) +{ + int ret = open (path, flags, mode); + if (ret < 0) + { + printf ("error: open (\"%s\", 0x%x, 0%03o): %m\n", path, flags, mode); + exit (1); + } + return ret; +} + +/* Error-checking wrapper for the openat function, compatible with the + wrapper_func type. */ +static int +wrap_openat (const char *path, int flags, mode_t mode) +{ + int ret = openat (AT_FDCWD, path, flags, mode); + if (ret < 0) + { + printf ("error: openat (\"%s\", 0x%x, 0%03o): %m\n", path, flags, mode); + exit (1); + } + return ret; +} + +/* Return true if FD is flagged as deleted in /proc/self/fd, false if + not. */ +static bool +is_file_deteted (int fd) +{ + char *proc_fd_path = xasprintf ("/proc/self/fd/%d", fd); + char file_path[4096]; + ssize_t file_path_length + = readlink (proc_fd_path, file_path, sizeof (file_path)); + if (file_path_length < 0) + { + printf ("error: readlink (\"%s\"): %m", proc_fd_path); + free (proc_fd_path); + exit (1); + } + free (proc_fd_path); + if (file_path_length == sizeof (file_path)) + { + printf ("error: path in /proc resolves to overlong file name: %.*s\n", + (int) file_path_length, file_path); + exit (1); + } + const char *deleted = " (deleted)"; + if (file_path_length < strlen (deleted)) + { + printf ("error: path in /proc is too short: %.*s\n", + (int) file_path_length, file_path); + exit (1); + } + return memcmp (file_path + file_path_length - strlen (deleted), + deleted, strlen (deleted)) == 0; +} + +/* Check open/openat (as specified by OP and WRAPPER) with a specific + PATH/FLAGS/MODE combination. */ +static void +check_wrapper_flags_mode (const char *op, wrapper_func wrapper, + const char *path, int flags, mode_t mode) +{ + int fd = wrapper (path, flags | O_TMPFILE, mode); + struct stat64 st; + if (fstat64 (fd, &st) != 0) + { + printf ("error: fstat64: %m\n"); + exit (1); + } + + /* Verify that the mode was correctly processed. */ + int actual_mode = st.st_mode & 0777; + if (actual_mode != mode) + { + printf ("error: unexpected mode; expected 0%03o, actual 0%03o\n", + mode, actual_mode); + exit (1); + } + + /* Check that the file is marked as deleted in /proc. */ + if (!is_file_deteted (fd)) + { + printf ("error: path in /proc is not marked as deleted\n"); + exit (1); + } + + close (fd); +} + +/* Check OP/WRAPPER with various flags at a specific PATH and + MODE. */ +static void +check_wrapper_mode (const char *op, wrapper_func wrapper, + const char *path, mode_t mode) +{ + check_wrapper_flags_mode (op, wrapper, path, O_WRONLY, mode); + check_wrapper_flags_mode (op, wrapper, path, O_WRONLY | O_EXCL, mode); + check_wrapper_flags_mode (op, wrapper, path, O_RDWR, mode); + check_wrapper_flags_mode (op, wrapper, path, O_RDWR | O_EXCL, mode); +} + +/* Check open/openat with varying permissions. */ +static void +check_wrapper (const char *op, wrapper_func wrapper, + const char *path) +{ + printf ("info: testing %s at: %s\n", op, path); + check_wrapper_mode (op, wrapper, path, 0); + check_wrapper_mode (op, wrapper, path, 0640); + check_wrapper_mode (op, wrapper, path, 0600); + check_wrapper_mode (op, wrapper, path, 0755); + check_wrapper_mode (op, wrapper, path, 0750); +} + +/* Verify that the directory at PATH supports O_TMPFILE. Exit with + status 77 (unsupported) if the kernel does not support O_TMPFILE. + Even with kernel support, not all file systems O_TMPFILE, so return + true if the directory supports O_TMPFILE, false if not. */ +static bool +probe_path (const char *path) +{ + int fd = openat (AT_FDCWD, path, O_TMPFILE | O_RDWR, 0); + if (fd < 0) + { + if (errno == EISDIR) + /* The system does not support O_TMPFILE. */ + { + printf ("info: kernel does not support O_TMPFILE\n"); + exit (77); + } + if (errno == EOPNOTSUPP) + { + printf ("info: path does not support O_TMPFILE: %s\n", path); + return false; + } + printf ("error: openat (\"%s\", O_TMPFILE | O_RDWR): %m\n", path); + exit (1); + } + close (fd); + return true; +} + +static int +do_test (void) +{ + umask (0); + const char *paths[] = { ".", "/dev/shm", "/tmp", + getenv ("TEST_TMPFILE_PATH"), + NULL }; + bool supported = false; + for (int i = 0; paths[i] != NULL; ++i) + if (probe_path (paths[i])) + { + supported = true; + check_wrapper ("open", wrap_open, paths[i]); + check_wrapper ("openat", wrap_openat, paths[i]); + } + + if (!supported) + return 77; + + return 0; +} + +#else /* !O_TMPFILE */ + +static int +do_test (void) +{ + return 77; +} + +#endif /* O_TMPFILE */ diff --git a/test-skeleton.c b/test-skeleton.c index 913a335..65a3818 100644 --- a/test-skeleton.c +++ b/test-skeleton.c @@ -33,6 +33,7 @@ #include #include #include +#include /* The test function is normally called `do_test' and it is called with argc and argv as the arguments. We nevertheless provide the @@ -115,6 +116,20 @@ xrealloc (void *p, size_t n) return result; } +/* Call asprintf with error checking. */ +__attribute__ ((always_inline, format (printf, 1, 2))) +static __inline__ char * +xasprintf (const char *format, ...) +{ + char *result; + if (asprintf (&result, format, __builtin_va_arg_pack ()) < 0) + { + printf ("error: asprintf: %m\n"); + exit (1); + } + return result; +} + /* Write a message to standard output. Can be used in signal handlers. */ static void