From 9ca3e8a2147b1d8d387ab38f54cca5f3082971cd Mon Sep 17 00:00:00 2001 From: =?utf8?q?J=C3=A9r=C3=A9mie=20Galarneau?= Date: Fri, 22 Nov 2019 18:54:58 -0500 Subject: [PATCH] Test: add a unit test for the fd tracker MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Jérémie Galarneau --- .gitignore | 1 + tests/unit/Makefile.am | 11 +- tests/unit/test_fd_tracker.c | 666 +++++++++++++++++++++++++++++++++++ 3 files changed, 676 insertions(+), 2 deletions(-) create mode 100644 tests/unit/test_fd_tracker.c diff --git a/.gitignore b/.gitignore index 61d7ca38f..e5b639ada 100644 --- a/.gitignore +++ b/.gitignore @@ -86,6 +86,7 @@ compile_commands.json /tests/unit/test_notification /tests/unit/test_directory_handle /tests/unit/test_relayd_backward_compat_group_by_session +/tests/unit/test_fd_tracker kernel_all_events_basic kernel_event_basic ust_global_event_wildcard diff --git a/tests/unit/Makefile.am b/tests/unit/Makefile.am index 0509d5114..5410e730e 100644 --- a/tests/unit/Makefile.am +++ b/tests/unit/Makefile.am @@ -17,12 +17,14 @@ TESTS = test_kernel_data \ test_notification \ test_directory_handle \ test_relayd_backward_compat_group_by_session \ - ini_config/test_ini_config + ini_config/test_ini_config \ + test_fd_tracker LIBTAP=$(top_builddir)/tests/utils/tap/libtap.la LIBCOMMON=$(top_builddir)/src/common/libcommon.la LIBSTRINGUTILS=$(top_builddir)/src/common/string-utils/libstring-utils.la +LIBFDTRACKER=$(top_builddir)/src/common/fd-tracker/libfd-tracker.la LIBSESSIOND_COMM=$(top_builddir)/src/common/sessiond-comm/libsessiond-comm.la LIBHASHTABLE=$(top_builddir)/src/common/hashtable/libhashtable.la LIBRELAYD=$(top_builddir)/src/common/relayd/librelayd.la @@ -33,7 +35,8 @@ noinst_PROGRAMS = test_uri test_session test_kernel_data \ test_utils_parse_size_suffix test_utils_parse_time_suffix \ test_utils_expand_path test_utils_compat_poll \ test_string_utils test_notification test_directory_handle \ - test_relayd_backward_compat_group_by_session + test_relayd_backward_compat_group_by_session \ + test_fd_tracker if HAVE_LIBLTTNG_UST_CTL noinst_PROGRAMS += test_ust_data @@ -179,3 +182,7 @@ test_notification_LDADD = $(LIBTAP) $(LIBLTTNG_CTL) $(DL_LIBS) test_relayd_backward_compat_group_by_session_SOURCES = test_relayd_backward_compat_group_by_session.c test_relayd_backward_compat_group_by_session_LDADD = $(LIBTAP) $(LIBCOMMON) $(RELAYD_OBJS) test_relayd_backward_compat_group_by_session_CPPFLAGS = $(AM_CPPFLAGS) -I$(top_srcdir)/src/bin/lttng-relayd + +# fd tracker unit test +test_fd_tracker_SOURCES = test_fd_tracker.c +test_fd_tracker_LDADD = $(LIBTAP) $(LIBFDTRACKER) $(DL_LIBS) -lurcu $(LIBCOMMON) $(LIBHASHTABLE) diff --git a/tests/unit/test_fd_tracker.c b/tests/unit/test_fd_tracker.c new file mode 100644 index 000000000..4b948b342 --- /dev/null +++ b/tests/unit/test_fd_tracker.c @@ -0,0 +1,666 @@ +/* + * Copyright (c) - 2018 Jérémie Galarneau + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by as + * published by the Free Software Foundation; only version 2 of the License. + * + * This program 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 General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +/* For error.h */ +int lttng_opt_quiet = 1; +int lttng_opt_verbose; +int lttng_opt_mi; + +/* Number of TAP tests in this file */ +#define NUM_TESTS 35 +/* 3 for stdin, stdout, and stderr */ +#define STDIO_FD_COUNT 3 +#define TRACKER_FD_LIMIT 50 +#define TMP_DIR_PATTERN "/tmp/fd-tracker-XXXXXX" + +/* + * Count of fds, beyond stdin, stderr, stdout that were open + * at the launch of the test. This allows the test to succeed when + * run by automake's test runner or valgrind which both open + * fds behind our back. + */ +int unknown_fds_count; + +const char file_contents[] = "Bacon ipsum dolor amet jerky drumstick sirloin " + "strip steak venison boudin filet mignon picanha doner shoulder. " + "Strip steak brisket alcatra, venison beef chuck cupim pastrami. " + "Landjaeger tri-tip salami leberkas ball tip, ham hock chuck sausage " + "flank jerky cupim. Pig bacon chuck pancetta andouille."; + +int fd_count(void) +{ + DIR *dir; + struct dirent *entry; + int count = 0; + + dir = opendir("/proc/self/fd"); + if (!dir) { + perror("# Failed to enumerate /proc/self/fd/ to count the number of used file descriptors"); + count = -1; + goto end; + } + + while ((entry = readdir(dir)) != NULL) { + if (!strcmp(entry->d_name, ".") || !strcmp(entry->d_name, "..")) { + continue; + } + count++; + } + /* Don't account for the file descriptor opened by opendir(). */ + count--; + closedir(dir); +end: + return count; +} + +static +void check_fd_count(int expected_count) +{ + int count = 0; + + count = fd_count(); + ok(count == expected_count, "Expected %d open file descriptors (%d are open)", + expected_count, count); +} + +static +int noop_open(void *data, int *fds) +{ + *fds = *((int *) data); + return 0; +} + +static +int noop_close(void *data, int *fds) +{ + return 0; +} + +static +void track_std_fds(struct fd_tracker *tracker) +{ + int i; + struct { int fd; const char *name; } files[] = { + { .fd = fileno(stdin), .name = "stdin" }, + { .fd = fileno(stdout), .name = "stdout" }, + { .fd = fileno(stderr), .name = "stderr" }, + }; + + for (i = 0; i < sizeof(files) / sizeof(*files); i++) { + int out_fd, ret; + + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + &files[i].name, 1, noop_open, &files[i].fd); + assert(out_fd == files[i].fd); + + ok(ret == 0, "Track unsuspendable fd %d (%s)", files[i].fd, + files[i].name); + } +} + +static +void untrack_std_fds(struct fd_tracker *tracker) +{ + int i; + struct { int fd; const char *name; } files[] = { + { .fd = fileno(stdin), .name = "stdin" }, + { .fd = fileno(stdout), .name = "stdout" }, + { .fd = fileno(stderr), .name = "stderr" }, + }; + unsigned int fds_set_to_minus_1 = 0; + + for (i = 0; i < sizeof(files) / sizeof(*files); i++) { + int fd = files[i].fd; + int ret = fd_tracker_close_unsuspendable_fd(tracker, + &files[i].fd, 1, noop_close, NULL); + + ok(ret == 0, "Untrack unsuspendable fd %d (%s)", fd, + files[i].name); + fds_set_to_minus_1 += (files[i].fd == -1); + } +} + +/* + * Basic test opening and closing three unsuspendable fds. + */ +static +void test_unsuspendable_basic(void) +{ + struct fd_tracker *tracker; + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + ok(tracker, "Created an fd tracker with a limit of %d simulateously opened file descriptors", + TRACKER_FD_LIMIT); + if (!tracker) { + return; + } + + track_std_fds(tracker); + untrack_std_fds(tracker); + + fd_tracker_destroy(tracker); +} + +static +int error_open(void *data, int *fds) +{ + return *((int *) data); +} + +static +int error_close(void *data, int *fds) +{ + return *((int *) data); +} + +/* + * Validate that user callback return values are returned to the + * caller of the fd tracker. + */ +static +void test_unsuspendable_cb_return(void) +{ + int ret, stdout_fd = fileno(stdout), out_fd = 42; + struct fd_tracker *tracker; + int expected_error = -ENETDOWN; + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + assert(tracker); + + /* The error_open callback should fail and return 'expected_error'. */ + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, error_open, &expected_error); + ok(ret == expected_error, "fd_tracker_open_unsuspendable_fd() forwards the user callback's error code"); + ok(out_fd == 42, "Output fd parameter is unaffected on error of fd_tracker_open_unsuspendable_fd()"); + + /* + * Track a valid fd since we don't want the tracker to fail with an + * invalid fd error for this test. + */ + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, noop_open, &stdout_fd); + ok(out_fd == stdout_fd, "fd_tracker_open_unsuspendable_fd() sets the output fd parameter to the newly-tracked fd's value"); + assert(!ret); + + ret = fd_tracker_close_unsuspendable_fd(tracker, + &stdout_fd, 1, error_close, &expected_error); + ok(ret == expected_error, "fd_tracker_close_unsuspendable_fd() forwards the user callback's error code"); + ret = fd_tracker_close_unsuspendable_fd(tracker, + &stdout_fd, 1, noop_close, &expected_error); + assert(!ret); + + fd_tracker_destroy(tracker); +} + +/* + * Validate that the tracker refuses to track two identical unsuspendable + * file descriptors. + */ +static +void test_unsuspendable_duplicate(void) +{ + int ret, stdout_fd = fileno(stdout), out_fd; + struct fd_tracker *tracker; + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + assert(tracker); + + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, noop_open, &stdout_fd); + assert(!ret); + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, noop_open, &stdout_fd); + ok(ret == -EEXIST, "EEXIST reported on open of an already tracked file descriptor"); + + ret = fd_tracker_close_unsuspendable_fd(tracker, + &stdout_fd, 1, noop_close, NULL); + assert(!ret); + + fd_tracker_destroy(tracker); +} + +static +int open_pipes(void *data, int *out_fds) +{ + unsigned int i; + const unsigned int pipe_count = TRACKER_FD_LIMIT / 2; + + for (i = 0; i < pipe_count; i++) { + int ret = pipe(&out_fds[i * 2]); + + if (ret) { + return -errno; + } + } + return 0; +} + +static +int close_pipes(void *data, int *fds) +{ + int i; + int *pipes = fds; + + for (i = 0; i < TRACKER_FD_LIMIT; i++) { + int ret = close(pipes[i]); + + if (ret) { + return -errno; + } + } + return 0; +} + +/* + * Validate that the tracker enforces the open file descriptor limit + * when unsuspendable file descritptors are being opened. + */ +static +void test_unsuspendable_limit(void) +{ + struct fd_tracker *tracker; + int ret, stdout_fd = fileno(stdout), out_fd; + int fds[TRACKER_FD_LIMIT]; + + /* This test assumes TRACKER_FD_LIMIT is a multiple of 2. */ + assert((TRACKER_FD_LIMIT % 2 == 0) && TRACKER_FD_LIMIT); + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + assert(tracker); + + ret = fd_tracker_open_unsuspendable_fd(tracker, fds, + NULL, TRACKER_FD_LIMIT, open_pipes, NULL); + ok(ret == 0, "File descriptor tracker allowed the user to meet its limit with unsuspendable file descritptors (%d)", + TRACKER_FD_LIMIT); + + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, noop_open, &stdout_fd); + ok(ret == -EMFILE, "EMFILE reported when exceeding the file descriptor limit while opening an unsuspendable fd"); + + ret = fd_tracker_close_unsuspendable_fd(tracker, + fds, TRACKER_FD_LIMIT, close_pipes, NULL); + assert(!ret); + + fd_tracker_destroy(tracker); +} + +/* + * Validate that the tracker refuses to track two identical unsuspendable + * file descriptors. + */ +static +void test_unsuspendable_close_untracked(void) +{ + int ret, stdout_fd = fileno(stdout), unknown_fds[2], out_fd; + struct fd_tracker *tracker; + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + if (!tracker) { + return; + } + + ret = pipe(unknown_fds); + assert(!ret); + assert(close(unknown_fds[0]) == 0); + assert(close(unknown_fds[1]) == 0); + + ret = fd_tracker_open_unsuspendable_fd(tracker, &out_fd, + NULL, 1, noop_open, &stdout_fd); + assert(!ret); + + ret = fd_tracker_close_unsuspendable_fd(tracker, + unknown_fds, 1, noop_close, NULL); + ok(ret == -EINVAL, "EINVAL reported on close of an untracked file descriptor"); + + ret = fd_tracker_close_unsuspendable_fd(tracker, + &stdout_fd, 1, noop_close, NULL); + assert(!ret); + + fd_tracker_destroy(tracker); +} + +static +int open_files(struct fd_tracker *tracker, const char *dir, unsigned int count, + struct fs_handle **handles, char **file_paths) +{ + int ret = 0; + unsigned int i; + + for (i = 0; i < count; i++) { + int ret; + char *file_path; + struct fs_handle *handle; + mode_t mode = S_IWUSR | S_IRUSR; + + ret = asprintf(&file_path, "%s/file-%u", dir, i); + assert(ret >= 0); + file_paths[i] = file_path; + + handle = fd_tracker_open_fs_handle(tracker, file_path, + O_RDWR | O_CREAT, &mode); + if (!handle) { + ret = -1; + break; + } + handles[i] = handle; + } + return ret; +} + +static +int cleanup_files(struct fd_tracker *tracker, const char *dir, + unsigned int count, struct fs_handle **handles, + char **file_paths) +{ + int ret = 0; + unsigned int i; + + for (i = 0; i < count; i++) { + char *file_path = file_paths[i]; + + if (!file_path) { + break; + } + (void) unlink(file_path); + free(file_path); + if (fs_handle_close(handles[i])) { + ret = -1; + } + } + return ret; +} + +static +void test_suspendable_limit(void) +{ + int ret; + const int files_to_create = TRACKER_FD_LIMIT * 10; + struct fd_tracker *tracker; + char tmp_path_pattern[] = TMP_DIR_PATTERN; + const char *output_dir; + char *output_files[files_to_create]; + struct fs_handle *handles[files_to_create]; + + memset(output_files, 0, sizeof(output_files)); + memset(handles, 0, sizeof(handles)); + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + if (!tracker) { + return; + } + + output_dir = mkdtemp(tmp_path_pattern); + if (!output_dir) { + diag("Failed to create temporary path of the form %s", + TMP_DIR_PATTERN); + assert(0); + } + + ret = open_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Created %d files with a limit of %d simultaneously-opened file descriptor", + files_to_create, TRACKER_FD_LIMIT); + check_fd_count(TRACKER_FD_LIMIT + STDIO_FD_COUNT + unknown_fds_count); + + ret = cleanup_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Close all opened filesystem handles"); + (void) rmdir(output_dir); + fd_tracker_destroy(tracker); +} + +static +void test_mixed_limit(void) +{ + int ret; + const int files_to_create = TRACKER_FD_LIMIT; + struct fd_tracker *tracker; + char tmp_path_pattern[] = TMP_DIR_PATTERN; + const char *output_dir; + char *output_files[files_to_create]; + struct fs_handle *handles[files_to_create]; + + memset(output_files, 0, sizeof(output_files)); + memset(handles, 0, sizeof(handles)); + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + if (!tracker) { + return; + } + + output_dir = mkdtemp(tmp_path_pattern); + if (!output_dir) { + diag("Failed to create temporary path of the form %s", + TMP_DIR_PATTERN); + assert(0); + } + + ret = open_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Created %d files with a limit of %d simultaneously-opened file descriptor", + files_to_create, TRACKER_FD_LIMIT); + diag("Check file descriptor count after opening %u files", files_to_create); + check_fd_count(TRACKER_FD_LIMIT + STDIO_FD_COUNT + unknown_fds_count); + + /* + * Open unsuspendable fds (stdin, stdout, stderr) and verify that the fd + * cap is still respected. + */ + diag("Check file descriptor count after adding %d unsuspendable fds", + STDIO_FD_COUNT); + track_std_fds(tracker); + check_fd_count(TRACKER_FD_LIMIT + unknown_fds_count); + diag("Untrack unsuspendable file descriptors"); + untrack_std_fds(tracker); + check_fd_count(TRACKER_FD_LIMIT + unknown_fds_count); + + ret = cleanup_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Close all opened filesystem handles"); + (void) rmdir(output_dir); + fd_tracker_destroy(tracker); +} + +/* + * Open more files than allowed by the fd tracker's cap and write, + * byte-by-byte, and in round-robin, a string. The goal is to force + * the fd tracker to suspend and resume the fs_handles often and + * verify that the fd cap is always respected. + * + * The content of the files is also verified at the end. + */ +static +void test_suspendable_restore(void) +{ + int ret; + const int files_to_create = TRACKER_FD_LIMIT * 10; + struct fd_tracker *tracker; + char tmp_path_pattern[] = TMP_DIR_PATTERN; + const char *output_dir; + char *output_files[files_to_create]; + struct fs_handle *handles[files_to_create]; + size_t content_index; + int handle_index; + bool write_success = true; + bool fd_cap_respected = true; + bool content_ok = true; + + memset(output_files, 0, sizeof(output_files)); + memset(handles, 0, sizeof(handles)); + + tracker = fd_tracker_create(TRACKER_FD_LIMIT); + if (!tracker) { + return; + } + + output_dir = mkdtemp(tmp_path_pattern); + if (!output_dir) { + diag("Failed to create temporary path of the form %s", + TMP_DIR_PATTERN); + assert(0); + } + + ret = open_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Created %d files with a limit of %d simultaneously-opened file descriptor", + files_to_create, TRACKER_FD_LIMIT); + diag("Check file descriptor count after opening %u files", files_to_create); + check_fd_count(TRACKER_FD_LIMIT + STDIO_FD_COUNT + unknown_fds_count); + + for (content_index = 0; content_index < sizeof(file_contents); content_index++) { + for (handle_index = 0; handle_index < files_to_create; handle_index++) { + int fd; + struct fs_handle *handle = handles[handle_index]; + const char *path = output_files[handle_index]; + + fd = fs_handle_get_fd(handle); + if (fd < 0) { + write_success = false; + diag("Failed to restore fs_handle to %s", + path); + goto skip_write; + } + + do { + ret = write(fd, file_contents + content_index, 1); + } while (ret < 0 && errno == EINTR); + + if (ret != 1) { + write_success = false; + PERROR("write() to %s failed", path); + goto skip_write; + } + + if (fd_count() > + (TRACKER_FD_LIMIT + STDIO_FD_COUNT + + unknown_fds_count)) { + fd_cap_respected = false; + } + + fs_handle_put_fd(handle); + } + } +skip_write: + ok(write_success, "Wrote reference string to %d files", + files_to_create); + ok(fd_cap_respected, "FD tracker enforced the file descriptor cap"); + + /* Validate the contents of the files. */ + for (handle_index = 0; handle_index < files_to_create; handle_index++) { + struct stat fd_stat; + const char *path = output_files[handle_index]; + char read_buf[sizeof(file_contents)]; + char *read_pos; + size_t to_read = sizeof(read_buf); + int fd; + + fd = open(path, O_RDONLY); + assert(fd >= 0); + ret = fstat(fd, &fd_stat); + assert(!ret); + if (fd_stat.st_size != sizeof(file_contents)) { + diag("Content size of file %s doesn't match, got %" PRId64 ", expected %zu", + path, (int64_t) fd_stat.st_size, + sizeof(file_contents)); + content_ok = false; + (void) close(fd); + break; + } + + read_pos = read_buf; + do { + ret = read(fd, read_pos, to_read); + if (ret > 0) { + to_read -= ret; + read_pos += ret; + } + } while (to_read && (ret < 0 && errno == EINTR)); + if (ret < 0) { + content_ok = false; + PERROR("Failed to read file %s", path); + (void) close(fd); + break; + } + + if (strcmp(file_contents, read_buf)) { + content_ok = false; + diag("File content doesn't match the expectated string"); + (void) close(fd); + break; + } + (void) close(fd); + } + ok(content_ok, "Files contain the expected content"); + ret = cleanup_files(tracker, output_dir, files_to_create, handles, + output_files); + ok(!ret, "Close all opened filesystem handles"); + (void) rmdir(output_dir); + fd_tracker_destroy(tracker); +} + +int main(int argc, char **argv) +{ + plan_tests(NUM_TESTS); + diag("File descriptor tracker unit tests"); + + rcu_register_thread(); + + unknown_fds_count = fd_count() - STDIO_FD_COUNT; + assert(unknown_fds_count >= 0); + + diag("Unsuspendable - basic"); + test_unsuspendable_basic(); + diag("Unsuspendable - callback return values"); + test_unsuspendable_cb_return(); + diag("Unsuspendable - duplicate file descriptors"); + test_unsuspendable_duplicate(); + diag("Unsuspendable - closing an untracked file descriptor"); + test_unsuspendable_close_untracked(); + diag("Unsuspendable - check that file descritptor limit is enforced"); + test_unsuspendable_limit(); + + diag("Suspendable - check that file descritptor limit is enforced"); + test_suspendable_limit(); + diag("Suspendable - restoration test"); + test_suspendable_restore(); + + diag("Mixed - check that file descritptor limit is enforced"); + test_mixed_limit(); + + rcu_unregister_thread(); + return exit_status(); +} -- 2.34.1