[LTP] [PATCH v2 2/2] syscalls/fanotify21: add new test checking the returned pidfd from fanotify in FAN_REPORT_PIDFD mode
Matthew Bobrowski
repnop@google.com
Tue Nov 2 11:57:57 CET 2021
A new test that performs verification on the values returned within
the struct fanotify_event_info_pidfd record when the notification
group has been intialized in FAN_REPORT_PIDFD mode.
Signed-off-by: Matthew Bobrowski <repnop@google.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
---
Changes since v1:
- Adapted do_setup() to make use of the
REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_BY_KERNEL() rather than open
coding it.
- For parsing procfs information, rather than reimplementing parsing
utility functions, make use of the existing SAFE_FILE_LINES_SCANF()
library function.
testcases/kernel/syscalls/fanotify/.gitignore | 1 +
.../kernel/syscalls/fanotify/fanotify21.c | 306 ++++++++++++++++++
2 files changed, 307 insertions(+)
create mode 100644 testcases/kernel/syscalls/fanotify/fanotify21.c
diff --git a/testcases/kernel/syscalls/fanotify/.gitignore b/testcases/kernel/syscalls/fanotify/.gitignore
index c99e6fff7..35e73b91e 100644
--- a/testcases/kernel/syscalls/fanotify/.gitignore
+++ b/testcases/kernel/syscalls/fanotify/.gitignore
@@ -18,4 +18,5 @@
/fanotify18
/fanotify19
/fanotify20
+/fanotify21
/fanotify_child
diff --git a/testcases/kernel/syscalls/fanotify/fanotify21.c b/testcases/kernel/syscalls/fanotify/fanotify21.c
new file mode 100644
index 000000000..e842dad17
--- /dev/null
+++ b/testcases/kernel/syscalls/fanotify/fanotify21.c
@@ -0,0 +1,306 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2021 Google. All Rights Reserved.
+ *
+ * Started by Matthew Bobrowski <repnop@google.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * A test which verifies whether the returned struct
+ * fanotify_event_info_pidfd in FAN_REPORT_PIDFD mode contains the
+ * expected set of information.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include "tst_test.h"
+#include "tst_safe_stdio.h"
+#include "lapi/pidfd_open.h"
+
+#ifdef HAVE_SYS_FANOTIFY_H
+#include "fanotify.h"
+
+#define BUF_SZ 4096
+#define MOUNT_PATH "fs_mnt"
+#define TEST_FILE MOUNT_PATH "/testfile"
+
+struct pidfd_fdinfo_t {
+ int pos;
+ int flags;
+ int mnt_id;
+ int pid;
+ int ns_pid;
+};
+
+struct test_case_t {
+ char *name;
+ int fork;
+ int want_pidfd_err;
+} test_cases[] = {
+ {
+ "return a valid pidfd for event created by self",
+ 0,
+ 0,
+ },
+ {
+ "return invalid pidfd for event created by terminated child",
+ 1,
+ FAN_NOPIDFD,
+ },
+};
+
+static int fanotify_fd;
+static char event_buf[BUF_SZ];
+static struct pidfd_fdinfo_t *self_pidfd_fdinfo = NULL;
+
+static struct pidfd_fdinfo_t *read_pidfd_fdinfo(int pidfd)
+{
+ char *fdinfo_path;
+ struct pidfd_fdinfo_t *pidfd_fdinfo;
+
+ pidfd_fdinfo = SAFE_MALLOC(sizeof(struct pidfd_fdinfo_t));
+
+ SAFE_ASPRINTF(&fdinfo_path, "/proc/self/fdinfo/%d", pidfd);
+ SAFE_FILE_LINES_SCANF(fdinfo_path, "pos: %d", &pidfd_fdinfo->pos);
+ SAFE_FILE_LINES_SCANF(fdinfo_path, "flags: %d", &pidfd_fdinfo->flags);
+ SAFE_FILE_LINES_SCANF(fdinfo_path, "mnt_id: %d", &pidfd_fdinfo->mnt_id);
+ SAFE_FILE_LINES_SCANF(fdinfo_path, "Pid: %d", &pidfd_fdinfo->pid);
+ SAFE_FILE_LINES_SCANF(fdinfo_path, "NSpid: %d", &pidfd_fdinfo->ns_pid);
+
+ free(fdinfo_path);
+
+ return pidfd_fdinfo;
+}
+
+static void generate_event(void)
+{
+ int fd;
+
+ /* Generate a single FAN_OPEN event on the watched object. */
+ fd = SAFE_OPEN(TEST_FILE, O_RDONLY);
+ SAFE_CLOSE(fd);
+}
+
+static void do_fork(void)
+{
+ int status;
+ pid_t child;
+
+ child = SAFE_FORK();
+ if (child == 0) {
+ SAFE_CLOSE(fanotify_fd);
+ generate_event();
+ exit(EXIT_SUCCESS);
+ }
+
+ SAFE_WAITPID(child, &status, 0);
+ if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
+ tst_brk(TBROK,
+ "child process terminated incorrectly");
+}
+
+static void do_setup(void)
+{
+ int pidfd;
+
+ SAFE_TOUCH(TEST_FILE, 0666, NULL);
+
+ /*
+ * An explicit check for FAN_REPORT_PIDFD is performed early
+ * on in the test initialization as it's a prerequisite for
+ * all test cases.
+ */
+ REQUIRE_FANOTIFY_INIT_FLAGS_SUPPORTED_BY_KERNEL(FAN_REPORT_PIDFD);
+
+ fanotify_fd = SAFE_FANOTIFY_INIT(FAN_REPORT_PIDFD, O_RDONLY);
+ SAFE_FANOTIFY_MARK(fanotify_fd, FAN_MARK_ADD, FAN_OPEN, AT_FDCWD,
+ TEST_FILE);
+
+ pidfd = pidfd_open(getpid(), 0);
+ if (pidfd < 0) {
+ tst_brk(TBROK | TERRNO,
+ "pidfd=%d, pidfd_open(%d, 0) failed",
+ pidfd, getpid());
+ }
+
+ self_pidfd_fdinfo = read_pidfd_fdinfo(pidfd);
+ if (self_pidfd_fdinfo == NULL) {
+ tst_brk(TBROK,
+ "pidfd=%d, failed to read pidfd fdinfo",
+ pidfd);
+ }
+}
+
+static void do_test(unsigned int num)
+{
+ int i = 0, len;
+ struct test_case_t *tc = &test_cases[num];
+
+ tst_res(TINFO, "Test #%d: %s", num, tc->name);
+
+ /*
+ * Generate the event in either self or a child process. Event
+ * generation in a child process is done so that the FAN_NOPIDFD case
+ * can be verified.
+ */
+ if (tc->fork)
+ do_fork();
+ else
+ generate_event();
+
+ /*
+ * Read all of the queued events into the provided event
+ * buffer.
+ */
+ len = SAFE_READ(0, fanotify_fd, event_buf, sizeof(event_buf));
+ while(i < len) {
+ struct fanotify_event_metadata *event;
+ struct fanotify_event_info_pidfd *info;
+ struct pidfd_fdinfo_t *event_pidfd_fdinfo = NULL;
+
+ event = (struct fanotify_event_metadata *)&event_buf[i];
+ info = (struct fanotify_event_info_pidfd *)(event + 1);
+
+ /*
+ * Checks ensuring that pidfd information record object header
+ * fields are set correctly.
+ */
+ if (info->hdr.info_type != FAN_EVENT_INFO_TYPE_PIDFD) {
+ tst_res(TFAIL,
+ "unexpected info_type received in info "
+ "header (expected: %d, got: %d",
+ FAN_EVENT_INFO_TYPE_PIDFD,
+ info->hdr.info_type);
+ info = NULL;
+ goto next_event;
+ } else if (info->hdr.len !=
+ sizeof(struct fanotify_event_info_pidfd)) {
+ tst_res(TFAIL,
+ "unexpected info object length "
+ "(expected: %lu, got: %d",
+ sizeof(struct fanotify_event_info_pidfd),
+ info->hdr.len);
+ info = NULL;
+ goto next_event;
+ }
+
+ /*
+ * Check if pidfd information object reported any errors during
+ * creation and whether they're expected.
+ */
+ if (info->pidfd < 0 && !tc->want_pidfd_err) {
+ tst_res(TFAIL,
+ "pidfd creation failed for pid: %u with pidfd error value "
+ "set to: %d",
+ (unsigned)event->pid,
+ info->pidfd);
+ goto next_event;
+ } else if (tc->want_pidfd_err &&
+ info->pidfd != tc->want_pidfd_err) {
+ tst_res(TFAIL,
+ "pidfd set to an unexpected error: %d for pid: %u",
+ info->pidfd,
+ (unsigned)event->pid);
+ goto next_event;
+ } else if (tc->want_pidfd_err &&
+ info->pidfd == tc->want_pidfd_err) {
+ tst_res(TPASS,
+ "pid: %u terminated before pidfd was created, "
+ "pidfd set to the value of: %d, as expected",
+ (unsigned)event->pid,
+ FAN_NOPIDFD);
+ goto next_event;
+ }
+
+ /*
+ * No pidfd errors occurred, continue with verifying pidfd
+ * fdinfo validity.
+ */
+ event_pidfd_fdinfo = read_pidfd_fdinfo(info->pidfd);
+ if (event_pidfd_fdinfo == NULL) {
+ tst_brk(TBROK,
+ "reading fdinfo for pidfd: %d "
+ "describing pid: %u failed",
+ info->pidfd,
+ (unsigned)event->pid);
+ goto next_event;
+ } else if (event_pidfd_fdinfo->pid != event->pid) {
+ tst_res(TFAIL,
+ "pidfd provided for incorrect pid "
+ "(expected pidfd for pid: %u, got pidfd for "
+ "pid: %u)",
+ (unsigned)event->pid,
+ (unsigned)event_pidfd_fdinfo->pid);
+ goto next_event;
+ } else if (memcmp(event_pidfd_fdinfo, self_pidfd_fdinfo,
+ sizeof(struct pidfd_fdinfo_t))) {
+ tst_res(TFAIL,
+ "pidfd fdinfo values for self and event differ "
+ "(expected pos: %d, flags: %x, mnt_id: %d, "
+ "pid: %d, ns_pid: %d, got pos: %d, "
+ "flags: %x, mnt_id: %d, pid: %d, ns_pid: %d",
+ self_pidfd_fdinfo->pos,
+ self_pidfd_fdinfo->flags,
+ self_pidfd_fdinfo->mnt_id,
+ self_pidfd_fdinfo->pid,
+ self_pidfd_fdinfo->ns_pid,
+ event_pidfd_fdinfo->pos,
+ event_pidfd_fdinfo->flags,
+ event_pidfd_fdinfo->mnt_id,
+ event_pidfd_fdinfo->pid,
+ event_pidfd_fdinfo->ns_pid);
+ goto next_event;
+ } else {
+ tst_res(TPASS,
+ "got an event with a valid pidfd info record, "
+ "mask: %lld, pid: %u, fd: %d, "
+ "pidfd: %d, info_type: %d, info_len: %d",
+ (unsigned long long)event->mask,
+ (unsigned)event->pid,
+ event->fd,
+ info->pidfd,
+ info->hdr.info_type,
+ info->hdr.len);
+ }
+
+next_event:
+ i += event->event_len;
+ if (event->fd >= 0)
+ SAFE_CLOSE(event->fd);
+
+ if (info && info->pidfd >= 0)
+ SAFE_CLOSE(info->pidfd);
+
+ if (event_pidfd_fdinfo)
+ free(event_pidfd_fdinfo);
+ }
+}
+
+static void do_cleanup(void)
+{
+ if (fanotify_fd >= 0)
+ SAFE_CLOSE(fanotify_fd);
+
+ if (self_pidfd_fdinfo)
+ free(self_pidfd_fdinfo);
+}
+
+static struct tst_test test = {
+ .setup = do_setup,
+ .test = do_test,
+ .tcnt = ARRAY_SIZE(test_cases),
+ .cleanup = do_cleanup,
+ .all_filesystems = 1,
+ .needs_root = 1,
+ .mntpoint = MOUNT_PATH,
+ .forks_child = 1,
+};
+
+#else
+ TST_TEST_TCONF("system doesn't have required fanotify support");
+#endif /* HAVE_SYS_FANOTIFY_H */
--
2.33.1.1089.g2158813163f-goog
/M
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