// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2014 SUSE.  All Rights Reserved.
 *
 * Started by Jan Kara <jack@suse.cz>
 */

/*\
 * [Description]
 * Check that fanotify properly merges ignore mask of an inode and mountpoint.
 */

/*
 * This is a regression test for:
 *
 *  commit 8edc6e1688fc8f02c8c1f53a2ec4928cb1055f4d
 *  Author: Jan Kara <jack@suse.cz>
 *  Date:   Thu Nov 13 15:19:33 2014 -0800
 *
 *      fanotify: fix notification of groups with inode & mount marks
 *
 * The overlayfs test case is a regression test for:
 *
 *  commit d989903058a83e8536cc7aadf9256a47d5c173fe
 *  Author: Amir Goldstein <amir73il@gmail.com>
 *  Date:   Wed Apr 24 19:39:50 2019 +0300
 *
 *      ovl: do not generate duplicate fsnotify events for "fake" path
 */

#define _GNU_SOURCE
#include "config.h"

#include <stdio.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <errno.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/syscall.h>
#include "tst_test.h"

#ifdef HAVE_SYS_FANOTIFY_H
#include "fanotify.h"

#define EVENT_MAX 1024
/* size of the event structure, not counting name */
#define EVENT_SIZE  (sizeof(struct fanotify_event_metadata))
/* reasonable guess as to size of 1024 events */
#define EVENT_BUF_LEN        (EVENT_MAX * EVENT_SIZE)

static unsigned int fanotify_prio[] = {
	FAN_CLASS_PRE_CONTENT,
	FAN_CLASS_CONTENT,
	FAN_CLASS_NOTIF
};
#define FANOTIFY_PRIORITIES ARRAY_SIZE(fanotify_prio)

#define GROUPS_PER_PRIO 3

#define BUF_SIZE 256
static char fname[BUF_SIZE];
static int fd_notify[FANOTIFY_PRIORITIES][GROUPS_PER_PRIO];

static char event_buf[EVENT_BUF_LEN];

static const char mntpoint[] = OVL_BASE_MNTPOINT;

static int ovl_mounted;

static struct tcase {
	const char *tname;
	const char *mnt;
	int use_overlay;
} tcases[] = {
	{ "Fanotify merge mount mark", mntpoint, 0 },
	{ "Fanotify merge overlayfs mount mark", OVL_MNT, 1 },
};

static void create_fanotify_groups(void)
{
	unsigned int p, i;

	for (p = 0; p < FANOTIFY_PRIORITIES; p++) {
		for (i = 0; i < GROUPS_PER_PRIO; i++) {
			fd_notify[p][i] = SAFE_FANOTIFY_INIT(fanotify_prio[p] |
							     FAN_NONBLOCK,
							     O_RDONLY);

			/* Add mount mark for each group */
			SAFE_FANOTIFY_MARK(fd_notify[p][i],
					    FAN_MARK_ADD | FAN_MARK_MOUNT,
					    FAN_MODIFY,
					    AT_FDCWD, fname);

			/* Add ignore mark for groups with higher priority */
			if (p == 0)
				continue;

			SAFE_FANOTIFY_MARK(fd_notify[p][i],
					    FAN_MARK_ADD |
					    FAN_MARK_IGNORED_MASK |
					    FAN_MARK_IGNORED_SURV_MODIFY,
					    FAN_MODIFY, AT_FDCWD, fname);
		}
	}
}

static void cleanup_fanotify_groups(void)
{
	unsigned int i, p;

	for (p = 0; p < FANOTIFY_PRIORITIES; p++) {
		for (i = 0; i < GROUPS_PER_PRIO; i++) {
			if (fd_notify[p][i] > 0)
				SAFE_CLOSE(fd_notify[p][i]);
		}
	}
}

static void verify_event(int group, struct fanotify_event_metadata *event)
{
	if (event->mask != FAN_MODIFY) {
		tst_res(TFAIL, "group %d got event: mask %llx (expected %llx) "
			"pid=%u fd=%d", group, (unsigned long long)event->mask,
			(unsigned long long)FAN_MODIFY,
			(unsigned int)event->pid, event->fd);
	} else if (event->pid != getpid()) {
		tst_res(TFAIL, "group %d got event: mask %llx pid=%u "
			"(expected %u) fd=%d", group,
			(unsigned long long)event->mask, (unsigned int)event->pid,
			(unsigned int)getpid(), event->fd);
	} else {
		tst_res(TPASS, "group %d got event: mask %llx pid=%u fd=%d",
			group, (unsigned long long)event->mask,
			(unsigned int)event->pid, event->fd);
	}
}

/* Close all file descriptors of read events */
static void close_events_fd(struct fanotify_event_metadata *event, int buflen)
{
	while (buflen >= (int)FAN_EVENT_METADATA_LEN) {
		if (event->fd != FAN_NOFD)
			SAFE_CLOSE(event->fd);
		buflen -= (int)FAN_EVENT_METADATA_LEN;
		event++;
	}
}

static void test_fanotify(unsigned int n)
{
	int ret;
	unsigned int p, i;
	struct fanotify_event_metadata *event;
	struct tcase *tc = &tcases[n];

	tst_res(TINFO, "Test #%d: %s", n, tc->tname);

	if (tc->use_overlay && !ovl_mounted) {
		tst_res(TCONF, "overlayfs is not configured in this kernel");
		return;
	}

	sprintf(fname, "%s/tfile_%d", tc->mnt, getpid());
	SAFE_TOUCH(fname, 0644, NULL);

	create_fanotify_groups();

	/*
	 * generate sequence of events
	 */
	SAFE_FILE_PRINTF(fname, "1");

	/* First verify all groups without ignore mask got the event */
	for (i = 0; i < GROUPS_PER_PRIO; i++) {
		ret = read(fd_notify[0][i], event_buf, EVENT_BUF_LEN);
		if (ret < 0) {
			if (errno == EAGAIN) {
				tst_res(TFAIL, "group %d did not get "
					"event", i);
			}
			tst_brk(TBROK | TERRNO,
				"reading fanotify events failed");
		}
		if (ret < (int)FAN_EVENT_METADATA_LEN) {
			tst_brk(TBROK,
				"short read when reading fanotify "
				"events (%d < %d)", ret,
				(int)EVENT_BUF_LEN);
		}
		event = (struct fanotify_event_metadata *)event_buf;
		if (ret > (int)event->event_len) {
			tst_res(TFAIL, "group %d got more than one "
				"event (%d > %d)", i, ret,
				event->event_len);
		} else {
			verify_event(i, event);
		}
		close_events_fd(event, ret);
	}

	for (p = 1; p < FANOTIFY_PRIORITIES; p++) {
		for (i = 0; i < GROUPS_PER_PRIO; i++) {
			ret = read(fd_notify[p][i], event_buf, EVENT_BUF_LEN);
			if (ret > 0) {
				tst_res(TFAIL, "group %d got event",
					p*GROUPS_PER_PRIO + i);
				close_events_fd((void *)event_buf, ret);
			} else if (ret == 0) {
				tst_brk(TBROK, "zero length "
					"read from fanotify fd");
			} else if (errno != EAGAIN) {
				tst_brk(TBROK | TERRNO,
					"reading fanotify events failed");
			} else {
				tst_res(TPASS, "group %d got no event",
					p*GROUPS_PER_PRIO + i);
			}
		}
	}
	cleanup_fanotify_groups();
}

static void setup(void)
{
	ovl_mounted = TST_MOUNT_OVERLAY();
}

static void cleanup(void)
{
	cleanup_fanotify_groups();

	if (ovl_mounted)
		SAFE_UMOUNT(OVL_MNT);
}

static struct tst_test test = {
	.test = test_fanotify,
	.tcnt = ARRAY_SIZE(tcases),
	.setup = setup,
	.cleanup = cleanup,
	.needs_root = 1,
	.mount_device = 1,
	.mntpoint = mntpoint,
	.tags = (const struct tst_tag[]) {
		{"linux-git", "8edc6e1688fc"},
		{"linux-git", "d989903058a8"},
		{}
	}
};

#else
	TST_TEST_TCONF("system doesn't have required fanotify support");
#endif