/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2005 Mark Santcroos <marks@freebsd.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <sys/param.h>
#include <sys/mount.h>

#include <ufs/ufs/dinode.h>
#include <ufs/ffs/fs.h>

#include <errno.h>
#include <ftw.h>
#include <libufs.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void     find_inum(char *path);
static void     usage(void);
static int      compare_function(const char *, const struct stat *,
                    int, struct FTW *);
static int      find_snapshot(struct statfs *sfs);

static int      verbose;
static int      cont_search;
static uint32_t inode;

int
main(int argc, char **argv)
{
        char *path;
        struct stat st;
        struct statfs *mntbuf;
        int all = 0, ch, done = 0, fscount, n;

        while ((ch = getopt(argc, argv, "adv")) != -1) {
                switch (ch) {
                case 'a':
                        all++;
                        break;
                case 'd':
                        /* continue to search when matching inode is found 
                         * this feature is not documented */
                        cont_search++;
                        break;
                case 'v':
                        verbose++;
                        break;
                default:
                        usage();
                }
        }

        argc -= optind;
        argv += optind;

        if ((all == 0 && argc != 1) || (all == 1 && argc > 0))
                usage();

        if (!all) {
                char resolved[PATH_MAX];

                path = *argv;
                /*
                 * mount(8) use realpath(3) before mounting file system,
                 * so let's do the same with the given path.
                 */
                if (realpath(path, resolved) == NULL || /* can create full path */
                    stat(resolved, &st) == -1 ||        /* is it stat'able */
                    !S_ISDIR(st.st_mode)) {             /* is it a directory */
                        usage();
                }
                path = resolved;
        }

        fscount = getmntinfo(&mntbuf, MNT_WAIT);
        for (n = 0; n < fscount; n++) {
                if (!strncmp(mntbuf[n].f_fstypename, "ufs", 3)) {
                        if (all || strcmp(path, mntbuf[n].f_mntonname) == 0) {
                                find_snapshot(&mntbuf[n]);
                                done++;
                        }
                }
        }

        if (done == 0)
                usage();

        return (0);
}

static int
find_snapshot(struct statfs *sfs)
{
        struct uufsd disk;
        int j, snapcount = 0;

        if (ufs_disk_fillout(&disk, sfs->f_mntfromname) == -1)
                perror("ufs_disk_fillout");

        if (verbose)
                printf("%s mounted on %s\n", disk.d_name, disk.d_fs.fs_fsmnt);

        for (j = 0; j < FSMAXSNAP; j++) {
                if (disk.d_fs.fs_snapinum[j]) {
                        inode = disk.d_fs.fs_snapinum[j];
                        find_inum(sfs->f_mntonname);
                        snapcount++;
                }
        }

        if (!snapcount && verbose)
                printf("\tno snapshots found\n");
                                
        return 0;
}

static int
compare_function(const char *path, const struct stat *st, int flags,
    struct FTW * ftwv __unused)
{

        if (flags == FTW_F && st->st_ino == inode) {
                if (verbose)
                        printf("\tsnapshot ");
                printf("%s", path);
                if (verbose)
                        printf(" (inode %ju)", (uintmax_t)st->st_ino);
                printf("\n");
                if (!cont_search)
                        return (EEXIST);
        }

        return (0);
}

static void
find_inum(char *path)
{
        int ret;

        ret = nftw(path, compare_function, 1, FTW_PHYS|FTW_MOUNT);
        if (ret != EEXIST && ret != 0) {
                perror("ftw");
                exit(ret);
        }
}

static void
usage(void)
{

        printf("usage: snapinfo [-v] -a\n");
        printf("       snapinfo [-v] mountpoint\n");
        exit(1);
}