/*
 * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@backplane.com>
 *
 * 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.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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
 * COPYRIGHT HOLDERS OR CONTRIBUTORS 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.
 *
 * $DragonFly: src/sbin/hammer/cmd_snapshot.c,v 1.7 2008/07/10 18:47:22 mneumann Exp $
 */

#include "hammer.h"

#define DEFAULT_SNAPSHOT_NAME "snap-%Y%m%d-%H%M"

static void snapshot_usage(int exit_code);
static void snapshot_add(int fd, const char *fsym, const char *tsym,
                const char *label, hammer_tid_t tid);
static void snapshot_ls(const char *path);
static void snapshot_del(int fsfd, hammer_tid_t tid);
static char *dirpart(const char *path);

/*
 * hammer snap <path> [<note>]
 *
 * Path may be a directory, softlink, or non-existent (a softlink will be
 * created).
 */
void
hammer_cmd_snap(char **av, int ac, int tostdout, int fsbase)
{
        struct hammer_ioc_synctid synctid;
        struct hammer_ioc_version version;
        char *dirpath;
        char *fsym = NULL;
        char *tsym = NULL;
        struct stat st;
        char note[64];
        int fsfd;

        if (ac == 0 || ac > 2) {
                snapshot_usage(1);
                /* not reached */
        }

        if (ac == 2)
                snprintf(note, sizeof(note), "%s", av[1]);
        else
                note[0] = 0;

        /*
         * Figure out the softlink path and directory path
         */
        if (stat(av[0], &st) < 0) {
                dirpath = dirpart(av[0]);
                tsym = strdup(av[0]);
        } else if (S_ISDIR(st.st_mode)) {
                time_t t = time(NULL);
                struct tm *tp;
                char extbuf[64];

                tp = localtime(&t);
                strftime(extbuf, sizeof(extbuf), DEFAULT_SNAPSHOT_NAME, tp);

                dirpath = strdup(av[0]);
                asprintf(&tsym, "%s/%s", dirpath, extbuf);
        } else {
                err(2, "hammer snap: File %s exists and is not a directory",
                    av[0]);
                /* not reached */
        }

        /*
         * Get a handle on some directory in the filesystem for the
         * ioctl (so it is stored in the correct PFS).
         */
        fsfd = open(dirpath, O_RDONLY);
        if (fsfd < 0) {
                err(2, "hammer snap: Cannot open directory %s", dirpath);
                /* not reached */
        }

        /*
         * Must be at least version 3 to use this command.
         */
        bzero(&version, sizeof(version));

        if (ioctl(fsfd, HAMMERIOC_GET_VERSION, &version) < 0) {
                err(2, "Unable to create snapshot");
                /* not reached */
        } else if (version.cur_version < 3) {
                errx(2, "Unable to create snapshot: This directive requires "
                        "you to upgrade\n"
                        "the filesystem to version 3.  "
                        "Use 'hammer snapshot' for legacy operation.");
                /* not reached */
        }
        HammerVersion = version.cur_version;

        /*
         * Synctid to get a transaction id for the snapshot.
         */
        bzero(&synctid, sizeof(synctid));
        synctid.op = HAMMER_SYNCTID_SYNC2;
        if (ioctl(fsfd, HAMMERIOC_SYNCTID, &synctid) < 0) {
                err(2, "hammer snap: Synctid %s failed",
                    dirpath);
                /* not reached */
        }
        if (tostdout) {
                if (strcmp(dirpath, ".") == 0 || strcmp(dirpath, "..") == 0) {
                        printf("%s/@@0x%016jx\n",
                                dirpath, (uintmax_t)synctid.tid);
                } else {
                        printf("%s@@0x%016jx\n",
                                dirpath, (uintmax_t)synctid.tid);
                }
                fsym = NULL;
                tsym = NULL;
        }

        /*
         * Contents of the symlink being created.
         */
        if (fsbase) {
                struct statfs buf;

                if (statfs(dirpath, &buf) < 0) {
                        err(2, "hammer snap: Cannot determine mount for %s",
                            dirpath);
                        /* not reached */
                }
                asprintf(&fsym, "%s/@@0x%016jx",
                         buf.f_mntonname, (uintmax_t)synctid.tid);
        } else if (strcmp(dirpath, ".") == 0 || strcmp(dirpath, "..") == 0) {
                asprintf(&fsym, "%s/@@0x%016jx",
                         dirpath, (uintmax_t)synctid.tid);
        } else {
                asprintf(&fsym, "%s@@0x%016jx",
                         dirpath, (uintmax_t)synctid.tid);
        }

        /*
         * Create the snapshot.
         */
        snapshot_add(fsfd, fsym, tsym, note, synctid.tid);
        free(dirpath);
        free(fsym);
        free(tsym);
}

/*
 * hammer snapls [<path> ...]
 *
 * If no arguments are specified snapshots for the PFS containing the
 * current directory are listed.
 */
void
hammer_cmd_snapls(char **av, int ac)
{
        int i;

        for (i = 0; i < ac; ++i)
                snapshot_ls(av[i]);
        if (ac == 0)
                snapshot_ls(".");
}

/*
 * hammer snaprm <path> ...
 * hammer snaprm <transid> ...
 * hammer snaprm <filesystem> <transid> ...
 */
void
hammer_cmd_snaprm(char **av, int ac)
{
        struct stat st;
        char linkbuf[1024];
        intmax_t tid;
        int fsfd = -1;
        int i;
        int delete;
        enum snaprm_mode { none_m, path_m, tid_m } mode = none_m;
        char *dirpath;
        char *ptr, *ptr2;

        if (ac == 0) {
                snapshot_usage(1);
                /* not reached */
        }

        for (i = 0; i < ac; ++i) {
                if (lstat(av[i], &st) < 0) {
                        tid = strtoull(av[i], &ptr, 16);
                        if (*ptr) {
                                err(2, "hammer snaprm: not a file or tid: %s",
                                    av[i]);
                                /* not reached */
                        }
                        if (mode == path_m) {
                                snapshot_usage(1);
                                /* not reached */
                        }
                        mode = tid_m;
                        if (fsfd < 0)
                                fsfd = open(".", O_RDONLY);
                        snapshot_del(fsfd, tid);
                } else if (S_ISDIR(st.st_mode)) {
                        if (i != 0 || ac < 2) {
                                snapshot_usage(1);
                                /* not reached */
                        }
                        if (fsfd >= 0)
                                close(fsfd);
                        fsfd = open(av[i], O_RDONLY);
                        if (fsfd < 0) {
                                err(2, "hammer snaprm: cannot open dir %s",
                                    av[i]);
                                /* not reached */
                        }
                        mode = tid_m;
                } else if (S_ISLNK(st.st_mode)) {
                        dirpath = dirpart(av[i]);
                        bzero(linkbuf, sizeof(linkbuf));
                        if (readlink(av[i], linkbuf, sizeof(linkbuf) - 1) < 0) {
                                err(2, "hammer snaprm: cannot read softlink: "
                                       "%s", av[i]);
                                /* not reached */
                        }
                        if (linkbuf[0] == '/') {
                                free(dirpath);
                                dirpath = dirpart(linkbuf);
                        } else {
                                asprintf(&ptr, "%s/%s", dirpath, linkbuf);
                                free(dirpath);
                                dirpath = dirpart(ptr);
                                free(ptr);
                        }

                        if (fsfd >= 0)
                                close(fsfd);
                        fsfd = open(dirpath, O_RDONLY);
                        if (fsfd < 0) {
                                err(2, "hammer snaprm: cannot open dir %s",
                                    dirpath);
                                /* not reached */
                        }

                        delete = 1;
                        if (i == 0 && ac > 1) {
                                mode = path_m;
                                if (lstat(av[1], &st) < 0) {
                                        tid = strtoull(av[1], &ptr, 16);
                                        if (*ptr == '\0') {
                                                delete = 0;
                                                mode = tid_m;
                                        }
                                }
                        } else {
                                if (mode == tid_m) {
                                        snapshot_usage(1);
                                        /* not reached */
                                }
                                mode = path_m;
                        }
                        if (delete && (ptr = strrchr(linkbuf, '@')) &&
                            ptr > linkbuf && ptr[-1] == '@' && ptr[1]) {
                                tid = strtoull(ptr + 1, &ptr2, 16);
                                if (*ptr2 == '\0') {
                                        snapshot_del(fsfd, tid);
                                        remove(av[i]);
                                }
                        }
                        free(dirpath);
                } else {
                        err(2, "hammer snaprm: not directory or snapshot "
                               "softlink: %s", av[i]);
                        /* not reached */
                }
        }
        if (fsfd >= 0)
                close(fsfd);
}

/*
 * snapshot <softlink-dir>
 * snapshot <filesystem> <softlink-dir> [<note>]
 */
void
hammer_cmd_snapshot(char **av, int ac)
{
        const char *filesystem;
        const char *softlink_dir;
        char *softlink_fmt;
        struct statfs buf;
        struct stat st;
        struct hammer_ioc_synctid synctid;
        char *from;
        char *to;
        char *note = NULL;

        if (ac == 1) {
                filesystem = NULL;
                softlink_dir = av[0];
        } else if (ac == 2) {
                filesystem = av[0];
                softlink_dir = av[1];
        } else if (ac == 3) {
                filesystem = av[0];
                softlink_dir = av[1];
                note = av[2];
        } else {
                snapshot_usage(1);
                /* not reached */
        }

        if (stat(softlink_dir, &st) == 0) {
                if (!S_ISDIR(st.st_mode)) {
                        err(2, "File %s already exists", softlink_dir);
                        /* not reached */
                }

                if (filesystem == NULL) {
                        if (statfs(softlink_dir, &buf) != 0) {
                                err(2, "Unable to determine filesystem of %s",
                                    softlink_dir);
                                /* not reached */
                        }
                        filesystem = buf.f_mntonname;
                }

                softlink_fmt = malloc(strlen(softlink_dir) + 1 + 1 +
                                      sizeof(DEFAULT_SNAPSHOT_NAME));
                if (softlink_fmt == NULL) {
                        err(2, "Failed to allocate string");
                        /* not reached */
                }

                strcpy(softlink_fmt, softlink_dir);
                if (softlink_fmt[strlen(softlink_fmt)-1] != '/')
                        strcat(softlink_fmt, "/");
                strcat(softlink_fmt, DEFAULT_SNAPSHOT_NAME);
        } else {
                softlink_fmt = strdup(softlink_dir);

                if (filesystem == NULL) {
                        /*
                         * strip-off last '/path' segment to get the softlink
                         * directory, which we need to determine the filesystem
                         * we are on.
                         */
                        char *pos = strrchr(softlink_fmt, '/');
                        if (pos != NULL)
                                *pos = '\0';

                        if (stat(softlink_fmt, &st) != 0 ||
                            !S_ISDIR(st.st_mode)) {
                                err(2, "Unable to determine softlink dir %s",
                                    softlink_fmt);
                                /* not reached */
                        }
                        if (statfs(softlink_fmt, &buf) != 0) {
                                err(2, "Unable to determine filesystem of %s",
                                    softlink_fmt);
                                /* not reached */
                        }
                        filesystem = buf.f_mntonname;

                        /* restore '/' */
                        if (pos != NULL)
                                *pos = '/';
                }
        }

        /*
         * Synctid
         */
        bzero(&synctid, sizeof(synctid));
        synctid.op = HAMMER_SYNCTID_SYNC2;

        int fd = open(filesystem, O_RDONLY);
        if (fd < 0) {
                err(2, "Unable to open %s", filesystem);
                /* not reached */
        }
        if (ioctl(fd, HAMMERIOC_SYNCTID, &synctid) < 0) {
                err(2, "Synctid %s failed", filesystem);
                /* not reached */
        }

        asprintf(&from, "%s/@@0x%016jx", filesystem, (uintmax_t)synctid.tid);
        if (from == NULL) {
                err(2, "Couldn't generate string");
                /* not reached */
        }

        int sz = strlen(softlink_fmt) + 50;
        to = malloc(sz);
        if (to == NULL) {
                err(2, "Failed to allocate string");
                /* not reached */
        }

        time_t t = time(NULL);
        if (strftime(to, sz, softlink_fmt, localtime(&t)) == 0) {
                err(2, "String buffer too small");
                /* not reached */
        }

        asprintf(&from, "%s/@@0x%016jx", filesystem, (uintmax_t)synctid.tid);

        snapshot_add(fd, from, to, note, synctid.tid);

        close(fd);
        printf("%s\n", to);

        free(softlink_fmt);
        free(from);
        free(to);
}

static
void
snapshot_add(int fd, const char *fsym, const char *tsym, const char *label,
             hammer_tid_t tid)
{
        struct hammer_ioc_version version;
        struct hammer_ioc_snapshot snapshot;

        bzero(&version, sizeof(version));
        bzero(&snapshot, sizeof(snapshot));

        /*
         * For HAMMER filesystem v3+ the snapshot is recorded in meta-data.
         */
        if (ioctl(fd, HAMMERIOC_GET_VERSION, &version) == 0 &&
            version.cur_version >= 3) {
                HammerVersion = version.cur_version;
                snapshot.index = 0;
                snapshot.count = 1;
                snapshot.snaps[0].tid = tid;
                snapshot.snaps[0].ts = time(NULL) * 1000000ULL;
                if (label) {
                        snprintf(snapshot.snaps[0].label,
                                 sizeof(snapshot.snaps[0].label),
                                 "%s",
                                 label);
                }
                if (ioctl(fd, HAMMERIOC_ADD_SNAPSHOT, &snapshot) < 0) {
                        err(2, "Unable to create snapshot");
                        /* not reached */
                } else if (snapshot.head.error &&
                           snapshot.head.error != EEXIST) {
                        errx(2, "Unable to create snapshot: %s",
                                strerror(snapshot.head.error));
                        /* not reached */
                }
        }

        /*
         * Create a symlink for the snapshot.  If a file exists with the same
         * name the new symlink will replace it.
         */
        if (fsym && tsym) {
                remove(tsym);
                if (symlink(fsym, tsym) < 0) {
                        err(2, "Unable to create symlink %s", tsym);
                        /* not reached */
                }
        }
}

static
void
snapshot_ls(const char *path)
{
        struct hammer_ioc_info info;
        struct hammer_ioc_snapshot snapshot;
        struct hammer_ioc_pseudofs_rw pfs;
        struct hammer_pseudofs_data pfs_od;
        hammer_snapshot_data_t snap;
        struct tm *tp;
        time_t t;
        uint32_t i;
        int fd;
        char snapts[64];

        fd = open(path, O_RDONLY);
        if (fd < 0) {
                err(2, "hammer snapls: cannot open %s", path);
                /* not reached */
        }

        clrpfs(&pfs, &pfs_od, -1);
        if (ioctl(fd, HAMMERIOC_GET_PSEUDOFS, &pfs) < 0) {
                err(2, "hammer snapls: cannot retrieve PFS info on %s", path);
                /* not reached */
        }

        bzero(&info, sizeof(info));
        if ((ioctl(fd, HAMMERIOC_GET_INFO, &info)) < 0) {
                err(2, "hammer snapls: cannot retrieve HAMMER info");
                /* not reached */
        }

        printf("Snapshots on %s\tPFS#%d\n", path, pfs.pfs_id);
        printf("Transaction ID\t\tTimestamp\t\tNote\n");

        bzero(&snapshot, sizeof(snapshot));
        do {
                if (ioctl(fd, HAMMERIOC_GET_SNAPSHOT, &snapshot) < 0) {
                        err(2, "hammer snapls: %s: not HAMMER fs or "
                                "version < 3", path);
                        /* not reached */
                }
                for (i = 0; i < snapshot.count; ++i) {
                        snap = &snapshot.snaps[i];

                        t = snap->ts / 1000000ULL;
                        tp = localtime(&t);
                        strftime(snapts, sizeof(snapts),
                                 "%Y-%m-%d %H:%M:%S %Z", tp);
                        printf("0x%016jx\t%s\t%s\n",
                                (uintmax_t)snap->tid, snapts,
                                strlen(snap->label) ? snap->label : "-");
                }
        } while (snapshot.head.error == 0 && snapshot.count);
}

static
void
snapshot_del(int fsfd, hammer_tid_t tid)
{
        struct hammer_ioc_snapshot snapshot;
        struct hammer_ioc_version version;

        bzero(&version, sizeof(version));

        if (ioctl(fsfd, HAMMERIOC_GET_VERSION, &version) < 0) {
                err(2, "hammer snaprm 0x%016jx", (uintmax_t)tid);
                /* not reached */
        }
        HammerVersion = version.cur_version;
        if (version.cur_version < 3) {
                errx(2, "hammer snaprm 0x%016jx: You must upgrade to version "
                        " 3 to use this directive", (uintmax_t)tid);
                /* not reached */
        }

        bzero(&snapshot, sizeof(snapshot));
        snapshot.count = 1;
        snapshot.snaps[0].tid = tid;

        /*
         * Do not abort if we are unable to remove the meta-data.
         */
        if (ioctl(fsfd, HAMMERIOC_DEL_SNAPSHOT, &snapshot) < 0) {
                err(2, "hammer snaprm 0x%016jx",
                      (uintmax_t)tid);
                /* not reached */
        } else if (snapshot.head.error == ENOENT) {
                fprintf(stderr, "Warning: hammer snaprm 0x%016jx: "
                                "meta-data not found\n",
                        (uintmax_t)tid);
        } else if (snapshot.head.error) {
                fprintf(stderr, "Warning: hammer snaprm 0x%016jx: %s\n",
                        (uintmax_t)tid, strerror(snapshot.head.error));
        }
}

static
void
snapshot_usage(int exit_code)
{
        fprintf(stderr,
    "hammer snap <path> [<note>]\t\tcreate snapshot & link, points to\n"
                                "\t\t\t\t\tbase of PFS mount\n"
    "hammer snaplo <path> [<note>]\t\tcreate snapshot & link, points to\n"
                                "\t\t\t\t\ttarget dir\n"
    "hammer snapq <dir> [<note>]\t\tcreate snapshot, output path to stdout\n"
    "hammer snaprm <path> ...\t\tdelete snapshots; filesystem is CWD\n"
    "hammer snaprm <transid> ...\t\tdelete snapshots\n"
    "hammer snaprm <filesystem> <transid> ...\tdelete snapshots\n"
    "hammer snapls [<path> ...]\t\tlist available snapshots\n"
    "\n"
    "NOTE: Snapshots are created in filesystem meta-data, any directory\n"
    "      in a HAMMER filesystem or PFS may be specified.  If the path\n"
    "      specified does not exist this function will also create a\n"
    "      softlink.\n"
    "\n"
    "      When deleting snapshots transaction ids may be directly specified\n"
    "      or file paths to snapshot softlinks may be specified.  If a\n"
    "      softlink is specified the softlink will also be deleted.\n"
    "\n"
    "NOTE: The old 'hammer snapshot [<filesystem>] <snapshot-dir>' form\n"
    "      is still accepted but is a deprecated form.  This form will\n"
    "      work for older hammer versions.  The new forms only work for\n"
    "      HAMMER version 3 or later filesystems.  HAMMER can be upgraded\n"
    "      to version 3 in-place.\n"
        );
        exit(exit_code);
}

static
char *
dirpart(const char *path)
{
        const char *ptr;
        char *res;

        ptr = strrchr(path, '/');
        if (ptr) {
                while (ptr > path && ptr[-1] == '/')
                        --ptr;
                if (ptr == path)
                        ptr = NULL;
        }
        if (ptr == NULL) {
                path = ".";
                ptr = path + 1;
        }
        res = malloc(ptr - path + 1);
        bcopy(path, res, ptr - path);
        res[ptr - path] = 0;
        return(res);
}