/*
 * Copyright (c) 2011 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Antonio Huete <tuxillo@quantumachine.net>
 *
 * 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.
 */

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <unistd.h>

#include "libhammer.h"

static u_int32_t count_snapshots(u_int32_t, char *, char *, int *);

libhammer_volinfo_t
libhammer_get_volinfo(const char *path)
{
	struct hammer_pseudofs_data *pfs_od;
	struct hammer_ioc_pfs_iterate pi;
	struct hammer_ioc_info info;
	libhammer_pfsinfo_t pfstmp;
	libhammer_volinfo_t hvi;
	int error = 0;
	int fd;

	if ((fd = open(path, O_RDONLY)) < 0)
		return NULL;

	hvi = _libhammer_malloc(sizeof(*hvi));
	TAILQ_INIT(&hvi->list_pseudo);
	if ((ioctl(fd, HAMMERIOC_GET_INFO, &info)) < 0) {
		libhammer_free_volinfo(hvi);
		close(fd);
		return NULL;
	}

	/* Fill volume information */
	snprintf(hvi->vol_name, TXTLEN, "%s", info.vol_name);
	hvi->vol_fsid = info.vol_fsid;
	hvi->version = info.version;
	hvi->nvolumes = info.nvolumes;
	hvi->inodes = info.inodes;
	hvi->bigblocks = info.bigblocks;
	hvi->freebigblocks = info.freebigblocks;
	hvi->rsvbigblocks = info.rsvbigblocks;

	bzero(&pi, sizeof(pi));
	pi.ondisk = _libhammer_malloc(sizeof(*pfs_od));
	while(error == 0) {
		error = ioctl(fd, HAMMERIOC_PFS_ITERATE, &pi);
		if (error == 0 &&
		    ((pi.head.flags & HAMMER_PFSD_DELETED) == 0)) {
			/*
			 * XXX - In the case the path passed is on PFS#0 but it
			 * is not the mountpoint itself, it could produce a
			 * wrong type of PFS.
			 */
			pfstmp = _libhammer_malloc(sizeof(*pfstmp));
			pfs_od = pi.ondisk;
			pfstmp->ismaster =
			    (pfs_od->mirror_flags & HAMMER_PFSD_SLAVE) ? 0 : 1;

			if (pi.pos == 0)
				pfstmp->mountedon = strdup(path);
			else
				pfstmp->mountedon =
				    libhammer_find_pfs_mount(pi.pos,
					hvi->vol_fsid, pfstmp->ismaster);
			/*
			 * Fill in structs used in the library. We don't rely on
			 * HAMMER own struct but we do fill our own.
			 */
			pfstmp->version = hvi->version;
			pfstmp->pfs_id = pi.pos;
			pfstmp->mirror_flags = pfs_od->mirror_flags;
			pfstmp->beg_tid = pfs_od->sync_beg_tid;
			pfstmp->end_tid = pfs_od->sync_end_tid;
			pfstmp->snapcount = count_snapshots(hvi->version,
			    pfstmp->snapshots, pfstmp->mountedon,
			    &pfstmp->head.error);

			TAILQ_INSERT_TAIL(&hvi->list_pseudo, pfstmp, entries);
		}
		pi.pos++;
	}
	free(pi.ondisk);

	close (fd);

	return (hvi);
}

void
libhammer_free_volinfo(libhammer_volinfo_t volinfo)
{
	struct libhammer_pfsinfo *pfstmp;

	while(!TAILQ_EMPTY(&volinfo->list_pseudo)) {
		pfstmp = TAILQ_FIRST(&volinfo->list_pseudo);
		free(pfstmp->mountedon);
		TAILQ_REMOVE(&volinfo->list_pseudo, pfstmp, entries);
		free(pfstmp);
	}
	free(volinfo);
}

static u_int32_t
count_snapshots(u_int32_t version, char *pfs_snapshots, char *mountedon,
    int *errorp)
{
	struct hammer_ioc_snapshot snapinfo;
	char *snapshots_path, *fpath;
	struct dirent *den;
	struct stat st;
	DIR *dir;
	u_int32_t snapshot_count;
	int fd;
	int spallocated;

	snapshot_count = 0;

	bzero(&snapinfo, sizeof(struct hammer_ioc_snapshot));

	fd = open(mountedon, O_RDONLY);
	if (fd < 0) {
		*errorp = errno;
		return 0;
	}

	if (version < 3) {
		/*
		 * old style: count the number of softlinks in the snapshots dir
		 */
		if (pfs_snapshots[0]) {
			snapshots_path = pfs_snapshots;
			spallocated = 0;
		} else {
			asprintf(&snapshots_path, "%s/snapshots", mountedon);
			spallocated = 1;
		}
		if ((dir = opendir(snapshots_path)) != NULL) {
			while ((den = readdir(dir)) != NULL) {
				if (den->d_name[0] == '.')
					continue;
				asprintf(&fpath, "%s/%s", snapshots_path,
				    den->d_name);
				if (lstat(fpath, &st) == 0 &&
				    S_ISLNK(st.st_mode))
					snapshot_count++;
				free(fpath);
			}
			closedir(dir);
		}
		if (spallocated)
			free(snapshots_path);
	} else {
		/*
		 * new style: file system meta-data
		 */
		do {
			if (ioctl(fd, HAMMERIOC_GET_SNAPSHOT, &snapinfo) < 0) {
				*errorp = errno;
				goto out;
			}

			snapshot_count += snapinfo.count;
		} while (snapinfo.head.error == 0 && snapinfo.count);
	}

out:
	if (fd != -1)
		close(fd);
	return snapshot_count;
}