/*
 *  diskspace.c
 *
 *  Copyright (c) 2010 Pacman Development Team <pacman-dev@archlinux.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "config.h"

#if defined HAVE_GETMNTENT
#include <mntent.h>
#include <sys/statvfs.h>
#elif defined HAVE_GETMNTINFO_STATFS
#include <sys/param.h>
#include <sys/mount.h>
#if HAVE_SYS_UCRED_H
#include <sys/ucred.h>
#endif
#elif defined HAVE_GETMNTINFO_STATVFS
#include <sys/types.h>
#include <sys/statvfs.h>
#endif

#include <math.h>

/* libarchive */
#include <archive.h>
#include <archive_entry.h>

/* libalpm */
#include "diskspace.h"
#include "alpm_list.h"
#include "util.h"
#include "log.h"
#include "handle.h"

static int mount_point_cmp(const alpm_mountpoint_t *mp1, const alpm_mountpoint_t *mp2)
{
	return(strcmp(mp1->mount_dir, mp2->mount_dir));
}

static alpm_list_t *mount_point_list()
{
	alpm_list_t *mount_points = NULL;
	alpm_mountpoint_t *mp;

#if defined HAVE_GETMNTENT
	struct mntent *mnt;
	FILE *fp;
	struct statvfs fsp;

	fp = setmntent(MOUNTED, "r");

	if (fp == NULL) {
		return NULL;
	}

	while((mnt = getmntent (fp))) {
		if(statvfs(mnt->mnt_dir, &fsp) != 0) {
			_alpm_log(PM_LOG_WARNING, "could not get filesystem information for %s\n", mnt->mnt_dir);
			continue;
		}

		MALLOC(mp, sizeof(alpm_mountpoint_t), RET_ERR(PM_ERR_MEMORY, NULL));
		mp->mount_dir = strdup(mnt->mnt_dir);

		MALLOC(mp->fsp, sizeof(struct statvfs), RET_ERR(PM_ERR_MEMORY, NULL));
		memcpy((void *)(mp->fsp), (void *)(&fsp), sizeof(struct statvfs));

		mp->blocks_needed = 0;
		mp->max_blocks_needed = 0;
		mp->used = 0;

		mount_points = alpm_list_add(mount_points, mp);
	}

	endmntent(fp);
#elif defined HAVE_GETMNTINFO_STATFS
	int entries;
	struct statfs *fsp;

	entries = getmntinfo(&fsp, MNT_NOWAIT);

	if (entries < 0) {
		return NULL;
	}

	for(; entries-- > 0; fsp++) {
		MALLOC(mp, sizeof(alpm_mountpoint_t), RET_ERR(PM_ERR_MEMORY, NULL));
		mp->mount_dir = strdup(fsp->f_mntonname);

		MALLOC(mp->fsp, sizeof(struct statfs), RET_ERR(PM_ERR_MEMORY, NULL));
		memcpy((void *)(mp->fsp), (void *)fsp, sizeof(struct statfs));

		mp->blocks_needed = 0;
		mp->max_blocks_needed = 0;

		mount_points = alpm_list_add(mount_points, mp);
	}
#elif defined HAVE_GETMNTINFO_STATVFS
	int entries;
	struct statvfs *fsp;

	entries = getmntinfo(&fsp, MNT_NOWAIT);

	if (entries < 0) {
		return NULL;
	}

	for (; entries-- > 0; fsp++) {
		MALLOC(mp, sizeof(alpm_mountpoint_t), RET_ERR(PM_ERR_MEMORY, NULL));
		mp->mount_dir = strdup(fsp->f_mntonname);

		MALLOC(mp->fsp, sizeof(struct statvfs), RET_ERR(PM_ERR_MEMORY, NULL));
		memcpy((void *)(mp->fsp), (void *)fsp, sizeof(struct statvfs));

		mp->blocks_needed = 0;
		mp->max_blocks_needed = 0;

		mount_points = alpm_list_add(mount_points, mp);
	}
#endif

	mount_points = alpm_list_msort(mount_points, alpm_list_count(mount_points),
	                                   (alpm_list_fn_cmp)mount_point_cmp);
	return(mount_points);
}

static alpm_list_t *match_mount_point(const alpm_list_t *mount_points, const char *file)
{
	char real_path[PATH_MAX];
	snprintf(real_path, PATH_MAX, "%s%s", handle->root, file);

	alpm_list_t *mp = alpm_list_last(mount_points);
	do {
		alpm_mountpoint_t *data = mp->data;

		if(strncmp(data->mount_dir, real_path, strlen(data->mount_dir)) == 0) {
			return mp;
		}

		mp = mp->prev;
	} while (mp != alpm_list_last(mount_points));

	/* should not get here... */
	return NULL;
}

static int calculate_removed_size(pmpkg_t *pkg, const alpm_list_t *mount_points)
{
	alpm_list_t *file;

	alpm_list_t *files = alpm_pkg_get_files(pkg);
	for(file = files; file; file = file->next) {
		alpm_list_t *mp;
		alpm_mountpoint_t *data;
		struct stat st;
		char path[PATH_MAX];

		/* skip directories to be consistent with libarchive that reports them to be zero size
		   and to prevent multiple counting across packages */
		if(*((char *)(file->data) + strlen(file->data) - 1) == '/') {
			continue;
		}

		mp = match_mount_point(mount_points, file->data);
		if(mp == NULL) {
			_alpm_log(PM_LOG_WARNING, _("could not determine mount point for file %s"), (char *)(file->data));
			continue;
		}

		snprintf(path, PATH_MAX, "%s%s", handle->root, (char *)file->data);
		_alpm_lstat(path, &st);

		/* skip symlinks to be consistent with libarchive that reports them to be zero size */
		if(S_ISLNK(st.st_mode)) {
			continue;
		}

		data = mp->data;
		data->blocks_needed -= ceil((double)(st.st_size) /
		                            (double)(data->fsp->f_bsize));
		data->used = 1;
	}

	return 0;
}

static int calculate_installed_size(pmpkg_t *pkg, const alpm_list_t *mount_points)
{
	int ret=0;
	struct archive *archive;
	struct archive_entry *entry;
	const char *file;

	if ((archive = archive_read_new()) == NULL) {
		pm_errno = PM_ERR_LIBARCHIVE;
		ret = -1;
		goto cleanup;
	}

	archive_read_support_compression_all(archive);
	archive_read_support_format_all(archive);

	if(archive_read_open_filename(archive, pkg->origin_data.file,
				ARCHIVE_DEFAULT_BYTES_PER_BLOCK) != ARCHIVE_OK) {
		pm_errno = PM_ERR_PKG_OPEN;
		ret = -1;
		goto cleanup;
	}

	while(archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
		alpm_list_t *mp;
		alpm_mountpoint_t *data;

		file = archive_entry_pathname(entry);

		/* approximate space requirements for db entries */
		if(strcmp(file, ".PKGINFO") == 0 ||
		   strcmp(file, ".INSTALL") == 0 ||
		   strcmp(file, ".CHANGELOG") == 0) {
			file = alpm_option_get_dbpath();
		}

		mp = match_mount_point(mount_points, file);
		if(mp == NULL) {
			_alpm_log(PM_LOG_WARNING, _("could not determine mount point for file %s"), archive_entry_pathname(entry));
			continue;
		}

		data = mp->data;
		data->blocks_needed += ceil((double)(archive_entry_size(entry)) /
		                            (double)(data->fsp->f_bsize));
		data->used = 1;
	}

	archive_read_finish(archive);

cleanup:
	return ret;
}

int _alpm_check_diskspace(pmtrans_t *trans, pmdb_t *db)
{
	alpm_list_t *mount_points, *i;
	int replaces = 0, abort = 0;
	alpm_list_t *targ;
	pmpkg_t *pkg;

	mount_points = mount_point_list();
	if(mount_points == NULL) {
		_alpm_log(PM_LOG_ERROR, _("count not determine filesystem mount points"));
		return -1;
	}

	replaces = alpm_list_count(trans->remove);
	if(replaces) {
		for(targ = trans->remove; targ; targ = targ->next) {
			pkg = (pmpkg_t*)targ->data;
			calculate_removed_size(pkg, mount_points);
		}
	}

	for(targ = trans->add; targ; targ = targ->next) {
		pkg = (pmpkg_t*)targ->data;
		if(_alpm_db_get_pkgfromcache(db, pkg->name)) {
			calculate_removed_size(pkg, mount_points);
		}
		calculate_installed_size(pkg, mount_points);

		for(i = mount_points; i; i = alpm_list_next(i)) {
			alpm_mountpoint_t *data = i->data;
			if(data->blocks_needed > data->max_blocks_needed) {
				data->max_blocks_needed = data->blocks_needed;
			}
		}
	}

	for(i = mount_points; i; i = alpm_list_next(i)) {
		alpm_mountpoint_t *data = i->data;
		if(data->used == 1) {
			_alpm_log(PM_LOG_DEBUG, "partition %s, needed %ld, free %ld\n",
			          data->mount_dir, data->max_blocks_needed, (long int)(data->fsp->f_bfree));
			if(data->max_blocks_needed > data->fsp->f_bfree) {
				abort = 1;
			}
		}
	}

	for(i = mount_points; i; i = alpm_list_next(i)) {
		alpm_mountpoint_t *data = i->data;
		FREE(data->mount_dir);
		FREE(data->fsp);
	}
	FREELIST(mount_points);

	if(abort) {
		RET_ERR(PM_ERR_DISK_SPACE, -1);
	}

	return 0;
}

/* vim: set ts=2 sw=2 noet: */