Пример #1
0
/** Open an archive for reading and perform the necessary boilerplate.
 * This takes care of creating the libarchive 'archive' struct, setting up
 * compression and format options, opening a file descriptor, setting up the
 * buffer size, and performing a stat on the path once opened.
 * On error, no file descriptor is opened, and the archive pointer returned
 * will be set to NULL.
 * @param handle the context handle
 * @param path the path of the archive to open
 * @param buf space for a stat buffer for the given path
 * @param archive pointer to place the created archive object
 * @param error error code to set on failure to open archive
 * @return -1 on failure, >=0 file descriptor on success
 */
int _alpm_open_archive(alpm_handle_t *handle, const char *path,
		struct stat *buf, struct archive **archive, alpm_errno_t error)
{
	int fd;
	size_t bufsize = ALPM_BUFFER_SIZE;
	errno = 0;

	if((*archive = archive_read_new()) == NULL) {
		RET_ERR(handle, ALPM_ERR_LIBARCHIVE, -1);
	}

	_alpm_archive_read_support_filter_all(*archive);
	archive_read_support_format_all(*archive);

	_alpm_log(handle, ALPM_LOG_DEBUG, "opening archive %s\n", path);
	OPEN(fd, path, O_RDONLY | O_CLOEXEC);
	if(fd < 0) {
		_alpm_log(handle, ALPM_LOG_ERROR,
				_("could not open file %s: %s\n"), path, strerror(errno));
		goto error;
	}

	if(fstat(fd, buf) != 0) {
		_alpm_log(handle, ALPM_LOG_ERROR,
				_("could not stat file %s: %s\n"), path, strerror(errno));
		goto error;
	}
#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
	if(buf->st_blksize > ALPM_BUFFER_SIZE) {
		bufsize = buf->st_blksize;
	}
#endif

	if(archive_read_open_fd(*archive, fd, bufsize) != ARCHIVE_OK) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("could not open file %s: %s\n"),
				path, archive_error_string(*archive));
		goto error;
	}

	return fd;

error:
	_alpm_archive_read_free(*archive);
	*archive = NULL;
	if(fd >= 0) {
		close(fd);
	}
	RET_ERR(handle, error, -1);
}
Пример #2
0
/**
 * Open a package mtree file for reading.
 * @param pkg the local package to read the changelog of
 * @return a archive structure for the package mtree file
 */
static struct archive *_cache_mtree_open(alpm_pkg_t *pkg)
{
	int r;
	struct archive *mtree;

	alpm_db_t *db = alpm_pkg_get_db(pkg);
	char *mtfile = _alpm_local_db_pkgpath(db, pkg, "mtree");

	if(access(mtfile, F_OK) != 0) {
		/* there is no mtree file for this package */
		goto error;
	}

	if((mtree = archive_read_new()) == NULL) {
		pkg->handle->pm_errno = ALPM_ERR_LIBARCHIVE;
		goto error;
	}

	_alpm_archive_read_support_filter_all(mtree);
	archive_read_support_format_mtree(mtree);

	if((r = _alpm_archive_read_open_file(mtree, mtfile, ALPM_BUFFER_SIZE))) {
		_alpm_log(pkg->handle, ALPM_LOG_ERROR, _("error while reading file %s: %s\n"),
					mtfile, archive_error_string(mtree));
		pkg->handle->pm_errno = ALPM_ERR_LIBARCHIVE;
		_alpm_archive_read_free(mtree);
		goto error;
	}

	free(mtfile);
	return mtree;

error:
	free(mtfile);
	return NULL;
}
Пример #3
0
static int extract_single_file(alpm_handle_t *handle, struct archive *archive,
		struct archive_entry *entry, alpm_pkg_t *newpkg, alpm_pkg_t *oldpkg)
{
	const char *entryname = archive_entry_pathname(entry);
	mode_t entrymode = archive_entry_mode(entry);
	alpm_backup_t *backup = _alpm_needbackup(entryname, newpkg);
	char filename[PATH_MAX]; /* the actual file we're extracting */
	int needbackup = 0, notouch = 0;
	const char *hash_orig = NULL;
	int isnewfile = 0, errors = 0;
	struct stat lsbuf;
	size_t filename_len;

	if(*entryname == '.') {
		return extract_db_file(handle, archive, entry, newpkg, entryname);
	}

	if (!alpm_filelist_contains(&newpkg->files, entryname)) {
		_alpm_log(handle, ALPM_LOG_WARNING,
				_("file not found in file list for package %s. skipping extraction of %s\n"),
				newpkg->name, entryname);
		return 0;
	}

	/* build the new entryname relative to handle->root */
	filename_len = snprintf(filename, PATH_MAX, "%s%s", handle->root, entryname);
	if(filename_len >= PATH_MAX) {
		_alpm_log(handle, ALPM_LOG_ERROR,
				_("unable to extract %s%s: path too long"), handle->root, entryname);
		return 1;
	}

	/* if a file is in NoExtract then we never extract it */
	if(_alpm_fnmatch_patterns(handle->noextract, entryname) == 0) {
		_alpm_log(handle, ALPM_LOG_DEBUG, "%s is in NoExtract,"
				" skipping extraction of %s\n",
				entryname, filename);
		archive_read_data_skip(archive);
		return 0;
	}

	/* Check for file existence. This is one of the more crucial parts
	 * to get 'right'. Here are the possibilities, with the filesystem
	 * on the left and the package on the top:
	 * (F=file, N=node, S=symlink, D=dir)
	 *               |  F/N  |   D
	 *  non-existent |   1   |   2
	 *  F/N          |   3   |   4
	 *  D            |   5   |   6
	 *
	 *  1,2- extract, no magic necessary. lstat (llstat) will fail here.
	 *  3,4- conflict checks should have caught this. either overwrite
	 *      or backup the file.
	 *  5- file replacing directory- don't allow it.
	 *  6- skip extraction, dir already exists.
	 */

	isnewfile = llstat(filename, &lsbuf) != 0;
	if(isnewfile) {
		/* cases 1,2: file doesn't exist, skip all backup checks */
	} else if(S_ISDIR(lsbuf.st_mode) && S_ISDIR(entrymode)) {
#if 0
		uid_t entryuid = archive_entry_uid(entry);
		gid_t entrygid = archive_entry_gid(entry);
#endif

		/* case 6: existing dir, ignore it */
		if(lsbuf.st_mode != entrymode) {
			/* if filesystem perms are different than pkg perms, warn user */
			mode_t mask = 07777;
			_alpm_log(handle, ALPM_LOG_WARNING, _("directory permissions differ on %s\n"
					"filesystem: %o  package: %o\n"), filename, lsbuf.st_mode & mask,
					entrymode & mask);
			alpm_logaction(handle, ALPM_CALLER_PREFIX,
					"warning: directory permissions differ on %s\n"
					"filesystem: %o  package: %o\n", filename, lsbuf.st_mode & mask,
					entrymode & mask);
		}
#ifndef __MSYS__

#if 0
		/* Disable this warning until our user management in packages has improved.
		   Currently many packages have to create users in post_install and chown the
		   directories. These all resulted in "false-positive" warnings. */

		if((entryuid != lsbuf.st_uid) || (entrygid != lsbuf.st_gid)) {
			_alpm_log(handle, ALPM_LOG_WARNING, _("directory ownership differs on %s\n"
					"filesystem: %u:%u  package: %u:%u\n"), filename,
					lsbuf.st_uid, lsbuf.st_gid, entryuid, entrygid);
			alpm_logaction(handle, ALPM_CALLER_PREFIX,
					"warning: directory ownership differs on %s\n"
					"filesystem: %u:%u  package: %u:%u\n", filename,
					lsbuf.st_uid, lsbuf.st_gid, entryuid, entrygid);
		}
#endif

#endif
		_alpm_log(handle, ALPM_LOG_DEBUG, "extract: skipping dir extraction of %s\n",
				filename);
		archive_read_data_skip(archive);
		return 0;
	} else if(S_ISDIR(lsbuf.st_mode)) {
		/* case 5: trying to overwrite dir with file, don't allow it */
		_alpm_log(handle, ALPM_LOG_ERROR, _("extract: not overwriting dir with file %s\n"),
				filename);
		archive_read_data_skip(archive);
		return 1;
	} else if(S_ISDIR(entrymode)) {
		/* case 4: trying to overwrite file with dir */
		_alpm_log(handle, ALPM_LOG_DEBUG, "extract: overwriting file with dir %s\n",
				filename);
	} else {
		/* case 3: trying to overwrite file with file */
		/* if file is in NoUpgrade, don't touch it */
		if(_alpm_fnmatch_patterns(handle->noupgrade, entryname) == 0) {
			notouch = 1;
		} else {
			alpm_backup_t *oldbackup;
			if(oldpkg && (oldbackup = _alpm_needbackup(entryname, oldpkg))) {
				hash_orig = oldbackup->hash;
				needbackup = 1;
			} else if(backup) {
				/* allow adding backup files retroactively */
				needbackup = 1;
			}
		}
	}

	if(notouch || needbackup) {
		if(filename_len + strlen(".pacnew") >= PATH_MAX) {
			_alpm_log(handle, ALPM_LOG_ERROR,
					_("unable to extract %s.pacnew: path too long"), filename);
			return 1;
		}
		strcpy(filename + filename_len, ".pacnew");
		isnewfile = (llstat(filename, &lsbuf) != 0 && errno == ENOENT);
	}

	_alpm_log(handle, ALPM_LOG_DEBUG, "extracting %s\n", filename);
	if(perform_extraction(handle, archive, entry, filename)) {
		errors++;
		return errors;
	}

	if(backup) {
		FREE(backup->hash);
		backup->hash = alpm_compute_md5sum(filename);
	}

	if(notouch) {
		alpm_event_pacnew_created_t event = {
			.type = ALPM_EVENT_PACNEW_CREATED,
			.from_noupgrade = 1,
			.oldpkg = oldpkg,
			.newpkg = newpkg,
			.file = filename
		};
		/* "remove" the .pacnew suffix */
		filename[filename_len] = '\0';
		EVENT(handle, &event);
		alpm_logaction(handle, ALPM_CALLER_PREFIX,
				"warning: %s installed as %s.pacnew\n", filename, filename);
	} else if(needbackup) {
		char *hash_local = NULL, *hash_pkg = NULL;
		char origfile[PATH_MAX] = "";

		strncat(origfile, filename, filename_len);

		hash_local = alpm_compute_md5sum(origfile);
		hash_pkg = backup ? backup->hash : alpm_compute_md5sum(filename);

		_alpm_log(handle, ALPM_LOG_DEBUG, "checking hashes for %s\n", origfile);
		_alpm_log(handle, ALPM_LOG_DEBUG, "current:  %s\n", hash_local);
		_alpm_log(handle, ALPM_LOG_DEBUG, "new:      %s\n", hash_pkg);
		_alpm_log(handle, ALPM_LOG_DEBUG, "original: %s\n", hash_orig);

		if(hash_local && hash_pkg && strcmp(hash_local, hash_pkg) == 0) {
			/* local and new files are the same, updating anyway to get
			 * correct timestamps */
			_alpm_log(handle, ALPM_LOG_DEBUG, "action: installing new file: %s\n",
					origfile);
			if(try_rename(handle, filename, origfile)) {
				errors++;
			}
		} else if(hash_orig && hash_pkg && strcmp(hash_orig, hash_pkg) == 0) {
			/* original and new files are the same, leave the local version alone,
			 * including any user changes */
			_alpm_log(handle, ALPM_LOG_DEBUG,
					"action: leaving existing file in place\n");
			if(isnewfile) {
				unlink(filename);
			}
		} else if(hash_orig && hash_local && strcmp(hash_orig, hash_local) == 0) {
			/* installed file has NOT been changed by user,
			 * update to the new version */
			_alpm_log(handle, ALPM_LOG_DEBUG, "action: installing new file: %s\n",
					origfile);
			if(try_rename(handle, filename, origfile)) {
				errors++;
			}
		} else {
			/* none of the three files matched another,  leave the unpacked
			 * file alongside the local file */
			alpm_event_pacnew_created_t event = {
				.type = ALPM_EVENT_PACNEW_CREATED,
				.from_noupgrade = 0,
				.oldpkg = oldpkg,
				.newpkg = newpkg,
				.file = origfile
			};
			_alpm_log(handle, ALPM_LOG_DEBUG,
					"action: keeping current file and installing"
					" new one with .pacnew ending\n");
			EVENT(handle, &event);
			alpm_logaction(handle, ALPM_CALLER_PREFIX,
					"warning: %s installed as %s\n", origfile, filename);
		}

		free(hash_local);
		if(!backup) {
			free(hash_pkg);
		}
	}
	return errors;
}

static int commit_single_pkg(alpm_handle_t *handle, alpm_pkg_t *newpkg,
		size_t pkg_current, size_t pkg_count)
{
	int i, ret = 0, errors = 0;
	int is_upgrade = 0;
	alpm_pkg_t *oldpkg = NULL;
	alpm_db_t *db = handle->db_local;
	alpm_trans_t *trans = handle->trans;
	alpm_progress_t progress = ALPM_PROGRESS_ADD_START;
	alpm_event_package_operation_t event;
	const char *log_msg = "adding";
	const char *pkgfile;

	ASSERT(trans != NULL, return -1);

	/* see if this is an upgrade. if so, remove the old package first */
	if((oldpkg = newpkg->oldpkg)) {
		int cmp = _alpm_pkg_compare_versions(newpkg, oldpkg);
		if(cmp < 0) {
			log_msg = "downgrading";
			progress = ALPM_PROGRESS_DOWNGRADE_START;
			event.operation = ALPM_PACKAGE_DOWNGRADE;
		} else if(cmp == 0) {
			log_msg = "reinstalling";
			progress = ALPM_PROGRESS_REINSTALL_START;
			event.operation = ALPM_PACKAGE_REINSTALL;
		} else {
			log_msg = "upgrading";
			progress = ALPM_PROGRESS_UPGRADE_START;
			event.operation = ALPM_PACKAGE_UPGRADE;
		}
		is_upgrade = 1;

		/* copy over the install reason */
		newpkg->reason = alpm_pkg_get_reason(oldpkg);
	} else {
		event.operation = ALPM_PACKAGE_INSTALL;
	}

	event.type = ALPM_EVENT_PACKAGE_OPERATION_START;
	event.oldpkg = oldpkg;
	event.newpkg = newpkg;
	EVENT(handle, &event);

	pkgfile = newpkg->origin_data.file;

	_alpm_log(handle, ALPM_LOG_DEBUG, "%s package %s-%s\n",
			log_msg, newpkg->name, newpkg->version);
		/* pre_install/pre_upgrade scriptlet */
	if(alpm_pkg_has_scriptlet(newpkg) &&
			!(trans->flags & ALPM_TRANS_FLAG_NOSCRIPTLET)) {
		const char *scriptlet_name = is_upgrade ? "pre_upgrade" : "pre_install";

		_alpm_runscriptlet(handle, pkgfile, scriptlet_name,
				newpkg->version, oldpkg ? oldpkg->version : NULL, 1);
	}

	/* we override any pre-set reason if we have alldeps or allexplicit set */
	if(trans->flags & ALPM_TRANS_FLAG_ALLDEPS) {
		newpkg->reason = ALPM_PKG_REASON_DEPEND;
	} else if(trans->flags & ALPM_TRANS_FLAG_ALLEXPLICIT) {
		newpkg->reason = ALPM_PKG_REASON_EXPLICIT;
	}

	if(oldpkg) {
		/* set up fake remove transaction */
		if(_alpm_remove_single_package(handle, oldpkg, newpkg, 0, 0) == -1) {
			handle->pm_errno = ALPM_ERR_TRANS_ABORT;
			ret = -1;
			goto cleanup;
		}
	}

	/* prepare directory for database entries so permission are correct after
	   changelog/install script installation */
	if(_alpm_local_db_prepare(db, newpkg)) {
		alpm_logaction(handle, ALPM_CALLER_PREFIX,
				"error: could not create database entry %s-%s\n",
				newpkg->name, newpkg->version);
		handle->pm_errno = ALPM_ERR_DB_WRITE;
		ret = -1;
		goto cleanup;
	}

	if(!(trans->flags & ALPM_TRANS_FLAG_DBONLY)) {
		struct archive *archive;
		struct archive_entry *entry;
		struct stat buf;
		int fd, cwdfd;

		_alpm_log(handle, ALPM_LOG_DEBUG, "extracting files\n");

		fd = _alpm_open_archive(db->handle, pkgfile, &buf,
				&archive, ALPM_ERR_PKG_OPEN);
		if(fd < 0) {
			ret = -1;
			goto cleanup;
		}

		/* save the cwd so we can restore it later */
		OPEN(cwdfd, ".", O_RDONLY | O_CLOEXEC);
		if(cwdfd < 0) {
			_alpm_log(handle, ALPM_LOG_ERROR, _("could not get current working directory\n"));
		}

		/* libarchive requires this for extracting hard links */
		if(chdir(handle->root) != 0) {
			_alpm_log(handle, ALPM_LOG_ERROR, _("could not change directory to %s (%s)\n"),
					handle->root, strerror(errno));
			_alpm_archive_read_free(archive);
			close(fd);
			ret = -1;
			goto cleanup;
		}

		/* call PROGRESS once with 0 percent, as we sort-of skip that here */
		PROGRESS(handle, progress, newpkg->name, 0, pkg_count, pkg_current);

		for(i = 0; archive_read_next_header(archive, &entry) == ARCHIVE_OK; i++) {
			int percent;

			if(newpkg->size != 0) {
				/* Using compressed size for calculations here, as newpkg->isize is not
				 * exact when it comes to comparing to the ACTUAL uncompressed size
				 * (missing metadata sizes) */
				int64_t pos = _alpm_archive_compressed_ftell(archive);
				percent = (pos * 100) / newpkg->size;
				if(percent >= 100) {
					percent = 100;
				}
			} else {
				percent = 0;
			}

			PROGRESS(handle, progress, newpkg->name, percent, pkg_count, pkg_current);

			/* extract the next file from the archive */
			errors += extract_single_file(handle, archive, entry, newpkg, oldpkg);
		}
		_alpm_archive_read_free(archive);
		close(fd);

		/* restore the old cwd if we have it */
		if(cwdfd >= 0) {
			if(fchdir(cwdfd) != 0) {
				_alpm_log(handle, ALPM_LOG_ERROR,
						_("could not restore working directory (%s)\n"), strerror(errno));
			}
			close(cwdfd);
		}

		if(errors) {
			ret = -1;
			if(is_upgrade) {
				_alpm_log(handle, ALPM_LOG_ERROR, _("problem occurred while upgrading %s\n"),
						newpkg->name);
				alpm_logaction(handle, ALPM_CALLER_PREFIX,
						"error: problem occurred while upgrading %s\n",
						newpkg->name);
			} else {
				_alpm_log(handle, ALPM_LOG_ERROR, _("problem occurred while installing %s\n"),
						newpkg->name);
				alpm_logaction(handle, ALPM_CALLER_PREFIX,
						"error: problem occurred while installing %s\n",
						newpkg->name);
			}
		}
	}

	/* make an install date (in UTC) */
	newpkg->installdate = time(NULL);

	_alpm_log(handle, ALPM_LOG_DEBUG, "updating database\n");
	_alpm_log(handle, ALPM_LOG_DEBUG, "adding database entry '%s'\n", newpkg->name);

	if(_alpm_local_db_write(db, newpkg, INFRQ_ALL)) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("could not update database entry %s-%s\n"),
				newpkg->name, newpkg->version);
		alpm_logaction(handle, ALPM_CALLER_PREFIX,
				"error: could not update database entry %s-%s\n",
				newpkg->name, newpkg->version);
		handle->pm_errno = ALPM_ERR_DB_WRITE;
		ret = -1;
		goto cleanup;
	}

	if(_alpm_db_add_pkgincache(db, newpkg) == -1) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("could not add entry '%s' in cache\n"),
				newpkg->name);
	}

	PROGRESS(handle, progress, newpkg->name, 100, pkg_count, pkg_current);

	switch(event.operation) {
		case ALPM_PACKAGE_INSTALL:
			alpm_logaction(handle, ALPM_CALLER_PREFIX, "installed %s (%s)\n",
					newpkg->name, newpkg->version);
			break;
		case ALPM_PACKAGE_DOWNGRADE:
			alpm_logaction(handle, ALPM_CALLER_PREFIX, "downgraded %s (%s -> %s)\n",
					newpkg->name, oldpkg->version, newpkg->version);
			break;
		case ALPM_PACKAGE_REINSTALL:
			alpm_logaction(handle, ALPM_CALLER_PREFIX, "reinstalled %s (%s)\n",
					newpkg->name, newpkg->version);
			break;
		case ALPM_PACKAGE_UPGRADE:
			alpm_logaction(handle, ALPM_CALLER_PREFIX, "upgraded %s (%s -> %s)\n",
					newpkg->name, oldpkg->version, newpkg->version);
			break;
		default:
			/* we should never reach here */
			break;
	}

	/* run the post-install script if it exists */
	if(alpm_pkg_has_scriptlet(newpkg)
			&& !(trans->flags & ALPM_TRANS_FLAG_NOSCRIPTLET)) {
		char *scriptlet = _alpm_local_db_pkgpath(db, newpkg, "install");
		const char *scriptlet_name = is_upgrade ? "post_upgrade" : "post_install";

		_alpm_runscriptlet(handle, scriptlet, scriptlet_name,
				newpkg->version, oldpkg ? oldpkg->version : NULL, 0);
		free(scriptlet);
	}

	event.type = ALPM_EVENT_PACKAGE_OPERATION_DONE;
	EVENT(handle, &event);

cleanup:
	return ret;
}
Пример #4
0
/**
 * Close a package mtree file for reading.
 * @param pkg the package that the mtree file was read from
 * @param mtree the archive structure use for reading from the mtree file
 * @return whether closing the package changelog stream was successful
 */
static int _cache_mtree_close(const alpm_pkg_t UNUSED *pkg,
		struct archive *mtree)
{
	return _alpm_archive_read_free(mtree);
}
Пример #5
0
static int sync_db_populate(alpm_db_t *db)
{
	const char *dbpath;
	size_t est_count;
	int count, fd;
	struct stat buf;
	struct archive *archive;
	struct archive_entry *entry;
	alpm_pkg_t *pkg = NULL;

	if(db->status & DB_STATUS_INVALID) {
		RET_ERR(db->handle, ALPM_ERR_DB_INVALID, -1);
	}
	if(db->status & DB_STATUS_MISSING) {
		RET_ERR(db->handle, ALPM_ERR_DB_NOT_FOUND, -1);
	}
	dbpath = _alpm_db_path(db);
	if(!dbpath) {
		/* pm_errno set in _alpm_db_path() */
		return -1;
	}

	fd = _alpm_open_archive(db->handle, dbpath, &buf,
			&archive, ALPM_ERR_DB_OPEN);
	if(fd < 0) {
		return -1;
	}
	est_count = estimate_package_count(&buf, archive);

	/* currently only .files dbs contain file lists - make flexible when required*/
	if(strcmp(db->handle->dbext, ".files") == 0) {
		/* files databases are about four times larger on average */
		est_count /= 4;
	}

	db->pkgcache = _alpm_pkghash_create(est_count);
	if(db->pkgcache == NULL) {
		db->handle->pm_errno = ALPM_ERR_MEMORY;
		count = -1;
		goto cleanup;
	}

	while(archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
		mode_t mode = archive_entry_mode(entry);
		if(S_ISDIR(mode)) {
			continue;
		} else {
			/* we have desc, depends or deltas - parse it */
			if(sync_db_read(db, archive, entry, &pkg) != 0) {
				_alpm_log(db->handle, ALPM_LOG_ERROR,
						_("could not parse package description file '%s' from db '%s'\n"),
						archive_entry_pathname(entry), db->treename);
				continue;
			}
		}
	}

	count = alpm_list_count(db->pkgcache->list);
	if(count > 0) {
		db->pkgcache->list = alpm_list_msort(db->pkgcache->list,
				(size_t)count, _alpm_pkg_cmp);
	}
	_alpm_log(db->handle, ALPM_LOG_DEBUG,
			"added %d packages to package cache for db '%s'\n",
			count, db->treename);

cleanup:
	_alpm_archive_read_free(archive);
	if(fd >= 0) {
		close(fd);
	}
	return count;
}
Пример #6
0
/** Unpack a list of files in an archive.
 * @param handle the context handle
 * @param path the archive to unpack
 * @param prefix where to extract the files
 * @param list a list of files within the archive to unpack or NULL for all
 * @param breakfirst break after the first entry found
 * @return 0 on success, 1 on failure
 */
int _alpm_unpack(alpm_handle_t *handle, const char *path, const char *prefix,
		alpm_list_t *list, int breakfirst)
{
	int ret = 0;
	mode_t oldmask;
	struct archive *archive;
	struct archive_entry *entry;
	struct stat buf;
	int fd, cwdfd;

	fd = _alpm_open_archive(handle, path, &buf, &archive, ALPM_ERR_PKG_OPEN);
	if(fd < 0) {
		return 1;
	}

	oldmask = umask(0022);

	/* save the cwd so we can restore it later */
	OPEN(cwdfd, ".", O_RDONLY | O_CLOEXEC);
	if(cwdfd < 0) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("could not get current working directory\n"));
	}

	/* just in case our cwd was removed in the upgrade operation */
	if(chdir(prefix) != 0) {
		_alpm_log(handle, ALPM_LOG_ERROR, _("could not change directory to %s (%s)\n"),
				prefix, strerror(errno));
		ret = 1;
		goto cleanup;
	}

	while(archive_read_next_header(archive, &entry) == ARCHIVE_OK) {
		const char *entryname;
		mode_t mode;

		entryname = archive_entry_pathname(entry);

		/* If specific files were requested, skip entries that don't match. */
		if(list) {
			char *entry_prefix = strdup(entryname);
			char *p = strstr(entry_prefix,"/");
			if(p) {
				*(p + 1) = '\0';
			}
			char *found = alpm_list_find_str(list, entry_prefix);
			free(entry_prefix);
			if(!found) {
				if(archive_read_data_skip(archive) != ARCHIVE_OK) {
					ret = 1;
					goto cleanup;
				}
				continue;
			} else {
				_alpm_log(handle, ALPM_LOG_DEBUG, "extracting: %s\n", entryname);
			}
		}

		mode = archive_entry_mode(entry);
		if(S_ISREG(mode)) {
			archive_entry_set_perm(entry, 0644);
		} else if(S_ISDIR(mode)) {
			archive_entry_set_perm(entry, 0755);
		}

		/* Extract the archive entry. */
		int readret = archive_read_extract(archive, entry, 0);
		if(readret == ARCHIVE_WARN) {
			/* operation succeeded but a non-critical error was encountered */
			_alpm_log(handle, ALPM_LOG_WARNING, _("warning given when extracting %s (%s)\n"),
					entryname, archive_error_string(archive));
		} else if(readret != ARCHIVE_OK) {
			_alpm_log(handle, ALPM_LOG_ERROR, _("could not extract %s (%s)\n"),
					entryname, archive_error_string(archive));
			ret = 1;
			goto cleanup;
		}

		if(breakfirst) {
			break;
		}
	}

cleanup:
	umask(oldmask);
	_alpm_archive_read_free(archive);
	close(fd);
	if(cwdfd >= 0) {
		if(fchdir(cwdfd) != 0) {
			_alpm_log(handle, ALPM_LOG_ERROR,
					_("could not restore working directory (%s)\n"), strerror(errno));
		}
		close(cwdfd);
	}

	return ret;
}