pacman/lib/libalpm/sync.c

/*
 *  sync.c
 *
 *  Copyright (c) 2002-2007 by Judd Vinet <jvinet@zeroflux.org>
 *  Copyright (c) 2005 by Aurelien Foret <orelien@chez.com>
 *  Copyright (c) 2005 by Christian Hamar <krics@linuxforum.hu>
 *  Copyright (c) 2005, 2006 by Miklos Vajna <vmiklos@frugalware.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"

#include <sys/types.h> /* off_t */
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <string.h>
#include <stdint.h> /* intmax_t */
#include <unistd.h>
#include <time.h>
#include <dirent.h>

/* libalpm */
#include "sync.h"
#include "alpm_list.h"
#include "log.h"
#include "package.h"
#include "db.h"
#include "cache.h"
#include "deps.h"
#include "conflict.h"
#include "trans.h"
#include "util.h"
#include "handle.h"
#include "alpm.h"
#include "dload.h"
#include "delta.h"

/* Find recommended replacements for packages during a sync.
 */
static int find_replacements(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync)
{
	alpm_list_t *i, *j, *k; /* wow */

	ALPM_LOG_FUNC;

	/* check for "recommended" package replacements */
	_alpm_log(PM_LOG_DEBUG, "checking for package replacements\n");
	for(i = dbs_sync; i; i = i->next) {
		pmdb_t *db = i->data;

		/* for each db, check each package's REPLACES list */
		for(j = _alpm_db_get_pkgcache(db); j; j = j->next) {
			pmpkg_t *spkg = j->data;

			for(k = alpm_pkg_get_replaces(spkg); k; k = k->next) {
				const char *replacement = k->data;

				pmpkg_t *lpkg = _alpm_db_get_pkgfromcache(db_local, replacement);
				if(!lpkg) {
					continue;
				}

				_alpm_log(PM_LOG_DEBUG, "checking replacement '%s' for package '%s'\n",
						replacement, spkg->name);
				/* ignore if EITHER the local or replacement package are to be ignored */
				if(_alpm_pkg_should_ignore(spkg) || _alpm_pkg_should_ignore(lpkg)) {
					_alpm_log(PM_LOG_WARNING, _("%s-%s: ignoring package upgrade (to be replaced by %s-%s)\n"),
										alpm_pkg_get_name(lpkg), alpm_pkg_get_version(lpkg),
										alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
				} else {
					int doreplace = 0;
					QUESTION(trans, PM_TRANS_CONV_REPLACE_PKG, lpkg, spkg, db->treename, &doreplace);
					if(!doreplace) {
						continue;
					}

					/* if confirmed, add this to the 'final' list, designating 'lpkg' as
					 * the package to replace.
					 */

					/* check if spkg->name is already in the packages list. */
					/* TODO: same package name doesn't mean same package */
					pmpkg_t *tpkg = _alpm_pkg_find(trans->packages, alpm_pkg_get_name(spkg));
					if(tpkg) {
						/* found it -- just append to the removes list */
						tpkg->removes = alpm_list_add(tpkg->removes, lpkg);
						/* check the to-be-replaced package's reason field */
						if(alpm_pkg_get_reason(lpkg) == PM_PKG_REASON_EXPLICIT) {
							tpkg->reason = PM_PKG_REASON_EXPLICIT;
						}
					} else {
						/* none found -- enter pkg into the final sync list */
						/* copy over reason */
						spkg->reason = alpm_pkg_get_reason(lpkg);
						spkg->removes = alpm_list_add(NULL, lpkg);
						_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
									alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
						trans->packages = alpm_list_add(trans->packages, spkg);
					}
					_alpm_log(PM_LOG_DEBUG, "%s-%s elected for removal (to be replaced by %s-%s)\n",
							alpm_pkg_get_name(lpkg), alpm_pkg_get_version(lpkg),
							alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
				}
			}
		}
	}
	return(0);
}

/** Check for new version of pkg in sync repos
 * (only the first occurrence is considered in sync)
 */
pmpkg_t SYMEXPORT *alpm_sync_newversion(pmpkg_t *pkg, alpm_list_t *dbs_sync)
{
	alpm_list_t *i;
	pmpkg_t *spkg = NULL;
	int cmp;

	for(i = dbs_sync; !spkg && i; i = i->next) {
		spkg = _alpm_db_get_pkgfromcache(i->data, alpm_pkg_get_name(pkg));
	}

	if(spkg == NULL) {
		_alpm_log(PM_LOG_DEBUG, "'%s' not found in sync db => no upgrade\n",
				alpm_pkg_get_name(pkg));
		return(NULL);
	}

	/* compare versions and see if spkg is an upgrade */
	cmp = _alpm_pkg_compare_versions(spkg, pkg);
	if(cmp > 0) {
		_alpm_log(PM_LOG_DEBUG, "new version of '%s' found (%s => %s)\n",
					alpm_pkg_get_name(pkg), alpm_pkg_get_version(pkg),
					alpm_pkg_get_version(spkg));
		return(spkg);
	}
	if (cmp < 0) {
			pmdb_t *db = spkg->origin_data.db;
			_alpm_log(PM_LOG_WARNING, _("%s: local (%s) is newer than %s (%s)\n"),
					alpm_pkg_get_name(pkg), alpm_pkg_get_version(pkg),
					alpm_db_get_name(db), alpm_pkg_get_version(spkg));
	}
	return(NULL);
}

int _alpm_sync_sysupgrade(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync)
{
	alpm_list_t *i, *j, *replaced = NULL;

	ALPM_LOG_FUNC;

	/* check for "recommended" package replacements */
	if(find_replacements(trans, db_local, dbs_sync)) {
		return(-1);
	}

	/* compute the to-be-replaced packages for efficiency */
	for(i = trans->packages; i; i = i->next) {
		pmpkg_t *spkg = i->data;
		for(j = spkg->removes; j; j = j->next) {
			replaced = alpm_list_add(replaced, j->data);
		}
	}

	/* for all not-replaced local package we check for upgrade */
	_alpm_log(PM_LOG_DEBUG, "checking for package upgrades\n");
	for(i = _alpm_db_get_pkgcache(db_local); i; i = i->next) {
		pmpkg_t *local = i->data;

		if(_alpm_pkg_find(replaced, alpm_pkg_get_name(local))) {
			_alpm_log(PM_LOG_DEBUG, "'%s' is already elected for removal -- skipping\n",
					alpm_pkg_get_name(local));
			continue;
		}

		pmpkg_t *spkg = alpm_sync_newversion(local, dbs_sync);
		if(spkg) {
			/* we found a new version */
			/* skip packages in IgnorePkg or in IgnoreGroup */
			if(_alpm_pkg_should_ignore(spkg)) {
				_alpm_log(PM_LOG_WARNING, _("%s: ignoring package upgrade (%s => %s)\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local),
						alpm_pkg_get_version(spkg));
				continue;
			}

			/* add the upgrade package to the target list */
			if(_alpm_pkg_find(trans->packages, alpm_pkg_get_name(spkg))) {
				/* avoid duplicated targets */
				continue;
			}
			_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
							alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
			/* we don't set any reason here,
			   it will be calculated from local package in add_commit */
			trans->packages = alpm_list_add(trans->packages, spkg);
		}
	}

	alpm_list_free(replaced);
	return(0);
}

int _alpm_sync_addtarget(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync, char *name)
{
	char *targline;
	char *targ;
	alpm_list_t *j;
	pmpkg_t *local, *spkg;
	pmdepend_t *dep; /* provisions and dependencies are also allowed */

	ALPM_LOG_FUNC;

	ASSERT(db_local != NULL, RET_ERR(PM_ERR_DB_NULL, -1));
	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));
	ASSERT(name != NULL, RET_ERR(PM_ERR_WRONG_ARGS, -1));

	STRDUP(targline, name, RET_ERR(PM_ERR_MEMORY, -1));
	targ = strchr(targline, '/');
	if(targ) {
		/* we are looking for a package in a specific database */
		alpm_list_t *dbs = NULL;
		*targ = '\0';
		targ++;
		_alpm_log(PM_LOG_DEBUG, "searching for target '%s' in repo '%s'\n", targ, targline);
		for(j = dbs_sync; j; j = j->next) {
			pmdb_t *db = j->data;
			if(strcmp(db->treename, targline) == 0) {
				dbs = alpm_list_add(NULL, db);
				break;
			}
		}
		if(dbs == NULL) {
			_alpm_log(PM_LOG_ERROR, _("repository '%s' not found\n"), targline);
			FREE(targline);
			RET_ERR(PM_ERR_PKG_REPO_NOT_FOUND, -1);
		}
		dep = _alpm_splitdep(targ);
		spkg = _alpm_resolvedep(dep, dbs, NULL, 1);
		_alpm_dep_free(dep);
		alpm_list_free(dbs);
	} else {
		dep = _alpm_splitdep(targline);
		spkg = _alpm_resolvedep(dep, dbs_sync, NULL, 1);
		_alpm_dep_free(dep);
	}
	FREE(targline);

	if(spkg == NULL) {
		/* pm_errno is set by _alpm_resolvedep */
		return(-1);
	}

	if(_alpm_pkg_find(trans->packages, alpm_pkg_get_name(spkg))) {
		RET_ERR(PM_ERR_TRANS_DUP_TARGET, -1);
	}

	local = _alpm_db_get_pkgfromcache(db_local, alpm_pkg_get_name(spkg));
	if(local) {
		int cmp = _alpm_pkg_compare_versions(spkg, local);
		if(cmp == 0) {
			if(trans->flags & PM_TRANS_FLAG_NEEDED) {
				/* with the NEEDED flag, packages up to date are not reinstalled */
				_alpm_log(PM_LOG_WARNING, _("%s-%s is up to date -- skipping\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local));
				return(0);
			} else {
				_alpm_log(PM_LOG_WARNING, _("%s-%s is up to date -- reinstalling\n"),
						alpm_pkg_get_name(local), alpm_pkg_get_version(local));

			}
		} else if(cmp < 0) {
			/* local version is newer */
			_alpm_log(PM_LOG_WARNING, _("downgrading package %s (%s => %s)\n"),
					alpm_pkg_get_name(local), alpm_pkg_get_version(local),
					alpm_pkg_get_version(spkg));
		}
	}

	/* add the package to the transaction */
	spkg->reason = PM_PKG_REASON_EXPLICIT;
	_alpm_log(PM_LOG_DEBUG, "adding package %s-%s to the transaction targets\n",
						alpm_pkg_get_name(spkg), alpm_pkg_get_version(spkg));
	trans->packages = alpm_list_add(trans->packages, spkg);

	return(0);
}

/** Compute the size of the files that will be downloaded to install a
 * package.
 * @param newpkg the new package to upgrade to
 */
static int compute_download_size(pmpkg_t *newpkg)
{
	const char *fname;
	char *fpath;
	off_t size = 0;

	fname = alpm_pkg_get_filename(newpkg);
	ASSERT(fname != NULL, RET_ERR(PM_ERR_PKG_INVALID_NAME, -1));
	fpath = _alpm_filecache_find(fname);

	if(fpath) {
		FREE(fpath);
		size = 0;
	} else if(handle->usedelta) {
		off_t dltsize;
		off_t pkgsize = alpm_pkg_get_size(newpkg);

		dltsize = _alpm_shortest_delta_path(
			alpm_pkg_get_deltas(newpkg),
			alpm_pkg_get_filename(newpkg),
			&newpkg->delta_path);

		if(newpkg->delta_path && (dltsize < pkgsize * MAX_DELTA_RATIO)) {
			_alpm_log(PM_LOG_DEBUG, "using delta size\n");
			size = dltsize;
		} else {
			_alpm_log(PM_LOG_DEBUG, "using package size\n");
			size = alpm_pkg_get_size(newpkg);
			alpm_list_free(newpkg->delta_path);
			newpkg->delta_path = NULL;
		}
	} else {
		size = alpm_pkg_get_size(newpkg);
	}

	_alpm_log(PM_LOG_DEBUG, "setting download size %jd for pkg %s\n",
			(intmax_t)size, alpm_pkg_get_name(newpkg));

	newpkg->download_size = size;
	return(0);
}

int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync, alpm_list_t **data)
{
	alpm_list_t *deps = NULL;
	alpm_list_t *unresolvable = NULL;
	alpm_list_t *remove = NULL; /* allow checkdeps usage with trans->packages */
	alpm_list_t *i, *j;
	int ret = 0;

	ALPM_LOG_FUNC;

	ASSERT(db_local != NULL, RET_ERR(PM_ERR_DB_NULL, -1));
	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));

	if(data) {
		*data = NULL;
	}

	if(!(trans->flags & PM_TRANS_FLAG_NODEPS)) {
		alpm_list_t *resolved = NULL; /* target list after resolvedeps */

		/* Build up list by repeatedly resolving each transaction package */
		/* Resolve targets dependencies */
		EVENT(trans, PM_TRANS_EVT_RESOLVEDEPS_START, NULL, NULL);
		_alpm_log(PM_LOG_DEBUG, "resolving target's dependencies\n");

		/* build remove list for resolvedeps */
		for(i = trans->packages; i; i = i->next) {
			pmpkg_t *spkg = i->data;
			for(j = spkg->removes; j; j = j->next) {
				remove = alpm_list_add(remove, j->data);
			}
		}

		/* Resolve packages in the transaction one at a time, in addtion
		   building up a list of packages which could not be resolved. */
		for(i = trans->packages; i; i = i->next) {
			pmpkg_t *pkg = i->data;
			if(_alpm_resolvedeps(db_local, dbs_sync, pkg, &resolved, remove, data) == -1) {
				unresolvable = alpm_list_add(unresolvable, pkg);
			}
			/* Else, [resolved] now additionally contains [pkg] and all of its
			   dependencies not already on the list */
		}

		/* If there were unresolvable top-level packages, prompt the user to
		   see if they'd like to ignore them rather than failing the sync */
		if(unresolvable != NULL) {
			int remove_unresolvable = 0;
			QUESTION(handle->trans, PM_TRANS_CONV_REMOVE_PKGS, unresolvable,
					NULL, NULL, &remove_unresolvable);
			if (remove_unresolvable) {
				/* User wants to remove the unresolvable packages from the
				   transaction. The packages will be removed from the actual
				   transaction when the transaction packages are replaced with a
				   dependency-reordered list below */
				pm_errno = 0; /* pm_errno was set by resolvedeps */
				if(data) {
					alpm_list_free_inner(*data, (alpm_list_fn_free)_alpm_depmiss_free);
					alpm_list_free(*data);
					*data = NULL;
				}
			} else {
				/* pm_errno is set by resolvedeps */
				alpm_list_free(resolved);
				ret = -1;
				goto cleanup;
			}
		}

		/* Unresolvable packages will be removed from the target list, so
		   we free the transaction specific field: pkg->removes */
		for(i = unresolvable; i; i = i->next) {
			pmpkg_t *pkg = i->data;
			alpm_list_free(pkg->removes);
			pkg->removes = NULL;
		}

		/* Set DEPEND reason for pulled packages */
		for(i = resolved; i; i = i->next) {
			pmpkg_t *pkg = i->data;
			if(!_alpm_pkg_find(trans->packages, pkg->name)) {
				pkg->reason = PM_PKG_REASON_DEPEND;
			}
		}

		/* re-order w.r.t. dependencies */
		alpm_list_free(trans->packages);
		trans->packages = _alpm_sortbydeps(resolved, 0);
		alpm_list_free(resolved);

		EVENT(trans, PM_TRANS_EVT_RESOLVEDEPS_DONE, NULL, NULL);
	}

	if(!(trans->flags & PM_TRANS_FLAG_NOCONFLICTS)) {
		/* check for inter-conflicts and whatnot */
		EVENT(trans, PM_TRANS_EVT_INTERCONFLICTS_START, NULL, NULL);

		_alpm_log(PM_LOG_DEBUG, "looking for conflicts\n");

		/* 1. check for conflicts in the target list */
		_alpm_log(PM_LOG_DEBUG, "check targets vs targets\n");
		deps = _alpm_innerconflicts(trans->packages);

		for(i = deps; i; i = i->next) {
			pmconflict_t *conflict = i->data;
			pmpkg_t *rsync, *sync, *sync1, *sync2;

			/* have we already removed one of the conflicting targets? */
			sync1 = _alpm_pkg_find(trans->packages, conflict->package1);
			sync2 = _alpm_pkg_find(trans->packages, conflict->package2);
			if(!sync1 || !sync2) {
				continue;
			}

			_alpm_log(PM_LOG_DEBUG, "conflicting packages in the sync list: '%s' <-> '%s'\n",
					conflict->package1, conflict->package2);

			/* if sync1 provides sync2, we remove sync2 from the targets, and vice versa */
			pmdepend_t *dep1 = _alpm_splitdep(conflict->package1);
			pmdepend_t *dep2 = _alpm_splitdep(conflict->package2);
			if(alpm_depcmp(sync1, dep2)) {
				rsync = sync2;
				sync = sync1;
			} else if(alpm_depcmp(sync2, dep1)) {
				rsync = sync1;
				sync = sync2;
			} else {
				_alpm_log(PM_LOG_ERROR, _("unresolvable package conflicts detected\n"));
				pm_errno = PM_ERR_CONFLICTING_DEPS;
				ret = -1;
				if(data) {
					pmconflict_t *newconflict = _alpm_conflict_dup(conflict);
					if(newconflict) {
						*data = alpm_list_add(*data, newconflict);
					}
				}
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
				alpm_list_free(deps);
				_alpm_dep_free(dep1);
				_alpm_dep_free(dep2);
				goto cleanup;
			}
			_alpm_dep_free(dep1);
			_alpm_dep_free(dep2);

			/* Prints warning */
			_alpm_log(PM_LOG_WARNING,
					_("removing '%s' from target list because it conflicts with '%s'\n"),
					rsync->name, sync->name);
			alpm_list_free(rsync->removes); /* rsync is not transaction target anymore */
			rsync->removes = NULL;
			trans->packages = alpm_list_remove(trans->packages, rsync, _alpm_pkg_cmp, NULL);
			continue;
		}

		alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
		alpm_list_free(deps);
		deps = NULL;

		/* 2. we check for target vs db conflicts (and resolve)*/
		_alpm_log(PM_LOG_DEBUG, "check targets vs db and db vs targets\n");
		deps = _alpm_outerconflicts(db_local, trans->packages);

		for(i = deps; i; i = i->next) {
			pmconflict_t *conflict = i->data;

			/* if conflict->package2 (the local package) is not elected for removal,
			   we ask the user */
			int found = 0;
			for(j = trans->packages; j && !found; j = j->next) {
				pmpkg_t *spkg = j->data;
				if(_alpm_pkg_find(spkg->removes, conflict->package2)) {
					found = 1;
				}
			}
			if(found) {
				continue;
			}

			_alpm_log(PM_LOG_DEBUG, "package '%s' conflicts with '%s'\n",
					conflict->package1, conflict->package2);

			pmpkg_t *sync = _alpm_pkg_find(trans->packages, conflict->package1);
			pmpkg_t *local = _alpm_db_get_pkgfromcache(db_local, conflict->package2);
			int doremove = 0;
			QUESTION(trans, PM_TRANS_CONV_CONFLICT_PKG, conflict->package1,
								conflict->package2, NULL, &doremove);
			if(doremove) {
				/* append to the removes list */
				_alpm_log(PM_LOG_DEBUG, "electing '%s' for removal\n", conflict->package2);
				sync->removes = alpm_list_add(sync->removes, local);
			} else { /* abort */
				_alpm_log(PM_LOG_ERROR, _("unresolvable package conflicts detected\n"));
				pm_errno = PM_ERR_CONFLICTING_DEPS;
				ret = -1;
				if(data) {
					pmconflict_t *newconflict = _alpm_conflict_dup(conflict);
					if(newconflict) {
						*data = alpm_list_add(*data, newconflict);
					}
				}
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
				alpm_list_free(deps);
				goto cleanup;
			}
		}
		EVENT(trans, PM_TRANS_EVT_INTERCONFLICTS_DONE, NULL, NULL);
		alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_conflict_free);
		alpm_list_free(deps);
	}

	if(!(trans->flags & PM_TRANS_FLAG_NODEPS)) {
		/* rebuild remove list */
		alpm_list_free(remove);
		remove = NULL;
		for(i = trans->packages; i; i = i->next) {
			pmpkg_t *spkg = i->data;
			for(j = spkg->removes; j; j = j->next) {
				remove = alpm_list_add(remove, j->data);
			}
		}

		_alpm_log(PM_LOG_DEBUG, "checking dependencies\n");
		deps = alpm_checkdeps(_alpm_db_get_pkgcache(db_local), 1, remove, trans->packages);
		if(deps) {
			pm_errno = PM_ERR_UNSATISFIED_DEPS;
			ret = -1;
			if(data) {
				*data = deps;
			} else {
				alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free);
				alpm_list_free(deps);
			}
			goto cleanup;
		}
	}
	for(i = trans->packages; i; i = i->next) {
		/* update download size field */
		pmpkg_t *spkg = i->data;
		if(compute_download_size(spkg) != 0) {
			ret = -1;
			goto cleanup;
		}
	}

cleanup:
	alpm_list_free(remove);
	alpm_list_free(unresolvable);

	return(ret);
}

/** Returns the size of the files that will be downloaded to install a
 * package.
 * @param newpkg the new package to upgrade to
 * @return the size of the download
 */
off_t SYMEXPORT alpm_pkg_download_size(pmpkg_t *newpkg)
{
	return(newpkg->download_size);
}

static int endswith(char *filename, char *extension)
{
	char *s = filename + strlen(filename) - strlen(extension);
	return (strcmp(s, extension) == 0);
}

/** Applies delta files to create an upgraded package file.
 *
 * All intermediate files are deleted, leaving only the starting and
 * ending package files.
 *
 * @param trans the transaction
 *
 * @return 0 if all delta files were able to be applied, 1 otherwise.
 */
static int apply_deltas(pmtrans_t *trans)
{
	alpm_list_t *i;
	int ret = 0;
	const char *cachedir = _alpm_filecache_setup();

	for(i = trans->packages; i; i = i->next) {
		pmpkg_t *spkg = i->data;
		alpm_list_t *delta_path = spkg->delta_path;
		alpm_list_t *dlts = NULL;

		if(!delta_path) {
			continue;
		}

		for(dlts = delta_path; dlts; dlts = dlts->next) {
			pmdelta_t *d = dlts->data;
			char *delta, *from, *to;
			char command[PATH_MAX];
			int len = 0;

			delta = _alpm_filecache_find(d->delta);
			/* the initial package might be in a different cachedir */
			if(dlts == delta_path) {
				from = _alpm_filecache_find(d->from);
			} else {
				/* len = cachedir len + from len + '/' + null */
				len = strlen(cachedir) + strlen(d->from) + 2;
				CALLOC(from, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, 1));
				snprintf(from, len, "%s/%s", cachedir, d->from);
			}
			len = strlen(cachedir) + strlen(d->to) + 2;
			CALLOC(to, len, sizeof(char), RET_ERR(PM_ERR_MEMORY, 1));
			snprintf(to, len, "%s/%s", cachedir, d->to);

			/* build the patch command */
			/* compression command */
			char *compress = "cat";
			if(endswith(to, ".gz")) {
				compress = "gzip -n";
			} else if(endswith(to, ".bz2")) {
				compress = "bzip";
			}
			/* -R for disabling external recompression, -c for sending to stdout */
			snprintf(command, PATH_MAX, "xdelta3 -d -q -R -c -s %s %s | %s > %s", from, delta, compress, to);

			_alpm_log(PM_LOG_DEBUG, "command: %s\n", command);

			EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_START, d->to, d->delta);

			int retval = system(command);
			if(retval == 0) {
				EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_DONE, NULL, NULL);

				/* delete the delta file */
				unlink(delta);

				/* Delete the 'from' package but only if it is an intermediate
				 * package. The starting 'from' package should be kept, just
				 * as if deltas were not used. */
				if(dlts != delta_path) {
					unlink(from);
				}
			}
			FREE(from);
			FREE(to);
			FREE(delta);

			if(retval != 0) {
				/* one delta failed for this package, cancel the remaining ones */
				EVENT(trans, PM_TRANS_EVT_DELTA_PATCH_FAILED, NULL, NULL);
				ret = 1;
				break;
			}
		}
	}

	return(ret);
}

/** Compares the md5sum of a file to the expected value.
 *
 * If the md5sum does not match, the user is asked whether the file
 * should be deleted.
 *
 * @param trans the transaction
 * @param filename the filename of the file to test
 * @param md5sum the expected md5sum of the file
 *
 * @return 0 if the md5sum matched, 1 if not, -1 in case of errors
 */
static int test_md5sum(pmtrans_t *trans, const char *filename,
		const char *md5sum)
{
	char *filepath;
	int ret;

	filepath = _alpm_filecache_find(filename);

	ret = _alpm_test_md5sum(filepath, md5sum);

	if(ret == 1) {
		int doremove = 0;
		QUESTION(trans, PM_TRANS_CONV_CORRUPTED_PKG, (char *)filename,
				NULL, NULL, &doremove);
		if(doremove) {
			unlink(filepath);
		}
	}

	FREE(filepath);

	return(ret);
}

int _alpm_sync_commit(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t **data)
{
	alpm_list_t *i, *j, *files = NULL;
	alpm_list_t *deltas = NULL;
	pmtrans_t *tr_remove = NULL, *tr_upgrade = NULL;
	int replaces = 0;
	int errors = 0;
	const char *cachedir = NULL;
	int ret = -1;

	ALPM_LOG_FUNC;

	ASSERT(trans != NULL, RET_ERR(PM_ERR_TRANS_NULL, -1));

	cachedir = _alpm_filecache_setup();
	trans->state = STATE_DOWNLOADING;

	/* Total progress - figure out the total download size if required to
	 * pass to the callback. This function is called once, and it is up to the
	 * frontend to compute incremental progress. */
	if(handle->totaldlcb) {
		off_t total_size = (off_t)0;
		/* sum up the download size for each package and store total */
		for(i = trans->packages; i; i = i->next) {
			pmpkg_t *spkg = i->data;
			total_size += spkg->download_size;
		}
		handle->totaldlcb(total_size);
	}

	/* group sync records by repository and download */
	for(i = handle->dbs_sync; i; i = i->next) {
		pmdb_t *current = i->data;

		for(j = trans->packages; j; j = j->next) {
			pmpkg_t *spkg = j->data;
			pmdb_t *dbs = spkg->origin_data.db;

			if(current == dbs) {
				const char *fname = NULL;

				fname = alpm_pkg_get_filename(spkg);
				ASSERT(fname != NULL, RET_ERR(PM_ERR_PKG_INVALID_NAME, -1));
				alpm_list_t *delta_path = spkg->delta_path;
				if(delta_path) {
					/* using deltas */
					alpm_list_t *dlts = NULL;

					for(dlts = delta_path; dlts; dlts = dlts->next) {
						pmdelta_t *d = dlts->data;

						if(d->download_size != 0) {
							/* add the delta filename to the download list if needed */
							files = alpm_list_add(files, strdup(d->delta));
						}

						/* keep a list of all the delta files for md5sums */
						deltas = alpm_list_add(deltas, d);
					}

				} else {
					/* not using deltas */
					if(spkg->download_size != 0) {
						/* add the filename to the download list if needed */
						files = alpm_list_add(files, strdup(fname));
					}
				}

			}
		}

		if(files) {
			EVENT(trans, PM_TRANS_EVT_RETRIEVE_START, current->treename, NULL);
			if(_alpm_download_files(files, current->servers, cachedir)) {
				_alpm_log(PM_LOG_WARNING, _("failed to retrieve some files from %s\n"),
						current->treename);
				pm_errno = PM_ERR_RETRIEVE;
				goto error;
			}
			FREELIST(files);
		}
	}

	/* clear out value to let callback know we are done */
	if(handle->totaldlcb) {
		handle->totaldlcb(0);
	}

	/* if we have deltas to work with */
	if(handle->usedelta && deltas) {
		int ret = 0;
		errors = 0;
		/* Check integrity of deltas */
		EVENT(trans, PM_TRANS_EVT_DELTA_INTEGRITY_START, NULL, NULL);

		for(i = deltas; i; i = i->next) {
			pmdelta_t *d = alpm_list_getdata(i);
			const char *filename = alpm_delta_get_filename(d);
			const char *md5sum = alpm_delta_get_md5sum(d);

			if(test_md5sum(trans, filename, md5sum) != 0) {
				errors++;
				*data = alpm_list_add(*data, strdup(filename));
			}
		}
		if(errors) {
			pm_errno = PM_ERR_DLT_INVALID;
			goto error;
		}
		EVENT(trans, PM_TRANS_EVT_DELTA_INTEGRITY_DONE, NULL, NULL);

		/* Use the deltas to generate the packages */
		EVENT(trans, PM_TRANS_EVT_DELTA_PATCHES_START, NULL, NULL);
		ret = apply_deltas(trans);
		EVENT(trans, PM_TRANS_EVT_DELTA_PATCHES_DONE, NULL, NULL);

		if(ret) {
			pm_errno = PM_ERR_DLT_PATCHFAILED;
			goto error;
		}
	}

	/* Check integrity of packages */
	EVENT(trans, PM_TRANS_EVT_INTEGRITY_START, NULL, NULL);

	errors = 0;
	for(i = trans->packages; i; i = i->next) {
		pmpkg_t *spkg = i->data;
		const char *filename = alpm_pkg_get_filename(spkg);
		const char *md5sum = alpm_pkg_get_md5sum(spkg);

		if(test_md5sum(trans, filename, md5sum) != 0) {
			errors++;
			*data = alpm_list_add(*data, strdup(filename));
		}
	}
	if(errors) {
		pm_errno = PM_ERR_PKG_INVALID;
		goto error;
	}
	EVENT(trans, PM_TRANS_EVT_INTEGRITY_DONE, NULL, NULL);
	if(trans->flags & PM_TRANS_FLAG_DOWNLOADONLY) {
		return(0);
	}

	trans->state = STATE_COMMITING;

	/* Create remove and upgrade transactions */
	tr_remove = _alpm_trans_new();
	if(tr_remove == NULL) {
		_alpm_log(PM_LOG_ERROR, _("could not create removal transaction\n"));
		goto error;
	}
	tr_upgrade = _alpm_trans_new();
	if(tr_upgrade == NULL) {
		_alpm_log(PM_LOG_ERROR, _("could not create transaction\n"));
		goto error;
	}

	if(_alpm_trans_init(tr_remove, PM_TRANS_TYPE_REMOVE, PM_TRANS_FLAG_NODEPS, NULL, NULL, NULL) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not initialize the removal transaction\n"));
		goto error;
	}
	if(_alpm_trans_init(tr_upgrade, PM_TRANS_TYPE_UPGRADE, trans->flags, trans->cb_event, trans->cb_conv, trans->cb_progress) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not initialize transaction\n"));
		goto error;
	}

	/* adding targets */
	for(i = trans->packages; i; i = i->next) {
		pmpkg_t *spkg = i->data;
		alpm_list_t *j;
		/* remove transaction */
		for(j = spkg->removes; j; j = j->next) {
			pmpkg_t *pkg = j->data;
			if(!_alpm_pkg_find(tr_remove->packages, pkg->name)) {
				if(_alpm_trans_addtarget(tr_remove, pkg->name) == -1) {
					goto error;
				}
				replaces++;
			}
		}
		/* upgrade transaction */
		const char *fname;
		char *fpath;

		fname = alpm_pkg_get_filename(spkg);
		if(fname == NULL) {
			goto error;
		}
		/* Loop through the cache dirs until we find a matching file */
		fpath = _alpm_filecache_find(fname);

		if(_alpm_trans_addtarget(tr_upgrade, fpath) == -1) {
			FREE(fpath);
			goto error;
		}
		FREE(fpath);

		/* using alpm_list_last() is ok because addtarget() adds the new target at the
		 * end of the tr->packages list */
		pmpkg_t *ipkg = alpm_list_last(tr_upgrade->packages)->data;
		ipkg->reason = spkg->reason;
	}

	/* fileconflict check */
	if(!(trans->flags & PM_TRANS_FLAG_FORCE)) {
		EVENT(trans, PM_TRANS_EVT_FILECONFLICTS_START, NULL, NULL);

		_alpm_log(PM_LOG_DEBUG, "looking for file conflicts\n");
		alpm_list_t *conflict = _alpm_db_find_fileconflicts(db_local, tr_upgrade,
								    tr_upgrade->packages, tr_remove->packages);
		if(conflict) {
			pm_errno = PM_ERR_FILE_CONFLICTS;
			if(data) {
				*data = conflict;
			} else {
				alpm_list_free_inner(conflict, (alpm_list_fn_free)_alpm_fileconflict_free);
				alpm_list_free(conflict);
			}
			goto error;
		}

		EVENT(trans, PM_TRANS_EVT_FILECONFLICTS_DONE, NULL, NULL);
	}

	/* remove conflicting and to-be-replaced packages */
	if(replaces) {
		_alpm_log(PM_LOG_DEBUG, "removing conflicting and to-be-replaced packages\n");
		if(_alpm_trans_prepare(tr_remove, data) == -1) {
			_alpm_log(PM_LOG_ERROR, _("could not prepare removal transaction\n"));
			goto error;
		}
		/* we want the frontend to be aware of commit details */
		tr_remove->cb_event = trans->cb_event;
		if(_alpm_trans_commit(tr_remove, NULL) == -1) {
			_alpm_log(PM_LOG_ERROR, _("could not commit removal transaction\n"));
			goto error;
		}
	}

	/* install targets */
	_alpm_log(PM_LOG_DEBUG, "installing packages\n");
	/* add_prepare is not needed */
	if(_alpm_trans_commit(tr_upgrade, NULL) == -1) {
		_alpm_log(PM_LOG_ERROR, _("could not commit transaction\n"));
		goto error;
	}
	ret = 0;

error:
	FREELIST(files);
	alpm_list_free(deltas);
	_alpm_trans_free(tr_remove);
	_alpm_trans_free(tr_upgrade);
	return(ret);
}

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