be_sync.c

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/*
 *  be_sync.c : backend for sync databases
 *
 *  Copyright (c) 2006-2011 Pacman Development Team <pacman-dev@archlinux.org>
 *  Copyright (c) 2002-2006 by Judd Vinet <jvinet@zeroflux.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 <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

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

/* libalpm */
#include "util.h"
#include "log.h"
#include "alpm.h"
#include "alpm_list.h"
#include "package.h"
#include "handle.h"
#include "delta.h"
#include "deps.h"
#include "dload.h"

static char *get_sync_dir(alpm_handle_t *handle)
{
    size_t len = strlen(handle->dbpath) + 6;
    char *syncpath;
    struct stat buf;

    MALLOC(syncpath, len, RET_ERR(handle, ALPM_ERR_MEMORY, NULL));
    sprintf(syncpath, "%s%s", handle->dbpath, "sync/");

    if(stat(syncpath, &buf) != 0) {
        _alpm_log(handle, ALPM_LOG_DEBUG, "database dir '%s' does not exist, creating it\n",
                syncpath);
        if(_alpm_makepath(syncpath) != 0) {
            free(syncpath);
            RET_ERR(handle, ALPM_ERR_SYSTEM, NULL);
        }
    } else if(!S_ISDIR(buf.st_mode)) {
        _alpm_log(handle, ALPM_LOG_WARNING, _("removing invalid file: %s\n"), syncpath);
        if(unlink(syncpath) != 0 || _alpm_makepath(syncpath) != 0) {
            free(syncpath);
            RET_ERR(handle, ALPM_ERR_SYSTEM, NULL);
        }
    }

    return syncpath;
}

static int sync_db_validate(alpm_db_t *db)
{
    alpm_siglevel_t level;
    const char *dbpath;

    if(db->status & DB_STATUS_VALID || db->status & DB_STATUS_MISSING) {
        return 0;
    }
    if(db->status & DB_STATUS_INVALID) {
        db->handle->pm_errno = ALPM_ERR_DB_INVALID_SIG;
        return -1;
    }

    dbpath = _alpm_db_path(db);
    if(!dbpath) {
        /* pm_errno set in _alpm_db_path() */
        return -1;
    }

    /* we can skip any validation if the database doesn't exist */
    if(access(dbpath, R_OK) != 0 && errno == ENOENT) {
        db->status &= ~DB_STATUS_EXISTS;
        db->status |= DB_STATUS_MISSING;
        _alpm_log(db->handle, ALPM_LOG_WARNING,
                "database file for '%s' does not exist\n", db->treename);
        goto valid;
    }
    db->status |= DB_STATUS_EXISTS;
    db->status &= ~DB_STATUS_MISSING;

    /* this takes into account the default verification level if UNKNOWN
     * was assigned to this db */
    level = alpm_db_get_siglevel(db);

    if(level & ALPM_SIG_DATABASE) {
        int retry, ret;
        do {
            retry = 0;
            alpm_siglist_t *siglist;
            ret = _alpm_check_pgp_helper(db->handle, dbpath, NULL,
                    level & ALPM_SIG_DATABASE_OPTIONAL, level & ALPM_SIG_DATABASE_MARGINAL_OK,
                    level & ALPM_SIG_DATABASE_UNKNOWN_OK, &siglist);
            if(ret) {
                retry = _alpm_process_siglist(db->handle, db->treename, siglist,
                        level & ALPM_SIG_DATABASE_OPTIONAL, level & ALPM_SIG_DATABASE_MARGINAL_OK,
                        level & ALPM_SIG_DATABASE_UNKNOWN_OK);
            }
            alpm_siglist_cleanup(siglist);
            free(siglist);
        } while(retry);

        if(ret) {
            db->status &= ~DB_STATUS_VALID;
            db->status |= DB_STATUS_INVALID;
            db->handle->pm_errno = ALPM_ERR_DB_INVALID_SIG;
            return 1;
        }
    }

valid:
    db->status |= DB_STATUS_VALID;
    db->status &= ~DB_STATUS_INVALID;
    return 0;
}

/** Update a package database
 *
 * An update of the package database \a db will be attempted. Unless
 * \a force is true, the update will only be performed if the remote
 * database was modified since the last update.
 *
 * This operation requires a database lock, and will return an applicable error
 * if the lock could not be obtained.
 *
 * Example:
 * @code
 * alpm_list_t *syncs = alpm_option_get_syncdbs();
 * for(i = syncs; i; i = alpm_list_next(i)) {
 *     alpm_db_t *db = alpm_list_getdata(i);
 *     result = alpm_db_update(0, db);
 *
 *     if(result < 0) {
 *         printf("Unable to update database: %s\n", alpm_strerrorlast());
 *     } else if(result == 1) {
 *         printf("Database already up to date\n");
 *     } else {
 *         printf("Database updated\n");
 *     }
 * }
 * @endcode
 *
 * @ingroup alpm_databases
 * @note After a successful update, the \link alpm_db_get_pkgcache()
 * package cache \endlink will be invalidated
 * @param force if true, then forces the update, otherwise update only in case
 * the database isn't up to date
 * @param db pointer to the package database to update
 * @return 0 on success, -1 on error (pm_errno is set accordingly), 1 if up to
 * to date
 */
int SYMEXPORT alpm_db_update(int force, alpm_db_t *db)
{
    char *syncpath;
    alpm_list_t *i;
    int ret = -1;
    mode_t oldmask;
    alpm_handle_t *handle;
    alpm_siglevel_t level;

    /* Sanity checks */
    ASSERT(db != NULL, return -1);
    handle = db->handle;
    handle->pm_errno = 0;
    ASSERT(db != handle->db_local, RET_ERR(handle, ALPM_ERR_WRONG_ARGS, -1));
    ASSERT(db->servers != NULL, RET_ERR(handle, ALPM_ERR_SERVER_NONE, -1));

    syncpath = get_sync_dir(handle);
    if(!syncpath) {
        return -1;
    }

    /* make sure we have a sane umask */
    oldmask = umask(0022);

    level = alpm_db_get_siglevel(db);

    /* attempt to grab a lock */
    if(_alpm_handle_lock(handle)) {
        free(syncpath);
        umask(oldmask);
        RET_ERR(handle, ALPM_ERR_HANDLE_LOCK, -1);
    }

    for(i = db->servers; i; i = i->next) {
        const char *server = i->data;
        struct dload_payload payload;
        size_t len;
        int sig_ret = 0;

        memset(&payload, 0, sizeof(struct dload_payload));

        /* set hard upper limit of 25MiB */
        payload.max_size = 25 * 1024 * 1024;

        /* print server + filename into a buffer */
        len = strlen(server) + strlen(db->treename) + 5;
        /* TODO fix leak syncpath and umask unset */
        MALLOC(payload.fileurl, len, RET_ERR(handle, ALPM_ERR_MEMORY, -1));
        snprintf(payload.fileurl, len, "%s/%s.db", server, db->treename);
        payload.handle = handle;
        payload.force = force;
        payload.unlink_on_fail = 1;

        ret = _alpm_download(&payload, syncpath, NULL);
        _alpm_dload_payload_reset(&payload);

        if(ret == 0 && (level & ALPM_SIG_DATABASE)) {
            /* an existing sig file is no good at this point */
            char *sigpath = _alpm_sigpath(handle, _alpm_db_path(db));
            if(!sigpath) {
                ret = -1;
                break;
            }
            unlink(sigpath);
            free(sigpath);

            /* if we downloaded a DB, we want the .sig from the same server */
            /* print server + filename into a buffer (leave space for .sig) */
            len = strlen(server) + strlen(db->treename) + 9;
            /* TODO fix leak syncpath and umask unset */
            MALLOC(payload.fileurl, len, RET_ERR(handle, ALPM_ERR_MEMORY, -1));
            snprintf(payload.fileurl, len, "%s/%s.db.sig", server, db->treename);
            payload.handle = handle;
            payload.force = 1;
            payload.errors_ok = (level & ALPM_SIG_DATABASE_OPTIONAL);

            /* set hard upper limit of 16KiB */
            payload.max_size = 16 * 1024;

            sig_ret = _alpm_download(&payload, syncpath, NULL);
            /* errors_ok suppresses error messages, but not the return code */
            sig_ret = payload.errors_ok ? 0 : sig_ret;
            _alpm_dload_payload_reset(&payload);
        }

        if(ret != -1 && sig_ret != -1) {
            break;
        }
    }

    if(ret == 1) {
        /* files match, do nothing */
        handle->pm_errno = 0;
        goto cleanup;
    } else if(ret == -1) {
        /* pm_errno was set by the download code */
        _alpm_log(handle, ALPM_LOG_DEBUG, "failed to sync db: %s\n",
                alpm_strerror(handle->pm_errno));
        goto cleanup;
    }

    /* Cache needs to be rebuilt */
    _alpm_db_free_pkgcache(db);

    /* clear all status flags regarding validity/existence */
    db->status &= ~DB_STATUS_VALID;
    db->status &= ~DB_STATUS_INVALID;
    db->status &= ~DB_STATUS_EXISTS;
    db->status &= ~DB_STATUS_MISSING;

    if(sync_db_validate(db)) {
        /* pm_errno should be set */
        ret = -1;
    }

cleanup:

    if(_alpm_handle_unlock(handle)) {
        _alpm_log(handle, ALPM_LOG_WARNING, _("could not remove lock file %s\n"),
                handle->lockfile);
    }
    free(syncpath);
    umask(oldmask);
    return ret;
}

/* Forward decl so I don't reorganize the whole file right now */
static int sync_db_read(alpm_db_t *db, struct archive *archive,
        struct archive_entry *entry, alpm_pkg_t **likely_pkg);

static alpm_pkg_t *load_pkg_for_entry(alpm_db_t *db, const char *entryname,
        const char **entry_filename, alpm_pkg_t *likely_pkg)
{
    char *pkgname = NULL, *pkgver = NULL;
    unsigned long pkgname_hash;
    alpm_pkg_t *pkg;

    /* get package and db file names */
    if(entry_filename) {
        char *fname = strrchr(entryname, '/');
        if(fname) {
            *entry_filename = fname + 1;
        } else {
            *entry_filename = NULL;
        }
    }
    if(_alpm_splitname(entryname, &pkgname, &pkgver, &pkgname_hash) != 0) {
        _alpm_log(db->handle, ALPM_LOG_ERROR,
                _("invalid name for database entry '%s'\n"), entryname);
        return NULL;
    }

    if(likely_pkg && pkgname_hash == likely_pkg->name_hash
            && strcmp(likely_pkg->name, pkgname) == 0) {
        pkg = likely_pkg;
    } else {
        pkg = _alpm_pkghash_find(db->pkgcache, pkgname);
    }
    if(pkg == NULL) {
        pkg = _alpm_pkg_new();
        if(pkg == NULL) {
            RET_ERR(db->handle, ALPM_ERR_MEMORY, NULL);
        }

        pkg->name = pkgname;
        pkg->version = pkgver;
        pkg->name_hash = pkgname_hash;

        pkg->origin = PKG_FROM_SYNCDB;
        pkg->origin_data.db = db;
        pkg->ops = &default_pkg_ops;
        pkg->handle = db->handle;

        /* add to the collection */
        _alpm_log(db->handle, ALPM_LOG_FUNCTION, "adding '%s' to package cache for db '%s'\n",
                pkg->name, db->treename);
        db->pkgcache = _alpm_pkghash_add(db->pkgcache, pkg);
    } else {
        free(pkgname);
        free(pkgver);
    }

    return pkg;
}

/* This function doesn't work as well as one might think, as size of database
 * entries varies considerably. Adding signatures nearly doubles the size of a
 * single entry; deltas also can make for large variations in size. These
 * current values are heavily influenced by Arch Linux; databases with no
 * deltas and a single signature per package. */
static size_t estimate_package_count(struct stat *st, struct archive *archive)
{
    int per_package;

    switch(archive_compression(archive)) {
        case ARCHIVE_COMPRESSION_NONE:
            per_package = 3015;
            break;
        case ARCHIVE_COMPRESSION_GZIP:
        case ARCHIVE_COMPRESSION_COMPRESS:
            per_package = 464;
            break;
        case ARCHIVE_COMPRESSION_BZIP2:
            per_package = 394;
            break;
        case ARCHIVE_COMPRESSION_LZMA:
        case ARCHIVE_COMPRESSION_XZ:
            per_package = 400;
            break;
#ifdef ARCHIVE_COMPRESSION_UU
        case ARCHIVE_COMPRESSION_UU:
            per_package = 3015 * 4 / 3;
            break;
#endif
        default:
            /* assume it is at least somewhat compressed */
            per_package = 500;
    }
    return (size_t)((st->st_size / per_package) + 1);
}

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);

    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:
    archive_read_finish(archive);
    if(fd >= 0) {
        CLOSE(fd);
    }
    return count;
}

#define READ_NEXT() do { \
    if(_alpm_archive_fgets(archive, &buf) != ARCHIVE_OK) goto error; \
    line = buf.line; \
    _alpm_strip_newline(line); \
} while(0)

#define READ_AND_STORE(f) do { \
    READ_NEXT(); \
    STRDUP(f, line, goto error); \
} while(0)

#define READ_AND_STORE_ALL(f) do { \
    char *linedup; \
    if(_alpm_archive_fgets(archive, &buf) != ARCHIVE_OK) goto error; \
    if(_alpm_strip_newline(buf.line) == 0) break; \
    STRDUP(linedup, buf.line, goto error); \
    f = alpm_list_add(f, linedup); \
} while(1) /* note the while(1) and not (0) */

#define READ_AND_SPLITDEP(f) do { \
    if(_alpm_archive_fgets(archive, &buf) != ARCHIVE_OK) goto error; \
    if(_alpm_strip_newline(buf.line) == 0) break; \
    f = alpm_list_add(f, _alpm_splitdep(line)); \
} while(1) /* note the while(1) and not (0) */

static int sync_db_read(alpm_db_t *db, struct archive *archive,
        struct archive_entry *entry, alpm_pkg_t **likely_pkg)
{
    const char *entryname, *filename;
    alpm_pkg_t *pkg;
    struct archive_read_buffer buf;

    entryname = archive_entry_pathname(entry);
    if(entryname == NULL) {
        _alpm_log(db->handle, ALPM_LOG_DEBUG,
                "invalid archive entry provided to _alpm_sync_db_read, skipping\n");
        return -1;
    }

    _alpm_log(db->handle, ALPM_LOG_FUNCTION, "loading package data from archive entry %s\n",
            entryname);

    memset(&buf, 0, sizeof(buf));
    /* 512K for a line length seems reasonable */
    buf.max_line_size = 512 * 1024;

    pkg = load_pkg_for_entry(db, entryname, &filename, *likely_pkg);

    if(pkg == NULL) {
        _alpm_log(db->handle, ALPM_LOG_DEBUG,
                "entry %s could not be loaded into %s sync database",
                entryname, db->treename);
        return -1;
    }

    if(strcmp(filename, "desc") == 0 || strcmp(filename, "depends") == 0
            || strcmp(filename, "deltas") == 0) {
        int ret;
        while((ret = _alpm_archive_fgets(archive, &buf)) == ARCHIVE_OK) {
            char *line = buf.line;
            if(_alpm_strip_newline(line) == 0) {
                /* length of stripped line was zero */
                continue;
            }

            if(strcmp(line, "%NAME%") == 0) {
                READ_NEXT();
                if(strcmp(line, pkg->name) != 0) {
                    _alpm_log(db->handle, ALPM_LOG_ERROR, _("%s database is inconsistent: name "
                                "mismatch on package %s\n"), db->treename, pkg->name);
                }
            } else if(strcmp(line, "%VERSION%") == 0) {
                READ_NEXT();
                if(strcmp(line, pkg->version) != 0) {
                    _alpm_log(db->handle, ALPM_LOG_ERROR, _("%s database is inconsistent: version "
                                "mismatch on package %s\n"), db->treename, pkg->name);
                }
            } else if(strcmp(line, "%FILENAME%") == 0) {
                READ_AND_STORE(pkg->filename);
            } else if(strcmp(line, "%DESC%") == 0) {
                READ_AND_STORE(pkg->desc);
            } else if(strcmp(line, "%GROUPS%") == 0) {
                READ_AND_STORE_ALL(pkg->groups);
            } else if(strcmp(line, "%URL%") == 0) {
                READ_AND_STORE(pkg->url);
            } else if(strcmp(line, "%LICENSE%") == 0) {
                READ_AND_STORE_ALL(pkg->licenses);
            } else if(strcmp(line, "%ARCH%") == 0) {
                READ_AND_STORE(pkg->arch);
            } else if(strcmp(line, "%BUILDDATE%") == 0) {
                READ_NEXT();
                pkg->builddate = _alpm_parsedate(line);
            } else if(strcmp(line, "%PACKAGER%") == 0) {
                READ_AND_STORE(pkg->packager);
            } else if(strcmp(line, "%CSIZE%") == 0) {
                READ_NEXT();
                pkg->size = _alpm_strtoofft(line);
            } else if(strcmp(line, "%ISIZE%") == 0) {
                READ_NEXT();
                pkg->isize = _alpm_strtoofft(line);
            } else if(strcmp(line, "%MD5SUM%") == 0) {
                READ_AND_STORE(pkg->md5sum);
            } else if(strcmp(line, "%SHA256SUM%") == 0) {
                READ_AND_STORE(pkg->sha256sum);
            } else if(strcmp(line, "%PGPSIG%") == 0) {
                READ_AND_STORE(pkg->base64_sig);
            } else if(strcmp(line, "%REPLACES%") == 0) {
                READ_AND_SPLITDEP(pkg->replaces);
            } else if(strcmp(line, "%DEPENDS%") == 0) {
                READ_AND_SPLITDEP(pkg->depends);
            } else if(strcmp(line, "%OPTDEPENDS%") == 0) {
                READ_AND_STORE_ALL(pkg->optdepends);
            } else if(strcmp(line, "%CONFLICTS%") == 0) {
                READ_AND_SPLITDEP(pkg->conflicts);
            } else if(strcmp(line, "%PROVIDES%") == 0) {
                READ_AND_SPLITDEP(pkg->provides);
            } else if(strcmp(line, "%DELTAS%") == 0) {
                /* Different than the rest because of the _alpm_delta_parse call. */
                while(1) {
                    READ_NEXT();
                    if(strlen(line) == 0) break;
                    pkg->deltas = alpm_list_add(pkg->deltas,
                            _alpm_delta_parse(db->handle, line));
                }
            }
        }
        if(ret != ARCHIVE_EOF) {
            goto error;
        }
        *likely_pkg = pkg;
    } else if(strcmp(filename, "files") == 0) {
        /* currently do nothing with this file */
    } else {
        /* unknown database file */
        _alpm_log(db->handle, ALPM_LOG_DEBUG, "unknown database file: %s\n", filename);
    }

    return 0;

error:
    _alpm_log(db->handle, ALPM_LOG_DEBUG, "error parsing database file: %s\n", filename);
    return -1;
}

struct db_operations sync_db_ops = {
    .validate         = sync_db_validate,
    .populate         = sync_db_populate,
    .unregister       = _alpm_db_unregister,
};

alpm_db_t *_alpm_db_register_sync(alpm_handle_t *handle, const char *treename,
        alpm_siglevel_t level)
{
    alpm_db_t *db;

    _alpm_log(handle, ALPM_LOG_DEBUG, "registering sync database '%s'\n", treename);

#ifndef HAVE_LIBGPGME
    if(level != 0 && level != ALPM_SIG_USE_DEFAULT) {
        RET_ERR(handle, ALPM_ERR_WRONG_ARGS, NULL);
    }
#endif

    db = _alpm_db_new(treename, 0);
    if(db == NULL) {
        RET_ERR(handle, ALPM_ERR_DB_CREATE, NULL);
    }
    db->ops = &sync_db_ops;
    db->handle = handle;
    db->siglevel = level;

    sync_db_validate(db);

    handle->dbs_sync = alpm_list_add(handle->dbs_sync, db);
    return db;
}

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