package_remove.c

/*-
 * Copyright (c) 2009-2015 Juan Romero Pardines.
 * All rights reserved.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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 <sys/stat.h>
 
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
 
#include "xbps_api_impl.h"
 
static bool
check_remove_pkg_files(struct xbps_handle *xhp,
        xbps_array_t obsoletes, const char *pkgver, uid_t euid)
{
        struct stat st;
        bool fail = false;
 
        if (euid == 0)
                return false;
 
        for (unsigned int i = 0; i < xbps_array_count(obsoletes); i++) {
                const char *file = NULL;
                xbps_array_get_cstring_nocopy(obsoletes, i, &file);
                /*
                 * Check if effective user ID owns the file; this is
                 * enough to ensure the user has write permissions
                 * on the directory.
                 */
                if (lstat(file, &st) == 0 && euid == st.st_uid) {
                        /* success */
                        continue;
                }
                if (errno != ENOENT) {
                        /*
                         * only bail out if something else than ENOENT
                         * is returned.
                         */
                        int rv = errno;
                        if (rv == 0) {
                                /* lstat succeeds but euid != uid */
                                rv = EPERM;
                        }
                        fail = true;
                        xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FILE_FAIL,
                                rv, pkgver,
                                "%s: cannot remove `%s': %s",
                                pkgver, file, strerror(rv));
                }
                errno = 0;
        }
        return fail;
}
 
static int
remove_pkg_files(struct xbps_handle *xhp,
                 xbps_array_t obsoletes,
                 const char *pkgver)
{
        int rv = 0;
 
        for (unsigned int i = 0; i < xbps_array_count(obsoletes); i++) {
                const char *file = NULL;
                xbps_array_get_cstring_nocopy(obsoletes, i, &file);
                /*
                 * Remove the object if possible.
                 */
                if (remove(file) == -1) {
                        xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FILE_FAIL,
                            errno, pkgver,
                            "%s: failed to remove `%s': %s", pkgver,
                            file, strerror(errno));
                } else {
                        /* success */
                        xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FILE,
                            0, pkgver, "Removed `%s'", file);
                }
        }
 
        return rv;
}
 
int HIDDEN
xbps_remove_pkg(struct xbps_handle *xhp, const char *pkgver, bool update)
{
        xbps_dictionary_t pkgd = NULL, obsd = NULL;
        xbps_array_t obsoletes = NULL;
        char pkgname[XBPS_NAME_SIZE], metafile[PATH_MAX];
        int rv = 0;
        pkg_state_t state = 0;
        uid_t euid;
 
        assert(xhp);
        assert(pkgver);
 
        if (!xbps_pkg_name(pkgname, sizeof(pkgname), pkgver)) {
                abort();
        }
 
        euid = geteuid();
 
        if ((pkgd = xbps_pkgdb_get_pkg(xhp, pkgname)) == NULL) {
                rv = errno;
                xbps_dbg_printf("[remove] cannot find %s in pkgdb: %s\n",
                    pkgver, strerror(rv));
                goto out;
        }
        if ((rv = xbps_pkg_state_dictionary(pkgd, &state)) != 0) {
                xbps_dbg_printf("[remove] cannot find %s in pkgdb: %s\n",
                    pkgver, strerror(rv));
                goto out;
        }
        xbps_dbg_printf("attempting to remove %s state %d\n", pkgver, state);
 
        if (!update)
                xbps_set_cb_state(xhp, XBPS_STATE_REMOVE, 0, pkgver, NULL);
 
        if (chdir(xhp->rootdir) == -1) {
                rv = errno;
                xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FAIL,
                    rv, pkgver,
                   "%s: [remove] failed to chdir to rootdir `%s': %s",
                    pkgver, xhp->rootdir, strerror(rv));
                goto out;
        }
 
        /* If package was "half-removed", remove it fully. */
        if (state == XBPS_PKG_STATE_HALF_REMOVED)
                goto purge;
 
        /* show remove-msg if exists */
        if ((rv = xbps_cb_message(xhp, pkgd, "remove-msg")) != 0)
                goto out;
 
        /* unregister alternatives */
        if (update)
                xbps_dictionary_set_bool(pkgd, "alternatives-update", true);
 
        if ((rv = xbps_alternatives_unregister(xhp, pkgd)) != 0)
                goto out;
 
        /*
         * If updating a package, we just need to execute the current
         * pre-remove action target and we are done. Its files will be
         * overwritten later in unpack phase.
         */
        if (update) {
                return 0;
        }
 
        if (xbps_dictionary_get_dict(xhp->transd, "obsolete_files", &obsd))
                obsoletes = xbps_dictionary_get(obsd, pkgname);
 
        if (xbps_array_count(obsoletes) > 0) {
                /*
                 * Do the removal in 2 phases:
                 *      1- check if user has enough perms to remove all entries
                 *      2- perform removal
                 */
                if (check_remove_pkg_files(xhp, obsoletes, pkgver, euid)) {
                        rv = EPERM;
                        goto out;
                }
                /* Remove links */
                if ((rv = remove_pkg_files(xhp, obsoletes, pkgver)) != 0)
                        goto out;
        }
 
        /*
         * Set package state to "half-removed".
         */
        rv = xbps_set_pkg_state_dictionary(pkgd,
             XBPS_PKG_STATE_HALF_REMOVED);
        if (rv != 0) {
                xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FAIL,
                    rv, pkgver,
                    "%s: [remove] failed to set state to half-removed: %s",
                    pkgver, strerror(rv));
                goto out;
        }
        /* XXX: setting the state and then removing the package seems useless. */
 
purge:
        /*
         * Remove package metadata plist.
         */
        snprintf(metafile, sizeof(metafile), "%s/.%s-files.plist", xhp->metadir, pkgname);
        if (remove(metafile) == -1) {
                if (errno != ENOENT) {
                        xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FAIL,
                            rv, pkgver,
                            "%s: failed to remove metadata file: %s",
                            pkgver, strerror(errno));
                }
        }
        /*
         * Unregister package from pkgdb.
         */
        xbps_dbg_printf("[remove] unregister %s returned %d\n", pkgver, rv);
        xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_DONE, 0, pkgver, NULL);
        xbps_dictionary_remove(xhp->pkgdb, pkgname);
out:
        if (rv != 0) {
                xbps_set_cb_state(xhp, XBPS_STATE_REMOVE_FAIL, rv, pkgver,
                    "%s: failed to remove package: %s", pkgver, strerror(rv));
        }
 
        return rv;
}