transaction_files.c

/*-
 * Copyright (c) 2019 Juan Romero Pardines.
 * Copyright (c) 2019 Duncan Overbruck <mail@duncano.de>.
 * 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 <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
 
#include <archive.h>
#include <archive_entry.h>
 
#include "xbps_api_impl.h"
#include "uthash.h"
 
enum type {
        TYPE_LINK = 1,
        TYPE_DIR,
        TYPE_FILE,
        TYPE_CONFFILE,
};
 
struct item {
        char *file;
        size_t len;
        struct {
                const char *pkgname;
                const char *pkgver;
                char *sha256;
                const char *target;
                uint64_t size;
                enum type type;
                /* index is the index of the package update/install/removal in the transaction
                 * and is used to decide which package should remove the given file or dir */
                unsigned int index;
                bool preserve;
                bool update;
                bool removepkg;
        } old, new;
        bool deleted;
        UT_hash_handle hh;
};
 
/* hash table to look up files by path */
static struct item *hashtab = NULL;
 
/* list of files to be sorted using qsort */
static struct item **items = NULL;
static size_t itemsidx = 0;
static size_t itemssz = 0;
 
static struct item *
lookupItem(const char *file)
{
        struct item *item = NULL;
 
        assert(file);
 
        HASH_FIND_STR(hashtab, file, item);
        return item;
}
 
static struct item *
addItem(const char *file)
{
        struct item *item = calloc(1, sizeof (struct item));
        if (item == NULL)
                return NULL;
 
        assert(file);
        assert(item);
 
        if (itemsidx+1 >= itemssz) {
                itemssz = itemssz ? itemssz*2 : 64;
                items = realloc(items, itemssz*sizeof (struct item *));
                if (items == NULL) {
                        free(item);
                        return NULL;
                }
        }
        items[itemsidx++] = item;
 
        if ((item->file = xbps_xasprintf(".%s", file)) == NULL) {
                free(item);
                return NULL;
        }
        item->len = strlen(item->file);
 
        /*
         * File paths are stored relative, but looked up absolute.
         * Skip the leading . (dot) and substract it from the length.
         */
        HASH_ADD_KEYPTR(hh, hashtab, item->file+1, item->len-1, item);
 
        return item;
}
 
static const char *
typestr(enum type typ)
{
        switch (typ) {
        case TYPE_LINK:     return "symlink";
        case TYPE_DIR:      return "directory";
        case TYPE_FILE:     return "file";
        case TYPE_CONFFILE: return "configuration file";
        default:            return NULL;
        }
}
 
static bool
match_preserved_file(struct xbps_handle *xhp, const char *file)
{
        if (xhp->preserved_files == NULL)
                return false;
 
        assert(file && *file == '.');
        return xbps_match_string_in_array(xhp->preserved_files, file+1);
}
 
static bool
can_delete_directory(const char *file, size_t len, size_t max)
{
        struct item *item;
        size_t rmcount = 0, fcount = 0;
        DIR *dp;
 
        dp = opendir(file);
        if (dp == NULL) {
                if (errno == ENOENT) {
                        return true;
                } else {
                        xbps_dbg_printf("[files] %s: %s: %s\n",
                            __func__, file, strerror(errno));
                        return false;
                }
        }
 
        /*
         * 1. Check if there is tracked directory content,
         *    which can't be deleted.
         * 2. Count deletable directory content.
         */
        for (size_t i = 0; i < max; i++) {
                item = items[i];
                if (strncmp(item->file, file, len) == 0) {
                        if (!item->deleted) {
                                closedir(dp);
                                return false;
                        }
                        rmcount++;
                }
        }
 
        /*
         * Check if directory contains more files than we can
         * delete.
         */
        while (readdir(dp) != 0)
                fcount++;
 
        /* ignore '.' and '..' */
        fcount -= 2;
 
        if (fcount <= rmcount) {
                xbps_dbg_printf("[files] only removed %zu out of %zu files: %s\n",
                    rmcount, fcount, file);
        }
        closedir(dp);
 
        return fcount <= rmcount;
}
 
static int
collect_obsoletes(struct xbps_handle *xhp)
{
        /* These are symlinks in Void and must not be removed */
        const char *basesymlinks[] = {
                "/bin",
                "/sbin",
                "/usr/sbin",
                "/lib",
                "/lib32",
                "/lib64",
                "/usr/lib32",
                "/usr/lib64",
                "/var/run",
        };
        xbps_dictionary_t obsd;
        struct item *item;
        int rv = 0;
 
        if (xhp->transd == NULL)
                return ENOTSUP;
 
        if (!xbps_dictionary_get_dict(xhp->transd, "obsolete_files", &obsd))
                return ENOENT;
 
        /*
         * Iterate over all files, longest paths first,
         * to check if directory contents of removed
         * directories can be deleted.
         *
         * - Check if a file is obsolete
         * - Check if obsolete file can be deleted.
         * - Check if directory needs and can be deleted.
         */
        for (size_t i = 0; i < itemsidx; i++) {
                xbps_array_t a;
                const char *pkgname;
                bool alloc = false, found = false;
 
                item = items[i];
 
                if (match_preserved_file(xhp, item->file)) {
                        xbps_dbg_printf("[obsoletes] %s: file exists on disk"
                            " and must be preserved: %s\n", item->old.pkgver, item->file);
                        continue;
                }
 
                if (item->new.type == 0) {
                        /*
                         * File was removed and is not provided by any
                         * new package.
                         * Probably obsolete.
                         */
                        if (item->old.preserve && item->old.update) {
                                xbps_dbg_printf("[files] %s: skipping `preserve` %s: %s\n",
                                    item->old.pkgver, typestr(item->old.type), item->file);
                                continue;
                        }
                } else if (item->new.type == TYPE_CONFFILE) {
                        /*
                         * Ignore conf files.
                         */
                        continue;
                } else if (item->old.type == 0) {
                        /* XXX: add this new behaviour? */
#if 0
                        /*
                         * Check if new file (untracked until now) exists.
                         */
                        if (access(item->file, F_OK) == 0) {
                                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                                    EEXIST, item->new.pkgver,
                                    "%s: file `%s' already exists.",
                                    item->new.pkgver, item->file);
                                rv = EEXIST;
                                break;
                        }
#endif
                        continue;
                } else if (item->old.type == TYPE_DIR &&
                    item->new.type != TYPE_DIR && item->new.type != 0) {
                        /*
                         * Directory replaced by a file or symlink.
                         * We MUST be able to delete the directory.
                         */
                        xbps_dbg_printf("[files] %s: directory changed to %s: %s\n",
                            item->new.pkgver, typestr(item->new.type), item->file);
                        if (!can_delete_directory(item->file, item->len, i)) {
                                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                                    ENOTEMPTY, item->old.pkgver,
                                    "%s: directory `%s' can not be deleted.",
                                    item->old.pkgver, item->file);
                                return ENOTEMPTY;
                        }
                } else if (item->new.type != item->old.type) {
                        /*
                         * File type changed, we have to delete it.
                         */
                } else {
                        continue;
                }
 
                /*
                 * Make sure to not remove any symlink of root directory.
                 */
                for (uint8_t x = 0; x < __arraycount(basesymlinks); x++) {
                        if (strcmp(item->file+1, basesymlinks[x]) == 0) {
                                found = true;
                                break;
                        }
                }
                if (found)
                        continue;
 
                /*
                 * Skip unexisting files and keep files with hash mismatch.
                 */
                if (item->old.sha256 != NULL) {
                        rv = xbps_file_sha256_check(item->file, item->old.sha256);
                        switch (rv) {
                        case 0:
                                /* hash matches, we can safely delete and/or overwrite it */
                                break;
                        case ENOENT:
                                /* mark unexisting files as deleted and ignore ENOENT */
                                rv = 0;
                                item->deleted = true;
                                continue;
                        case ERANGE:
                                /* hash mismatch don't delete it */
                                rv = 0;
                                /*
                                 * If the file is removed by uninstalling the package,
                                 * no new package provides it and its not force removed,
                                 * keep the file.
                                 */
                                if (item->old.removepkg && !item->new.pkgname &&
                                    (xhp->flags & XBPS_FLAG_FORCE_REMOVE_FILES) != 0) {
                                        xbps_dbg_printf("[obsoletes] %s: SHA256 mismatch,"
                                            " force remove %s: %s\n",
                                                item->old.pkgname, typestr(item->old.type),
                                            item->file+1);
                                        break;
                                }
                                xbps_dbg_printf("[obsoletes] %s: SHA256 mismatch,"
                                    " skipping remove %s: %s\n",
                                    item->old.pkgname, typestr(item->old.type),
                                    item->file+1);
                                continue;
                        default:
                                break;
                        }
                }
 
                /*
                 * On package removal without force, keep symlinks if target changed.
                 */
                if (item->old.pkgname && item->old.removepkg &&
                    item->old.type == TYPE_LINK && !item->new.pkgname &&
                    (xhp->flags & XBPS_FLAG_FORCE_REMOVE_FILES) == 0) {
                        char path[PATH_MAX], *lnk;
                        const char *file = item->file+1;
                        if (strcmp(xhp->rootdir, "/") != 0) {
                                snprintf(path, sizeof(path), "%s%s",
                                    xhp->rootdir, item->file+1);
                                file = path;
                        }
                        lnk = xbps_symlink_target(xhp, file, item->old.target);
                        if (lnk == NULL) {
                                xbps_dbg_printf("[obsoletes] %s "
                                    "symlink_target: %s\n", item->file+1, strerror(errno));
                                continue;
                        }
                        if (strcmp(lnk, item->old.target) != 0) {
                                xbps_dbg_printf("[obsoletes] %s: skipping modified"
                                    " symlink (stored `%s' current `%s'): %s\n",
                                    item->old.pkgname, item->old.target, lnk, item->file+1);
                                free(lnk);
                                continue;
                        }
                        free(lnk);
                }
 
                /*
                 * Choose which package removes the obsolete files,
                 * based which packages is installed/unpacked first.
                 * This is necessary to not delete files
                 * after it was installed by another package.
                 */
                if (item->old.pkgname && item->new.pkgname) {
                        pkgname = item->old.index > item->new.index ?
                                item->new.pkgname : item->old.pkgname;
                } else if (item->old.pkgname) {
                        pkgname = item->old.pkgname;
                } else {
                        pkgname = item->new.pkgname;
                }
                assert(pkgname);
 
                xbps_dbg_printf("[obsoletes] %s: removes %s: %s\n",
                    pkgname, typestr(item->old.type), item->file+1);
 
                /*
                 * Mark file as being deleted, this is used when
                 * checking if a directory can be deleted.
                 */
                item->deleted = true;
 
                /*
                 * Add file to the packages `obsolete_files` dict
                 */
                if ((a = xbps_dictionary_get(obsd, pkgname)) == NULL) {
                        if (!(a = xbps_array_create()) ||
                                !(xbps_dictionary_set(obsd, pkgname, a)))
                                return ENOMEM;
                        alloc = true;
                }
                if (!xbps_array_add_cstring(a, item->file)) {
                        if (alloc)
                                xbps_object_release(a);
                        return ENOMEM;
                }
                if (alloc)
                        xbps_object_release(a);
        }
 
        return rv;
}
 
static int
collect_file(struct xbps_handle *xhp, const char *file, size_t size,
                const char *pkgname, const char *pkgver, unsigned int idx,
                const char *sha256, enum type type, bool update, bool removepkg,
                bool preserve, bool removefile, const char *target)
{
        struct item *item;
 
        assert(file);
 
        if ((item = lookupItem(file)) == NULL) {
                item = addItem(file);
                if (item == NULL)
                        return ENOMEM;
                item->deleted = false;
                goto add;
        }
 
        if (removefile) {
                if (item->old.type == 0) {
                        /*
                         * File wasn't removed before.
                         */
                } else if (type == TYPE_DIR && item->old.type == TYPE_DIR) {
                        /*
                         * Multiple packages removing the same directory.
                         * Record the last package to remove this directory.
                         */
                        if (idx < item->old.index || item->old.preserve)
                                return 0;
                        item->old.pkgname = pkgname;
                        item->old.pkgver = pkgver;
                        item->old.index = idx;
                        item->old.preserve = preserve;
                        item->old.update = update;
                        item->old.removepkg = removepkg;
                        return 0;
                } else {
                        /*
                         * Multiple packages removing the same file.
                         * Shouldn't happen, but its not fatal.
                         */
                        xbps_dbg_printf("[files] %s: file already removed"
                            " by package `%s': %s\n", pkgver, item->old.pkgver, file);
 
                        /*
                         * Check if `preserve` is violated.
                         */
                        if (item->old.preserve && !preserve) {
                                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                                    EPERM, item->old.pkgver,
                                    "%s: preserved file `%s' removed by %s.",
                                    item->old.pkgver, file, pkgver);
                                return EPERM;
                        } else if (preserve && !item->old.preserve) {
                                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                                    EPERM, pkgver,
                                    "%s: preserved file `%s' removed by %s.",
                                    pkgver, file, item->old.pkgver);
                                return EPERM;
                        }
                        return 0;
                }
                goto add;
        } else {
                /*
                 * Multiple packages creating the same directory.
                 */
                if (item->new.type == 0) {
                        /*
                         * File wasn't created before.
                         */
                } else if (type == TYPE_DIR && item->new.type == TYPE_DIR) {
                        /*
                         * Multiple packages creating the same directory.
                         */
                        return 0;
                } else {
                        /*
                         * Multiple packages creating the same file.
                         * This should never happen in a transaction.
                         */
                        xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                            EEXIST, pkgver,
                            "%s: file `%s' already installed by package %s.",
                            pkgver, file, item->new.pkgver);
                        if (xhp->flags & XBPS_FLAG_IGNORE_FILE_CONFLICTS)
                                return 0;
 
                        return EEXIST;
                }
                goto add;
        }
 
        return 0;
add:
        if (removefile) {
                item->old.pkgname = pkgname;
                item->old.pkgver = pkgver;
                item->old.type = type;
                item->old.size = size;
                item->old.index = idx;
                item->old.preserve = preserve;
                item->old.update = update;
                item->old.removepkg = removepkg;
                item->old.target = target;
                if (sha256)
                        item->old.sha256 = strdup(sha256);
        } else {
                item->new.pkgname = pkgname;
                item->new.pkgver = pkgver;
                item->new.type = type;
                item->new.size = size;
                item->new.index = idx;
                item->new.preserve = preserve;
                item->new.update = update;
                item->new.removepkg = removepkg;
                item->new.target = target;
        }
        if (item->old.type && item->new.type) {
                /*
                 * The file was removed by one package
                 * and installed by another package.
                 */
                if (strcmp(item->new.pkgname, item->old.pkgname) != 0) {
                        if (removefile) {
                                xbps_dbg_printf("[files] %s: %s moved to"
                                    " package `%s': %s\n", pkgver, typestr(item->old.type),
                                    item->new.pkgver, file);
                        } else {
                                xbps_dbg_printf("[files] %s: %s moved from"
                                    " package `%s': %s\n", pkgver, typestr(item->new.type),
                                    item->old.pkgver, file);
                        }
                }
        }
 
        return 0;
}
 
static int
collect_files(struct xbps_handle *xhp, xbps_dictionary_t d,
                        const char *pkgname, const char *pkgver, unsigned int idx,
                        bool update, bool removepkg, bool preserve, bool removefile)
{
        xbps_array_t a;
        xbps_dictionary_t filed;
        uint64_t size;
        unsigned int i;
        int rv = 0;
        const char *file, *sha256 = NULL;
        bool error = false;
 
        if ((a = xbps_dictionary_get(d, "files"))) {
                for (i = 0; i < xbps_array_count(a); i++) {
                        filed = xbps_array_get(a, i);
                        xbps_dictionary_get_cstring_nocopy(filed, "file", &file);
                        if (removefile)
                                xbps_dictionary_get_cstring_nocopy(filed, "sha256", &sha256);
                        size = 0;
                        xbps_dictionary_get_uint64(filed, "size", &size);
                        rv = collect_file(xhp, file, size, pkgname, pkgver, idx, sha256,
                            TYPE_FILE, update, removepkg, preserve, removefile, NULL);
                        if (rv == EEXIST) {
                                error = true;
                                continue;
                        } else if (rv != 0) {
                                goto out;
                        }
                }
        }
        if ((a = xbps_dictionary_get(d, "conf_files"))) {
                for (i = 0; i < xbps_array_count(a); i++) {
                        filed = xbps_array_get(a, i);
                        xbps_dictionary_get_cstring_nocopy(filed, "file", &file);
                        size = 0;
                        xbps_dictionary_get_uint64(filed, "size", &size);
                        if (removefile)
                                xbps_dictionary_get_cstring_nocopy(filed, "sha256", &sha256);
#if 0
                        /* XXX: how to handle conf_file size */
                        if (removefile && stat(file, &st) != -1 && size != (uint64_t)st.st_size)
                                size = 0;
#endif
                        rv = collect_file(xhp, file, size, pkgname, pkgver, idx, sha256,
                            TYPE_CONFFILE, update, removepkg, preserve, removefile, NULL);
                        if (rv == EEXIST) {
                                error = true;
                                continue;
                        } else if (rv != 0) {
                                goto out;
                        }
                }
        }
        if ((a = xbps_dictionary_get(d, "links"))) {
                for (i = 0; i < xbps_array_count(a); i++) {
                        const char *target = NULL;
                        filed = xbps_array_get(a, i);
                        xbps_dictionary_get_cstring_nocopy(filed, "file", &file);
                        xbps_dictionary_get_cstring_nocopy(filed, "target", &target);
                        assert(target);
                        rv = collect_file(xhp, file, 0, pkgname, pkgver, idx, NULL,
                            TYPE_LINK, update, removepkg, preserve, removefile, target);
                        if (rv == EEXIST) {
                                error = true;
                                continue;
                        } else if (rv != 0) {
                                goto out;
                        }
                }
        }
        if ((a = xbps_dictionary_get(d, "dirs"))) {
                for (i = 0; i < xbps_array_count(a); i++) {
                        filed = xbps_array_get(a, i);
                        xbps_dictionary_get_cstring_nocopy(filed, "file", &file);
                        rv = collect_file(xhp, file, 0, pkgname, pkgver, idx, NULL,
                            TYPE_DIR, update, removepkg, preserve, removefile, NULL);
                        if (rv == EEXIST) {
                                error = true;
                                continue;
                        } else if (rv != 0) {
                                goto out;
                        }
                }
        }
 
out:
        if (error)
                rv = EEXIST;
 
        return rv;
}
 
static int
collect_binpkg_files(struct xbps_handle *xhp, xbps_dictionary_t pkg_repod,
                unsigned int idx, bool update)
{
        xbps_dictionary_t filesd;
        struct archive *ar = NULL;
        struct archive_entry *entry;
        struct stat st;
        const char *pkgver, *pkgname;
        char *bpkg;
        /* size_t entry_size; */
        int rv = 0, pkg_fd = -1;
 
        xbps_dictionary_get_cstring_nocopy(pkg_repod, "pkgver", &pkgver);
        assert(pkgver);
        xbps_dictionary_get_cstring_nocopy(pkg_repod, "pkgname", &pkgname);
        assert(pkgname);
 
        bpkg = xbps_repository_pkg_path(xhp, pkg_repod);
        if (bpkg == NULL) {
                rv = errno;
                goto out;
        }
 
        if ((ar = archive_read_new()) == NULL) {
                rv = errno;
                goto out;
        }
 
        /*
         * Enable support for tar format and gzip/bzip2/lzma compression methods.
         */
        archive_read_support_filter_gzip(ar);
        archive_read_support_filter_bzip2(ar);
        archive_read_support_filter_xz(ar);
        archive_read_support_filter_lz4(ar);
        archive_read_support_filter_zstd(ar);
        archive_read_support_format_tar(ar);
 
        pkg_fd = open(bpkg, O_RDONLY|O_CLOEXEC);
        if (pkg_fd == -1) {
                rv = errno;
                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                    rv, pkgver,
                    "%s: failed to open binary package `%s': %s",
                    pkgver, bpkg, strerror(rv));
                goto out;
        }
        if (fstat(pkg_fd, &st) == -1) {
                rv = errno;
                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                    rv, pkgver,
                    "%s: failed to fstat binary package `%s': %s",
                    pkgver, bpkg, strerror(rv));
                goto out;
        }
        if (archive_read_open_fd(ar, pkg_fd, st.st_blksize) == ARCHIVE_FATAL) {
                rv = archive_errno(ar);
                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL,
                    rv, pkgver,
                    "%s: failed to read binary package `%s': %s",
                    pkgver, bpkg, strerror(rv));
                goto out;
        }
 
        for (uint8_t i = 0; i < 4; i++) {
                const char *entry_pname;
                int ar_rv = archive_read_next_header(ar, &entry);
                if (ar_rv == ARCHIVE_EOF || ar_rv == ARCHIVE_FATAL)
                        break;
                else if (ar_rv == ARCHIVE_RETRY)
                        continue;
 
                entry_pname = archive_entry_pathname(entry);
                if ((strcmp("./files.plist", entry_pname)) == 0) {
                        filesd = xbps_archive_get_dictionary(ar, entry);
                        if (filesd == NULL) {
                                rv = EINVAL;
                                goto out;
                        }
                        rv = collect_files(xhp, filesd, pkgname, pkgver, idx,
                            update, false, false, false);
                        xbps_object_release(filesd);
                        goto out;
                }
                archive_read_data_skip(ar);
        }
 
out:
        if (pkg_fd != -1)
                close(pkg_fd);
        if (ar != NULL)
                archive_read_free(ar);
        free(bpkg);
        return rv;
}
 
static int
pathcmp(const void *l1, const void *l2)
{
        const struct item *a = *(const struct item * const*)l1;
        const struct item *b = *(const struct item * const*)l2;
        return (a->len < b->len) - (b->len < a->len);
}
 
static void
cleanup(void)
{
        struct item *item, *itmp;
 
        HASH_ITER(hh, hashtab, item, itmp) {
                HASH_DEL(hashtab, item);
                free(item->file);
                free(item->old.sha256);
                free(item->new.sha256);
                free(item);
        }
        free(items);
}
 
/*
 * xbps_transaction_files:
 *
 * - read files from each installed package in the transaction
 * - read files from each binary package in the transaction
 *
 * - Find file conflicts between packages before starting the transaction
 *
 * - Schedule the removal of files
 *   - unlink files before extracting the package if the file type changed,
 *     a symlink becomes a directory or a directory becomes a regular file
 *     or symlink.
 *   - directories replaced with other file types are checked to be empty
 *     to avoid ENOTEMPTY while unpacking packages.
 *   - the last package removing a file out of a directory
 *     will try to remove that directory to avoid ENOTEMPTY
 *   - the removal of obsolete files and directory is sorted by
 *     path length so that directory content is removed before
 *     removing the directory.
 */
int HIDDEN
xbps_transaction_files(struct xbps_handle *xhp, xbps_object_iterator_t iter)
{
        xbps_dictionary_t pkgd, filesd;
        xbps_object_t obj;
        xbps_trans_type_t ttype;
        const char *pkgver, *pkgname;
        int rv = 0;
        unsigned int idx = 0;
 
        assert(xhp);
        assert(iter);
 
        while ((obj = xbps_object_iterator_next(iter)) != NULL) {
                bool update = false;
 
                /* increment the index of the given package package in the transaction */
                idx++;
 
                /* ignore pkgs in hold mode or in unpacked state */
                ttype = xbps_transaction_pkg_type(obj);
                if (ttype == XBPS_TRANS_HOLD || ttype == XBPS_TRANS_CONFIGURE) {
                        continue;
                }
 
                if (!xbps_dictionary_get_cstring_nocopy(obj, "pkgver", &pkgver)) {
                        return EINVAL;
                }
                if (!xbps_dictionary_get_cstring_nocopy(obj, "pkgname", &pkgname)) {
                        return EINVAL;
                }
 
                update = (ttype == XBPS_TRANS_UPDATE);
 
                if (ttype == XBPS_TRANS_INSTALL || ttype == XBPS_TRANS_REINSTALL || ttype == XBPS_TRANS_UPDATE) {
                        xbps_set_cb_state(xhp, XBPS_STATE_FILES, 0, pkgver,
                            "%s: collecting files...", pkgver);
                        rv = collect_binpkg_files(xhp, obj, idx, update);
                        if (rv != 0)
                                goto out;
                }
 
                /*
                 * Always just try to get the package from the pkgdb:
                 * update and remove always have a previous package,
                 * `hold` and `configure` are skipped.
                 * And finally the reason to do is, `install` could be
                 * a reinstallation, in which case the files list could
                 * different between old and new "install".
                 */
                pkgd = xbps_pkgdb_get_pkg(xhp, pkgname);
                if (pkgd) {
                        const char *oldpkgver;
                        bool preserve = false;
                        bool removepkg = (ttype == XBPS_TRANS_REMOVE);
 
                        xbps_dictionary_get_cstring_nocopy(pkgd, "pkgver", &oldpkgver);
                        if (!xbps_dictionary_get_bool(obj, "preserve", &preserve))
                                preserve = false;
 
                        filesd = xbps_pkgdb_get_pkg_files(xhp, pkgname);
                        if (filesd == NULL) {
                                continue;
                        }
 
                        assert(oldpkgver);
                        xbps_set_cb_state(xhp, XBPS_STATE_FILES, 0, oldpkgver,
                            "%s: collecting files...", oldpkgver);
                        rv = collect_files(xhp, filesd, pkgname, pkgver, idx,
                            update, removepkg, preserve, true);
                        if (rv != 0)
                                goto out;
                }
        }
        xbps_object_iterator_reset(iter);
 
        /*
         * Sort items by path length, to make it easier to find files in
         * directories.
         */
        qsort(items, itemsidx, sizeof (struct item *), pathcmp);
 
        if (chdir(xhp->rootdir) == -1) {
                rv = errno;
                xbps_set_cb_state(xhp, XBPS_STATE_FILES_FAIL, rv, xhp->rootdir,
                    "failed to chdir to rootdir `%s': %s",
                    xhp->rootdir, strerror(errno));
        }
 
out:
        if (rv != 0)
                return rv;
 
        rv = collect_obsoletes(xhp);
        cleanup();
        return rv;
}