/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
 * apply_xattr.c
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#include "mkfs.h"

#ifdef HAVE_SYS_XATTR_H
static char *get_full_path(const char *prefix, tree_node_t *node)
{
	char *path = NULL, *new = NULL;
	size_t path_len, prefix_len;
	int ret;

	path = fstree_get_path(node);
	if (path == NULL)
		goto fail;

	ret = canonicalize_name(path);
	assert(ret == 0);

	path_len = strlen(path);
	prefix_len = strlen(prefix);

	while (prefix_len > 0 && prefix[prefix_len - 1] == '/')
		--prefix_len;

	if (prefix_len > 0) {
		new = realloc(path, path_len + prefix_len + 2);
		if (new == NULL)
			goto fail;

		path = new;

		memmove(path + prefix_len + 1, path, path_len + 1);
		memcpy(path, prefix, prefix_len);
		path[prefix_len] = '/';
	}

	return path;
fail:
	perror("getting full path for xattr scan");
	free(path);
	return NULL;
}

static int xattr_from_path(sqfs_xattr_writer_t *xwr, const char *path)
{
	char *key, *value = NULL, *buffer = NULL;
	ssize_t buflen, vallen, keylen;
	int ret;

	buflen = llistxattr(path, NULL, 0);
	if (buflen < 0) {
		fprintf(stderr, "llistxattr %s: %s", path, strerror(errno));
		return -1;
	}

	if (buflen == 0)
		return 0;

	buffer = malloc(buflen);
	if (buffer == NULL) {
		perror("xattr name buffer");
		return -1;
	}

	buflen = llistxattr(path, buffer, buflen);
	if (buflen == -1) {
		fprintf(stderr, "llistxattr %s: %s", path, strerror(errno));
		goto fail;
	}

	key = buffer;
	while (buflen > 0) {
		vallen = lgetxattr(path, key, NULL, 0);
		if (vallen == -1) {
			fprintf(stderr, "lgetxattr %s: %s",
				path, strerror(errno));
			goto fail;
		}

		if (vallen > 0) {
			value = calloc(1, vallen);
			if (value == NULL) {
				perror("allocating xattr value buffer");
				goto fail;
			}

			vallen = lgetxattr(path, key, value, vallen);
			if (vallen == -1) {
				fprintf(stderr, "lgetxattr %s: %s\n",
					path, strerror(errno));
				goto fail;
			}

			ret = sqfs_xattr_writer_add_kv(xwr, key, value, vallen);
			if (ret) {
				sqfs_perror(path,
					    "storing xattr key-value pairs",
					    ret);
				goto fail;
			}

			free(value);
			value = NULL;
		}

		keylen = strlen(key) + 1;
		buflen -= keylen;
		key += keylen;
	}

	free(buffer);
	return 0;
fail:
	free(value);
	free(buffer);
	return -1;
}
#endif

static int apply_dfs(const options_t *opt, sqfs_xattr_writer_t *xwr,
		     void *sehnd, void *maphnd, tree_node_t *n)
{
	char *path = NULL;
	int ret;

	ret = sqfs_xattr_writer_begin(xwr, 0);
	if (ret) {
		sqfs_perror(n->name, "recoding xattr key-value pairs\n", ret);
		return -1;
	}

#ifdef HAVE_SYS_XATTR_H
	if (opt->infile == NULL && opt->scan_xattr) {
		path = get_full_path(opt->packdir, n);
		if (path == NULL)
			return -1;

		ret = xattr_from_path(xwr, path);
		free(path);
		path = NULL;
		if (ret)
			return -1;
	}
#endif

	if (sehnd != NULL || maphnd != NULL) {
		path = fstree_get_path(n);
		if (path == NULL) {
			perror("reconstructing absolute path");
			return -1;
		}
	}

	if (maphnd != NULL && xattr_apply_map_file(path, maphnd, xwr) != 0)
		goto fail;

	if (sehnd != NULL && selinux_relable_node(sehnd, xwr, n, path) != 0)
		goto fail;

	free(path);

	ret = sqfs_xattr_writer_end(xwr, &n->xattr_idx);
	if (ret) {
		sqfs_perror(n->name, "completing xattr key-value pairs", ret);
		return -1;
	}

	if (S_ISDIR(n->mode)) {
		for (n = n->data.children; n != NULL; n = n->next) {
			if (apply_dfs(opt, xwr, sehnd, maphnd, n))
				return -1;
		}
	}

	return 0;
fail:
	free(path);
	return -1;
}

int apply_xattrs(fstree_t *fs, const options_t *opt, void *sehnd,
		 void *maphnd, sqfs_xattr_writer_t *xwr)
{
	if (xwr == NULL)
		return 0;

	if (sehnd == NULL && maphnd == NULL &&
	    !(opt->infile == NULL && opt->scan_xattr)) {
		return 0;
	}

	return apply_dfs(opt, xwr, sehnd, maphnd, fs->root);
}