far-rcv/far-xattr.c

/*
 * Copyright (C) 2012, 2013 STRATO AG.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

/*
 * Handling of extended attributes aka xattr or extattr is located in this
 * file. It is different for Linux, SunOS and all the other operating systems.
 * Refer to <http://en.wikipedia.org/wiki/Extended_file_attributes>.
 * This current implementation supports Linux and SunOS.
 * These functions are used internally in the far-rcv library.
 */

#include <sys/types.h>
#include <errno.h>

#if defined (__LINUX__)
#include <attr/xattr.h>
#else /* !defined (__LINUX__) */
#include <stdio.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <assert.h>
#endif /* !defined (__LINUX__) */

#include "far-xattr.h"


int far_rcv_lsetxattr(const char *path, const char *name, const void *value,
		      size_t size)
{
#if defined (__LINUX__)
	if (lsetxattr(path, name, value, size, 0) < 0)
		return -errno;
	else
		return 0;
#else /* !defined (__LINUX__) */
	int fd = -1;
	int ret = 0;

	fd = attropen(path, name, O_TRUNC | O_WRONLY | O_CREAT);
	if (fd < 0) {
		ret = -errno;
		fprintf(stderr,
			"ERROR: attropen(%s, %s) for writing failed. %s\n",
			path, name, strerror(-ret));
		goto out;
	}
	while (size) {
		ret = write(fd, value, size);
		if (ret == -1 && errno == EINTR) {
			continue;
		} else if (ret == -1) {
			ret = -errno;
			fprintf(stderr,
				"ERROR: write() xattr %s in %s failed. %s\n",
				name, path, strerror(-ret));
			goto out;
		}
		assert(ret > 0);
		size -= ret;
		value += ret;
		ret = 0;
	}
out:
	if (fd != -1)
		close(fd);
	return ret;
#endif /* !defined (__LINUX__) */
}

int far_rcv_lremovexattr(const char *path, const char *name)
{
#if defined (__LINUX__)
	if (lremovexattr(path, name) < 0)
		return -errno;
	else
		return 0;
#else /* !defined (__LINUX__) */
	int attrdirfd;
	int ret = 0;

	attrdirfd = attropen(path, ".", O_RDONLY);
	if (attrdirfd < 0) {
		ret = -errno;
		fprintf(stderr,
			"ERROR: attropen(%s, \".\") failed. %s\n", path,
			strerror(-ret));
		goto out;
	}

	if (unlinkat(attrdirfd, name, 0) < 0) {
		ret = -errno;
		fprintf(stderr,
			"ERROR: unlinkat(%s) failed in %s. %s\n", name, path,
			strerror(-ret));
		goto out;
	}

out:
	if (attrdirfd != -1)
		close(attrdirfd);
	return ret;
#endif /* !defined (__LINUX__) */
}