/*-

 * Copyright (c) 2003-2007 Tim Kientzle

 * 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(S) ``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(S) 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 "archive_platform.h"

__FBSDID("$FreeBSD: head/lib/libarchive/archive_read_disk_set_standard_lookup.c 201109 2009-12-28 03:30:31Z kientzle $");

#ifdef HAVE_SYS_TYPES_H

#include <sys/types.h>

#endif

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

#ifdef HAVE_GRP_H

#include <grp.h>

#endif

#ifdef HAVE_PWD_H

#include <pwd.h>

#endif

#ifdef HAVE_STDLIB_H

#include <stdlib.h>

#endif

#ifdef HAVE_STRING_H

#include <string.h>

#endif

#include "archive.h"

#if defined(_WIN32) && !defined(__CYGWIN__)

int

archive_read_disk_set_standard_lookup(struct archive *a)

{

	archive_set_error(a, -1, "Standard lookups not available on Windows");

	return (ARCHIVE_FATAL);

}

#else /* ! (_WIN32 && !__CYGWIN__) */

#define	name_cache_size 127

static const char * const NO_NAME = "(noname)";

struct name_cache {

	struct archive *archive;

	char   *buff;

	size_t  buff_size;

	int	probes;

	int	hits;

	size_t	size;

	struct {

		id_t id;

		const char *name;

	} cache[name_cache_size];

};

static const char *	lookup_gname(void *, int64_t);

static const char *	lookup_uname(void *, int64_t);

static void	cleanup(void *);

static const char *	lookup_gname_helper(struct name_cache *, id_t gid);

static const char *	lookup_uname_helper(struct name_cache *, id_t uid);

/*

 * Installs functions that use getpwuid()/getgrgid()---along with

 * a simple cache to accelerate such lookups---into the archive_read_disk

 * object.  This is in a separate file because getpwuid()/getgrgid()

 * can pull in a LOT of library code (including NIS/LDAP functions, which

 * pull in DNS resolvers, etc).  This can easily top 500kB, which makes

 * it inappropriate for some space-constrained applications.

 *

 * Applications that are size-sensitive may want to just use the

 * real default functions (defined in archive_read_disk.c) that just

 * use the uid/gid without the lookup.  Or define your own custom functions

 * if you prefer.

 */

int

archive_read_disk_set_standard_lookup(struct archive *a)

{

	struct name_cache *ucache = malloc(sizeof(struct name_cache));

	struct name_cache *gcache = malloc(sizeof(struct name_cache));

	if (ucache == NULL || gcache == NULL) {

		archive_set_error(a, ENOMEM,

		    "Can't allocate uname/gname lookup cache");

		free(ucache);

		free(gcache);

		return (ARCHIVE_FATAL);

	}

	memset(ucache, 0, sizeof(*ucache));

	ucache->archive = a;

	ucache->size = name_cache_size;

	memset(gcache, 0, sizeof(*gcache));

	gcache->archive = a;

	gcache->size = name_cache_size;

	archive_read_disk_set_gname_lookup(a, gcache, lookup_gname, cleanup);

	archive_read_disk_set_uname_lookup(a, ucache, lookup_uname, cleanup);

	return (ARCHIVE_OK);

}

static void

cleanup(void *data)

{

	struct name_cache *cache = (struct name_cache *)data;

	size_t i;

	if (cache != NULL) {

		for (i = 0; i < cache->size; i++) {

			if (cache->cache[i].name != NULL &&

			    cache->cache[i].name != NO_NAME)

				free((void *)(uintptr_t)cache->cache[i].name);

		}

		free(cache->buff);

		free(cache);

	}

}

/*

 * Lookup uid/gid from uname/gname, return NULL if no match.

 */

static const char *

lookup_name(struct name_cache *cache,

    const char * (*lookup_fn)(struct name_cache *, id_t), id_t id)

{

	const char *name;

	int slot;

	cache->probes++;

	slot = id % cache->size;

	if (cache->cache[slot].name != NULL) {

		if (cache->cache[slot].id == id) {

			cache->hits++;

			if (cache->cache[slot].name == NO_NAME)

				return (NULL);

			return (cache->cache[slot].name);

		}

		if (cache->cache[slot].name != NO_NAME)

			free((void *)(uintptr_t)cache->cache[slot].name);

		cache->cache[slot].name = NULL;

	}

	name = (lookup_fn)(cache, id);

	if (name == NULL) {

		/* Cache and return the negative response. */

		cache->cache[slot].name = NO_NAME;

		cache->cache[slot].id = id;

		return (NULL);

	}

	cache->cache[slot].name = name;

	cache->cache[slot].id = id;

	return (cache->cache[slot].name);

}

static const char *

lookup_uname(void *data, int64_t uid)

{

	struct name_cache *uname_cache = (struct name_cache *)data;

	return (lookup_name(uname_cache,

		    &lookup_uname_helper, (id_t)uid));

}

#if HAVE_GETPWUID_R

static const char *

lookup_uname_helper(struct name_cache *cache, id_t id)

{

	struct passwd	pwent, *result;

	char * nbuff;

	size_t nbuff_size;

	int r;

	if (cache->buff_size == 0) {

		cache->buff_size = 256;

		cache->buff = malloc(cache->buff_size);

	}

	if (cache->buff == NULL)

		return (NULL);

	for (;;) {

		result = &pwent; /* Old getpwuid_r ignores last arg. */

		r = getpwuid_r((uid_t)id, &pwent,

			       cache->buff, cache->buff_size, &result);

		if (r == 0)

			break;

		if (r != ERANGE)

			break;

		/* ERANGE means our buffer was too small, but POSIX

		 * doesn't tell us how big the buffer should be, so

		 * we just double it and try again.  Because the buffer

		 * is kept around in the cache object, we shouldn't

		 * have to do this very often. */

		nbuff_size = cache->buff_size * 2;

		nbuff = realloc(cache->buff, nbuff_size);

		if (nbuff == NULL)

			break;

		cache->buff = nbuff;

		cache->buff_size = nbuff_size;

	}

	if (r != 0) {

		archive_set_error(cache->archive, errno,

		    "Can't lookup user for id %d", (int)id);

		return (NULL);

	}

	if (result == NULL)

		return (NULL);

	return strdup(result->pw_name);

}

#else

static const char *

lookup_uname_helper(struct name_cache *cache, id_t id)

{

	struct passwd	*result;

	(void)cache; /* UNUSED */

	result = getpwuid((uid_t)id);

	if (result == NULL)

		return (NULL);

	return strdup(result->pw_name);

}

#endif

static const char *

lookup_gname(void *data, int64_t gid)

{

	struct name_cache *gname_cache = (struct name_cache *)data;

	return (lookup_name(gname_cache,

		    &lookup_gname_helper, (id_t)gid));

}

#if HAVE_GETGRGID_R

static const char *

lookup_gname_helper(struct name_cache *cache, id_t id)

{

	struct group	grent, *result;

	char * nbuff;

	size_t nbuff_size;

	int r;

	if (cache->buff_size == 0) {

		cache->buff_size = 256;

		cache->buff = malloc(cache->buff_size);

	}

	if (cache->buff == NULL)

		return (NULL);

	for (;;) {

		result = &grent; /* Old getgrgid_r ignores last arg. */

		r = getgrgid_r((gid_t)id, &grent,

			       cache->buff, cache->buff_size, &result);

		if (r == 0)

			break;

		if (r != ERANGE)

			break;

		/* ERANGE means our buffer was too small, but POSIX

		 * doesn't tell us how big the buffer should be, so

		 * we just double it and try again. */

		nbuff_size = cache->buff_size * 2;

		nbuff = realloc(cache->buff, nbuff_size);

		if (nbuff == NULL)

			break;

		cache->buff = nbuff;

		cache->buff_size = nbuff_size;

	}

	if (r != 0) {

		archive_set_error(cache->archive, errno,

		    "Can't lookup group for id %d", (int)id);

		return (NULL);

	}

	if (result == NULL)

		return (NULL);

	return strdup(result->gr_name);

}

#else

static const char *

lookup_gname_helper(struct name_cache *cache, id_t id)

{

	struct group	*result;

	(void)cache; /* UNUSED */

	result = getgrgid((gid_t)id);

	if (result == NULL)

		return (NULL);

	return strdup(result->gr_name);

}

#endif

#endif /* ! (_WIN32 && !__CYGWIN__) */