libarchive/archive_read_disk_set_standard_lookup.c - third_party/libarchive - Git at Google

 /*-
  * 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 *, gid_t);
 static const char *	lookup_uname(void *, uid_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 resolveers, 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, uid_t uid)
 {
 	struct name_cache *uname_cache = (struct name_cache *)data;
 	return (lookup_name(uname_cache,
 		    &lookup_uname_helper, (id_t)uid));
 }

 static const char *
 lookup_uname_helper(struct name_cache *cache, id_t id)
 {
 	struct passwd	pwent, *result;
 	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. */
 		cache->buff_size *= 2;
 		cache->buff = realloc(cache->buff, cache->buff_size);
 		if (cache->buff == NULL)
 			break;
 	}
 	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);
 }

 static const char *
 lookup_gname(void *data, gid_t gid)
 {
 	struct name_cache *gname_cache = (struct name_cache *)data;
 	return (lookup_name(gname_cache,
 		    &lookup_gname_helper, (id_t)gid));
 }

 static const char *
 lookup_gname_helper(struct name_cache *cache, id_t id)
 {
 	struct group	grent, *result;
 	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. */
 		cache->buff_size *= 2;
 		cache->buff = realloc(cache->buff, cache->buff_size);
 		if (cache->buff == NULL)
 			break;
 	}
 	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);
 }
 #endif /* ! (_WIN32 && !__CYGWIN__) */
	/*-
	* 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 *, gid_t);
	static const char * lookup_uname(void *, uid_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 resolveers, 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, uid_t uid)
	{
	struct name_cache uname_cache = (struct name_cache )data;
	return (lookup_name(uname_cache,
	&lookup_uname_helper, (id_t)uid));
	}

	static const char *
	lookup_uname_helper(struct name_cache *cache, id_t id)
	{
	struct passwd pwent, *result;
	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. */
	cache->buff_size *= 2;
	cache->buff = realloc(cache->buff, cache->buff_size);
	if (cache->buff == NULL)
	break;
	}
	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);
	}

	static const char *
	lookup_gname(void *data, gid_t gid)
	{
	struct name_cache gname_cache = (struct name_cache )data;
	return (lookup_name(gname_cache,
	&lookup_gname_helper, (id_t)gid));
	}

	static const char *
	lookup_gname_helper(struct name_cache *cache, id_t id)
	{
	struct group grent, *result;
	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. */
	cache->buff_size *= 2;
	cache->buff = realloc(cache->buff, cache->buff_size);
	if (cache->buff == NULL)
	break;
	}
	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);
	}
	#endif /* ! (_WIN32 && !__CYGWIN__) */