exfat/libexfat/mount.c - android_bootable_recovery - Gitiles

 /*
 	mount.c (22.10.09)
 	exFAT file system implementation library.

 	Copyright (C) 2010-2012  Andrew Nayenko

 	This program is free software: you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
 	the Free Software Foundation, either version 3 of the License, or
 	(at your option) any later version.

 	This program is distributed in the hope that it will be useful,
 	but WITHOUT ANY WARRANTY; without even the implied warranty of
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 	GNU General Public License for more details.

 	You should have received a copy of the GNU General Public License
 	along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

 #include "exfat.h"
 #include <string.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sys/types.h>

 static uint64_t rootdir_size(const struct exfat* ef)
 {
 	uint64_t clusters = 0;
 	cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);

 	while (!CLUSTER_INVALID(rootdir_cluster))
 	{
 		clusters++;
 		/* root directory cannot be contiguous because there is no flag
 		   to indicate this */
 		rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
 	}
 	return clusters * CLUSTER_SIZE(*ef->sb);
 }

 static const char* get_option(const char* options, const char* option_name)
 {
 	const char* p;
 	size_t length = strlen(option_name);

 	for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
 		if ((p == options || p[-1] == ',') && p[length] == '=')
 			return p + length + 1;
 	return NULL;
 }

 static int get_int_option(const char* options, const char* option_name,
 		int base, int default_value)
 {
 	const char* p = get_option(options, option_name);

 	if (p == NULL)
 		return default_value;
 	return strtol(p, NULL, base);
 }

 static bool match_option(const char* options, const char* option_name)
 {
 	const char* p;
 	size_t length = strlen(option_name);

 	for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
 		if ((p == options || p[-1] == ',') &&
 				(p[length] == ',' || p[length] == '\0'))
 			return true;
 	return false;
 }

 static void parse_options(struct exfat* ef, const char* options)
 {
 	int sys_umask = umask(0);
 	int opt_umask;

 	umask(sys_umask); /* restore umask */
 	opt_umask = get_int_option(options, "umask", 8, sys_umask);
 	ef->dmask = get_int_option(options, "dmask", 8, opt_umask) & 0777;
 	ef->fmask = get_int_option(options, "fmask", 8, opt_umask) & 0777;

 	ef->uid = get_int_option(options, "uid", 10, geteuid());
 	ef->gid = get_int_option(options, "gid", 10, getegid());

 	ef->noatime = match_option(options, "noatime");
 }

 static int verify_vbr_checksum(struct exfat_dev* dev, void* sector,
 		off64_t sector_size)
 {
 	uint32_t vbr_checksum;
 	int i;

 	exfat_pread(dev, sector, sector_size, 0);
 	vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
 	for (i = 1; i < 11; i++)
 	{
 		exfat_pread(dev, sector, sector_size, i * sector_size);
 		vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
 				vbr_checksum);
 	}
 	exfat_pread(dev, sector, sector_size, i * sector_size);
 	for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
 		if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
 		{
 			exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
 					le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
 			return 1;
 		}
 	return 0;
 }

 static int commit_super_block(const struct exfat* ef)
 {
 	exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0);
 	return exfat_fsync(ef->dev);
 }

 static int prepare_super_block(const struct exfat* ef)
 {
 	if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
 		exfat_warn("volume was not unmounted cleanly");

 	if (ef->ro)
 		return 0;

 	ef->sb->volume_state = cpu_to_le16(
 			le16_to_cpu(ef->sb->volume_state) | EXFAT_STATE_MOUNTED);
 	return commit_super_block(ef);
 }

 int exfat_mount(struct exfat* ef, const char* spec, const char* options)
 {
 	int rc;
 	enum exfat_mode mode;

 	exfat_tzset();
 	memset(ef, 0, sizeof(struct exfat));

 	parse_options(ef, options);

 	if (match_option(options, "ro"))
 		mode = EXFAT_MODE_RO;
 	else if (match_option(options, "ro_fallback"))
 		mode = EXFAT_MODE_ANY;
 	else
 		mode = EXFAT_MODE_RW;
 	ef->dev = exfat_open(spec, mode);
 	if (ef->dev == NULL)
 		return -EIO;
 	if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
 	{
 		if (mode == EXFAT_MODE_ANY)
 			ef->ro = -1;
 		else
 			ef->ro = 1;
 	}

 	ef->sb = malloc(sizeof(struct exfat_super_block));
 	if (ef->sb == NULL)
 	{
 		exfat_close(ef->dev);
 		exfat_error("failed to allocate memory for the super block");
 		return -ENOMEM;
 	}
 	memset(ef->sb, 0, sizeof(struct exfat_super_block));

 	exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0);
 	if (memcmp(ef->sb->oem_name, "EXFAT   ", 8) != 0)
 	{
 		exfat_close(ef->dev);
 		free(ef->sb);
 		exfat_error("exFAT file system is not found");
 		return -EIO;
 	}
 	if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
 	{
 		exfat_close(ef->dev);
 		exfat_error("unsupported exFAT version: %hhu.%hhu",
 				ef->sb->version.major, ef->sb->version.minor);
 		free(ef->sb);
 		return -EIO;
 	}
 	if (ef->sb->fat_count != 1)
 	{
 		exfat_close(ef->dev);
 		free(ef->sb);
 		exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
 		return -EIO;
 	}
 	/* officially exFAT supports cluster size up to 32 MB */
 	if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
 	{
 		exfat_close(ef->dev);
 		free(ef->sb);
 		exfat_error("too big cluster size: 2^%d",
 				(int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
 		return -EIO;
 	}

 	ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
 	if (ef->zero_cluster == NULL)
 	{
 		exfat_close(ef->dev);
 		free(ef->sb);
 		exfat_error("failed to allocate zero sector");
 		return -ENOMEM;
 	}
 	/* use zero_cluster as a temporary buffer for VBR checksum verification */
 	if (verify_vbr_checksum(ef->dev, ef->zero_cluster,
 			SECTOR_SIZE(*ef->sb)) != 0)
 	{
 		free(ef->zero_cluster);
 		exfat_close(ef->dev);
 		free(ef->sb);
 		return -EIO;
 	}
 	memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));

 	ef->root = malloc(sizeof(struct exfat_node));
 	if (ef->root == NULL)
 	{
 		free(ef->zero_cluster);
 		exfat_close(ef->dev);
 		free(ef->sb);
 		exfat_error("failed to allocate root node");
 		return -ENOMEM;
 	}
 	memset(ef->root, 0, sizeof(struct exfat_node));
 	ef->root->flags = EXFAT_ATTRIB_DIR;
 	ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
 	ef->root->fptr_cluster = ef->root->start_cluster;
 	ef->root->name[0] = cpu_to_le16('\0');
 	ef->root->size = rootdir_size(ef);
 	/* exFAT does not have time attributes for the root directory */
 	ef->root->mtime = 0;
 	ef->root->atime = 0;
 	/* always keep at least 1 reference to the root node */
 	exfat_get_node(ef->root);

 	rc = exfat_cache_directory(ef, ef->root);
 	if (rc != 0)
 		goto error;
 	if (ef->upcase == NULL)
 	{
 		exfat_error("upcase table is not found");
 		goto error;
 	}
 	if (ef->cmap.chunk == NULL)
 	{
 		exfat_error("clusters bitmap is not found");
 		goto error;
 	}

 	if (prepare_super_block(ef) != 0)
 		goto error;

 	return 0;

 error:
 	exfat_put_node(ef, ef->root);
 	exfat_reset_cache(ef);
 	free(ef->root);
 	free(ef->zero_cluster);
 	exfat_close(ef->dev);
 	free(ef->sb);
 	return -EIO;
 }

 static void finalize_super_block(struct exfat* ef)
 {
 	if (ef->ro)
 		return;

 	ef->sb->volume_state = cpu_to_le16(
 			le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);

 	/* Some implementations set the percentage of allocated space to 0xff
 	   on FS creation and never update it. In this case leave it as is. */
 	if (ef->sb->allocated_percent != 0xff)
 	{
 		uint32_t free, total;

 		free = exfat_count_free_clusters(ef);
 		total = le32_to_cpu(ef->sb->cluster_count);
 		ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
 	}

 	commit_super_block(ef);
 }

 void exfat_unmount(struct exfat* ef)
 {
 	exfat_put_node(ef, ef->root);
 	exfat_reset_cache(ef);
 	free(ef->root);
 	ef->root = NULL;
 	finalize_super_block(ef);
 	exfat_close(ef->dev);	/* close descriptor immediately after fsync */
 	ef->dev = NULL;
 	free(ef->zero_cluster);
 	ef->zero_cluster = NULL;
 	free(ef->cmap.chunk);
 	ef->cmap.chunk = NULL;
 	free(ef->sb);
 	ef->sb = NULL;
 	free(ef->upcase);
 	ef->upcase = NULL;
 	ef->upcase_chars = 0;
 }
	/*
	mount.c (22.10.09)
	exFAT file system implementation library.

	Copyright (C) 2010-2012 Andrew Nayenko

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "exfat.h"
	#include <string.h>
	#include <stdlib.h>
	#include <errno.h>
	#include <unistd.h>
	#include <sys/types.h>

	static uint64_t rootdir_size(const struct exfat* ef)
	{
	uint64_t clusters = 0;
	cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);

	while (!CLUSTER_INVALID(rootdir_cluster))
	{
	clusters++;
	/* root directory cannot be contiguous because there is no flag
	to indicate this */
	rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
	}
	return clusters * CLUSTER_SIZE(*ef->sb);
	}

	static const char* get_option(const char* options, const char* option_name)
	{
	const char* p;
	size_t length = strlen(option_name);

	for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
	if ((p == options \|\| p[-1] == ',') && p[length] == '=')
	return p + length + 1;
	return NULL;
	}

	static int get_int_option(const char* options, const char* option_name,
	int base, int default_value)
	{
	const char* p = get_option(options, option_name);

	if (p == NULL)
	return default_value;
	return strtol(p, NULL, base);
	}

	static bool match_option(const char* options, const char* option_name)
	{
	const char* p;
	size_t length = strlen(option_name);

	for (p = strstr(options, option_name); p; p = strstr(p + 1, option_name))
	if ((p == options \|\| p[-1] == ',') &&
	(p[length] == ',' \|\| p[length] == '\0'))
	return true;
	return false;
	}

	static void parse_options(struct exfat* ef, const char* options)
	{
	int sys_umask = umask(0);
	int opt_umask;

	umask(sys_umask); /* restore umask */
	opt_umask = get_int_option(options, "umask", 8, sys_umask);
	ef->dmask = get_int_option(options, "dmask", 8, opt_umask) & 0777;
	ef->fmask = get_int_option(options, "fmask", 8, opt_umask) & 0777;

	ef->uid = get_int_option(options, "uid", 10, geteuid());
	ef->gid = get_int_option(options, "gid", 10, getegid());

	ef->noatime = match_option(options, "noatime");
	}

	static int verify_vbr_checksum(struct exfat_dev* dev, void* sector,
	off64_t sector_size)
	{
	uint32_t vbr_checksum;
	int i;

	exfat_pread(dev, sector, sector_size, 0);
	vbr_checksum = exfat_vbr_start_checksum(sector, sector_size);
	for (i = 1; i < 11; i++)
	{
	exfat_pread(dev, sector, sector_size, i * sector_size);
	vbr_checksum = exfat_vbr_add_checksum(sector, sector_size,
	vbr_checksum);
	}
	exfat_pread(dev, sector, sector_size, i * sector_size);
	for (i = 0; i < sector_size / sizeof(vbr_checksum); i++)
	if (le32_to_cpu(((const le32_t*) sector)[i]) != vbr_checksum)
	{
	exfat_error("invalid VBR checksum 0x%x (expected 0x%x)",
	le32_to_cpu(((const le32_t*) sector)[i]), vbr_checksum);
	return 1;
	}
	return 0;
	}

	static int commit_super_block(const struct exfat* ef)
	{
	exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0);
	return exfat_fsync(ef->dev);
	}

	static int prepare_super_block(const struct exfat* ef)
	{
	if (le16_to_cpu(ef->sb->volume_state) & EXFAT_STATE_MOUNTED)
	exfat_warn("volume was not unmounted cleanly");

	if (ef->ro)
	return 0;

	ef->sb->volume_state = cpu_to_le16(
	le16_to_cpu(ef->sb->volume_state) \| EXFAT_STATE_MOUNTED);
	return commit_super_block(ef);
	}

	int exfat_mount(struct exfat* ef, const char* spec, const char* options)
	{
	int rc;
	enum exfat_mode mode;

	exfat_tzset();
	memset(ef, 0, sizeof(struct exfat));

	parse_options(ef, options);

	if (match_option(options, "ro"))
	mode = EXFAT_MODE_RO;
	else if (match_option(options, "ro_fallback"))
	mode = EXFAT_MODE_ANY;
	else
	mode = EXFAT_MODE_RW;
	ef->dev = exfat_open(spec, mode);
	if (ef->dev == NULL)
	return -EIO;
	if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
	{
	if (mode == EXFAT_MODE_ANY)
	ef->ro = -1;
	else
	ef->ro = 1;
	}

	ef->sb = malloc(sizeof(struct exfat_super_block));
	if (ef->sb == NULL)
	{
	exfat_close(ef->dev);
	exfat_error("failed to allocate memory for the super block");
	return -ENOMEM;
	}
	memset(ef->sb, 0, sizeof(struct exfat_super_block));

	exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0);
	if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
	{
	exfat_close(ef->dev);
	free(ef->sb);
	exfat_error("exFAT file system is not found");
	return -EIO;
	}
	if (ef->sb->version.major != 1 \|\| ef->sb->version.minor != 0)
	{
	exfat_close(ef->dev);
	exfat_error("unsupported exFAT version: %hhu.%hhu",
	ef->sb->version.major, ef->sb->version.minor);
	free(ef->sb);
	return -EIO;
	}
	if (ef->sb->fat_count != 1)
	{
	exfat_close(ef->dev);
	free(ef->sb);
	exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
	return -EIO;
	}
	/* officially exFAT supports cluster size up to 32 MB */
	if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
	{
	exfat_close(ef->dev);
	free(ef->sb);
	exfat_error("too big cluster size: 2^%d",
	(int) ef->sb->sector_bits + (int) ef->sb->spc_bits);
	return -EIO;
	}

	ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
	if (ef->zero_cluster == NULL)
	{
	exfat_close(ef->dev);
	free(ef->sb);
	exfat_error("failed to allocate zero sector");
	return -ENOMEM;
	}
	/* use zero_cluster as a temporary buffer for VBR checksum verification */
	if (verify_vbr_checksum(ef->dev, ef->zero_cluster,
	SECTOR_SIZE(*ef->sb)) != 0)
	{
	free(ef->zero_cluster);
	exfat_close(ef->dev);
	free(ef->sb);
	return -EIO;
	}
	memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));

	ef->root = malloc(sizeof(struct exfat_node));
	if (ef->root == NULL)
	{
	free(ef->zero_cluster);
	exfat_close(ef->dev);
	free(ef->sb);
	exfat_error("failed to allocate root node");
	return -ENOMEM;
	}
	memset(ef->root, 0, sizeof(struct exfat_node));
	ef->root->flags = EXFAT_ATTRIB_DIR;
	ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
	ef->root->fptr_cluster = ef->root->start_cluster;
	ef->root->name[0] = cpu_to_le16('\0');
	ef->root->size = rootdir_size(ef);
	/* exFAT does not have time attributes for the root directory */
	ef->root->mtime = 0;
	ef->root->atime = 0;
	/* always keep at least 1 reference to the root node */
	exfat_get_node(ef->root);

	rc = exfat_cache_directory(ef, ef->root);
	if (rc != 0)
	goto error;
	if (ef->upcase == NULL)
	{
	exfat_error("upcase table is not found");
	goto error;
	}
	if (ef->cmap.chunk == NULL)
	{
	exfat_error("clusters bitmap is not found");
	goto error;
	}

	if (prepare_super_block(ef) != 0)
	goto error;

	return 0;

	error:
	exfat_put_node(ef, ef->root);
	exfat_reset_cache(ef);
	free(ef->root);
	free(ef->zero_cluster);
	exfat_close(ef->dev);
	free(ef->sb);
	return -EIO;
	}

	static void finalize_super_block(struct exfat* ef)
	{
	if (ef->ro)
	return;

	ef->sb->volume_state = cpu_to_le16(
	le16_to_cpu(ef->sb->volume_state) & ~EXFAT_STATE_MOUNTED);

	/* Some implementations set the percentage of allocated space to 0xff
	on FS creation and never update it. In this case leave it as is. */
	if (ef->sb->allocated_percent != 0xff)
	{
	uint32_t free, total;

	free = exfat_count_free_clusters(ef);
	total = le32_to_cpu(ef->sb->cluster_count);
	ef->sb->allocated_percent = ((total - free) * 100 + total / 2) / total;
	}

	commit_super_block(ef);
	}

	void exfat_unmount(struct exfat* ef)
	{
	exfat_put_node(ef, ef->root);
	exfat_reset_cache(ef);
	free(ef->root);
	ef->root = NULL;
	finalize_super_block(ef);
	exfat_close(ef->dev); /* close descriptor immediately after fsync */
	ef->dev = NULL;
	free(ef->zero_cluster);
	ef->zero_cluster = NULL;
	free(ef->cmap.chunk);
	ef->cmap.chunk = NULL;
	free(ef->sb);
	ef->sb = NULL;
	free(ef->upcase);
	ef->upcase = NULL;
	ef->upcase_chars = 0;
	}