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Diffstat (limited to '')
| -rw-r--r-- | exfat/libexfat/mount.c | 338 |
1 files changed, 338 insertions, 0 deletions
diff --git a/exfat/libexfat/mount.c b/exfat/libexfat/mount.c new file mode 100644 index 000000000..928c561dc --- /dev/null +++ b/exfat/libexfat/mount.c @@ -0,0 +1,338 @@ +/* + mount.c (22.10.09) + exFAT file system implementation library. + + Free exFAT implementation. + Copyright (C) 2010-2013 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 2 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, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. +*/ + +#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; + + if (exfat_pread(dev, sector, sector_size, 0) < 0) + { + exfat_error("failed to read boot sector"); + return 1; + } + vbr_checksum = exfat_vbr_start_checksum(sector, sector_size); + for (i = 1; i < 11; i++) + { + if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0) + { + exfat_error("failed to read VBR sector"); + return 1; + } + vbr_checksum = exfat_vbr_add_checksum(sector, sector_size, + vbr_checksum); + } + if (exfat_pread(dev, sector, sector_size, i * sector_size) < 0) + { + exfat_error("failed to read VBR checksum sector"); + return 1; + } + 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) +{ + if (exfat_pwrite(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0) + { + exfat_error("failed to write super block"); + return 1; + } + 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)); + + if (exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0) + { + exfat_close(ef->dev); + free(ef->sb); + exfat_error("failed to read boot sector"); + return -EIO; + } + 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; +} |