/*
- * io.c
- * exFAT file system implementation library.
- *
- * Created by Andrew Nayenko on 02.09.09.
- * This software is distributed under the GNU General Public License
- * version 3 or any later.
- */
+ io.c (02.09.09)
+ exFAT file system implementation library.
+
+ Free exFAT implementation.
+ Copyright (C) 2010-2017 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 <inttypes.h>
#include <sys/types.h>
-#include <sys/uio.h>
-#define __USE_UNIX98 /* for pread() in Linux */
+#include <sys/stat.h>
+#include <fcntl.h>
#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#if defined(__APPLE__)
+#include <sys/disk.h>
+#elif defined(__OpenBSD__)
+#include <sys/param.h>
+#include <sys/disklabel.h>
+#include <sys/dkio.h>
+#include <sys/ioctl.h>
+#endif
+#include <sys/mount.h>
-#if _FILE_OFFSET_BITS != 64
- #error You should define _FILE_OFFSET_BITS=64
+struct exfat_dev
+{
+ int fd;
+ enum exfat_mode mode;
+ off_t size; /* in bytes */
+};
+
+static bool is_open(int fd)
+{
+ return fcntl(fd, F_GETFD) != -1;
+}
+
+static int open_ro(const char* spec)
+{
+ return open(spec, O_RDONLY);
+}
+
+static int open_rw(const char* spec)
+{
+ int fd = open(spec, O_RDWR);
+#ifdef __linux__
+ int ro = 0;
+
+ /*
+ This ioctl is needed because after "blockdev --setro" kernel still
+ allows to open the device in read-write mode but fails writes.
+ */
+ if (fd != -1 && ioctl(fd, BLKROGET, &ro) == 0 && ro)
+ {
+ close(fd);
+ errno = EROFS;
+ return -1;
+ }
#endif
+ return fd;
+}
+
+struct exfat_dev* exfat_open(const char* spec, enum exfat_mode mode)
+{
+ struct exfat_dev* dev;
+ struct stat stbuf;
+
+ /* The system allocates file descriptors sequentially. If we have been
+ started with stdin (0), stdout (1) or stderr (2) closed, the system
+ will give us descriptor 0, 1 or 2 later when we open block device,
+ FUSE communication pipe, etc. As a result, functions using stdin,
+ stdout or stderr will actually work with a different thing and can
+ corrupt it. Protect descriptors 0, 1 and 2 from such misuse. */
+ while (!is_open(STDIN_FILENO)
+ || !is_open(STDOUT_FILENO)
+ || !is_open(STDERR_FILENO))
+ {
+ /* we don't need those descriptors, let them leak */
+ if (open("/dev/null", O_RDWR) == -1)
+ {
+ exfat_error("failed to open /dev/null");
+ return NULL;
+ }
+ }
+
+ dev = malloc(sizeof(struct exfat_dev));
+ if (dev == NULL)
+ {
+ exfat_error("failed to allocate memory for device structure");
+ return NULL;
+ }
+
+ switch (mode)
+ {
+ case EXFAT_MODE_RO:
+ dev->fd = open_ro(spec);
+ if (dev->fd == -1)
+ {
+ free(dev);
+ exfat_error("failed to open '%s' in read-only mode: %s", spec,
+ strerror(errno));
+ return NULL;
+ }
+ dev->mode = EXFAT_MODE_RO;
+ break;
+ case EXFAT_MODE_RW:
+ dev->fd = open_rw(spec);
+ if (dev->fd == -1)
+ {
+ free(dev);
+ exfat_error("failed to open '%s' in read-write mode: %s", spec,
+ strerror(errno));
+ return NULL;
+ }
+ dev->mode = EXFAT_MODE_RW;
+ break;
+ case EXFAT_MODE_ANY:
+ dev->fd = open_rw(spec);
+ if (dev->fd != -1)
+ {
+ dev->mode = EXFAT_MODE_RW;
+ break;
+ }
+ dev->fd = open_ro(spec);
+ if (dev->fd != -1)
+ {
+ dev->mode = EXFAT_MODE_RO;
+ exfat_warn("'%s' is write-protected, mounting read-only", spec);
+ break;
+ }
+ free(dev);
+ exfat_error("failed to open '%s': %s", spec, strerror(errno));
+ return NULL;
+ }
+
+ if (fstat(dev->fd, &stbuf) != 0)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to fstat '%s'", spec);
+ return NULL;
+ }
+ if (!S_ISBLK(stbuf.st_mode) &&
+ !S_ISCHR(stbuf.st_mode) &&
+ !S_ISREG(stbuf.st_mode))
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("'%s' is neither a device, nor a regular file", spec);
+ return NULL;
+ }
+
+#if defined(__APPLE__)
+ if (!S_ISREG(stbuf.st_mode))
+ {
+ uint32_t block_size = 0;
+ uint64_t blocks = 0;
+
+ if (ioctl(dev->fd, DKIOCGETBLOCKSIZE, &block_size) != 0)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to get block size");
+ return NULL;
+ }
+ if (ioctl(dev->fd, DKIOCGETBLOCKCOUNT, &blocks) != 0)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to get blocks count");
+ return NULL;
+ }
+ dev->size = blocks * block_size;
+ }
+ else
+#elif defined(__OpenBSD__)
+ if (!S_ISREG(stbuf.st_mode))
+ {
+ struct disklabel lab;
+ struct partition* pp;
+ char* partition;
+
+ if (ioctl(dev->fd, DIOCGDINFO, &lab) == -1)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to get disklabel");
+ return NULL;
+ }
+
+ /* Don't need to check that partition letter is valid as we won't get
+ this far otherwise. */
+ partition = strchr(spec, '\0') - 1;
+ pp = &(lab.d_partitions[*partition - 'a']);
+ dev->size = DL_GETPSIZE(pp) * lab.d_secsize;
+
+ if (pp->p_fstype != FS_NTFS)
+ exfat_warn("partition type is not 0x07 (NTFS/exFAT); "
+ "you can fix this with fdisk(8)");
+ }
+ else
+#endif
+ {
+ /* works for Linux, FreeBSD, Solaris */
+ dev->size = exfat_seek(dev, 0, SEEK_END);
+ if (dev->size <= 0)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to get size of '%s'", spec);
+ return NULL;
+ }
+ if (exfat_seek(dev, 0, SEEK_SET) == -1)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to seek to the beginning of '%s'", spec);
+ return NULL;
+ }
+ }
-#define MIN(a, b) ((a) < (b) ? (a) : (b))
+ return dev;
+}
+
+int exfat_close(struct exfat_dev* dev)
+{
+ int rc = 0;
+
+ if (close(dev->fd) != 0)
+ {
+ exfat_error("failed to close device: %s", strerror(errno));
+ rc = -EIO;
+ }
+ free(dev);
+ return rc;
+}
+
+int exfat_fsync(struct exfat_dev* dev)
+{
+ int rc = 0;
+
+ if (fsync(dev->fd) != 0)
+ {
+ exfat_error("fsync failed: %s", strerror(errno));
+ rc = -EIO;
+ }
+ return rc;
+}
+
+enum exfat_mode exfat_get_mode(const struct exfat_dev* dev)
+{
+ return dev->mode;
+}
+
+off_t exfat_get_size(const struct exfat_dev* dev)
+{
+ return dev->size;
+}
+
+off_t exfat_seek(struct exfat_dev* dev, off_t offset, int whence)
+{
+ return lseek(dev->fd, offset, whence);
+}
+
+ssize_t exfat_read(struct exfat_dev* dev, void* buffer, size_t size)
+{
+ return read(dev->fd, buffer, size);
+}
+
+ssize_t exfat_write(struct exfat_dev* dev, const void* buffer, size_t size)
+{
+ return write(dev->fd, buffer, size);
+}
+
+ssize_t exfat_pread(struct exfat_dev* dev, void* buffer, size_t size,
+ off_t offset)
+{
+ return pread(dev->fd, buffer, size, offset);
+}
-void exfat_read_raw(void* buffer, size_t size, off_t offset, int fd)
+ssize_t exfat_pwrite(struct exfat_dev* dev, const void* buffer, size_t size,
+ off_t offset)
{
- if (pread(fd, buffer, size, offset) != size)
- exfat_bug("failed to read %zu bytes from file at %llu", size, offset);
+ return pwrite(dev->fd, buffer, size, offset);
}
-ssize_t exfat_read(const struct exfat* ef, const struct exfat_node* node,
+ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off_t offset)
{
cluster_t cluster;
if (size == 0)
return 0;
- cluster = exfat_advance_cluster(ef, node, node->start_cluster,
- offset / CLUSTER_SIZE(*ef->sb));
- if (CLUSTER_INVALID(cluster))
+ cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
+ if (CLUSTER_INVALID(*ef->sb, cluster))
{
- exfat_error("got invalid cluster");
- return -1;
+ exfat_error("invalid cluster 0x%x while reading", cluster);
+ return -EIO;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = MIN(size, node->size - offset);
while (remainder > 0)
{
+ if (CLUSTER_INVALID(*ef->sb, cluster))
+ {
+ exfat_error("invalid cluster 0x%x while reading", cluster);
+ return -EIO;
+ }
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
- exfat_read_raw(bufp, lsize, exfat_c2o(ef, cluster) + loffset, ef->fd);
+ if (exfat_pread(ef->dev, bufp, lsize,
+ exfat_c2o(ef, cluster) + loffset) < 0)
+ {
+ exfat_error("failed to read cluster %#x", cluster);
+ return -EIO;
+ }
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
- if (CLUSTER_INVALID(cluster))
+ }
+ if (!(node->attrib & EXFAT_ATTRIB_DIR) && !ef->ro && !ef->noatime)
+ exfat_update_atime(node);
+ return MIN(size, node->size - offset) - remainder;
+}
+
+ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
+ const void* buffer, size_t size, off_t offset)
+{
+ int rc;
+ cluster_t cluster;
+ const char* bufp = buffer;
+ off_t lsize, loffset, remainder;
+
+ if (offset > node->size)
+ {
+ rc = exfat_truncate(ef, node, offset, true);
+ if (rc != 0)
+ return rc;
+ }
+ if (offset + size > node->size)
+ {
+ rc = exfat_truncate(ef, node, offset + size, false);
+ if (rc != 0)
+ return rc;
+ }
+ if (size == 0)
+ return 0;
+
+ cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
+ if (CLUSTER_INVALID(*ef->sb, cluster))
+ {
+ exfat_error("invalid cluster 0x%x while writing", cluster);
+ return -EIO;
+ }
+
+ loffset = offset % CLUSTER_SIZE(*ef->sb);
+ remainder = size;
+ while (remainder > 0)
+ {
+ if (CLUSTER_INVALID(*ef->sb, cluster))
+ {
+ exfat_error("invalid cluster 0x%x while writing", cluster);
+ return -EIO;
+ }
+ lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
+ if (exfat_pwrite(ef->dev, bufp, lsize,
+ exfat_c2o(ef, cluster) + loffset) < 0)
{
- exfat_error("got invalid cluster");
- return -1;
+ exfat_error("failed to write cluster %#x", cluster);
+ return -EIO;
}
+ bufp += lsize;
+ loffset = 0;
+ remainder -= lsize;
+ cluster = exfat_next_cluster(ef, node, cluster);
}
+ if (!(node->attrib & EXFAT_ATTRIB_DIR))
+ /* directory's mtime should be updated by the caller only when it
+ creates or removes something in this directory */
+ exfat_update_mtime(node);
return size - remainder;
}
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