+#include <string.h>
+#ifdef __APPLE__
+#include <sys/disk.h>
+#endif
+#ifdef USE_UBLIO
+#include <sys/uio.h>
+#include <ublio.h>
+#endif
+
+struct exfat_dev
+{
+ int fd;
+ enum exfat_mode mode;
+ off_t size; /* in bytes */
+#ifdef USE_UBLIO
+ off_t pos;
+ ublio_filehandle_t ufh;
+#endif
+};
+
+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);
+ return -1;
+ }
+#endif
+ return fd;
+}
+
+struct exfat_dev* exfat_open(const char* spec, enum exfat_mode mode)
+{
+ struct exfat_dev* dev;
+ struct stat stbuf;
+#ifdef USE_UBLIO
+ struct ublio_param up;
+#endif
+
+ 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", spec);
+ 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", spec);
+ 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'", spec);
+ 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;
+ }
+
+#ifdef __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
+#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 device size");
+ return NULL;
+ }
+ }
+
+#ifdef USE_UBLIO
+ memset(&up, 0, sizeof(struct ublio_param));
+ up.up_blocksize = 256 * 1024;
+ up.up_items = 64;
+ up.up_grace = 32;
+ up.up_priv = &dev->fd;
+
+ dev->pos = 0;
+ dev->ufh = ublio_open(&up);
+ if (dev->ufh == NULL)
+ {
+ close(dev->fd);
+ free(dev);
+ exfat_error("failed to initialize ublio");
+ return NULL;
+ }
+#endif