1 files changed, 144 insertions, 0 deletions
diff --git a/lib/blkdev.c b/lib/blkdev.c
new file mode 100644
index 0000000..7c6c7ba
--- /dev/null
+++ b/lib/blkdev.c
@@ -0,0 +1,144 @@
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "blkdev.h"
+#include "linux_version.h"
+
+static long
+blkdev_valid_offset (int fd, off_t offset) {
+	char ch;
+
+	if (lseek (fd, offset, 0) < 0)
+		return 0;
+	if (read (fd, &ch, 1) < 1)
+		return 0;
+	return 1;
+}
+
+off_t
+blkdev_find_size (int fd) {
+	off_t high, low;
+
+	low = 0;
+	for (high = 1; high > 0 && blkdev_valid_offset (fd, high); high *= 2)
+		low = high;
+	while (low < high - 1)
+	{
+		const off_t mid = (low + high) / 2;
+
+		if (blkdev_valid_offset (fd, mid))
+			low = mid;
+		else
+			high = mid;
+	}
+	blkdev_valid_offset (fd, 0);
+	return (low + 1);
+}
+
+/* get size in bytes */
+int
+blkdev_get_size(int fd, unsigned long long *bytes)
+{
+	/* TODO: use stat as well */
+
+#ifdef BLKGETSIZE64
+#ifdef __linux__
+	int ver = get_linux_version();
+	/* kernels 2.4.15-2.4.17, had a broken BLKGETSIZE64 */
+	if (ver >= KERNEL_VERSION (2,6,0) ||
+	   (ver >= KERNEL_VERSION (2,4,18) && ver < KERNEL_VERSION (2,5,0)))
+#endif
+		if (ioctl(fd, BLKGETSIZE64, bytes) >= 0)
+			return 0;
+#endif /* BLKGETSIZE64 */
+
+#ifdef BLKGETSIZE
+	{
+		unsigned long size;
+
+		if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
+			*bytes = ((unsigned long long)size << 9);
+			return 0;
+		}
+	}
+
+	return -1;
+#endif /* BLKGETSIZE */
+
+	*bytes = blkdev_find_size(fd);
+	return 0;
+}
+
+/* get 512-byte sector count */
+int
+blkdev_get_sectors(int fd, unsigned long long *sectors)
+{
+	unsigned long long bytes;
+
+	if (blkdev_get_size(fd, &bytes) == 0) {
+		*sectors = (bytes >> 9);
+		return 0;
+	}
+
+	return -1;
+}
+
+/* get hardware sector size */
+int
+blkdev_get_sector_size(int fd, int *sector_size)
+{
+#ifdef BLKSSZGET
+#ifdef __linux__
+	if (get_linux_version() < KERNEL_VERSION(2,3,3)) {
+		*sector_size = DEFAULT_SECTOR_SIZE;
+		return 0;
+	}
+#endif
+	if (ioctl(fd, BLKSSZGET, sector_size) >= 0)
+		return 0;
+
+	return -1;
+#else
+	*sector_size = DEFAULT_SECTOR_SIZE;
+	return 0;
+#endif
+}
+
+
+#ifdef TEST_PROGRAM
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <err.h>
+int
+main(int argc, char **argv)
+{
+	unsigned long long bytes;
+	unsigned long long sectors;
+	int sector_size;
+	int fd;
+
+	if (argc != 2) {
+		fprintf(stderr, "usage: %s device\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if ((fd = open(argv[1], O_RDONLY)) < 0)
+		err(EXIT_FAILURE, "open %s failed", argv[1]);
+
+	if (blkdev_get_size(fd, &bytes) < 0)
+		err(EXIT_FAILURE, "blkdev_get_size() failed");
+	if (blkdev_get_sectors(fd, &sectors) < 0)
+		err(EXIT_FAILURE, "blkdev_get_sectors() failed");
+	if (blkdev_get_sector_size(fd, &sector_size) < 0)
+		err(EXIT_FAILURE, "blkdev_get_sector_size() failed");
+
+	printf("bytes %llu\n", bytes);
+	printf("sectors %llu\n", sectors);
+	printf("sectorsize %d\n", sector_size);
+
+	return EXIT_SUCCESS;
+}
+#endif /* TEST_PROGRAM */