From 268cefe6cb34fb8799b34187677154071ad45eb7 Mon Sep 17 00:00:00 2001
From: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date: Thu, 24 Jul 2008 00:30:21 +0200
Subject: [PATCH] lib: blkdev.c clean up, non-linux support

[kzak@redhat.com: split the original patch to small patches]

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 include/blkdev.h | 10 +++++---
 lib/blkdev.c     | 67 ++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 66 insertions(+), 11 deletions(-)

diff --git a/include/blkdev.h b/include/blkdev.h
index 1f0fe674..1b10569b 100644
--- a/include/blkdev.h
+++ b/include/blkdev.h
@@ -6,7 +6,7 @@
 
 #define DEFAULT_SECTOR_SIZE       512
 
-#ifndef BLKROSET
+#if !defined(BLKROSET) && defined(__linux__)
 
 #define BLKROSET   _IO(0x12,93)	/* set device read-only (0 = read-write) */
 #define BLKROGET   _IO(0x12,94)	/* get read-only status (0 = read_write) */
@@ -34,7 +34,9 @@
 #endif /* BLKROSET */
 
 #ifndef HDIO_GETGEO
-#define HDIO_GETGEO 0x0301
+# ifdef __linux__
+#  define HDIO_GETGEO 0x0301
+# endif
 struct hd_geometry {
 	unsigned char heads;
 	unsigned char sectors;
@@ -43,6 +45,9 @@ struct hd_geometry {
 };
 #endif
 
+/* Determine size in bytes */
+off_t blkdev_find_size (int fd);
+
 /* get size in bytes */
 int blkdev_get_size(int fd, unsigned long long *bytes);
 
@@ -52,5 +57,4 @@ int blkdev_get_sectors(int fd, unsigned long long *sectors);
 /* get hardware sector size */
 int blkdev_get_sector_size(int fd, int *sector_size);
 
-
 #endif /* BLKDEV_H */
diff --git a/lib/blkdev.c b/lib/blkdev.c
index 29c5d0bd..79a366ca 100644
--- a/lib/blkdev.c
+++ b/lib/blkdev.c
@@ -1,30 +1,74 @@
 
 #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)
 {
-	unsigned long size;
-	int ver = get_linux_version();
+	/* 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))) {
-
+	   (ver >= KERNEL_VERSION (2,4,18) && ver < KERNEL_VERSION (2,5,0)))
+#endif
 		if (ioctl(fd, BLKGETSIZE64, bytes) >= 0)
 			return 0;
-	}
-	if (ioctl(fd, BLKGETSIZE, &size) >= 0) {
-		*bytes = ((unsigned long long)size << 9);
-		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 */
@@ -45,14 +89,21 @@ blkdev_get_sectors(int fd, unsigned long long *sectors)
 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
 }
 
 
-- 
2.39.5