[PATCH] BLKGETSIZE64 support for parted 1.4.24

[Matt Domsch]

This adds BLKGETSIZE64 support for parted 1.4.24.  This code was added to 
the kernel ~2.4.15, but was broken until 2.4.18.  Likewise, in the 2.5.x 
tree, it was broken until 2.5.4.  This adds a test for a valid kernel, and 
uses it if possible.  This will be important when 64-bit block number 
devices become reality (soon in 2.5.x, likely backported to 2.4.x in 
the next 9-12 months).

A similar patch will be send against parted 1.6.2.

Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer, Lead Engineer, Architect
Dell Linux Solutions www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com
#1 US Linux Server provider for 2001 and Q1/2002! (IDC May 2002)

diff -urNp --exclude-from=/home/mdomsch/excludes --minimal 
parted-1.4.24/libparted/device.c parted-1.4.24.blkgetsize64/libparted/device.c
--- parted-1.4.24/libparted/device.c    Sat Jan 26 12:03:25 2002
+++ parted-1.4.24.blkgetsize64/libparted/device.c       Sun Jul 21 21:33:54 2002
@@ -40,6 +40,7 @@
 #include <sys/ioctl.h>
 #include <sys/sysmacros.h>
 #include <sys/stat.h>
+#include <sys/utsname.h>
 #include <scsi/scsi.h>
 
 #include <parted/parted.h>
@@ -58,6 +59,7 @@
 #define BLKSSZGET  _IO(0x12,104) /* get block device sector size */
 #define BLKGETLASTSECT  _IO(0x12,108) /* get last sector of block device */
 #define BLKSETLASTSECT  _IO(0x12,109) /* set last sector of block device */
+#define BLKGETSIZE64 _IOR(0x12,114,sizeof(uint64_t))   /* return device size 
in bytes (u64 *arg) */
 
 struct blkdev_ioctl_param {
        unsigned int block;
@@ -381,13 +383,54 @@ device_get_sector_size (PedDevice* dev)
 #endif /* !linux */
 }
 
+/**
+ * kernel_has_blkgetsize64()
+ *
+ * Returns: 0 on false, 1 on true
+ * True means linux kernel is 2.4.x, x>=18, or
+ *                         is 2.5.x, x>4, or
+ *                         is > 2.5
+ */
+#ifdef linux
+static int
+kernel_has_blkgetsize64(void)
+{
+        int major=0, minor=0, patch=0, parsed;
+        int rc;
+        struct utsname u;
+
+        memset(&u, 0, sizeof(u));
+        rc = uname(&u);
+        if (rc) return 0;
+
+        parsed = sscanf(u.release, "%d.%d.%d", &major, &minor, &patch);
+        if (parsed < 3) return 0;
+        if (major > 2) return 1;
+        if (major == 2 && minor > 5) return 1;
+        if (major == 2 && minor == 5 && patch >= 4) return 1;
+        if (major == 2 && minor == 4 && patch >= 18) return 1;
+        return 0;
+}
+#else
+static int
+kernel_has_blkgetsize64(void)
+{
+}
+#endif
+
 /* TODO: do a binary search if BLKGETSIZE doesn't work?! */
 static PedSector
 device_get_length (PedDevice* dev)
 {
        unsigned long           size;
+       uint64_t bytes=0;
 
        PED_ASSERT (dev->open_count, return 0);
+        if (kernel_has_blkgetsize64()) {
+                if (ioctl(dev->fd, BLKGETSIZE64, &bytes) == 0) {
+                        return bytes / device_get_sector_size(dev);
+               }
+       }
 
        if (ioctl (dev->fd, BLKGETSIZE, &size)) {
                ped_exception_throw (