--- grub-0.94/lib/device.c.26geom	2004-04-14 14:05:24.786938853 -0400

+++ grub-0.94/lib/device.c	2004-04-14 14:32:50.768600176 -0400

@@ -88,6 +88,122 @@

 #include <shared.h>

 #include <device.h>

+#if defined(__linux__)

+/* The 2.6 kernel has removed all of the geometry handling for IDE drives

+ * that did fixups for LBA, etc.  This means that the geometry we get

+ * with the ioctl has a good chance of being wrong.  So, we get to 

+ * also know about partition tables and try to read what the geometry

+ * is there. *grumble*   Very closely based on code from cfdisk

+ */

+static void get_kernel_geometry(int fd, int *cyl, int *heads, int *sectors) {

+    struct hd_geometry hdg;

+    

+    if (ioctl (fd, HDIO_GETGEO, &hdg))

+        return;

+

+    *cyl = hdg.cylinders;

+    *heads = hdg.heads;

+    *sectors = hdg.sectors;

+}

+

+struct partition {

+        unsigned char boot_ind;         /* 0x80 - active */

+        unsigned char head;             /* starting head */

+        unsigned char sector;           /* starting sector */

+        unsigned char cyl;              /* starting cylinder */

+        unsigned char sys_ind;          /* What partition type */

+        unsigned char end_head;         /* end head */

+        unsigned char end_sector;       /* end sector */

+        unsigned char end_cyl;          /* end cylinder */

+        unsigned char start4[4];        /* starting sector counting from 0 */

+        unsigned char size4[4];         /* nr of sectors in partition */

+};

+

+#define ALIGNMENT 2

+typedef union {

+    struct {

+	unsigned char align[ALIGNMENT];

+	unsigned char b[SECTOR_SIZE];

+    } c;

+    struct {

+	unsigned char align[ALIGNMENT];

+	unsigned char buffer[0x1BE];

+	struct partition part[4];

+	unsigned char magicflag[2];

+    } p;

+} partition_table;

+

+#define PART_TABLE_FLAG0 0x55

+#define PART_TABLE_FLAG1 0xAA

+

+static void

+get_partition_table_geometry(partition_table *bufp, int *cyl, int *heads, 

+                             int *sectors) {

+    struct partition *p;

+    int i,h,s,hh,ss;

+    int first = 1;

+    int bad = 0;

+

+    if (bufp->p.magicflag[0] != PART_TABLE_FLAG0 ||

+	bufp->p.magicflag[1] != PART_TABLE_FLAG1) {

+	    /* Matthew Wilcox: slightly friendlier version of

+	       fatal(_("Bad signature on partition table"), 3);

+	    */

+            fprintf(stderr, "Unknown partition table signature\n");

+	    return;

+    }

+

+    hh = ss = 0;

+    for (i=0; i<4; i++) {

+	p = &(bufp->p.part[i]);

+	if (p->sys_ind != 0) {

+	    h = p->end_head + 1;

+	    s = (p->end_sector & 077);

+	    if (first) {

+		hh = h;

+		ss = s;

+		first = 0;

+	    } else if (hh != h || ss != s)

+		bad = 1;

+	}

+    }

+

+    if (!first && !bad) {

+	*heads = hh;

+	*sectors = ss;

+    }

+}

+

+static void get_linux_geometry (int fd, struct geometry *geom) {

+    int kern_cyl = 0, kern_head = 0, kern_sectors = 0;

+    int pt_cyl = 0, pt_head = 0, pt_sectors = 0;

+    partition_table bufp;

+

+    get_kernel_geometry(fd, &kern_cyl, &kern_head, &kern_sectors);

+

+    if (read(fd, bufp.c.b, SECTOR_SIZE) == SECTOR_SIZE) {

+        get_partition_table_geometry(&bufp, &pt_cyl, &pt_head, &pt_sectors);

+    } else {

+        fprintf(stderr, "Unable to read partition table: %s\n", strerror(errno));

+    }

+

+    if (pt_head && pt_sectors) {

+        int cyl_size;

+

+        geom->heads = pt_head;

+        geom->sectors = pt_sectors;

+        cyl_size = pt_head * pt_sectors;

+        geom->cylinders = geom->total_sectors/cyl_size;

+    } else {

+        geom->heads = kern_head;

+        geom->sectors = kern_sectors;

+        geom->cylinders = kern_cyl;

+    }

+

+    return;

+}

+#endif

+

 /* Get the geometry of a drive DRIVE.  */

 void

 get_drive_geometry (struct geometry *geom, char **map, int drive)

@@ -100,20 +216,16 @@

 #if defined(__linux__)

   /* Linux */

   {

-    struct hd_geometry hdg;

     unsigned long nr;

-    if (ioctl (fd, HDIO_GETGEO, &hdg))

-      goto fail;

-

     if (ioctl (fd, BLKGETSIZE, &nr))

       goto fail;

-    

-    /* Got the geometry, so save it. */

-    geom->cylinders = hdg.cylinders;

-    geom->heads = hdg.heads;

-    geom->sectors = hdg.sectors;

+

     geom->total_sectors = nr;

+    get_linux_geometry(fd, geom);

+

+    if (!geom->heads && !geom->cylinders && !geom->sectors)

+        goto fail;

     close (fd);

     return;