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Date: 2005-11-11
Author: Otavio Salvador
Comment: Stolen from Fedora grub package.
Put geometry discover inside of grub code since kernel 2.6
doesn't do that anymore.
--- grub-0.95/lib/device.c.26geom 2004-11-30 16:33:00.186025728 -0500
+++ grub-0.95/lib/device.c 2004-11-30 16:45:09.073218032 -0500
@@ -131,6 +131,152 @@
#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, long long *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, long long *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 long long my_lseek (unsigned int fd, long long offset,
+ unsigned int origin)
+{
+#if defined(__linux__) && (!defined(__GLIBC__) || \
+ ((__GLIBC__ < 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ < 1))))
+ /* Maybe libc doesn't have large file support. */
+ loff_t offset, result;
+ static int _llseek (uint filedes, ulong hi, ulong lo,
+ loff_t *res, uint wh);
+ _syscall5 (int, _llseek, uint, filedes, ulong, hi, ulong, lo,
+ loff_t *, res, uint, wh);
+
+ if (_llseek (fd, offset >> 32, offset & 0xffffffff, &result, SEEK_SET) < 0)
+ return (long long) -1;
+ return result;
+#else
+ return lseek(fd, offset, SEEK_SET);
+#endif
+}
+
+static void get_linux_geometry (int fd, struct geometry *geom) {
+ long long kern_cyl = 0; int kern_head = 0, kern_sectors = 0;
+ long long pt_cyl = 0; int pt_head = 0, pt_sectors = 0;
+ partition_table bufp;
+ char *buff, *buf_unaligned;
+
+ buf_unaligned = malloc(sizeof(partition_table) + 4095);
+ buff = (char *) (((unsigned long)buf_unaligned + 4096 - 1) &
+ (~(4096-1)));
+
+ get_kernel_geometry(fd, &kern_cyl, &kern_head, &kern_sectors);
+
+ if (my_lseek (fd, 0*SECTOR_SIZE, SEEK_SET) < 0) {
+ fprintf(stderr, "Unable to seek");
+ }
+
+ if (read(fd, buff, SECTOR_SIZE) == SECTOR_SIZE) {
+ memcpy(bufp.c.b, buff, 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)
@@ -151,21 +297,16 @@
#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;
goto success;
}
@@ -841,6 +982,7 @@
{
char dev[PATH_MAX]; /* XXX */
int fd;
+ off_t offset = (off_t) sector * (off_t) SECTOR_SIZE;
if ((partition & 0x00FF00) != 0x00FF00)
{
@@ -874,35 +1016,13 @@
errnum = ERR_NO_PART;
return 0;
}
-
-#if defined(__linux__) && (!defined(__GLIBC__) || \
- ((__GLIBC__ < 2) || ((__GLIBC__ == 2) && (__GLIBC_MINOR__ < 1))))
- /* Maybe libc doesn't have large file support. */
- {
- loff_t offset, result;
- static int _llseek (uint filedes, ulong hi, ulong lo,
- loff_t *res, uint wh);
- _syscall5 (int, _llseek, uint, filedes, ulong, hi, ulong, lo,
- loff_t *, res, uint, wh);
- offset = (loff_t) sector * (loff_t) SECTOR_SIZE;
- if (_llseek (fd, offset >> 32, offset & 0xffffffff, &result, SEEK_SET))
- {
- errnum = ERR_DEV_VALUES;
- return 0;
- }
- }
-#else
- {
- off_t offset = (off_t) sector * (off_t) SECTOR_SIZE;
- if (lseek (fd, offset, SEEK_SET) != offset)
- {
- errnum = ERR_DEV_VALUES;
- return 0;
- }
- }
-#endif
+ if (my_lseek(fd, offset, SEEK_SET) != offset)
+ {
+ errnum = ERR_DEV_VALUES;
+ return 0;
+ }
if (write (fd, buf, size * SECTOR_SIZE) != (size * SECTOR_SIZE))
{
|
