Attachment 46324 Details for Bug 103031

C program to check and maybe fix the problem

FixCHS.c (text/x-csrc), 3.38 KB, created by Torsten Duwe on 2005-08-17 14:35:16 UTC

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Creator: Torsten Duwe

Created: 2005-08-17 14:35:16 UTC

Size: 3.38 KB

patch

obsolete

>#include <sys/types.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <unistd.h>
>#include <fcntl.h>
>#include <err.h>
>
>unsigned char buf[512];
>#define PARTTAB_OFFSET 446
>
>/* The BIOS' idea of the disk geometry */
>int cylinders, heads, sectors;
>
>/* -------------------- from fdisk.c --------------------*/
>#define sector(s)       ((s) & 0x3f)
>#define cylinder(s, c)  ((c) | (((s) & 0xc0) << 2))
>#define hsc2sector(h,s,c) (sector(s) - 1 + sectors * \
>                                ((h) + heads * cylinder(s,c)))
>#define set_hsc(h,s,c,sector) { \
>                                s = sector % sectors + 1;       \
>                                sector /= sectors;      \
>                                h = sector % heads;     \
>                                sector /= heads;        \
>                                c = sector & 0xff;      \
>                                s |= (sector >> 2) & 0xc0;      \
>                        }
>/* -------------------- from fdisk.c --------------------*/
>
>typedef struct
>{
>  unsigned char h;
>  unsigned char s;
>  unsigned char c;
>}
>  chs_bytes;
>
>
>typedef struct
>{
>  unsigned char flags;
>  chs_bytes start_chs;
>  unsigned char sysId;
>  chs_bytes end_chs;
>  /* XXX assumes wrong-endian native && sizeof(int)==4 */
>  unsigned int lstart;
>  unsigned int lsize;
>}
>  part_entry;
>
>int read_ascii(char * fname)
>{
>  FILE * F;
>  int ret = 0;
>
>  if ((F = fopen(fname, "r")) == 0)
>    return 0;
>
>  if (fscanf(F, "%d", &ret) < 1)
>    ret = 0;
>  
>  fclose(F);
>  return ret;
>}
>
>int
>check_part(int n, int do_fix)
>{
>  int c, h, s;
>  
>  part_entry * parttab = (part_entry *)(buf+PARTTAB_OFFSET);
>  n--;
>
>  if(parttab[n].lstart / (heads*sectors) > 1023) /* out of range anyways */
>    return 0;
>  if(parttab[n].sysId == 0)	/* unused partition */
>    return 0;
>
>  set_hsc(h,s,c,parttab[n].lstart);
>  
>  if (c != parttab[n].start_chs.c ||
>      h != parttab[n].start_chs.h ||
>      s != parttab[n].start_chs.s)
>    {
>      printf("Partition %d mismatch\n", n+1);
>      printf("[ %02x %02x %02x ] ",
>	     parttab[n].start_chs.h,
>	     parttab[n].start_chs.s,
>	     parttab[n].start_chs.c);
>      printf("[ %02x %02x %02x ] ", h, s, c);
>      if (do_fix)
>	{
>	  parttab[n].start_chs.c = c;
>	  parttab[n].start_chs.h = h;
>	  parttab[n].start_chs.s = s;
>	  printf("(Fixed)\n");
>	  return 1;
>	}
>      putchar('\n');
>    }
>  return 0;
>}
>
>int
>main(int argc, char ** argv)
>{
>  
>  if (chdir("/sys/firmware/edd/int13_dev80") != 0)
>    err(1, "edd module loaded?\n chdir to /sys/firmware/edd/int13_dev80");
>
>  cylinders = read_ascii("legacy_max_cylinder");
>  heads	    = read_ascii("legacy_max_head");
>  sectors   = read_ascii("legacy_sectors_per_track");
>  heads++;
>
>  if (cylinders*heads*sectors == 0)
>    errx(1, "cannot determine BIOS geometry");
>
>  //  printf("%d/%d/%d\n", c, h, s);
>  
>  chdir("/dev");
>  if (argc > 1)
>    {
>      int fd, i;
>      
>      fd = open(argv[1], O_RDWR, 0);
>      if (fd < 0)
>	err(1, "Cannot open %s", argv[1]);
>
>      if (read(fd, buf, 512) < 512)
>	err(1, "Read from %s", argv[1]);
>
>      if (lseek(fd, 0, SEEK_SET) != 0)
>	err(1, "%s not seekable", argv[1]);
>
>      if (argc > 2)
>	{
>	  int partno;
>	  
>	  partno = atoi(argv[2]);
>	  if (partno < 1 || partno > 4)
>	    errx(1, "Usage: %s <device> [primary_partition_number]", argv[0] );
>	  if (check_part(partno, 1) > 0)
>	    {
>#ifdef notyet
>	      /* write(fd, buf, 512); */
>#endif
>	    }
>	}
>      else
>	for (i=1; i<=4; i++)
>	  check_part(i, 0);
>    }
>
>  return 0;
>}

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Attachments on bug 103031: 45848 | 45849 | 45850 | 45942 | 46137 | 46324 | 48344 | 48345 | 48346 | 48347 | 48815 | 49022 | 49023