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lomount: Major rewrite: handle large files and GPT partition.

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Signed-off-by: Tristan Gingold <tristan.gingold@bull.net>
This commit is contained in:
kaf24@firebug.cl.cam.ac.uk committed 2006-07-14 13:53:59 +01:00
1 parent 553243f2ea
commit 6af68a0b67
1 file changed
+267 -133
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tools/misc/lomount/lomount.c
+267 -133
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@@ -4,6 +4,9 @@
* Copyright (c) 2004 Jim Brown
* Copyright (c) 2004 Brad Watson
* Copyright (c) 2004 Mulyadi Santosa
* Major rewrite by Tristan Gingold:
* - Handle GPT partitions
* - Handle large files
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
@@ -41,6 +44,8 @@ enum
ERR_MOUNT // Other failure of mount command
};
#define _LARGEFILE_SOURCE
#define _FILE_OFFSET_BITS 64
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
@@ -63,22 +68,179 @@ struct pentry
unsigned char end_head;
unsigned int end_cylinder;
unsigned char end_sector;
unsigned long start_sector_abs;
unsigned long no_of_sectors_abs;
unsigned long long start_sector_abs;
unsigned long long no_of_sectors_abs;
};
int loadptable(const char *diskimage, struct pentry parttbl[], struct pentry **exttbl, int * valid)
static void
disp_entry (struct pentry *p)
{
printf ("%10llu - %10llu: %02x %x\n",
SECSIZE * p->start_sector_abs,
SECSIZE * (p->start_sector_abs + p->no_of_sectors_abs - 1),
p->system,
p->bootable);
}
static unsigned long
read_le4 (unsigned char *p)
{
return (unsigned long) p[0]
| ((unsigned long) p[1] << 8)
| ((unsigned long) p[2] << 16)
| ((unsigned long) p[3] << 24);
}
static unsigned long long
read_le8 (unsigned char *p)
{
return (unsigned long long) p[0]
| ((unsigned long long) p[1] << 8)
| ((unsigned long long) p[2] << 16)
| ((unsigned long long) p[3] << 24)
| ((unsigned long long) p[4] << 32)
| ((unsigned long long) p[5] << 40)
| ((unsigned long long) p[6] << 48)
| ((unsigned long long) p[7] << 56);
}
/* Return true if the partition table is a GPT protective MBR. */
static int
check_gpt (struct pentry *part, int nbr_part)
{
if (nbr_part != 4)
return 0;
if (part[0].system == 0xee
&& part[1].no_of_sectors_abs == 0
&& part[2].no_of_sectors_abs == 0
&& part[3].no_of_sectors_abs == 0)
return 1;
return 0;
}
static int
load_gpt (const char *diskimage, struct pentry *parttbl[])
{
FILE *fd;
size_t size;
int fail = 1;
int i, total_known_sectors = 0;
int fail = -1;
unsigned char data[SECSIZE];
unsigned long long entries_lba;
unsigned long entry_size;
struct pentry *part;
int nbr_part;
unsigned long long off;
int i;
fd = fopen(diskimage, "r");
if (fd == NULL)
{
perror(diskimage);
goto done;
}
fseeko (fd, SECSIZE, SEEK_SET);
size = fread (&data, 1, sizeof(data), fd);
if (size < (size_t)sizeof(data))
{
fprintf(stderr, "Could not read the GPT header of %s.\n",
diskimage);
goto done;
}
if (memcmp (data, "EFI PART", 8) != 0)
{
fprintf (stderr, "Bad GPT signature\n");
goto done;
}
entries_lba = read_le8 (&data[72]);
nbr_part = read_le4 (&data[80]);
entry_size = read_le4 (&data[84]);
#ifdef DEBUG
fprintf(stderr, "lba entries: %lu, nbr_part: %u, entry_size: %lu\n",
entries_lba, nbr_part, entry_size);
#endif
part = malloc (nbr_part * sizeof (struct pentry));
if (part == NULL)
{
fprintf(stderr,"Cannot allocate memory\n");
goto done;
}
memset (part, 0, nbr_part * sizeof (struct pentry));
*parttbl = part;
off = entries_lba * SECSIZE;
for (i = 0; i < nbr_part; i++)
{
static const char unused_guid[16] = {0};
fseeko (fd, off, SEEK_SET);
size = fread (&data, 1, 128, fd);
if (size < 128)
{
fprintf(stderr, "Could not read a GPT entry of %s.\n",
diskimage);
goto done;
}
if (memcmp (&data[0], unused_guid, 16) == 0)
{
part[i].start_sector_abs = 0;
part[i].no_of_sectors_abs = 0;
}
else
{
part[i].start_sector_abs = read_le8 (&data[32]);
part[i].no_of_sectors_abs = read_le8 (&data[40]);
#ifdef DEBUG
fprintf (stderr, "%d: %llu - %llu\n", i,
part[i].start_sector_abs,
part[i].no_of_sectors_abs);
#endif
/* Convert end to a number. */
part[i].no_of_sectors_abs -=
part[i].start_sector_abs - 1;
}
off += entry_size;
}
fail = nbr_part;
done:
if (fd)
fclose(fd);
return fail;
}
/* Read an MBR entry. */
static void
read_mbr_record (unsigned char pi[16], struct pentry *res)
{
res->bootable = *pi;
res->start_head = *(pi + 1);
res->start_cylinder = *(pi + 3) | ((*(pi + 2) << 2) & 0x300);
res->start_sector = *(pi + 2) & 0x3f;
res->system = *(pi + 4);
res->end_head = *(pi + 5);
res->end_cylinder = *(pi + 7) | ((*(pi + 6) << 2) & 0x300);
res->end_sector = *(pi + 6) & 0x3f;
res->start_sector_abs = read_le4 (&pi[8]);
res->no_of_sectors_abs = read_le4 (&pi[12]);
}
/* Returns the number of partitions, -1 in case of failure. */
int load_mbr(const char *diskimage, struct pentry *parttbl[])
{
FILE *fd;
size_t size;
int fail = -1;
int nbr_part;
int i;
unsigned char *pi;
unsigned char data [SECSIZE];
unsigned long extent = 0, old_extent = 0, e_count = 1;
struct pentry exttbls[4];
unsigned long long extent;
struct pentry *part;
*valid = 0;
nbr_part = 0;
fd = fopen(diskimage, "r");
if (fd == NULL)
@@ -92,102 +254,61 @@ int loadptable(const char *diskimage, struct pentry parttbl[], struct pentry **e
fprintf(stderr, "Could not read the entire first sector of %s.\n", diskimage);
goto done;
}
if (data [510] != 0x55 || data [511] != 0xaa)
{
fprintf(stderr,"MBR signature mismatch (invalid partition table?)\n");
goto done;
}
/* There is at most 4*4 + 4 = 20 entries, also there should be only
one extended partition. */
part = malloc (20 * sizeof (struct pentry));
if (part == NULL)
{
fprintf(stderr,"Cannot allocate memory\n");
goto done;
}
*parttbl = part;
/* Read MBR. */
nbr_part = 4;
for (i = 0; i < 4; i++)
{
pi = &data [446 + 16 * i];
parttbl [i].bootable = *pi;
parttbl [i].start_head = *(pi + 1);
parttbl [i].start_cylinder = *(pi + 3) | ((*(pi + 2) << 2) & 0x300);
parttbl [i].start_sector = *(pi + 2) & 0x3f;
parttbl [i].system = *(pi + 4);
parttbl [i].end_head = *(pi + 5);
parttbl [i].end_cylinder = *(pi + 7) | ((*(pi + 6) << 2) & 0x300);
parttbl [i].end_sector = *(pi + 6) & 0x3f;
parttbl [i].start_sector_abs =
(unsigned long) *(pi + 8) | ((unsigned long) *(pi + 9) << 8) | ((unsigned long) *(pi + 10) << 16) | ((unsigned long) *(pi + 11) << 24);
parttbl [i].no_of_sectors_abs =
(unsigned long) *(pi + 12) | ((unsigned long) *(pi + 13) << 8) | ((unsigned long) *(pi + 14) << 16) | ((unsigned long) *(pi + 15) << 24);
if (parttbl[i].system == 0xF || parttbl[i].system == 0x5)
{
extent = parttbl[i].start_sector_abs * SECSIZE;
/* save the location of the "real" extended partition */
old_extent = extent;
}
read_mbr_record (pi, &part[i]);
}
*valid = (data [510] == 0x55 && data [511] == 0xaa) ? 1 : 0;
/* Read extended partitions. */
for (i = 0; i < 4; i++)
{
total_known_sectors += parttbl[i].no_of_sectors_abs;
}
/* Extended Partition layout format was obtained from
http://wigner.cped.ornl.gov/the-gang/att-0520/03-Partition.htm */
#ifdef DEBUG
if (extent != 0)
{
printf("extended partition detected at offset %ld\n", extent);
}
#endif
while (extent != 0)
{
/* according to realloc(3) passing NULL as pointer is same as calling malloc() */
exttbl[0] = realloc(exttbl[0], e_count * sizeof(struct pentry));
fseek(fd, extent, SEEK_SET);
size = fread (&data, 1, sizeof(data), fd);
if (size < (size_t)sizeof(data))
if (part[i].system == 0xF || part[i].system == 0x5)
{
fprintf(stderr, "Could not read extended partition of %s.", diskimage);
goto done;
}
/* only first 2 entrys are used in extented partition tables */
for (i = 0; i < 2; i++)
{
pi = &data [446 + 16 * i];
exttbls [i].bootable = *pi;
exttbls [i].start_head = *(pi + 1);
exttbls [i].start_cylinder = *(pi + 3) | ((*(pi + 2) << 2) & 0x300);
exttbls [i].start_sector = *(pi + 2) & 0x3f;
exttbls [i].system = *(pi + 4);
exttbls [i].end_head = *(pi + 5);
exttbls [i].end_cylinder = *(pi + 7) | ((*(pi + 6) << 2) & 0x300);
exttbls [i].end_sector = *(pi + 6) & 0x3f;
exttbls [i].start_sector_abs =
(unsigned long) *(pi + 8) | ((unsigned long) *(pi + 9) << 8) | ((unsigned long) *(pi + 10) << 16) | ((unsigned long) *(pi + 11) << 24);
exttbls [i].no_of_sectors_abs =
(unsigned long) *(pi + 12) | ((unsigned long) *(pi + 13) << 8) | ((unsigned long) *(pi + 14) << 16) | ((unsigned long) *(pi + 15) << 24);
if (i == 0)
int j;
extent = part[i].start_sector_abs * SECSIZE;
fseeko (fd, extent, SEEK_SET);
size = fread (&data, 1, sizeof(data), fd);
if (size < (size_t)sizeof(data))
{
//memmove((void *)exttbl[e_count-1], (void *)exttbls[i], sizeof(struct pentry));
//memmove() seems broken!
exttbl[0][e_count-1].bootable = exttbls [i].bootable;
exttbl[0][e_count-1].start_head = exttbls [i].start_head;
exttbl[0][e_count-1].start_cylinder = exttbls [i].start_cylinder;
exttbl[0][e_count-1].start_sector = exttbls [i].start_sector;
exttbl[0][e_count-1].system = exttbls [i].system;
exttbl[0][e_count-1].end_head = exttbls [i].end_head;
exttbl[0][e_count-1].end_cylinder = exttbls [i].end_cylinder;
exttbl[0][e_count-1].end_sector = exttbls [i].end_sector;
exttbl[0][e_count-1].start_sector_abs = exttbls [i].start_sector_abs;
exttbl[0][e_count-1].no_of_sectors_abs = exttbls [i].no_of_sectors_abs;
/* adjust for start of image instead of start of ext partition */
exttbl[0][e_count-1].start_sector_abs += (extent/SECSIZE);
#ifdef DEBUG
printf("extent %ld start_sector_abs %ld\n", extent, exttbl[0][e_count-1].start_sector_abs);
#endif
//else if (parttbl[i].system == 0x5)
fprintf(stderr, "Could not read extended partition of %s.", diskimage);
goto done;
}
else if (i == 1)
for (j = 0; j < 4; j++)
{
extent = (exttbls[i].start_sector_abs * SECSIZE);
if (extent)
extent += old_extent;
int n;
pi = &data [446 + 16 * j];
n = nbr_part + j;
read_mbr_record (pi, &part[n]);
}
nbr_part += 4;
}
e_count ++;
}
#ifdef DEBUG
printf("e_count = %ld\n", e_count);
#endif
fail = 0;
fail = nbr_part;
done:
if (fd)
@@ -197,8 +318,8 @@ done:
void usage(void)
{
fprintf(stderr, "You must specify at least -diskimage and -partition.\n");
fprintf(stderr, "All other arguments are passed through to 'mount'.\n");
fprintf(stderr, "Usage: lomount [-verbose] [OPTIONS] -diskimage FILE -partition NUM [OPTIONS]\n");
fprintf(stderr, "All OPTIONS are passed through to 'mount'.\n");
fprintf(stderr, "ex. lomount -t fs-type -diskimage hda.img -partition 1 /mnt\n");
exit(ERR_USAGE);
}
@@ -206,14 +327,17 @@ void usage(void)
int main(int argc, char ** argv)
{
int status;
struct pentry perttbl [4];
struct pentry *exttbl[1], *parttbl;
int nbr_part;
struct pentry *parttbl;
char buf[BUF], argv2[BUF];
const char * diskimage = 0;
int partition = 0, sec, num = 0, pnum = 0, i, valid;
const char * diskimage = NULL;
int partition = 0;
unsigned long long sec, num, pnum;
int i;
size_t argv2_len = sizeof(argv2);
int verbose = 0;
argv2[0] = '\0';
exttbl[0] = NULL;
for (i = 1; i < argc; i ++)
{
@@ -231,6 +355,10 @@ int main(int argc, char ** argv)
i++;
partition = atoi(argv[i]);
}
else if (strcmp(argv[i], "-verbose")==0)
{
verbose++;
}
else
{
size_t len = strlen(argv[i]);
@@ -241,59 +369,65 @@ int main(int argc, char ** argv)
len -= (len+1);
}
}
if (! diskimage || partition < 1)
if (! diskimage || partition < 0)
usage();
if (loadptable(diskimage, perttbl, exttbl, &valid))
nbr_part = load_mbr(diskimage, &parttbl);
if (check_gpt (parttbl, nbr_part)) {
free (parttbl);
nbr_part = load_gpt (diskimage, &parttbl);
}
if (nbr_part < 0)
return ERR_PART_PARSE;
if (!valid)
if (partition == 0)
{
fprintf(stderr, "Warning: disk image does not appear to describe a valid partition table.\n");
printf("Please specify a partition number. Table is:\n");
printf("Num Start - End OS Bootable\n");
for (i = 0; i < nbr_part; i++)
{
if (parttbl[i].no_of_sectors_abs != 0)
{
printf ("%2d: ", i + 1);
disp_entry (&parttbl[i]);
}
}
if (partition == 0)
return 0;
}
/* NOTE: need to make sure this always rounds down */
//sec = total_known_sectors / sizeof_diskimage;
/* The above doesn't work unless the disk image is completely filled by
partitions ... unused space will thrown off the sector size. The calculation
assumes the disk image is completely filled, and that the few sectors used
to store the partition table/MBR are few enough that the calculated value is
off by (larger than) a value less than one. */
/* The above doesn't work unless the disk image is completely
filled by partitions ... unused space will thrown off the
sector size. The calculation assumes the disk image is
completely filled, and that the few sectors used to store
the partition table/MBR are few enough that the calculated
value is off by (larger than) a value less than one. */
sec = 512; /* TODO: calculate real sector size */
#ifdef DEBUG
printf("sec: %d\n", sec);
#endif
if (partition > 4)
if (partition > nbr_part)
{
if (exttbl[0] == NULL)
{
fprintf(stderr, "No extended partitions were found in %s.\n", diskimage);
return ERR_NO_EPART;
}
parttbl = exttbl[0];
if (parttbl[partition-5].no_of_sectors_abs == 0)
{
fprintf(stderr, "Partition %d was not found in %s.\n", partition, diskimage);
return ERR_NO_PART;
}
partition -= 4;
}
else
{
parttbl = perttbl;
if (parttbl[partition-1].no_of_sectors_abs == 0)
{
fprintf(stderr, "Partition %d was not found in %s.\n", partition, diskimage);
return ERR_NO_PART;
}
fprintf(stderr, "Bad partition number\n");
return ERR_NO_EPART;
}
num = parttbl[partition-1].start_sector_abs;
if (num == 0)
{
fprintf(stderr, "Partition %d was not found in %s.\n",
partition, diskimage);
return ERR_NO_PART;
}
pnum = sec * num;
#ifdef DEBUG
printf("offset = %d\n", pnum);
#endif
snprintf(buf, sizeof(buf), "mount -oloop,offset=%d %s %s", pnum, diskimage, argv2);
#ifdef DEBUG
printf("%s\n", buf);
#endif
snprintf(buf, sizeof(buf), "mount -oloop,offset=%lld %s %s",
pnum, diskimage, argv2);
if (verbose)
printf("%s\n", buf);
status = system(buf);
if (WIFEXITED(status))
status = WEXITSTATUS(status);
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