busybox/archival/libunarchive/get_header_cpio.c

136 lines
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C
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2001-10-25 19:48:08 +05:30
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Library General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "unarchive.h"
#include "libbb.h"
struct hardlinks {
file_header_t *entry;
int inode;
struct hardlinks *next;
};
file_header_t *get_header_cpio(FILE *src_stream)
{
file_header_t *cpio_entry = NULL;
char cpio_header[110];
int namesize;
char dummy[16];
int major, minor, nlink, inode;
static struct hardlinks *saved_hardlinks = NULL;
static int pending_hardlinks = 0;
if (pending_hardlinks) { /* Deal with any pending hardlinks */
struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
while (tmp) {
if (tmp->entry->link_name) { /* Found a hardlink ready to be extracted */
cpio_entry = tmp->entry;
if (oldtmp) oldtmp->next = tmp->next; /* Remove item from linked list */
else saved_hardlinks = tmp->next;
free(tmp);
return (cpio_entry);
}
oldtmp = tmp;
tmp = tmp->next;
}
pending_hardlinks = 0; /* No more pending hardlinks, read next file entry */
}
/* There can be padding before archive header */
seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
if (fread(cpio_header, 1, 110, src_stream) == 110) {
archive_offset += 110;
if (strncmp(cpio_header, "07070", 5) != 0) {
error_msg("Unsupported format or invalid magic");
return(NULL);
}
switch (cpio_header[5]) {
case '2': /* "crc" header format */
/* Doesnt do the crc check yet */
case '1': /* "newc" header format */
cpio_entry = (file_header_t *) xcalloc(1, sizeof(file_header_t));
sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
dummy, &inode, (unsigned int*)&cpio_entry->mode,
(unsigned int*)&cpio_entry->uid, (unsigned int*)&cpio_entry->gid,
&nlink, &cpio_entry->mtime, &cpio_entry->size,
dummy, &major, &minor, &namesize, dummy);
cpio_entry->name = (char *) xcalloc(1, namesize);
fread(cpio_entry->name, 1, namesize, src_stream); /* Read in filename */
archive_offset += namesize;
/* Skip padding before file contents */
seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
if (strcmp(cpio_entry->name, "TRAILER!!!") == 0) {
printf("%d blocks\n", (int) (archive_offset % 512 ? (archive_offset / 512) + 1 : archive_offset / 512)); /* Always round up */
if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
while (tmp) {
error_msg("%s not created: cannot resolve hardlink", tmp->entry->name);
oldtmp = tmp;
tmp = tmp->next;
free (oldtmp->entry->name);
free (oldtmp->entry);
free (oldtmp);
}
saved_hardlinks = NULL;
pending_hardlinks = 0;
}
return(NULL);
}
if (S_ISLNK(cpio_entry->mode)) {
cpio_entry->link_name = (char *) xcalloc(1, cpio_entry->size + 1);
fread(cpio_entry->link_name, 1, cpio_entry->size, src_stream);
archive_offset += cpio_entry->size;
cpio_entry->size = 0; /* Stop possiable seeks in future */
}
if (nlink > 1 && !S_ISDIR(cpio_entry->mode)) {
if (cpio_entry->size == 0) { /* Put file on a linked list for later */
struct hardlinks *new = xmalloc(sizeof(struct hardlinks));
new->next = saved_hardlinks;
new->inode = inode;
new->entry = cpio_entry;
saved_hardlinks = new;
return(get_header_cpio(src_stream)); /* Recurse to next file */
} else { /* Found the file with data in */
struct hardlinks *tmp = saved_hardlinks;
pending_hardlinks = 1;
while (tmp) {
if (tmp->inode == inode) {
tmp->entry->link_name = xstrdup(cpio_entry->name);
nlink--;
}
tmp = tmp->next;
}
if (nlink > 1) error_msg("error resolving hardlink: did you create the archive with GNU cpio 2.0-2.2?");
}
}
cpio_entry->device = (major << 8) | minor;
break;
default:
error_msg("Unsupported format");
return(NULL);
}
if (ferror(src_stream) || feof(src_stream)) {
perror_msg("Stream error");
return(NULL);
}
}
return(cpio_entry);
}