busybox/libbb/get_ar_headers.c

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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) tons of folks. Tracking down who wrote what
* isn't something I'm going to worry about... If you wrote something
* here, please feel free to acknowledge your work.
*
* 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
* 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
*
* Based in part on code from sash, Copyright (c) 1999 by David I. Bell
* Permission has been granted to redistribute this code under the GPL.
*
*/
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "libbb.h"
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extern ar_headers_t *get_ar_headers(FILE *in_file)
{
typedef struct raw_ar_header_s { /* Byte Offset */
char name[16]; /* 0-15 */
char date[12]; /* 16-27 */
char uid[6];
char gid[6]; /* 28-39 */
char mode[8]; /* 40-47 */
char size[10]; /* 48-57 */
char fmag[2]; /* 58-59 */
} raw_ar_header_t;
raw_ar_header_t raw_ar_header;
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ar_headers_t *ar_list, *ar_tmp, *ar_entry;
char ar_magic[8];
char *long_name=NULL;
/* check ar magic */
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if (fread(ar_magic, 1, 8, in_file) != 8) {
error_msg("cannot read magic");
return(NULL);
}
if (strncmp(ar_magic,"!<arch>",7) != 0) {
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error_msg("invalid magic");
return(NULL);
}
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ar_list = (ar_headers_t *) xcalloc(1, sizeof(ar_headers_t));
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while (fread((char *) &raw_ar_header, 1, 60, in_file) == 60) {
ar_entry = (ar_headers_t *) xcalloc(1, sizeof(ar_headers_t));
/* check the end of header markers are valid */
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if ((raw_ar_header.fmag[0] != '`') || (raw_ar_header.fmag[1] != '\n')) {
char newline;
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if (raw_ar_header.fmag[1] != '`') {
break;
}
/* some version of ar, have an extra '\n' after each entry */
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fread(&newline, 1, 1, in_file);
if (newline!='\n') {
break;
}
/* fix up the header, we started reading 1 byte too early due to a '\n' */
memmove((char *) &raw_ar_header, (char *)&raw_ar_header+1, 59);
/* dont worry about adding the last '\n', we dont need it now */
}
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ar_entry->size = (size_t) atoi(raw_ar_header.size);
/* long filenames have '/' as the first character */
if (raw_ar_header.name[0] == '/') {
if (raw_ar_header.name[1] == '/') {
/* multiple long filenames are stored as data in one entry */
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long_name = (char *) xrealloc(long_name, ar_entry->size);
fread(long_name, 1, ar_entry->size, in_file);
continue;
}
else {
/* The number after the '/' indicates the offset in the ar data section
(saved in variable long_name) that conatains the real filename */
const int long_name_offset = (int) atoi((char *) &raw_ar_header.name[1]);
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ar_entry->name = xmalloc(strlen(&long_name[long_name_offset]));
strcpy(ar_entry->name, &long_name[long_name_offset]);
}
}
else {
/* short filenames */
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ar_entry->name = xmalloc(16);
ar_entry->name = strncpy(ar_entry->name, raw_ar_header.name, 16);
}
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ar_entry->name[strcspn(ar_entry->name, " /")]='\0';
/* convert the rest of the now valid char header to its typed struct */
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parse_mode(raw_ar_header.mode, &ar_entry->mode);
ar_entry->mtime = atoi(raw_ar_header.date);
ar_entry->uid = atoi(raw_ar_header.uid);
ar_entry->gid = atoi(raw_ar_header.gid);
ar_entry->offset = ftell(in_file);
ar_entry->next = NULL;
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fseek(in_file, (off_t) ar_entry->size, SEEK_CUR);
ar_tmp = (ar_headers_t *) xcalloc(1, sizeof(ar_headers_t));
*ar_tmp = *ar_list;
*ar_list = *ar_entry;
free(ar_entry);
ar_list->next = ar_tmp;
}
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return(ar_list);
}