busybox/archival/ar.c

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/* vi: set sw=4 ts=4: */
/*
* Mini ar implementation for busybox
*
* Copyright (C) 2000 by Glenn McGrath
* Written by Glenn McGrath <bug1@optushome.com.au> 1 June 2000
*
* Based in part on BusyBox tar, Debian dpkg-deb and GNU ar.
*
* 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
*
*/
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>
#include <unistd.h>
#include "busybox.h"
typedef struct ar_headers_s {
char *name;
size_t size;
uid_t uid;
gid_t gid;
mode_t mode;
time_t mtime;
off_t offset;
struct ar_headers_s *next;
} ar_headers_t;
/*
* return the headerL_t struct for the filename descriptor
*/
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extern ar_headers_t get_ar_headers(int srcFd)
{
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;
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raw_ar_header_t raw_ar_header;
ar_headers_t *head, *entry;
char ar_magic[8];
char *long_name=NULL;
head = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
entry = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
/* check ar magic */
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if (full_read(srcFd, ar_magic, 8) != 8) {
error_msg_and_die("cannot read magic");
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}
if (strncmp(ar_magic,"!<arch>",7) != 0) {
error_msg_and_die("invalid magic");
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}
while (full_read(srcFd, (char *) &raw_ar_header, 60)==60) {
/* check the end of header markers are valid */
if ((raw_ar_header.fmag[0]!='`') || (raw_ar_header.fmag[1]!='\n')) {
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char newline;
if (raw_ar_header.fmag[1]!='`') {
break;
}
/* some version of ar, have an extra '\n' after each entry */
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read(srcFd, &newline, 1);
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 */
}
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 */
long_name = (char *) xrealloc(long_name, entry->size);
full_read(srcFd, long_name, entry->size);
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]);
entry->name = xmalloc(strlen(&long_name[long_name_offset]));
strcpy(entry->name, &long_name[long_name_offset]);
}
}
else {
/* short filenames */
entry->name = xmalloc(16);
strncpy(entry->name, raw_ar_header.name, 16);
}
entry->name[strcspn(entry->name, " /")]='\0';
/* convert the rest of the now valid char header to its typed struct */
parse_mode(raw_ar_header.mode, &entry->mode);
entry->mtime = atoi(raw_ar_header.date);
entry->uid = atoi(raw_ar_header.uid);
entry->gid = atoi(raw_ar_header.gid);
entry->offset = lseek(srcFd, 0, SEEK_CUR);
/* add this entries header to our combined list */
entry->next = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
*entry->next = *head;
*head = *entry;
lseek(srcFd, (off_t) entry->size, SEEK_CUR);
}
return(*head);
}
extern int ar_main(int argc, char **argv)
{
const int preserve_date = 1; /* preserve original dates */
const int verbose = 2; /* be verbose */
const int display = 4; /* display contents */
const int extract_to_file = 8; /* extract contents of archive */
const int extract_to_stdout = 16; /* extract to stdout */
int funct = 0, opt=0;
int srcFd=0, dstFd=0;
ar_headers_t head, *extract_list=NULL;
extract_list = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
while ((opt = getopt(argc, argv, "ovtpx")) != -1) {
switch (opt) {
case 'o':
funct |= preserve_date;
break;
case 'v':
funct |= verbose;
break;
case 't':
funct |= display;
break;
case 'p':
funct |= extract_to_stdout;
break;
case 'x':
funct |= extract_to_file;
break;
default:
show_usage();
}
}
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/* check the src filename was specified */
if (optind == argc)
show_usage();
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if ( (srcFd = open(argv[optind], O_RDONLY)) < 0)
error_msg_and_die("Cannot read %s", argv[optind]);
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optind++;
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head = get_ar_headers(srcFd);
/* find files to extract or display */
/* search through argv and build extract list */
for (;optind<argc; optind++) {
ar_headers_t *ar_entry;
ar_entry = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
ar_entry = &head;
while (ar_entry->next != NULL) {
if (strcmp(argv[optind], ar_entry->name) == 0) {
ar_headers_t *tmp;
tmp = (ar_headers_t *) xmalloc(sizeof(ar_headers_t));
*tmp = *extract_list;
*extract_list = *ar_entry;
extract_list->next = tmp;
break;
}
ar_entry=ar_entry->next;
}
}
/* if individual files not found extract all files */
if (extract_list->next==NULL) {
extract_list = &head;
}
/* find files to extract or display */
while (extract_list->next != NULL) {
if (funct & extract_to_file) {
dstFd = open(extract_list->name, O_WRONLY | O_CREAT, extract_list->mode);
}
else if (funct & extract_to_stdout) {
dstFd = fileno(stdout);
}
if ((funct & extract_to_file) || (funct & extract_to_stdout)) {
lseek(srcFd, extract_list->offset, SEEK_SET);
copy_file_chunk(srcFd, dstFd, (size_t) extract_list->size);
}
if (funct & verbose) {
printf("%s %d/%d %8d %s ", mode_string(extract_list->mode),
extract_list->uid, extract_list->gid,
extract_list->size, time_string(extract_list->mtime));
}
if ((funct & display) || (funct & verbose)){
printf("%s\n", extract_list->name);
}
extract_list=extract_list->next;
}
return EXIT_SUCCESS;
}