busybox/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@netconnect.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
*
* Last modified 9 September 2000
*/
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <time.h>
#include <utime.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <malloc.h>
#include "internal.h"
#define BLOCK_SIZE 60
#define PRESERVE_DATE 1 /* preserve original dates */
#define VERBOSE 2 /* be verbose */
#define DISPLAY 4 /* display contents */
#define EXT_TO_FILE 8 /* extract contents of archive */
#define EXT_TO_STDOUT 16 /* extract to stdout */
#define RECURSIVE 32
#define MAX_NAME_LENGTH 100
//#define BB_DECLARE_EXTERN
//#define bb_need_io_error
//#include "messages.c"
typedef struct rawArHeader { /* Byte Offset */
char name[16]; /* 0-15 */
char date[12]; /* 16-27 */
char uid[6], gid[6]; /* 28-39 */
char mode[8]; /* 40-47 */
char size[10]; /* 48-57 */
char fmag[2]; /* 58-59 */
} rawArHeader_t;
typedef struct headerL {
char name[MAX_NAME_LENGTH];
size_t size;
uid_t uid;
gid_t gid;
mode_t mode;
time_t mtime;
off_t offset;
struct headerL *next;
} headerL_t;
/*
* identify Ar header (magic) and set srcFd to first header entry
*/
static int checkArMagic(int srcFd)
{
char arMagic[8];
if (fullRead(srcFd, arMagic, 8) != 8)
return (FALSE);
if (strncmp(arMagic,"!<arch>",7) != 0)
return(FALSE);
return(TRUE);
}
/*
* read, convert and check the raw ar header
* srcFd should be pointing to the start of header prior to entry
* srcFd will be pointing at the start of data after successful exit
* if returns FALSE srcFd is reset to initial position
*/
static int readRawArHeader(int srcFd, headerL_t *header)
{
rawArHeader_t rawArHeader;
off_t initialOffset;
size_t nameLength;
initialOffset = lseek(srcFd, 0, SEEK_CUR);
if (fullRead(srcFd, (char *) &rawArHeader, 60) != 60) {
lseek(srcFd, initialOffset, SEEK_SET);
return(FALSE);
}
if ((rawArHeader.fmag[0]!='`') || (rawArHeader.fmag[1]!='\n')) {
lseek(srcFd, initialOffset, SEEK_SET);
return(FALSE);
}
strncpy(header->name, rawArHeader.name, 16);
nameLength=strcspn(header->name, " \\");
header->name[nameLength]='\0';
parse_mode(rawArHeader.mode, &header->mode);
header->mtime = atoi(rawArHeader.date);
header->uid = atoi(rawArHeader.uid);
header->gid = atoi(rawArHeader.gid);
header->size = (size_t) atoi(rawArHeader.size);
header->offset = initialOffset + (off_t) 60;
return(TRUE);
}
/*
* get, check and correct the converted header
*/
static int readArEntry(int srcFd, headerL_t *newEntry)
{
size_t nameLength;
if(readRawArHeader(srcFd, newEntry)==FALSE)
return(FALSE);
nameLength = strcspn(newEntry->name, "/");
/* handle GNU style short filenames, strip trailing '/' */
if (nameLength > 0)
newEntry->name[nameLength]='\0';
/* handle GNU style long filenames */
if (nameLength == 0) {
/* escape from recursive call */
if (newEntry->name[1]=='0')
return(TRUE);
/* the data section contains the real filename */
if (newEntry->name[1]=='/') {
char tempName[MAX_NAME_LENGTH];
if (newEntry->size > MAX_NAME_LENGTH)
newEntry->size = MAX_NAME_LENGTH;
fullRead(srcFd, tempName, newEntry->size);
tempName[newEntry->size-3]='\0';
/* read the second header for this entry */
/* be carefull, this is recursive */
if (readArEntry(srcFd, newEntry)==FALSE)
return(FALSE);
if ((newEntry->name[0]='/') && (newEntry->name[1]='0'))
strcpy(newEntry->name, tempName);
else {
errorMsg("Invalid long filename\n");
return(FALSE);
}
}
}
return(TRUE);
}
/*
* return the headerL_t struct for the specified filename
*/
static headerL_t *getHeaders(int srcFd, headerL_t *head, int funct)
{
headerL_t *list;
list = (headerL_t *) malloc(sizeof(headerL_t));
if (checkArMagic(srcFd)==TRUE) {
while(readArEntry(srcFd, list) == TRUE) {
list->next = (headerL_t *) malloc(sizeof(headerL_t));
*list->next = *head;
*head = *list;
/* recursive check for sub-archives */
if ((funct & RECURSIVE) == RECURSIVE)
head = getHeaders(srcFd, head, funct);
lseek(srcFd, head->offset + head->size, SEEK_SET);
}
}
return(head);
}
/*
* find an entry in the linked list matching the filename
*/
static headerL_t *findEntry(headerL_t *head, const char *filename)
{
while(head->next != NULL) {
if (strcmp(filename, head->name)==0)
return(head);
head=head->next;
}
return(NULL);
}
/*
* populate linked list with all ar file entries and offset
*/
static int displayEntry(headerL_t *head, int funct)
{
if ((funct & VERBOSE) == VERBOSE) {
printf("%s %d/%d %8d %s ", modeString(head->mode), head->uid, head->gid, head->size, timeString(head->mtime));
}
printf("%s\n", head->name);
head = head->next;
return(TRUE);
}
static int extractAr(int srcFd, int dstFd, headerL_t *file)
{
lseek(srcFd, file->offset, SEEK_SET);
if (copySubFile(srcFd, dstFd, (size_t) file->size) == TRUE)
return(TRUE);
return(FALSE);
}
extern int ar_main(int argc, char **argv)
{
int funct = 0, opt=0;
int srcFd=0, dstFd=0;
headerL_t *header, *entry, *extractList;
while ((opt = getopt(argc, argv, "ovtpxR")) != -1) {
switch (opt) {
case 'o':
funct = funct | PRESERVE_DATE;
break;
case 'v':
funct = funct | VERBOSE;
break;
case 't':
funct = funct | DISPLAY;
break;
case 'x':
funct = funct | EXT_TO_FILE;
break;
case 'p':
funct = funct | EXT_TO_STDOUT;
break;
case 'R':
funct = funct | RECURSIVE;
break;
default:
usage(ar_usage);
}
}
/* check the src filename was specified */
if (optind == argc) {
usage(ar_usage);
return(FALSE);
}
if ( (srcFd = open(argv[optind], O_RDONLY)) < 0) {
errorMsg("Cannot read %s\n", optarg);
return (FALSE);
}
optind++;
entry = (headerL_t *) malloc(sizeof(headerL_t));
header = (headerL_t *) malloc(sizeof(headerL_t));
extractList = (headerL_t *) malloc(sizeof(headerL_t));
header = getHeaders(srcFd, header, funct);
/* find files to extract or display */
if (optind<argc) {
/* only handle specified files */
while(optind < argc) {
if ( (entry = findEntry(header, argv[optind])) != NULL) {
entry->next = (headerL_t *) malloc(sizeof(headerL_t));
*entry->next = *extractList;
*extractList = *entry;
}
optind++;
}
}
else
/* extract everything */
extractList = header;
while(extractList->next != NULL) {
if ( (funct & EXT_TO_FILE) == EXT_TO_FILE) {
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dstFd = open(extractList->name, O_WRONLY | O_CREAT, extractList->mode);
extractAr(srcFd, dstFd, extractList);
}
if ( (funct & EXT_TO_STDOUT) == EXT_TO_STDOUT)
extractAr(srcFd, fileno(stdout), extractList);
if ( (funct & DISPLAY) == DISPLAY)
displayEntry(extractList, funct);
extractList=extractList->next;
}
return (TRUE);
}