busybox/ar.c
Mark Whitley 4758368505 Fixed the comments to match the code and renamed the function to a (hopefully)
more descriptive name, and as per the style guide.
2000-12-05 20:03:17 +00:00

392 lines
11 KiB
C

/* 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 20 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 "busybox.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"
//#define BB_AR_EXPERIMENTAL_UNTAR
#if defined BB_AR_EXPERIMENTAL_UNTAR
typedef struct rawTarHeader {
char name[100]; /* 0-99 */
char mode[8]; /* 100-107 */
char uid[8]; /* 108-115 */
char gid[8]; /* 116-123 */
char size[12]; /* 124-135 */
char mtime[12]; /* 136-147 */
char chksum[8]; /* 148-155 */
char typeflag; /* 156-156 */
char linkname[100]; /* 157-256 */
char magic[6]; /* 257-262 */
char version[2]; /* 263-264 */
char uname[32]; /* 265-296 */
char gname[32]; /* 297-328 */
char devmajor[8]; /* 329-336 */
char devminor[8]; /* 337-344 */
char prefix[155]; /* 345-499 */
char padding[12]; /* 500-512 */
} rawTarHeader_t;
#endif
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;
#if defined BB_AR_EXPERIMENTAL_UNTAR
/*
* identify Tar header (magic field) and reset srcFd to entry position
*/
static int checkTarMagic(int srcFd)
{
off_t headerStart;
char magic[6];
headerStart = lseek(srcFd, 0, SEEK_CUR);
lseek(srcFd, (off_t) 257, SEEK_CUR);
fullRead(srcFd, magic, 6);
lseek(srcFd, headerStart, SEEK_SET);
if (strncmp(magic, "ustar", 5)!=0)
return(FALSE);
return(TRUE);
}
static int readTarHeader(int srcFd, headerL_t *current)
{
rawTarHeader_t rawTarHeader;
unsigned char *temp = (unsigned char *) &rawTarHeader;
long sum = 0;
int i;
off_t initialOffset;
initialOffset = lseek(srcFd, 0, SEEK_CUR);
if (fullRead(srcFd, (char *) &rawTarHeader, 512) != 512) {
lseek(srcFd, initialOffset, SEEK_SET);
return(FALSE);
}
for (i = 0; i < 148 ; i++)
sum += temp[i];
sum += ' ' * 8;
for (i = 156; i < 512 ; i++)
sum += temp[i];
if (sum!= strtol(rawTarHeader.chksum, NULL, 8))
return(FALSE);
sscanf(rawTarHeader.name, "%s", current->name);
current->size = strtol(rawTarHeader.size, NULL, 8);
current->uid = strtol(rawTarHeader.uid, NULL, 8);
current->gid = strtol(rawTarHeader.gid, NULL, 8);
current->mode = strtol(rawTarHeader.mode, NULL, 8);
current->mtime = strtol(rawTarHeader.mtime, NULL, 8);
current->offset = lseek(srcFd, 0 , SEEK_CUR);
current->next = (headerL_t *) xmalloc(sizeof(headerL_t));
current = current->next;
return(TRUE);
}
#endif
/*
* identify Ar header (magic) and reset srcFd to entry position
*/
static int checkArMagic(int srcFd)
{
off_t headerStart;
char arMagic[8];
headerStart = lseek(srcFd, 0, SEEK_CUR);
if (fullRead(srcFd, arMagic, 8) != 8) {
errorMsg("fatal error\n");
return (FALSE);
}
lseek(srcFd, headerStart, SEEK_SET);
if (strncmp(arMagic,"!<arch>",7) != 0)
return(FALSE);
return(TRUE);
}
/*
* get, check and correct the converted header
*/
static int readArEntry(int srcFd, headerL_t *entry)
{
size_t nameLength;
rawArHeader_t rawArHeader;
off_t initialOffset;
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(entry->name, rawArHeader.name, 16);
nameLength=strcspn(entry->name, " \\");
entry->name[nameLength]='\0';
parse_mode(rawArHeader.mode, &entry->mode);
entry->mtime = atoi(rawArHeader.date);
entry->uid = atoi(rawArHeader.uid);
entry->gid = atoi(rawArHeader.gid);
entry->size = (size_t) atoi(rawArHeader.size);
entry->offset = initialOffset + (off_t) 60;
nameLength = strcspn(entry->name, "/");
/* handle GNU style short filenames, strip trailing '/' */
if (nameLength > 0)
entry->name[nameLength]='\0';
/* handle GNU style long filenames */
if (nameLength == 0) {
/* escape from recursive call */
if (entry->name[1]=='0')
return(TRUE);
/* the data section contains the real filename */
if (entry->name[1]=='/') {
char tempName[MAX_NAME_LENGTH];
if (entry->size > MAX_NAME_LENGTH)
entry->size = MAX_NAME_LENGTH;
fullRead(srcFd, tempName, entry->size);
tempName[entry->size-3]='\0';
/* read the second header for this entry */
/* be carefull, this is recursive */
if (readArEntry(srcFd, entry)==FALSE)
return(FALSE);
if ((entry->name[0]='/') && (entry->name[1]='0'))
strcpy(entry->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)
{
#if defined BB_AR_EXPERIMENTAL_UNTAR
int tar=FALSE;
#endif
int ar=FALSE;
headerL_t *list;
off_t initialOffset;
list = (headerL_t *) xmalloc(sizeof(headerL_t));
initialOffset=lseek(srcFd, 0, SEEK_CUR);
if (checkArMagic(srcFd)==TRUE)
ar=TRUE;
#if defined BB_AR_EXPERIMENTAL_UNTAR
if (checkTarMagic(srcFd)==TRUE)
tar=TRUE;
if (tar==TRUE) {
while(readTarHeader(srcFd, list)==TRUE) {
off_t tarOffset;
list->next = (headerL_t *) xmalloc(sizeof(headerL_t));
*list->next = *head;
*head = *list;
/* recursive check for sub-archives */
if ((funct & RECURSIVE) == RECURSIVE)
head = getHeaders(srcFd, head, funct);
tarOffset = (off_t) head->size/512;
if ( head->size % 512 > 0)
tarOffset++;
tarOffset=tarOffset*512;
lseek(srcFd, head->offset + tarOffset, SEEK_SET);
}
}
#endif
if (ar==TRUE) {
lseek(srcFd, 8, SEEK_CUR);
while(1) {
if (readArEntry(srcFd, list) == FALSE) {
lseek(srcFd, ++initialOffset, SEEK_CUR);
if (readArEntry(srcFd, list) == FALSE)
return(head);
}
list->next = (headerL_t *) xmalloc(sizeof(headerL_t));
*list->next = *head;
*head = *list;
/* recursive check for sub-archives */
if (funct & 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);
}
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 |= PRESERVE_DATE;
break;
case 'v':
funct |= VERBOSE;
break;
case 't':
funct |= DISPLAY;
break;
case 'x':
funct |= EXT_TO_FILE;
break;
case 'p':
funct |= EXT_TO_STDOUT;
break;
case 'R':
funct |= RECURSIVE;
break;
default:
usage(ar_usage);
}
}
/* check the src filename was specified */
if (optind == argc)
usage(ar_usage);
if ( (srcFd = open(argv[optind], O_RDONLY)) < 0)
fatalError("Cannot read %s\n", argv[optind]);
optind++;
entry = (headerL_t *) xmalloc(sizeof(headerL_t));
header = (headerL_t *) xmalloc(sizeof(headerL_t));
extractList = (headerL_t *) xmalloc(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 *) xmalloc(sizeof(headerL_t));
*entry->next = *extractList;
*extractList = *entry;
}
optind++;
}
}
else
extractList = header;
while(extractList->next != NULL) {
if (funct & EXT_TO_FILE) {
if (isDirectory(extractList->name, TRUE, NULL)==FALSE)
createPath(extractList->name, 0666);
dstFd = open(extractList->name, O_WRONLY | O_CREAT, extractList->mode);
lseek(srcFd, extractList->offset, SEEK_SET);
copy_file_chunk(srcFd, dstFd, (size_t) extractList->size);
}
if (funct & EXT_TO_STDOUT) {
lseek(srcFd, extractList->offset, SEEK_SET);
copy_file_chunk(srcFd, fileno(stdout), (size_t) extractList->size);
}
if ( (funct & DISPLAY) || (funct & VERBOSE)) {
if (funct & VERBOSE)
printf("%s %d/%d %8d %s ", modeString(extractList->mode),
extractList->uid, extractList->gid,
extractList->size, timeString(extractList->mtime));
printf("%s\n", extractList->name);
}
extractList=extractList->next;
}
return EXIT_SUCCESS;
}