/* FIXME:
* 1. Symbolic links are not created.
* 2. Untar_FromMemory has printfs.
* 3. Untar_FromMemory uses FILE *fp.
* 4. How to determine end of archive?
*
* Written by: Jake Janovetz <janovetz@tempest.ece.uiuc.edu>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* $Id$
*/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "untar.h"
/**************************************************************************
* TAR file format:
*
* Offset Length Contents
* 0 100 bytes File name ('\0' terminated, 99 maxmum length)
* 100 8 bytes File mode (in octal ascii)
* 108 8 bytes User ID (in octal ascii)
* 116 8 bytes Group ID (in octal ascii)
* 124 12 bytes File size (s) (in octal ascii)
* 136 12 bytes Modify time (in octal ascii)
* 148 8 bytes Header checksum (in octal ascii)
* 156 1 bytes Link flag
* 157 100 bytes Linkname ('\0' terminated, 99 maxmum length)
* 257 8 bytes Magic ("ustar \0")
* 265 32 bytes User name ('\0' terminated, 31 maxmum length)
* 297 32 bytes Group name ('\0' terminated, 31 maxmum length)
* 329 8 bytes Major device ID (in octal ascii)
* 337 8 bytes Minor device ID (in octal ascii)
* 345 167 bytes Padding
* 512 (s+p)bytes File contents (s+p) := (((s) + 511) & ~511),
* round up to 512 bytes
*
* Checksum:
* int i, sum;
* char* header = tar_header_pointer;
* sum = 0;
* for(i = 0; i < 512; i++)
* sum += 0xFF & header[i];
*************************************************************************/
#define LF_OLDNORMAL '\0' /* Normal disk file, Unix compatible */
#define LF_NORMAL '0' /* Normal disk file */
#define LF_LINK '1' /* Link to previously dumped file */
#define LF_SYMLINK '2' /* Symbolic link */
#define LF_CHR '3' /* Character special file */
#define LF_BLK '4' /* Block special file */
#define LF_DIR '5' /* Directory */
#define LF_FIFO '6' /* FIFO special file */
#define LF_CONFIG '7' /* Contiguous file */
#define MAX_NAME_FIELD_SIZE 99
#define MIN(a,b) ((a)>(b)?(b):(a))
/**************************************************************************
* This converts octal ASCII number representations into an
* unsigned long. Only support 32-bit numbers for now.
*************************************************************************/
static unsigned long
octal2ulong(char *octascii, int len)
{
int i;
unsigned long num;
unsigned long mult;
num = 0;
mult = 1;
for (i=len-1; i>=0; i--)
{
if ((octascii[i] < '0') || (octascii[i] > '9'))
{
continue;
}
num += mult*((unsigned long)(octascii[i] - '0'));
mult *= 8;
}
return(num);
}
/**************************************************************************
* Function: Untar_FromMemory *
**************************************************************************
* Description: *
* *
* This is a simple subroutine used to rip links, directories, and *
* files out of a block of memory. *
* *
* *
* Inputs: *
* *
* unsigned char *tar_buf - Pointer to TAR buffer. *
* unsigned long size - Length of TAR buffer. *
* *
* *
* Output: *
* *
* int - UNTAR_SUCCESSFUL (0) on successful completion. *
* UNTAR_INVALID_CHECKSUM for an invalid header checksum. *
* UNTAR_INVALID_HEADER for an invalid header. *
* *
**************************************************************************
* Change History: *
* 12/30/1998 - Creation (JWJ) *
*************************************************************************/
int
Untar_FromMemory(unsigned char *tar_buf, unsigned long size)
{
FILE *fp;
char *bufr;
size_t n;
char fname[100];
char linkname[100];
int sum;
int hdr_chksum;
int retval;
unsigned long ptr;
unsigned long i;
unsigned long nblocks;
unsigned long file_size;
unsigned char linkflag;
ptr = 0;
while (1)
{
if (ptr + 512 > size)
{
retval = UNTAR_SUCCESSFUL;
break;
}
/* Read the header */
bufr = &tar_buf[ptr];
ptr += 512;
if (strncmp(&bufr[257], "ustar ", 7))
{
retval = UNTAR_SUCCESSFUL;
break;
}
strncpy(fname, bufr, MAX_NAME_FIELD_SIZE);
fname[MAX_NAME_FIELD_SIZE] = '\0';
linkflag = bufr[156];
file_size = octal2ulong(&bufr[124], 12);
/******************************************************************
* Compute the TAR checksum and check with the value in
* the archive. The checksum is computed over the entire
* header, but the checksum field is substituted with blanks.
******************************************************************/
hdr_chksum = (int)octal2ulong(&bufr[148], 8);
sum = 0;
for (i=0; i<512; i++)
{
if ((i >= 148) && (i < 156))
{
sum += 0xff & ' ';
}
else
{
sum += 0xff & bufr[i];
}
}
if (sum != hdr_chksum)
{
retval = UNTAR_INVALID_CHECKSUM;
break;
}
/******************************************************************
* We've decoded the header, now figure out what it contains and
* do something with it.
*****************************************************************/
if (linkflag == LF_SYMLINK)
{
strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE);
linkname[MAX_NAME_FIELD_SIZE] = '\0';
/* symlink(fname, linkname); */
}
else if (linkflag == LF_NORMAL)
{
nblocks = (((file_size) + 511) & ~511) / 512;
if ((fp = fopen(fname, "w")) == NULL)
{
printf("Untar failed to create file %s\n", fname);
ptr += 512 * nblocks;
}
else
{
unsigned long sizeToGo = file_size;
unsigned long len;
/***************************************************************
* Read out the data. There are nblocks of data where nblocks
* is the file_size rounded to the nearest 512-byte boundary.
**************************************************************/
for (i=0; i<nblocks; i++)
{
len = ((sizeToGo < 512L)?(sizeToGo):(512L));
n = fwrite(&tar_buf[ptr], 1, len, fp);
if (n != len)
{
printf("Error during write\n");
break;
}
ptr += 512;
sizeToGo -= n;
}
fclose(fp);
}
}
else if (linkflag == LF_DIR)
{
mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO);
}
}
return(retval);
}
/**************************************************************************
* Function: Untar_FromFile *
**************************************************************************
* Description: *
* *
* This is a simple subroutine used to rip links, directories, and *
* files out of a TAR file. *
* *
* *
* Inputs: *
* *
* char *tar_name - TAR filename. *
* *
* *
* Output: *
* *
* int - UNTAR_SUCCESSFUL (0) on successful completion. *
* UNTAR_INVALID_CHECKSUM for an invalid header checksum. *
* UNTAR_INVALID_HEADER for an invalid header. *
* *
**************************************************************************
* Change History: *
* 12/30/1998 - Creation (JWJ) *
*************************************************************************/
int
Untar_FromFile(char *tar_name)
{
int fd;
char *bufr;
size_t n;
char fname[100];
char linkname[100];
int sum;
int hdr_chksum;
int retval;
unsigned long i;
unsigned long nblocks;
unsigned long size;
unsigned char linkflag;
retval = UNTAR_SUCCESSFUL;
bufr = (char *)malloc(512);
if (bufr == NULL)
{
return(UNTAR_FAIL);
}
fd = open(tar_name, O_RDONLY);
while (1)
{
/* Read the header */
/* If the header read fails, we just consider it the end
of the tarfile. */
if ((n = read(fd, bufr, 512)) != 512)
{
break;
}
if (strncmp(&bufr[257], "ustar ", 7))
{
break;
}
strncpy(fname, bufr, MAX_NAME_FIELD_SIZE);
fname[MAX_NAME_FIELD_SIZE] = '\0';
linkflag = bufr[156];
size = octal2ulong(&bufr[124], 12);
/******************************************************************
* Compute the TAR checksum and check with the value in
* the archive. The checksum is computed over the entire
* header, but the checksum field is substituted with blanks.
******************************************************************/
hdr_chksum = (int)octal2ulong(&bufr[148], 8);
sum = 0;
for (i=0; i<512; i++)
{
if ((i >= 148) && (i < 156))
{
sum += 0xff & ' ';
}
else
{
sum += 0xff & bufr[i];
}
}
if (sum != hdr_chksum)
{
retval = UNTAR_INVALID_CHECKSUM;
break;
}
/******************************************************************
* We've decoded the header, now figure out what it contains and
* do something with it.
*****************************************************************/
if (linkflag == LF_SYMLINK)
{
strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE);
linkname[MAX_NAME_FIELD_SIZE] = '\0';
}
else if (linkflag == LF_NORMAL)
{
int out_fd;
/******************************************************************
* Read out the data. There are nblocks of data where nblocks
* is the size rounded to the nearest 512-byte boundary.
*****************************************************************/
nblocks = (((size) + 511) & ~511) / 512;
if ((out_fd = creat(fname, 0644)) == -1)
{
for (i=0; i<nblocks; i++)
{
n = read(fd, bufr, 512);
}
}
else
{
for (i=0; i<nblocks; i++)
{
n = read(fd, bufr, 512);
n = MIN(n, size - i*512);
write(out_fd, bufr, n);
}
close(out_fd);
}
}
else if (linkflag == LF_DIR)
{
mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO);
}
}
free(bufr);
close(fd);
return(retval);
}
