forked from Imagelibrary/rtems
9394aa5ed7
The problem exists for both RTEMS untar implementations and their variants: Untar_FromMemory(), Untar_FromFile() and rtems_tarfs_load(). If filesystem object already exists at extracted directory path then if it is directory, creation is ignored. Attempt to delete/unlink object and make directory is tried for other cases. This simple approach problem reported in ticket fixes #2413. Behavior follows GNU tar and BSD tar practice for directories but much more work is required to achieve full semantics of the full featured tar implementation still.
380 lines
9.3 KiB
C
380 lines
9.3 KiB
C
/**
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* @file
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* @brief Untar an Image
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* @ingroup libmisc_untar_img Untar Image
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* FIXME:
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* 1. Symbolic links are not created.
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* 2. Untar_FromMemory uses FILE *fp.
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* 3. How to determine end of archive?
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*/
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/*
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* Written by: Jake Janovetz <janovetz@tempest.ece.uiuc.edu>
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* The license and distribution terms for this file may be
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* found in the file LICENSE in this distribution or at
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* http://www.rtems.org/license/LICENSE.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <sys/param.h>
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#include <stdio.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <rtems/untar.h>
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#include <rtems/bspIo.h>
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/*
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* TAR file format:
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* Offset Length Contents
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* 0 100 bytes File name ('\0' terminated, 99 maxmum length)
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* 100 8 bytes File mode (in octal ascii)
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* 108 8 bytes User ID (in octal ascii)
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* 116 8 bytes Group ID (in octal ascii)
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* 124 12 bytes File size (s) (in octal ascii)
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* 136 12 bytes Modify time (in octal ascii)
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* 148 8 bytes Header checksum (in octal ascii)
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* 156 1 bytes Link flag
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* 157 100 bytes Linkname ('\0' terminated, 99 maxmum length)
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* 257 8 bytes Magic PAX ("ustar\0" + 2 bytes padding)
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* 257 8 bytes Magic GNU tar ("ustar \0")
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* 265 32 bytes User name ('\0' terminated, 31 maxmum length)
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* 297 32 bytes Group name ('\0' terminated, 31 maxmum length)
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* 329 8 bytes Major device ID (in octal ascii)
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* 337 8 bytes Minor device ID (in octal ascii)
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* 345 155 bytes Prefix
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* 512 (s+p)bytes File contents (s+p) := (((s) + 511) & ~511),
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* round up to 512 bytes
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*
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* Checksum:
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* int i, sum;
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* char* header = tar_header_pointer;
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* sum = 0;
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* for(i = 0; i < 512; i++)
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* sum += 0xFF & header[i];
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*/
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#define MAX_NAME_FIELD_SIZE 99
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/*
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* This converts octal ASCII number representations into an
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* unsigned long. Only support 32-bit numbers for now.
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*/
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unsigned long
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_rtems_octal2ulong(
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const char *octascii,
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size_t len
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)
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{
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size_t i;
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unsigned long num;
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num = 0;
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for (i=0; i < len; i++) {
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if ((octascii[i] < '0') || (octascii[i] > '9')) {
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continue;
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}
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num = num * 8 + ((unsigned long)(octascii[i] - '0'));
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}
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return(num);
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}
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/*
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* Function: Untar_FromMemory
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*
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* Description:
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*
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* This is a simple subroutine used to rip links, directories, and
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* files out of a block of memory.
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*
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*
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* Inputs:
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*
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* void * tar_buf - Pointer to TAR buffer.
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* size_t size - Length of TAR buffer.
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*
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*
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* Output:
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*
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* int - UNTAR_SUCCESSFUL (0) on successful completion.
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* UNTAR_INVALID_CHECKSUM for an invalid header checksum.
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* UNTAR_INVALID_HEADER for an invalid header.
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*
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*/
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int
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Untar_FromMemory(
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void *tar_buf,
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size_t size
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)
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{
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FILE *fp;
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const char *tar_ptr = (const char *)tar_buf;
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const char *bufr;
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size_t n;
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char fname[100];
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char linkname[100];
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int sum;
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int hdr_chksum;
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int retval;
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unsigned long ptr;
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unsigned long i;
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unsigned long nblocks;
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unsigned long file_size;
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unsigned char linkflag;
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ptr = 0;
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while (1) {
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if (ptr + 512 > size) {
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retval = UNTAR_SUCCESSFUL;
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break;
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}
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/* Read the header */
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bufr = &tar_ptr[ptr];
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ptr += 512;
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if (strncmp(&bufr[257], "ustar", 5)) {
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retval = UNTAR_SUCCESSFUL;
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break;
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}
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strncpy(fname, bufr, MAX_NAME_FIELD_SIZE);
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fname[MAX_NAME_FIELD_SIZE] = '\0';
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linkflag = bufr[156];
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file_size = _rtems_octal2ulong(&bufr[124], 12);
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/*
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* Compute the TAR checksum and check with the value in
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* the archive. The checksum is computed over the entire
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* header, but the checksum field is substituted with blanks.
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*/
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hdr_chksum = _rtems_octal2ulong(&bufr[148], 8);
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sum = _rtems_tar_header_checksum(bufr);
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if (sum != hdr_chksum) {
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retval = UNTAR_INVALID_CHECKSUM;
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break;
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}
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/*
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* We've decoded the header, now figure out what it contains and
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* do something with it.
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*/
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if (linkflag == SYMTYPE) {
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strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE);
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linkname[MAX_NAME_FIELD_SIZE] = '\0';
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symlink(linkname, fname);
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} else if (linkflag == REGTYPE) {
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nblocks = (((file_size) + 511) & ~511) / 512;
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if ((fp = fopen(fname, "w")) == NULL) {
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printk("Untar: failed to create file %s\n", fname);
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ptr += 512 * nblocks;
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} else {
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unsigned long sizeToGo = file_size;
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size_t len;
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/*
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* Read out the data. There are nblocks of data where nblocks
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* is the file_size rounded to the nearest 512-byte boundary.
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*/
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for (i=0; i<nblocks; i++) {
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len = ((sizeToGo < 512L)?(sizeToGo):(512L));
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n = fwrite(&tar_ptr[ptr], 1, len, fp);
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if (n != len) {
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printk("untar: Error during write\n");
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retval = UNTAR_FAIL;
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break;
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}
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ptr += 512;
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sizeToGo -= n;
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}
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fclose(fp);
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}
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} else if (linkflag == DIRTYPE) {
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if ( mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO) != 0 ) {
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if (errno == EEXIST) {
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struct stat stat_buf;
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if ( stat(fname, &stat_buf) == 0 ) {
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if ( S_ISDIR(stat_buf.st_mode) ) {
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continue;
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} else {
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if ( unlink(fname) != -1 ) {
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if ( mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO) == 0 )
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continue;
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}
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}
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}
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}
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printk("Untar: failed to create directory %s\n", fname);
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retval = UNTAR_FAIL;
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break;
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}
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}
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}
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return(retval);
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}
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/*
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* Function: Untar_FromFile
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*
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* Description:
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*
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* This is a simple subroutine used to rip links, directories, and
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* files out of a TAR file.
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*
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* Inputs:
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*
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* const char *tar_name - TAR filename.
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*
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* Output:
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*
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* int - UNTAR_SUCCESSFUL (0) on successful completion.
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* UNTAR_INVALID_CHECKSUM for an invalid header checksum.
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* UNTAR_INVALID_HEADER for an invalid header.
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*/
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int
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Untar_FromFile(
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const char *tar_name
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)
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{
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int fd;
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char *bufr;
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ssize_t n;
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char fname[100];
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char linkname[100];
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int sum;
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int hdr_chksum;
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int retval;
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unsigned long i;
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unsigned long nblocks;
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unsigned long size;
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unsigned char linkflag;
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retval = UNTAR_SUCCESSFUL;
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if ((fd = open(tar_name, O_RDONLY)) < 0) {
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return UNTAR_FAIL;
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}
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bufr = (char *)malloc(512);
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if (bufr == NULL) {
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close(fd);
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return(UNTAR_FAIL);
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}
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while (1) {
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/* Read the header */
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/* If the header read fails, we just consider it the end of the tarfile. */
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if ((n = read(fd, bufr, 512)) != 512) {
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break;
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}
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if (strncmp(&bufr[257], "ustar", 5)) {
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break;
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}
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strncpy(fname, bufr, MAX_NAME_FIELD_SIZE);
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fname[MAX_NAME_FIELD_SIZE] = '\0';
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linkflag = bufr[156];
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size = _rtems_octal2ulong(&bufr[124], 12);
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/*
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* Compute the TAR checksum and check with the value in
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* the archive. The checksum is computed over the entire
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* header, but the checksum field is substituted with blanks.
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*/
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hdr_chksum = _rtems_octal2ulong(&bufr[148], 8);
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sum = _rtems_tar_header_checksum(bufr);
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if (sum != hdr_chksum) {
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retval = UNTAR_INVALID_CHECKSUM;
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break;
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}
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/*
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* We've decoded the header, now figure out what it contains and
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* do something with it.
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*/
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if (linkflag == SYMTYPE) {
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strncpy(linkname, &bufr[157], MAX_NAME_FIELD_SIZE);
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linkname[MAX_NAME_FIELD_SIZE] = '\0';
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symlink(linkname,fname);
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} else if (linkflag == REGTYPE) {
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int out_fd;
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/*
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* Read out the data. There are nblocks of data where nblocks
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* is the size rounded to the nearest 512-byte boundary.
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*/
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nblocks = (((size) + 511) & ~511) / 512;
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if ((out_fd = creat(fname, 0644)) == -1) {
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(void) lseek(fd, SEEK_CUR, 512 * nblocks);
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} else {
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for (i=0; i<nblocks; i++) {
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n = read(fd, bufr, 512);
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n = MIN(n, size - i*512);
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(void) write(out_fd, bufr, n);
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}
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close(out_fd);
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}
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} else if (linkflag == DIRTYPE) {
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if ( mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO) != 0 ) {
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if (errno == EEXIST) {
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struct stat stat_buf;
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if ( stat(fname, &stat_buf) == 0 ) {
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if ( S_ISDIR(stat_buf.st_mode) ) {
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continue;
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} else {
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if ( unlink(fname) != -1 ) {
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if ( mkdir(fname, S_IRWXU | S_IRWXG | S_IRWXO) == 0 )
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continue;
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}
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}
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}
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}
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}
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}
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}
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free(bufr);
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close(fd);
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return(retval);
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}
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/*
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* Compute the TAR checksum and check with the value in
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* the archive. The checksum is computed over the entire
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* header, but the checksum field is substituted with blanks.
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*/
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int
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_rtems_tar_header_checksum(
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const char *bufr
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)
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{
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int i, sum;
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sum = 0;
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for (i=0; i<512; i++) {
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if ((i >= 148) && (i < 156))
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sum += 0xff & ' ';
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else
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sum += 0xff & bufr[i];
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}
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return(sum);
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}
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