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/* abuild-tar.c - A TAR mangling utility for .APK packages
*
* Copyright (C) 2009 Timo Teräs <timo.teras@iki.fi>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation. See http://www.gnu.org/ for details.
*/
#include <stdio.h>
#include <fcntl.h>
#include <getopt.h>
#include <unistd.h>
#include <string.h>
#include <openssl/evp.h>
#ifndef VERSION
#define VERSION ""
#endif
struct tar_header {
/* ustar header, Posix 1003.1 */
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[8]; /* 257-264 */
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 */
};
#define GET_OCTAL(s) get_octal(s, sizeof(s))
#define PUT_OCTAL(s,v) put_octal(s, sizeof(s), v)
static inline int dx(int c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 0xa;
if (c >= 'A' && c <= 'F')
return c - 'A' + 0xa;
return -1;
}
static int get_octal(char *s, size_t l)
{
unsigned int val;
int ch;
val = 0;
while (l && s[0] != 0) {
ch = dx(s[0]);
if (ch < 0 || ch >= 8)
break;
val *= 8;
val += ch;
s++;
l--;
}
return val;
}
static void put_octal(char *s, size_t l, size_t value)
{
char *ptr = &s[l - 1];
*(ptr--) = '\0';
while (value != 0 && ptr >= s) {
*(ptr--) = '0' + (value % 8);
value /= 8;
}
while (ptr >= s)
*(ptr--) = '0';
}
static int usage(void)
{
fprintf(stderr,
"abuild-tar " VERSION "\n"
"\n"
"usage: abuild-tar [--hash [<algorithm>]] [--no-end]\n"
"\n"
"options:\n"
" --hash [sha1|md5] Read tar archive from stdin, precalculate hash for \n"
" regular entries and output tar archive on stdout\n"
" --no-end Remove the end of file tar record\n"
"\n");
}
static int do_it(const EVP_MD *md, int cut)
{
struct tar_header hdr;
size_t size, aligned_size;
void *ptr;
int dohash = 0, r;
struct {
char id[4];
uint16_t nid;
uint16_t size;
} mdinfo;
if (md != NULL) {
memcpy(mdinfo.id, "APK2", 4);
mdinfo.nid = EVP_MD_nid(md);
mdinfo.size = EVP_MD_size(md);
}
do {
if (read(STDIN_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
return 0;
if (cut && hdr.name[0] == 0)
return 0;
size = GET_OCTAL(hdr.size);
aligned_size = (size + 511) & ~511;
if (md != NULL)
dohash = (hdr.typeflag == '0' || hdr.typeflag == '7');
if (dohash) {
const unsigned char *src;
int chksum, i;
ptr = malloc(aligned_size);
if (read(STDIN_FILENO, ptr, aligned_size) != aligned_size)
return 1;
memcpy(&hdr.linkname[3], &mdinfo, sizeof(mdinfo));
EVP_Digest(ptr, size, &hdr.linkname[3+sizeof(mdinfo)],
NULL, md, NULL);
/* Recalculate checksum */
memset(hdr.chksum, ' ', sizeof(hdr.chksum));
src = (const unsigned char *) &hdr;
for (i = chksum = 0; i < sizeof(hdr); i++)
chksum += src[i];
put_octal(hdr.chksum, sizeof(hdr.chksum)-1, chksum);
}
if (write(STDOUT_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
return 2;
if (dohash) {
if (write(STDOUT_FILENO, ptr, aligned_size) != aligned_size)
return 2;
free(ptr);
} else if (aligned_size != 0) {
r = splice(STDIN_FILENO, NULL, STDOUT_FILENO, NULL,
aligned_size, 0);
if (r == -1) {
while (aligned_size > 0) {
if (read(STDIN_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
return 1;
if (write(STDOUT_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
return 2;
aligned_size -= sizeof(hdr);
}
} else if (r != aligned_size)
return 2;
}
} while (1);
}
int main(int argc, char **argv)
{
static int cut = 0;
static const struct option options[] = {
{ "hash", optional_argument },
{ "no-end", no_argument, &cut, 1 },
{ NULL }
};
const EVP_MD *md = NULL;
char *digest = NULL;
int ndx;
OpenSSL_add_all_algorithms();
ENGINE_load_builtin_engines();
ENGINE_register_all_complete();
while (getopt_long(argc, argv, "", options, &ndx) != -1) {
if (ndx == 0)
digest = optarg ? optarg : "sha1";
}
fprintf(stderr, "digest: %s, cut: %d\n", digest, cut);
if (digest == NULL && cut == 0)
return usage();
if (isatty(STDIN_FILENO))
return usage();
if (digest != NULL) {
md = EVP_get_digestbyname(digest);
if (md == NULL)
return usage();
}
return do_it(md, cut);
}
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