abuild/abuild-tar.c
2021-09-21 11:29:13 +02:00

402 lines
8.4 KiB
C

/* abuild-tar.c - A TAR mangling utility for .APK packages
*
* Copyright (C) 2009-2014 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.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <stdint.h>
#include <getopt.h>
#include <unistd.h>
#include <string.h>
#include <openssl/evp.h>
#include <openssl/engine.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]; /* 500-511 */
};
#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 size_t get_octal(char *s, size_t l)
{
size_t 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 void tarhdr_checksum(struct tar_header *hdr)
{
const unsigned char *src;
size_t chksum, i;
/* 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);
}
static int usage(void)
{
fprintf(stderr,
"abuild-tar " VERSION "\n"
"\n"
"usage: abuild-tar [--hash[=<algorithm>]] [--cut]\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"
" --cut Remove the end of file tar record\n"
"\n");
return 1;
}
static ssize_t full_read(int fd, void *buf, size_t count)
{
ssize_t total, n;
total = 0;
do {
n = read(fd, buf, count);
if (n < 0 && errno == EINTR)
continue;
if (n <= 0)
break;
buf += n;
total += n;
count -= n;
} while (1);
if (total == 0 && n < 0)
return -errno;
return total;
}
static ssize_t full_write(int fd, const void *buf, size_t count)
{
ssize_t total, n;
total = 0;
do {
n = write(fd, buf, count);
if (n < 0 && errno == EINTR)
continue;
if (n <= 0)
break;
buf += n;
total += n;
count -= n;
} while (1);
if (total == 0 && n < 0)
return -errno;
return total;
}
#if defined(__linux__)
static ssize_t full_splice(int from_fd, int to_fd, size_t count)
{
ssize_t total, n;
total = 0;
do {
n = splice(from_fd, NULL, to_fd, NULL, count, 0);
if (n < 0 && errno == EINTR)
continue;
if (n <= 0)
break;
count -= n;
total += n;
} while (1);
if (total == 0 && n < 0)
return -errno;
return total;
}
#else
#define full_splice(from_fd, to_fd, count) -1
#endif
#define BUF_INITIALIZER {0}
struct buf {
char *ptr;
size_t size;
size_t alloc;
};
static void buf_free(struct buf *b)
{
free(b->ptr);
}
static int buf_resize(struct buf *b, size_t newsize)
{
void *ptr;
if (b->alloc >= newsize) return 0;
ptr = realloc(b->ptr, newsize);
if (!ptr) return -ENOMEM;
b->ptr = ptr;
b->alloc = newsize;
return 0;
}
static int buf_padto(struct buf *b, size_t alignment)
{
size_t oldsize, newsize;
oldsize = b->size;
newsize = (oldsize + alignment - 1) & -alignment;
if (buf_resize(b, newsize)) return -ENOMEM;
b->size = newsize;
memset(b->ptr + oldsize, 0, newsize - oldsize);
return 0;
}
static int buf_read_fd(struct buf *b, int fd, size_t size)
{
ssize_t r;
r = buf_resize(b, size);
if (r) return r;
r = full_read(fd, b->ptr, size);
if (r == size) {
b->size = r;
return 0;
}
b->size = 0;
if (r < 0) return r;
return -EIO;
}
static int buf_write_fd(struct buf *b, int fd)
{
ssize_t r;
r = full_write(fd, b->ptr, b->size);
if (r == b->size) return 0;
if (r < 0) return r;
return -ENOSPC;
}
static int buf_add_ext_header_hexdump(struct buf *b, const char *hdr, const unsigned char *value, int valuelen)
{
int i, len;
/* "%u %s=%s\n" */
len = 1 + 1 + strlen(hdr) + 1 + valuelen*2 + 1;
for (i = len; i > 9; i /= 10) len++;
if (buf_resize(b, b->size + len)) return -ENOMEM;
b->size += snprintf(&b->ptr[b->size], len, "%u %s=", len, hdr);
for (i = 0; i < valuelen; i++)
b->size += snprintf(&b->ptr[b->size], 3, "%02x", (int)value[i]);
b->ptr[b->size++] = '\n';
return 0;
}
static void add_legacy_checksum(struct tar_header *hdr, const EVP_MD *md, const unsigned char *digest)
{
struct {
char id[4];
uint16_t nid;
uint16_t size;
} mdinfo;
memcpy(mdinfo.id, "APK2", 4);
mdinfo.nid = EVP_MD_nid(md);
mdinfo.size = EVP_MD_size(md);
memcpy(&hdr->linkname[3], &mdinfo, sizeof(mdinfo));
memcpy(&hdr->linkname[3+sizeof(mdinfo)], digest, mdinfo.size);
tarhdr_checksum(hdr);
}
static int do_it(const EVP_MD *md, int cut)
{
char checksumhdr[32];
unsigned char digest[EVP_MAX_MD_SIZE];
struct buf data = BUF_INITIALIZER, pax = BUF_INITIALIZER;
struct tar_header hdr, paxhdr;
size_t size, aligned_size;
int dohash = 0, r, ret = 1;
memset(&paxhdr, 0, sizeof(paxhdr));
if (md) snprintf(checksumhdr, sizeof(checksumhdr), "APK-TOOLS.checksum.%s", EVP_MD_name(md));
do {
if (full_read(STDIN_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
goto err;
if (cut && hdr.name[0] == 0)
break;
size = GET_OCTAL(hdr.size);
aligned_size = (size + 511) & ~511;
if (hdr.typeflag == 'x') {
memcpy(&paxhdr, &hdr, sizeof(hdr));
if (buf_read_fd(&pax, STDIN_FILENO, aligned_size)) goto err;
pax.size = size;
continue;
}
dohash = md && (hdr.typeflag == '0' || hdr.typeflag == '7' || hdr.typeflag == '2');
if (dohash) {
if (buf_read_fd(&data, STDIN_FILENO, aligned_size)) goto err;
if (hdr.typeflag != '2') {
EVP_Digest(data.ptr, size, digest, NULL, md, NULL);
add_legacy_checksum(&hdr, md, digest);
} else {
EVP_Digest(hdr.linkname, strlen(hdr.linkname), digest, NULL, md, NULL);
}
buf_add_ext_header_hexdump(&pax, checksumhdr, digest, EVP_MD_size(md));
PUT_OCTAL(paxhdr.size, pax.size);
tarhdr_checksum(&paxhdr);
}
if (pax.size) {
/* write pax header + content */
if (full_write(STDOUT_FILENO, &paxhdr, sizeof(paxhdr)) != sizeof(paxhdr) ||
buf_padto(&pax, 512) ||
buf_write_fd(&pax, STDOUT_FILENO)) goto err;
}
if (full_write(STDOUT_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr)) goto err;
if (dohash) {
if (buf_write_fd(&data, STDOUT_FILENO)) goto err;
} else if (aligned_size != 0) {
r = full_splice(STDIN_FILENO, STDOUT_FILENO, aligned_size);
if (r == -1) {
while (aligned_size > 0) {
if (full_read(STDIN_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
goto err;
if (full_write(STDOUT_FILENO, &hdr, sizeof(hdr)) != sizeof(hdr))
goto err;
aligned_size -= sizeof(hdr);
}
} else if (r != aligned_size) goto err;
}
memset(&paxhdr, 0, sizeof(paxhdr));
pax.size = 0;
} while (1);
ret = 0;
err:
buf_free(&data);
buf_free(&pax);
return ret;
}
int main(int argc, char **argv)
{
static int cut = 0;
static const struct option options[] = {
{ "hash", optional_argument },
{ "cut", no_argument, &cut, 1 },
{ NULL }
};
const EVP_MD *md = NULL;
char *digest = NULL;
int ndx;
OpenSSL_add_all_algorithms();
#if defined(OPENSSL_VERSION_MAJOR) && OPENSSL_VERSION_MAJOR < 3
ENGINE_load_builtin_engines();
ENGINE_register_all_complete();
#endif
while (getopt_long(argc, argv, "", options, &ndx) != -1) {
if (ndx == 0)
digest = optarg ? optarg : "sha1";
}
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);
}