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| -rw-r--r-- | abuild-tar.c | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/abuild-tar.c b/abuild-tar.c new file mode 100644 index 0000000..68f9808 --- /dev/null +++ b/abuild-tar.c @@ -0,0 +1,213 @@ +/* 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); +} |