diff options
Diffstat (limited to 'source/a/rpm2tgz/rpmoffset.c')
| -rw-r--r-- | source/a/rpm2tgz/rpmoffset.c | 145 |
1 files changed, 132 insertions, 13 deletions
diff --git a/source/a/rpm2tgz/rpmoffset.c b/source/a/rpm2tgz/rpmoffset.c index fd09e623b..99a5c16cf 100644 --- a/source/a/rpm2tgz/rpmoffset.c +++ b/source/a/rpm2tgz/rpmoffset.c @@ -4,22 +4,141 @@ /* Wouldn't it be a lot more sane if we could just untar these things? */ -#include <stdlib.h> +#ifndef _GNU_SOURCE +# define _GNU_SOURCE +#endif + +#include <stdint.h> #include <stdio.h> +#include <string.h> + +#ifndef ARRAY_SIZE +# define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0])) +#endif +#ifndef BUFSIZ +# define BUFSIZ 8192 +#endif -/* These offsets keep getting bigger, so we're going to just bite a 2MB */ -/* chunk of RAM right away so that we have enough. Yeah, horrible */ -/* quick and dirty implementation, but hey -- it gets the job done. */ +#if !defined(__GLIBC__) +static void *rp_memmem(const void *buf, size_t buflen, const void *pattern, size_t len) +{ + char *bf = (char *)buf, *pt = (char *)pattern, *p = bf; -#define RPMBUFSIZ 2097152 + while (len <= (buflen - (p - bf))) { + if (NULL != (p = memchr(p, (int)(*pt), buflen - (p - bf)))) { + if (0 == memcmp(p, pattern, len)) + return p; + else + ++p; + } + else + break; + } + return NULL; +} +#define memmem(a,b,c,d) rp_memmem(a,b,c,d) +#endif + +typedef struct { + const char *type; + const unsigned char *magic; + const size_t len; +} magic_t; + +/* LZMA is some fuzzy crap */ +int is_magic_lzma(const char *buf) +{ + const unsigned char *ubuf = (const void *)buf; + return (ubuf[0] == 0x5d && ubuf[4] < 0x20) && + (!memcmp(buf + 10, "\x00\x00\x00", 3) || + !memcmp(buf + 5, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF", 8)); +} +#define magic_lzma_len 13 + +static const unsigned char magic_gzip[] = { '\037', '\213', '\010' }; +static const unsigned char magic_bzip2[] = { 'B', 'Z', 'h' }; +static const unsigned char magic_xz[] = { 0xFD, '7', 'z', 'X', 'Z', 0x00 }; +static const unsigned char magic_zstd[] = { 0x28, 0xB5, 0x2F, 0xFD }; +static const magic_t magics[] = { +#define DECLARE_MAGIC_T(t) { .type = #t, .magic = magic_##t, .len = sizeof(magic_##t), }, + DECLARE_MAGIC_T(gzip) + DECLARE_MAGIC_T(bzip2) + DECLARE_MAGIC_T(xz) + DECLARE_MAGIC_T(zstd) +#undef DECLARE_MAGIC_T +}; +#define MAGIC_SIZE_MIN 3 +#define MAGIC_SIZE_MAX 13 + +static int show_magic; + +static int magic_finish(const char *magic, size_t offset) +{ + if (show_magic) + printf("%s ", magic); + printf("%zu\n", offset); + return 0; +} -main() +int main(int argc, char *argv[]) { - char *buff = malloc(RPMBUFSIZ),*eb,*p; - for (p = buff, eb = buff + read(0,buff,RPMBUFSIZ); p < eb; p++) - if ((*p == '\037' && p[1] == '\213' && p[2] == '\010') || - (*p == 'B' && p[1] == 'Z' && p[2] == 'h' && '1' <= p[3] && p[3] <= '9' )) - printf("%d\n",p - buff), - exit(0); - exit(1); + size_t i, read_cnt, offset, left, lzma_offset; + FILE *fp = stdin; + char p[BUFSIZ]; + + if (argc == 2 && !strcmp(argv[1], "-v")) { + show_magic = 1; + --argc; + } + + if (argc != 1) { + puts("Usage: rpmoffset < rpmfile"); + return 1; + } + /* fp = fopen(argv[1], "r"); */ + + lzma_offset = 0; + offset = left = 0; + while (1) { + read_cnt = fread(p + left, 1, sizeof(p) - left, fp); + if (read_cnt + left < MAGIC_SIZE_MIN) + break; + + for (i = 0; i < ARRAY_SIZE(magics); ++i) { + const char *needle; + + if (read_cnt + left < magics[i].len) + continue; + + needle = memmem(p, sizeof(p), magics[i].magic, magics[i].len); + if (needle) + return magic_finish(magics[i].type, offset + (needle - p)); + } + + /* Scan for LZMA magic, but don't return yet ... */ + if (!lzma_offset && read_cnt + left >= magic_lzma_len) { + for (i = 0; i <= read_cnt + left - magic_lzma_len; ++i) + if (is_magic_lzma(p + i)) { + lzma_offset = offset + i; + break; + } + } + + memmove(p, p + left + read_cnt - MAGIC_SIZE_MIN + 1, MAGIC_SIZE_MIN - 1); + + offset += read_cnt; + if (left == 0) { + offset -= MAGIC_SIZE_MIN - 1; + left = MAGIC_SIZE_MIN - 1; + } + } + + /* Delay till the end for LZMA archives since it is too fuzzy */ + if (lzma_offset) + return magic_finish("lzma", lzma_offset); + + if (ferror(stdin)) + perror(argv[0]); + + return 1; } |