73 lines
1.9 KiB
C
73 lines
1.9 KiB
C
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/* Find how deeply inside an .RPM the real data is */
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/* kept, and report the offset in bytes */
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/* Wouldn't it be a lot more sane if we could just untar these things? */
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#include <stdlib.h>
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#include <stdio.h>
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/* These offsets keep getting bigger, so we're going to just bite a 2MB */
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/* chunk of RAM right away so that we have enough. Yeah, horrible */
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/* quick and dirty implementation, but hey -- it gets the job done. */
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#define RPMBUFSIZ 3145728
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main()
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{
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char *buff = malloc(RPMBUFSIZ),*eb,*p;
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for (p = buff, eb = buff + read(0,buff,RPMBUFSIZ); p < eb; p++)
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{
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/* gzip format */
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if (*p == '\037' && p[1] == '\213' && p[2] == '\010')
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{
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printf("%ld\n",p - buff);
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exit(0);
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}
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/* bzip2 format */
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else if (*p == 'B' && p[1] == 'Z' && p[2] == 'h' )
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{
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printf("%ld\n",p - buff);
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exit(0);
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}
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/* LZMA files; both LZMA_Alone and LZMA utils formats. The LZMA_Alone
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* format is used by the LZMA_Alone tool from LZMA SDK. The LZMA utils
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* format is the default format of LZMA utils 4.32.1 and later. */
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/* LZMA utils format */
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else if (*p == '\377' && p[1] == 'L' &&
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p[2] == 'Z' && p[3] == 'M' &&
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p[4] == 'A' && p[5] == '\000')
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{
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printf("%ld\n",p - buff);
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exit(0);
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}
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/* The LZMA_Alone format has no magic bytes, thus we
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* need to play a wizard. This can give false positives,
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* thus the detection below should be removed when
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* the newer LZMA utils format has got popular. */
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// else if (*p == 0x5D && p[1] == 0x00 &&
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else if (*p == '\135' &&
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p[5] == '\377' && p[6] == '\377' &&
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p[7] == '\377' && p[8] == '\377' &&
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p[9] == '\377' && p[10] == '\377' &&
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p[11] == '\377' && p[12] == '\377')
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/* ((p[10] == 0x00 && p[11] == 0x00 &&
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p[12] == 0x00) ||
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(p[5] == 0xFF && p[6] == 0xFF &&
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p[7] == 0xFF && p[8] == 0xFF &&
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p[9] == 0xFF && p[10] == 0xFF &&
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p[11] == 0xFF && p[12] == 0xFF)))
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*/ {
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printf("%ld\n",p - buff);
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exit(0);
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}
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}
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exit(1);
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}
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