mds/app-arch/rpm5offset/files/rpmoffset.c

73 lines
1.9 KiB
C
Raw Normal View History

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