rpm2targz/rpmoffset.c



    1 /* Find how deeply inside an .RPM the real data is */
    2 /* kept, and report the offset in bytes */
    3 
    4 /* Wouldn't it be a lot more sane if we could just untar these things? */
    5 
    6 #include <stdlib.h>
    7 
    8 /* These offsets keep getting bigger, so we're going to just bite a 2MB */
    9 /* chunk of RAM right away so that we have enough.  Yeah, horrible */
   10 /* quick and dirty implementation, but hey -- it gets the job done. */
   11 
   12 #define RPMBUFSIZ 2097152
   13 const char magic[][3]={"\x1F\x8B\x08"/*gzip*/,"BZh"/*bzip2*/};
   14 
   15 main()
   16 {
   17         char *buff = malloc(RPMBUFSIZ),*eb,*p;
   18         for (p = buff, eb = buff + read(0,buff,RPMBUFSIZ); p < eb; p++)
   19                 if ((*p == magic[0][0] && p[1] == magic[0][1] && p[2] == magic[0][2]) ||
   20                     (*p == magic[1][0] && p[1] == magic[1][1] && p[2] == magic[1][2]))
   21                         printf("%d\n",p - buff),
   22                         exit(0);
   23         exit(1);
   24 }