commands/mdb/gnu_load.c

   1 /*
   2  * gnu_load for mdb.c
   3  */
   4
   5 #include <stdio.h>
   6 #include <sys/types.h>
   7 #include <unistd.h>
   8 #include <stdlib.h>
   9 #include <fcntl.h>
  10 #include <gnu/a.out.h>
  11
  12 _PROTOTYPE( unsigned int gnu_load, (char *filename, struct nlist **start) );
  13 _PROTOTYPE( void do_error, (char *message) );
  14
  15 unsigned int gnu_load( filename, start)
  16 char *filename;
  17 struct nlist **start;
  18 {
  19         struct exec header;
  20         unsigned int nsym, string_size;
  21         char *names;
  22         struct nlist *p;
  23         int fd;
  24
  25         if ( (fd = open( filename, 0)) < 0 ||
  26              read( fd, (char *) &header, sizeof header ) != sizeof header )
  27         {
  28                 do_error( "gnu_load" );
  29                 if ( fd >= 0) close( fd );
  30                 return 0;
  31         }
  32
  33         if ( lseek( fd, N_STROFF( header ), 0 ) != N_STROFF( header ) )
  34         {
  35                 do_error( "gnu_load - reading header" );
  36                 close( fd );
  37                 return 0;
  38         }
  39
  40         if ( read( fd, (char *) &string_size, sizeof string_size ) < 0 )
  41         {
  42                 do_error( "gnu_load - reading header" );
  43                 close( fd );
  44                 return 0;
  45         }
  46
  47         if ( (int) header.a_syms < 0 ||
  48                 (unsigned) header.a_syms != header.a_syms ||
  49              (*start = (struct nlist *) malloc( (unsigned) header.a_syms +
  50                         string_size ))
  51                                 == (struct nlist *) NULL &&
  52              header.a_syms != 0 )
  53         {
  54                 close( fd );
  55                 return 0;
  56         }
  57
  58         lseek( fd, N_SYMOFF( header ), 0 );
  59
  60         if ( read( fd, (char *) *start, (int) header.a_syms + string_size ) < 0 )
  61         {
  62                 do_error( "gnu_load - reading symbols" );
  63                 close( fd );
  64                 return 0;
  65         }
  66         close( fd );
  67
  68         nsym = (unsigned int) header.a_syms / sizeof (struct nlist);
  69         names = (char *) *start + header.a_syms;
  70
  71         for ( p = *start; p < *start + nsym; p++)
  72                 if(p->n_un.n_strx)
  73                         p->n_un.n_name = names + p->n_un.n_strx;
  74
  75         return nsym;
  76 }