elf/unload2.c

   1 #include <dlfcn.h>
   2 #include <elf.h>
   3 #include <errno.h>
   4 #include <error.h>
   5 #include <link.h>
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8
   9 #define MAPS ((struct link_map *) _r_debug.r_map)
  10
  11 #define OUT \
  12   for (map = MAPS; map != NULL; map = map->l_next)                            \
  13     if (map->l_type == lt_loaded)                                             \
  14       printf ("name = \"%s\", direct_opencount = %d\n",                       \
  15               map->l_name, (int) map->l_direct_opencount);                    \
  16   fflush (stdout)
  17
  18 int
  19 main (void)
  20 {
  21   void *h[3];
  22   struct link_map *map;
  23   void (*fp) (void);
  24
  25   h[0] = dlopen ("unload2mod.so", RTLD_LAZY);
  26   h[1] = dlopen ("unload2mod.so", RTLD_LAZY);
  27   if (h[0] == NULL || h[1] == NULL)
  28     error (EXIT_FAILURE, errno, "cannot load \"unload2mod.so\"");
  29   h[2] = dlopen ("unload2dep.so", RTLD_LAZY);
  30   if (h[2] == NULL)
  31     error (EXIT_FAILURE, errno, "cannot load \"unload2dep.so\"");
  32
  33   puts ("\nAfter loading everything:");
  34   OUT;
  35
  36   dlclose (h[0]);
  37
  38   puts ("\nAfter unloading \"unload2mod.so\" once:");
  39   OUT;
  40
  41   dlclose (h[1]);
  42
  43   puts ("\nAfter unloading \"unload2mod.so\" twice:");
  44   OUT;
  45
  46   fp = dlsym (h[2], "foo");
  47   puts ("\nnow calling `foo'");
  48   fflush (stdout);
  49   fp ();
  50   puts ("managed to call `foo'");
  51   fflush (stdout);
  52
  53   dlclose (h[2]);
  54
  55   puts ("\nAfter unloading \"unload2dep.so\":");
  56   OUT;
  57
  58   return 0;
  59 }