elf/reldep2.c

   1 #include <dlfcn.h>
   2 #include <mcheck.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5
   6 int
   7 main (void)
   8 {
   9   void *h1;
  10   void *h2;
  11   int (*fp) (void);
  12   int *vp;
  13
  14   mtrace ();
  15
  16   /* Open the two objects.  */
  17   h1 = dlopen ("reldepmod1.so", RTLD_LAZY | RTLD_GLOBAL);
  18   if (h1 == NULL)
  19     {
  20       printf ("cannot open reldepmod1.so: %s\n", dlerror ());
  21       exit (1);
  22     }
  23   h2 = dlopen ("reldepmod3.so", RTLD_LAZY);
  24   if (h2 == NULL)
  25     {
  26       printf ("cannot open reldepmod3.so: %s\n", dlerror ());
  27       exit (1);
  28     }
  29
  30   /* Get the address of the variable in reldepmod1.so.  */
  31   vp = dlsym (h1, "some_var");
  32   if (vp == NULL)
  33     {
  34       printf ("cannot get address of \"some_var\": %s\n", dlerror ());
  35       exit (1);
  36     }
  37
  38   *vp = 42;
  39
  40   /* Get the function `call_me' in the second object.  This has a
  41      dependency which is resolved by a definition in reldepmod1.so.  */
  42   fp = dlsym (h2, "call_me");
  43   if (fp == NULL)
  44     {
  45       printf ("cannot get address of \"call_me\": %s\n", dlerror ());
  46       exit (1);
  47     }
  48
  49   /* Call the function.  */
  50   if (fp () != 0)
  51     {
  52       puts ("function \"call_me\" returned wrong result");
  53       exit (1);
  54     }
  55
  56   /* Now close the first object.  It must still be around since we have
  57      an implicit dependency.  */
  58   if (dlclose (h1) != 0)
  59     {
  60       printf ("closing h1 failed: %s\n", dlerror ());
  61       exit (1);
  62     }
  63
  64   /* Open the first object again.   */
  65   h1 = dlopen ("reldepmod1.so", RTLD_LAZY | RTLD_GLOBAL);
  66   if (h1 == NULL)
  67     {
  68       printf ("cannot open reldepmod1.so the second time: %s\n", dlerror ());
  69       exit (1);
  70     }
  71
  72   /* Get the variable address again.  */
  73   vp = dlsym (h1, "some_var");
  74   if (vp == NULL)
  75     {
  76       printf ("cannot get address of \"some_var\" the second time: %s\n",
  77               dlerror ());
  78       exit (1);
  79     }
  80
  81   /* The variable now must have its originial value.  */
  82   if (*vp != 42)
  83     {
  84       puts ("variable \"some_var\" reset");
  85       exit (1);
  86     }
  87
  88   /* Close the first object again, we are done.  */
  89   if (dlclose (h1) != 0)
  90     {
  91       printf ("closing h1 failed: %s\n", dlerror ());
  92       exit (1);
  93     }
  94   if (dlclose (h2) != 0)
  95     {
  96       printf ("closing h2 failed: %s\n", dlerror ());
  97       exit (1);
  98     }
  99
 100   return 0;
 101 }