elf/soinit.c

   1 /* Initializer module for building the ELF shared C library.  This file and
   2    sofini.c do the work normally done by crtbeginS.o and crtendS.o, to wrap
   3    the `.ctors' and `.dtors' sections so the lists are terminated, and
   4    calling those lists of functions.  */
   5
   6 static void (*const __CTOR_LIST__[1]) (void)
   7      __attribute__ ((section (".ctors")))
   8      = { (void (*) (void)) -1 };
   9 static void (*const __DTOR_LIST__[1]) (void)
  10      __attribute__ ((section (".dtors")))
  11      = { (void (*) (void)) -1 };
  12
  13 static inline void
  14 run_hooks (void (*const list[]) (void))
  15 {
  16   while (*++list)
  17     (**list) ();
  18 }
  19
  20 #ifdef HAVE_DWARF2_UNWIND_INFO
  21 static char __EH_FRAME_BEGIN__[]
  22      __attribute__ ((section (".eh_frame")))
  23      = { };
  24 # ifdef HAVE_DWARF2_UNWIND_INFO_STATIC
  25 /* This must match what's in frame.h in gcc. How can one do that? */
  26 struct object
  27 {
  28   void *pc_begin;
  29   void *pc_end;
  30   void *fde_begin;
  31   void *fde_array;
  32   __SIZE_TYPE__ count;
  33   struct object *next;
  34 };
  35 extern void __register_frame_info (const void *, struct object *);
  36 extern void __deregister_frame_info (const void *);
  37 # else
  38 extern void __register_frame (const void *);
  39 extern void __deregister_frame (const void *);
  40 # endif
  41 #endif
  42
  43 /* This function will be called from _init in init-first.c.  */
  44 void
  45 __libc_global_ctors (void)
  46 {
  47   /* Call constructor functions.  */
  48   run_hooks (__CTOR_LIST__);
  49 #ifdef HAVE_DWARF2_UNWIND_INFO
  50 # ifdef HAVE_DWARF2_UNWIND_INFO_STATIC
  51   {
  52     static struct object ob;
  53     __register_frame_info (__EH_FRAME_BEGIN__, &ob);
  54   }
  55 # else
  56   __register_frame (__EH_FRAME_BEGIN__);
  57 # endif
  58 #endif
  59 }
  60
  61
  62 /* This function becomes the DT_FINI termination function
  63    for the C library.  */
  64 void _fini (void) __attribute__ ((section (".fini"))); /* Just for kicks.  */
  65 void
  66 _fini (void)
  67 {
  68   /* Call destructor functions.  */
  69   run_hooks (__DTOR_LIST__);
  70 #ifdef HAVE_DWARF2_UNWIND_INFO
  71 # ifdef HAVE_DWARF2_UNWIND_INFO_STATIC
  72   __deregister_frame_info (__EH_FRAME_BEGIN__);
  73 # else
  74   __deregister_frame (__EH_FRAME_BEGIN__);
  75 # endif
  76 #endif
  77 }