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 /* We have to initialize the thread library at least if bit.  */
  44 extern void __pthread_initialize_minimal (void) __attribute__ ((weak));
  45
  46 /* This function will be called from _init in init-first.c.  */
  47 void
  48 __libc_global_ctors (void)
  49 {
  50   /* Call constructor functions.  */
  51   run_hooks (__CTOR_LIST__);
  52
  53   /* Initialize the thread library at least a bit since the libgcc functions
  54      are using thread functions if these are available.  */
  55   if (__pthread_initialize_minimal)
  56     __pthread_initialize_minimal ();
  57
  58 #ifdef HAVE_DWARF2_UNWIND_INFO
  59 # ifdef HAVE_DWARF2_UNWIND_INFO_STATIC
  60   {
  61     static struct object ob;
  62     __register_frame_info (__EH_FRAME_BEGIN__, &ob);
  63   }
  64 # else
  65   __register_frame (__EH_FRAME_BEGIN__);
  66 # endif
  67 #endif
  68 }
  69
  70
  71 /* This function becomes the DT_FINI termination function
  72    for the C library.  */
  73 void _fini (void) __attribute__ ((section (".fini"))); /* Just for kicks.  */
  74 void
  75 _fini (void)
  76 {
  77   /* Call destructor functions.  */
  78   run_hooks (__DTOR_LIST__);
  79 #ifdef HAVE_DWARF2_UNWIND_INFO
  80 # ifdef HAVE_DWARF2_UNWIND_INFO_STATIC
  81   __deregister_frame_info (__EH_FRAME_BEGIN__);
  82 # else
  83   __deregister_frame (__EH_FRAME_BEGIN__);
  84 # endif
  85 #endif
  86 }