glibc/sysdeps/generic/libc-start.c

/* Copyright (C) 1998,1999,2000,2001,2002,2003 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <ldsodefs.h>
#include <bp-start.h>
#include <bp-sym.h>

extern void __libc_init_first (int argc, char **argv, char **envp);

extern int __libc_multiple_libcs;
extern void *__libc_stack_end;

#ifdef NEED_DL_SYSINFO
# include "unwind-dw2-fde.h"
extern __typeof (__register_frame_info_bases)
     INTUSE(__register_frame_info_bases);
static struct object eh_obj;
#endif

#include <tls.h>
#ifndef SHARED
# include <dl-osinfo.h>
extern void __pthread_initialize_minimal (void)
# if !(USE_TLS - 0) && !defined NONTLS_INIT_TP
     __attribute__ ((weak))
# endif
     ;
#endif

#ifdef HAVE_PTR_NTHREADS
/* We need atomic operations.  */
# include <atomic.h>
#endif


#ifdef LIBC_START_MAIN
# define STATIC static inline
#else
# define STATIC
# define LIBC_START_MAIN BP_SYM (__libc_start_main)
#endif

#ifdef MAIN_AUXVEC_ARG
/* main gets passed a pointer to the auxiliary.  */
# define MAIN_AUXVEC_DECL	, void *
# define MAIN_AUXVEC_PARAM	, auxvec
#else
# define MAIN_AUXVEC_DECL
# define MAIN_AUXVEC_PARAM
#endif

STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
					 MAIN_AUXVEC_DECL),
			    int argc,
			    char *__unbounded *__unbounded ubp_av,
#ifdef LIBC_START_MAIN_AUXVEC_ARG
			    ElfW(auxv_t) *__unbounded auxvec,
#endif
#ifdef INIT_MAIN_ARGS
			    __typeof (main) init,
#else
			    void (*init) (void),
#endif
			    void (*fini) (void),
			    void (*rtld_fini) (void),
			    void *__unbounded stack_end)
     __attribute__ ((noreturn));

STATIC int
LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
		 int argc, char *__unbounded *__unbounded ubp_av,
#ifdef LIBC_START_MAIN_AUXVEC_ARG
		 ElfW(auxv_t) *__unbounded auxvec,
#endif
#ifdef INIT_MAIN_ARGS
		 __typeof (main) init,
#else
		 void (*init) (void),
#endif
		 void (*fini) (void),
		 void (*rtld_fini) (void), void *__unbounded stack_end)
{
  char *__unbounded *__unbounded ubp_ev = &ubp_av[argc + 1];
#if __BOUNDED_POINTERS__
  char **argv;
#else
# define argv ubp_av
#endif

  /* Result of the 'main' function.  */
  int result;

  __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;

  INIT_ARGV_and_ENVIRON;

  /* Store the lowest stack address.  */
  __libc_stack_end = stack_end;

#ifndef SHARED
# ifdef HAVE_AUX_VECTOR
  /* First process the auxiliary vector since we need to find the
     program header to locate an eventually present PT_TLS entry.  */
#  ifndef LIBC_START_MAIN_AUXVEC_ARG
  ElfW(auxv_t) *__unbounded auxvec;
  {
    char *__unbounded *__unbounded evp = ubp_ev;
    while (*evp++ != NULL)
      ;
    auxvec = (ElfW(auxv_t) *__unbounded) evp;
  }
#  endif
  _dl_aux_init (auxvec);
# endif
# ifdef DL_SYSDEP_OSCHECK
  if (!__libc_multiple_libcs)
    {
      /* This needs to run to initiliaze _dl_osversion before TLS
	 setup might check it.  */
      DL_SYSDEP_OSCHECK (__libc_fatal);
    }
# endif

  /* Initialize the thread library at least a bit since the libgcc
     functions are using thread functions if these are available and
     we need to setup errno.  If there is no thread library and we
     handle TLS the function is defined in the libc to initialized the
     TLS handling.  */
# if !(USE_TLS - 0) && !defined NONTLS_INIT_TP
  if (__pthread_initialize_minimal)
# endif
    __pthread_initialize_minimal ();

  /* Some security at this point.  Prevent starting a SUID binary where
     the standard file descriptors are not opened.  We have to do this
     only for statically linked applications since otherwise the dynamic
     loader did the work already.  */
  if (__builtin_expect (__libc_enable_secure, 0))
    __libc_check_standard_fds ();
#endif

#ifdef NEED_DL_SYSINFO
  /* Register the kernel's unwind table.  */
  if (GL(dl_sysinfo_eh_frame) != 0)
    INTUSE(__register_frame_info_bases) ((void *) GL(dl_sysinfo_eh_frame),
					 &eh_obj, 0, 0);
#endif

  /* Register the destructor of the dynamic linker if there is any.  */
  if (__builtin_expect (rtld_fini != NULL, 1))
    __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);

  /* Call the initializer of the libc.  This is only needed here if we
     are compiling for the static library in which case we haven't
     run the constructors in `_dl_start_user'.  */
#ifndef SHARED
  __libc_init_first (argc, argv, __environ);
#endif

  /* Register the destructor of the program, if any.  */
  if (fini)
    __cxa_atexit ((void (*) (void *)) fini, NULL, NULL);

  /* Call the initializer of the program, if any.  */
#ifdef SHARED
  if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
    _dl_debug_printf ("\ninitialize program: %s\n\n", argv[0]);
#endif
  if (init)
    (*init) (
#ifdef INIT_MAIN_ARGS
	     argc, argv, __environ MAIN_AUXVEC_PARAM
#endif
	     );

#ifdef SHARED
  if (__builtin_expect (GL(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
    _dl_debug_printf ("\ntransferring control: %s\n\n", argv[0]);
#endif

#ifdef HAVE_CLEANUP_JMP_BUF
  /* Memory for the cancellation buffer.  */
  struct pthread_unwind_buf unwind_buf;

  int not_first_call;
  not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
  if (__builtin_expect (! not_first_call, 1))
    {
      struct pthread *self = THREAD_SELF;

      /* Store old info.  */
      unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
      unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);

      /* Store the new cleanup handler info.  */
      THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);

      /* Run the program.  */
      result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
    }
  else
    {
      /* One less thread.  Decrement the counter.  If it is zero we
	 terminate the entire process.  */
      result = 0;
# ifdef SHARED
      int *const ptr = __libc_pthread_functions.ptr_nthreads;
# else
      extern int __nptl_nthreads __attribute ((weak));
      int *const ptr = &__nptl_nthreads;
# endif

      if (! atomic_decrement_and_test (ptr))
	/* Not much left to do but to exit the thread, not the process.  */
	__exit_thread (0);
    }
#else
  /* Nothing fancy, just call the function.  */
  result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
#endif

  exit (result);
}