sysdeps/generic/libc-start.c

   1 /* Copyright (C) 1998-2003, 2004 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <unistd.h>
  22 #include <ldsodefs.h>
  23 #include <bp-start.h>
  24 #include <bp-sym.h>
  25
  26 extern void __libc_init_first (int argc, char **argv, char **envp);
  27
  28 extern int __libc_multiple_libcs;
  29
  30 #include <tls.h>
  31 #ifndef SHARED
  32 # include <dl-osinfo.h>
  33 extern void __pthread_initialize_minimal (void)
  34 # if !(USE_TLS - 0) && !defined NONTLS_INIT_TP
  35      __attribute__ ((weak))
  36 # endif
  37      ;
  38 #endif
  39
  40 #ifdef HAVE_PTR_NTHREADS
  41 /* We need atomic operations.  */
  42 # include <atomic.h>
  43 #endif
  44
  45
  46 #ifdef LIBC_START_MAIN
  47 # ifdef LIBC_START_DISABLE_INLINE
  48 #  define STATIC static
  49 # else
  50 #  define STATIC static inline __attribute__ ((always_inline))
  51 # endif
  52 #else
  53 # define STATIC
  54 # define LIBC_START_MAIN BP_SYM (__libc_start_main)
  55 #endif
  56
  57 #ifdef MAIN_AUXVEC_ARG
  58 /* main gets passed a pointer to the auxiliary.  */
  59 # define MAIN_AUXVEC_DECL       , void *
  60 # define MAIN_AUXVEC_PARAM      , auxvec
  61 #else
  62 # define MAIN_AUXVEC_DECL
  63 # define MAIN_AUXVEC_PARAM
  64 #endif
  65
  66 STATIC int LIBC_START_MAIN (int (*main) (int, char **, char **
  67                                          MAIN_AUXVEC_DECL),
  68                             int argc,
  69                             char *__unbounded *__unbounded ubp_av,
  70 #ifdef LIBC_START_MAIN_AUXVEC_ARG
  71                             ElfW(auxv_t) *__unbounded auxvec,
  72 #endif
  73 #ifdef INIT_MAIN_ARGS
  74                             __typeof (main) init,
  75 #else
  76                             void (*init) (void),
  77 #endif
  78                             void (*fini) (void),
  79                             void (*rtld_fini) (void),
  80                             void *__unbounded stack_end)
  81      __attribute__ ((noreturn));
  82
  83 STATIC int
  84 LIBC_START_MAIN (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
  85                  int argc, char *__unbounded *__unbounded ubp_av,
  86 #ifdef LIBC_START_MAIN_AUXVEC_ARG
  87                  ElfW(auxv_t) *__unbounded auxvec,
  88 #endif
  89 #ifdef INIT_MAIN_ARGS
  90                  __typeof (main) init,
  91 #else
  92                  void (*init) (void),
  93 #endif
  94                  void (*fini) (void),
  95                  void (*rtld_fini) (void), void *__unbounded stack_end)
  96 {
  97   char *__unbounded *__unbounded ubp_ev = &ubp_av[argc + 1];
  98 #if __BOUNDED_POINTERS__
  99   char **argv;
 100 #else
 101 # define argv ubp_av
 102 #endif
 103
 104   /* Result of the 'main' function.  */
 105   int result;
 106
 107   __libc_multiple_libcs = &_dl_starting_up && !_dl_starting_up;
 108
 109   INIT_ARGV_and_ENVIRON;
 110
 111 #ifndef SHARED
 112   /* Store the lowest stack address.  This is done in ld.so if this is
 113      the code for the DSO.  */
 114   __libc_stack_end = stack_end;
 115
 116 # ifdef HAVE_AUX_VECTOR
 117   /* First process the auxiliary vector since we need to find the
 118      program header to locate an eventually present PT_TLS entry.  */
 119 #  ifndef LIBC_START_MAIN_AUXVEC_ARG
 120   ElfW(auxv_t) *__unbounded auxvec;
 121   {
 122     char *__unbounded *__unbounded evp = ubp_ev;
 123     while (*evp++ != NULL)
 124       ;
 125     auxvec = (ElfW(auxv_t) *__unbounded) evp;
 126   }
 127 #  endif
 128   _dl_aux_init (auxvec);
 129 # endif
 130 # ifdef DL_SYSDEP_OSCHECK
 131   if (!__libc_multiple_libcs)
 132     {
 133       /* This needs to run to initiliaze _dl_osversion before TLS
 134          setup might check it.  */
 135       DL_SYSDEP_OSCHECK (__libc_fatal);
 136     }
 137 # endif
 138
 139   /* Initialize the thread library at least a bit since the libgcc
 140      functions are using thread functions if these are available and
 141      we need to setup errno.  If there is no thread library and we
 142      handle TLS the function is defined in the libc to initialized the
 143      TLS handling.  */
 144 # if !(USE_TLS - 0) && !defined NONTLS_INIT_TP
 145   if (__pthread_initialize_minimal)
 146 # endif
 147     __pthread_initialize_minimal ();
 148 #endif
 149
 150   /* Register the destructor of the dynamic linker if there is any.  */
 151   if (__builtin_expect (rtld_fini != NULL, 1))
 152     __cxa_atexit ((void (*) (void *)) rtld_fini, NULL, NULL);
 153
 154   /* Call the initializer of the libc.  This is only needed here if we
 155      are compiling for the static library in which case we haven't
 156      run the constructors in `_dl_start_user'.  */
 157 #ifndef SHARED
 158   __libc_init_first (argc, argv, __environ);
 159 #endif
 160
 161   /* Register the destructor of the program, if any.  */
 162   if (fini)
 163     __cxa_atexit ((void (*) (void *)) fini, NULL, NULL);
 164
 165 #ifndef SHARED
 166   /* Some security at this point.  Prevent starting a SUID binary where
 167      the standard file descriptors are not opened.  We have to do this
 168      only for statically linked applications since otherwise the dynamic
 169      loader did the work already.  */
 170   if (__builtin_expect (__libc_enable_secure, 0))
 171     __libc_check_standard_fds ();
 172 #endif
 173
 174   /* Call the initializer of the program, if any.  */
 175 #ifdef SHARED
 176   if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
 177     GLRO(dl_debug_printf) ("\ninitialize program: %s\n\n", argv[0]);
 178 #endif
 179   if (init)
 180     (*init) (
 181 #ifdef INIT_MAIN_ARGS
 182              argc, argv, __environ MAIN_AUXVEC_PARAM
 183 #endif
 184              );
 185
 186 #ifdef SHARED
 187   if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_IMPCALLS, 0))
 188     GLRO(dl_debug_printf) ("\ntransferring control: %s\n\n", argv[0]);
 189 #endif
 190
 191 #ifdef HAVE_CLEANUP_JMP_BUF
 192   /* Memory for the cancellation buffer.  */
 193   struct pthread_unwind_buf unwind_buf;
 194
 195   int not_first_call;
 196   not_first_call = setjmp ((struct __jmp_buf_tag *) unwind_buf.cancel_jmp_buf);
 197   if (__builtin_expect (! not_first_call, 1))
 198     {
 199       struct pthread *self = THREAD_SELF;
 200
 201       /* Store old info.  */
 202       unwind_buf.priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
 203       unwind_buf.priv.data.cleanup = THREAD_GETMEM (self, cleanup);
 204
 205       /* Store the new cleanup handler info.  */
 206       THREAD_SETMEM (self, cleanup_jmp_buf, &unwind_buf);
 207
 208       /* Run the program.  */
 209       result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
 210     }
 211   else
 212     {
 213       /* Remove the thread-local data.  */
 214 # ifdef SHARED
 215       __libc_pthread_functions.ptr__nptl_deallocate_tsd ();
 216 # else
 217       extern void __nptl_deallocate_tsd (void) __attribute ((weak));
 218       __nptl_deallocate_tsd ();
 219 # endif
 220
 221       /* One less thread.  Decrement the counter.  If it is zero we
 222          terminate the entire process.  */
 223       result = 0;
 224 # ifdef SHARED
 225       int *const ptr = __libc_pthread_functions.ptr_nthreads;
 226 # else
 227       extern int __nptl_nthreads __attribute ((weak));
 228       int *const ptr = &__nptl_nthreads;
 229 # endif
 230
 231       if (! atomic_decrement_and_test (ptr))
 232         /* Not much left to do but to exit the thread, not the process.  */
 233         __exit_thread (0);
 234     }
 235 #else
 236   /* Nothing fancy, just call the function.  */
 237   result = main (argc, argv, __environ MAIN_AUXVEC_PARAM);
 238 #endif
 239
 240   exit (result);
 241 }