elf-init-2.33.c (3822B) - Raw
1 /* Startup support for ELF initializers/finalizers in the main executable. 2 Copyright (C) 2002-2020 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 In addition to the permissions in the GNU Lesser General Public 11 License, the Free Software Foundation gives you unlimited 12 permission to link the compiled version of this file with other 13 programs, and to distribute those programs without any restriction 14 coming from the use of this file. (The GNU Lesser General Public 15 License restrictions do apply in other respects; for example, they 16 cover modification of the file, and distribution when not linked 17 into another program.) 18 19 Note that people who make modified versions of this file are not 20 obligated to grant this special exception for their modified 21 versions; it is their choice whether to do so. The GNU Lesser 22 General Public License gives permission to release a modified 23 version without this exception; this exception also makes it 24 possible to release a modified version which carries forward this 25 exception. 26 27 The GNU C Library is distributed in the hope that it will be useful, 28 but WITHOUT ANY WARRANTY; without even the implied warranty of 29 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 30 Lesser General Public License for more details. 31 32 You should have received a copy of the GNU Lesser General Public 33 License along with the GNU C Library; if not, see 34 <https://www.gnu.org/licenses/>. */ 35 36 #include <stddef.h> 37 38 39 /* These magic symbols are provided by the linker. */ 40 extern void (*__preinit_array_start []) (int, char **, char **) 41 attribute_hidden; 42 extern void (*__preinit_array_end []) (int, char **, char **) 43 attribute_hidden; 44 extern void (*__init_array_start []) (int, char **, char **) 45 attribute_hidden; 46 extern void (*__init_array_end []) (int, char **, char **) 47 attribute_hidden; 48 extern void (*__fini_array_start []) (void) attribute_hidden; 49 extern void (*__fini_array_end []) (void) attribute_hidden; 50 51 52 #ifndef NO_INITFINI 53 /* These function symbols are provided for the .init/.fini section entry 54 points automagically by the linker. */ 55 extern void _init (void); 56 extern void _fini (void); 57 #endif 58 59 60 /* These functions are passed to __libc_start_main by the startup code. 61 These get statically linked into each program. For dynamically linked 62 programs, this module will come from libc_nonshared.a and differs from 63 the libc.a module in that it doesn't call the preinit array. */ 64 65 66 void 67 __libc_csu_init (int argc, char **argv, char **envp) 68 { 69 /* For dynamically linked executables the preinit array is executed by 70 the dynamic linker (before initializing any shared object). */ 71 72 #ifndef LIBC_NONSHARED 73 /* For static executables, preinit happens right before init. */ 74 { 75 const size_t size = __preinit_array_end - __preinit_array_start; 76 size_t i; 77 for (i = 0; i < size; i++) 78 (*__preinit_array_start [i]) (argc, argv, envp); 79 } 80 #endif 81 82 #ifndef NO_INITFINI 83 _init (); 84 #endif 85 86 const size_t size = __init_array_end - __init_array_start; 87 for (size_t i = 0; i < size; i++) 88 (*__init_array_start [i]) (argc, argv, envp); 89 } 90 91 /* This function should not be used anymore. We run the executable's 92 destructor now just like any other. We cannot remove the function, 93 though. */ 94 void 95 __libc_csu_fini (void) 96 { 97 #ifndef LIBC_NONSHARED 98 size_t i = __fini_array_end - __fini_array_start; 99 while (i-- > 0) 100 (*__fini_array_start [i]) (); 101 102 # ifndef NO_INITFINI 103 _fini (); 104 # endif 105 #endif 106 }