1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */ 2 /* 3 * C Run Time support for NOLIBC 4 * Copyright (C) 2023 Zhangjin Wu <falcon@tinylab.org> 5 */ 6 7 #ifndef _NOLIBC_CRT_H 8 #define _NOLIBC_CRT_H 9 10 char **environ __attribute__((weak)); 11 const unsigned long *_auxv __attribute__((weak)); 12 13 void _start(void); 14 static void __stack_chk_init(void); 15 static void exit(int); 16 17 extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak)); 18 extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak)); 19 20 extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak)); 21 extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak)); 22 23 extern void (*const __fini_array_start[])(void) __attribute__((weak)); 24 extern void (*const __fini_array_end[])(void) __attribute__((weak)); 25 26 void _start_c(long *sp); 27 __attribute__((weak,used)) 28 void _start_c(long *sp) 29 { 30 long argc; 31 char **argv; 32 char **envp; 33 int exitcode; 34 void (* const *ctor_func)(int, char **, char **); 35 void (* const *dtor_func)(void); 36 const unsigned long *auxv; 37 /* silence potential warning: conflicting types for 'main' */ 38 int _nolibc_main(int, char **, char **) __asm__ ("main"); 39 40 /* initialize stack protector */ 41 __stack_chk_init(); 42 43 /* 44 * sp : argc <-- argument count, required by main() 45 * argv: argv[0] <-- argument vector, required by main() 46 * argv[1] 47 * ... 48 * argv[argc-1] 49 * null 50 * environ: environ[0] <-- environment variables, required by main() and getenv() 51 * environ[1] 52 * ... 53 * null 54 * _auxv: _auxv[0] <-- auxiliary vector, required by getauxval() 55 * _auxv[1] 56 * ... 57 * null 58 */ 59 60 /* assign argc and argv */ 61 argc = *sp; 62 argv = (void *)(sp + 1); 63 64 /* find environ */ 65 environ = envp = argv + argc + 1; 66 67 /* find _auxv */ 68 for (auxv = (void *)envp; *auxv++;) 69 ; 70 _auxv = auxv; 71 72 for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++) 73 (*ctor_func)(argc, argv, envp); 74 for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++) 75 (*ctor_func)(argc, argv, envp); 76 77 /* go to application */ 78 exitcode = _nolibc_main(argc, argv, envp); 79 80 for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;) 81 (*--dtor_func)(); 82 83 exit(exitcode); 84 } 85 86 #endif /* _NOLIBC_CRT_H */ 87