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