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 #include "compiler.h" 11 12 char **environ __attribute__((weak)); 13 const unsigned long *_auxv __attribute__((weak)); 14 15 void _start(void); 16 static void __stack_chk_init(void); 17 static void exit(int); 18 19 extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak)); 20 extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak)); 21 22 extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak)); 23 extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak)); 24 25 extern void (*const __fini_array_start[])(void) __attribute__((weak)); 26 extern void (*const __fini_array_end[])(void) __attribute__((weak)); 27 28 void _start_c(long *sp); 29 __attribute__((weak,used)) 30 #if __nolibc_has_feature(undefined_behavior_sanitizer) 31 __attribute__((no_sanitize("function"))) 32 #endif 33 void _start_c(long *sp) 34 { 35 long argc; 36 char **argv; 37 char **envp; 38 int exitcode; 39 void (* const *ctor_func)(int, char **, char **); 40 void (* const *dtor_func)(void); 41 const unsigned long *auxv; 42 /* silence potential warning: conflicting types for 'main' */ 43 int _nolibc_main(int, char **, char **) __asm__ ("main"); 44 45 /* initialize stack protector */ 46 __stack_chk_init(); 47 48 /* 49 * sp : argc <-- argument count, required by main() 50 * argv: argv[0] <-- argument vector, required by main() 51 * argv[1] 52 * ... 53 * argv[argc-1] 54 * null 55 * environ: environ[0] <-- environment variables, required by main() and getenv() 56 * environ[1] 57 * ... 58 * null 59 * _auxv: _auxv[0] <-- auxiliary vector, required by getauxval() 60 * _auxv[1] 61 * ... 62 * null 63 */ 64 65 /* assign argc and argv */ 66 argc = *sp; 67 argv = (void *)(sp + 1); 68 69 /* find environ */ 70 environ = envp = argv + argc + 1; 71 72 /* find _auxv */ 73 for (auxv = (void *)envp; *auxv++;) 74 ; 75 _auxv = auxv; 76 77 for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++) 78 (*ctor_func)(argc, argv, envp); 79 for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++) 80 (*ctor_func)(argc, argv, envp); 81 82 /* go to application */ 83 exitcode = _nolibc_main(argc, argv, envp); 84 85 for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;) 86 (*--dtor_func)(); 87 88 exit(exitcode); 89 } 90 91 #endif /* _NOLIBC_CRT_H */ 92