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 #ifndef NOLIBC_NO_RUNTIME 11 12 #include "compiler.h" 13 14 char **environ __attribute__((weak)); 15 const unsigned long *_auxv __attribute__((weak)); 16 17 void _start(void); 18 static void __stack_chk_init(void); 19 static void exit(int); 20 21 extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak)); 22 extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak)); 23 24 extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak)); 25 extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak)); 26 27 extern void (*const __fini_array_start[])(void) __attribute__((weak)); 28 extern void (*const __fini_array_end[])(void) __attribute__((weak)); 29 30 void _start_c(long *sp); 31 __attribute__((weak,used)) 32 #if __nolibc_has_feature(undefined_behavior_sanitizer) 33 __attribute__((no_sanitize("function"))) 34 #endif 35 void _start_c(long *sp) 36 { 37 long argc; 38 char **argv; 39 char **envp; 40 int exitcode; 41 void (* const *ctor_func)(int, char **, char **); 42 void (* const *dtor_func)(void); 43 const unsigned long *auxv; 44 /* silence potential warning: conflicting types for 'main' */ 45 int _nolibc_main(int, char **, char **) __asm__ ("main"); 46 47 /* initialize stack protector */ 48 __stack_chk_init(); 49 50 /* 51 * sp : argc <-- argument count, required by main() 52 * argv: argv[0] <-- argument vector, required by main() 53 * argv[1] 54 * ... 55 * argv[argc-1] 56 * null 57 * environ: environ[0] <-- environment variables, required by main() and getenv() 58 * environ[1] 59 * ... 60 * null 61 * _auxv: _auxv[0] <-- auxiliary vector, required by getauxval() 62 * _auxv[1] 63 * ... 64 * null 65 */ 66 67 /* assign argc and argv */ 68 argc = *sp; 69 argv = (void *)(sp + 1); 70 71 /* find environ */ 72 environ = envp = argv + argc + 1; 73 74 /* find _auxv */ 75 for (auxv = (void *)envp; *auxv++;) 76 ; 77 _auxv = auxv; 78 79 for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++) 80 (*ctor_func)(argc, argv, envp); 81 for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++) 82 (*ctor_func)(argc, argv, envp); 83 84 /* go to application */ 85 exitcode = _nolibc_main(argc, argv, envp); 86 87 for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;) 88 (*--dtor_func)(); 89 90 exit(exitcode); 91 } 92 93 #endif /* NOLIBC_NO_RUNTIME */ 94 #endif /* _NOLIBC_CRT_H */ 95