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 #define __nolibc_arg_to_reg(_a) \ 11 __builtin_choose_expr(__builtin_classify_type(_a) == __builtin_classify_type(NULL), \ 12 (unsigned long)(_a), (_a)) 13 14 #ifndef NOLIBC_NO_RUNTIME 15 16 #include "compiler.h" 17 18 char **environ __attribute__((weak)); 19 const unsigned long *_auxv __attribute__((weak)); 20 21 void _start(void); 22 static void __stack_chk_init(void); 23 static void exit(int); 24 static char *strrchr(const char *s, int c); 25 26 extern void (*const __preinit_array_start[])(int, char **, char**) __attribute__((weak)); 27 extern void (*const __preinit_array_end[])(int, char **, char**) __attribute__((weak)); 28 29 extern void (*const __init_array_start[])(int, char **, char**) __attribute__((weak)); 30 extern void (*const __init_array_end[])(int, char **, char**) __attribute__((weak)); 31 32 extern void (*const __fini_array_start[])(void) __attribute__((weak)); 33 extern void (*const __fini_array_end[])(void) __attribute__((weak)); 34 35 #ifndef NOLIBC_IGNORE_ERRNO 36 extern char *program_invocation_name __attribute__((weak)); 37 extern char *program_invocation_short_name __attribute__((weak)); 38 39 static __inline__ 40 char *__nolibc_program_invocation_short_name(char *long_name) 41 { 42 43 char *short_name; 44 45 short_name = strrchr(long_name, '/'); 46 if (!short_name || !short_name[0]) 47 return long_name; 48 49 return short_name + 1; 50 } 51 #endif /* NOLIBC_IGNORE_ERRNO */ 52 53 void _start_c(long *sp); 54 __attribute__((weak,used)) __nolibc_no_sanitize_undefined __nolibc_no_stack_protector 55 void _start_c(long *sp) 56 { 57 long argc; 58 char **argv; 59 char **envp; 60 int exitcode; 61 void (* const *ctor_func)(int, char **, char **); 62 void (* const *dtor_func)(void); 63 const unsigned long *auxv; 64 /* silence potential warning: conflicting types for 'main' */ 65 int _nolibc_main(int, char **, char **) __asm__ ("main"); 66 67 /* initialize stack protector */ 68 __stack_chk_init(); 69 70 /* 71 * sp : argc <-- argument count, required by main() 72 * argv: argv[0] <-- argument vector, required by main() 73 * argv[1] 74 * ... 75 * argv[argc-1] 76 * null 77 * environ: environ[0] <-- environment variables, required by main() and getenv() 78 * environ[1] 79 * ... 80 * null 81 * _auxv: _auxv[0] <-- auxiliary vector, required by getauxval() 82 * _auxv[1] 83 * ... 84 * null 85 */ 86 87 /* assign argc and argv */ 88 argc = *sp; 89 argv = (void *)(sp + 1); 90 91 /* find environ */ 92 environ = envp = argv + argc + 1; 93 94 /* find _auxv */ 95 for (auxv = (void *)envp; *auxv++;) 96 __asm__(""); 97 _auxv = auxv; 98 99 #ifndef NOLIBC_IGNORE_ERRNO 100 if (argc > 0 && argv[0]) { 101 program_invocation_name = argv[0]; 102 program_invocation_short_name = __nolibc_program_invocation_short_name(argv[0]); 103 } 104 #endif /* NOLIBC_IGNORE_ERRNO */ 105 106 for (ctor_func = __preinit_array_start; ctor_func < __preinit_array_end; ctor_func++) 107 (*ctor_func)(argc, argv, envp); 108 for (ctor_func = __init_array_start; ctor_func < __init_array_end; ctor_func++) 109 (*ctor_func)(argc, argv, envp); 110 111 /* go to application */ 112 exitcode = _nolibc_main(argc, argv, envp); 113 114 for (dtor_func = __fini_array_end; dtor_func > __fini_array_start;) 115 (*--dtor_func)(); 116 117 exit(exitcode); 118 } 119 120 #endif /* NOLIBC_NO_RUNTIME */ 121 #endif /* _NOLIBC_CRT_H */ 122