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