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 __attribute__((weak)) _start_c(long * sp)17 void _start_c(long *sp) 18 { 19 long argc; 20 char **argv; 21 char **envp; 22 const unsigned long *auxv; 23 /* silence potential warning: conflicting types for 'main' */ 24 int _nolibc_main(int, char **, char **) __asm__ ("main"); 25 26 /* initialize stack protector */ 27 __stack_chk_init(); 28 29 /* 30 * sp : argc <-- argument count, required by main() 31 * argv: argv[0] <-- argument vector, required by main() 32 * argv[1] 33 * ... 34 * argv[argc-1] 35 * null 36 * environ: environ[0] <-- environment variables, required by main() and getenv() 37 * environ[1] 38 * ... 39 * null 40 * _auxv: _auxv[0] <-- auxiliary vector, required by getauxval() 41 * _auxv[1] 42 * ... 43 * null 44 */ 45 46 /* assign argc and argv */ 47 argc = *sp; 48 argv = (void *)(sp + 1); 49 50 /* find environ */ 51 environ = envp = argv + argc + 1; 52 53 /* find _auxv */ 54 for (auxv = (void *)envp; *auxv++;) 55 ; 56 _auxv = auxv; 57 58 /* go to application */ 59 exit(_nolibc_main(argc, argv, envp)); 60 } 61 62 #endif /* _NOLIBC_CRT_H */ 63