1/* Checking gets. 2 Copyright (C) 2005-2022 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify it under 7the terms of the GNU General Public License as published by the Free 8Software Foundation; either version 3, or (at your option) any later 9version. 10 11In addition to the permissions in the GNU General Public License, the 12Free Software Foundation gives you unlimited permission to link the 13compiled version of this file into combinations with other programs, 14and to distribute those combinations without any restriction coming 15from the use of this file. (The General Public License restrictions 16do apply in other respects; for example, they cover modification of 17the file, and distribution when not linked into a combine 18executable.) 19 20GCC is distributed in the hope that it will be useful, but WITHOUT ANY 21WARRANTY; without even the implied warranty of MERCHANTABILITY or 22FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 23for more details. 24 25Under Section 7 of GPL version 3, you are granted additional 26permissions described in the GCC Runtime Library Exception, version 273.1, as published by the Free Software Foundation. 28 29You should have received a copy of the GNU General Public License and 30a copy of the GCC Runtime Library Exception along with this program; 31see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 32<http://www.gnu.org/licenses/>. */ 33 34 35#include "config.h" 36#include <ssp/ssp.h> 37#include <stdarg.h> 38#ifdef HAVE_STDLIB_H 39# include <stdlib.h> 40#endif 41#ifdef HAVE_ALLOCA_H 42# include <alloca.h> 43#endif 44#ifdef HAVE_LIMITS_H 45# include <limits.h> 46#endif 47#ifdef HAVE_STDIO_H 48# include <stdio.h> 49#endif 50#ifdef HAVE_STRING_H 51# include <string.h> 52#endif 53 54#if !(!defined __USE_ISOC11 \ 55 || (defined __cplusplus && __cplusplus <= 201103L)) 56extern char *gets (char *); 57#endif 58 59extern void __chk_fail (void) __attribute__((__noreturn__)); 60 61char * 62__gets_chk (char *s, size_t slen) 63{ 64 char *ret, *buf; 65 66 if (slen >= (size_t) INT_MAX) 67 return gets (s); 68 69 if (slen <= 8192) 70 buf = alloca (slen + 1); 71 else 72 buf = malloc (slen + 1); 73 if (buf == NULL) 74 return gets (s); 75 76 ret = fgets (buf, (int) (slen + 1), stdin); 77 if (ret != NULL) 78 { 79 size_t len = strlen (buf); 80 if (len > 0 && buf[len - 1] == '\n') 81 --len; 82 if (len == slen) 83 __chk_fail (); 84 memcpy (s, buf, len); 85 s[len] = '\0'; 86 ret = s; 87 } 88 89 if (slen > 8192) 90 free (buf); 91 return ret; 92} 93