1/* Checking gets. 2 Copyright (C) 2005 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 2, 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 25You should have received a copy of the GNU General Public License 26along with GCC; see the file COPYING. If not, write to the Free 27Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2802110-1301, USA. */ 29 30/* As a special exception, if you link this library with files compiled with 31 GCC to produce an executable, this does not cause the resulting executable 32 to be covered by the GNU General Public License. This exception does not 33 however invalidate any other reasons why the executable file might be 34 covered by the GNU General Public License. */ 35 36#include "config.h" 37#include <ssp/ssp.h> 38#include <stdarg.h> 39#ifdef HAVE_STDLIB_H 40# include <stdlib.h> 41#endif 42#ifdef HAVE_ALLOCA_H 43# include <alloca.h> 44#endif 45#ifdef HAVE_LIMITS_H 46# include <limits.h> 47#endif 48#ifdef HAVE_STDIO_H 49# include <stdio.h> 50#endif 51#ifdef HAVE_STRING_H 52# include <string.h> 53#endif 54 55extern void __chk_fail (void) __attribute__((__noreturn__)); 56 57char * 58__gets_chk (char *s, size_t slen) 59{ 60 char *ret, *buf; 61 62 if (slen >= (size_t) INT_MAX) 63 return gets (s); 64 65 if (slen <= 8192) 66 buf = alloca (slen + 1); 67 else 68 buf = malloc (slen + 1); 69 if (buf == NULL) 70 return gets (s); 71 72 ret = fgets (buf, (int) (slen + 1), stdin); 73 if (ret != NULL) 74 { 75 size_t len = strlen (buf); 76 if (len > 0 && buf[len - 1] == '\n') 77 --len; 78 if (len == slen) 79 __chk_fail (); 80 memcpy (s, buf, len); 81 s[len] = '\0'; 82 ret = s; 83 } 84 85 if (slen > 8192) 86 free (buf); 87 return ret; 88} 89