1 /* Formatted output to strings. 2 Copyright (C) 2004, 2006-2012 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation; either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17 #if 1 18 # include <config.h> 19 #endif 20 21 /* Specification. */ 22 #include <stdio.h> 23 24 #include <errno.h> 25 #include <limits.h> 26 #include <stdarg.h> 27 #include <stdint.h> 28 #include <stdlib.h> 29 30 #include "vasnprintf.h" 31 32 #ifndef SIZE_MAX 33 # define SIZE_MAX ((size_t) -1) 34 #endif 35 36 /* Print formatted output to string STR. 37 Return string length of formatted string. On error, return a negative 38 value. */ 39 int 40 sprintf (char *str, const char *format, ...) 41 { 42 char *output; 43 size_t len; 44 size_t lenbuf; 45 va_list args; 46 47 /* vasnprintf fails with EOVERFLOW when the buffer size argument is larger 48 than INT_MAX (if that fits into a 'size_t' at all). 49 Also note that glibc's iconv fails with E2BIG when we pass a length that 50 is so large that str + lenbuf wraps around, i.e. 51 (uintptr_t) (str + lenbuf) < (uintptr_t) str. 52 Therefore set lenbuf = min (SIZE_MAX, INT_MAX, - (uintptr_t) str - 1). */ 53 lenbuf = (SIZE_MAX < INT_MAX ? SIZE_MAX : INT_MAX); 54 if (lenbuf > ~ (uintptr_t) str) 55 lenbuf = ~ (uintptr_t) str; 56 57 va_start (args, format); 58 output = vasnprintf (str, &lenbuf, format, args); 59 len = lenbuf; 60 va_end (args); 61 62 if (!output) 63 return -1; 64 65 if (output != str) 66 { 67 /* len is near SIZE_MAX. */ 68 free (output); 69 errno = EOVERFLOW; 70 return -1; 71 } 72 73 if (len > INT_MAX) 74 { 75 errno = EOVERFLOW; 76 return -1; 77 } 78 79 return len; 80 } 81
