1 /* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ 2 /* util/support/printf.c */ 3 /* 4 * Copyright 2003, 2004, 2005, 2007, 2008 Massachusetts Institute of 5 * Technology. All Rights Reserved. 6 * 7 * Export of this software from the United States of America may 8 * require a specific license from the United States Government. 9 * It is the responsibility of any person or organization contemplating 10 * export to obtain such a license before exporting. 11 * 12 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 13 * distribute this software and its documentation for any purpose and 14 * without fee is hereby granted, provided that the above copyright 15 * notice appear in all copies and that both that copyright notice and 16 * this permission notice appear in supporting documentation, and that 17 * the name of M.I.T. not be used in advertising or publicity pertaining 18 * to distribution of the software without specific, written prior 19 * permission. Furthermore if you modify this software you must label 20 * your software as modified software and not distribute it in such a 21 * fashion that it might be confused with the original M.I.T. software. 22 * M.I.T. makes no representations about the suitability of 23 * this software for any purpose. It is provided "as is" without express 24 * or implied warranty. 25 */ 26 27 /* Provide {,v}asprintf for platforms that don't have them. */ 28 29 #include "k5-platform.h" 30 31 /* On error: BSD: Set *ret to NULL. GNU: *ret is undefined. 32 33 Since we want to be able to use the GNU version directly, we need 34 provide only the weaker guarantee in this version. */ 35 int 36 krb5int_vasprintf(char **ret, const char *format, va_list ap) 37 { 38 va_list ap2; 39 char *str = NULL, *nstr; 40 size_t len = 80; 41 int len2; 42 43 while (1) { 44 if (len >= INT_MAX || len == 0) 45 goto fail; 46 nstr = realloc(str, len); 47 if (nstr == NULL) 48 goto fail; 49 str = nstr; 50 va_copy(ap2, ap); 51 len2 = vsnprintf(str, len, format, ap2); 52 va_end(ap2); 53 /* ISO C vsnprintf returns the needed length. Some old 54 vsnprintf implementations return -1 on truncation. */ 55 if (len2 < 0) { 56 /* Don't know how much space we need, just that we didn't 57 supply enough; get a bigger buffer and try again. */ 58 if (len <= SIZE_MAX/2) 59 len *= 2; 60 else if (len < SIZE_MAX) 61 len = SIZE_MAX; 62 else 63 goto fail; 64 } else if ((unsigned int) len2 >= SIZE_MAX) { 65 /* Need more space than we can request. */ 66 goto fail; 67 } else if ((size_t) len2 >= len) { 68 /* Need more space, but we know how much. */ 69 len = (size_t) len2 + 1; 70 } else { 71 /* Success! */ 72 break; 73 } 74 } 75 /* We might've allocated more than we need, if we're still using 76 the initial guess, or we got here by doubling. */ 77 if ((size_t) len2 < len - 1) { 78 nstr = realloc(str, (size_t) len2 + 1); 79 if (nstr) 80 str = nstr; 81 } 82 *ret = str; 83 return len2; 84 85 fail: 86 free(str); 87 return -1; 88 } 89 90 int 91 krb5int_asprintf(char **ret, const char *format, ...) 92 { 93 va_list ap; 94 int n; 95 96 va_start(ap, format); 97 n = krb5int_vasprintf(ret, format, ap); 98 va_end(ap); 99 return n; 100 } 101