| 1 | /* $OpenBSD: snprintf.c,v 1.16 2009/10/22 01:23:16 guenther Exp $ */ |
| 2 | /* |
| 3 | * SPDX-License-Identifier: BSD-3-Clause |
| 4 | * |
| 5 | * Copyright (C) 1990, 1993 |
| 6 | * The Regents of the University of California. All rights reserved. |
| 7 | * |
| 8 | * This code is derived from software contributed to Berkeley by |
| 9 | * Chris Torek. |
| 10 | */ |
| 11 | |
| 12 | #include <limits.h> |
| 13 | #include <stddef.h> |
| 14 | #include <stdio.h> |
| 15 | #include <string.h> |
| 16 | #include <stdarg.h> |
| 17 | #include "local.h" |
| 18 | #include "common/safe-snprintf.h" |
| 19 | |
| 20 | #define DUMMY_LEN 1 |
| 21 | |
| 22 | int ust_safe_vsnprintf(char *str, size_t n, const char *fmt, va_list ap) |
| 23 | { |
| 24 | int ret; |
| 25 | char dummy[DUMMY_LEN]; |
| 26 | LTTNG_UST_LFILE f; |
| 27 | struct __lttng_ust_sfileext fext; |
| 28 | |
| 29 | /* While snprintf(3) specifies size_t stdio uses an int internally */ |
| 30 | if (n > INT_MAX) |
| 31 | n = INT_MAX; |
| 32 | /* Stdio internals do not deal correctly with zero length buffer */ |
| 33 | if (n == 0) { |
| 34 | str = dummy; |
| 35 | n = DUMMY_LEN; |
| 36 | } |
| 37 | _FILEEXT_SETUP(&f, &fext); |
| 38 | f._file = -1; |
| 39 | f._flags = __SWR | __SSTR; |
| 40 | f._bf._base = f._p = (unsigned char *)str; |
| 41 | f._bf._size = f._w = n - 1; |
| 42 | ret = ust_safe_vfprintf(&f, fmt, ap); |
| 43 | *f._p = '\0'; |
| 44 | return (ret); |
| 45 | } |
| 46 | |
| 47 | int ust_safe_snprintf(char *str, size_t n, const char *fmt, ...) |
| 48 | { |
| 49 | va_list ap; |
| 50 | int ret; |
| 51 | |
| 52 | va_start(ap, fmt); |
| 53 | ret = ust_safe_vsnprintf(str, n, fmt, ap); |
| 54 | va_end(ap); |
| 55 | |
| 56 | return ret; |
| 57 | } |