snprintftest.c

来自「OpenSSH 是 SSH （Secure SHell） 协议的免费开源实现。它」· C语言 代码 · 共 74 行

/*
 * Copyright (c) 2005 Darren Tucker
 * Copyright (c) 2005 Damien Miller
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#define BUFSZ 2048

#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>

static int failed = 0;

static void
fail(const char *m)
{
	fprintf(stderr, "snprintftest: %s\n", m);
	failed = 1;
}

int x_snprintf(char *str, size_t count, const char *fmt, ...)
{
	size_t ret;
	va_list ap;

	va_start(ap, fmt);
	ret = vsnprintf(str, count, fmt, ap);
	va_end(ap);
	return ret;
}

int
main(void)
{
	char b[5];
	char *src;

	snprintf(b,5,"123456789");
	if (b[4] != '\0')
		fail("snprintf does not correctly terminate long strings");

	/* check for read overrun on unterminated string */
	if ((src = malloc(BUFSZ)) == NULL) {
		fail("malloc failed");
	} else {
		memset(src, 'a', BUFSZ);
		snprintf(b, sizeof(b), "%.*s", 1, src);
		if (strcmp(b, "a") != 0)
			fail("failed with length limit '%%.s'");
	}

	/* check that snprintf and vsnprintf return sane values */
	if (snprintf(b, 1, "%s %d", "hello", 12345) != 11)
		fail("snprintf does not return required length");
	if (x_snprintf(b, 1, "%s %d", "hello", 12345) != 11)
		fail("vsnprintf does not return required length");

	return failed;
}