strlcat.c
#include <sys/types.h>
#include <string.h>
/*
* Appends src to string dst of size dsize (unlike strncat, dsize is the
* full size of dst, not space left). At most dsize-1 characters
* will be copied. Always NUL terminates (unless dsize <= strlen(dst)).
* Returns strlen(src) + MIN(dsize, strlen(initial dst)).
* If retval >= dsize, truncation occurred.
*/
size_t
strlcat(char *dst, const char *src, size_t dsize)
{
const char *odst = dst;
const char *osrc = src;
size_t n = dsize;
size_t dlen;
/* Find the end of dst and adjust bytes left but don't go past end. */
while (n-- != 0 && *dst != '\0')
dst++;
dlen = dst - odst;
n = dsize - dlen;
if (n-- == 0)
return(dlen + strlen(src));
while (*src != '\0') {
if (n != 0) {
*dst++ = *src;
n--;
}
src++;
}
*dst = '\0';
return(dlen + (src - osrc)); /* count does not include NUL */
}
测试代码 strlcattest.c
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <setjmp.h>
#include <signal.h>
#include <unistd.h>
volatile sig_atomic_t got_signal;
sigjmp_buf jmpenv;
void
handler(int signo)
{
got_signal = signo;
siglongjmp(jmpenv, 1);
}
int
main(int argc, char *argv[])
{
char *buf, *cp, *ep;
struct sigaction sa;
size_t len, bufsize;
int failures = 0;
bufsize = getpagesize(); /* trigger guard pages easily */
buf = malloc(bufsize);
if (buf == NULL) {
fprintf(stderr, "unable to allocate memory\n");
return 1;
}
memset(buf, 'z', bufsize);
ep = buf + bufsize;
/* Test appending to an unterminated string. */
len = strlcat(buf, "abcd", bufsize);
if (len != 4 + bufsize) {
fprintf(stderr,
"strlcat: failed unterminated buffer test (1a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
for (cp = buf; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcat: failed unterminated buffer test (1b)\n");
failures++;
break;
}
}
/* Test appending to a full string. */
ep[-1] = '\0';
len = strlcat(buf, "abcd", bufsize);
if (len != 4 + bufsize - 1) {
fprintf(stderr, "strlcat: failed full buffer test (2a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
for (cp = buf; cp < ep - 1; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcat: failed full buffer test (2b)\n");
failures++;
break;
}
}
/* Test appending to an empty string. */
ep[-1] = 'z';
buf[0] = '\0';
len = strlcat(buf, "abcd", bufsize);
if (len != 4) {
fprintf(stderr, "strlcat: failed empty buffer test (3a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
if (memcmp(buf, "abcd", sizeof("abcd")) != 0) {
fprintf(stderr, "strlcat: failed empty buffer test (3b)\n");
failures++;
}
for (cp = buf + len + 1; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcat: failed empty buffer test (3c)\n");
failures++;
break;
}
}
/* Test appending to a NUL-terminated string. */
memcpy(buf, "abcd", sizeof("abcd"));
len = strlcat(buf, "efgh", bufsize);
if (len != 8) {
fprintf(stderr, "strlcat: failed empty buffer test (4a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
if (memcmp(buf, "abcdefgh", sizeof("abcdefgh")) != 0) {
fprintf(stderr, "strlcat: failed empty buffer test (4b)\n");
failures++;
}
for (cp = buf + len + 1; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcat: failed empty buffer test (4c)\n");
failures++;
break;
}
}
/*
* The following tests should result in SIGSEGV, however some
* systems may erroneously report SIGBUS.
* These tests assume that strlcat() is signal-safe.
*/
memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);
sa.sa_handler = handler;
sigaction(SIGSEGV, &sa, NULL);
sigaction(SIGBUS, &sa, NULL);
/* Test copying to a NULL buffer with non-zero size. */
got_signal = 0;
if (sigsetjmp(jmpenv, 1) == 0) {
len = strlcat(NULL, "abcd", sizeof(buf));
fprintf(stderr, "strlcat: failed NULL dst test (5a), "
"expected signal %d, got len %zu\n", SIGSEGV, len);
failures++;
} else if (got_signal != SIGSEGV) {
fprintf(stderr, "strlcat: failed NULL dst test (5b), "
"expected signal %d, got %d\n", SIGSEGV, got_signal);
failures++;
}
/* Test copying from a NULL src. */
memcpy(buf, "abcd", sizeof("abcd"));
got_signal = 0;
if (sigsetjmp(jmpenv, 1) == 0) {
len = strlcat(buf, NULL, sizeof(buf));
fprintf(stderr, "strlcat: failed NULL src test (6a), "
"expected signal %d, got len %zu\n", SIGSEGV, len);
failures++;
} else if (got_signal != SIGSEGV) {
fprintf(stderr, "strlcat: failed NULL src test (6b), "
"expected signal %d, got %d\n", SIGSEGV, got_signal);
failures++;
}
return failures;
}
strlcpy.c
#include <sys/types.h>
#include <string.h>
/*
* Copy string src to buffer dst of size dsize. At most dsize-1
* chars will be copied. Always NUL terminates (unless dsize == 0).
* Returns strlen(src); if retval >= dsize, truncation occurred.
*/
size_t
strlcpy(char *dst, const char *src, size_t dsize)
{
const char *osrc = src;
size_t nleft = dsize;
/* Copy as many bytes as will fit. */
if (nleft != 0) {
while (--nleft != 0) {
if ((*dst++ = *src++) == '\0')
break;
}
}
/* Not enough room in dst, add NUL and traverse rest of src. */
if (nleft == 0) {
if (dsize != 0)
*dst = '\0'; /* NUL-terminate dst */
while (*src++)
;
}
return(src - osrc - 1); /* count does not include NUL */
}
测试代码strlcpy.c
/* $OpenBSD: strlcpytest.c,v 1.4 2021/09/01 09:26:32 jasper Exp $ */
/*
* Copyright (c) 2014 Todd C. Miller <millert@openbsd.org>
*
* 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.
*/
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <setjmp.h>
#include <unistd.h>
volatile sig_atomic_t got_signal;
sigjmp_buf jmpenv;
void
handler(int signo)
{
got_signal = signo;
siglongjmp(jmpenv, 1);
}
int
main(int argc, char *argv[])
{
char *buf, *buf2, *cp, *ep;
struct sigaction sa;
size_t len, bufsize;
int failures = 0;
bufsize = getpagesize(); /* trigger guard pages easily */
buf = malloc(bufsize);
buf2 = malloc(bufsize);
if (buf == NULL || buf2 == NULL) {
fprintf(stderr, "unable to allocate memory\n");
return 1;
}
memset(buf, 'z', bufsize);
ep = buf + bufsize;
/* Test copying to a zero-length NULL buffer. */
len = strlcpy(NULL, "abcd", 0);
if (len != 4) {
fprintf(stderr,
"strlcpy: failed zero-length buffer test (1a)\n");
failures++;
}
/* Test copying small string to a large buffer. */
len = strlcpy(buf, "abcd", bufsize);
if (len != 4) {
fprintf(stderr, "strlcpy: failed large buffer test (2a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
if (memcmp(buf, "abcd", sizeof("abcd")) != 0) {
fprintf(stderr, "strlcpy: failed large buffer test (2b)\n");
failures++;
}
for (cp = buf + len + 1; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcpy: failed large buffer test (2c)\n");
failures++;
break;
}
}
/* Test copying large string to a small buffer. */
memset(buf, 'z', bufsize);
memset(buf2, 'x', bufsize - 1);
buf2[bufsize - 1] = '\0';
len = strlcpy(buf, buf2, bufsize / 2);
if (len != bufsize - 1) {
fprintf(stderr, "strlcpy: failed small buffer test (3a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
len = (bufsize / 2) - 1;
if (memcmp(buf, buf2, len) != 0 || buf[len] != '\0') {
fprintf(stderr, "strlcpy: failed small buffer test (3b)\n");
failures++;
}
for (cp = buf + len + 1; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcpy: failed small buffer test (3c)\n");
failures++;
break;
}
}
/* Test copying to a 1-byte buffer. */
memset(buf, 'z', bufsize);
len = strlcpy(buf, "abcd", 1);
if (len != 4) {
fprintf(stderr, "strlcpy: failed 1-byte buffer test (4a)\n");
failures++;
}
/* Make sure we only wrote where expected. */
if (buf[0] != '\0') {
fprintf(stderr, "strlcpy: failed 1-byte buffer test (4b)\n");
failures++;
}
for (cp = buf + 1; cp < ep; cp++) {
if (*cp != 'z') {
fprintf(stderr,
"strlcpy: failed 1-byte buffer test (4c)\n");
failures++;
break;
}
}
/*
* The following tests should result in SIGSEGV, however some
* systems may erroneously report SIGBUS.
* These tests assume that strlcpy() is signal-safe.
*/
memset(&sa, 0, sizeof(sa));
sigemptyset(&sa.sa_mask);
sa.sa_handler = handler;
sigaction(SIGSEGV, &sa, NULL);
sigaction(SIGBUS, &sa, NULL);
/* Test copying to a NULL buffer with non-zero size. */
got_signal = 0;
if (sigsetjmp(jmpenv, 1) == 0) {
len = strlcpy(NULL, "abcd", sizeof(buf));
fprintf(stderr, "strlcpy: failed NULL dst test (5a), "
"expected signal %d, got len %zu\n", SIGSEGV, len);
failures++;
} else if (got_signal != SIGSEGV) {
fprintf(stderr, "strlcpy: failed NULL dst test (5b), "
"expected signal %d, got %d\n", SIGSEGV, got_signal);
failures++;
}
/* Test copying from a NULL src. */
got_signal = 0;
if (sigsetjmp(jmpenv, 1) == 0) {
len = strlcpy(buf, NULL, sizeof(buf));
fprintf(stderr, "strlcpy: failed NULL src test (6a), "
"expected signal %d, got len %zu\n", SIGSEGV, len);
failures++;
} else if (got_signal != SIGSEGV) {
fprintf(stderr, "strlcpy: failed NULL src test (6b), "
"expected signal %d, got %d\n", SIGSEGV, got_signal);
failures++;
}
return failures;
}
代码来源：http://ftp.openbsd.org/pub/OpenBSD/7.0/src.tar.gz
