githubmirror/redis

src/strl.c
81 строка2 KB
ranshid
Avoid using unsafe C functions (#10932)
18 июл 2022, 10:56
18 июл 2022, 10:56eacca72
/*
 * Copyright (c) 1998, 2015 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 <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
redis_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 */
}

/*
 * 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
redis_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 */
}