strlcpy和strlcat

strncpy 等主要的问题还是虽然不会溢出，但是满了就不给缓冲区添加0结束符了，以前在项目里面自己还写了个 safe_strcpy 现在发现早就有了

 

http://blog.csdn.net/linyt/article/details/4383328

 

找了一下，代码可以在 libbsd 里面有

 

 

/*
 * Appends src to string dst of size siz (unlike strncat, siz is the
 * full size of dst, not space left).  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
 * Returns strlen(src) + MIN(siz, strlen(initial dst)).
 * If retval >= siz, truncation occurred.
 */
size_t
strlcat( char  *dst,  const  char  *src,  size_t  siz)
{
        char  *d = dst;
        const  char  *s = src;
        size_t  n = siz;
        size_t  dlen;

        /* Find the end of dst and adjust bytes left but don't go past end */
        while  (n-- != 0 && *d !=  '\0' )
                d++;
        dlen = d - dst;
        n = siz - dlen;

        if  (n == 0)
                return (dlen +  strlen (s));
        while  (*s !=  '\0' ) {
                if  (n != 1) {
                        *d++ = *s;
                        n--;
                }
                s++;
        }
        *d =  '\0' ;

        return (dlen + (s - src));        /* count does not include NUL */
}

/*
 * Copy src to string dst of size siz.  At most siz-1 characters
 * will be copied.  Always NUL terminates (unless siz == 0).
 * Returns strlen(src); if retval >= siz, truncation occurred.
 */
size_t
strlcpy( char  *dst,  const  char  *src,  size_t  siz)
{
        char  *d = dst;
        const  char  *s = src;
        size_t  n = siz;

        /* Copy as many bytes as will fit */
        if  (n != 0) {
                while  (--n != 0) {
                        if  ((*d++ = *s++) ==  '\0' )
                                break ;
                }
        }

        /* Not enough room in dst, add NUL and traverse rest of src */
        if  (n == 0) {
                if  (siz != 0)
                        *d =  '\0' ;               /* NUL-terminate dst */
                while  (*s++)
                        ;
        }

        return (s - src - 1);     /* count does not include NUL */
}