compat_strlcpy.c

   1 /*      $Id: compat_strlcpy.c,v 1.6 2020/06/15 20:49:57 schwarze Exp $  */
   2 /*      $OpenBSD: strlcpy.c,v 1.16 2019/01/25 00:19:25 millert Exp $    */
   3
   4 /*
   5  * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
   6  *
   7  * Permission to use, copy, modify, and distribute this software for any
   8  * purpose with or without fee is hereby granted, provided that the above
   9  * copyright notice and this permission notice appear in all copies.
  10  *
  11  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  12  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  13  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  14  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  15  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  16  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  17  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  18  */
  19 #include "config.h"
  20
  21 #include <sys/types.h>
  22 #include <string.h>
  23
  24 /*
  25  * Copy string src to buffer dst of size dsize.  At most dsize-1
  26  * chars will be copied.  Always NUL terminates (unless dsize == 0).
  27  * Returns strlen(src); if retval >= dsize, truncation occurred.
  28  */
  29 size_t
  30 strlcpy(char *dst, const char *src, size_t dsize)
  31 {
  32         const char *osrc = src;
  33         size_t nleft = dsize;
  34
  35         /* Copy as many bytes as will fit. */
  36         if (nleft != 0) {
  37                 while (--nleft != 0) {
  38                         if ((*dst++ = *src++) == '\0')
  39                                 break;
  40                 }
  41         }
  42
  43         /* Not enough room in dst, add NUL and traverse rest of src. */
  44         if (nleft == 0) {
  45                 if (dsize != 0)
  46                         *dst = '\0';            /* NUL-terminate dst */
  47                 while (*src++)
  48                         ;
  49         }
  50
  51         return(src - osrc - 1); /* count does not include NUL */
  52 }