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strlcpy.c 1.6 KB

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