xref: /freebsd/crypto/krb5/src/util/support/strlcpy.c (revision b670c9bafc0e31c7609969bf374b2e80bdc00211)
1 /* -*- mode: c; c-file-style: "bsd"; indent-tabs-mode: t -*- */
2 /*
3  * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
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 
18 /* Provide strlcpy and strlcat for platforms that don't have them. */
19 
20 #include "k5-platform.h"
21 #include <sys/types.h>
22 #include <string.h>
23 
24 /*
25  * Copy src to string dst of size siz.  At most siz-1 characters
26  * will be copied.  Always NUL terminates (unless siz == 0).
27  * Returns strlen(src); if retval >= siz, truncation occurred.
28  */
29 size_t
30 krb5int_strlcpy(char *dst, const char *src, size_t siz)
31 {
32 	char *d = dst;
33 	const char *s = src;
34 	size_t n = siz;
35 
36 	/* Copy as many bytes as will fit */
37 	if (n != 0) {
38 		while (--n != 0) {
39 			if ((*d++ = *s++) == '\0')
40 				break;
41 		}
42 	}
43 
44 	/* Not enough room in dst, add NUL and traverse rest of src */
45 	if (n == 0) {
46 		if (siz != 0)
47 			*d = '\0';		/* NUL-terminate dst */
48 		while (*s++)
49 			;
50 	}
51 
52 	return(s - src - 1);	/* count does not include NUL */
53 }
54 
55 /*
56  * Appends src to string dst of size siz (unlike strncat, siz is the
57  * full size of dst, not space left).  At most siz-1 characters
58  * will be copied.  Always NUL terminates (unless siz <= strlen(dst)).
59  * Returns strlen(src) + MIN(siz, strlen(initial dst)).
60  * If retval >= siz, truncation occurred.
61  */
62 size_t
63 krb5int_strlcat(char *dst, const char *src, size_t siz)
64 {
65 	char *d = dst;
66 	const char *s = src;
67 	size_t n = siz;
68 	size_t dlen;
69 
70 	/* Find the end of dst and adjust bytes left but don't go past end */
71 	while (n-- != 0 && *d != '\0')
72 		d++;
73 	dlen = d - dst;
74 	n = siz - dlen;
75 
76 	if (n == 0)
77 		return(dlen + strlen(s));
78 	while (*s != '\0') {
79 		if (n != 1) {
80 			*d++ = *s;
81 			n--;
82 		}
83 		s++;
84 	}
85 	*d = '\0';
86 
87 	return(dlen + (s - src));	/* count does not include NUL */
88 }
89