diff options
| author | lukem <lukem@NetBSD.org> | 1999-09-08 22:01:13 +0000 |
|---|---|---|
| committer | lukem <lukem@NetBSD.org> | 1999-09-08 22:01:13 +0000 |
| commit | 714b0ff65a482e08b017825d7aef60d33d576f3c (patch) | |
| tree | 05f4a345a4133ed76b438562b36bf5f36ca068ac /lib/libc/string | |
| parent | 5fb18dd9daa66d272b9b7657bd613fe68bd4bc8e (diff) | |
strlcpy() and strlcat() by Todd Miller <Todd.Miller@courtesan.com>, via openbsd
Diffstat (limited to 'lib/libc/string')
| -rw-r--r-- | lib/libc/string/strlcat.c | 71 | ||||
| -rw-r--r-- | lib/libc/string/strlcpy.3 | 147 | ||||
| -rw-r--r-- | lib/libc/string/strlcpy.c | 68 |
3 files changed, 286 insertions, 0 deletions
diff --git a/lib/libc/string/strlcat.c b/lib/libc/string/strlcat.c new file mode 100644 index 00000000000..599994edf5a --- /dev/null +++ b/lib/libc/string/strlcat.c @@ -0,0 +1,71 @@ +/* $OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $ */ + +/* + * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char *rcsid = "$OpenBSD: strlcat.c,v 1.2 1999/06/17 16:28:58 millert Exp $"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/types.h> +#include <string.h> + +/* + * 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 == 0). + * Returns strlen(src); if retval >= siz, truncation occurred. + */ +size_t strlcat(dst, src, siz) + char *dst; + const char *src; + size_t siz; +{ + register char *d = dst; + register const char *s = src; + register size_t n = siz; + size_t dlen; + + /* Find the end of dst and adjust bytes left but don't go past end */ + while (*d != '\0' && n-- != 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 */ +} diff --git a/lib/libc/string/strlcpy.3 b/lib/libc/string/strlcpy.3 new file mode 100644 index 00000000000..b07e30e6ea3 --- /dev/null +++ b/lib/libc/string/strlcpy.3 @@ -0,0 +1,147 @@ +.\" $OpenBSD: strlcpy.3,v 1.6 1999/09/04 02:22:46 pjanzen Exp $ +.\" +.\" Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, +.\" INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY +.\" AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +.\" THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, +.\" EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, +.\" PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; +.\" OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, +.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR +.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF +.\" ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.Dd June 22, 1998 +.Dt STRLCPY 3 +.Os +.Sh NAME +.Nm strlcpy , +.Nm strlcat +.Nd size-bounded string copying and concatenation +.Sh SYNOPSIS +.Fd #include <string.h> +.Ft size_t +.Fn strlcpy "char *dst" "const char *src" "size_t size" +.Ft size_t +.Fn strlcat "char *dst" "const char *src" "size_t size" +.Sh DESCRIPTION +The +.Fn strlcpy +and +.Fn strlcat +functions copy and concatenate strings respectively. They are designed +to be safer, more consistent, and less error prone replacements for +.Xr strncpy 3 +and +.Xr strncat 3 . +Unlike those functions, +.Fn strlcpy +and +.Fn strlcat +take the full size of the buffer (not just the length) and guarantee to +NUL-terminate the result (as long as +.Fa size +is larger than 0). Note that you should include a byte for the NUL in +.Fa size . +.Pp +The +.Fn strlcpy +function copies up to +.Fa size +- 1 characters from the NUL-terminated string +.Fa src +to +.Fa dst , +NUL-terminating the result. +.Pp +The +.Fn strlcat +function appends the NUL-terminated string +.Fa src +to the end of +.Fa dst . +It will append at most +.Fa size +- strlen(dst) - 1 bytes, NUL-terminating the result. +.Sh RETURN VALUES +The +.Fn strlcpy +and +.Fn strlcat +functions return the total length of the string they tried to +create. For +.Fn strlcpy +that means the length of +.Fa src . +For +.Fn strlcat +that means the initial length of +.Fa dst +plus +the length of +.Fa src . +While this may seem somewhat confusing it was done to make +truncation detection simple. +.Sh EXAMPLES +The following code fragment illustrates the simple case: +.Bd -literal -offset indent +char *s, *p, buf[BUFSIZ]; + +\&... + +(void)strlcpy(buf, s, sizeof(buf)); +(void)strlcat(buf, p, sizeof(buf)); +.Ed +.Pp +To detect truncation, perhaps while building a pathname, something +like the following might be used: +.Bd -literal -offset indent +char *dir, *file, pname[MAXPATHNAMELEN]; + +\&... + +if (strlcpy(pname, dir, sizeof(pname)) >= sizeof(pname)) + goto toolong; +if (strlcat(pname, file, sizeof(pname)) >= sizeof(pname)) + goto toolong; +.Ed +.Pp +Since we know how many characters we copied the first time, we can +speed things up a bit by using a copy instead on an append: +.Bd -literal -offset indent +char *dir, *file, pname[MAXPATHNAMELEN]; +size_t n; + +\&... + +n = strlcpy(pname, dir, sizeof(pname)); +if (n >= sizeof(pname)) + goto toolong; +if (strlcpy(pname + n, file, sizeof(pname) - n) >= sizeof(pname) - n) + goto toolong; +.Ed +.Pp +However, one may question the validity of such optimizations, as they +defeat the whole purpose of +.Fn strlcpy +and +.Fn strlcat . +As a matter of fact, the first version of this manual page got it wrong. +.Sh SEE ALSO +.Xr snprintf 3 , +.Xr strncat 3 , +.Xr strncpy 3 diff --git a/lib/libc/string/strlcpy.c b/lib/libc/string/strlcpy.c new file mode 100644 index 00000000000..300a28bc391 --- /dev/null +++ b/lib/libc/string/strlcpy.c @@ -0,0 +1,68 @@ +/* $OpenBSD: strlcpy.c,v 1.4 1999/05/01 18:56:41 millert Exp $ */ + +/* + * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, + * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY + * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL + * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; + * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, + * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR + * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF + * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char *rcsid = "$OpenBSD: strlcpy.c,v 1.4 1999/05/01 18:56:41 millert Exp $"; +#endif /* LIBC_SCCS and not lint */ + +#include <sys/types.h> +#include <string.h> + +/* + * 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(dst, src, siz) + char *dst; + const char *src; + size_t siz; +{ + register char *d = dst; + register const char *s = src; + register size_t n = siz; + + /* Copy as many bytes as will fit */ + if (n != 0 && --n != 0) { + do { + if ((*d++ = *s++) == 0) + break; + } while (--n != 0); + } + + /* 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 */ +} |
