.\" 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. All advertising materials mentioning features or use of this software
-.\" must display the following acknowledgement:
-.\" This product includes software developed by the University of
-.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
.\" SUCH DAMAGE.
.\"
.\" @(#)strcpy.3 8.1 (Berkeley) 6/4/93
-.\" $FreeBSD: src/lib/libc/string/strcpy.3,v 1.11 2001/10/01 16:09:00 ru Exp $
+.\" $FreeBSD: src/lib/libc/string/strcpy.3,v 1.28 2009/04/07 13:42:53 trasz Exp $
.\"
-.Dd August 9, 2001
+.Dd February 28, 2009
.Dt STRCPY 3
.Os
.Sh NAME
-.Nm strcpy , strncpy
+.Nm stpcpy, stpncpy, strcpy , strncpy
.Nd copy strings
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft char *
-.Fn strcpy "char *dst" "const char *src"
+.Fo stpcpy
+.Fa "char *s1"
+.Fa "const char *s2"
+.Fc
.Ft char *
-.Fn strncpy "char *dst" "const char *src" "size_t len"
+.Fo stpncpy
+.Fa "char *restrict s1"
+.Fa "const char *restrict s2"
+.Fa "size_t n"
+.Fc
+.Ft char *
+.Fo strcpy
+.Fa "char *restrict s1"
+.Fa "const char *restrict s2"
+.Fc
+.Ft char *
+.Fo strncpy
+.Fa "char *restrict s1"
+.Fa "const char *restrict s2"
+.Fa "size_t n"
+.Fc
.Sh DESCRIPTION
The
+.Fn stpcpy
+and
.Fn strcpy
-function
-copies the string
-.Fa src
+functions
+copy the string
+.Fa s2
to
-.Fa dst
+.Fa s1
(including the terminating
.Ql \e0
character).
.Pp
The
+.Fn stpncpy
+and
.Fn strncpy
-function copies not more than
-.Fa len
+functions copy at most
+.Fa n
characters from
-.Fa src
+.Fa s2
into
-.Fa dst ,
-appending
-.Ql \e0
-characters if
-.Fa src
+.Fa s1 .
+If
+.Fa s2
is less than
-.Fa len
-characters long, and
+.Fa n
+characters long,
+the remainder of
+.Fa s1
+is filled with
+.Ql \e0
+characters.
+Otherwise,
+.Fa s1
+is
.Em not
-terminating
-.Fa dst
-otherwise.
+terminated.
+.Pp
+The source and destination strings should not overlap, as the
+behavior is undefined.
.Sh RETURN VALUES
The
.Fn strcpy
.Fn strncpy
functions
return
-.Fa dst .
+.Fa s1 .
+The
+.Fn stpcpy
+and
+.Fn stpncpy
+functions return a pointer to the terminating
+.Ql \e0
+character of
+.Fa s1 .
+If
+.Fn stpncpy
+does not terminate
+.Fa s1
+with a
+.Dv NUL
+character, it instead returns a pointer to
+.Li s1[n]
+(which does not necessarily refer to a valid memory location.)
.Sh EXAMPLES
The following sets
.Va chararray
.Em not
.Tn NUL
terminate
-.Va chararray
+.Va chararray ,
because the length of the source string is greater than or equal
-to the length parameter.
+to the length argument.
.Pp
The following copies as many characters from
.Va input
as shown in the following example:
.Pp
.Dl "(void)strlcpy(buf, input, sizeof(buf));"
+.Sh SECURITY CONSIDERATIONS
+The
+.Fn strcpy ,
+.Fn strncpy ,
+.Fn stpcpy ,
+and
+.Fn stpncpy
+functions are easily misused in a manner which enables malicious users
+to arbitrarily change a running program's functionality through a
+buffer overflow attack.
+(See
+the FSA
+and
+.Sx EXAMPLES . )
.Pp
-Note that because
+It is recommended that
+.Xr strlcpy 3
+be used instead as a way to avoid such problems.
.Xr strlcpy 3
-is not defined in any standards, it should
-only be used when portability is not a concern.
+is not defined in any standards, but it has been adopted by most major libc implementations.
.Sh SEE ALSO
.Xr bcopy 3 ,
.Xr memccpy 3 ,
.Xr memcpy 3 ,
.Xr memmove 3 ,
-.Xr strlcpy 3
+.Xr strlcpy 3 ,
+.Xr wcscpy 3
.Sh STANDARDS
The
.Fn strcpy
functions
conform to
.St -isoC .
+The
+.Fn stpcpy
+and
+.Fn stpncpy
+functions conform to
+.St -p1003.1-2008 .
+.Sh HISTORY
+The
+.Fn stpcpy
+function first appeared in
+.Fx 4.4 ,
+and
+.Fn stpncpy
+was added in
+.Fx 8.0 .
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