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Diffstat (limited to 'lib/libc/string/strcpy.3')
| -rw-r--r-- | lib/libc/string/strcpy.3 | 212 |
1 files changed, 212 insertions, 0 deletions
diff --git a/lib/libc/string/strcpy.3 b/lib/libc/string/strcpy.3 new file mode 100644 index 000000000000..4d4a1ee7b3ce --- /dev/null +++ b/lib/libc/string/strcpy.3 @@ -0,0 +1,212 @@ +.\" Copyright (c) 1990, 1991, 1993 +.\" The Regents of the University of California. All rights reserved. +.\" +.\" This code is derived from software contributed to Berkeley by +.\" Chris Torek and the American National Standards Committee X3, +.\" on Information Processing Systems. +.\" +.\" 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. 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. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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. +.\" +.\" @(#)strcpy.3 8.1 (Berkeley) 6/4/93 +.\" $FreeBSD$ +.\" +.Dd February 28, 2009 +.Dt STRCPY 3 +.Os +.Sh NAME +.Nm stpcpy, stpncpy, strcpy , strncpy +.Nd copy strings +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In string.h +.Ft char * +.Fn stpcpy "char * restrict dst" "const char * restrict src" +.Ft char * +.Fn stpncpy "char * restrict dst" "const char * restrict src" "size_t len" +.Ft char * +.Fn strcpy "char * restrict dst" "const char * restrict src" +.Ft char * +.Fn strncpy "char * restrict dst" "const char * restrict src" "size_t len" +.Sh DESCRIPTION +The +.Fn stpcpy +and +.Fn strcpy +functions +copy the string +.Fa src +to +.Fa dst +(including the terminating +.Ql \e0 +character.) +.Pp +The +.Fn stpncpy +and +.Fn strncpy +functions copy at most +.Fa len +characters from +.Fa src +into +.Fa dst . +If +.Fa src +is less than +.Fa len +characters long, +the remainder of +.Fa dst +is filled with +.Ql \e0 +characters. +Otherwise, +.Fa dst +is +.Em not +terminated. +.Sh RETURN VALUES +The +.Fn strcpy +and +.Fn strncpy +functions +return +.Fa dst . +The +.Fn stpcpy +and +.Fn stpncpy +functions return a pointer to the terminating +.Ql \e0 +character of +.Fa dst . +If +.Fn stpncpy +does not terminate +.Fa dst +with a +.Dv NUL +character, it instead returns a pointer to +.Li dst[n] +(which does not necessarily refer to a valid memory location.) +.Sh EXAMPLES +The following sets +.Va chararray +to +.Dq Li abc\e0\e0\e0 : +.Bd -literal -offset indent +char chararray[6]; + +(void)strncpy(chararray, "abc", sizeof(chararray)); +.Ed +.Pp +The following sets +.Va chararray +to +.Dq Li abcdef : +.Bd -literal -offset indent +char chararray[6]; + +(void)strncpy(chararray, "abcdefgh", sizeof(chararray)); +.Ed +.Pp +Note that it does +.Em not +.Tn NUL +terminate +.Va chararray +because the length of the source string is greater than or equal +to the length argument. +.Pp +The following copies as many characters from +.Va input +to +.Va buf +as will fit and +.Tn NUL +terminates the result. +Because +.Fn strncpy +does +.Em not +guarantee to +.Tn NUL +terminate the string itself, this must be done explicitly. +.Bd -literal -offset indent +char buf[1024]; + +(void)strncpy(buf, input, sizeof(buf) - 1); +buf[sizeof(buf) - 1] = '\e0'; +.Ed +.Pp +This could be better achieved using +.Xr strlcpy 3 , +as shown in the following example: +.Pp +.Dl "(void)strlcpy(buf, input, sizeof(buf));" +.Pp +Note that because +.Xr strlcpy 3 +is not defined in any standards, it should +only be used when portability is not a concern. +.Sh SEE ALSO +.Xr bcopy 3 , +.Xr memccpy 3 , +.Xr memcpy 3 , +.Xr memmove 3 , +.Xr strlcpy 3 , +.Xr wcscpy 3 +.Sh STANDARDS +The +.Fn strcpy +and +.Fn strncpy +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 . +.Sh SECURITY CONSIDERATIONS +The +.Fn strcpy +function is easily misused in a manner which enables malicious users +to arbitrarily change a running program's functionality through a +buffer overflow attack. |