1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)strcpy.3 8.1 (Berkeley) 6/4/93 33.\" $NetBSD: strcpy.3,v 1.24 2023/08/11 09:39:39 riastradh Exp $ 34.\" 35.Dd August 11, 2023 36.Dt STRCPY 3 37.Os 38.Sh NAME 39.Nm stpcpy , 40.Nm strcpy 41.Nd copy strings 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft char * 47.Fn stpcpy "char * restrict dst" "const char * restrict src" 48.Ft char * 49.Fn strcpy "char * restrict dst" "const char * restrict src" 50.Sh DESCRIPTION 51The 52.Fn stpcpy 53and 54.Fn strcpy 55functions 56copy the string 57.Fa src 58to 59.Fa dst , 60including the terminating 61.Ql \e0 62character. 63.Pp 64The strings 65.Fa src 66and 67.Fa dst 68may not overlap. 69The string 70.Fa src 71must be terminated by a 72.Ql \e0 73character. 74The memory for 75.Fa dst 76must have space for 77.Fn strlen src Li "+ 1" 78bytes. 79.Sh RETURN VALUES 80The 81.Fn strcpy 82function returns 83.Fa dst . 84.Pp 85The 86.Fn stpcpy 87function returns a pointer to the terminating 88.Ql \e0 89character of 90.Fa dst . 91.Sh SEE ALSO 92.Xr bcopy 3 , 93.Xr memccpy 3 , 94.Xr memcpy 3 , 95.Xr memmove 3 , 96.Xr strlcpy 3 , 97.Xr strncpy 3 , 98.Xr wcscpy 3 99.Sh STANDARDS 100The 101.Fn strcpy 102function conforms to 103.St -isoC-99 . 104.Pp 105The 106.Fn stpcpy 107function conforms to 108.St -p1003.1-2008 . 109.Sh HISTORY 110The 111.Fn stpcpy 112function first appeared in 113.Nx 6.0 . 114.Sh SECURITY CONSIDERATIONS 115The 116.Fn strcpy 117and 118.Fn stpcpy 119functions copy until a 120.Ql \e0 121terminator without any bounds checks on the size of the input or output 122buffers. 123If the input buffer is missing a 124.Ql \e0 125terminator, or the input string is longer than the output buffer, this 126can lead to crashes or security vulnerabilities from buffer overruns, 127including disclosure of secrets in memory and arbitrary code 128execution. 129