1.\" $NetBSD: openpam_readword.3,v 1.2 2013/07/20 21:40:04 wiz Exp $ 2.\" 3.\"- 4.\" Copyright (c) 2001-2003 Networks Associates Technology, Inc. 5.\" Copyright (c) 2004-2011 Dag-Erling Smørgrav 6.\" All rights reserved. 7.\" 8.\" This software was developed for the FreeBSD Project by ThinkSec AS and 9.\" Network Associates Laboratories, the Security Research Division of 10.\" Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 11.\" ("CBOSS"), as part of the DARPA CHATS research program. 12.\" 13.\" Redistribution and use in source and binary forms, with or without 14.\" modification, are permitted provided that the following conditions 15.\" are met: 16.\" 1. Redistributions of source code must retain the above copyright 17.\" notice, this list of conditions and the following disclaimer. 18.\" 2. Redistributions in binary form must reproduce the above copyright 19.\" notice, this list of conditions and the following disclaimer in the 20.\" documentation and/or other materials provided with the distribution. 21.\" 3. The name of the author may not be used to endorse or promote 22.\" products derived from this software without specific prior written 23.\" permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 26.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 29.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35.\" SUCH DAMAGE. 36.\" 37.\" Id 38.\" 39.Dd May 26, 2012 40.Dt OPENPAM_READWORD 3 41.Os 42.Sh NAME 43.Nm openpam_readword 44.Nd read a word from a file, respecting shell quoting rules 45.Sh LIBRARY 46.Lb libpam 47.Sh SYNOPSIS 48.In sys/types.h 49.In stdio.h 50.In security/pam_appl.h 51.In security/openpam.h 52.Ft "char *" 53.Fn openpam_readword "FILE *f" "int *lineno" "size_t *lenp" 54.Sh DESCRIPTION 55The 56.Fn openpam_readword 57function reads the next word from a file, and 58returns it in a NUL-terminated buffer allocated with 59.Xr malloc 3 . 60.Pp 61A word is a sequence of non-whitespace characters. 62However, whitespace characters can be included in a word if quoted or 63escaped according to the following rules: 64.Bl -bullet 65.It 66An unescaped single or double quote introduces a quoted string, 67which ends when the same quote character is encountered a second 68time. 69The quotes themselves are stripped. 70.It 71Within a single- or double-quoted string, all whitespace characters, 72including the newline character, are preserved as-is. 73.It 74Outside a quoted string, a backslash escapes the next character, 75which is preserved as-is, unless that character is a newline, in 76which case it is discarded and reading continues at the beginning of 77the next line as if the backslash and newline had not been there. 78In all cases, the backslash itself is discarded. 79.It 80Within a single-quoted string, double quotes and backslashes are 81preserved as-is. 82.It 83Within a double-quoted string, a single quote is preserved as-is, 84and a backslash is preserved as-is unless used to escape a double 85quote. 86.El 87.Pp 88In addition, if the first non-whitespace character on the line is a 89hash character (#), the rest of the line is discarded. 90If a hash character occurs within a word, however, it is preserved 91as-is. 92A backslash at the end of a comment does cause line continuation. 93.Pp 94If 95.Fa lineno 96is not 97.Dv NULL , 98the integer variable it points to is 99incremented every time a quoted or escaped newline character is read. 100.Pp 101If 102.Fa lenp 103is not 104.Dv NULL , 105the length of the word (after quotes and 106backslashes have been removed) is stored in the variable it points to. 107.Sh RETURN VALUES 108If successful, the 109.Fn openpam_readword 110function returns a pointer to a 111dynamically allocated NUL-terminated string containing the first word 112encountered on the line. 113.Pp 114The caller is responsible for releasing the returned buffer by passing 115it to 116.Xr free 3 . 117.Pp 118If 119.Fn openpam_readword 120reaches the end of the line or file before any 121characters are copied to the word, it returns 122.Dv NULL . 123In the former 124case, the newline is pushed back to the file. 125.Pp 126If 127.Fn openpam_readword 128reaches the end of the file while a quote or 129backslash escape is in effect, it sets 130.Va errno 131to 132.Dv EINVAL 133and returns 134.Dv NULL . 135.Sh IMPLEMENTATION NOTES 136The parsing rules are intended to be equivalent to the normal POSIX 137shell quoting rules. 138Any discrepancy is a bug and should be reported to the author along 139with sample input that can be used to reproduce the error. 140.Pp 141.Sh SEE ALSO 142.Xr openpam_readline 3 , 143.Xr openpam_readlinev 3 , 144.Xr pam 3 145.Sh STANDARDS 146The 147.Fn openpam_readword 148function is an OpenPAM extension. 149.Sh AUTHORS 150The 151.Fn openpam_readword 152function and this manual page were 153developed by 154.An Dag-Erling Sm\(/orgrav Aq Mt des@des.no . 155