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