xref: /freebsd/contrib/openpam/lib/libpam/openpam_readline.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /*-
2  * Copyright (c) 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  * $OpenPAM: openpam_readline.c 938 2017-04-30 21:34:42Z des $
36  */
37 
38 #ifdef HAVE_CONFIG_H
39 # include "config.h"
40 #endif
41 
42 #include <stdio.h>
43 #include <stdlib.h>
44 
45 #include <security/pam_appl.h>
46 
47 #include "openpam_impl.h"
48 
49 #define MIN_LINE_LENGTH 128
50 
51 /*
52  * OpenPAM extension
53  *
54  * Read a line from a file.
55  */
56 
57 char *
58 openpam_readline(FILE *f, int *lineno, size_t *lenp)
59 {
60 	char *line;
61 	size_t len, size;
62 	int ch;
63 
64 	line = NULL;
65 	if (openpam_straddch(&line, &size, &len, 0) != 0)
66 		return (NULL);
67 	for (;;) {
68 		ch = fgetc(f);
69 		/* strip comment */
70 		if (ch == '#') {
71 			do {
72 				ch = fgetc(f);
73 			} while (ch != EOF && ch != '\n');
74 		}
75 		/* eof */
76 		if (ch == EOF) {
77 			/* done */
78 			break;
79 		}
80 		/* eol */
81 		if (ch == '\n') {
82 			if (lineno != NULL)
83 				++*lineno;
84 			/* skip blank lines */
85 			if (len == 0)
86 				continue;
87 			/* continuation */
88 			if (line[len - 1] == '\\') {
89 				line[--len] = '\0';
90 				continue;
91 			}
92 			/* done */
93 			break;
94 		}
95 		/* anything else */
96 		if (openpam_straddch(&line, &size, &len, ch) != 0)
97 			goto fail;
98 	}
99 	if (len == 0)
100 		goto fail;
101 	if (lenp != NULL)
102 		*lenp = len;
103 	return (line);
104 fail:
105 	FREE(line);
106 	return (NULL);
107 }
108 
109 /**
110  * DEPRECATED openpam_readlinev
111  *
112  * The =openpam_readline function reads a line from a file, and returns it
113  * in a NUL-terminated buffer allocated with =!malloc.
114  *
115  * The =openpam_readline function performs a certain amount of processing
116  * on the data it reads:
117  *
118  *  - Comments (introduced by a hash sign) are stripped.
119  *
120  *  - Blank lines are ignored.
121  *
122  *  - If a line ends in a backslash, the backslash is stripped and the
123  *    next line is appended.
124  *
125  * If =lineno is not =NULL, the integer variable it points to is
126  * incremented every time a newline character is read.
127  *
128  * If =lenp is not =NULL, the length of the line (not including the
129  * terminating NUL character) is stored in the variable it points to.
130  *
131  * The caller is responsible for releasing the returned buffer by passing
132  * it to =!free.
133  *
134  * >openpam_readlinev
135  * >openpam_readword
136  */
137