1 /* $NetBSD: openpam_straddch.c,v 1.4 2023/06/30 21:46:20 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2012 Dag-Erling Smørgrav
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote
16 * products derived from this software without specific prior written
17 * permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #ifdef HAVE_CONFIG_H
33 # include "config.h"
34 #endif
35
36 #include <sys/cdefs.h>
37 __RCSID("$NetBSD: openpam_straddch.c,v 1.4 2023/06/30 21:46:20 christos Exp $");
38
39 #include <errno.h>
40 #include <stdlib.h>
41
42 #include <security/pam_appl.h>
43
44 #include "openpam_impl.h"
45
46 #define MIN_STR_SIZE 32
47
48 /*
49 * OpenPAM extension
50 *
51 * Add a character to a string, expanding the buffer if needed.
52 */
53
54 int
openpam_straddch(char ** str,size_t * size,size_t * len,int ch)55 openpam_straddch(char **str, size_t *size, size_t *len, int ch)
56 {
57 size_t tmpsize;
58 char *tmpstr;
59
60 if (*str == NULL) {
61 /* initial allocation */
62 tmpsize = MIN_STR_SIZE;
63 if ((tmpstr = malloc(tmpsize)) == NULL) {
64 errno = ENOMEM;
65 return (-1);
66 }
67 *str = tmpstr;
68 *size = tmpsize;
69 *len = 0;
70 } else if (ch != 0 && *len + 1 >= *size) {
71 /* additional space required */
72 tmpsize = *size * 2;
73 if ((tmpstr = realloc(*str, tmpsize)) == NULL) {
74 errno = ENOMEM;
75 return (-1);
76 }
77 *size = tmpsize;
78 *str = tmpstr;
79 }
80 if (ch != 0) {
81 (*str)[*len] = (char)ch;
82 ++*len;
83 }
84 (*str)[*len] = '\0';
85 return (0);
86 }
87
88 /**
89 * The =openpam_straddch function appends a character to a dynamically
90 * allocated NUL-terminated buffer, reallocating the buffer as needed.
91 *
92 * The =str argument points to a variable containing either a pointer to
93 * an existing buffer or =NULL.
94 * If the value of the variable pointed to by =str is =NULL, a new buffer
95 * is allocated.
96 *
97 * The =size and =len argument point to variables used to hold the size
98 * of the buffer and the length of the string it contains, respectively.
99 *
100 * The final argument, =ch, is the character that should be appended to
101 * the string. If =ch is 0, nothing is appended, but a new buffer is
102 * still allocated if =str is NULL. This can be used to "bootstrap" the
103 * string.
104 *
105 * If a new buffer is allocated or an existing buffer is reallocated to
106 * make room for the additional character, =str and =size are updated
107 * accordingly.
108 *
109 * The =openpam_straddch function ensures that the buffer is always
110 * NUL-terminated.
111 *
112 * If the =openpam_straddch function is successful, it increments the
113 * integer variable pointed to by =len (unless =ch was 0) and returns 0.
114 * Otherwise, it leaves the variables pointed to by =str, =size and =len
115 * unmodified, sets :errno to =ENOMEM and returns -1.
116 *
117 * AUTHOR DES
118 */
119