1 /* $NetBSD: openpam_straddch.c,v 1.3 2017/05/06 19:50:09 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 * $OpenPAM: openpam_straddch.c 938 2017-04-30 21:34:42Z des $ 32 */ 33 34 #ifdef HAVE_CONFIG_H 35 # include "config.h" 36 #endif 37 38 #include <sys/cdefs.h> 39 __RCSID("$NetBSD: openpam_straddch.c,v 1.3 2017/05/06 19:50:09 christos Exp $"); 40 41 #include <errno.h> 42 #include <stdlib.h> 43 44 #include <security/pam_appl.h> 45 46 #include "openpam_impl.h" 47 48 #define MIN_STR_SIZE 32 49 50 /* 51 * OpenPAM extension 52 * 53 * Add a character to a string, expanding the buffer if needed. 54 */ 55 56 int 57 openpam_straddch(char **str, size_t *size, size_t *len, int ch) 58 { 59 size_t tmpsize; 60 char *tmpstr; 61 62 if (*str == NULL) { 63 /* initial allocation */ 64 tmpsize = MIN_STR_SIZE; 65 if ((tmpstr = malloc(tmpsize)) == NULL) { 66 openpam_log(PAM_LOG_ERROR, "malloc(): %m"); 67 errno = ENOMEM; 68 return (-1); 69 } 70 *str = tmpstr; 71 *size = tmpsize; 72 *len = 0; 73 } else if (ch != 0 && *len + 1 >= *size) { 74 /* additional space required */ 75 tmpsize = *size * 2; 76 if ((tmpstr = realloc(*str, tmpsize)) == NULL) { 77 openpam_log(PAM_LOG_ERROR, "realloc(): %m"); 78 errno = ENOMEM; 79 return (-1); 80 } 81 *size = tmpsize; 82 *str = tmpstr; 83 } 84 if (ch != 0) { 85 (*str)[*len] = (char)ch; 86 ++*len; 87 } 88 (*str)[*len] = '\0'; 89 return (0); 90 } 91 92 /** 93 * The =openpam_straddch function appends a character to a dynamically 94 * allocated NUL-terminated buffer, reallocating the buffer as needed. 95 * 96 * The =str argument points to a variable containing either a pointer to 97 * an existing buffer or =NULL. 98 * If the value of the variable pointed to by =str is =NULL, a new buffer 99 * is allocated. 100 * 101 * The =size and =len argument point to variables used to hold the size 102 * of the buffer and the length of the string it contains, respectively. 103 * 104 * The final argument, =ch, is the character that should be appended to 105 * the string. If =ch is 0, nothing is appended, but a new buffer is 106 * still allocated if =str is NULL. This can be used to "bootstrap" the 107 * string. 108 * 109 * If a new buffer is allocated or an existing buffer is reallocated to 110 * make room for the additional character, =str and =size are updated 111 * accordingly. 112 * 113 * The =openpam_straddch function ensures that the buffer is always 114 * NUL-terminated. 115 * 116 * If the =openpam_straddch function is successful, it increments the 117 * integer variable pointed to by =len (unless =ch was 0) and returns 0. 118 * Otherwise, it leaves the variables pointed to by =str, =size and =len 119 * unmodified, sets :errno to =ENOMEM and returns -1. 120 * 121 * AUTHOR DES 122 */ 123