openpam_readline.c revision 228690
1/*- 2 * Copyright (c) 2003 Networks Associates Technology, Inc. 3 * Copyright (c) 2004-2011 Dag-Erling Sm��rgrav 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: openpam_readline.c 473 2011-11-03 10:48:25Z des $ 36 */ 37 38#ifdef HAVE_CONFIG_H 39# include "config.h" 40#endif 41 42#include <ctype.h> 43#include <stdio.h> 44#include <stdlib.h> 45 46#include <security/pam_appl.h> 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 57char * 58openpam_readline(FILE *f, int *lineno, size_t *lenp) 59{ 60 char *line; 61 size_t len, size; 62 int ch; 63 64 if ((line = malloc(MIN_LINE_LENGTH)) == NULL) 65 return (NULL); 66 size = MIN_LINE_LENGTH; 67 len = 0; 68 69#define line_putch(ch) do { \ 70 if (len >= size - 1) { \ 71 char *tmp = realloc(line, size *= 2); \ 72 if (tmp == NULL) \ 73 goto fail; \ 74 line = tmp; \ 75 } \ 76 line[len++] = ch; \ 77 line[len] = '\0'; \ 78} while (0) 79 80 for (;;) { 81 ch = fgetc(f); 82 /* strip comment */ 83 if (ch == '#') { 84 do { 85 ch = fgetc(f); 86 } while (ch != EOF && ch != '\n'); 87 } 88 /* eof */ 89 if (ch == EOF) { 90 /* done */ 91 break; 92 } 93 /* eol */ 94 if (ch == '\n') { 95 if (lineno != NULL) 96 ++*lineno; 97 /* skip blank lines */ 98 if (len == 0) 99 continue; 100 /* continuation */ 101 if (line[len - 1] == '\\') { 102 line[--len] = '\0'; 103 continue; 104 } 105 /* done */ 106 break; 107 } 108 /* whitespace */ 109 if (isspace(ch)) { 110 /* ignore leading whitespace */ 111 /* collapse linear whitespace */ 112 if (len > 0 && line[len - 1] != ' ') 113 line_putch(' '); 114 continue; 115 } 116 /* anything else */ 117 line_putch(ch); 118 } 119 120 /* remove trailing whitespace */ 121 while (len > 0 && isspace((unsigned char)line[len - 1])) 122 --len; 123 line[len] = '\0'; 124 if (len == 0) 125 goto fail; 126 if (lenp != NULL) 127 *lenp = len; 128 return (line); 129fail: 130 FREE(line); 131 return (NULL); 132} 133 134/** 135 * The =openpam_readline function reads a line from a file, and returns it 136 * in a NUL-terminated buffer allocated with =malloc. 137 * 138 * The =openpam_readline function performs a certain amount of processing 139 * on the data it reads: 140 * 141 * - Comments (introduced by a hash sign) are stripped, as is leading and 142 * trailing whitespace. 143 * - Any amount of linear whitespace is collapsed to a single space. 144 * - Blank lines are ignored. 145 * - If a line ends in a backslash, the backslash is stripped and the 146 * next line is appended. 147 * 148 * If =lineno is not =NULL, the integer variable it points to is 149 * incremented every time a newline character is read. 150 * 151 * If =lenp is not =NULL, the length of the line (not including the 152 * terminating NUL character) is stored in the variable it points to. 153 * 154 * The caller is responsible for releasing the returned buffer by passing 155 * it to =free. 156 */ 157