1 | /* $NetBSD: setmode.c,v 1.30 2003/08/07 16:42:56 agc Exp $ */
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2 |
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3 | /*
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4 | * Copyright (c) 1989, 1993, 1994
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5 | * The Regents of the University of California. All rights reserved.
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6 | *
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7 | * This code is derived from software contributed to Berkeley by
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8 | * Dave Borman at Cray Research, Inc.
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9 | *
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10 | * Redistribution and use in source and binary forms, with or without
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11 | * modification, are permitted provided that the following conditions
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12 | * are met:
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13 | * 1. Redistributions of source code must retain the above copyright
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14 | * notice, this list of conditions and the following disclaimer.
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15 | * 2. Redistributions in binary form must reproduce the above copyright
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16 | * notice, this list of conditions and the following disclaimer in the
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17 | * documentation and/or other materials provided with the distribution.
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18 | * 3. Neither the name of the University nor the names of its contributors
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19 | * may be used to endorse or promote products derived from this software
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20 | * without specific prior written permission.
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21 | *
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22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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32 | * SUCH DAMAGE.
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33 | */
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34 |
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35 | /*#include <sys/cdefs.h>*/
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36 | #if defined(LIBC_SCCS) && !defined(lint)
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37 | #if 0
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38 | static char sccsid[] = "@(#)setmode.c 8.2 (Berkeley) 3/25/94";
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39 | #else
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40 | __RCSID("$NetBSD: setmode.c,v 1.30 2003/08/07 16:42:56 agc Exp $");
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41 | #endif
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42 | #endif /* LIBC_SCCS and not lint */
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43 |
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44 | /*#include "namespace.h"*/
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45 | #include "config.h"
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46 | #include <sys/types.h>
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47 | #include <sys/stat.h>
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48 |
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49 | #include <assert.h>
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50 | #include <ctype.h>
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51 | #include <errno.h>
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52 | #include <signal.h>
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53 | #include <stdlib.h>
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54 | #ifndef _MSC_VER
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55 | #include <unistd.h>
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56 | #else
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57 | #include "mscfakes.h"
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58 | #endif
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59 |
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60 | #ifdef SETMODE_DEBUG
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61 | #include <stdio.h>
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62 | #endif
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63 |
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64 | /*#ifdef __weak_alias
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65 | __weak_alias(getmode,_getmode)
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66 | __weak_alias(setmode,_setmode)
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67 | #endif*/
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68 |
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69 | #define SET_LEN 6 /* initial # of bitcmd struct to malloc */
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70 | #define SET_LEN_INCR 4 /* # of bitcmd structs to add as needed */
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71 |
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72 | typedef struct bitcmd {
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73 | char cmd;
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74 | char cmd2;
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75 | mode_t bits;
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76 | } BITCMD;
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77 |
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78 | #define CMD2_CLR 0x01
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79 | #define CMD2_SET 0x02
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80 | #define CMD2_GBITS 0x04
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81 | #define CMD2_OBITS 0x08
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82 | #define CMD2_UBITS 0x10
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83 |
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84 | static BITCMD *addcmd(BITCMD *, int, int, int, u_int);
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85 | static void compress_mode(BITCMD *);
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86 | #ifdef SETMODE_DEBUG
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87 | static void dumpmode(BITCMD *);
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88 | #endif
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89 |
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90 | #ifndef _DIAGASSERT
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91 | # define _DIAGASSERT assert
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92 | #endif
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93 |
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94 | #ifndef S_ISTXT
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95 | # ifdef S_ISVTX
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96 | # define S_ISTXT S_ISVTX
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97 | # else
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98 | # define S_ISTXT 0
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99 | # endif
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100 | #endif /* !S_ISTXT */
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101 |
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102 | extern mode_t g_fUMask; /* Initialize in main() and keep up to date. */
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103 |
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104 |
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105 | /*
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106 | * Given the old mode and an array of bitcmd structures, apply the operations
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107 | * described in the bitcmd structures to the old mode, and return the new mode.
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108 | * Note that there is no '=' command; a strict assignment is just a '-' (clear
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109 | * bits) followed by a '+' (set bits).
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110 | */
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111 | mode_t
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112 | bsd_getmode(bbox, omode)
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113 | const void *bbox;
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114 | mode_t omode;
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115 | {
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116 | const BITCMD *set;
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117 | mode_t clrval, newmode, value;
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118 |
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119 | _DIAGASSERT(bbox != NULL);
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120 |
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121 | set = (const BITCMD *)bbox;
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122 | newmode = omode;
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123 | for (value = 0;; set++)
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124 | switch(set->cmd) {
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125 | /*
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126 | * When copying the user, group or other bits around, we "know"
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127 | * where the bits are in the mode so that we can do shifts to
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128 | * copy them around. If we don't use shifts, it gets real
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129 | * grundgy with lots of single bit checks and bit sets.
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130 | */
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131 | case 'u':
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132 | value = (newmode & S_IRWXU) >> 6;
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133 | goto common;
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134 |
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135 | case 'g':
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136 | value = (newmode & S_IRWXG) >> 3;
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137 | goto common;
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138 |
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139 | case 'o':
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140 | value = newmode & S_IRWXO;
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141 | common: if (set->cmd2 & CMD2_CLR) {
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142 | clrval =
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143 | (set->cmd2 & CMD2_SET) ? S_IRWXO : value;
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144 | if (set->cmd2 & CMD2_UBITS)
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145 | newmode &= ~((clrval<<6) & set->bits);
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146 | if (set->cmd2 & CMD2_GBITS)
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147 | newmode &= ~((clrval<<3) & set->bits);
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148 | if (set->cmd2 & CMD2_OBITS)
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149 | newmode &= ~(clrval & set->bits);
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150 | }
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151 | if (set->cmd2 & CMD2_SET) {
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152 | if (set->cmd2 & CMD2_UBITS)
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153 | newmode |= (value<<6) & set->bits;
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154 | if (set->cmd2 & CMD2_GBITS)
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155 | newmode |= (value<<3) & set->bits;
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156 | if (set->cmd2 & CMD2_OBITS)
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157 | newmode |= value & set->bits;
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158 | }
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159 | break;
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160 |
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161 | case '+':
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162 | newmode |= set->bits;
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163 | break;
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164 |
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165 | case '-':
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166 | newmode &= ~set->bits;
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167 | break;
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168 |
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169 | case 'X':
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170 | if (omode & (S_IFDIR|S_IXUSR|S_IXGRP|S_IXOTH))
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171 | newmode |= set->bits;
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172 | break;
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173 |
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174 | case '\0':
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175 | default:
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176 | #ifdef SETMODE_DEBUG
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177 | (void)printf("getmode:%04o -> %04o\n", omode, newmode);
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178 | #endif
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179 | return (newmode);
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180 | }
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181 | }
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182 |
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183 | #define ADDCMD(a, b, c, d) do { \
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184 | if (set >= endset) { \
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185 | BITCMD *newset; \
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186 | setlen += SET_LEN_INCR; \
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187 | newset = realloc(saveset, sizeof(BITCMD) * setlen); \
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188 | if (newset == NULL) { \
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189 | free(saveset); \
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190 | return (NULL); \
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191 | } \
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192 | set = newset + (set - saveset); \
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193 | saveset = newset; \
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194 | endset = newset + (setlen - 2); \
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195 | } \
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196 | set = addcmd(set, (a), (b), (c), (d)); \
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197 | } while (/*CONSTCOND*/0)
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198 |
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199 | #define STANDARD_BITS (S_ISUID|S_ISGID|S_IRWXU|S_IRWXG|S_IRWXO)
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200 |
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201 | void *
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202 | bsd_setmode(p)
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203 | const char *p;
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204 | {
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205 | int perm, who;
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206 | char op, *ep;
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207 | BITCMD *set, *saveset, *endset;
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208 | #ifndef _MSC_VER
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209 | sigset_t signset, sigoset;
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210 | #endif
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211 | mode_t mask;
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212 | int equalopdone = 0; /* pacify gcc */
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213 | int permXbits, setlen;
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214 |
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215 | if (!*p)
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216 | return (NULL);
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217 |
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218 | /*
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219 | * Get a copy of the mask for the permissions that are mask relative.
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220 | * Flip the bits, we want what's not set. Since it's possible that
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221 | * the caller is opening files inside a signal handler, protect them
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222 | * as best we can.
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223 | */
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224 | #ifndef _MSC_VER
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225 | sigfillset(&signset);
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226 | (void)sigprocmask(SIG_BLOCK, &signset, &sigoset);
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227 | #endif
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228 | mask = g_fUMask;
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229 | assert(mask == umask(g_fUMask));
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230 | mask = ~mask;
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231 | #ifndef _MSC_VER
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232 | (void)sigprocmask(SIG_SETMASK, &sigoset, NULL);
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233 | #endif
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234 |
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235 | setlen = SET_LEN + 2;
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236 |
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237 | if ((set = malloc((u_int)(sizeof(BITCMD) * setlen))) == NULL)
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238 | return (NULL);
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239 | saveset = set;
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240 | endset = set + (setlen - 2);
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241 |
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242 | /*
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243 | * If an absolute number, get it and return; disallow non-octal digits
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244 | * or illegal bits.
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245 | */
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246 | if (isdigit((unsigned char)*p)) {
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247 | perm = (mode_t)strtol(p, &ep, 8);
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248 | if (*ep || perm & ~(STANDARD_BITS|S_ISTXT)) {
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249 | free(saveset);
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250 | return (NULL);
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251 | }
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252 | ADDCMD('=', (STANDARD_BITS|S_ISTXT), perm, mask);
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253 | set->cmd = 0;
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254 | return (saveset);
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255 | }
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256 |
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257 | /*
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258 | * Build list of structures to set/clear/copy bits as described by
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259 | * each clause of the symbolic mode.
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260 | */
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261 | for (;;) {
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262 | /* First, find out which bits might be modified. */
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263 | for (who = 0;; ++p) {
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264 | switch (*p) {
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265 | case 'a':
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266 | who |= STANDARD_BITS;
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267 | break;
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268 | case 'u':
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269 | who |= S_ISUID|S_IRWXU;
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270 | break;
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271 | case 'g':
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272 | who |= S_ISGID|S_IRWXG;
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273 | break;
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274 | case 'o':
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275 | who |= S_IRWXO;
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276 | break;
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277 | default:
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278 | goto getop;
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279 | }
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280 | }
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281 |
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282 | getop: if ((op = *p++) != '+' && op != '-' && op != '=') {
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283 | free(saveset);
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284 | return (NULL);
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285 | }
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286 | if (op == '=')
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287 | equalopdone = 0;
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288 |
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289 | who &= ~S_ISTXT;
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290 | for (perm = 0, permXbits = 0;; ++p) {
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291 | switch (*p) {
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292 | case 'r':
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293 | perm |= S_IRUSR|S_IRGRP|S_IROTH;
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294 | break;
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295 | case 's':
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296 | /*
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297 | * If specific bits where requested and
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298 | * only "other" bits ignore set-id.
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299 | */
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300 | if (who == 0 || (who & ~S_IRWXO))
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301 | perm |= S_ISUID|S_ISGID;
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302 | break;
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303 | case 't':
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304 | /*
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305 | * If specific bits where requested and
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306 | * only "other" bits ignore set-id.
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307 | */
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308 | if (who == 0 || (who & ~S_IRWXO)) {
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309 | who |= S_ISTXT;
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310 | perm |= S_ISTXT;
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311 | }
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312 | break;
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313 | case 'w':
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314 | perm |= S_IWUSR|S_IWGRP|S_IWOTH;
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315 | break;
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316 | case 'X':
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317 | permXbits = S_IXUSR|S_IXGRP|S_IXOTH;
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318 | break;
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319 | case 'x':
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320 | perm |= S_IXUSR|S_IXGRP|S_IXOTH;
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321 | break;
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322 | case 'u':
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323 | case 'g':
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324 | case 'o':
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325 | /*
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326 | * When ever we hit 'u', 'g', or 'o', we have
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327 | * to flush out any partial mode that we have,
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328 | * and then do the copying of the mode bits.
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329 | */
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330 | if (perm) {
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331 | ADDCMD(op, who, perm, mask);
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332 | perm = 0;
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333 | }
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334 | if (op == '=')
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335 | equalopdone = 1;
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336 | if (op == '+' && permXbits) {
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337 | ADDCMD('X', who, permXbits, mask);
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338 | permXbits = 0;
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339 | }
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340 | ADDCMD(*p, who, op, mask);
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341 | break;
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342 |
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343 | default:
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344 | /*
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345 | * Add any permissions that we haven't already
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346 | * done.
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347 | */
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348 | if (perm || (op == '=' && !equalopdone)) {
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349 | if (op == '=')
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350 | equalopdone = 1;
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351 | ADDCMD(op, who, perm, mask);
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352 | perm = 0;
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353 | }
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354 | if (permXbits) {
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355 | ADDCMD('X', who, permXbits, mask);
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356 | permXbits = 0;
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357 | }
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358 | goto apply;
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359 | }
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360 | }
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361 |
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362 | apply: if (!*p)
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363 | break;
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364 | if (*p != ',')
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365 | goto getop;
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366 | ++p;
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367 | }
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368 | set->cmd = 0;
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369 | #ifdef SETMODE_DEBUG
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370 | (void)printf("Before compress_mode()\n");
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371 | dumpmode(saveset);
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372 | #endif
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373 | compress_mode(saveset);
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374 | #ifdef SETMODE_DEBUG
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375 | (void)printf("After compress_mode()\n");
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376 | dumpmode(saveset);
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377 | #endif
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378 | return (saveset);
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379 | }
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380 |
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381 | static BITCMD *
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382 | addcmd(set, op, who, oparg, mask)
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383 | BITCMD *set;
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384 | int oparg, who;
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385 | int op;
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386 | u_int mask;
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387 | {
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388 |
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389 | _DIAGASSERT(set != NULL);
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390 |
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391 | switch (op) {
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392 | case '=':
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393 | set->cmd = '-';
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394 | set->bits = who ? who : STANDARD_BITS;
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395 | set++;
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396 |
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397 | op = '+';
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398 | /* FALLTHROUGH */
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399 | case '+':
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400 | case '-':
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401 | case 'X':
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402 | set->cmd = op;
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403 | set->bits = (who ? (mode_t)who : mask) & oparg;
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404 | break;
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405 |
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406 | case 'u':
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407 | case 'g':
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408 | case 'o':
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409 | set->cmd = op;
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410 | if (who) {
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411 | set->cmd2 = ((who & S_IRUSR) ? CMD2_UBITS : 0) |
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412 | ((who & S_IRGRP) ? CMD2_GBITS : 0) |
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413 | ((who & S_IROTH) ? CMD2_OBITS : 0);
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414 | set->bits = (mode_t)~0;
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415 | } else {
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416 | set->cmd2 = CMD2_UBITS | CMD2_GBITS | CMD2_OBITS;
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417 | set->bits = mask;
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418 | }
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419 |
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420 | if (oparg == '+')
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421 | set->cmd2 |= CMD2_SET;
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422 | else if (oparg == '-')
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423 | set->cmd2 |= CMD2_CLR;
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424 | else if (oparg == '=')
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425 | set->cmd2 |= CMD2_SET|CMD2_CLR;
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426 | break;
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427 | }
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428 | return (set + 1);
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429 | }
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430 |
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431 | #ifdef SETMODE_DEBUG
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432 | static void
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433 | dumpmode(set)
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434 | BITCMD *set;
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435 | {
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436 |
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437 | _DIAGASSERT(set != NULL);
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438 |
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439 | for (; set->cmd; ++set)
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440 | (void)printf("cmd: '%c' bits %04o%s%s%s%s%s%s\n",
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441 | set->cmd, set->bits, set->cmd2 ? " cmd2:" : "",
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442 | set->cmd2 & CMD2_CLR ? " CLR" : "",
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443 | set->cmd2 & CMD2_SET ? " SET" : "",
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444 | set->cmd2 & CMD2_UBITS ? " UBITS" : "",
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445 | set->cmd2 & CMD2_GBITS ? " GBITS" : "",
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446 | set->cmd2 & CMD2_OBITS ? " OBITS" : "");
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447 | }
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448 | #endif
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449 |
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450 | /*
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451 | * Given an array of bitcmd structures, compress by compacting consecutive
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452 | * '+', '-' and 'X' commands into at most 3 commands, one of each. The 'u',
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453 | * 'g' and 'o' commands continue to be separate. They could probably be
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454 | * compacted, but it's not worth the effort.
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455 | */
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456 | static void
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457 | compress_mode(set)
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458 | BITCMD *set;
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459 | {
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460 | BITCMD *nset;
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461 | int setbits, clrbits, Xbits, op;
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462 |
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463 | _DIAGASSERT(set != NULL);
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464 |
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465 | for (nset = set;;) {
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466 | /* Copy over any 'u', 'g' and 'o' commands. */
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467 | while ((op = nset->cmd) != '+' && op != '-' && op != 'X') {
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468 | *set++ = *nset++;
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469 | if (!op)
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470 | return;
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471 | }
|
---|
472 |
|
---|
473 | for (setbits = clrbits = Xbits = 0;; nset++) {
|
---|
474 | if ((op = nset->cmd) == '-') {
|
---|
475 | clrbits |= nset->bits;
|
---|
476 | setbits &= ~nset->bits;
|
---|
477 | Xbits &= ~nset->bits;
|
---|
478 | } else if (op == '+') {
|
---|
479 | setbits |= nset->bits;
|
---|
480 | clrbits &= ~nset->bits;
|
---|
481 | Xbits &= ~nset->bits;
|
---|
482 | } else if (op == 'X')
|
---|
483 | Xbits |= nset->bits & ~setbits;
|
---|
484 | else
|
---|
485 | break;
|
---|
486 | }
|
---|
487 | if (clrbits) {
|
---|
488 | set->cmd = '-';
|
---|
489 | set->cmd2 = 0;
|
---|
490 | set->bits = clrbits;
|
---|
491 | set++;
|
---|
492 | }
|
---|
493 | if (setbits) {
|
---|
494 | set->cmd = '+';
|
---|
495 | set->cmd2 = 0;
|
---|
496 | set->bits = setbits;
|
---|
497 | set++;
|
---|
498 | }
|
---|
499 | if (Xbits) {
|
---|
500 | set->cmd = 'X';
|
---|
501 | set->cmd2 = 0;
|
---|
502 | set->bits = Xbits;
|
---|
503 | set++;
|
---|
504 | }
|
---|
505 | }
|
---|
506 | }
|
---|