gen/get_compat.c

   1 /*
   2  * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 #include <stdbool.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <fcntl.h>
  28 #include <sys/types.h>
  29 #include <sys/mman.h>
  30 #include <sys/stat.h>
  31 #include <string.h>
  32 #include <pthread.h>
  33
  34 /* Catastrophic errors only, including "out of memory" */
  35 static bool parse_error = false;
  36 static bool bootstrapping = false;
  37 static bool parsed = false;
  38 #define UNIX2003_DEFAULT_MODE true
  39 static bool unix2003_mode = UNIX2003_DEFAULT_MODE;
  40
  41 static pthread_once_t threadsafe = PTHREAD_ONCE_INIT;
  42
  43 /* There was once a lot of parsing and the ability to set diffrent commands
  44   to diffrent modes.  That is gone, but some of the scaffolding remains */
  45
  46 static void check_env_var(void) {
  47         char *mode = getenv("COMMAND_MODE");
  48
  49         if (mode) {
  50                 if (!strcasecmp(mode, "legacy")) {
  51                         unix2003_mode = false;
  52                 } else {
  53                         if (!strcasecmp(mode, "unix2003")) {
  54                                 unix2003_mode = true;
  55                         } else {
  56                                 parse_error = true;
  57                                 unix2003_mode = UNIX2003_DEFAULT_MODE;
  58                         }
  59                 }
  60         }
  61 }
  62
  63 /* Function is expected to be something like libc/malloc for a libc call,
  64 or bin/date for command line utilities.  Modes are currently:
  65   Legacy - pre-tiger behaviour, presumably UNIX2003 incompatable
  66   UNIX2003 - Unix 2003 spec compliant
  67   Bootstrap - only seen by (parts of) libc.  The compat_mode system is
  68     still starting up.  This will be seen while compat_mode parses it's
  69         config file, or reads the cache file, and only by libc functions it calls.
  70   Error - the conf file could not be parsed, either due to a severe
  71     syntax error, an I/O error, or an out of memory condition
  72
  73   mode names are case insensitatave.  You can use | ^ & and even !
  74   but no () yet, and that stuff hasn't been tested much yet, nor
  75   has it been optimised.
  76 */
  77
  78 bool
  79 compat_mode(const char *function, const char *mode) {
  80         if (!parsed && !bootstrapping) {
  81                 pthread_once(&threadsafe, check_env_var);
  82                 parsed = true;
  83         }
  84
  85         bool want2003 = !strcasecmp("unix2003", mode);
  86
  87         if (want2003) {
  88                 return unix2003_mode;
  89         }
  90
  91         bool want_legacy = !strcasecmp("legacy", mode);
  92
  93         if (want_legacy) {
  94                 return !unix2003_mode;
  95         }
  96
  97         bool want_bootstrap = !strcasecmp("bootstrap", mode);
  98
  99         if (want_bootstrap) {
 100                 return bootstrapping;
 101         }
 102
 103         bool want_error = !strcasecmp("error", mode);
 104
 105         if (want_error) {
 106                 return parse_error;
 107         }
 108
 109         char *op = NULL;
 110
 111         if (op = strpbrk(mode, "!^&|")) {
 112                 if (*op == '!') {
 113                         if (op != mode) goto syn_error;
 114                         return !compat_mode(function, mode +1);
 115                 }
 116
 117                 /* XXX char tmp[] would be better for left_arg, but
 118                   we are not sure what the max size should be...  is
 119                   alloca(3) frowned on? */
 120                 int left_sz = 1 + (op - mode);
 121                 char *left_arg = malloc(left_sz);
 122                 strlcpy(left_arg, mode, left_sz);
 123                 bool left = compat_mode(function, left_arg);
 124                 free(left_arg);
 125                 bool right = compat_mode(function, op +1);
 126
 127                 /* XXX check leftOPright syntax errors */
 128
 129                 switch(*op) {
 130                         case '^':
 131                                 return left ^ right;
 132                         case '&':
 133                                 return left && right;
 134                         case '|':
 135                                 return left || right;
 136                         default:
 137                                 goto syn_error;
 138                 }
 139         }
 140
 141 syn_error:
 142         fprintf(stderr, "invalid mode %s (while checking for %s)\n",
 143           mode, function);
 144
 145         return false;
 146 }
 147
 148 #ifdef SELF_TEST_COMPAT_MODE
 149
 150 #include <assert.h>
 151
 152 #define NEXPECTED 3
 153
 154 typedef struct {
 155         char *mode;
 156         /* [0] is unix2003 mode, [1] is legacy, [2] is Invalid_Mode */
 157         bool expected[NEXPECTED];
 158 } testcase;
 159
 160 testcase cases[] = {
 161         { "unix2003", {true, false, true}},
 162         { "legacy", {false, true, false}},
 163         { "bootstrap", {false, false, false}},
 164         { "unix2003|legacy", {true, true, true}},
 165         { "unix2003&legacy", {false, false, false}},
 166         { "unix2003|legacy|bootstrap", {true, true, true}},
 167         { "unix2003&legacy&bootstrap", {false, false, false}},
 168         { "!unix2003", {false, true, false}},
 169         { "!legacy", {true, false, true}},
 170         /* XXX ! with compound statments */
 171         { "unix2003^bootstrap", {true, false, true}},
 172         { "unix2003^legacy", {true, true, true}},
 173         { "&unix2003", {false, false, false}},
 174         { "unix2003&", {false, false, false}},
 175         { "unix2003!legacy", {false, false, false}},
 176         { "unix2003&error", {false, false, true}},
 177         { "error", {false, false, true}},
 178         { "error|unix2003", {true, false, true}},
 179         { "error|legacy", {false, true, true}},
 180         { "error&legacy", {false, false, false}},
 181 };
 182
 183 int ncases = sizeof(cases)/sizeof(testcase);
 184
 185 int
 186 main(int argc, char *argv[]) {
 187         int i, j;
 188         int failures = 0;
 189         char *settings[] = { "unix2003", "legacy", "Invalid Mode"};
 190
 191         assert(sizeof(settings) / sizeof(char *) == NEXPECTED);
 192
 193         for(i = 0; i < NEXPECTED; ++i) {
 194                 setenv("COMMAND_MODE", settings[i], 1);
 195                 char *compat_env = getenv("COMMAND_MODE");
 196                 printf("$COMMAND_MODE = %s\n", compat_env);
 197                 if (i != 0) {
 198                         /* here we force COMMAND_MODE to be checked again, which
 199                           is normally impossiable because check_env_var() is a static
 200                           function, but really nothing except the test cases wants to
 201                           try it anyway... */
 202                         check_env_var();
 203                 }
 204                 for(j = 0; j < ncases; ++j) {
 205                         bool ret = compat_mode("bin/compat_mode", cases[j].mode);
 206                         bool expect = cases[j].expected[i];
 207
 208                         if (expect != ret) {
 209                                 failures++;
 210                         }
 211
 212                         printf("Case %s got %d expected %d%s\n",
 213                           cases[j].mode, ret, expect, (ret == expect) ? "" : " FAILED");
 214                 }
 215         }
 216
 217         /* We have ncases entries in cases[], but each is run multiple
 218           times (once per entry in the settings array) thus the multiply */
 219         printf("Passed %d of %d cases\n",
 220           NEXPECTED*ncases - failures, NEXPECTED*ncases);
 221
 222         return failures ? 1 : 0;
 223 }
 224
 225 #endif