1 /*- 2 * Copyright (c) 2007-2008 Sean C. Farley <scf@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer, 10 * without modification, immediately at the beginning of the file. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 #include <errno.h> 27 #include <libgen.h> 28 #include <stdbool.h> 29 #include <stdio.h> 30 #include <stdlib.h> 31 #include <string.h> 32 #include <unistd.h> 33 34 35 #include <sys/cdefs.h> 36 __FBSDID("$FreeBSD$"); 37 38 39 extern char **environ; 40 41 42 /* 43 * Print entire environ array. 44 */ 45 static void 46 dump_environ(void) 47 { 48 char **environPtr; 49 50 for (environPtr = environ; *environPtr != NULL; environPtr++) 51 printf("%s\n", *environPtr); 52 53 return; 54 } 55 56 57 /* 58 * Print usage. 59 */ 60 static void 61 usage(const char *program) 62 { 63 fprintf(stderr, "Usage: %s [-DGUchrt] [-c 1|2|3|4] [-gu name] " 64 "[-p name=value]\n" 65 "\t[(-S|-s name) value overwrite]\n\n" 66 "Options:\n" 67 " -D\t\t\t\tDump environ\n" 68 " -G name\t\t\tgetenv(NULL)\n" 69 " -S value overwrite\t\tsetenv(NULL, value, overwrite)\n" 70 " -U\t\t\t\tunsetenv(NULL)\n" 71 " -c 1|2|3|4\t\t\tClear environ variable using method:\n" 72 "\t\t\t\t1 - set environ to NULL pointer\n" 73 "\t\t\t\t2 - set environ[0] to NULL pointer\n" 74 "\t\t\t\t3 - set environ to calloc()'d NULL-terminated array\n" 75 "\t\t\t\t4 - set environ to static NULL-terminated array\n" 76 " -g name\t\t\tgetenv(name)\n" 77 " -h\t\t\t\tHelp\n" 78 " -p name=value\t\t\tputenv(name=value)\n" 79 " -r\t\t\t\treplace environ with { \"FOO=bar\", NULL }\n" 80 " -s name value overwrite\tsetenv(name, value, overwrite)\n" 81 " -t\t\t\t\tOutput is suitable for testing (no newlines)\n" 82 " -u name\t\t\tunsetenv(name)\n", 83 basename(program)); 84 85 return; 86 } 87 88 89 /* 90 * Print the return value of a call along with errno upon error else zero. 91 * Also, use the eol string based upon whether running in test mode or not. 92 */ 93 static void 94 print_rtrn_errno(int rtrnVal, const char *eol) 95 { 96 printf("%d %d%s", rtrnVal, rtrnVal != 0 ? errno : 0, eol); 97 98 return; 99 } 100 101 102 int 103 main(int argc, char **argv) 104 { 105 char arg; 106 const char *eol = "\n"; 107 const char *value; 108 static char *emptyEnv[] = { NULL }; 109 static char *staticEnv[] = { "FOO=bar", NULL }; 110 111 if (argc == 1) { 112 usage(argv[0]); 113 exit(EXIT_FAILURE); 114 } 115 116 /* The entire program is basically executed from this loop. */ 117 while ((arg = getopt(argc, argv, "DGS:Uc:g:hp:rs:tu:")) != -1) { 118 switch (arg) { 119 case 'c': 120 switch (atoi(optarg)) { 121 case 1: 122 environ = NULL; 123 break; 124 125 case 2: 126 environ[0] = NULL; 127 break; 128 129 case 3: 130 environ = calloc(1, sizeof(*environ)); 131 break; 132 133 case 4: 134 environ = emptyEnv; 135 break; 136 } 137 break; 138 139 case 'D': 140 dump_environ(); 141 break; 142 143 case 'G': 144 case 'g': 145 value = getenv(arg == 'g' ? optarg : NULL); 146 printf("%s%s", value == NULL ? "*NULL*" : value, eol); 147 break; 148 149 case 'p': 150 print_rtrn_errno(putenv(optarg), eol); 151 break; 152 153 case 'r': 154 environ = staticEnv; 155 break; 156 157 case 'S': 158 print_rtrn_errno(setenv(NULL, optarg, 159 atoi(argv[optind])), eol); 160 optind += 1; 161 break; 162 163 case 's': 164 print_rtrn_errno(setenv(optarg, argv[optind], 165 atoi(argv[optind + 1])), eol); 166 optind += 2; 167 break; 168 169 case 't': 170 eol = " "; 171 break; 172 173 case 'U': 174 case 'u': 175 print_rtrn_errno(unsetenv(arg == 'u' ? optarg : NULL), 176 eol); 177 break; 178 179 case 'h': 180 default: 181 usage(argv[0]); 182 exit(EXIT_FAILURE); 183 } 184 } 185 186 /* Output a closing newline in test mode. */ 187 if (eol[0] == ' ') 188 printf("\n"); 189 190 return (EXIT_SUCCESS); 191 } 192