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] [-bgu 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 " -b name\t\t\tblank the 'name=$name' entry, corrupting it\n" 72 " -c 1|2|3|4\t\t\tClear environ variable using method:\n" 73 "\t\t\t\t1 - set environ to NULL pointer\n" 74 "\t\t\t\t2 - set environ[0] to NULL pointer\n" 75 "\t\t\t\t3 - set environ to calloc()'d NULL-terminated array\n" 76 "\t\t\t\t4 - set environ to static NULL-terminated array\n" 77 " -g name\t\t\tgetenv(name)\n" 78 " -h\t\t\t\tHelp\n" 79 " -p name=value\t\t\tputenv(name=value)\n" 80 " -r\t\t\t\treplace environ with { \"FOO=bar\", NULL }\n" 81 " -s name value overwrite\tsetenv(name, value, overwrite)\n" 82 " -t\t\t\t\tOutput is suitable for testing (no newlines)\n" 83 " -u name\t\t\tunsetenv(name)\n", 84 basename(program)); 85 86 return; 87 } 88 89 90 /* 91 * Print the return value of a call along with errno upon error else zero. 92 * Also, use the eol string based upon whether running in test mode or not. 93 */ 94 static void 95 print_rtrn_errno(int rtrnVal, const char *eol) 96 { 97 printf("%d %d%s", rtrnVal, rtrnVal != 0 ? errno : 0, eol); 98 99 return; 100 } 101 102 static void 103 blank_env(const char *var) 104 { 105 char **newenviron; 106 int n, varlen; 107 108 if (environ == NULL) 109 return; 110 111 for (n = 0; environ[n] != NULL; n++) 112 ; 113 newenviron = malloc(sizeof(char *) * (n + 1)); 114 varlen = strlen(var); 115 for (; n >= 0; n--) { 116 newenviron[n] = environ[n]; 117 if (newenviron[n] != NULL && 118 strncmp(newenviron[n], var, varlen) == 0 && 119 newenviron[n][varlen] == '=') 120 newenviron[n] += strlen(newenviron[n]); 121 } 122 environ = newenviron; 123 } 124 125 int 126 main(int argc, char **argv) 127 { 128 char arg; 129 const char *eol = "\n"; 130 const char *value; 131 static char *emptyEnv[] = { NULL }; 132 static char *staticEnv[] = { "FOO=bar", NULL }; 133 134 if (argc == 1) { 135 usage(argv[0]); 136 exit(EXIT_FAILURE); 137 } 138 139 /* The entire program is basically executed from this loop. */ 140 while ((arg = getopt(argc, argv, "DGS:Ub:c:g:hp:rs:tu:")) != -1) { 141 switch (arg) { 142 case 'b': 143 blank_env(optarg); 144 break; 145 146 case 'c': 147 switch (atoi(optarg)) { 148 case 1: 149 environ = NULL; 150 break; 151 152 case 2: 153 environ[0] = NULL; 154 break; 155 156 case 3: 157 environ = calloc(1, sizeof(*environ)); 158 break; 159 160 case 4: 161 environ = emptyEnv; 162 break; 163 } 164 break; 165 166 case 'D': 167 dump_environ(); 168 break; 169 170 case 'G': 171 case 'g': 172 value = getenv(arg == 'g' ? optarg : NULL); 173 printf("%s%s", value == NULL ? "*NULL*" : value, eol); 174 break; 175 176 case 'p': 177 print_rtrn_errno(putenv(optarg), eol); 178 break; 179 180 case 'r': 181 environ = staticEnv; 182 break; 183 184 case 'S': 185 print_rtrn_errno(setenv(NULL, optarg, 186 atoi(argv[optind])), eol); 187 optind += 1; 188 break; 189 190 case 's': 191 print_rtrn_errno(setenv(optarg, argv[optind], 192 atoi(argv[optind + 1])), eol); 193 optind += 2; 194 break; 195 196 case 't': 197 eol = " "; 198 break; 199 200 case 'U': 201 case 'u': 202 print_rtrn_errno(unsetenv(arg == 'u' ? optarg : NULL), 203 eol); 204 break; 205 206 case 'h': 207 default: 208 usage(argv[0]); 209 exit(EXIT_FAILURE); 210 } 211 } 212 213 /* Output a closing newline in test mode. */ 214 if (eol[0] == ' ') 215 printf("\n"); 216 217 return (EXIT_SUCCESS); 218 } 219