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 extern char **environ; 37 38 39 /* 40 * Print entire environ array. 41 */ 42 static void 43 dump_environ(void) 44 { 45 char **environPtr; 46 47 for (environPtr = environ; *environPtr != NULL; environPtr++) 48 printf("%s\n", *environPtr); 49 50 return; 51 } 52 53 54 /* 55 * Print usage. 56 */ 57 static void 58 usage(const char *program) 59 { 60 fprintf(stderr, "Usage: %s [-DGUchrt] [-c 1|2|3|4] [-bgu name] " 61 "[-p name=value]\n" 62 "\t[(-S|-s name) value overwrite]\n\n" 63 "Options:\n" 64 " -D\t\t\t\tDump environ\n" 65 " -G name\t\t\tgetenv(NULL)\n" 66 " -S value overwrite\t\tsetenv(NULL, value, overwrite)\n" 67 " -U\t\t\t\tunsetenv(NULL)\n" 68 " -b name\t\t\tblank the 'name=$name' entry, corrupting it\n" 69 " -c 1|2|3|4\t\t\tClear environ variable using method:\n" 70 "\t\t\t\t1 - set environ to NULL pointer\n" 71 "\t\t\t\t2 - set environ[0] to NULL pointer\n" 72 "\t\t\t\t3 - set environ to calloc()'d NULL-terminated array\n" 73 "\t\t\t\t4 - set environ to static NULL-terminated array\n" 74 " -g name\t\t\tgetenv(name)\n" 75 " -h\t\t\t\tHelp\n" 76 " -p name=value\t\t\tputenv(name=value)\n" 77 " -r\t\t\t\treplace environ with { \"FOO=bar\", NULL }\n" 78 " -s name value overwrite\tsetenv(name, value, overwrite)\n" 79 " -t\t\t\t\tOutput is suitable for testing (no newlines)\n" 80 " -u name\t\t\tunsetenv(name)\n", 81 basename(program)); 82 83 return; 84 } 85 86 87 /* 88 * Print the return value of a call along with errno upon error else zero. 89 * Also, use the eol string based upon whether running in test mode or not. 90 */ 91 static void 92 print_rtrn_errno(int rtrnVal, const char *eol) 93 { 94 printf("%d %d%s", rtrnVal, rtrnVal != 0 ? errno : 0, eol); 95 96 return; 97 } 98 99 static void 100 blank_env(const char *var) 101 { 102 char **newenviron; 103 int n, varlen; 104 105 if (environ == NULL) 106 return; 107 108 for (n = 0; environ[n] != NULL; n++) 109 ; 110 newenviron = malloc(sizeof(char *) * (n + 1)); 111 varlen = strlen(var); 112 for (; n >= 0; n--) { 113 newenviron[n] = environ[n]; 114 if (newenviron[n] != NULL && 115 strncmp(newenviron[n], var, varlen) == 0 && 116 newenviron[n][varlen] == '=') 117 newenviron[n] += strlen(newenviron[n]); 118 } 119 environ = newenviron; 120 } 121 122 int 123 main(int argc, char **argv) 124 { 125 char arg; 126 const char *eol = "\n"; 127 const char *value; 128 static char *emptyEnv[] = { NULL }; 129 static char *staticEnv[] = { "FOO=bar", NULL }; 130 131 if (argc == 1) { 132 usage(argv[0]); 133 exit(EXIT_FAILURE); 134 } 135 136 /* The entire program is basically executed from this loop. */ 137 while ((arg = getopt(argc, argv, "DGS:Ub:c:g:hp:rs:tu:")) != -1) { 138 switch (arg) { 139 case 'b': 140 blank_env(optarg); 141 break; 142 143 case 'c': 144 switch (atoi(optarg)) { 145 case 1: 146 environ = NULL; 147 break; 148 149 case 2: 150 environ[0] = NULL; 151 break; 152 153 case 3: 154 environ = calloc(1, sizeof(*environ)); 155 break; 156 157 case 4: 158 environ = emptyEnv; 159 break; 160 } 161 break; 162 163 case 'D': 164 dump_environ(); 165 break; 166 167 case 'G': 168 case 'g': 169 value = getenv(arg == 'g' ? optarg : NULL); 170 printf("%s%s", value == NULL ? "*NULL*" : value, eol); 171 break; 172 173 case 'p': 174 print_rtrn_errno(putenv(optarg), eol); 175 break; 176 177 case 'r': 178 environ = staticEnv; 179 break; 180 181 case 'S': 182 print_rtrn_errno(setenv(NULL, optarg, 183 atoi(argv[optind])), eol); 184 optind += 1; 185 break; 186 187 case 's': 188 print_rtrn_errno(setenv(optarg, argv[optind], 189 atoi(argv[optind + 1])), eol); 190 optind += 2; 191 break; 192 193 case 't': 194 eol = " "; 195 break; 196 197 case 'U': 198 case 'u': 199 print_rtrn_errno(unsetenv(arg == 'u' ? optarg : NULL), 200 eol); 201 break; 202 203 case 'h': 204 default: 205 usage(argv[0]); 206 exit(EXIT_FAILURE); 207 } 208 } 209 210 /* Output a closing newline in test mode. */ 211 if (eol[0] == ' ') 212 printf("\n"); 213 214 return (EXIT_SUCCESS); 215 } 216