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
dump_environ(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
usage(const char * program)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
print_rtrn_errno(int rtrnVal,const char * eol)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
blank_env(const char * var)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
main(int argc,char ** argv)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