1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
#include <sys/queue.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "envlist.h"
struct envlist_entry {
const char *ev_var; /* actual env value */
LIST_ENTRY(envlist_entry) ev_link;
};
struct envlist {
LIST_HEAD(, envlist_entry) el_entries; /* actual entries */
size_t el_count; /* number of entries */
};
static int envlist_parse(envlist_t *envlist,
const char *env, int (*)(envlist_t *, const char *));
/*
* Allocates new envlist and returns pointer to that or
* NULL in case of error.
*/
envlist_t *
envlist_create(void)
{
envlist_t *envlist;
if ((envlist = malloc(sizeof (*envlist))) == NULL)
return (NULL);
LIST_INIT(&envlist->el_entries);
envlist->el_count = 0;
return (envlist);
}
/*
* Releases given envlist and its entries.
*/
void
envlist_free(envlist_t *envlist)
{
struct envlist_entry *entry;
assert(envlist != NULL);
while (envlist->el_entries.lh_first != NULL) {
entry = envlist->el_entries.lh_first;
LIST_REMOVE(entry, ev_link);
free((char *)entry->ev_var);
free(entry);
}
free(envlist);
}
/*
* Parses comma separated list of set/modify environment
* variable entries and updates given enlist accordingly.
*
* For example:
* envlist_parse(el, "HOME=foo,SHELL=/bin/sh");
*
* inserts/sets environment variables HOME and SHELL.
*
* Returns 0 on success, errno otherwise.
*/
int
envlist_parse_set(envlist_t *envlist, const char *env)
{
return (envlist_parse(envlist, env, &envlist_setenv));
}
/*
* Parses comma separated list of unset environment variable
* entries and removes given variables from given envlist.
*
* Returns 0 on success, errno otherwise.
*/
int
envlist_parse_unset(envlist_t *envlist, const char *env)
{
return (envlist_parse(envlist, env, &envlist_unsetenv));
}
/*
* Parses comma separated list of set, modify or unset entries
* and calls given callback for each entry.
*
* Returns 0 in case of success, errno otherwise.
*/
static int
envlist_parse(envlist_t *envlist, const char *env,
int (*callback)(envlist_t *, const char *))
{
char *tmpenv, *envvar;
char *envsave = NULL;
assert(callback != NULL);
if ((envlist == NULL) || (env == NULL))
return (EINVAL);
/*
* We need to make temporary copy of the env string
* as strtok_r(3) modifies it while it tokenizes.
*/
if ((tmpenv = strdup(env)) == NULL)
return (errno);
envvar = strtok_r(tmpenv, ",", &envsave);
while (envvar != NULL) {
if ((*callback)(envlist, envvar) != 0) {
free(tmpenv);
return (errno);
}
envvar = strtok_r(NULL, ",", &envsave);
}
free(tmpenv);
return (0);
}
/*
* Sets environment value to envlist in similar manner
* than putenv(3).
*
* Returns 0 in success, errno otherwise.
*/
int
envlist_setenv(envlist_t *envlist, const char *env)
{
struct envlist_entry *entry = NULL;
const char *eq_sign;
size_t envname_len;
if ((envlist == NULL) || (env == NULL))
return (EINVAL);
/* find out first equals sign in given env */
if ((eq_sign = strchr(env, '=')) == NULL)
return (EINVAL);
envname_len = eq_sign - env + 1;
/*
* If there already exists variable with given name
* we remove and release it before allocating a whole
* new entry.
*/
for (entry = envlist->el_entries.lh_first; entry != NULL;
entry = entry->ev_link.le_next) {
if (strncmp(entry->ev_var, env, envname_len) == 0)
break;
}
if (entry != NULL) {
LIST_REMOVE(entry, ev_link);
free((char *)entry->ev_var);
free(entry);
} else {
envlist->el_count++;
}
if ((entry = malloc(sizeof (*entry))) == NULL)
return (errno);
if ((entry->ev_var = strdup(env)) == NULL) {
free(entry);
return (errno);
}
LIST_INSERT_HEAD(&envlist->el_entries, entry, ev_link);
return (0);
}
/*
* Removes given env value from envlist in similar manner
* than unsetenv(3). Returns 0 in success, errno otherwise.
*/
int
envlist_unsetenv(envlist_t *envlist, const char *env)
{
struct envlist_entry *entry;
size_t envname_len;
if ((envlist == NULL) || (env == NULL))
return (EINVAL);
/* env is not allowed to contain '=' */
if (strchr(env, '=') != NULL)
return (EINVAL);
/*
* Find out the requested entry and remove
* it from the list.
*/
envname_len = strlen(env);
for (entry = envlist->el_entries.lh_first; entry != NULL;
entry = entry->ev_link.le_next) {
if (strncmp(entry->ev_var, env, envname_len) == 0)
break;
}
if (entry != NULL) {
LIST_REMOVE(entry, ev_link);
free((char *)entry->ev_var);
free(entry);
envlist->el_count--;
}
return (0);
}
/*
* Returns given envlist as array of strings (in same form that
* global variable environ is). Caller must free returned memory
* by calling free(3) for each element and for the array. Returned
* array and given envlist are not related (no common references).
*
* If caller provides count pointer, number of items in array is
* stored there. In case of error, NULL is returned and no memory
* is allocated.
*/
char **
envlist_to_environ(const envlist_t *envlist, size_t *count)
{
struct envlist_entry *entry;
char **env, **penv;
penv = env = malloc((envlist->el_count + 1) * sizeof (char *));
if (env == NULL)
return (NULL);
for (entry = envlist->el_entries.lh_first; entry != NULL;
entry = entry->ev_link.le_next) {
*(penv++) = strdup(entry->ev_var);
}
*penv = NULL; /* NULL terminate the list */
if (count != NULL)
*count = envlist->el_count;
return (env);
}
|
