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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2012 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <limits.h> | |
23 | #include <sys/param.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | #include "strv.h" | |
27 | #include "utf8.h" | |
28 | #include "util.h" | |
29 | #include "env-util.h" | |
30 | ||
31 | #define VALID_CHARS_ENV_NAME \ | |
32 | "0123456789" \ | |
33 | "abcdefghijklmnopqrstuvwxyz" \ | |
34 | "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \ | |
35 | "_" | |
36 | ||
37 | #ifndef ARG_MAX | |
38 | #define ARG_MAX ((size_t) sysconf(_SC_ARG_MAX)) | |
39 | #endif | |
40 | ||
41 | static bool env_name_is_valid_n(const char *e, size_t n) { | |
42 | const char *p; | |
43 | ||
44 | if (!e) | |
45 | return false; | |
46 | ||
47 | if (n <= 0) | |
48 | return false; | |
49 | ||
50 | if (e[0] >= '0' && e[0] <= '9') | |
51 | return false; | |
52 | ||
53 | /* POSIX says the overall size of the environment block cannot | |
54 | * be > ARG_MAX, an individual assignment hence cannot be | |
55 | * either. Discounting the equal sign and trailing NUL this | |
56 | * hence leaves ARG_MAX-2 as longest possible variable | |
57 | * name. */ | |
58 | if (n > ARG_MAX - 2) | |
59 | return false; | |
60 | ||
61 | for (p = e; p < e + n; p++) | |
62 | if (!strchr(VALID_CHARS_ENV_NAME, *p)) | |
63 | return false; | |
64 | ||
65 | return true; | |
66 | } | |
67 | ||
68 | bool env_name_is_valid(const char *e) { | |
69 | if (!e) | |
70 | return false; | |
71 | ||
72 | return env_name_is_valid_n(e, strlen(e)); | |
73 | } | |
74 | ||
75 | bool env_value_is_valid(const char *e) { | |
76 | if (!e) | |
77 | return false; | |
78 | ||
79 | if (!utf8_is_valid(e)) | |
80 | return false; | |
81 | ||
82 | if (string_has_cc(e)) | |
83 | return false; | |
84 | ||
85 | /* POSIX says the overall size of the environment block cannot | |
86 | * be > ARG_MAX, an individual assignment hence cannot be | |
87 | * either. Discounting the shortest possible variable name of | |
88 | * length 1, the equal sign and trailing NUL this hence leaves | |
89 | * ARG_MAX-3 as longest possible variable value. */ | |
90 | if (strlen(e) > ARG_MAX - 3) | |
91 | return false; | |
92 | ||
93 | return true; | |
94 | } | |
95 | ||
96 | bool env_assignment_is_valid(const char *e) { | |
97 | const char *eq; | |
98 | ||
99 | eq = strchr(e, '='); | |
100 | if (!eq) | |
101 | return false; | |
102 | ||
103 | if (!env_name_is_valid_n(e, eq - e)) | |
104 | return false; | |
105 | ||
106 | if (!env_value_is_valid(eq + 1)) | |
107 | return false; | |
108 | ||
109 | /* POSIX says the overall size of the environment block cannot | |
110 | * be > ARG_MAX, hence the individual variable assignments | |
111 | * cannot be either, but let's room for one trailing NUL | |
112 | * byte. */ | |
113 | if (strlen(e) > ARG_MAX - 1) | |
114 | return false; | |
115 | ||
116 | return true; | |
117 | } | |
118 | ||
119 | bool strv_env_is_valid(char **e) { | |
120 | char **p, **q; | |
121 | ||
122 | STRV_FOREACH(p, e) { | |
123 | size_t k; | |
124 | ||
125 | if (!env_assignment_is_valid(*p)) | |
126 | return false; | |
127 | ||
128 | /* Check if there are duplicate assginments */ | |
129 | k = strcspn(*p, "="); | |
130 | STRV_FOREACH(q, p + 1) | |
131 | if (strncmp(*p, *q, k) == 0 && (*q)[k] == '=') | |
132 | return false; | |
133 | } | |
134 | ||
135 | return true; | |
136 | } | |
137 | ||
138 | static int env_append(char **r, char ***k, char **a) { | |
139 | assert(r); | |
140 | assert(k); | |
141 | ||
142 | if (!a) | |
143 | return 0; | |
144 | ||
145 | /* Add the entries of a to *k unless they already exist in *r | |
146 | * in which case they are overridden instead. This assumes | |
147 | * there is enough space in the r array. */ | |
148 | ||
149 | for (; *a; a++) { | |
150 | char **j; | |
151 | size_t n; | |
152 | ||
153 | n = strcspn(*a, "="); | |
154 | ||
155 | if ((*a)[n] == '=') | |
156 | n++; | |
157 | ||
158 | for (j = r; j < *k; j++) | |
159 | if (strncmp(*j, *a, n) == 0) | |
160 | break; | |
161 | ||
162 | if (j >= *k) | |
163 | (*k)++; | |
164 | else | |
165 | free(*j); | |
166 | ||
167 | *j = strdup(*a); | |
168 | if (!*j) | |
169 | return -ENOMEM; | |
170 | } | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
175 | char **strv_env_merge(unsigned n_lists, ...) { | |
176 | size_t n = 0; | |
177 | char **l, **k, **r; | |
178 | va_list ap; | |
179 | unsigned i; | |
180 | ||
181 | /* Merges an arbitrary number of environment sets */ | |
182 | ||
183 | va_start(ap, n_lists); | |
184 | for (i = 0; i < n_lists; i++) { | |
185 | l = va_arg(ap, char**); | |
186 | n += strv_length(l); | |
187 | } | |
188 | va_end(ap); | |
189 | ||
190 | r = new(char*, n+1); | |
191 | if (!r) | |
192 | return NULL; | |
193 | ||
194 | k = r; | |
195 | ||
196 | va_start(ap, n_lists); | |
197 | for (i = 0; i < n_lists; i++) { | |
198 | l = va_arg(ap, char**); | |
199 | if (env_append(r, &k, l) < 0) | |
200 | goto fail; | |
201 | } | |
202 | va_end(ap); | |
203 | ||
204 | *k = NULL; | |
205 | ||
206 | return r; | |
207 | ||
208 | fail: | |
209 | va_end(ap); | |
210 | strv_free(r); | |
211 | ||
212 | return NULL; | |
213 | } | |
214 | ||
215 | static bool env_match(const char *t, const char *pattern) { | |
216 | assert(t); | |
217 | assert(pattern); | |
218 | ||
219 | /* pattern a matches string a | |
220 | * a matches a= | |
221 | * a matches a=b | |
222 | * a= matches a= | |
223 | * a=b matches a=b | |
224 | * a= does not match a | |
225 | * a=b does not match a= | |
226 | * a=b does not match a | |
227 | * a=b does not match a=c */ | |
228 | ||
229 | if (streq(t, pattern)) | |
230 | return true; | |
231 | ||
232 | if (!strchr(pattern, '=')) { | |
233 | size_t l = strlen(pattern); | |
234 | ||
235 | return strncmp(t, pattern, l) == 0 && t[l] == '='; | |
236 | } | |
237 | ||
238 | return false; | |
239 | } | |
240 | ||
241 | char **strv_env_delete(char **x, unsigned n_lists, ...) { | |
242 | size_t n, i = 0; | |
243 | char **k, **r; | |
244 | va_list ap; | |
245 | ||
246 | /* Deletes every entry from x that is mentioned in the other | |
247 | * string lists */ | |
248 | ||
249 | n = strv_length(x); | |
250 | ||
251 | r = new(char*, n+1); | |
252 | if (!r) | |
253 | return NULL; | |
254 | ||
255 | STRV_FOREACH(k, x) { | |
256 | unsigned v; | |
257 | ||
258 | va_start(ap, n_lists); | |
259 | for (v = 0; v < n_lists; v++) { | |
260 | char **l, **j; | |
261 | ||
262 | l = va_arg(ap, char**); | |
263 | STRV_FOREACH(j, l) | |
264 | if (env_match(*k, *j)) | |
265 | goto skip; | |
266 | } | |
267 | va_end(ap); | |
268 | ||
269 | r[i] = strdup(*k); | |
270 | if (!r[i]) { | |
271 | strv_free(r); | |
272 | return NULL; | |
273 | } | |
274 | ||
275 | i++; | |
276 | continue; | |
277 | ||
278 | skip: | |
279 | va_end(ap); | |
280 | } | |
281 | ||
282 | r[i] = NULL; | |
283 | ||
284 | assert(i <= n); | |
285 | ||
286 | return r; | |
287 | } | |
288 | ||
289 | char **strv_env_unset(char **l, const char *p) { | |
290 | ||
291 | char **f, **t; | |
292 | ||
293 | if (!l) | |
294 | return NULL; | |
295 | ||
296 | assert(p); | |
297 | ||
298 | /* Drops every occurrence of the env var setting p in the | |
299 | * string list. edits in-place. */ | |
300 | ||
301 | for (f = t = l; *f; f++) { | |
302 | ||
303 | if (env_match(*f, p)) { | |
304 | free(*f); | |
305 | continue; | |
306 | } | |
307 | ||
308 | *(t++) = *f; | |
309 | } | |
310 | ||
311 | *t = NULL; | |
312 | return l; | |
313 | } | |
314 | ||
315 | char **strv_env_set(char **x, const char *p) { | |
316 | ||
317 | char **k, **r; | |
318 | char* m[2] = { (char*) p, NULL }; | |
319 | ||
320 | /* Overrides the env var setting of p, returns a new copy */ | |
321 | ||
322 | r = new(char*, strv_length(x)+2); | |
323 | if (!r) | |
324 | return NULL; | |
325 | ||
326 | k = r; | |
327 | if (env_append(r, &k, x) < 0) | |
328 | goto fail; | |
329 | ||
330 | if (env_append(r, &k, m) < 0) | |
331 | goto fail; | |
332 | ||
333 | *k = NULL; | |
334 | ||
335 | return r; | |
336 | ||
337 | fail: | |
338 | strv_free(r); | |
339 | return NULL; | |
340 | } | |
341 | ||
342 | char *strv_env_get_n(char **l, const char *name, size_t k) { | |
343 | char **i; | |
344 | ||
345 | assert(name); | |
346 | ||
347 | if (k <= 0) | |
348 | return NULL; | |
349 | ||
350 | STRV_FOREACH(i, l) | |
351 | if (strncmp(*i, name, k) == 0 && | |
352 | (*i)[k] == '=') | |
353 | return *i + k + 1; | |
354 | ||
355 | return NULL; | |
356 | } | |
357 | ||
358 | char *strv_env_get(char **l, const char *name) { | |
359 | assert(name); | |
360 | ||
361 | return strv_env_get_n(l, name, strlen(name)); | |
362 | } | |
363 | ||
364 | char **strv_env_clean(char **e) { | |
365 | char **p, **q; | |
366 | int k = 0; | |
367 | ||
368 | STRV_FOREACH(p, e) { | |
369 | size_t n; | |
370 | bool duplicate = false; | |
371 | ||
372 | if (!env_assignment_is_valid(*p)) { | |
373 | free(*p); | |
374 | continue; | |
375 | } | |
376 | ||
377 | n = strcspn(*p, "="); | |
378 | STRV_FOREACH(q, p + 1) | |
379 | if (strncmp(*p, *q, n) == 0 && (*q)[n] == '=') { | |
380 | duplicate = true; | |
381 | break; | |
382 | } | |
383 | ||
384 | if (duplicate) { | |
385 | free(*p); | |
386 | continue; | |
387 | } | |
388 | ||
389 | e[k++] = *p; | |
390 | } | |
391 | ||
392 | e[k] = NULL; | |
393 | return e; | |
394 | } |