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1 | /* |
2 | * lxc: linux Container library | |
3 | * | |
4 | * (C) Copyright IBM Corp. 2007, 2008 | |
5 | * | |
6 | * Authors: | |
7 | * Daniel Lezcano <daniel.lezcano at free.fr> | |
8 | * | |
9 | * This library is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU Lesser General Public | |
11 | * License as published by the Free Software Foundation; either | |
12 | * version 2.1 of the License, or (at your option) any later version. | |
13 | * | |
14 | * This library is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
17 | * Lesser General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU Lesser General Public | |
20 | * License along with this library; if not, write to the Free Software | |
21 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
22 | */ | |
23 | ||
24 | #include "initutils.h" | |
25 | #include "log.h" | |
26 | ||
27 | lxc_log_define(lxc_initutils, lxc); | |
28 | ||
29 | static int mount_fs(const char *source, const char *target, const char *type) | |
30 | { | |
31 | /* the umount may fail */ | |
32 | if (umount(target)) | |
33 | WARN("failed to unmount %s : %s", target, strerror(errno)); | |
34 | ||
35 | if (mount(source, target, type, 0, NULL)) { | |
36 | ERROR("failed to mount %s : %s", target, strerror(errno)); | |
37 | return -1; | |
38 | } | |
39 | ||
40 | DEBUG("'%s' mounted on '%s'", source, target); | |
41 | ||
42 | return 0; | |
43 | } | |
44 | ||
45 | extern void lxc_setup_fs(void) | |
46 | { | |
47 | if (mount_fs("proc", "/proc", "proc")) | |
48 | INFO("failed to remount proc"); | |
49 | ||
50 | /* if we can't mount /dev/shm, continue anyway */ | |
51 | if (mount_fs("shmfs", "/dev/shm", "tmpfs")) | |
52 | INFO("failed to mount /dev/shm"); | |
53 | ||
54 | /* If we were able to mount /dev/shm, then /dev exists */ | |
55 | /* Sure, but it's read-only per config :) */ | |
56 | if (access("/dev/mqueue", F_OK) && mkdir("/dev/mqueue", 0666)) { | |
57 | DEBUG("failed to create '/dev/mqueue'"); | |
58 | return; | |
59 | } | |
60 | ||
61 | /* continue even without posix message queue support */ | |
62 | if (mount_fs("mqueue", "/dev/mqueue", "mqueue")) | |
63 | INFO("failed to mount /dev/mqueue"); | |
64 | } | |
65 | ||
66 | static char *copy_global_config_value(char *p) | |
67 | { | |
68 | int len = strlen(p); | |
69 | char *retbuf; | |
70 | ||
71 | if (len < 1) | |
72 | return NULL; | |
73 | if (p[len-1] == '\n') { | |
74 | p[len-1] = '\0'; | |
75 | len--; | |
76 | } | |
77 | retbuf = malloc(len+1); | |
78 | if (!retbuf) | |
79 | return NULL; | |
80 | strcpy(retbuf, p); | |
81 | return retbuf; | |
82 | } | |
83 | ||
84 | const char *lxc_global_config_value(const char *option_name) | |
85 | { | |
86 | static const char * const options[][2] = { | |
87 | { "lxc.bdev.lvm.vg", DEFAULT_VG }, | |
88 | { "lxc.bdev.lvm.thin_pool", DEFAULT_THIN_POOL }, | |
89 | { "lxc.bdev.zfs.root", DEFAULT_ZFSROOT }, | |
90 | { "lxc.lxcpath", NULL }, | |
91 | { "lxc.default_config", NULL }, | |
92 | { "lxc.cgroup.pattern", NULL }, | |
93 | { "lxc.cgroup.use", NULL }, | |
94 | { NULL, NULL }, | |
95 | }; | |
96 | ||
97 | /* placed in the thread local storage pool for non-bionic targets */ | |
98 | #ifdef HAVE_TLS | |
99 | static __thread const char *values[sizeof(options) / sizeof(options[0])] = { 0 }; | |
100 | #else | |
101 | static const char *values[sizeof(options) / sizeof(options[0])] = { 0 }; | |
102 | #endif | |
103 | ||
104 | /* user_config_path is freed as soon as it is used */ | |
105 | char *user_config_path = NULL; | |
106 | ||
107 | /* | |
108 | * The following variables are freed at bottom unconditionally. | |
109 | * So NULL the value if it is to be returned to the caller | |
110 | */ | |
111 | char *user_default_config_path = NULL; | |
112 | char *user_lxc_path = NULL; | |
113 | char *user_cgroup_pattern = NULL; | |
114 | ||
115 | if (geteuid() > 0) { | |
116 | const char *user_home = getenv("HOME"); | |
117 | if (!user_home) | |
118 | user_home = "/"; | |
119 | ||
120 | user_config_path = malloc(sizeof(char) * (22 + strlen(user_home))); | |
121 | user_default_config_path = malloc(sizeof(char) * (26 + strlen(user_home))); | |
122 | user_lxc_path = malloc(sizeof(char) * (19 + strlen(user_home))); | |
123 | ||
124 | sprintf(user_config_path, "%s/.config/lxc/lxc.conf", user_home); | |
125 | sprintf(user_default_config_path, "%s/.config/lxc/default.conf", user_home); | |
126 | sprintf(user_lxc_path, "%s/.local/share/lxc/", user_home); | |
127 | user_cgroup_pattern = strdup("lxc/%n"); | |
128 | } | |
129 | else { | |
130 | user_config_path = strdup(LXC_GLOBAL_CONF); | |
131 | user_default_config_path = strdup(LXC_DEFAULT_CONFIG); | |
132 | user_lxc_path = strdup(LXCPATH); | |
133 | user_cgroup_pattern = strdup(DEFAULT_CGROUP_PATTERN); | |
134 | } | |
135 | ||
136 | const char * const (*ptr)[2]; | |
137 | size_t i; | |
138 | char buf[1024], *p, *p2; | |
139 | FILE *fin = NULL; | |
140 | ||
141 | for (i = 0, ptr = options; (*ptr)[0]; ptr++, i++) { | |
142 | if (!strcmp(option_name, (*ptr)[0])) | |
143 | break; | |
144 | } | |
145 | if (!(*ptr)[0]) { | |
146 | free(user_config_path); | |
147 | free(user_default_config_path); | |
148 | free(user_lxc_path); | |
149 | free(user_cgroup_pattern); | |
150 | errno = EINVAL; | |
151 | return NULL; | |
152 | } | |
153 | ||
154 | if (values[i]) { | |
155 | free(user_config_path); | |
156 | free(user_default_config_path); | |
157 | free(user_lxc_path); | |
158 | free(user_cgroup_pattern); | |
159 | return values[i]; | |
160 | } | |
161 | ||
162 | fin = fopen_cloexec(user_config_path, "r"); | |
163 | free(user_config_path); | |
164 | if (fin) { | |
165 | while (fgets(buf, 1024, fin)) { | |
166 | if (buf[0] == '#') | |
167 | continue; | |
168 | p = strstr(buf, option_name); | |
169 | if (!p) | |
170 | continue; | |
171 | /* see if there was just white space in front | |
172 | * of the option name | |
173 | */ | |
174 | for (p2 = buf; p2 < p; p2++) { | |
175 | if (*p2 != ' ' && *p2 != '\t') | |
176 | break; | |
177 | } | |
178 | if (p2 < p) | |
179 | continue; | |
180 | p = strchr(p, '='); | |
181 | if (!p) | |
182 | continue; | |
183 | /* see if there was just white space after | |
184 | * the option name | |
185 | */ | |
186 | for (p2 += strlen(option_name); p2 < p; p2++) { | |
187 | if (*p2 != ' ' && *p2 != '\t') | |
188 | break; | |
189 | } | |
190 | if (p2 < p) | |
191 | continue; | |
192 | p++; | |
193 | while (*p && (*p == ' ' || *p == '\t')) p++; | |
194 | if (!*p) | |
195 | continue; | |
196 | ||
197 | if (strcmp(option_name, "lxc.lxcpath") == 0) { | |
198 | free(user_lxc_path); | |
199 | user_lxc_path = copy_global_config_value(p); | |
200 | remove_trailing_slashes(user_lxc_path); | |
201 | values[i] = user_lxc_path; | |
202 | user_lxc_path = NULL; | |
203 | goto out; | |
204 | } | |
205 | ||
206 | values[i] = copy_global_config_value(p); | |
207 | goto out; | |
208 | } | |
209 | } | |
210 | /* could not find value, use default */ | |
211 | if (strcmp(option_name, "lxc.lxcpath") == 0) { | |
212 | remove_trailing_slashes(user_lxc_path); | |
213 | values[i] = user_lxc_path; | |
214 | user_lxc_path = NULL; | |
215 | } | |
216 | else if (strcmp(option_name, "lxc.default_config") == 0) { | |
217 | values[i] = user_default_config_path; | |
218 | user_default_config_path = NULL; | |
219 | } | |
220 | else if (strcmp(option_name, "lxc.cgroup.pattern") == 0) { | |
221 | values[i] = user_cgroup_pattern; | |
222 | user_cgroup_pattern = NULL; | |
223 | } | |
224 | else | |
225 | values[i] = (*ptr)[1]; | |
226 | ||
227 | /* special case: if default value is NULL, | |
228 | * and there is no config, don't view that | |
229 | * as an error... */ | |
230 | if (!values[i]) | |
231 | errno = 0; | |
232 | ||
233 | out: | |
234 | if (fin) | |
235 | fclose(fin); | |
236 | ||
237 | free(user_cgroup_pattern); | |
238 | free(user_default_config_path); | |
239 | free(user_lxc_path); | |
240 | ||
241 | return values[i]; | |
242 | } | |
243 | ||
244 | extern void remove_trailing_slashes(char *p) | |
245 | { | |
246 | int l = strlen(p); | |
247 | while (--l >= 0 && (p[l] == '/' || p[l] == '\n')) | |
248 | p[l] = '\0'; | |
249 | } | |
250 | ||
251 | FILE *fopen_cloexec(const char *path, const char *mode) | |
252 | { | |
253 | int open_mode = 0; | |
254 | int step = 0; | |
255 | int fd; | |
256 | int saved_errno = 0; | |
257 | FILE *ret; | |
258 | ||
259 | if (!strncmp(mode, "r+", 2)) { | |
260 | open_mode = O_RDWR; | |
261 | step = 2; | |
262 | } else if (!strncmp(mode, "r", 1)) { | |
263 | open_mode = O_RDONLY; | |
264 | step = 1; | |
265 | } else if (!strncmp(mode, "w+", 2)) { | |
266 | open_mode = O_RDWR | O_TRUNC | O_CREAT; | |
267 | step = 2; | |
268 | } else if (!strncmp(mode, "w", 1)) { | |
269 | open_mode = O_WRONLY | O_TRUNC | O_CREAT; | |
270 | step = 1; | |
271 | } else if (!strncmp(mode, "a+", 2)) { | |
272 | open_mode = O_RDWR | O_CREAT | O_APPEND; | |
273 | step = 2; | |
274 | } else if (!strncmp(mode, "a", 1)) { | |
275 | open_mode = O_WRONLY | O_CREAT | O_APPEND; | |
276 | step = 1; | |
277 | } | |
278 | for (; mode[step]; step++) | |
279 | if (mode[step] == 'x') | |
280 | open_mode |= O_EXCL; | |
281 | open_mode |= O_CLOEXEC; | |
282 | ||
283 | fd = open(path, open_mode, 0666); | |
284 | if (fd < 0) | |
285 | return NULL; | |
286 | ||
287 | ret = fdopen(fd, mode); | |
288 | saved_errno = errno; | |
289 | if (!ret) | |
290 | close(fd); | |
291 | errno = saved_errno; | |
292 | return ret; | |
293 | } |