]>
git.proxmox.com Git - mirror_lxc.git/blob - src/lxc/lxccontainer.c
3 * Copyright © 2012 Serge Hallyn <serge.hallyn@ubuntu.com>.
4 * Copyright © 2012 Canonical Ltd.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2, as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22 #include "lxccontainer.h"
30 #include <sys/types.h>
33 #include <lxc/utils.h>
35 lxc_log_define(lxc_container
, lxc
);
38 * c->privlock protects the struct lxc_container from multiple threads.
39 * c->slock protects the on-disk container data
40 * NOTHING mutexes two independent programs with their own struct
41 * lxc_container for the same c->name, between API calls. For instance,
42 * c->config_read(); c->start(); Between those calls, data on disk
43 * could change (which shouldn't bother the caller unless for instance
44 * the rootfs get moved). c->config_read(); update; c->config_write();
45 * Two such updaters could race. The callers should therefore check their
46 * results. Trying to prevent that would necessarily expose us to deadlocks
47 * due to hung callers. So I prefer to keep the locks only within our own
48 * functions, not across functions.
50 * If you're going to fork while holding a lxccontainer, increment
51 * c->numthreads (under privlock) before forking. When deleting,
52 * decrement numthreads under privlock, then if it hits 0 you can delete.
53 * Do not ever use a lxccontainer whose numthreads you did not bump.
56 static void lxc_container_free(struct lxc_container
*c
)
65 if (c
->error_string
) {
66 free(c
->error_string
);
67 c
->error_string
= NULL
;
74 sem_destroy(c
->privlock
);
83 lxc_conf_free(c
->lxc_conf
);
88 c
->config_path
= NULL
;
93 int lxc_container_get(struct lxc_container
*c
)
98 if (lxclock(c
->privlock
, 0))
100 if (c
->numthreads
< 1) {
101 // bail without trying to unlock, bc the privlock is now probably
106 lxcunlock(c
->privlock
);
110 int lxc_container_put(struct lxc_container
*c
)
114 if (lxclock(c
->privlock
, 0))
116 if (--c
->numthreads
< 1) {
117 lxcunlock(c
->privlock
);
118 lxc_container_free(c
);
121 lxcunlock(c
->privlock
);
125 static bool file_exists(char *f
)
129 return stat(f
, &statbuf
) == 0;
132 static bool lxcapi_is_defined(struct lxc_container
*c
)
141 if (lxclock(c
->privlock
, 0))
145 statret
= stat(c
->configfile
, &statbuf
);
151 lxcunlock(c
->privlock
);
155 static const char *lxcapi_state(struct lxc_container
*c
)
162 if (lxclock(c
->slock
, 0))
164 s
= lxc_getstate(c
->name
, c
->config_path
);
165 ret
= lxc_state2str(s
);
171 static bool is_stopped_nolock(struct lxc_container
*c
)
174 s
= lxc_getstate(c
->name
, c
->config_path
);
175 return (s
== STOPPED
);
178 static bool lxcapi_is_running(struct lxc_container
*c
)
185 if (!s
|| strcmp(s
, "STOPPED") == 0)
190 static bool lxcapi_freeze(struct lxc_container
*c
)
196 if (lxclock(c
->slock
, 0))
198 ret
= lxc_freeze(c
->name
);
205 static bool lxcapi_unfreeze(struct lxc_container
*c
)
211 if (lxclock(c
->slock
, 0))
213 ret
= lxc_unfreeze(c
->name
);
220 static pid_t
lxcapi_init_pid(struct lxc_container
*c
)
226 if (lxclock(c
->slock
, 0))
228 ret
= get_init_pid(c
->name
, c
->config_path
);
233 static bool load_config_locked(struct lxc_container
*c
, const char *fname
)
236 c
->lxc_conf
= lxc_conf_init();
237 if (c
->lxc_conf
&& !lxc_config_read(fname
, c
->lxc_conf
))
242 static bool lxcapi_load_config(struct lxc_container
*c
, const char *alt_file
)
249 fname
= c
->configfile
;
254 if (lxclock(c
->slock
, 0))
256 ret
= load_config_locked(c
, fname
);
261 static void lxcapi_want_daemonize(struct lxc_container
*c
)
268 static bool lxcapi_wait(struct lxc_container
*c
, const char *state
, int timeout
)
275 ret
= lxc_wait(c
->name
, state
, timeout
, c
->config_path
);
280 static bool wait_on_daemonized_start(struct lxc_container
*c
)
282 /* we'll probably want to make this timeout configurable? */
283 int timeout
= 5, ret
, status
;
286 * our child is going to fork again, then exit. reap the
290 if (ret
== -1 || !WIFEXITED(status
) || WEXITSTATUS(status
) != 0)
291 DEBUG("failed waiting for first dual-fork child");
292 return lxcapi_wait(c
, "RUNNING", timeout
);
296 * I can't decide if it'd be more convenient for callers if we accept '...',
297 * or a null-terminated array (i.e. execl vs execv)
299 static bool lxcapi_start(struct lxc_container
*c
, int useinit
, char * const argv
[])
302 struct lxc_conf
*conf
;
304 char *default_args
[] = {
309 /* container exists */
312 /* container has been setup */
316 /* is this app meant to be run through lxcinit, as in lxc-execute? */
317 if (useinit
&& !argv
)
320 if (lxclock(c
->privlock
, 0))
323 daemonize
= c
->daemonize
;
324 lxcunlock(c
->privlock
);
327 ret
= lxc_execute(c
->name
, argv
, 1, conf
, c
->config_path
);
328 return ret
== 0 ? true : false;
335 * say, I'm not sure - what locks do we want here? Any?
336 * Is liblxc's locking enough here to protect the on disk
337 * container? We don't want to exclude things like lxc_info
338 * while container is running...
341 if (!lxc_container_get(c
))
345 lxc_container_put(c
);
349 return wait_on_daemonized_start(c
);
350 /* second fork to be reparented by init */
353 SYSERROR("Error doing dual-fork");
358 /* like daemon(), chdir to / and redirect 0,1,2 to /dev/null */
360 SYSERROR("Error chdir()ing to /.");
366 open("/dev/null", O_RDONLY
);
367 open("/dev/null", O_RDWR
);
368 open("/dev/null", O_RDWR
);
373 SYSERROR("failed to clear environment");
374 /* don't error out though */
377 if (putenv("container=lxc")) {
378 fprintf(stderr
, "failed to set environment variable");
380 lxc_container_put(c
);
389 ret
= lxc_start(c
->name
, argv
, conf
, c
->config_path
);
392 INFO("container requested reboot");
398 lxc_container_put(c
);
399 exit (ret
== 0 ? true : false);
401 return (ret
== 0 ? true : false);
406 * note there MUST be an ending NULL
408 static bool lxcapi_startl(struct lxc_container
*c
, int useinit
, ...)
411 char **inargs
= NULL
, **temp
;
415 /* container exists */
419 /* build array of arguments if any */
420 va_start(ap
, useinit
);
423 arg
= va_arg(ap
, char *);
427 temp
= realloc(inargs
, n_inargs
* sizeof(*inargs
));
431 inargs
[n_inargs
- 1] = strdup(arg
); // not sure if it's safe not to copy
435 /* add trailing NULL */
438 temp
= realloc(inargs
, n_inargs
* sizeof(*inargs
));
442 inargs
[n_inargs
- 1] = NULL
;
445 bret
= lxcapi_start(c
, useinit
, inargs
);
450 for (i
= 0; i
< n_inargs
; i
++) {
460 static bool lxcapi_stop(struct lxc_container
*c
)
467 ret
= lxc_stop(c
->name
, c
->config_path
);
472 static bool valid_template(char *t
)
477 statret
= stat(t
, &statbuf
);
484 * create the standard expected container dir
486 static bool create_container_dir(struct lxc_container
*c
)
491 len
= strlen(c
->config_path
) + strlen(c
->name
) + 2;
495 ret
= snprintf(s
, len
, "%s/%s", c
->config_path
, c
->name
);
496 if (ret
< 0 || ret
>= len
) {
500 ret
= mkdir(s
, 0755);
505 SYSERROR("failed to create container path for %s\n", c
->name
);
512 * backing stores not (yet) supported
513 * for ->create, argv contains the arguments to pass to the template,
514 * terminated by NULL. If no arguments, you can just pass NULL.
516 static bool lxcapi_create(struct lxc_container
*c
, char *t
, char *const argv
[])
528 len
= strlen(LXCTEMPLATEDIR
) + strlen(t
) + strlen("/lxc-") + 1;
532 ret
= snprintf(tpath
, len
, "%s/lxc-%s", LXCTEMPLATEDIR
, t
);
533 if (ret
< 0 || ret
>= len
)
535 if (!valid_template(tpath
)) {
536 ERROR("bad template: %s\n", t
);
540 if (!create_container_dir(c
))
543 if (!c
->save_config(c
, NULL
)) {
544 ERROR("failed to save starting configuration for %s\n", c
->name
);
548 /* we're going to fork. but since we'll wait for our child, we
549 don't need to lxc_container_get */
551 if (lxclock(c
->slock
, 0)) {
552 ERROR("failed to grab global container lock for %s\n", c
->name
);
558 SYSERROR("failed to fork task for container creation template\n");
562 if (pid
== 0) { // child
563 char *patharg
, *namearg
;
569 open("/dev/null", O_RDONLY
);
570 open("/dev/null", O_RDWR
);
571 open("/dev/null", O_RDWR
);
574 * create our new array, pre-pend the template name and
578 for (; argv
[nargs
]; nargs
++) ;
579 nargs
+= 3; // template, path and name args
580 newargv
= malloc(nargs
* sizeof(*newargv
));
585 len
= strlen(c
->config_path
) + strlen(c
->name
) + strlen("--path=") + 2;
586 patharg
= malloc(len
);
589 ret
= snprintf(patharg
, len
, "--path=%s/%s", c
->config_path
, c
->name
);
590 if (ret
< 0 || ret
>= len
)
592 newargv
[1] = patharg
;
593 len
= strlen("--name=") + strlen(c
->name
) + 1;
594 namearg
= malloc(len
);
597 ret
= snprintf(namearg
, len
, "--name=%s", c
->name
);
598 if (ret
< 0 || ret
>= len
)
600 newargv
[2] = namearg
;
602 /* add passed-in args */
604 for (i
= 3; i
< nargs
; i
++)
605 newargv
[i
] = argv
[i
-3];
607 /* add trailing NULL */
609 newargv
= realloc(newargv
, nargs
* sizeof(*newargv
));
612 newargv
[nargs
- 1] = NULL
;
615 ret
= execv(tpath
, newargv
);
616 SYSERROR("failed to execute template %s", tpath
);
621 ret
= waitpid(pid
, &status
, 0);
625 SYSERROR("waitpid failed");
630 if (!WIFEXITED(status
)) { // did not exit normally
631 // we could set an error code and string inside the
632 // container_struct here if we like
633 ERROR("container creation template exited abnormally\n");
637 if (WEXITSTATUS(status
) != 0) {
638 ERROR("container creation template for %s exited with %d\n",
639 c
->name
, WEXITSTATUS(status
));
643 // now clear out the lxc_conf we have, reload from the created
646 lxc_conf_free(c
->lxc_conf
);
648 bret
= load_config_locked(c
, c
->configfile
);
658 static bool lxcapi_shutdown(struct lxc_container
*c
, int timeout
)
668 if (!c
->is_running(c
))
670 pid
= c
->init_pid(c
);
674 retv
= c
->wait(c
, "STOPPED", timeout
);
675 if (!retv
&& timeout
> 0) {
677 retv
= c
->wait(c
, "STOPPED", 0); // 0 means don't wait
682 static bool lxcapi_createl(struct lxc_container
*c
, char *t
, ...)
685 char **args
= NULL
, **temp
;
693 * since we're going to wait for create to finish, I don't think we
694 * need to get a copy of the arguments.
699 arg
= va_arg(ap
, char *);
703 temp
= realloc(args
, (nargs
+1) * sizeof(*args
));
707 args
[nargs
- 1] = arg
;
712 bret
= c
->create(c
, t
, args
);
720 static bool lxcapi_clear_config_item(struct lxc_container
*c
, const char *key
)
724 if (!c
|| !c
->lxc_conf
)
726 if (lxclock(c
->privlock
, 0)) {
729 ret
= lxc_clear_config_item(c
->lxc_conf
, key
);
730 lxcunlock(c
->privlock
);
734 static int lxcapi_get_config_item(struct lxc_container
*c
, const char *key
, char *retv
, int inlen
)
738 if (!c
|| !c
->lxc_conf
)
740 if (lxclock(c
->privlock
, 0)) {
743 ret
= lxc_get_config_item(c
->lxc_conf
, key
, retv
, inlen
);
744 lxcunlock(c
->privlock
);
748 static int lxcapi_get_keys(struct lxc_container
*c
, const char *key
, char *retv
, int inlen
)
751 return lxc_listconfigs(retv
, inlen
);
753 * Support 'lxc.network.<idx>', i.e. 'lxc.network.0'
754 * This is an intelligent result to show which keys are valid given
755 * the type of nic it is
757 if (!c
|| !c
->lxc_conf
)
759 if (lxclock(c
->privlock
, 0))
762 if (strncmp(key
, "lxc.network.", 12) == 0)
763 ret
= lxc_list_nicconfigs(c
->lxc_conf
, key
, retv
, inlen
);
764 lxcunlock(c
->privlock
);
769 /* default config file - should probably come through autoconf */
770 #define LXC_DEFAULT_CONFIG "/etc/lxc/default.conf"
771 static bool lxcapi_save_config(struct lxc_container
*c
, const char *alt_file
)
774 alt_file
= c
->configfile
;
776 return false; // should we write to stdout if no file is specified?
778 if (!c
->load_config(c
, LXC_DEFAULT_CONFIG
)) {
779 ERROR("Error loading default configuration file %s while saving %s\n", LXC_DEFAULT_CONFIG
, c
->name
);
783 FILE *fout
= fopen(alt_file
, "w");
786 if (lxclock(c
->privlock
, 0)) {
790 write_config(fout
, c
->lxc_conf
);
792 lxcunlock(c
->privlock
);
796 static bool lxcapi_destroy(struct lxc_container
*c
)
807 if (pid
== 0) { // child
808 ret
= execlp("lxc-destroy", "lxc-destroy", "-n", c
->name
, NULL
);
814 ret
= waitpid(pid
, &status
, 0);
823 if (!WIFEXITED(status
)) { // did not exit normally
824 // we could set an error code and string inside the
825 // container_struct here if we like
829 return WEXITSTATUS(status
) == 0;
832 static bool lxcapi_set_config_item(struct lxc_container
*c
, const char *key
, const char *v
)
836 struct lxc_config_t
*config
;
841 if (lxclock(c
->privlock
, 0))
845 c
->lxc_conf
= lxc_conf_init();
848 config
= lxc_getconfig(key
);
851 ret
= config
->cb(key
, v
, c
->lxc_conf
);
856 lxcunlock(c
->privlock
);
860 static char *lxcapi_config_file_name(struct lxc_container
*c
)
862 if (!c
|| !c
->configfile
)
864 return strdup(c
->configfile
);
867 static const char *lxcapi_get_config_path(struct lxc_container
*c
)
869 if (!c
|| !c
->config_path
)
871 return (const char *)(c
->config_path
);
876 * Just recalculate the c->configfile based on the
877 * c->config_path, which must be set.
878 * The lxc_container must be locked or not yet public.
880 static bool set_config_filename(struct lxc_container
*c
)
888 /* $lxc_path + "/" + c->name + "/" + "config" + '\0' */
889 len
= strlen(c
->config_path
) + strlen(c
->name
) + strlen("config") + 3;
890 newpath
= malloc(len
);
894 ret
= snprintf(newpath
, len
, "%s/%s/config", c
->config_path
, c
->name
);
895 if (ret
< 0 || ret
>= len
) {
896 fprintf(stderr
, "Error printing out config file name\n");
903 c
->configfile
= newpath
;
908 static bool lxcapi_set_config_path(struct lxc_container
*c
, const char *path
)
912 char *oldpath
= NULL
;
917 if (lxclock(c
->privlock
, 0))
922 ERROR("Out of memory setting new lxc path");
928 oldpath
= c
->config_path
;
931 /* Since we've changed the config path, we have to change the
932 * config file name too */
933 if (!set_config_filename(c
)) {
934 ERROR("Out of memory setting new config filename");
936 free(c
->config_path
);
937 c
->config_path
= oldpath
;
943 lxcunlock(c
->privlock
);
948 static bool lxcapi_set_cgroup_item(struct lxc_container
*c
, const char *subsys
, const char *value
)
956 if (lxclock(c
->privlock
, 0))
959 if (is_stopped_nolock(c
))
962 ret
= lxc_cgroup_set(c
->name
, subsys
, value
);
966 lxcunlock(c
->privlock
);
970 static int lxcapi_get_cgroup_item(struct lxc_container
*c
, const char *subsys
, char *retv
, int inlen
)
974 if (!c
|| !c
->lxc_conf
)
977 if (lxclock(c
->privlock
, 0))
980 if (is_stopped_nolock(c
))
983 ret
= lxc_cgroup_get(c
->name
, subsys
, retv
, inlen
);
986 lxcunlock(c
->privlock
);
990 const char *lxc_get_default_config_path(void)
992 return default_lxc_path();
995 struct lxc_container
*lxc_container_new(const char *name
, const char *configpath
)
997 struct lxc_container
*c
;
999 c
= malloc(sizeof(*c
));
1001 fprintf(stderr
, "failed to malloc lxc_container\n");
1004 memset(c
, 0, sizeof(*c
));
1007 c
->config_path
= strdup(configpath
);
1009 c
->config_path
= strdup(default_lxc_path());
1011 if (!c
->config_path
) {
1012 fprintf(stderr
, "Out of memory");
1016 c
->name
= malloc(strlen(name
)+1);
1018 fprintf(stderr
, "Error allocating lxc_container name\n");
1021 strcpy(c
->name
, name
);
1024 c
->slock
= lxc_newlock(name
);
1026 fprintf(stderr
, "failed to create lock\n");
1030 c
->privlock
= lxc_newlock(NULL
);
1032 fprintf(stderr
, "failed to alloc privlock\n");
1036 if (!set_config_filename(c
)) {
1037 fprintf(stderr
, "Error allocating config file pathname\n");
1041 if (file_exists(c
->configfile
))
1042 lxcapi_load_config(c
, NULL
);
1044 // assign the member functions
1045 c
->is_defined
= lxcapi_is_defined
;
1046 c
->state
= lxcapi_state
;
1047 c
->is_running
= lxcapi_is_running
;
1048 c
->freeze
= lxcapi_freeze
;
1049 c
->unfreeze
= lxcapi_unfreeze
;
1050 c
->init_pid
= lxcapi_init_pid
;
1051 c
->load_config
= lxcapi_load_config
;
1052 c
->want_daemonize
= lxcapi_want_daemonize
;
1053 c
->start
= lxcapi_start
;
1054 c
->startl
= lxcapi_startl
;
1055 c
->stop
= lxcapi_stop
;
1056 c
->config_file_name
= lxcapi_config_file_name
;
1057 c
->wait
= lxcapi_wait
;
1058 c
->set_config_item
= lxcapi_set_config_item
;
1059 c
->destroy
= lxcapi_destroy
;
1060 c
->save_config
= lxcapi_save_config
;
1061 c
->get_keys
= lxcapi_get_keys
;
1062 c
->create
= lxcapi_create
;
1063 c
->createl
= lxcapi_createl
;
1064 c
->shutdown
= lxcapi_shutdown
;
1065 c
->clear_config_item
= lxcapi_clear_config_item
;
1066 c
->get_config_item
= lxcapi_get_config_item
;
1067 c
->get_cgroup_item
= lxcapi_get_cgroup_item
;
1068 c
->set_cgroup_item
= lxcapi_set_cgroup_item
;
1069 c
->get_config_path
= lxcapi_get_config_path
;
1070 c
->set_config_path
= lxcapi_set_config_path
;
1072 /* we'll allow the caller to update these later */
1073 if (lxc_log_init(NULL
, "none", NULL
, "lxc_container", 0)) {
1074 fprintf(stderr
, "failed to open log\n");
1081 lxc_container_free(c
);
1085 int lxc_get_wait_states(const char **states
)
1090 for (i
=0; i
<MAX_STATE
; i
++)
1091 states
[i
] = lxc_state2str(i
);