api: convert lxc_start

Normal lxc-start usage tends to be "lxc-start -n name [-P lxcpath]".
This causes $lxcpath/$name/config to be the configuration for the
container.  However, lxc-start is more flexible than that.  You can
specify a custom configuration file, in which case $lxcpath/$name/config
is not used.  You can also (in addition or in place of either of these)
specify configuration entries one-by-one using "-s lxc.utsname=xxx".

To support this using the API, if we are not using
$lxcpath/$name/config then we put ourselves into a custom lxcpath
called (configurable using LXCPATH) /var/lib/lxc_anon.  To stop a
container so created, then, you would use

	lxc-stop -P /var/lib/lxc_anon -n name

TODO: we should walk over the list of &defines by hand and set them
using c->set_config_item.  I haven't done that in this patch.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>

diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index 3a1241032ad6115cf0a9085cdc17b179f84e1411..125284cd24fe60282088812e52d672b7ca8da799 100644 (file)
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -43,6 +43,7 @@
 #include "log.h"
 #include "caps.h"
 #include "lxc.h"
+#include "lxccontainer.h"
 #include "conf.h"
 #include "cgroup.h"
 #include "utils.h"
@@ -151,6 +152,8 @@ int main(int argc, char *argv[])
                '\0',
        };
        FILE *pid_fp = NULL;
+       struct lxc_container *c;
+       char *anonpath;
 
        lxc_list_init(&defines);
 
@@ -169,13 +172,32 @@ int main(int argc, char *argv[])
                         my_args.progname, my_args.quiet, my_args.lxcpath[0]))
                return err;
 
+       anonpath = alloca(strlen(LXCPATH) + 6);
+       sprintf(anonpath, "%s_anon", LXCPATH);
+       /*
+        * rcfile possibilities:
+        * 1. rcfile from random path specified in cli option
+        * 2. rcfile not specified, use $lxcpath/$lxcname/config
+        * 3. rcfile not specified and does not exist.
+        */
        /* rcfile is specified in the cli option */
-       if (my_args.rcfile)
+       if (my_args.rcfile) {
                rcfile = (char *)my_args.rcfile;
-       else {
+               c = lxc_container_new(my_args.name, anonpath);
+               if (!c) {
+                       ERROR("Failed to create lxc_container");
+                       return err;
+               }
+               if (!c->load_config(c, rcfile)) {
+                       ERROR("Failed to load rcfile");
+                       lxc_container_put(c);
+                       return err;
+               }
+       } else {
                int rc;
+               const char *lxcpath = my_args.lxcpath[0];
 
-               rc = asprintf(&rcfile, "%s/%s/config", my_args.lxcpath[0], my_args.name);
+               rc = asprintf(&rcfile, "%s/%s/config", lxcpath, my_args.name);
                if (rc == -1) {
                        SYSERROR("failed to allocate memory");
                        return err;
@@ -186,25 +208,28 @@ int main(int argc, char *argv[])
                if (access(rcfile, F_OK)) {
                        free(rcfile);
                        rcfile = NULL;
+                       lxcpath = anonpath;
+               }
+               c = lxc_container_new(my_args.name, lxcpath);
+               if (!c) {
+                       ERROR("Failed to create lxc_container");
+                       return err;
                }
        }
 
-       conf = lxc_conf_init();
-       if (!conf) {
-               ERROR("failed to initialize configuration");
-               return err;
-       }
-
-       if (rcfile && lxc_config_read(rcfile, conf)) {
-               ERROR("failed to read configuration file");
-               goto out;
-       }
+       /*
+        * We should use set_config_item() over &defines, which would handle
+        * unset c->lxc_conf for us and let us not use lxc_config_define_load()
+        */
+       if (!c->lxc_conf)
+               c->lxc_conf = lxc_conf_init();
+       conf = c->lxc_conf;
 
        if (lxc_config_define_load(&defines, conf))
                goto out;
 
        if (!rcfile && !strcmp("/sbin/init", args[0])) {
-               ERROR("no configuration file for '/sbin/init' (may crash the host)");
+               ERROR("Executing '/sbin/init' with no configuration file may crash the host");
                goto out;
        }
 
@@ -228,10 +253,7 @@ int main(int argc, char *argv[])
        }
 
        if (my_args.daemonize) {
-               if (daemon(0, 0)) {
-                       SYSERROR("failed to daemonize '%s'", my_args.name);
-                       goto out;
-               }
+               c->want_daemonize(c);
        }
 
        if (pid_fp != NULL) {
@@ -245,23 +267,13 @@ int main(int argc, char *argv[])
        if (my_args.close_all_fds)
                conf->close_all_fds = 1;
 
-       err = lxc_start(my_args.name, args, conf, my_args.lxcpath[0]);
-
-       /*
-        * exec ourself, that requires to have all opened fd
-        * with the close-on-exec flag set
-        */
-       if (conf->reboot) {
-               INFO("rebooting container");
-               execvp(argv[0], argv);
-               SYSERROR("failed to exec");
-               err = -1;
-       }
+       err = c->start(c, 0, args) ? 0 : -1;
 
        if (my_args.pidfile)
                unlink(my_args.pidfile);
+
 out:
-       lxc_conf_free(conf);
+       lxc_container_put(c);
        return err;
 }