From: hallyn <serge@hallyn.com>
Date: Mon, 25 Nov 2013 21:55:30 +0000 (-0800)
Subject: Merge pull request #92 from majek/share-namespaces
X-Git-Tag: lxc-1.0.0.beta1~93
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7faa7f52004943f339199bcbad1848cdf50d5f4c;p=thirdparty%2Flxc.git

Merge pull request #92 from majek/share-namespaces

Add options to `lxc-start` to inherit network, ipc and uts namespaces
---

7faa7f52004943f339199bcbad1848cdf50d5f4c
diff --cc src/lxc/conf.c
index 860fc5b63,dfc49e435..534e6e6fb
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@@ -3377,93 -3139,13 +3380,95 @@@ int ttys_shift_ids(struct lxc_conf *c
  	return 0;
  }
  
 -int lxc_setup(const char *name, struct lxc_conf *lxc_conf, const char *lxcpath, struct cgroup_process_info *cgroup_info)
 +/*
 + * This routine is called when the configuration does not already specify a value
 + * for autodev (mounting a file system on /dev and populating it in a container).
 + * If a hard override value has not be specified, then we try to apply some
 + * heuristics to determine if we should switch to autodev mode.
 + *
 + * For instance, if the container has an /etc/systemd/system directory then it
 + * is probably running systemd as the init process and it needs the autodev
 + * mount to prevent it from mounting devtmpfs on /dev on it's own causing conflicts
 + * in the host.
 + *
 + * We may also want to enable autodev if the host has devtmpfs mounted on its
 + * /dev as this then enable us to use subdirectories under /dev for the container
 + * /dev directories and we can fake udev devices.
 + */
 +struct start_args {
 +	char *const *argv;
 +};
 +
 +#define MAX_SYMLINK_DEPTH 32
 +
 +int check_autodev( const char *rootfs, void *data )
 +{
 +	struct start_args *arg = data;
 +	int ret;
 +	int loop_count = 0;
 +	struct stat s;
 +	char absrootfs[MAXPATHLEN];
 +	char path[MAXPATHLEN];
 +	char abs_path[MAXPATHLEN];
 +	char *command = "/sbin/init";
 +
 +	if (rootfs == NULL || strlen(rootfs) == 0)
 +		return -2;
 +
 +	if (!realpath(rootfs, absrootfs))
 +		return -2;
 +
 +	if( arg && arg->argv[0] ) {
 +		command = arg->argv[0];
 +		DEBUG("Set exec command to %s\n", command );
 +	}
 +
 +	strncpy( path, command, MAXPATHLEN-1 );
 +
 +	if ( 0 != access(path, F_OK) || 0 != stat(path, &s) )
 +		return -2;
 +
 +	/* Dereference down the symlink merry path testing as we go. */
 +	/* If anything references systemd in the path - set autodev! */
 +	/* Renormalize to the rootfs before each dereference */
 +	/* Relative symlinks should fall out in the wash even with .. */
 +	while( 1 ) {
 +		if ( strstr( path, "systemd" ) ) {
 +			INFO("Container with systemd init detected - enabling autodev!");
 +			return 1;
 +		}
 +
 +		ret = snprintf(abs_path, MAXPATHLEN-1, "%s/%s", absrootfs, path);
 +		if (ret < 0 || ret > MAXPATHLEN)
 +			return -2;
 +
 +		ret = readlink( abs_path, path, MAXPATHLEN-1 );
 +
 +		if ( ( ret <= 0 ) || ( ++loop_count > MAX_SYMLINK_DEPTH ) ) {
 +			break; /* Break out for other tests */
 +		}
 +		path[ret] = '\0';
 +	}
 +
 +	/*
 +	 * Add future checks here.
 +	 *	Return positive if we should go autodev
 +	 *	Return 0 if we should NOT go autodev
 +	 *	Return negative if we encounter an error or can not determine...
 +	 */
 +
 +	/* All else fails, we don't need autodev */
 +	INFO("Autodev not required.");
 +	return 0;
 +}
 +
 +int lxc_setup(const char *name, struct lxc_conf *lxc_conf, const char *lxcpath, struct cgroup_process_info *cgroup_info, void *data)
  {
- 	if (setup_utsname(lxc_conf->utsname)) {
- 		ERROR("failed to setup the utsname for '%s'", name);
- 		return -1;
+ 	if (lxc_conf->inherit_ns_fd[LXC_NS_UTS] == -1) {
+ 		if (setup_utsname(lxc_conf->utsname)) {
+ 			ERROR("failed to setup the utsname for '%s'", name);
+ 			return -1;
+ 		}
  	}
  
  	if (setup_network(&lxc_conf->network)) {