[lxc-devel] [Patch] Resubmit: MAKEDEV call, add autodev hooks, add environment variables for hook scripts.

Michael H. Warfield mhw at WittsEnd.com
Mon Jan 14 16:59:36 UTC 2013


Ok...  Here's the patch again.  Since Serge is removing the loglevel
structure member, this patch no longer references that element.

Signed-off-by: Michael H. Warfield <mhw at WittsEnd.com>

Regards,
Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
   /\/\|=mhw=|\/\/          | (678) 463-0932 |  http://www.wittsend.com/mhw/
   NIC whois: MHW9          | An optimist believes we live in the best of all
 PGP Key: 0x674627FF        | possible worlds.  A pessimist is sure of it!

-- 

diff --git a/doc/lxc.conf.sgml.in b/doc/lxc.conf.sgml.in
index 96dea89..1298143 100644
--- a/doc/lxc.conf.sgml.in
+++ b/doc/lxc.conf.sgml.in
@@ -510,6 +510,10 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 	rootfs.  If lxc.autodev is set to 1, then after mounting the container's
 	rootfs LXC will mount a fresh tmpfs under <filename>/dev</filename>
 	(limited to 100k) and fill in a minimal set of initial devices.
+        This is generally required when starting a container containing
+        a "systemd" based "init" but may be optional at other times.  Addional
+        devices in the containers /dev directory may be created through the
+        use of the <option>lxc.hook.autodev</option> hook.
       </para>
       <variablelist>
 	<varlistentry>
@@ -737,6 +741,27 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       <variablelist>
 	<varlistentry>
 	  <term>
+	    <option>lxc.hook.autodev</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      A hook to be run in the container's namespace after
+	      mounting has been done and after any mount hooks have
+	      run, but before the pivot_root, if
+	      <option>lxc.autodev</option> == 1.
+	      The purpose of this hook is to assist in populating the
+	      /dev directory of the container when using the autodev
+	      option for systemd based containers.  The container's /dev
+	      directory is relative to the
+	      ${<option>LXC_ROOTFS_MOUNT</option>} environment
+	      variable available when the hook is run.
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
 	    <option>lxc.hook.start</option>
 	  </term>
 	  <listitem>
@@ -763,6 +788,103 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
       </variablelist>
     </refsect2>
 
+    <refsect2>
+      <title>Startup hooks Environment Variables</title>
+      <para>
+        A number of environment variables are made available to the startup
+        hooks to provide configuration information and assist in the
+        functioning of the hooks.  Not all variables are valid in all
+        contexts.  In particular, all paths are relative to the host system
+        and, as such, not valid during the <option>lxc.hook.start</option> hook.
+      </para>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_NAME</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      The LXC name of the container.  Useful for logging messages
+	      in commmon log environments.  [<option>-n</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_CONFIG_FILE</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      Host relative path to the container configuration file.  This
+	      gives the container to reference the original, top level,
+	      configuration file for the container in order to locate any
+	      addotional configuration information not otherwise made
+	      available.  [<option>-f</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_CONSOLE</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      The path to the console output of the container if not NULL.
+	      [<option>-c</option>] [<option>lxc.console</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_CONSOLE_LOGPATH</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      The path to the console log output of the container if not NULL.
+	      [<option>-L</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_ROOTFS_MOUNT</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      The mount location to which the container is initially bound.
+	      This will be the host relative path to the container rootfs
+	      for the container instance being started and is where changes
+	      should be made for that instance.
+	      [<option>lxc.rootfs.mount</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+      <variablelist>
+	<varlistentry>
+	  <term>
+	    <option>LXC_ROOTFS_PATH</option>
+	  </term>
+	  <listitem>
+	    <para>
+	      The host relative path to the container root which has been
+	      mounted to the rootfs.mount location.
+	      [<option>lxc.rootfs</option>]
+	    </para>
+	  </listitem>
+	</varlistentry>
+      </variablelist>
+
+    </refsect2>
+
   </refsect1>
 
   <refsect1>
diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 1c02850..699011a 100644
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -116,7 +116,7 @@ lxc_log_define(lxc_conf, lxc);
 #endif
 
 char *lxchook_names[NUM_LXC_HOOKS] = {
-	"pre-start", "pre-mount", "mount", "start", "post-stop" };
+	"pre-start", "pre-mount", "mount", "autodev", "start", "post-stop" };
 
 extern int pivot_root(const char * new_root, const char * put_old);
 
@@ -913,33 +913,6 @@ static int mount_autodev(char *root)
 	return 0;
 }
 
-/*
- * Try to run MAKEDEV console in the container.  If something fails,
- * continue anyway as it should not be detrimental to the container.
- * This makes sure that things like /dev/vcs* exist.
- * (Pass devpath in to reduce stack usage)
- */
-static void run_makedev(char *devpath)
-{
-	int curd;
-	int ret;
-
-	curd = open(".", O_RDONLY);
-	if (curd < 0)
-		return;
-	ret = chdir(devpath);
-	if (ret) {
-		close(curd);
-		return;
-	}
-	if (run_buffer("/sbin/MAKEDEV console"))
-		INFO("Error running MAKEDEV console in %s", devpath);
-	ret = fchdir(curd);
-	if (ret)
-		INFO("Error returning to original directory: expect breakage");
-	close(curd);
-}
-
 struct lxc_devs {
 	char *name;
 	mode_t mode;
@@ -971,8 +944,7 @@ static int setup_autodev(char *root)
 	if (ret < 0 || ret >= MAXPATHLEN) {
 		ERROR("Error calculating container /dev location");
 		return -1;
-	} else
-		run_makedev(path);
+	}
 
 	INFO("Populating /dev under %s\n", root);
 	cmask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
@@ -2553,6 +2525,10 @@ int lxc_setup(const char *name, struct lxc_conf *lxc_conf)
 	}
 
 	if (lxc_conf->autodev) {
+		if (run_lxc_hooks(name, "autodev", lxc_conf)) {
+			ERROR("failed to run autodev hooks for container '%s'.", name);
+			return -1;
+		}
 		if (setup_autodev(lxc_conf->rootfs.mount)) {
 			ERROR("failed to populate /dev in the container");
 			return -1;
@@ -2628,6 +2604,8 @@ int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf)
 		which = LXCHOOK_PREMOUNT;
 	else if (strcmp(hook, "mount") == 0)
 		which = LXCHOOK_MOUNT;
+	else if (strcmp(hook, "autodev") == 0)
+		which = LXCHOOK_AUTODEV;
 	else if (strcmp(hook, "start") == 0)
 		which = LXCHOOK_START;
 	else if (strcmp(hook, "post-stop") == 0)
diff --git a/src/lxc/conf.h b/src/lxc/conf.h
index b576893..45161e1 100644
--- a/src/lxc/conf.h
+++ b/src/lxc/conf.h
@@ -213,8 +213,8 @@ struct lxc_rootfs {
 #endif
  */
 enum lxchooks {
-	LXCHOOK_PRESTART, LXCHOOK_PREMOUNT, LXCHOOK_MOUNT, LXCHOOK_START,
-	LXCHOOK_POSTSTOP, NUM_LXC_HOOKS};
+	LXCHOOK_PRESTART, LXCHOOK_PREMOUNT, LXCHOOK_MOUNT, LXCHOOK_AUTODEV,
+	LXCHOOK_START, LXCHOOK_POSTSTOP, NUM_LXC_HOOKS};
 extern char *lxchook_names[NUM_LXC_HOOKS];
 
 struct saved_nic {
@@ -257,6 +257,7 @@ struct lxc_conf {
 #endif
 	int maincmd_fd;
 	int autodev;  // if 1, mount and fill a /dev at start
+	char *rcfile;	// Copy of the top level rcfile we read
 };
 
 int run_lxc_hooks(const char *name, char *hook, struct lxc_conf *conf);
diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 1d87227..8cef8be 100644
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -104,6 +104,7 @@ static struct lxc_config_t config[] = {
 	{ "lxc.hook.pre-start",       config_hook                 },
 	{ "lxc.hook.pre-mount",       config_hook                 },
 	{ "lxc.hook.mount",           config_hook                 },
+	{ "lxc.hook.autodev",         config_hook                 },
 	{ "lxc.hook.start",           config_hook                 },
 	{ "lxc.hook.post-stop",       config_hook                 },
 	{ "lxc.network.type",         config_network_type         },
@@ -821,6 +822,8 @@ static int config_hook(const char *key, const char *value,
 		return add_hook(lxc_conf, LXCHOOK_PRESTART, copy);
 	else if (strcmp(key, "lxc.hook.pre-mount") == 0)
 		return add_hook(lxc_conf, LXCHOOK_PREMOUNT, copy);
+	else if (strcmp(key, "lxc.hook.autodev") == 0)
+		return add_hook(lxc_conf, LXCHOOK_AUTODEV, copy);
 	else if (strcmp(key, "lxc.hook.mount") == 0)
 		return add_hook(lxc_conf, LXCHOOK_MOUNT, copy);
 	else if (strcmp(key, "lxc.hook.start") == 0)
@@ -1265,6 +1268,10 @@ int lxc_config_readline(char *buffer, struct lxc_conf *conf)
 
 int lxc_config_read(const char *file, struct lxc_conf *conf)
 {
+	/* Catch only the top level config file name in the structure */
+	if( ! conf->rcfile ) {
+		conf->rcfile = strdup( file );
+	}
 	return lxc_file_for_each_line(file, parse_line, conf);
 }
 
diff --git a/src/lxc/lxc_start.c b/src/lxc/lxc_start.c
index 184fb04..a97dcca 100644
--- a/src/lxc/lxc_start.c
+++ b/src/lxc/lxc_start.c
@@ -168,15 +168,6 @@ int main(int argc, char *argv[])
 			 my_args.progname, my_args.quiet))
 		return err;
 
-	if (clearenv()) {
-		SYSERROR("failed to clear environment");
-		/* don't error out though */
-	}
-	if (putenv("container=lxc")) {
-		SYSERROR("failed to set environment variable");
-		return err;
-	}
-
 	/* rcfile is specified in the cli option */
 	if (my_args.rcfile)
 		rcfile = (char *)my_args.rcfile;
diff --git a/src/lxc/start.c b/src/lxc/start.c
index 82a74d8..e5b3638 100644
--- a/src/lxc/start.c
+++ b/src/lxc/start.c
@@ -391,6 +391,27 @@ struct lxc_handler *lxc_init(const char *name, struct lxc_conf *conf)
 		goto out_free_name;
 	}
 
+	/* Start of environment variable setup for hooks */
+	if (setenv("LXC_NAME", name, 1)) {
+		SYSERROR("failed to set environment variable for container name");
+	}
+	if (setenv("LXC_CONFIG_FILE", conf->rcfile, 1)) {
+		SYSERROR("failed to set environment variable for config path");
+	}
+	if (setenv("LXC_ROOTFS_MOUNT", conf->rootfs.mount, 1)) {
+		SYSERROR("failed to set environment variable for rootfs mount");
+	}
+	if (setenv("LXC_ROOTFS_PATH", conf->rootfs.path, 1)) {
+		SYSERROR("failed to set environment variable for rootfs mount");
+	}
+	if (conf->console.path && setenv("LXC_CONSOLE", conf->console.path, 1)) {
+		SYSERROR("failed to set environment variable for console path");
+	}
+	if (conf->console.log_path && setenv("LXC_CONSOLE_LOGPATH", conf->console.log_path, 1)) {
+		SYSERROR("failed to set environment variable for console log");
+	}
+	/* End of environment variable setup for hooks */
+
 	if (run_lxc_hooks(name, "pre-start", conf)) {
 		ERROR("failed to run pre-start hooks for container '%s'.", name);
 		goto out_aborting;
@@ -575,6 +596,21 @@ static int do_start(void *data)
 		goto out_warn_father;
 	}
 
+	/* The clearenv() and putenv() calls have been moved here
+	 * to allow us to use enviroment variables passed to the various
+	 * hooks, such as the start hook above.  Not all of the
+	 * variables like CONFIG_PATH or ROOTFS are valid in this
+	 * context but others are. */
+	if (clearenv()) {
+		SYSERROR("failed to clear environment");
+		/* don't error out though */
+	}
+
+	if (putenv("container=lxc")) {
+		SYSERROR("failed to set environment variable");
+		return -1;
+	}
+
 	close(handler->sigfd);
 
 	/* after this call, we are in error because this

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