added dynamic interface manipulation for guests

management of tap devices on the host

1 files changed, 108 insertions, 15 deletions

diff --git a/src/dumm/guest.c b/src/dumm/guest.c
index 202882367..cdb97c7bd 100644
--- a/src/dumm/guest.c
+++ b/src/dumm/guest.c
@@ -1,3 +1,18 @@
+/*
+ * Copyright (C) 2007 Martin Willi
+ * Hochschule fuer Technik Rapperswil
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
 #define _GNU_SOURCE
 
 #include <sys/types.h>
@@ -10,27 +25,88 @@
 #include <signal.h>
 
 #include <debug.h>
+#include <utils/linked_list.h>
 
 #include "dumm.h"
 #include "guest.h"
+#include "mconsole.h"
 
 typedef struct private_guest_t private_guest_t;
 
 struct private_guest_t {
+	/** implemented public interface */
 	guest_t public;
+	/** name of the guest */
 	char *name;
+	/** kernel to boot for guest */
 	char *kernel;
+	/** read only master filesystem guest uses */
 	char *master;
+	/** amount of memory for guest, in MB */
 	int mem;
+	/** pid of guest child process */
 	int pid;
+	/** log file for console 0 */
 	int bootlog;
+	/** mconsole to control running UML */
+	mconsole_t *mconsole;
+	/** list of interfaces attached to the guest */
+	linked_list_t *ifaces;
 };
 
+/**
+ * Implementation of guest_t.get_name.
+ */
 static char* get_name(private_guest_t *this)
 {
 	return this->name;
 }
 
+/**
+ * Implementation of guest_t.create_iface.
+ */
+static iface_t* create_iface(private_guest_t *this, char *name)
+{
+	iterator_t *iterator;
+	iface_t *iface;
+	
+	if (this->pid == 0)
+	{
+		DBG1("guest '%s' not running, unable to add interface", this->name);
+		return NULL;
+	}
+	
+	iterator = this->ifaces->create_iterator(this->ifaces, TRUE);
+	while (iterator->iterate(iterator, (void**)&iface))
+	{
+		if (streq(name, iface->get_guest(iface)))
+		{
+			DBG1("guest '%s' already has an interface '%s'", this->name, name);
+			iterator->destroy(iterator);
+			return NULL;
+		}
+	}
+	iterator->destroy(iterator);
+
+	iface = iface_create(name, this->mconsole);
+	if (iface)
+	{
+		this->ifaces->insert_last(this->ifaces, iface);
+	}
+	return iface;
+}
+
+/**
+ * Implementation of guest_t.create_iface_iterator.
+ */
+static iterator_t* create_iface_iterator(private_guest_t *this)
+{
+	return this->ifaces->create_iterator(this->ifaces, TRUE);
+}
+
+/**
+ * write format string to a buffer, and advance buffer position
+ */
 static char* write_arg(char **pos, size_t *left, char *format, ...)
 {
 	size_t len;
@@ -50,6 +126,9 @@ static char* write_arg(char **pos, size_t *left, char *format, ...)
 	return res;
 }
 
+/**
+ * Implementation of guest_t.start.
+ */
 static bool start(private_guest_t *this)
 {
 	char buf[1024];
@@ -67,7 +146,7 @@ static bool start(private_guest_t *this)
 	args[i++] = write_arg(&pos, &left, "uml_dir=%s/%s", RUN_DIR, this->name);
 	args[i++] = write_arg(&pos, &left, "umid=%s", this->name);
 	args[i++] = write_arg(&pos, &left, "mem=%dM", this->mem);
-	//args[i++] = write_arg(&pos, &left, "con=pts");
+	/*args[i++] = write_arg(&pos, &left, "con=pts");*/
 	args[i++] = write_arg(&pos, &left, "con0=null,fd:%d", this->bootlog);
 	args[i++] = write_arg(&pos, &left, "con1=fd:0,fd:1");
 	args[i++] = write_arg(&pos, &left, "con3=null,null");
@@ -84,15 +163,30 @@ static bool start(private_guest_t *this)
 			dup2(open("/dev/null", 0), 1);
 			dup2(open("/dev/null", 0), 2);
 			execvp(args[0], args);
+			DBG1("starting UML kernel '%s' failed", args[0]);
 			exit(1);
 		case -1:
 			this->pid = 0;
 			return FALSE;
 		default:
-			return TRUE;
+			break;
+	}
+	/* open mconsole */
+	snprintf(buf, sizeof(buf), "%s/%s/%s/mconsole", RUN_DIR, this->name, this->name);
+	this->mconsole = mconsole_create(buf);
+	if (this->mconsole == NULL)
+	{
+		DBG1("opening mconsole at '%s' failed, stopping guest", buf);
+		kill(this->pid, SIGINT);
+		this->pid = 0;
+		return FALSE;
 	}
+	return TRUE;
 }
 
+/**
+ * Implementation of guest_t.stop.
+ */
 static void stop(private_guest_t *this)
 {
 	if (this->pid)
@@ -103,7 +197,7 @@ static void stop(private_guest_t *this)
 }
 
 /**
- * create a directory
+ * Check if directory exists, create otherwise
  */
 static bool makedir(char *dir, char *name)
 {
@@ -138,6 +232,7 @@ static bool umount_unionfs(char *name)
 	}
 	if (system(cmd) != 0)
 	{
+		DBG1("unmounting guest unionfs for %s failed", name);
 		return FALSE;
 	}
 	return TRUE;
@@ -151,7 +246,6 @@ static bool mount_unionfs(char *name, char *master)
 	char cmd[256];
 	size_t len;
 	
-	/* mount unionfs */
 	len = snprintf(cmd, sizeof(cmd), "unionfs %s/%s:%s %s/%s",
 				   HOST_DIR, name, master, MOUNT_DIR, name);
 	if (len < 0 || len >= sizeof(cmd))
@@ -160,7 +254,7 @@ static bool mount_unionfs(char *name, char *master)
 	}
 	if (system(cmd) != 0)
 	{
-		DBG1("mounting unionfs using '%s' failed.", cmd);
+		DBG1("mounting guest unionfs for %s using '%s' failed", name, cmd);
 		return FALSE;
 	}
 	return TRUE;
@@ -183,18 +277,21 @@ static int open_bootlog(char *name)
 	fd = open(blg, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR);
 	if (fd == -1)
 	{
+		DBG1("opening bootlog '%s' for %s failed, using stdout", blg, name);
 		return 1;
 	}
 	return fd;
 }
 
 /**
- * stop guest, unmount mounts
+ * Implementation of guest_t.destroy.
  */
 static void destroy(private_guest_t *this)
 {
 	stop(this);
 	umount_unionfs(this->name);
+	this->ifaces->destroy_offset(this->ifaces, offsetof(iface_t, destroy));
+	DESTROY_IF(this->mconsole);
 	free(this->name);
 	free(this->kernel);
 	free(this->master);
@@ -209,21 +306,15 @@ guest_t *guest_create(char *name, char *kernel, char *master, int mem)
 	private_guest_t *this = malloc_thing(private_guest_t);
 	
 	this->public.get_name = (void*)get_name;
+	this->public.create_iface = (iface_t*(*)(guest_t*,char*))create_iface;
+	this->public.create_iface_iterator = (iterator_t*(*)(guest_t*))create_iface_iterator;
 	this->public.start = (void*)start;
 	this->public.stop = (void*)stop;
 	this->public.destroy = (void*)destroy;
 	
 	if (!makedir(HOST_DIR, name) || !makedir(MOUNT_DIR, name) ||
-		!makedir(RUN_DIR, name))
-	{
-		DBG1("creating guest directories for %s failed failed.", name);
-		free(this);
-		return NULL;
-	}
-	
-	if (!mount_unionfs(name, master))
+		!makedir(RUN_DIR, name) || !mount_unionfs(name, master))
 	{
-		DBG1("mounting guest unionfs for %s failed.", name);
 		free(this);
 		return NULL;
 	}
@@ -234,6 +325,8 @@ guest_t *guest_create(char *name, char *kernel, char *master, int mem)
 	this->mem = mem;
 	this->pid = 0;
 	this->bootlog = open_bootlog(name);
+	this->mconsole = NULL;
+	this->ifaces = linked_list_create();
 
 	return &this->public;
 }