[PATCH 1/2] kvm tools: Don't copy network autoconfiguration script

[PATCH 1/2] kvm tools: Don't copy network autoconfiguration script

[Sasha Levin]

Network autoconfiguration was moved to the kernel, but the setup code still
tried to copy the script over to the rootfs. This prevented from /virt/ to
be properly created.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/builtin-setup.c |   13 -------------
 1 files changed, 0 insertions(+), 13 deletions(-)

diff --git a/tools/kvm/builtin-setup.c b/tools/kvm/builtin-setup.c
index c93eec3..6b8eb5b 100644
--- a/tools/kvm/builtin-setup.c
+++ b/tools/kvm/builtin-setup.c
@@ -129,15 +129,6 @@ static int copy_init(const char *guestfs_name)
 	return copy_file("guest/init", path);
 }
 
-static int copy_net(const char *guestfs_name)
-{
-	char path[PATH_MAX];
-
-	snprintf(path, PATH_MAX, "%s%s%s/virt/setnet.sh", HOME_DIR, KVM_PID_FILE_PATH, guestfs_name);
-
-	return copy_file("guest/setnet.sh", path);
-}
-
 static int make_guestfs_symlink(const char *guestfs_name, const char *path)
 {
 	char target[PATH_MAX];
@@ -195,10 +186,6 @@ static int do_setup(const char *guestfs_name)
 		make_guestfs_symlink(guestfs_name, guestfs_symlinks[i]);
 	}
 
-	ret = copy_net(guestfs_name);
-	if (ret < 0)
-		return ret;
-
 	return copy_init(guestfs_name);
 }
 
-- 
1.7.6.1

[PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Sasha Levin]

Since kernel IP autoconfiguration doesn't set up /etc/resolv.conf, we'll
use the one located within the host, since this was anyway what we simulated
within the DHCP offer packets.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/builtin-run.c               |    2 ++
 tools/kvm/builtin-setup.c             |    9 +++++++++
 tools/kvm/include/kvm/builtin-setup.h |    1 +
 3 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index 5dafb15..9d61088 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -129,6 +129,7 @@ static int img_name_parser(const struct option *opt, const char *arg, int unset)
 			die("Unable to initialize virtio 9p");
 		if (virtio_9p__register(kvm, "/", "hostfs") < 0)
 			die("Unable to initialize virtio 9p");
+		kvm_setup_resolv(arg);
 		using_rootfs = custom_rootfs = 1;
 		return 0;
 	}
@@ -750,6 +751,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 		char tmp[PATH_MAX];
 
 		kvm_setup_create_new("default");
+		kvm_setup_resolv("default");
 
 		snprintf(tmp, PATH_MAX, "%s%s%s", HOME_DIR, KVM_PID_FILE_PATH, "default");
 		if (virtio_9p__register(kvm, tmp, "/dev/root") < 0)
diff --git a/tools/kvm/builtin-setup.c b/tools/kvm/builtin-setup.c
index 6b8eb5b..3e569e7 100644
--- a/tools/kvm/builtin-setup.c
+++ b/tools/kvm/builtin-setup.c
@@ -168,6 +168,15 @@ static void make_guestfs_dir(const char *guestfs_name, const char *dir)
 	make_dir(name);
 }
 
+void kvm_setup_resolv(const char *guestfs_name)
+{
+	char path[PATH_MAX];
+
+	snprintf(path, PATH_MAX, "%s%s%s/etc/resolv.conf", HOME_DIR, KVM_PID_FILE_PATH, guestfs_name);
+
+	copy_file("/etc/resolv.conf", path);
+}
+
 static int do_setup(const char *guestfs_name)
 {
 	unsigned int i;
diff --git a/tools/kvm/include/kvm/builtin-setup.h b/tools/kvm/include/kvm/builtin-setup.h
index 6e183a1..f70ae78 100644
--- a/tools/kvm/include/kvm/builtin-setup.h
+++ b/tools/kvm/include/kvm/builtin-setup.h
@@ -4,5 +4,6 @@
 int kvm_cmd_setup(int argc, const char **argv, const char *prefix);
 void kvm_setup_help(void);
 int kvm_setup_create_new(const char *guestfs_name);
+void kvm_setup_resolv(const char *guestfs_name);
 
 #endif
-- 
1.7.6.1

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Pekka Enberg]

On Wed, Sep 14, 2011 at 7:28 PM, Sasha Levin <levinsasha928@gmail.com> wrote:
> Since kernel IP autoconfiguration doesn't set up /etc/resolv.conf, we'll
> use the one located within the host, since this was anyway what we simulated
> within the DHCP offer packets.
>
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

Wouldn't a symlink to /host/etc/resolv.conf be more appropriate?
Remember, we're supposed to only need to setup the shared rootfs once.

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Sasha Levin]

On Thu, 2011-09-15 at 08:29 +0300, Pekka Enberg wrote:
> On Wed, Sep 14, 2011 at 7:28 PM, Sasha Levin <levinsasha928@gmail.com> wrote:
> > Since kernel IP autoconfiguration doesn't set up /etc/resolv.conf, we'll
> > use the one located within the host, since this was anyway what we simulated
> > within the DHCP offer packets.
> >
> > Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> 
> Wouldn't a symlink to /host/etc/resolv.conf be more appropriate?
> Remember, we're supposed to only need to setup the shared rootfs once.

It would mean the guest can screw up with the host's networking.

-- 

Sasha.

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Pekka Enberg]

On 9/15/11 8:36 AM, Sasha Levin wrote:
> On Thu, 2011-09-15 at 08:29 +0300, Pekka Enberg wrote:
>> On Wed, Sep 14, 2011 at 7:28 PM, Sasha Levin<levinsasha928@gmail.com>  wrote:
>>> Since kernel IP autoconfiguration doesn't set up /etc/resolv.conf, we'll
>>> use the one located within the host, since this was anyway what we simulated
>>> within the DHCP offer packets.
>>>
>>> Signed-off-by: Sasha Levin<levinsasha928@gmail.com>
>>
>> Wouldn't a symlink to /host/etc/resolv.conf be more appropriate?
>> Remember, we're supposed to only need to setup the shared rootfs once.
>
> It would mean the guest can screw up with the host's networking.

How? You're not supposed to run the tool.

			Pekka

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Sasha Levin]

On Thu, 2011-09-15 at 08:44 +0300, Pekka Enberg wrote:
> On 9/15/11 8:36 AM, Sasha Levin wrote:
> > On Thu, 2011-09-15 at 08:29 +0300, Pekka Enberg wrote:
> >> On Wed, Sep 14, 2011 at 7:28 PM, Sasha Levin<levinsasha928@gmail.com>  wrote:
> >>> Since kernel IP autoconfiguration doesn't set up /etc/resolv.conf, we'll
> >>> use the one located within the host, since this was anyway what we simulated
> >>> within the DHCP offer packets.
> >>>
> >>> Signed-off-by: Sasha Levin<levinsasha928@gmail.com>
> >>
> >> Wouldn't a symlink to /host/etc/resolv.conf be more appropriate?
> >> Remember, we're supposed to only need to setup the shared rootfs once.
> >
> > It would mean the guest can screw up with the host's networking.
> 
> How? You're not supposed to run the tool.

Hm? If you it to the host's resolv.conf, a guest can edit host's file,
no?

Might even be not on purpose... For example, simply running dhcpcd on
the guest.

-- 

Sasha.

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Pekka Enberg]

On Thu, Sep 15, 2011 at 9:00 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> Hm? If you it to the host's resolv.conf, a guest can edit host's file,
> no?
>
> Might even be not on purpose... For example, simply running dhcpcd on
> the guest.

How is that going to happen if you're not running kvmtool as root?

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Sasha Levin]

On Thu, 2011-09-15 at 09:04 +0300, Pekka Enberg wrote:
> On Thu, Sep 15, 2011 at 9:00 AM, Sasha Levin <levinsasha928@gmail.com> wrote:
> > Hm? If you it to the host's resolv.conf, a guest can edit host's file,
> > no?
> >
> > Might even be not on purpose... For example, simply running dhcpcd on
> > the guest.
> 
> How is that going to happen if you're not running kvmtool as root?

In that case, dhcpcd in the guest will simply break because it can't
modify resolv.conf, no?

-- 

Sasha.

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Pekka Enberg]

On 9/15/11 9:04 AM, Sasha Levin wrote:
> On Thu, 2011-09-15 at 09:04 +0300, Pekka Enberg wrote:
>> On Thu, Sep 15, 2011 at 9:00 AM, Sasha Levin<levinsasha928@gmail.com>  wrote:
>>> Hm? If you it to the host's resolv.conf, a guest can edit host's file,
>>> no?
>>>
>>> Might even be not on purpose... For example, simply running dhcpcd on
>>> the guest.
>>
>> How is that going to happen if you're not running kvmtool as root?
>
> In that case, dhcpcd in the guest will simply break because it can't
> modify resolv.conf, no?

Yes. Why is that a problem? You're not supposed to launch a dhcp client
when using shared rootfs because kvmtool takes care of that for you.

			Pekka

Re: [PATCH 2/2] kvm tools: Use host's resolv.conf within the guest

[Sasha Levin]

On Thu, 2011-09-15 at 09:22 +0300, Pekka Enberg wrote:
> On 9/15/11 9:04 AM, Sasha Levin wrote:
> > On Thu, 2011-09-15 at 09:04 +0300, Pekka Enberg wrote:
> >> On Thu, Sep 15, 2011 at 9:00 AM, Sasha Levin<levinsasha928@gmail.com>  wrote:
> >>> Hm? If you it to the host's resolv.conf, a guest can edit host's file,
> >>> no?
> >>>
> >>> Might even be not on purpose... For example, simply running dhcpcd on
> >>> the guest.
> >>
> >> How is that going to happen if you're not running kvmtool as root?
> >
> > In that case, dhcpcd in the guest will simply break because it can't
> > modify resolv.conf, no?
> 
> Yes. Why is that a problem? You're not supposed to launch a dhcp client
> when using shared rootfs because kvmtool takes care of that for you.

Why? Testing a brand new dhcp client for example :)

We can't block the user from editing guest configuration files...

-- 

Sasha.