[PATCH v2 1/2] kvm tools: Add support for 9p2000.u

[PATCH v2 1/2] kvm tools: Add support for 9p2000.u

[Sasha Levin]

This patch adds support for the UNIX extensions to 9p2000.

Supporting thses extensions allow us to transperantly mount UNIX directories
without missing features such as symlinks.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/include/kvm/virtio-9p.h |    4 +-
 tools/kvm/virtio/9p-pdu.c         |    6 ++-
 tools/kvm/virtio/9p.c             |   66 ++++++++++++++++++++++++++++++------
 3 files changed, 61 insertions(+), 15 deletions(-)

diff --git a/tools/kvm/include/kvm/virtio-9p.h b/tools/kvm/include/kvm/virtio-9p.h
index 8584f49..0e55e5c 100644
--- a/tools/kvm/include/kvm/virtio-9p.h
+++ b/tools/kvm/include/kvm/virtio-9p.h
@@ -11,8 +11,8 @@
 #define VIRTQUEUE_NUM		128
 #define	VIRTIO_P9_DEFAULT_TAG	"kvm_9p"
 #define VIRTIO_P9_HDR_LEN	(sizeof(u32)+sizeof(u8)+sizeof(u16))
-#define VIRTIO_P9_MAX_FID	128
-#define VIRTIO_P9_VERSION	"9P2000"
+#define VIRTIO_P9_MAX_FID	256
+#define VIRTIO_P9_VERSION	"9P2000.u"
 #define MAX_TAG_LEN		32
 
 struct p9_msg {
diff --git a/tools/kvm/virtio/9p-pdu.c b/tools/kvm/virtio/9p-pdu.c
index 0c454db..8ed249f 100644
--- a/tools/kvm/virtio/9p-pdu.c
+++ b/tools/kvm/virtio/9p-pdu.c
@@ -200,13 +200,15 @@ static int virtio_p9_pdu_encode(struct p9_pdu *pdu, const char *fmt, va_list ap)
 		case 'S':
 		{
 			struct p9_wstat *stbuf = va_arg(ap, struct p9_wstat *);
-			retval = virtio_p9_pdu_writef(pdu, "wwdQdddqssss",
+			retval = virtio_p9_pdu_writef(pdu, "wwdQdddqsssssddd",
 						stbuf->size, stbuf->type,
 						stbuf->dev, &stbuf->qid,
 						stbuf->mode, stbuf->atime,
 						stbuf->mtime, stbuf->length,
 						stbuf->name, stbuf->uid,
-						stbuf->gid, stbuf->muid);
+						stbuf->gid, stbuf->muid,
+						stbuf->extension, stbuf->n_uid,
+						stbuf->n_gid, stbuf->n_muid);
 		}
 		break;
 		default:
diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
index 3b5555c..965f873 100644
--- a/tools/kvm/virtio/9p.c
+++ b/tools/kvm/virtio/9p.c
@@ -162,7 +162,7 @@ static void virtio_p9_error_reply(struct p9_dev *p9dev,
 
 	err_str = strerror(err);
 	pdu->write_offset = VIRTIO_P9_HDR_LEN;
-	virtio_p9_pdu_writef(pdu, "s", err_str);
+	virtio_p9_pdu_writef(pdu, "sd", err_str, err);
 	*outlen = pdu->write_offset;
 
 	pdu->read_offset = sizeof(u32) + sizeof(u8);
@@ -204,7 +204,6 @@ static void virtio_p9_open(struct p9_dev *p9dev,
 	struct p9_qid qid;
 	struct p9_fid *new_fid;
 
-
 	virtio_p9_pdu_readf(pdu, "db", &fid, &mode);
 	new_fid = &p9dev->fids[fid];
 
@@ -242,13 +241,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
 	u8 mode;
 	u32 perm;
 	char *name;
+	char *ext = NULL;
 	u32 fid_val;
 	struct stat st;
 	struct p9_qid qid;
 	struct p9_fid *fid;
 	char full_path[PATH_MAX];
 
-	virtio_p9_pdu_readf(pdu, "dsdb", &fid_val, &name, &perm, &mode);
+	virtio_p9_pdu_readf(pdu, "dsdbs", &fid_val, &name, &perm, &mode, &ext);
 	fid = &p9dev->fids[fid_val];
 
 	sprintf(full_path, "%s/%s", fid->abs_path, name);
@@ -262,6 +262,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
 		close_fid(p9dev, fid_val);
 		fid->dir = dir;
 		fid->is_dir = 1;
+	} else if (perm & P9_DMSYMLINK) {
+		if (symlink(ext, full_path) < 0)
+			goto err_out;
+	} else if (perm & P9_DMLINK) {
+		int ext_fid = atoi(ext);
+
+		if (link(p9dev->fids[ext_fid].abs_path, full_path) < 0)
+			goto err_out;
 	} else {
 		fd = open(full_path, omode2uflags(mode) | O_CREAT, 0777);
 		if (fd < 0)
@@ -277,9 +285,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
 	virtio_p9_pdu_writef(pdu, "Qd", &qid, 0);
 	*outlen = pdu->write_offset;
 	virtio_p9_set_reply_header(pdu, *outlen);
+
+	free(name);
+	free(ext);
 	return;
 err_out:
 	virtio_p9_error_reply(p9dev, pdu, errno, outlen);
+	free(name);
+	free(ext);
 	return;
 }
 
@@ -294,7 +307,7 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
 	u32 newfid_val;
 	struct p9_qid wqid;
 	struct p9_fid *new_fid;
-
+	int ret;
 
 	virtio_p9_pdu_readf(pdu, "ddw", &fid_val, &newfid_val, &nwname);
 	new_fid	= &p9dev->fids[newfid_val];
@@ -315,7 +328,9 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
 			/* Format the new path we're 'walk'ing into */
 			sprintf(tmp, "%s/%.*s",
 				fid->path, (int)strlen(str), str);
-			if (lstat(rel_to_abs(p9dev, tmp, full_path), &st) < 0)
+
+			ret = lstat(rel_to_abs(p9dev, tmp, full_path), &st);
+			if (ret < 0)
 				goto err_out;
 
 			st2qid(&st, &wqid);
@@ -375,12 +390,22 @@ static void virtio_p9_attach(struct p9_dev *p9dev,
 	virtio_p9_pdu_writef(pdu, "Q", &qid);
 	*outlen = pdu->write_offset;
 	virtio_p9_set_reply_header(pdu, *outlen);
+	free(uname);
+	free(aname);
 	return;
 err_out:
+	free(uname);
+	free(aname);
 	virtio_p9_error_reply(p9dev, pdu, errno, outlen);
 	return;
 }
 
+static void virtio_p9_free_stat(struct p9_wstat *wstat)
+{
+	free(wstat->extension);
+	free(wstat->name);
+}
+
 static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
 				struct stat *st, struct p9_wstat *wstat)
 {
@@ -393,6 +418,17 @@ static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
 		wstat->length = 0;
 		wstat->mode |= P9_DMDIR;
 	}
+	if (S_ISLNK(st->st_mode)) {
+		char tmp[PATH_MAX] = {0}, full_path[PATH_MAX] = {0};
+
+		rel_to_abs(p9dev, name, full_path);
+
+		if (readlink(full_path, tmp, PATH_MAX) > 0)
+			wstat->extension = strdup(tmp);
+		wstat->mode |= P9_DMSYMLINK;
+	} else {
+		wstat->extension = NULL;
+	}
 
 	wstat->atime = st->st_atime;
 	wstat->mtime = st->st_mtime;
@@ -401,14 +437,20 @@ static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
 	wstat->uid = NULL;
 	wstat->gid = NULL;
 	wstat->muid = NULL;
+	wstat->n_uid = wstat->n_gid = wstat->n_muid = 0;
 
-	/* NOTE: size shouldn't include its own length */
-	/* size[2] type[2] dev[4] qid[13] */
-	/* mode[4] atime[4] mtime[4] length[8]*/
-	/* name[s] uid[s] gid[s] muid[s] */
-	wstat->size = 2+4+13+4+4+4+8+2+2+2+2;
+	/*
+	 * NOTE: size shouldn't include its own length
+	 * size[2] type[2] dev[4] qid[13]
+	 * mode[4] atime[4] mtime[4] length[8]
+	 * name[s] uid[s] gid[s] muid[s]
+	 * ext[s] uid[4] gid[4] muid[4]
+	 */
+	wstat->size = 2+4+13+4+4+4+8+2+2+2+2+2+4+4+4;
 	if (wstat->name)
 		wstat->size += strlen(wstat->name);
+	if (wstat->extension)
+		wstat->size += strlen(wstat->extension);
 }
 
 static void virtio_p9_read(struct p9_dev *p9dev,
@@ -440,6 +482,7 @@ static void virtio_p9_read(struct p9_dev *p9dev,
 			read = pdu->write_offset;
 			virtio_p9_pdu_writef(pdu, "S", &wstat);
 			rcount += pdu->write_offset - read;
+			virtio_p9_free_stat(&wstat);
 
 			cur = readdir(fid->dir);
 		}
@@ -486,6 +529,7 @@ static void virtio_p9_stat(struct p9_dev *p9dev,
 
 	virtio_p9_pdu_writef(pdu, "wS", 0, &wstat);
 	*outlen = pdu->write_offset;
+	virtio_p9_free_stat(&wstat);
 	virtio_p9_set_reply_header(pdu, *outlen);
 	return;
 err_out:
-- 
1.7.6

[PATCH v2 2/2] kvm tools: Add '--rootfs' and '--binsh'

[Sasha Levin]

This patch adds 2 new flags:

 --rootfs [path] - Specifies a path to use as rootfs. The path will be mounted
using virtio-9p and booted from.
Easiest way to test it is to mount the sample image we recommend with kvm tool
(http://wiki.qemu.org/download/linux-0.2.img.bz2) and mounting it somewhere.
*PLEASE DO NOT TRY BOOTING FROM YOUR REAL ROOT AKA '/', EVEN WITH READ ONLY
SET* - Lets make sure the code is bulletproof before we delete your rootfs :)

 --binsh - This flag will boot into simple /bin/sh shell instead of going
through /sbin/init. This is usefull for more complex distribution rootfs
where we have to deal with /etc/fstab and such.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
 tools/kvm/builtin-run.c |   18 +++++++++++++++++-
 1 files changed, 17 insertions(+), 1 deletions(-)

diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
index 2e04265..78680ec 100644
--- a/tools/kvm/builtin-run.c
+++ b/tools/kvm/builtin-run.c
@@ -76,11 +76,13 @@ static const char *guest_mac;
 static const char *host_mac;
 static const char *script;
 static const char *guest_name;
+static const char *rootfs;
 static bool single_step;
 static bool readonly_image[MAX_DISK_IMAGES];
 static bool vnc;
 static bool sdl;
 static bool balloon;
+static bool bin_sh;
 extern bool ioport_debug;
 extern int  active_console;
 extern int  debug_iodelay;
@@ -156,6 +158,8 @@ static const struct option options[] = {
 	OPT_BOOLEAN('\0', "balloon", &balloon, "Enable virtio balloon"),
 	OPT_BOOLEAN('\0', "vnc", &vnc, "Enable VNC framebuffer"),
 	OPT_BOOLEAN('\0', "sdl", &sdl, "Enable SDL framebuffer"),
+	OPT_STRING('\0', "rootfs", &rootfs, "path", "Use path as rootfs"),
+	OPT_BOOLEAN('\0', "binsh", &bin_sh, "Boot rootfs to /bin/sh instead of /sbin/init"),
 
 	OPT_GROUP("Kernel options:"),
 	OPT_STRING('k', "kernel", &kernel_filename, "kernel",
@@ -615,7 +619,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 		strlcat(real_cmdline, kernel_cmdline, sizeof(real_cmdline));
 
 	hi = NULL;
-	if (!image_filename[0]) {
+	if (!rootfs && !image_filename[0]) {
 		hi = host_image(real_cmdline, sizeof(real_cmdline));
 		if (hi) {
 			image_filename[0] = hi;
@@ -627,6 +631,18 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
 	if (!strstr(real_cmdline, "root="))
 		strlcat(real_cmdline, " root=/dev/vda rw ", sizeof(real_cmdline));
 
+	if (rootfs) {
+		char tmp[PATH_MAX];
+
+		if (realpath(rootfs, tmp) == 0 ||
+		    virtio_9p__init(kvm, tmp, "/dev/root") < 0)
+			die("Unable to initialize virtio 9p");
+		strcat(real_cmdline, " root=/dev/root rootflags=rw,trans=virtio,version=9p2000.u rootfstype=9p");
+
+		if (bin_sh)
+			strcat(real_cmdline, " init=/bin/sh");
+	}
+
 	if (image_count) {
 		kvm->nr_disks = image_count;
 		kvm->disks    = disk_image__open_all(image_filename, readonly_image, image_count);
-- 
1.7.6

Re: [PATCH v2 2/2] kvm tools: Add '--rootfs' and '--binsh'

[Aneesh Kumar K.V]

On Tue,  2 Aug 2011 21:46:29 +0300, Sasha Levin <levinsasha928@gmail.com> wrote:
> This patch adds 2 new flags:
> 
>  --rootfs [path] - Specifies a path to use as rootfs. The path will be mounted
> using virtio-9p and booted from.
> Easiest way to test it is to mount the sample image we recommend with kvm tool
> (http://wiki.qemu.org/download/linux-0.2.img.bz2) and mounting it somewhere.
> *PLEASE DO NOT TRY BOOTING FROM YOUR REAL ROOT AKA '/', EVEN WITH READ ONLY
> SET* - Lets make sure the code is bulletproof before we delete your rootfs :)
> 
>  --binsh - This flag will boot into simple /bin/sh shell instead of going
> through /sbin/init. This is usefull for more complex distribution rootfs
> where we have to deal with /etc/fstab and such.
> 
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

> ---
>  tools/kvm/builtin-run.c |   18 +++++++++++++++++-
>  1 files changed, 17 insertions(+), 1 deletions(-)
> 
> diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
> index 2e04265..78680ec 100644
> --- a/tools/kvm/builtin-run.c
> +++ b/tools/kvm/builtin-run.c
> @@ -76,11 +76,13 @@ static const char *guest_mac;
>  static const char *host_mac;
>  static const char *script;
>  static const char *guest_name;
> +static const char *rootfs;
>  static bool single_step;
>  static bool readonly_image[MAX_DISK_IMAGES];
>  static bool vnc;
>  static bool sdl;
>  static bool balloon;
> +static bool bin_sh;
>  extern bool ioport_debug;
>  extern int  active_console;
>  extern int  debug_iodelay;
> @@ -156,6 +158,8 @@ static const struct option options[] = {
>  	OPT_BOOLEAN('\0', "balloon", &balloon, "Enable virtio balloon"),
>  	OPT_BOOLEAN('\0', "vnc", &vnc, "Enable VNC framebuffer"),
>  	OPT_BOOLEAN('\0', "sdl", &sdl, "Enable SDL framebuffer"),
> +	OPT_STRING('\0', "rootfs", &rootfs, "path", "Use path as rootfs"),
> +	OPT_BOOLEAN('\0', "binsh", &bin_sh, "Boot rootfs to /bin/sh instead of /sbin/init"),
> 
>  	OPT_GROUP("Kernel options:"),
>  	OPT_STRING('k', "kernel", &kernel_filename, "kernel",
> @@ -615,7 +619,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>  		strlcat(real_cmdline, kernel_cmdline, sizeof(real_cmdline));
> 
>  	hi = NULL;
> -	if (!image_filename[0]) {
> +	if (!rootfs && !image_filename[0]) {
>  		hi = host_image(real_cmdline, sizeof(real_cmdline));
>  		if (hi) {
>  			image_filename[0] = hi;
> @@ -627,6 +631,18 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>  	if (!strstr(real_cmdline, "root="))
>  		strlcat(real_cmdline, " root=/dev/vda rw ", sizeof(real_cmdline));
> 
> +	if (rootfs) {
> +		char tmp[PATH_MAX];
> +
> +		if (realpath(rootfs, tmp) == 0 ||
> +		    virtio_9p__init(kvm, tmp, "/dev/root") < 0)
> +			die("Unable to initialize virtio 9p");
> +		strcat(real_cmdline, " root=/dev/root rootflags=rw,trans=virtio,version=9p2000.u rootfstype=9p");
> +
> +		if (bin_sh)
> +			strcat(real_cmdline, " init=/bin/sh");
> +	}
> +
>  	if (image_count) {
>  		kvm->nr_disks = image_count;
>  		kvm->disks    = disk_image__open_all(image_filename, readonly_image, image_count);
> -- 
> 1.7.6
> 

Re: [PATCH v2 2/2] kvm tools: Add '--rootfs' and '--binsh'

[Pekka Enberg]

On 8/3/11 5:52 AM, Aneesh Kumar K.V wrote:
> On Tue,  2 Aug 2011 21:46:29 +0300, Sasha Levin<levinsasha928@gmail.com>  wrote:
>> This patch adds 2 new flags:
>>
>>   --rootfs [path] - Specifies a path to use as rootfs. The path will be mounted
>> using virtio-9p and booted from.
>> Easiest way to test it is to mount the sample image we recommend with kvm tool
>> (http://wiki.qemu.org/download/linux-0.2.img.bz2) and mounting it somewhere.
>> *PLEASE DO NOT TRY BOOTING FROM YOUR REAL ROOT AKA '/', EVEN WITH READ ONLY
>> SET* - Lets make sure the code is bulletproof before we delete your rootfs :)
>>
>>   --binsh - This flag will boot into simple /bin/sh shell instead of going
>> through /sbin/init. This is usefull for more complex distribution rootfs
>> where we have to deal with /etc/fstab and such.
>>
>> Signed-off-by: Sasha Levin<levinsasha928@gmail.com>
> Reviewed-by: Aneesh Kumar K.V<aneesh.kumar@linux.vnet.ibm.com>
>
>> ---
>>   tools/kvm/builtin-run.c |   18 +++++++++++++++++-
>>   1 files changed, 17 insertions(+), 1 deletions(-)
>>
>> diff --git a/tools/kvm/builtin-run.c b/tools/kvm/builtin-run.c
>> index 2e04265..78680ec 100644
>> --- a/tools/kvm/builtin-run.c
>> +++ b/tools/kvm/builtin-run.c
>> @@ -76,11 +76,13 @@ static const char *guest_mac;
>>   static const char *host_mac;
>>   static const char *script;
>>   static const char *guest_name;
>> +static const char *rootfs;
>>   static bool single_step;
>>   static bool readonly_image[MAX_DISK_IMAGES];
>>   static bool vnc;
>>   static bool sdl;
>>   static bool balloon;
>> +static bool bin_sh;
>>   extern bool ioport_debug;
>>   extern int  active_console;
>>   extern int  debug_iodelay;
>> @@ -156,6 +158,8 @@ static const struct option options[] = {
>>   	OPT_BOOLEAN('\0', "balloon",&balloon, "Enable virtio balloon"),
>>   	OPT_BOOLEAN('\0', "vnc",&vnc, "Enable VNC framebuffer"),
>>   	OPT_BOOLEAN('\0', "sdl",&sdl, "Enable SDL framebuffer"),
>> +	OPT_STRING('\0', "rootfs",&rootfs, "path", "Use path as rootfs"),
>> +	OPT_BOOLEAN('\0', "binsh",&bin_sh, "Boot rootfs to /bin/sh instead of /sbin/init"),
>>
>>   	OPT_GROUP("Kernel options:"),
>>   	OPT_STRING('k', "kernel",&kernel_filename, "kernel",
>> @@ -615,7 +619,7 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>>   		strlcat(real_cmdline, kernel_cmdline, sizeof(real_cmdline));
>>
>>   	hi = NULL;
>> -	if (!image_filename[0]) {
>> +	if (!rootfs&&  !image_filename[0]) {
>>   		hi = host_image(real_cmdline, sizeof(real_cmdline));
>>   		if (hi) {
>>   			image_filename[0] = hi;
>> @@ -627,6 +631,18 @@ int kvm_cmd_run(int argc, const char **argv, const char *prefix)
>>   	if (!strstr(real_cmdline, "root="))
>>   		strlcat(real_cmdline, " root=/dev/vda rw ", sizeof(real_cmdline));
>>
>> +	if (rootfs) {
>> +		char tmp[PATH_MAX];
>> +
>> +		if (realpath(rootfs, tmp) == 0 ||
>> +		    virtio_9p__init(kvm, tmp, "/dev/root")<  0)
>> +			die("Unable to initialize virtio 9p");
>> +		strcat(real_cmdline, " root=/dev/root rootflags=rw,trans=virtio,version=9p2000.u rootfstype=9p");
>> +
>> +		if (bin_sh)
>> +			strcat(real_cmdline, " init=/bin/sh");
>> +	}
>>

Why don't we use the "-d" command line option for this? We can
use fstat() and S_ISDIR to detect that the user specified a directory
as a disk image?

I'm also not completely convinced we should introduce the 'binsh'
command line option. Instead, I'd simply default to 'init=/bin/sh'
unless the user uses -p to specify init.

                         Pekka

Re: [PATCH v2 2/2] kvm tools: Add '--rootfs' and '--binsh'

[Asias He]

On 08/03/2011 02:46 AM, Sasha Levin wrote:
> This patch adds 2 new flags:
> 
>  --rootfs [path] - Specifies a path to use as rootfs. The path will be mounted
> using virtio-9p and booted from.
> Easiest way to test it is to mount the sample image we recommend with kvm tool
> (http://wiki.qemu.org/download/linux-0.2.img.bz2) and mounting it somewhere.
> *PLEASE DO NOT TRY BOOTING FROM YOUR REAL ROOT AKA '/', EVEN WITH READ ONLY
> SET* - Lets make sure the code is bulletproof before we delete your rootfs :)
> 
>  --binsh - This flag will boot into simple /bin/sh shell instead of going
> through /sbin/init. This is usefull for more complex distribution rootfs
> where we have to deal with /etc/fstab and such.
> 
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

This is damn impressive!

All I needed is:

./kvm run -k /home/asias/qemu-stuff/bzImage --rootfs /mnt/


I found that if I boot with

./kvm run -k /home/asias/qemu-stuff/bzImage --rootfs /mnt/

I will get:

sh-2.05b# echo a > /root/a
sh: /root/a: No such file or directory

If I boot with

sudo ./kvm run -k /home/asias/qemu-stuff/bzImage --rootfs /mnt/

sh-2.05b# echo a > /root/a

works.

It seems that it is a permission related problem, however, the warning
message is "/root/a: No such file or directory", any ideas?

-- 
Best Regards,
Asias He

Re: [PATCH v2 1/2] kvm tools: Add support for 9p2000.u

[Aneesh Kumar K.V]

On Tue,  2 Aug 2011 21:46:28 +0300, Sasha Levin <levinsasha928@gmail.com> wrote:
> This patch adds support for the UNIX extensions to 9p2000.
> 
> Supporting thses extensions allow us to transperantly mount UNIX directories
> without missing features such as symlinks.
> 
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

> ---
>  tools/kvm/include/kvm/virtio-9p.h |    4 +-
>  tools/kvm/virtio/9p-pdu.c         |    6 ++-
>  tools/kvm/virtio/9p.c             |   66 ++++++++++++++++++++++++++++++------
>  3 files changed, 61 insertions(+), 15 deletions(-)
> 
> diff --git a/tools/kvm/include/kvm/virtio-9p.h b/tools/kvm/include/kvm/virtio-9p.h
> index 8584f49..0e55e5c 100644
> --- a/tools/kvm/include/kvm/virtio-9p.h
> +++ b/tools/kvm/include/kvm/virtio-9p.h
> @@ -11,8 +11,8 @@
>  #define VIRTQUEUE_NUM		128
>  #define	VIRTIO_P9_DEFAULT_TAG	"kvm_9p"
>  #define VIRTIO_P9_HDR_LEN	(sizeof(u32)+sizeof(u8)+sizeof(u16))
> -#define VIRTIO_P9_MAX_FID	128
> -#define VIRTIO_P9_VERSION	"9P2000"
> +#define VIRTIO_P9_MAX_FID	256
> +#define VIRTIO_P9_VERSION	"9P2000.u"
>  #define MAX_TAG_LEN		32
> 
>  struct p9_msg {
> diff --git a/tools/kvm/virtio/9p-pdu.c b/tools/kvm/virtio/9p-pdu.c
> index 0c454db..8ed249f 100644
> --- a/tools/kvm/virtio/9p-pdu.c
> +++ b/tools/kvm/virtio/9p-pdu.c
> @@ -200,13 +200,15 @@ static int virtio_p9_pdu_encode(struct p9_pdu *pdu, const char *fmt, va_list ap)
>  		case 'S':
>  		{
>  			struct p9_wstat *stbuf = va_arg(ap, struct p9_wstat *);
> -			retval = virtio_p9_pdu_writef(pdu, "wwdQdddqssss",
> +			retval = virtio_p9_pdu_writef(pdu, "wwdQdddqsssssddd",
>  						stbuf->size, stbuf->type,
>  						stbuf->dev, &stbuf->qid,
>  						stbuf->mode, stbuf->atime,
>  						stbuf->mtime, stbuf->length,
>  						stbuf->name, stbuf->uid,
> -						stbuf->gid, stbuf->muid);
> +						stbuf->gid, stbuf->muid,
> +						stbuf->extension, stbuf->n_uid,
> +						stbuf->n_gid, stbuf->n_muid);
>  		}
>  		break;
>  		default:
> diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
> index 3b5555c..965f873 100644
> --- a/tools/kvm/virtio/9p.c
> +++ b/tools/kvm/virtio/9p.c
> @@ -162,7 +162,7 @@ static void virtio_p9_error_reply(struct p9_dev *p9dev,
> 
>  	err_str = strerror(err);
>  	pdu->write_offset = VIRTIO_P9_HDR_LEN;
> -	virtio_p9_pdu_writef(pdu, "s", err_str);
> +	virtio_p9_pdu_writef(pdu, "sd", err_str, err);
>  	*outlen = pdu->write_offset;
> 
>  	pdu->read_offset = sizeof(u32) + sizeof(u8);
> @@ -204,7 +204,6 @@ static void virtio_p9_open(struct p9_dev *p9dev,
>  	struct p9_qid qid;
>  	struct p9_fid *new_fid;
> 
> -
>  	virtio_p9_pdu_readf(pdu, "db", &fid, &mode);
>  	new_fid = &p9dev->fids[fid];
> 
> @@ -242,13 +241,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
>  	u8 mode;
>  	u32 perm;
>  	char *name;
> +	char *ext = NULL;
>  	u32 fid_val;
>  	struct stat st;
>  	struct p9_qid qid;
>  	struct p9_fid *fid;
>  	char full_path[PATH_MAX];
> 
> -	virtio_p9_pdu_readf(pdu, "dsdb", &fid_val, &name, &perm, &mode);
> +	virtio_p9_pdu_readf(pdu, "dsdbs", &fid_val, &name, &perm, &mode, &ext);
>  	fid = &p9dev->fids[fid_val];
> 
>  	sprintf(full_path, "%s/%s", fid->abs_path, name);
> @@ -262,6 +262,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
>  		close_fid(p9dev, fid_val);
>  		fid->dir = dir;
>  		fid->is_dir = 1;
> +	} else if (perm & P9_DMSYMLINK) {
> +		if (symlink(ext, full_path) < 0)
> +			goto err_out;
> +	} else if (perm & P9_DMLINK) {
> +		int ext_fid = atoi(ext);
> +
> +		if (link(p9dev->fids[ext_fid].abs_path, full_path) < 0)
> +			goto err_out;
>  	} else {
>  		fd = open(full_path, omode2uflags(mode) | O_CREAT, 0777);
>  		if (fd < 0)
> @@ -277,9 +285,14 @@ static void virtio_p9_create(struct p9_dev *p9dev,
>  	virtio_p9_pdu_writef(pdu, "Qd", &qid, 0);
>  	*outlen = pdu->write_offset;
>  	virtio_p9_set_reply_header(pdu, *outlen);
> +
> +	free(name);
> +	free(ext);
>  	return;
>  err_out:
>  	virtio_p9_error_reply(p9dev, pdu, errno, outlen);
> +	free(name);
> +	free(ext);
>  	return;
>  }
> 
> @@ -294,7 +307,7 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
>  	u32 newfid_val;
>  	struct p9_qid wqid;
>  	struct p9_fid *new_fid;
> -
> +	int ret;
> 
>  	virtio_p9_pdu_readf(pdu, "ddw", &fid_val, &newfid_val, &nwname);
>  	new_fid	= &p9dev->fids[newfid_val];
> @@ -315,7 +328,9 @@ static void virtio_p9_walk(struct p9_dev *p9dev,
>  			/* Format the new path we're 'walk'ing into */
>  			sprintf(tmp, "%s/%.*s",
>  				fid->path, (int)strlen(str), str);
> -			if (lstat(rel_to_abs(p9dev, tmp, full_path), &st) < 0)
> +
> +			ret = lstat(rel_to_abs(p9dev, tmp, full_path), &st);
> +			if (ret < 0)
>  				goto err_out;
> 
>  			st2qid(&st, &wqid);
> @@ -375,12 +390,22 @@ static void virtio_p9_attach(struct p9_dev *p9dev,
>  	virtio_p9_pdu_writef(pdu, "Q", &qid);
>  	*outlen = pdu->write_offset;
>  	virtio_p9_set_reply_header(pdu, *outlen);
> +	free(uname);
> +	free(aname);
>  	return;
>  err_out:
> +	free(uname);
> +	free(aname);
>  	virtio_p9_error_reply(p9dev, pdu, errno, outlen);
>  	return;
>  }
> 
> +static void virtio_p9_free_stat(struct p9_wstat *wstat)
> +{
> +	free(wstat->extension);
> +	free(wstat->name);
> +}
> +
>  static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
>  				struct stat *st, struct p9_wstat *wstat)
>  {
> @@ -393,6 +418,17 @@ static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
>  		wstat->length = 0;
>  		wstat->mode |= P9_DMDIR;
>  	}
> +	if (S_ISLNK(st->st_mode)) {
> +		char tmp[PATH_MAX] = {0}, full_path[PATH_MAX] = {0};
> +
> +		rel_to_abs(p9dev, name, full_path);
> +
> +		if (readlink(full_path, tmp, PATH_MAX) > 0)
> +			wstat->extension = strdup(tmp);
> +		wstat->mode |= P9_DMSYMLINK;
> +	} else {
> +		wstat->extension = NULL;
> +	}
> 
>  	wstat->atime = st->st_atime;
>  	wstat->mtime = st->st_mtime;
> @@ -401,14 +437,20 @@ static void virtio_p9_fill_stat(struct p9_dev *p9dev, const char *name,
>  	wstat->uid = NULL;
>  	wstat->gid = NULL;
>  	wstat->muid = NULL;
> +	wstat->n_uid = wstat->n_gid = wstat->n_muid = 0;
> 
> -	/* NOTE: size shouldn't include its own length */
> -	/* size[2] type[2] dev[4] qid[13] */
> -	/* mode[4] atime[4] mtime[4] length[8]*/
> -	/* name[s] uid[s] gid[s] muid[s] */
> -	wstat->size = 2+4+13+4+4+4+8+2+2+2+2;
> +	/*
> +	 * NOTE: size shouldn't include its own length
> +	 * size[2] type[2] dev[4] qid[13]
> +	 * mode[4] atime[4] mtime[4] length[8]
> +	 * name[s] uid[s] gid[s] muid[s]
> +	 * ext[s] uid[4] gid[4] muid[4]
> +	 */
> +	wstat->size = 2+4+13+4+4+4+8+2+2+2+2+2+4+4+4;
>  	if (wstat->name)
>  		wstat->size += strlen(wstat->name);
> +	if (wstat->extension)
> +		wstat->size += strlen(wstat->extension);
>  }
> 
>  static void virtio_p9_read(struct p9_dev *p9dev,
> @@ -440,6 +482,7 @@ static void virtio_p9_read(struct p9_dev *p9dev,
>  			read = pdu->write_offset;
>  			virtio_p9_pdu_writef(pdu, "S", &wstat);
>  			rcount += pdu->write_offset - read;
> +			virtio_p9_free_stat(&wstat);
> 
>  			cur = readdir(fid->dir);
>  		}
> @@ -486,6 +529,7 @@ static void virtio_p9_stat(struct p9_dev *p9dev,
> 
>  	virtio_p9_pdu_writef(pdu, "wS", 0, &wstat);
>  	*outlen = pdu->write_offset;
> +	virtio_p9_free_stat(&wstat);
>  	virtio_p9_set_reply_header(pdu, *outlen);
>  	return;
>  err_out:
> -- 
> 1.7.6
>