[Qemu-devel] [PULL 0/3] 9pfs fixes for 2.11 20170920

[Qemu-devel] [PULL 0/3] 9pfs fixes for 2.11 20170920

[Greg Kurz]

The following changes since commit c51700273ad9802a21c19f8d2b4bcb67c38e74ac:

  Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20170919-v2' into staging (2017-09-19 18:08:48 +0100)

are available in the git repository at:

  https://github.com/gkurz/qemu.git tags/for-upstream

for you to fetch changes up to 772a73692ecb52bace0cff6f95df62f59b8cabe0:

  9pfs: check the size of transport buffer before marshaling (2017-09-20 08:48:52 +0200)

----------------------------------------------------------------
These patches fix regressions in 2.10

----------------------------------------------------------------
Jan Dakinevich (3):
      9pfs: fix readdir() for 9p2000.u
      9pfs: fix name_to_path assertion in v9fs_complete_rename()
      9pfs: check the size of transport buffer before marshaling

 hw/9pfs/9p.c | 60 ++++++++++++++++++++++++++++++------------------------------
 1 file changed, 30 insertions(+), 30 deletions(-)
-- 
2.13.5

[Qemu-devel] [PULL 1/3] 9pfs: fix readdir() for 9p2000.u

[Greg Kurz]

From: Jan Dakinevich <jan.dakinevich@gmail.com>

If the client is using 9p2000.u, the following occurs:

$ cd ${virtfs_shared_dir}
$ mkdir -p a/b/c
$ ls a/b
ls: cannot access 'a/b/a': No such file or directory
ls: cannot access 'a/b/b': No such file or directory
a  b  c

instead of the expected:

$ ls a/b
c

This is a regression introduced by commit f57f5878578a;
local_name_to_path() now resolves ".." and "." in paths,
and v9fs_do_readdir_with_stat()->stat_to_v9stat() then
copies the basename of the resulting path to the response.
With the example above, this means that "." and ".." are
turned into "b" and "a" respectively...

stat_to_v9stat() currently assumes it is passed a full
canonicalized path and uses it to do two different things:
1) to pass it to v9fs_co_readlink() in case the file is a symbolic
   link
2) to set the name field of the V9fsStat structure to the basename
   part of the given path

It only has two users: v9fs_stat() and v9fs_do_readdir_with_stat().

v9fs_stat() really needs 1) and 2) to be performed since it starts
with the full canonicalized path stored in the fid. It is different
for v9fs_do_readdir_with_stat() though because the name we want to
put into the V9fsStat structure is the d_name field of the dirent
actually (ie, we want to keep the "." and ".." special names). So,
we only need 1) in this case.

This patch hence adds a basename argument to stat_to_v9stat(), to
be used to set the name field of the V9fsStat structure, and moves
the basename logic to v9fs_stat().

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
(groug, renamed old name argument to path and updated changelog)
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p.c | 22 +++++++++-------------
 1 file changed, 9 insertions(+), 13 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 0a37c8bd1361..1078cfdaa4af 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -803,12 +803,12 @@ static uint32_t stat_to_v9mode(const struct stat *stbuf)
     return mode;
 }
 
-static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *name,
+static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *path,
+                                       const char *basename,
                                        const struct stat *stbuf,
                                        V9fsStat *v9stat)
 {
     int err;
-    const char *str;
 
     memset(v9stat, 0, sizeof(*v9stat));
 
@@ -829,7 +829,7 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *name,
     v9fs_string_free(&v9stat->extension);
 
     if (v9stat->mode & P9_STAT_MODE_SYMLINK) {
-        err = v9fs_co_readlink(pdu, name, &v9stat->extension);
+        err = v9fs_co_readlink(pdu, path, &v9stat->extension);
         if (err < 0) {
             return err;
         }
@@ -842,14 +842,7 @@ static int coroutine_fn stat_to_v9stat(V9fsPDU *pdu, V9fsPath *name,
                 "HARDLINKCOUNT", (unsigned long)stbuf->st_nlink);
     }
 
-    str = strrchr(name->data, '/');
-    if (str) {
-        str += 1;
-    } else {
-        str = name->data;
-    }
-
-    v9fs_string_sprintf(&v9stat->name, "%s", str);
+    v9fs_string_sprintf(&v9stat->name, "%s", basename);
 
     v9stat->size = 61 +
         v9fs_string_size(&v9stat->name) +
@@ -1056,6 +1049,7 @@ static void coroutine_fn v9fs_stat(void *opaque)
     struct stat stbuf;
     V9fsFidState *fidp;
     V9fsPDU *pdu = opaque;
+    char *basename;
 
     err = pdu_unmarshal(pdu, offset, "d", &fid);
     if (err < 0) {
@@ -1072,7 +1066,9 @@ static void coroutine_fn v9fs_stat(void *opaque)
     if (err < 0) {
         goto out;
     }
-    err = stat_to_v9stat(pdu, &fidp->path, &stbuf, &v9stat);
+    basename = g_path_get_basename(fidp->path.data);
+    err = stat_to_v9stat(pdu, &fidp->path, basename, &stbuf, &v9stat);
+    g_free(basename);
     if (err < 0) {
         goto out;
     }
@@ -1748,7 +1744,7 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
         if (err < 0) {
             break;
         }
-        err = stat_to_v9stat(pdu, &path, &stbuf, &v9stat);
+        err = stat_to_v9stat(pdu, &path, dent->d_name, &stbuf, &v9stat);
         if (err < 0) {
             break;
         }
-- 
2.13.5

[Qemu-devel] [PULL 2/3] 9pfs: fix name_to_path assertion in v9fs_complete_rename()

[Greg Kurz]

From: Jan Dakinevich <jan.dakinevich@gmail.com>

The third parameter of v9fs_co_name_to_path() must not contain `/'
character.

The issue is most likely related to 9p2000.u protocol only.

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
[groug, regression caused by commit f57f5878578a # 2.10]
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p.c | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 1078cfdaa4af..cdd44bdc82ef 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -2553,13 +2553,11 @@ static int coroutine_fn v9fs_complete_rename(V9fsPDU *pdu, V9fsFidState *fidp,
                                              int32_t newdirfid,
                                              V9fsString *name)
 {
-    char *end;
     int err = 0;
     V9fsPath new_path;
     V9fsFidState *tfidp;
     V9fsState *s = pdu->s;
     V9fsFidState *dirfidp = NULL;
-    char *old_name, *new_name;
 
     v9fs_path_init(&new_path);
     if (newdirfid != -1) {
@@ -2577,18 +2575,15 @@ static int coroutine_fn v9fs_complete_rename(V9fsPDU *pdu, V9fsFidState *fidp,
             goto out;
         }
     } else {
-        old_name = fidp->path.data;
-        end = strrchr(old_name, '/');
-        if (end) {
-            end++;
-        } else {
-            end = old_name;
-        }
-        new_name = g_malloc0(end - old_name + name->size + 1);
-        strncat(new_name, old_name, end - old_name);
-        strncat(new_name + (end - old_name), name->data, name->size);
-        err = v9fs_co_name_to_path(pdu, NULL, new_name, &new_path);
-        g_free(new_name);
+        char *dir_name = g_path_get_dirname(fidp->path.data);
+        V9fsPath dir_path;
+
+        v9fs_path_init(&dir_path);
+        v9fs_path_sprintf(&dir_path, "%s", dir_name);
+        g_free(dir_name);
+
+        err = v9fs_co_name_to_path(pdu, &dir_path, name->data, &new_path);
+        v9fs_path_free(&dir_path);
         if (err < 0) {
             goto out;
         }
-- 
2.13.5

[Qemu-devel] [PULL 3/3] 9pfs: check the size of transport buffer before marshaling

[Greg Kurz]

From: Jan Dakinevich <jan.dakinevich@gmail.com>

v9fs_do_readdir_with_stat() should check for a maximum buffer size
before an attempt to marshal gathered data. Otherwise, buffers assumed
as misconfigured and the transport would be broken.

The patch brings v9fs_do_readdir_with_stat() in conformity with
v9fs_do_readdir() behavior.

Signed-off-by: Jan Dakinevich <jan.dakinevich@gmail.com>
[groug, regression caused my commit 8d37de41cab1 # 2.10]
Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index cdd44bdc82ef..23ac7bb532f0 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1748,17 +1748,26 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
         if (err < 0) {
             break;
         }
+        if ((count + v9stat.size + 2) > max_count) {
+            v9fs_readdir_unlock(&fidp->fs.dir);
+
+            /* Ran out of buffer. Set dir back to old position and return */
+            v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
+            v9fs_stat_free(&v9stat);
+            v9fs_path_free(&path);
+            return count;
+        }
+
         /* 11 = 7 + 4 (7 = start offset, 4 = space for storing count) */
         len = pdu_marshal(pdu, 11 + count, "S", &v9stat);
 
         v9fs_readdir_unlock(&fidp->fs.dir);
 
-        if ((len != (v9stat.size + 2)) || ((count + len) > max_count)) {
-            /* Ran out of buffer. Set dir back to old position and return */
+        if (len < 0) {
             v9fs_co_seekdir(pdu, fidp, saved_dir_pos);
             v9fs_stat_free(&v9stat);
             v9fs_path_free(&path);
-            return count;
+            return len;
         }
         count += len;
         v9fs_stat_free(&v9stat);
-- 
2.13.5

Re: [Qemu-devel] [PULL 0/3] 9pfs fixes for 2.11 20170920

[Peter Maydell]

On 20 September 2017 at 14:50, Greg Kurz <groug@kaod.org> wrote:
> The following changes since commit c51700273ad9802a21c19f8d2b4bcb67c38e74ac:
>
>   Merge remote-tracking branch 'remotes/cohuck/tags/s390x-20170919-v2' into staging (2017-09-19 18:08:48 +0100)
>
> are available in the git repository at:
>
>   https://github.com/gkurz/qemu.git tags/for-upstream
>
> for you to fetch changes up to 772a73692ecb52bace0cff6f95df62f59b8cabe0:
>
>   9pfs: check the size of transport buffer before marshaling (2017-09-20 08:48:52 +0200)
>
> ----------------------------------------------------------------
> These patches fix regressions in 2.10
>
> ----------------------------------------------------------------
> Jan Dakinevich (3):
>       9pfs: fix readdir() for 9p2000.u
>       9pfs: fix name_to_path assertion in v9fs_complete_rename()
>       9pfs: check the size of transport buffer before marshaling
>
>  hw/9pfs/9p.c | 60 ++++++++++++++++++++++++++++++------------------------------
>  1 file changed, 30 insertions(+), 30 deletions(-)
> --
> 2.13.5

Applied, thanks.

-- PMM