diff mbox

[05/29] 9pfs: local: keep a file descriptor on the shared folder

Message ID 148760159920.31154.1371018412446175087.stgit@bahia.lan
State New
Headers show

Commit Message

Greg Kurz Feb. 20, 2017, 2:39 p.m. UTC 
This patch opens the shared folder and caches the file descriptor, so that
it can be used to do symlink-safe path walk.

Signed-off-by: Greg Kurz <groug@kaod.org>
---
 hw/9pfs/9p-local.c |   30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

Comments

Stefan Hajnoczi Feb. 23, 2017, 11:23 a.m. UTC | #1 
On Mon, Feb 20, 2017 at 03:39:59PM +0100, Greg Kurz wrote:
> This patch opens the shared folder and caches the file descriptor, so that
> it can be used to do symlink-safe path walk.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
>  hw/9pfs/9p-local.c |   30 ++++++++++++++++++++++++++++--
>  1 file changed, 28 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
> index c2239bfafce4..8aee7f2516ed 100644
> --- a/hw/9pfs/9p-local.c
> +++ b/hw/9pfs/9p-local.c
> @@ -14,6 +14,7 @@
>  #include "qemu/osdep.h"
>  #include "9p.h"
>  #include "9p-xattr.h"
> +#include "9p-util.h"
>  #include "fsdev/qemu-fsdev.h"   /* local_ops */
>  #include <arpa/inet.h>
>  #include <pwd.h>
> @@ -43,6 +44,10 @@
>  #define BTRFS_SUPER_MAGIC 0x9123683E
>  #endif
>  
> +struct local_data {

QEMU coding style would requires:

  typedef struct {
      int mountfd;
  } LocalData;

Otherwise:

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
diff mbox

Patch

diff --git a/hw/9pfs/9p-local.c b/hw/9pfs/9p-local.c
index c2239bfafce4..8aee7f2516ed 100644
--- a/hw/9pfs/9p-local.c
+++ b/hw/9pfs/9p-local.c
@@ -14,6 +14,7 @@ 
 #include "qemu/osdep.h"
 #include "9p.h"
 #include "9p-xattr.h"
+#include "9p-util.h"
 #include "fsdev/qemu-fsdev.h"   /* local_ops */
 #include <arpa/inet.h>
 #include <pwd.h>
@@ -43,6 +44,10 @@ 
 #define BTRFS_SUPER_MAGIC 0x9123683E
 #endif
 
+struct local_data {
+    int mountfd;
+};
+
 #define VIRTFS_META_DIR ".virtfs_metadata"
 
 static char *local_mapped_attr_path(FsContext *ctx, const char *path)
@@ -1176,13 +1181,20 @@  static int local_ioc_getversion(FsContext *ctx, V9fsPath *path,
 static int local_init(FsContext *ctx)
 {
     struct statfs stbuf;
+    struct local_data *data = g_malloc(sizeof(*data));
+
+    data->mountfd = open(ctx->fs_root, O_DIRECTORY | O_RDONLY);
+    if (data->mountfd == -1) {
+        goto err;
+    }
 
 #ifdef FS_IOC_GETVERSION
     /*
      * use ioc_getversion only if the iocl is definied
      */
-    if (statfs(ctx->fs_root, &stbuf) < 0) {
-        return -1;
+    if (fstatfs(data->mountfd, &stbuf) < 0) {
+        close_preserve_errno(data->mountfd);
+        goto err;
     }
     switch (stbuf.f_type) {
     case EXT2_SUPER_MAGIC:
@@ -1209,7 +1221,20 @@  static int local_init(FsContext *ctx)
     }
     ctx->export_flags |= V9FS_PATHNAME_FSCONTEXT;
 
+    ctx->private = data;
     return 0;
+
+err:
+    g_free(data);
+    return -1;
+}
+
+static void local_cleanup(FsContext *ctx)
+{
+    struct local_data *data = ctx->private;
+
+    close(data->mountfd);
+    g_free(data);
 }
 
 static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
@@ -1252,6 +1277,7 @@  static int local_parse_opts(QemuOpts *opts, struct FsDriverEntry *fse)
 FileOperations local_ops = {
     .parse_opts = local_parse_opts,
     .init  = local_init,
+    .cleanup = local_cleanup,
     .lstat = local_lstat,
     .readlink = local_readlink,
     .close = local_close,