Commit 0e35a378 authored by Greg Kurz's avatar Greg Kurz
Browse files

9pfs: local: keep a file descriptor on the shared folder 



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: default avatarGreg Kurz <groug@kaod.org>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 6482a961

hw/9pfs/9p-local.c

+28 −2
Original line number Diff line number Diff line
@@ -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



typedef struct {

    int mountfd;

} LocalData;



#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;

    LocalData *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 ioctl 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)

{

    LocalData *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,