[Qemu-devel] Re: [V9fs-developer] [PATCH] [virtio-9p] Server side implementation for TLINK

["Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>]

On Sun, 30 May 2010 09:40:38 -0700, "Venkateswararao Jujjuri (JV)" <jvrao@linux.vnet.ibm.com> wrote:
> Create a link.
> 
> SYNOPSIS
> 
> size[4] Tlink tag[2] dfid[4] oldpath[s] newpath[s]
> 
> size[4] Rlink tag[2]
> 
> DESCRIPTION
> 
> Create a link 'newpath' in directory pointed by dfid linking to oldpath.
> 
> Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
> ---
>  hw/file-op-9p.h      |    2 +-
>  hw/virtio-9p-debug.c |    9 +++++++++
>  hw/virtio-9p-local.c |    2 +-
>  hw/virtio-9p.c       |   40 ++++++++++++++++++++++++++++++++--------
>  hw/virtio-9p.h       |    2 ++
>  5 files changed, 45 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/file-op-9p.h b/hw/file-op-9p.h
> index b3a320c..6744d69 100644
> --- a/hw/file-op-9p.h
> +++ b/hw/file-op-9p.h
> @@ -55,7 +55,7 @@ typedef struct FileOperations
>      int (*utime)(FsContext *, const char *, const struct utimbuf *);
>      int (*remove)(FsContext *, const char *);
>      int (*symlink)(FsContext *, const char *, const char *, FsCred *);
> -    int (*link)(FsContext *, const char *, const char *, FsCred *);
> +    int (*link)(FsContext *, const char *, const char *);
>      int (*setuid)(FsContext *, uid_t);
>      int (*close)(FsContext *, int);
>      int (*closedir)(FsContext *, DIR *);
> diff --git a/hw/virtio-9p-debug.c b/hw/virtio-9p-debug.c
> index a82b771..a870b97 100644
> --- a/hw/virtio-9p-debug.c
> +++ b/hw/virtio-9p-debug.c
> @@ -463,6 +463,15 @@ void pprint_pdu(V9fsPDU *pdu)
>      case P9_RCLUNK:
>          fprintf(llogfile, "RCLUNK: (");
>          break;
> +    case P9_TLINK:
> +        fprintf(llogfile, "TLINK: (");
> +        pprint_int32(pdu, 0, &offset, "fid");
> +        pprint_str(pdu, 0, &offset, ", name");
> +        pprint_str(pdu, 0, &offset, ", linkname");
> +        break;
> +    case P9_RLINK:
> +        fprintf(llogfile, "RLINK: (");
> +        break;
>      case P9_TREMOVE:
>          fprintf(llogfile, "TREMOVE: (");
>          pprint_int32(pdu, 0, &offset, "fid");
> diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
> index c5678ae..fa8d05c 100644
> --- a/hw/virtio-9p-local.c
> +++ b/hw/virtio-9p-local.c
> @@ -375,7 +375,7 @@ err_end:
>  }
> 
>  static int local_link(FsContext *fs_ctx, const char *oldpath,
> -        const char *newpath, FsCred *credp)
> +        const char *newpath)
>  {
>      char *tmp = qemu_strdup(rpath(fs_ctx, oldpath));
>      int err;


I guess it would be good to make sure local_link use linkat with
flags = 0 to ensure that we won't follow symlinks. But that can be
seperate patch.



> diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
> index 097dce8..d36d206 100644
> --- a/hw/virtio-9p.c
> +++ b/hw/virtio-9p.c
> @@ -212,14 +212,9 @@ static int v9fs_do_symlink(V9fsState *s, V9fsCreateState *vs)
>              &cred);
>  }
> 
> -static int v9fs_do_link(V9fsState *s, V9fsFidState *nfidp, V9fsCreateState *vs)
> +static int v9fs_do_link(V9fsState *s, char *oldpath, char *fullname)
>  {
> -    FsCred cred;
> -    cred_init(&cred);
> -    cred.fc_uid = nfidp->uid;
> -    cred.fc_mode = vs->perm & 0777;
> -
> -    return s->ops->link(&s->ctx, nfidp->path.data, vs->fullname.data, &cred);
> +    return s->ops->link(&s->ctx, oldpath, fullname);
>  }
> 
>  static int v9fs_do_truncate(V9fsState *s, V9fsString *path, off_t size)
> @@ -1919,7 +1914,7 @@ static void v9fs_create_post_lstat(V9fsState *s, V9fsCreateState *vs, int err)
>              err = -errno;
>              v9fs_post_create(s, vs, err);
>          }
> -        err = v9fs_do_link(s, nfidp, vs);
> +        err = v9fs_do_link(s, nfidp->path.data, vs->fullname.data);
>          v9fs_create_post_perms(s, vs, err);
>      } else if (vs->perm & P9_STAT_MODE_DEVICE) {
>          char ctype;
> @@ -1999,6 +1994,34 @@ out:
>      qemu_free(vs);
>  }
> 
> +static void v9fs_link(V9fsState *s, V9fsPDU *pdu)
> +{
> +    int32_t dfid;
> +    V9fsFidState *dfidp;
> +    V9fsString name, fullname, oldname;
> +    size_t offset = 7;
> +    int err = 0;
> +
> +    v9fs_string_init(&fullname);
> +
> +    pdu_unmarshal(pdu, offset, "dss", &dfid, &oldname, &name);
> +
> +    dfidp = lookup_fid(s, dfid);
> +    if (dfidp == NULL) {
> +        err = -errno;
> +        goto out;
> +    }
> +
> +    v9fs_string_sprintf(&fullname, "%s/%s", dfidp->path.data, name.data);
> +    err = v9fs_do_link(s, oldname.data, fullname.data);
> +    v9fs_string_free(&fullname);
> +
> +out:
> +    v9fs_string_free(&name);
> +    v9fs_string_free(&oldname);
> +    complete_pdu(s, pdu, err);
> +}
> +
>  static void v9fs_flush(V9fsState *s, V9fsPDU *pdu)
>  {
>      /* A nop call with no return */
> @@ -2354,6 +2377,7 @@ static pdu_handler_t *pdu_handlers[] = {
>      [P9_TAUTH] = v9fs_auth,
>  #endif
>      [P9_TFLUSH] = v9fs_flush,
> +    [P9_TLINK] = v9fs_link,
>      [P9_TCREATE] = v9fs_create,
>      [P9_TWRITE] = v9fs_write,
>      [P9_TWSTAT] = v9fs_wstat,
> diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h
> index 9773659..6b3d4a4 100644
> --- a/hw/virtio-9p.h
> +++ b/hw/virtio-9p.h
> @@ -17,6 +17,8 @@ enum {
>      P9_RSTATFS,
>      P9_TREADDIR = 40,
>      P9_RREADDIR,
> +    P9_TLINK = 70,
> +    P9_RLINK,
>      P9_TVERSION = 100,
>      P9_RVERSION,
>      P9_TAUTH = 102,
> -- 
> 1.6.5.2

-aneesh