[PATCH v3 11/33] tools/xenlogd: add 9pfs clunk request support

[Juergen Gross <jgross@xxxxxxxx>]

Add the clunk request of the 9pfs protocol.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- use unlinkat() (Jason Andryuk)
---
 tools/xen-9pfsd/io.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/tools/xen-9pfsd/io.c b/tools/xen-9pfsd/io.c
index e7db90a972..4adef6715f 100644
--- a/tools/xen-9pfsd/io.c
+++ b/tools/xen-9pfsd/io.c
@@ -32,6 +32,7 @@
 #define P9_CMD_ERROR      107
 #define P9_CMD_WALK       110
 #define P9_CMD_OPEN       112
+#define P9_CMD_CLUNK      120
 
 /* P9 protocol open flags. */
 #define P9_OREAD            0   /* read */
@@ -950,6 +951,44 @@ static void p9_open(struct ring *ring, struct p9_header 
*hdr)
     p9_error(ring, hdr->tag, errno);
 }
 
+static void p9_clunk(struct ring *ring, struct p9_header *hdr)
+{
+    device *device = ring->device;
+    uint32_t fid;
+    struct p9_fid *fidp;
+    int ret;
+
+    ret = fill_data(ring, "U", &fid);
+    if ( ret != 1 )
+    {
+        p9_error(ring, hdr->tag, EINVAL);
+        return;
+    }
+
+    fidp = get_fid_ref(device, fid);
+    if ( !fidp )
+    {
+        p9_error(ring, hdr->tag, ENOENT);
+        return;
+    }
+
+    if ( fidp->opened )
+    {
+        fidp->opened = false;
+        free_fid(device, fidp);
+        close(fidp->fd);
+        if ( fidp->mode & P9_OREMOVE )
+            unlinkat(device->root_fd, relpath_from_path(fidp->path),
+                     fidp->isdir ? AT_REMOVEDIR : 0);
+    }
+
+    /* 2 calls of free_fid(): one for our reference, and one to free it. */
+    free_fid(device, fidp);
+    free_fid(device, fidp);
+
+    fill_buffer(ring, hdr->cmd + 1, hdr->tag, "");
+}
+
 void *io_thread(void *arg)
 {
     struct ring *ring = arg;
@@ -1021,6 +1060,10 @@ void *io_thread(void *arg)
                 p9_open(ring, &hdr);
                 break;
 
+            case P9_CMD_CLUNK:
+                p9_clunk(ring, &hdr);
+                break;
+
             default:
                 syslog(LOG_DEBUG, "%u.%u sent unhandled command %u\n",
                        ring->device->domid, ring->device->devid, hdr.cmd);
-- 
2.35.3