[PATCH v3 13/33] tools/xenlogd: add 9pfs stat request support

[Juergen Gross <jgross@xxxxxxxx>]

Add the stat request of the 9pfs protocol.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
V3:
- use fstatat() (Jason Andryuk)
---
 tools/xen-9pfsd/io.c | 93 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

diff --git a/tools/xen-9pfsd/io.c b/tools/xen-9pfsd/io.c
index 9d816dc97e..7d40747b60 100644
--- a/tools/xen-9pfsd/io.c
+++ b/tools/xen-9pfsd/io.c
@@ -34,6 +34,7 @@
 #define P9_CMD_OPEN       112
 #define P9_CMD_CREATE     114
 #define P9_CMD_CLUNK      120
+#define P9_CMD_STAT       124
 
 /* P9 protocol open flags. */
 #define P9_OREAD            0   /* read */
@@ -60,6 +61,25 @@ struct p9_qid {
     uint64_t path;
 };
 
+struct p9_stat {
+    uint16_t size;
+    uint16_t type;
+    uint32_t dev;
+    struct p9_qid qid;
+    uint32_t mode;
+    uint32_t atime;
+    uint32_t mtime;
+    uint64_t length;
+    const char *name;
+    const char *uid;
+    const char *gid;
+    const char *muid;
+    const char *extension;
+    uint32_t n_uid;
+    uint32_t n_gid;
+    uint32_t n_muid;
+};
+
 /*
  * Note that the ring names "in" and "out" are from the frontend's
  * perspective, so the "in" ring will be used for responses to the frontend,
@@ -1140,6 +1160,75 @@ static void p9_clunk(struct ring *ring, struct p9_header 
*hdr)
     fill_buffer(ring, hdr->cmd + 1, hdr->tag, "");
 }
 
+static void fill_p9_stat(device *device, struct p9_stat *p9s, struct stat *st,
+                         const char *name)
+{
+    memset(p9s, 0, sizeof(*p9s));
+    fill_qid(device, NULL, &p9s->qid, st);
+    p9s->mode = st->st_mode & 0777;
+    if ( S_ISDIR(st->st_mode) )
+        p9s->mode |= P9_CREATE_PERM_DIR;
+    p9s->atime = st->st_atime;
+    p9s->mtime = st->st_mtime;
+    p9s->length = st->st_size;
+    p9s->name = name;
+    p9s->uid = "";
+    p9s->gid = "";
+    p9s->muid = "";
+    p9s->extension = "";
+    p9s->n_uid = 0;
+    p9s->n_gid = 0;
+    p9s->n_muid = 0;
+
+    /*
+     * Size of individual fields without the size field, including 5 2-byte
+     * string length fields.
+     */
+    p9s->size = 71 + strlen(p9s->name);
+}
+
+static void p9_stat(struct ring *ring, struct p9_header *hdr)
+{
+    device *device = ring->device;
+    uint32_t fid;
+    struct p9_fid *fidp;
+    struct p9_stat p9s;
+    struct stat st;
+    uint16_t total_length;
+    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 ( fstatat(device->root_fd, relpath_from_path(fidp->path), &st, 0) < 0 )
+    {
+        p9_error(ring, hdr->tag, errno);
+        goto out;
+    }
+    fill_p9_stat(device, &p9s, &st, strrchr(fidp->path, '/') + 1);
+
+    total_length = p9s.size + sizeof(p9s.size);
+    fill_buffer(ring, hdr->cmd + 1, hdr->tag, "uuuUQUUULSSSSSUUU",
+                &total_length, &p9s.size, &p9s.type, &p9s.dev, &p9s.qid,
+                &p9s.mode, &p9s.atime, &p9s.mtime, &p9s.length, p9s.name,
+                p9s.uid, p9s.gid, p9s.muid, p9s.extension, &p9s.n_uid,
+                &p9s.n_gid, &p9s.n_muid);
+
+ out:
+    free_fid(device, fidp);
+}
+
 void *io_thread(void *arg)
 {
     struct ring *ring = arg;
@@ -1219,6 +1308,10 @@ void *io_thread(void *arg)
                 p9_clunk(ring, &hdr);
                 break;
 
+            case P9_CMD_STAT:
+                p9_stat(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