tools/xen-9pfsd: add 9pfs stat request support

Add the stat request of the 9pfs protocol.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Jason Andryuk <jandryuk@gmail.com>

tools/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,
@@ -166,6 +186,7 @@ static void fmt_err(const char *fmt)
  * S: String (2 byte length + <length> characters)
  *    The length is obtained via strlen() of the parameter, being a pointer
  *    to the first character of the string
+ * s: stat (struct p9_stat)
  * U: 4 byte unsigned integer
  *    The parameter is a pointer to a uint32_t value
  */
@@ -176,6 +197,8 @@ static void vfill_buffer_at(void **data, const char *fmt, va_list ap)
     const void *par;
     const char *str_val;
     const struct p9_qid *qid;
+    const struct p9_stat *stat;
+    uint16_t tlen;
     unsigned int len;
     unsigned int array_sz = 0;
     unsigned int elem_sz = 0;
@@ -259,6 +282,18 @@ static void vfill_buffer_at(void **data, const char *fmt, va_list ap)
             *data += len;
             break;
 
+        case 's':
+            stat = par;
+            elem_sz = sizeof(*stat);
+            tlen = stat->size + sizeof(stat->size);
+            fill_buffer_at(data, "uuuUQUUULSSSSSUUU", &tlen, &stat->size,
+                           &stat->type, &stat->dev, &stat->qid, &stat->mode,
+                           &stat->atime, &stat->mtime, &stat->length,
+                           stat->name, stat->uid, stat->gid, stat->muid,
+                           stat->extension, &stat->n_uid, &stat->n_gid,
+                           &stat->n_muid);
+            break;
+
         case 'U':
             put_unaligned(*(const uint32_t *)par, (uint32_t *)*data);
             elem_sz = sizeof(uint32_t);
@@ -1146,6 +1181,69 @@ 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;
+    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, fidp->path, &st, 0) < 0 )
+    {
+        p9_error(ring, hdr->tag, errno);
+        goto out;
+    }
+    fill_p9_stat(device, &p9s, &st, strrchr(fidp->path, '/') + 1);
+
+    fill_buffer(ring, hdr->cmd + 1, hdr->tag, "s", &p9s);
+
+ out:
+    free_fid(device, fidp);
+}
+
 void *io_thread(void *arg)
 {
     struct ring *ring = arg;
@@ -1225,6 +1323,10 @@ 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);