[Qemu-devel] [PATCH -V3 05/32] virtio-9p: Implement P9_TWALK

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

From: Anthony Liguori <aliguori@us.ibm.com>

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 hw/virtio-9p-local.c |   12 +++
 hw/virtio-9p.c       |  219 +++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 229 insertions(+), 2 deletions(-)

diff --git a/hw/virtio-9p-local.c b/hw/virtio-9p-local.c
index aefb5a8..409f5b0 100644
--- a/hw/virtio-9p-local.c
+++ b/hw/virtio-9p-local.c
@@ -78,10 +78,22 @@ static ssize_t local_readlink(void *opaque, const char *path,
     return readlink(rpath(path), buf, bufsz);
 }
 
+static int local_close(void *opaque, int fd)
+{
+    return close(fd);
+}
+
+static int local_closedir(void *opaque, DIR *dir)
+{
+    return closedir(dir);
+}
+
 static V9fsPosixFileOperations ops = {
     .lstat = local_lstat,
     .setuid = local_setuid,
     .readlink = local_readlink,
+    .close = local_close,
+    .closedir = local_closedir,
 };
 
 V9fsPosixFileOperations *virtio_9p_init_local(const char *path)
diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c
index de5f6b0..784d399 100644
--- a/hw/virtio-9p.c
+++ b/hw/virtio-9p.c
@@ -117,6 +117,22 @@ static ssize_t posix_readlink(V9fsState *s, V9fsString *path, V9fsString *buf)
     return len;
 }
 
+static int posix_close(V9fsState *s, int fd)
+{
+    return s->ops->close(s->ops->opaque, fd);
+}
+
+static int posix_closedir(V9fsState *s, DIR *dir)
+{
+    return s->ops->closedir(s->ops->opaque, dir);
+}
+
+static void v9fs_string_init(V9fsString *str)
+{
+    str->data = NULL;
+    str->size = 0;
+}
+
 static void v9fs_string_free(V9fsString *str)
 {
     qemu_free(str->data);
@@ -144,6 +160,12 @@ static void v9fs_string_sprintf(V9fsString *str, const char *fmt, ...)
     str->size = err;
 }
 
+static void v9fs_string_copy(V9fsString *lhs, V9fsString *rhs)
+{
+    v9fs_string_free(lhs);
+    v9fs_string_sprintf(lhs, "%s", rhs->data);
+}
+
 static size_t v9fs_string_size(V9fsString *str)
 {
     return str->size;
@@ -184,6 +206,31 @@ static V9fsFidState *alloc_fid(V9fsState *s, int32_t fid)
     return f;
 }
 
+static int free_fid(V9fsState *s, int32_t fid)
+{
+    V9fsFidState **fidpp, *fidp;
+
+    for (fidpp = &s->fid_list; *fidpp; fidpp = &(*fidpp)->next) {
+        if ((*fidpp)->fid == fid)
+            break;
+    }
+
+    if (*fidpp == NULL)
+        return -ENOENT;
+
+    fidp = *fidpp;
+    *fidpp = fidp->next;
+
+    if (fidp->fd != -1)
+        posix_close(s, fidp->fd);
+    if (fidp->dir)
+        posix_closedir(s, fidp->dir);
+    v9fs_string_free(&fidp->path);
+    qemu_free(fidp);
+
+    return 0;
+}
+
 #define P9_QID_TYPE_DIR		0x80
 #define P9_QID_TYPE_SYMLINK	0x02
 
@@ -689,10 +736,178 @@ out:
     qemu_free(vs);
 }
 
+typedef struct V9fsWalkState {
+    V9fsPDU *pdu;
+    size_t offset;
+    int32_t fid;
+    int32_t newfid;
+    int16_t nwnames;
+    int name_idx;
+    V9fsQID *qids;
+    V9fsFidState *fidp;
+    V9fsFidState *newfidp;
+    V9fsString path;
+    V9fsString *wnames;
+    struct stat stbuf;
+} V9fsWalkState;
+
+static void v9fs_walk_complete(V9fsState *s, V9fsWalkState *vs, int err)
+{
+    complete_pdu(s, vs->pdu, err);
+
+    if(vs->nwnames) {
+        for (vs->name_idx = 0; vs->name_idx < vs->nwnames; vs->name_idx++)
+            v9fs_string_free(&vs->wnames[vs->name_idx]);
+
+        qemu_free(vs->wnames);
+        qemu_free(vs->qids);
+    }
+}
+
+static void v9fs_walk_marshal(V9fsWalkState *vs)
+{
+    int i;
+    vs->offset = 7;
+    vs->offset += pdu_marshal(vs->pdu, vs->offset, "w", vs->nwnames);
+
+    for (i = 0; i < vs->nwnames; i++)
+        vs->offset += pdu_marshal(vs->pdu, vs->offset, "Q", &vs->qids[i]);
+}
+
+static void v9fs_walk_post_newfid_lstat(V9fsState *s, V9fsWalkState *vs,
+                                                                int err)
+{
+    if (err == -1) {
+        free_fid(s, vs->newfid);
+        v9fs_string_free(&vs->path);
+        err = -ENOENT;
+        goto out;
+    }
+
+    stat_to_qid(&vs->stbuf, &vs->qids[vs->name_idx]);
+
+    vs->name_idx++;
+    if (vs->name_idx < vs->nwnames) {
+        v9fs_string_sprintf(&vs->path, "%s/%s", vs->newfidp->path.data,
+                                            vs->wnames[vs->name_idx].data);
+        v9fs_string_copy(&vs->newfidp->path, &vs->path);
+
+        err = posix_lstat(s, &vs->newfidp->path, &vs->stbuf);
+        v9fs_walk_post_newfid_lstat(s, vs, err);
+        return;
+    }
+
+    v9fs_string_free(&vs->path);
+    v9fs_walk_marshal(vs);
+    err = vs->offset;
+out:
+    v9fs_walk_complete(s, vs, err);
+}
+
+static void v9fs_walk_post_oldfid_lstat(V9fsState *s, V9fsWalkState *vs,
+        int err)
+{
+    if (err == -1) {
+        v9fs_string_free(&vs->path);
+        err = -ENOENT;
+        goto out;
+    }
+
+    stat_to_qid(&vs->stbuf, &vs->qids[vs->name_idx]);
+    vs->name_idx++;
+    if (vs->name_idx < vs->nwnames) {
+
+        v9fs_string_sprintf(&vs->path, "%s/%s",
+                vs->fidp->path.data, vs->wnames[vs->name_idx].data);
+        v9fs_string_copy(&vs->fidp->path, &vs->path);
+
+        err = posix_lstat(s, &vs->fidp->path, &vs->stbuf);
+        v9fs_walk_post_oldfid_lstat(s, vs, err);
+        return;
+    }
+
+    v9fs_string_free(&vs->path);
+    v9fs_walk_marshal(vs);
+    err = vs->offset;
+out:
+    v9fs_walk_complete(s, vs, err);
+}
+
 static void v9fs_walk(V9fsState *s, V9fsPDU *pdu)
 {
-    if (debug_9p_pdu)
-        pprint_pdu(pdu);
+    V9fsWalkState *vs;
+    int err = 0;
+    int i;
+
+    vs = qemu_malloc(sizeof(*vs));
+    vs->pdu =pdu;
+    vs->wnames = NULL;
+    vs->qids = NULL;
+    vs->offset = 7;
+
+    vs->offset += pdu_unmarshal(vs->pdu, vs->offset, "ddw", &vs->fid,
+                                            &vs->newfid, &vs->nwnames);
+
+    if(vs->nwnames) {
+        vs->wnames = qemu_mallocz(sizeof(vs->wnames[0]) * vs->nwnames);
+        BUG_ON(vs->wnames == NULL);
+
+        vs->qids = qemu_mallocz(sizeof(vs->qids[0]) * vs->nwnames);
+        BUG_ON(vs->qids == NULL);
+
+        for (i = 0; i < vs->nwnames; i++) {
+            vs->offset += pdu_unmarshal(vs->pdu, vs->offset, "s",
+                                            &vs->wnames[i]);
+        }
+    }
+
+    vs->fidp = lookup_fid(s, vs->fid);
+    if (vs->fidp == NULL) {
+        err = -ENOENT;
+        goto out;
+    }
+
+    /* FIXME: is this really valid? */
+    if (vs->fid == vs->newfid) {
+        v9fs_string_init(&vs->path);
+        vs->name_idx = 0;
+
+        if (vs->name_idx < vs->nwnames) {
+            v9fs_string_sprintf(&vs->path, "%s/%s",
+                vs->fidp->path.data, vs->wnames[vs->name_idx].data);
+            v9fs_string_copy(&vs->fidp->path, &vs->path);
+
+            err = posix_lstat(s, &vs->fidp->path, &vs->stbuf);
+            v9fs_walk_post_oldfid_lstat(s, vs, err);
+            return;
+        }
+    } else {
+        vs->newfidp = alloc_fid(s, vs->newfid);
+        if (vs->newfidp == NULL) {
+            err = -EINVAL;
+            goto out;
+        }
+
+        vs->newfidp->uid = vs->fidp->uid;
+        v9fs_string_init(&vs->path);
+        vs->name_idx = 0;
+        v9fs_string_copy(&vs->newfidp->path, &vs->fidp->path);
+
+        if (vs->name_idx < vs->nwnames) {
+            v9fs_string_sprintf(&vs->path, "%s/%s", vs->newfidp->path.data,
+                                vs->wnames[vs->name_idx].data);
+            v9fs_string_copy(&vs->newfidp->path, &vs->path);
+
+            err = posix_lstat(s, &vs->newfidp->path, &vs->stbuf);
+            v9fs_walk_post_newfid_lstat(s, vs, err);
+            return;
+        }
+    }
+
+    v9fs_walk_marshal(vs);
+    err = vs->offset;
+out:
+    v9fs_walk_complete(s, vs, err);
 }
 
 static void v9fs_clunk(V9fsState *s, V9fsPDU *pdu)
-- 
1.7.0.2.323.g0d092