[PATCH v4 32/32] libxl_disk: Have libxl_cdrom_insert use libxl__ev_qmp

[Anthony PERARD <anthony.perard@citrix.com>]

So when QEMU is involve, the operation will be asynchrone and will
finish later.

This path reimplement libxl__qmp_insert_cdrom to make use of the new
libxl__ev_qmp API.  It also open the cdrom in libxl and send the FD via
QMP, so QEMU doesn't need access permition on the cdrom file.

libxl__qmp_insert_cdrom() is now async, libxl_cdrom_insert() is updated
to make use of it.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
---

Notes:
    v4:
        switch to the updated libxl__ev_qmp API

 tools/libxl/libxl_disk.c     |  42 +++++++++----
 tools/libxl/libxl_internal.h |  14 ++++-
 tools/libxl/libxl_qmp.c      | 117 +++++++++++++++++++++++++++++------
 3 files changed, 142 insertions(+), 31 deletions(-)

diff --git a/tools/libxl/libxl_disk.c b/tools/libxl/libxl_disk.c
index c759179628..eb086ed909 100644
--- a/tools/libxl/libxl_disk.c
+++ b/tools/libxl/libxl_disk.c
@@ -672,11 +672,14 @@ typedef struct {
     int dm_ver;
     int domid;
     libxl__domain_userdata_lock *lock;
+    libxl__qmp_insert_cdrom_state qics;
 } libxl__cdrom_insert_state;
 static void cdrom_insert_ejected(libxl__egc *egc,
-                                 libxl__cdrom_insert_state *cis);
+                                 libxl__qmp_insert_cdrom_state  *qics,
+                                 int rc);
 static void cdrom_insert_inserted(libxl__egc *egc,
-                                  libxl__cdrom_insert_state *cis);
+                                  libxl__qmp_insert_cdrom_state *qics,
+                                  int rc);
 static void cdrom_insert_done(libxl__egc *egc,
                               libxl__cdrom_insert_state *cis,
                               int rc);
@@ -777,12 +780,16 @@ int libxl_cdrom_insert(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk,
      * by inserting empty media. JSON is not updated.
      */
     if (cis->dm_ver == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
-        rc = libxl__qmp_insert_cdrom(gc, domid, disk_empty);
+        libxl__qmp_insert_cdrom_state *qics = &cis->qics;
+        qics->domid = domid;
+        qics->disk = disk_empty;
+        qics->callback = cdrom_insert_ejected;
+        rc = libxl__qmp_insert_cdrom(gc, qics);
         if (rc) goto out;
+    } else {
+        cdrom_insert_ejected(egc, &cis->qics, 0);
     }
 
-    cdrom_insert_ejected(egc, cis);
-
     return AO_INPROGRESS;
 
 out:
@@ -794,11 +801,12 @@ out:
 }
 
 static void cdrom_insert_ejected(libxl__egc *egc,
-                                 libxl__cdrom_insert_state *cis)
+                                 libxl__qmp_insert_cdrom_state *qics,
+                                 int rc)
 {
+    libxl__cdrom_insert_state *cis = CONTAINER_OF(qics, *cis, qics);
     STATE_AO_GC(cis->ao);
     uint32_t domid = cis->domid;
-    int rc;
     const char *be_path, *libxl_path;
     char * tmp;
     xs_transaction_t t = XBT_NULL;
@@ -808,6 +816,9 @@ static void cdrom_insert_ejected(libxl__egc *egc,
     libxl_device_disk *disk = cis->disk;
     libxl_device_disk *disk_saved = &cis->disk_saved;
 
+    if (rc)
+        goto out;
+
     be_path = cis->be_path;
     libxl_path = cis->libxl_path;
 
@@ -851,12 +862,15 @@ static void cdrom_insert_ejected(libxl__egc *egc,
     if (rc) goto out;
 
     if (cis->dm_ver == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
-        rc = libxl__qmp_insert_cdrom(gc, domid, disk);
+        qics->domid = domid;
+        qics->disk = disk;
+        qics->callback = cdrom_insert_inserted;
+        rc = libxl__qmp_insert_cdrom(gc, qics);
         if (rc) goto out;
+    } else {
+        cdrom_insert_inserted(egc, qics, 0);
     }
 
-    cdrom_insert_inserted(egc, cis);
-
     return;
 
 out:
@@ -865,11 +879,12 @@ out:
 }
 
 static void cdrom_insert_inserted(libxl__egc *egc,
-                                  libxl__cdrom_insert_state *cis)
+                                  libxl__qmp_insert_cdrom_state *qics,
+                                  int rc)
 {
+    libxl__cdrom_insert_state *cis = CONTAINER_OF(qics, *cis, qics);
     STATE_AO_GC(cis->ao);
     uint32_t domid = cis->domid;
-    int rc;
     const char *be_path, *libxl_path;
     char * tmp;
     xs_transaction_t t = XBT_NULL;
@@ -880,6 +895,9 @@ static void cdrom_insert_inserted(libxl__egc *egc,
     be_path = cis->be_path;
     libxl_path = cis->libxl_path;
 
+    if (rc)
+        goto out;
+
     insert = flexarray_make(gc, 4, 1);
     flexarray_append_pair(insert, "type",
                           libxl__device_disk_string_of_backend(disk->backend));
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index cafe8b5733..6b6ac65d00 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1948,7 +1948,19 @@ _hidden int libxl__qmp_resume(libxl__gc *gc, int domid);
 _hidden int libxl__qmp_restore(libxl__gc *gc, int domid, const char *filename);
 /* Set dirty bitmap logging status */
 _hidden int libxl__qmp_set_global_dirty_log(libxl__gc *gc, int domid, bool enable);
-_hidden int libxl__qmp_insert_cdrom(libxl__gc *gc, int domid, const libxl_device_disk *disk);
+
+typedef struct libxl__qmp_insert_cdrom_state libxl__qmp_insert_cdrom_state;
+struct libxl__qmp_insert_cdrom_state {
+    /* caller should include this in their own struct */
+    /* caller must fill these in, and they must all remain valid */
+    int domid;
+    const libxl_device_disk *disk;
+    void (*callback)(libxl__egc *egc, libxl__qmp_insert_cdrom_state *, int rc);
+    /* private to libxl__qmp_insert_cdrom() */
+    libxl__ev_qmp ev;
+};
+int libxl__qmp_insert_cdrom(libxl__gc *gc,
+                            libxl__qmp_insert_cdrom_state *qics);
 /* Add a virtual CPU */
 _hidden int libxl__qmp_cpu_add(libxl__gc *gc, int domid, int index);
 /* Query the bitmap of CPUs */
diff --git a/tools/libxl/libxl_qmp.c b/tools/libxl/libxl_qmp.c
index 07203a6fe6..08c8060095 100644
--- a/tools/libxl/libxl_qmp.c
+++ b/tools/libxl/libxl_qmp.c
@@ -1061,24 +1061,6 @@ int libxl__qmp_set_global_dirty_log(libxl__gc *gc, int domid, bool enable)
                            NULL, NULL);
 }
 
-int libxl__qmp_insert_cdrom(libxl__gc *gc, int domid,
-                            const libxl_device_disk *disk)
-{
-    libxl__json_object *args = NULL;
-    int dev_number = libxl__device_disk_dev_number(disk->vdev, NULL, NULL);
-
-    QMP_PARAMETERS_SPRINTF(&args, "device", "ide-%i", dev_number);
-
-    if (disk->format == LIBXL_DISK_FORMAT_EMPTY) {
-        return qmp_run_command(gc, domid, "eject", args, NULL, NULL);
-    } else {
-        qmp_parameters_add_string(gc, &args, "target", disk->pdev_path);
-        qmp_parameters_add_string(gc, &args, "arg",
-            libxl__qemu_disk_format_string(disk->format));
-        return qmp_run_command(gc, domid, "change", args, NULL, NULL);
-    }
-}
-
 int libxl__qmp_cpu_add(libxl__gc *gc, int domid, int idx)
 {
     libxl__json_object *args = NULL;
@@ -1395,6 +1377,105 @@ static void dm_state_saved(libxl__egc *egc, libxl__ev_qmp *ev,
 }
 
 
+static void qmp_insert_cdrom_addfd_cb(libxl__egc *egc, libxl__ev_qmp *ev,
+                                      const libxl__json_object *response,
+                                      int rc);
+static void qmp_insert_cdrom_done_cb(libxl__egc *egc, libxl__ev_qmp *ev,
+                                     const libxl__json_object *response,
+                                     int rc);
+int libxl__qmp_insert_cdrom(libxl__gc *gc,
+                            libxl__qmp_insert_cdrom_state *qics)
+{
+    int rc;
+    libxl__json_object *args = NULL;
+    int domid = qics->domid;
+    libxl__ev_qmp *ev =  &qics->ev;
+    const libxl_device_disk *disk = qics->disk;
+    int dev_number = libxl__device_disk_dev_number(disk->vdev, NULL, NULL);
+
+    libxl__ev_qmp_init(ev);
+    ev->domid = qics->domid;
+    ev->cfd = NULL;
+
+    if (disk->format == LIBXL_DISK_FORMAT_EMPTY) {
+        QMP_PARAMETERS_SPRINTF(&args, "device", "ide-%i", dev_number);
+        ev->callback = qmp_insert_cdrom_done_cb;
+        rc = libxl__ev_qmp_send(gc, ev, "eject", args);
+    } else {
+        libxl__carefd_begin();
+        ev->cfd = libxl__carefd_opened(CTX, open(disk->pdev_path, O_RDONLY));
+        if (!ev->cfd) {
+            LOGED(ERROR, domid,
+                  "Failed to open cdrom file %s", disk->pdev_path);
+            rc = ERROR_FAIL;
+            goto out;
+        }
+
+        /* This free form parameter is not use by QEMU or libxl. */
+        QMP_PARAMETERS_SPRINTF(&args, "opaque", "%s:%s",
+                               libxl_disk_format_to_string(disk->format),
+                               disk->pdev_path);
+        ev->callback = qmp_insert_cdrom_addfd_cb;
+        rc = libxl__ev_qmp_send(gc, ev, "add-fd", args);
+        if (rc)
+            goto out;
+    }
+out:
+    if (rc)
+        libxl__carefd_close(ev->cfd);
+    return rc;
+}
+
+static void qmp_insert_cdrom_addfd_cb(libxl__egc *egc, libxl__ev_qmp *ev,
+                                      const libxl__json_object *response,
+                                      int rc)
+{
+    EGC_GC;
+    libxl__qmp_insert_cdrom_state *qics = CONTAINER_OF(ev, *qics, ev);
+    libxl__json_object *args = NULL;
+    const libxl__json_object *o;
+    const libxl_device_disk *disk = qics->disk;
+    int dev_number = libxl__device_disk_dev_number(disk->vdev, NULL, NULL);
+    int fdset;
+
+    libxl__carefd_close(ev->cfd);
+    ev->cfd = NULL;
+
+    if (rc)
+        goto out;
+
+    o = libxl__json_map_get("fdset-id", response, JSON_INTEGER);
+    if (!o) {
+        rc = ERROR_FAIL;
+        goto out;
+    }
+    fdset = libxl__json_object_get_integer(o);
+
+    ev->callback = qmp_insert_cdrom_done_cb;
+    QMP_PARAMETERS_SPRINTF(&args, "device", "ide-%i", dev_number);
+    QMP_PARAMETERS_SPRINTF(&args, "target", "/dev/fdset/%d", fdset);
+    qmp_parameters_add_string(gc, &args, "arg",
+                              libxl__qemu_disk_format_string(disk->format));
+    rc = libxl__ev_qmp_send(gc, ev, "change", args);
+    if (rc)
+        goto out;
+    return;
+out:
+    qmp_insert_cdrom_done_cb(egc, ev, NULL, rc);
+}
+
+static void qmp_insert_cdrom_done_cb(libxl__egc *egc, libxl__ev_qmp *ev,
+                                     const libxl__json_object *response,
+                                     int rc)
+{
+    EGC_GC;
+    libxl__qmp_insert_cdrom_state *qics = CONTAINER_OF(ev, *qics, ev);
+
+    libxl__ev_qmp_dispose(gc, ev);
+
+    qics->callback(egc, qics, rc);
+}
+
 
 /* ------------ Implementation of libxl__ev_qmp ---------------- */
 
-- 
Anthony PERARD


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