[PATCH v3 1/7] libxl: libxl__device_disk_local_attach return a new libxl_device_disk

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

- make libxl_device_disk_local_attach/detach two internal functions;

- pass a gc rather than a ctx to them;

- introduce a new libxl_device_disk** parameter to
libxl__device_disk_local_attach, the parameter is allocated on the gc by
libxl__device_disk_local_attach. It is going to fill it with
informations about the new locally attached disk.  The new
libxl_device_disk should be passed to libxl_device_disk_local_detach
afterwards.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 tools/libxl/libxl.c            |   73 -----------------------------------
 tools/libxl/libxl.h            |    7 ---
 tools/libxl/libxl_bootloader.c |    9 ++--
 tools/libxl/libxl_internal.c   |   82 ++++++++++++++++++++++++++++++++++++++++
 tools/libxl/libxl_internal.h   |   11 +++++
 5 files changed, 97 insertions(+), 85 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 60dbfdc..e645d2a 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -1664,79 +1664,6 @@ out:
     return ret;
 }
 
-char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk)
-{
-    GC_INIT(ctx);
-    char *dev = NULL;
-    char *ret = NULL;
-    int rc;
-
-    rc = libxl__device_disk_setdefault(gc, disk);
-    if (rc) goto out;
-
-    switch (disk->backend) {
-        case LIBXL_DISK_BACKEND_PHY:
-            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching PHY disk %s",
-                       disk->pdev_path);
-            dev = disk->pdev_path;
-            break;
-        case LIBXL_DISK_BACKEND_TAP:
-            switch (disk->format) {
-            case LIBXL_DISK_FORMAT_RAW:
-                /* optimise away the early tapdisk attach in this case */
-                LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching"
-                           " tap disk %s directly (ie without using blktap)",
-                           disk->pdev_path);
-                dev = disk->pdev_path;
-                break;
-            case LIBXL_DISK_FORMAT_VHD:
-                dev = libxl__blktap_devpath(gc, disk->pdev_path,
-                                            disk->format);
-                break;
-            case LIBXL_DISK_FORMAT_QCOW:
-            case LIBXL_DISK_FORMAT_QCOW2:
-                abort(); /* prevented by libxl__device_disk_set_backend */
-            default:
-                LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
-                           "unrecognized disk format: %d", disk->format);
-                break;
-            }
-            break;
-        case LIBXL_DISK_BACKEND_QDISK:
-            if (disk->format != LIBXL_DISK_FORMAT_RAW) {
-                LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot locally"
-                           " attach a qdisk image if the format is not raw");
-                break;
-            }
-            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching qdisk %s\n",
-                       disk->pdev_path);
-            dev = disk->pdev_path;
-            break;
-        default:
-            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend "
-                "type: %d", disk->backend);
-            break;
-    }
-
- out:
-    if (dev != NULL)
-        ret = strdup(dev);
-    GC_FREE;
-    return ret;
-}
-
-int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk)
-{
-    /* Nothing to do for PHYSTYPE_PHY. */
-
-    /*
-     * For other device types assume that the blktap2 process is
-     * needed by the soon to be started domain and do nothing.
-     */
-
-    return 0;
-}
-
 /******************************************************************************/
 
 int libxl__device_nic_setdefault(libxl__gc *gc, libxl_device_nic *nic)
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index edbca53..779c8dd 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -618,13 +618,6 @@ int libxl_device_disk_getinfo(libxl_ctx *ctx, uint32_t domid,
  */
 int libxl_cdrom_insert(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk);
 
-/*
- * Make a disk available in this (the control) domain. Returns path to
- * a device.
- */
-char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk);
-int libxl_device_disk_local_detach(libxl_ctx *ctx, libxl_device_disk *disk);
-
 /* Network Interfaces */
 int libxl_device_nic_add(libxl_ctx *ctx, uint32_t domid, libxl_device_nic *nic);
 int libxl_device_nic_remove(libxl_ctx *ctx, uint32_t domid,
diff --git a/tools/libxl/libxl_bootloader.c b/tools/libxl/libxl_bootloader.c
index 2774062..429253d 100644
--- a/tools/libxl/libxl_bootloader.c
+++ b/tools/libxl/libxl_bootloader.c
@@ -330,6 +330,7 @@ int libxl_run_bootloader(libxl_ctx *ctx,
     char *fifo = NULL;
     char *diskpath = NULL;
     char **args = NULL;
+    libxl_device_disk *tmpdisk = NULL;
 
     char tempdir_template[] = "/var/run/libxl/bl.XXXXXX";
     char *tempdir;
@@ -386,7 +387,7 @@ int libxl_run_bootloader(libxl_ctx *ctx,
         goto out_close;
     }
 
-    diskpath = libxl_device_disk_local_attach(ctx, disk);
+    diskpath = libxl__device_disk_local_attach(gc, disk, &tmpdisk);
     if (!diskpath) {
         goto out_close;
     }
@@ -452,10 +453,8 @@ int libxl_run_bootloader(libxl_ctx *ctx,
 
     rc = 0;
 out_close:
-    if (diskpath) {
-        libxl_device_disk_local_detach(ctx, disk);
-        free(diskpath);
-    }
+    if (tmpdisk)
+        libxl__device_disk_local_detach(gc, tmpdisk);
     if (fifo_fd > -1)
         close(fifo_fd);
     if (bootloader_fd > -1)
diff --git a/tools/libxl/libxl_internal.c b/tools/libxl/libxl_internal.c
index b89aef7..95fb918 100644
--- a/tools/libxl/libxl_internal.c
+++ b/tools/libxl/libxl_internal.c
@@ -323,6 +323,88 @@ out:
     return rc;
 }
 
+_hidden char * libxl__device_disk_local_attach(libxl__gc *gc,
+        const libxl_device_disk *disk,
+        libxl_device_disk **new_disk)
+{
+    libxl_ctx *ctx = gc->owner;
+    char *dev = NULL;
+    int rc;
+    libxl_device_disk *tmpdisk = libxl__zalloc(gc, sizeof(libxl_device_disk));
+    if (tmpdisk == NULL) goto out;
+
+    *new_disk = tmpdisk;
+    memcpy(tmpdisk, disk, sizeof(libxl_device_disk));
+    if (disk->pdev_path != NULL)
+        tmpdisk->pdev_path = libxl__strdup(gc, disk->pdev_path);
+    if (disk->script != NULL)
+        tmpdisk->script = libxl__strdup(gc, disk->script);
+    tmpdisk->vdev = NULL;
+
+    rc = libxl__device_disk_setdefault(gc, tmpdisk);
+    if (rc) goto out;
+
+    switch (tmpdisk->backend) {
+        case LIBXL_DISK_BACKEND_PHY:
+            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching PHY disk %s",
+                       tmpdisk->pdev_path);
+            dev = tmpdisk->pdev_path;
+            break;
+        case LIBXL_DISK_BACKEND_TAP:
+            switch (tmpdisk->format) {
+            case LIBXL_DISK_FORMAT_RAW:
+                /* optimise away the early tapdisk attach in this case */
+                LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching"
+                           " tap disk %s directly (ie without using blktap)",
+                           tmpdisk->pdev_path);
+                dev = tmpdisk->pdev_path;
+                break;
+            case LIBXL_DISK_FORMAT_VHD:
+                dev = libxl__blktap_devpath(gc, tmpdisk->pdev_path,
+                                            tmpdisk->format);
+                break;
+            case LIBXL_DISK_FORMAT_QCOW:
+            case LIBXL_DISK_FORMAT_QCOW2:
+                abort(); /* prevented by libxl__device_disk_set_backend */
+            default:
+                LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
+                           "unrecognized disk format: %d", tmpdisk->format);
+                break;
+            }
+            break;
+        case LIBXL_DISK_BACKEND_QDISK:
+            if (tmpdisk->format != LIBXL_DISK_FORMAT_RAW) {
+                LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot locally"
+                           " attach a qdisk image if the format is not raw");
+                break;
+            }
+            LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching qdisk %s\n",
+                       disk->pdev_path);
+            dev = tmpdisk->pdev_path;
+            break;
+        default:
+            LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend "
+                "type: %d", tmpdisk->backend);
+            break;
+    }
+
+ out:
+    return dev;
+}
+
+_hidden int libxl__device_disk_local_detach(libxl__gc *gc,
+        libxl_device_disk *disk)
+{
+    /* Nothing to do for PHYSTYPE_PHY. */
+
+    /*
+     * For other device types assume that the blktap2 process is
+     * needed by the soon to be started domain and do nothing.
+     */
+
+    return 0;
+}
+
 libxl_device_model_version libxl__device_model_version_running(libxl__gc *gc,
                                                                uint32_t domid)
 {
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index a4b933b..4e0d203 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1001,6 +1001,17 @@ _hidden char *libxl__blktap_devpath(libxl__gc *gc,
  */
 _hidden void libxl__device_destroy_tapdisk(libxl__gc *gc, char *be_path);
 
+/*
+ * Make a disk available in this (the control) domain. Returns path to
+ * a device.
+ */
+_hidden char * libxl__device_disk_local_attach(libxl__gc *gc,
+        const libxl_device_disk *disk,
+        libxl_device_disk **new_disk);
+_hidden int libxl__device_disk_local_detach(libxl__gc *gc,
+        libxl_device_disk *disk);
+
+
 _hidden char *libxl__uuid2string(libxl__gc *gc, const libxl_uuid uuid);
 
 struct libxl__xen_console_reader {
-- 
1.7.2.5