[PATCH v4 2/8] libxl: libxl__device_disk_local_attach return a new libxl_device_disk

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

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_bootloader.c |   10 ++++----
 tools/libxl/libxl_internal.c   |   47 +++++++++++++++++++++++----------------
 tools/libxl/libxl_internal.h   |    3 +-
 3 files changed, 35 insertions(+), 25 deletions(-)

diff --git a/tools/libxl/libxl_bootloader.c b/tools/libxl/libxl_bootloader.c
index 977c6d3..83cac78 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;
@@ -386,8 +387,9 @@ int libxl_run_bootloader(libxl_ctx *ctx,
         goto out_close;
     }
 
-    diskpath = libxl__device_disk_local_attach(gc, disk);
+    diskpath = libxl__device_disk_local_attach(gc, disk, &tmpdisk);
     if (!diskpath) {
+        rc = ERROR_FAIL;
         goto out_close;
     }
 
@@ -452,10 +454,8 @@ int libxl_run_bootloader(libxl_ctx *ctx,
 
     rc = 0;
 out_close:
-    if (diskpath) {
-        libxl__device_disk_local_detach(gc, 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 1f428b2..3af77e7 100644
--- a/tools/libxl/libxl_internal.c
+++ b/tools/libxl/libxl_internal.c
@@ -323,64 +323,73 @@ out:
     return rc;
 }
 
-_hidden char * libxl__device_disk_local_attach(libxl__gc *gc, libxl_device_disk *disk)
+_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;
-    char *ret = NULL;
     int rc;
-
-    rc = libxl__device_disk_setdefault(gc, disk);
+    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 (disk->backend) {
+    switch (tmpdisk->backend) {
         case LIBXL_DISK_BACKEND_PHY:
             LIBXL__LOG(ctx, LIBXL__LOG_DEBUG, "locally attaching PHY disk %s",
-                       disk->pdev_path);
-            dev = disk->pdev_path;
+                       tmpdisk->pdev_path);
+            dev = tmpdisk->pdev_path;
             break;
         case LIBXL_DISK_BACKEND_TAP:
-            switch (disk->format) {
+            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)",
-                           disk->pdev_path);
-                dev = disk->pdev_path;
+                           tmpdisk->pdev_path);
+                dev = tmpdisk->pdev_path;
                 break;
             case LIBXL_DISK_FORMAT_VHD:
-                dev = libxl__blktap_devpath(gc, disk->pdev_path,
-                                            disk->format);
+                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", disk->format);
+                           "unrecognized disk format: %d", tmpdisk->format);
                 break;
             }
             break;
         case LIBXL_DISK_BACKEND_QDISK:
-            if (disk->format != LIBXL_DISK_FORMAT_RAW) {
+            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 = disk->pdev_path;
+            dev = tmpdisk->pdev_path;
             break;
         default:
             LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk backend "
-                "type: %d", disk->backend);
+                "type: %d", tmpdisk->backend);
             break;
     }
 
  out:
-    if (dev != NULL)
-        ret = strdup(dev);
-    return ret;
+    return dev;
 }
 
 _hidden int libxl__device_disk_local_detach(libxl__gc *gc, libxl_device_disk *disk)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 6927aef..2f1cf0f 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -1006,7 +1006,8 @@ _hidden void libxl__device_destroy_tapdisk(libxl__gc *gc, char *be_path);
  * a device.
  */
 _hidden char * libxl__device_disk_local_attach(libxl__gc *gc,
-        libxl_device_disk *disk);
+        const libxl_device_disk *disk,
+        libxl_device_disk **new_disk);
 _hidden int libxl__device_disk_local_detach(libxl__gc *gc,
         libxl_device_disk *disk);
 
-- 
1.7.2.5