libxl/xl: support empty disk paths (ejected cdroms)

Support empty disk paths, including in domain config files, for
compatibility with xend.  This allows a domain to be created with a
cdrom which is initially in the "ejected" (no cd present) state.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

4 files changed, 16 insertions, 6 deletions

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index c4477c7c52..93a22d2024 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -646,8 +646,8 @@ int libxl_event_get_disk_eject_info(libxl_ctx *ctx, uint32_t domid, libxl_event
 
     disk->backend_domid = 0;
     disk->domid = domid;
-    disk->physpath = NULL;
-    disk->phystype = 0;
+    disk->physpath = strdup("");
+    disk->phystype = PHYSTYPE_EMPTY;
     /* this value is returned to the user: do not free right away */
     disk->virtpath = libxl__xs_read(&gc, XBT_NULL, libxl__sprintf(&gc, "%s/dev", backend));
     disk->unpluggable = 1;
@@ -882,6 +882,8 @@ int libxl_device_disk_add(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *dis
             device.backend_kind = DEVICE_VBD;
             break;
         }
+        case PHYSTYPE_EMPTY:
+            break;
         case PHYSTYPE_FILE:
             /* let's pretend is tap:aio for the moment */
             disk->phystype = PHYSTYPE_AIO;
@@ -1606,7 +1608,7 @@ static unsigned int libxl_append_disk_list_of_type(libxl_ctx *ctx,
             pdisk->backend_domid = 0;
             pdisk->domid = domid;
             physpath_tmp = xs_read(ctx->xsh, XBT_NULL, libxl__sprintf(&gc, "%s/%s/params", be_path, *dir), &len);
-            if (strchr(physpath_tmp, ':')) {
+            if (physpath_tmp && strchr(physpath_tmp, ':')) {
                 pdisk->physpath = strdup(strchr(physpath_tmp, ':') + 1);
                 free(physpath_tmp);
             } else {
@@ -1684,7 +1686,7 @@ int libxl_cdrom_insert(libxl_ctx *ctx, uint32_t domid, libxl_device_disk *disk)
 
     if (!disk->physpath) {
         disk->physpath = strdup("");
-        disk->phystype = PHYSTYPE_PHY;
+        disk->phystype = PHYSTYPE_EMPTY;
     }
     disks = libxl_device_disk_list(ctx, domid, &num);
     for (i = 0; i < num; i++) {
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index cf97b7c3b3..1160de3c8c 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -178,6 +178,7 @@ typedef enum {
     PHYSTYPE_AIO,
     PHYSTYPE_FILE,
     PHYSTYPE_PHY,
+    PHYSTYPE_EMPTY,
 } libxl_disk_phystype;
 
 typedef enum {
diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
index 2d430b7ffe..cf694d2f82 100644
--- a/tools/libxl/libxl_device.c
+++ b/tools/libxl/libxl_device.c
@@ -130,6 +130,7 @@ char *libxl__device_disk_string_of_phystype(libxl_disk_phystype phystype)
         case PHYSTYPE_AIO: return "aio";
         case PHYSTYPE_FILE: return "file";
         case PHYSTYPE_PHY: return "phy";
+        case PHYSTYPE_EMPTY: return "file";
         default: return NULL;
     }
 }
@@ -143,6 +144,7 @@ char *libxl__device_disk_backend_type_of_phystype(libxl_disk_phystype phystype)
         case PHYSTYPE_AIO: return "tap";
         /* let's pretend file is tap:aio */
         case PHYSTYPE_FILE: return "tap";
+        case PHYSTYPE_EMPTY: return "tap";
         case PHYSTYPE_PHY: return "phy";
         default: return NULL;
     }
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 5f2cab299a..ba2bc29e4b 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -457,6 +457,11 @@ static int parse_disk_config(libxl_device_disk *disk, char *buf2)
                     return 0;
                 }
                 tok = p + 1;
+            } else if (*p == ',') {
+                state = DSTATE_VIRTPATH;
+                disk->phystype = PHYSTYPE_EMPTY;
+                disk->physpath = strdup("");
+                tok = p + 1;
             }
             break;
         case DSTATE_TAP:
@@ -1834,8 +1839,8 @@ static void cd_insert(const char *dom, const char *virtdev, char *phys)
             libxl_string_to_phystype(&ctx, phys, &disk.phystype);
         }
     } else {
-            disk.physpath = NULL;
-            disk.phystype = 0;
+            disk.physpath = strdup("");
+            disk.phystype = PHYSTYPE_EMPTY;
     }
     disk.virtpath = (char*)virtdev;
     disk.unpluggable = 1;