From 3146a8a802232659e3264c6b67b0c4195b8c237e Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Fri, 28 Jan 2011 16:54:13 +0000 Subject: [PATCH] libxl: when using pygrub, do not segfault if no blktap Running xl create configfile where configfile includes the lines bootloader = "/usr/bin/pygrub" disk = [ 'file:/dev/mapper/vg0-partname,xvda1,w' ] then xl segfaults at the line ret = strdup(dev); of libxl_device_disk_local_attach() in tools/libxl/libxl.c . The problem is that dev is not set if libxl__blktap_enabled(&gc) is false or if phystype isn't recognized. In the latter case we want to skip that line and return NULL, but if libxl__blktap_enabled(&gc) is false we should be returning something, at least in the cases where the device has a name in the host which we can just refer to. Also improve the error message when QCOW or QCOW2 are specified, and avoid using an uninitialised value of "ret". Signed-off-by: M A Young Signed-off-by: Stefano Stabellini Committed-by: Ian Jackson --- tools/libxl/libxl.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c index ccbc84218b..9658d6714e 100644 --- a/tools/libxl/libxl.c +++ b/tools/libxl/libxl.c @@ -1021,7 +1021,7 @@ char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk) { libxl__gc gc = LIBXL_INIT_GC(ctx); const char *dev = NULL; - char *ret; + char *ret = NULL; int phystype = disk->phystype; switch (phystype) { case PHYSTYPE_PHY: { @@ -1033,18 +1033,27 @@ char * libxl_device_disk_local_attach(libxl_ctx *ctx, libxl_device_disk *disk) /* let's pretend is tap:aio for the moment */ phystype = PHYSTYPE_AIO; case PHYSTYPE_AIO: - case PHYSTYPE_QCOW: - case PHYSTYPE_QCOW2: + if (!libxl__blktap_enabled(&gc)) { + dev = disk->physpath; + break; + } case PHYSTYPE_VHD: if (libxl__blktap_enabled(&gc)) dev = libxl__blktap_devpath(&gc, disk->physpath, phystype); + else + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "tapdisk2 is required to open a vhd disk\n"); + break; + case PHYSTYPE_QCOW: + case PHYSTYPE_QCOW2: + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "cannot locally attach a qcow or qcow2 disk image\n"); break; default: LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "unrecognized disk physical type: %d\n", phystype); break; } - ret = strdup(dev); + if (dev != NULL) + ret = strdup(dev); libxl__free_all(&gc); return ret; } -- 2.30.2