From: Ian Jackson Date: Wed, 27 Apr 2016 15:34:19 +0000 (+0100) Subject: libxl: Provide libxl__backendpath_parse_domid X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~1065 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=481dddb63b1fac2368c8e8be109babee0b1ca171;p=xen.git libxl: Provide libxl__backendpath_parse_domid Multiple places in libxl need to figure out the backend domid of a device. This can be discovered easily by looking at the backend path, which always starts /local/domain/$backend_domid/. There are no call sites yet. This is part of XSA-175. Signed-off-by: Ian Jackson Reviewed-by: Wei Liu --- diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c index b4bd005b4f..9f115c628c 100644 --- a/tools/libxl/libxl_device.c +++ b/tools/libxl/libxl_device.c @@ -298,6 +298,21 @@ static int disk_try_backend(disk_try_backend_args *a, return 0; } +int libxl__backendpath_parse_domid(libxl__gc *gc, const char *be_path, + libxl_domid *domid_out) { + int r; + unsigned int domid_sc; + char delim_sc; + + r = sscanf(be_path, "/local/domain/%u%c", &domid_sc, &delim_sc); + if (!(r==2 && delim_sc=='/')) { + LOG(ERROR, "internal error: backend path %s unparseable!", be_path); + return ERROR_FAIL; + } + *domid_out = domid_sc; + return 0; +} + int libxl__device_disk_set_backend(libxl__gc *gc, libxl_device_disk *disk) { libxl_disk_backend ok; disk_try_backend_args a; diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h index a4a461330f..d8b877b8a4 100644 --- a/tools/libxl/libxl_internal.h +++ b/tools/libxl/libxl_internal.h @@ -702,6 +702,8 @@ _hidden char **libxl__xs_directory(libxl__gc *gc, xs_transaction_t t, /* On error: returns NULL, sets errno (no logging) */ _hidden char *libxl__xs_libxl_path(libxl__gc *gc, uint32_t domid); +_hidden int libxl__backendpath_parse_domid(libxl__gc *gc, const char *be_path, + libxl_domid *domid_out); /*----- "checked" xenstore access functions -----*/ /* Each of these functions will check that it succeeded; if it