From 682d0459c35d9a3616a6a5dfc03ac39d0dfe9e56 Mon Sep 17 00:00:00 2001 From: George Dunlap Date: Fri, 17 Jan 2020 14:01:05 +0000 Subject: [PATCH] golang/xenlight: Don't leak memory on context open failure If libxl_ctx_alloc() returns an error, we need to destroy the logger that we made. Restructure the Close() method such that it checks for each resource to be freed and then frees it. This allows Close() to be come idempotent, as well as to be a useful clean-up to a partially-created context. Signed-off-by: George Dunlap Reviewed-by: Nick Rosbrook --- tools/golang/xenlight/xenlight.go | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) diff --git a/tools/golang/xenlight/xenlight.go b/tools/golang/xenlight/xenlight.go index aa1e63a61a..3f1b0baa0c 100644 --- a/tools/golang/xenlight/xenlight.go +++ b/tools/golang/xenlight/xenlight.go @@ -79,28 +79,40 @@ type Context struct { } // NewContext returns a new Context. -func NewContext() (*Context, error) { - var ctx Context +func NewContext() (ctx *Context, err error) { + ctx = &Context{} + + defer func() { + if err != nil { + ctx.Close() + ctx = nil + } + }() ctx.logger = C.xtl_createlogger_stdiostream(C.stderr, C.XTL_ERROR, 0) ret := C.libxl_ctx_alloc(&ctx.ctx, C.LIBXL_VERSION, 0, (*C.xentoollog_logger)(unsafe.Pointer(ctx.logger))) if ret != 0 { - return nil, Error(ret) + return ctx, Error(ret) } - return &ctx, nil + return ctx, nil } // Close closes the Context. func (ctx *Context) Close() error { - ret := C.libxl_ctx_free(ctx.ctx) - ctx.ctx = nil - C.xtl_logger_destroy((*C.xentoollog_logger)(unsafe.Pointer(ctx.logger))) + if ctx.ctx != nil { + ret := C.libxl_ctx_free(ctx.ctx) + if ret != 0 { + return Error(ret) + } + ctx.ctx = nil + } - if ret != 0 { - return Error(ret) + if ctx.logger != nil { + C.xtl_logger_destroy((*C.xentoollog_logger)(unsafe.Pointer(ctx.logger))) + ctx.logger = nil } return nil -- 2.39.5