From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39822) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1acLyW-0008Pq-RQ for qemu-devel@nongnu.org; Sat, 05 Mar 2016 18:51:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1acLyT-0005kk-QF for qemu-devel@nongnu.org; Sat, 05 Mar 2016 18:51:08 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42314) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1acLyT-0005kQ-Kk for qemu-devel@nongnu.org; Sat, 05 Mar 2016 18:51:05 -0500 From: Eric Blake Date: Sat, 5 Mar 2016 16:50:45 -0700 Message-Id: <1457221861-18067-3-git-send-email-eblake@redhat.com> In-Reply-To: <1457221861-18067-1-git-send-email-eblake@redhat.com> References: <1457221861-18067-1-git-send-email-eblake@redhat.com> Subject: [Qemu-devel] [PATCH v13 02/18] qapi: Guarantee NULL obj on input visitor callback error List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: armbru@redhat.com, Michael Roth Our existing input visitors were not very consistent on errors in a function taking 'TYPE **obj'. While all of them set '*obj' to allocated storage on success, it was not obvious whether '*obj' was guaranteed safe on failure, or whether it was left uninitialized. But a future patch wants to guarantee that visit_type_FOO() does not leak a partially-constructed obj back to the caller; it is easier to implement this if we can reliably state that '*obj' is assigned on exit, even on failures. The opts-visitor start_struct() doesn't set an error, but it also was doing a weird check for 0 size; all callers pass in non-zero size if obj is non-NULL. Signed-off-by: Eric Blake --- v13: no change v12: new patch --- qapi/opts-visitor.c | 3 ++- qapi/qmp-input-visitor.c | 4 ++++ qapi/string-input-visitor.c | 1 + 3 files changed, 7 insertions(+), 1 deletion(-) diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c index f9a2346..fd90608 100644 --- a/qapi/opts-visitor.c +++ b/qapi/opts-visitor.c @@ -132,7 +132,7 @@ opts_start_struct(Visitor *v, const char *name, void **obj, const QemuOpt *opt; if (obj) { - *obj = g_malloc0(size > 0 ? size : 1); + *obj = g_malloc0(size); } if (ov->depth++ > 0) { return; @@ -313,6 +313,7 @@ opts_type_str(Visitor *v, const char *name, char **obj, Error **errp) opt = lookup_scalar(ov, name, errp); if (!opt) { + *obj = NULL; return; } *obj = g_strdup(opt->str ? opt->str : ""); diff --git a/qapi/qmp-input-visitor.c b/qapi/qmp-input-visitor.c index 03dcb65..550aed6 100644 --- a/qapi/qmp-input-visitor.c +++ b/qapi/qmp-input-visitor.c @@ -119,6 +119,9 @@ static void qmp_input_start_struct(Visitor *v, const char *name, void **obj, QObject *qobj = qmp_input_get_object(qiv, name, true); Error *err = NULL; + if (obj) { + *obj = NULL; + } if (!qobj || qobject_type(qobj) != QTYPE_QDICT) { error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "QDict"); @@ -266,6 +269,7 @@ static void qmp_input_type_str(Visitor *v, const char *name, char **obj, QString *qstr = qobject_to_qstring(qmp_input_get_object(qiv, name, true)); if (!qstr) { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); return; diff --git a/qapi/string-input-visitor.c b/qapi/string-input-visitor.c index d591e67..4087bf9 100644 --- a/qapi/string-input-visitor.c +++ b/qapi/string-input-visitor.c @@ -292,6 +292,7 @@ static void parse_type_str(Visitor *v, const char *name, char **obj, if (siv->string) { *obj = g_strdup(siv->string); } else { + *obj = NULL; error_setg(errp, QERR_INVALID_PARAMETER_TYPE, name ? name : "null", "string"); } -- 2.5.0