[Qemu-devel] [PATCH V8 3/8] util: add error_append()

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 include/qapi/error.h |    6 ++++++
 util/error.c         |   21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 0 deletions(-)

diff --git a/include/qapi/error.h b/include/qapi/error.h
index 7d4c696..bcfb724 100644
--- a/include/qapi/error.h
+++ b/include/qapi/error.h
@@ -30,6 +30,12 @@ typedef struct Error Error;
 void error_set(Error **err, ErrorClass err_class, const char *fmt, ...) GCC_FMT_ATTR(3, 4);
 
 /**
+ * Append message to err if err != NULL && *err != NULL. "\n" will be inserted
+ * after old message.
+ */
+void error_append(Error **err, const char *fmt, ...) GCC_FMT_ATTR(2, 3);
+
+/**
  * Set an indirect pointer to an error given a ErrorClass value and a
  * printf-style human message, followed by a strerror() string if
  * @os_error is not zero.
diff --git a/util/error.c b/util/error.c
index 3ee362a..64bbb2d 100644
--- a/util/error.c
+++ b/util/error.c
@@ -46,6 +46,27 @@ void error_set(Error **errp, ErrorClass err_class, const char *fmt, ...)
     errno = saved_errno;
 }
 
+void error_append(Error **err, const char *fmt, ...)
+{
+    va_list ap;
+    gchar *msg, *msg_old;
+
+    if (!err || !*err) {
+        return;
+    }
+
+    va_start(ap, fmt);
+    msg = g_strdup_vprintf(fmt, ap);
+    va_end(ap);
+
+    msg_old = (*err)->msg;
+    (*err)->msg = g_strdup_printf("%s\n%s", msg_old, msg);
+
+    g_free(msg);
+    g_free(msg_old);
+
+}
+
 void error_set_errno(Error **errp, int os_errno, ErrorClass err_class,
                      const char *fmt, ...)
 {
-- 
1.7.1