[Qemu-devel] [PULL 1/1] error: ensure errno detail is printed with error_abort

[Markus Armbruster <armbru@redhat.com>]

From: "Daniel P. Berrange" <berrange@redhat.com>

When &error_abort is passed in, the error reporting code
will print the current error message and then abort() the
process. Unfortunately at the time it aborts, we've not
yet appended the errno detail. This makes debugging certain
problems significantly harder as the log is incomplete.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-Id: <1457544504-8548-22-git-send-email-berrange@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
---
 util/error.c | 42 ++++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 22 deletions(-)

diff --git a/util/error.c b/util/error.c
index 471b8b3..47f93af 100644
--- a/util/error.c
+++ b/util/error.c
@@ -44,7 +44,8 @@ static void error_handle_fatal(Error **errp, Error *err)
 
 static void error_setv(Error **errp,
                        const char *src, int line, const char *func,
-                       ErrorClass err_class, const char *fmt, va_list ap)
+                       ErrorClass err_class, const char *fmt, va_list ap,
+                       const char *suffix)
 {
     Error *err;
     int saved_errno = errno;
@@ -56,6 +57,11 @@ static void error_setv(Error **errp,
 
     err = g_malloc0(sizeof(*err));
     err->msg = g_strdup_vprintf(fmt, ap);
+    if (suffix) {
+        char *msg = err->msg;
+        err->msg = g_strdup_printf("%s: %s", msg, suffix);
+        g_free(msg);
+    }
     err->err_class = err_class;
     err->src = src;
     err->line = line;
@@ -74,7 +80,7 @@ void error_set_internal(Error **errp,
     va_list ap;
 
     va_start(ap, fmt);
-    error_setv(errp, src, line, func, err_class, fmt, ap);
+    error_setv(errp, src, line, func, err_class, fmt, ap, NULL);
     va_end(ap);
 }
 
@@ -85,7 +91,7 @@ void error_setg_internal(Error **errp,
     va_list ap;
 
     va_start(ap, fmt);
-    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap, NULL);
     va_end(ap);
 }
 
@@ -94,7 +100,6 @@ void error_setg_errno_internal(Error **errp,
                                int os_errno, const char *fmt, ...)
 {
     va_list ap;
-    char *msg;
     int saved_errno = errno;
 
     if (errp == NULL) {
@@ -102,15 +107,10 @@ void error_setg_errno_internal(Error **errp,
     }
 
     va_start(ap, fmt);
-    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap,
+               os_errno != 0 ? strerror(os_errno) : NULL);
     va_end(ap);
 
-    if (os_errno != 0) {
-        msg = (*errp)->msg;
-        (*errp)->msg = g_strdup_printf("%s: %s", msg, strerror(os_errno));
-        g_free(msg);
-    }
-
     errno = saved_errno;
 }
 
@@ -174,24 +174,22 @@ void error_setg_win32_internal(Error **errp,
                                int win32_err, const char *fmt, ...)
 {
     va_list ap;
-    char *msg1, *msg2;
+    char *suffix = NULL;
 
     if (errp == NULL) {
         return;
     }
 
-    va_start(ap, fmt);
-    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR, fmt, ap);
-    va_end(ap);
-
     if (win32_err != 0) {
-        msg1 = (*errp)->msg;
-        msg2 = g_win32_error_message(win32_err);
-        (*errp)->msg = g_strdup_printf("%s: %s (error: %x)", msg1, msg2,
-                                       (unsigned)win32_err);
-        g_free(msg2);
-        g_free(msg1);
+        suffix = g_win32_error_message(win32_err);
     }
+
+    va_start(ap, fmt);
+    error_setv(errp, src, line, func, ERROR_CLASS_GENERIC_ERROR,
+               fmt, ap, suffix);
+    va_end(ap);
+
+    g_free(suffix);
 }
 
 #endif
-- 
2.4.3