[PATCHv2 1/2] util/qemu-error: add guest name helper with -msg options

[Mario Smarduch <msmarduch@digitalocean.com>]

This patch adds an option to enable/disable printing lead guest name in
logging messages.

A '-msg name=on|off' allows to turn on, off guest name logging.

If guest name is not set disabling this makes sense.

Verified with all combinations of 
  '-msg timestamp=yes|no,name=yes|no.

Signed-off-by: Mario Smarduch <msmarduch@digitalocean.com>
---
 include/qemu/error-report.h |  1 +
 qemu-options.hx             | 10 ++++++----
 util/qemu-error.c           | 31 +++++++++++++++++++++++++++++++
 vl.c                        |  5 +++++
 4 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
index 00d069b..9b44a06 100644
--- a/include/qemu/error-report.h
+++ b/include/qemu/error-report.h
@@ -74,5 +74,6 @@ void error_init(const char *argv0);
 
 const char *error_get_progname(void);
 extern bool enable_timestamp_msg;
+extern bool enable_guestname_msg;
 
 #endif
diff --git a/qemu-options.hx b/qemu-options.hx
index 2a04ca6..6066001 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4164,14 +4164,16 @@ HXCOMM Deprecated by -accel tcg
 DEF("no-kvm", 0, QEMU_OPTION_no_kvm, "", QEMU_ARCH_I386)
 
 DEF("msg", HAS_ARG, QEMU_OPTION_msg,
-    "-msg timestamp[=on|off]\n"
+    "-msg [timestamp=on|off][name=on|off]\n"
     "                change the format of messages\n"
-    "                on|off controls leading timestamps (default:on)\n",
+    "                timestamp=on|off controls leading timestamps (default: on)\n"
+    "                name=on|off controls leading guest name (default: off)\n",
     QEMU_ARCH_ALL)
 STEXI
-@item -msg timestamp[=on|off]
+@item -msg timestamp=on|off
+@item -msg name=on|off
 @findex -msg
-prepend a timestamp to each log message.(default:on)
+Prepend additional information to each log message
 ETEXI
 
 DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate,
diff --git a/util/qemu-error.c b/util/qemu-error.c
index f373f3b..8ece7b2 100644
--- a/util/qemu-error.c
+++ b/util/qemu-error.c
@@ -11,6 +11,8 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/option.h"
+#include "qemu/config-file.h"
 #include "monitor/monitor.h"
 #include "qemu/error-report.h"
 
@@ -192,6 +194,8 @@ static void print_loc(void)
 }
 
 bool enable_timestamp_msg;
+bool enable_guestname_msg;
+
 /*
  * Print a message to current monitor if we have one, else to stderr.
  * @report_type is the type of message: error, warning or informational.
@@ -228,6 +232,27 @@ static void vreport(report_type type, const char *fmt, va_list ap)
     error_printf("\n");
 }
 
+static const char *error_get_guestname(void)
+{
+    QemuOpts *opts = qemu_opts_find(qemu_find_opts("name"), NULL);
+    return qemu_opt_get(opts, "guest");
+}
+
+/*
+ * Also print the guest name, handy if we log to a server.
+ */
+static void error_print_guestname(void)
+{
+    const char *name;
+
+    if (enable_guestname_msg) {
+        name = error_get_guestname();
+        if (name && !cur_mon) {
+            error_printf("Guest [%s] ", name);
+        }
+    }
+}
+
 /*
  * Print an error message to current monitor if we have one, else to stderr.
  * Format arguments like vsprintf().  The resulting message should be
@@ -237,6 +262,7 @@ static void vreport(report_type type, const char *fmt, va_list ap)
  */
 void error_vreport(const char *fmt, va_list ap)
 {
+    error_print_guestname();
     vreport(REPORT_TYPE_ERROR, fmt, ap);
 }
 
@@ -248,6 +274,7 @@ void error_vreport(const char *fmt, va_list ap)
  */
 void warn_vreport(const char *fmt, va_list ap)
 {
+    error_print_guestname();
     vreport(REPORT_TYPE_WARNING, fmt, ap);
 }
 
@@ -274,6 +301,7 @@ void error_report(const char *fmt, ...)
 {
     va_list ap;
 
+    error_print_guestname();
     va_start(ap, fmt);
     vreport(REPORT_TYPE_ERROR, fmt, ap);
     va_end(ap);
@@ -289,6 +317,7 @@ void warn_report(const char *fmt, ...)
 {
     va_list ap;
 
+    error_print_guestname();
     va_start(ap, fmt);
     vreport(REPORT_TYPE_WARNING, fmt, ap);
     va_end(ap);
@@ -324,6 +353,7 @@ bool error_report_once_cond(bool *printed, const char *fmt, ...)
         return false;
     }
     *printed = true;
+    error_print_guestname();
     va_start(ap, fmt);
     vreport(REPORT_TYPE_ERROR, fmt, ap);
     va_end(ap);
@@ -344,6 +374,7 @@ bool warn_report_once_cond(bool *printed, const char *fmt, ...)
         return false;
     }
     *printed = true;
+    error_print_guestname();
     va_start(ap, fmt);
     vreport(REPORT_TYPE_WARNING, fmt, ap);
     va_end(ap);
diff --git a/vl.c b/vl.c
index 002bf49..024bdc6 100644
--- a/vl.c
+++ b/vl.c
@@ -417,6 +417,10 @@ static QemuOptsList qemu_msg_opts = {
             .name = "timestamp",
             .type = QEMU_OPT_BOOL,
         },
+        {
+            .name = "name",
+            .type = QEMU_OPT_BOOL,
+        },
         { /* end of list */ }
     },
 };
@@ -1263,6 +1267,7 @@ static void realtime_init(void)
 static void configure_msg(QemuOpts *opts)
 {
     enable_timestamp_msg = qemu_opt_get_bool(opts, "timestamp", true);
+    enable_guestname_msg = qemu_opt_get_bool(opts, "name", false);
 }
 
 
-- 
2.9.3