[PATCH v4 21/23] util: add support for formatting a program name in messages

["Daniel P. Berrangé" <berrange@redhat.com>]

The error_report function can include the program name in any
messages it prints. The qemu_log function has no equivalent
behaviour.

This introduces support for a "program name" in the new
messages API, which will be included by default for all
binaries.

This change tweaks the output of the error_report function,
adding a space between the program name and the location
info. The qemu_log function will gain the program name. This
can be easily seen with the 'log' trace backend, and how it
is now more closely matching error_report output.

Before:

  # qemu-system-x86_64 -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
  qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x5584e13937f0 dir=fish
  qcrypto_tls_creds_get_path TLS creds path creds=0x5584e13937f0 filename=ca-cert.pem path=<none>
  qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory

After:

  # qemu-system-x86_64 -object tls-creds-x509,id=t0,dir=fish -d 'trace:qcrypto*'
  qemu-system-x86_64: qcrypto_tls_creds_x509_load TLS creds x509 load creds=0x5584e13937f0 dir=fish
  qemu-system-x86_64: qcrypto_tls_creds_get_path TLS creds path creds=0x5584e13937f0 filename=ca-cert.pem path=<none>
  qemu-system-x86_64: Unable to access credentials fish/ca-cert.pem: No such file or directory

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 include/qemu/message.h         | 1 +
 system/vl.c                    | 2 +-
 tests/unit/test-error-report.c | 5 +++--
 util/error-report.c            | 4 ----
 util/message.c                 | 9 ++++++++-
 5 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/include/qemu/message.h b/include/qemu/message.h
index cfc3c92648..b8518d06be 100644
--- a/include/qemu/message.h
+++ b/include/qemu/message.h
@@ -6,6 +6,7 @@
 enum QMessageFormatFlags {
     QMESSAGE_FORMAT_TIMESTAMP = (1 << 0),
     QMESSAGE_FORMAT_WORKLOAD_NAME = (1 << 1),
+    QMESSAGE_FORMAT_PROGRAM_NAME = (1 << 2),
 };
 
 /**
diff --git a/system/vl.c b/system/vl.c
index 56829880f6..0ac1b11caf 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -815,7 +815,7 @@ static void realtime_init(void)
 
 static void configure_msg(QemuOpts *opts)
 {
-    int flags = 0;
+    int flags = QMESSAGE_FORMAT_PROGRAM_NAME;
     if (qemu_opt_get_bool(opts, "timestamp", false)) {
         flags |= QMESSAGE_FORMAT_TIMESTAMP;
     }
diff --git a/tests/unit/test-error-report.c b/tests/unit/test-error-report.c
index 78f8b57660..3987a8ed25 100644
--- a/tests/unit/test-error-report.c
+++ b/tests/unit/test-error-report.c
@@ -48,7 +48,7 @@ test_error_report_loc(void)
     g_test_trap_subprocess(NULL, 0, 0);
     g_test_trap_assert_passed();
     g_test_trap_assert_stderr("\
-test-error-report:some-file.c:7717: test error1*\
+test-error-report: some-file.c:7717: test error1*\
 test-error-report: test error2*\
 ");
 }
@@ -91,7 +91,8 @@ static void
 test_error_report_timestamp(void)
 {
     if (g_test_subprocess()) {
-        qmessage_set_format(QMESSAGE_FORMAT_TIMESTAMP);
+        qmessage_set_format(QMESSAGE_FORMAT_TIMESTAMP |
+                            QMESSAGE_FORMAT_PROGRAM_NAME);
         warn_report("warn");
         error_report("err");
         return;
diff --git a/util/error-report.c b/util/error-report.c
index edb04585aa..b010f97bda 100644
--- a/util/error-report.c
+++ b/util/error-report.c
@@ -176,10 +176,6 @@ static void print_loc(Monitor *cur)
     int i;
     const char *const *argp;
 
-    if (!cur && g_get_prgname()) {
-        error_printf_mon(NULL, "%s:", g_get_prgname());
-        sep = " ";
-    }
     switch (cur_loc->kind) {
     case LOC_CMDLINE:
         argp = cur_loc->ptr;
diff --git a/util/message.c b/util/message.c
index a91c008e08..1db9254733 100644
--- a/util/message.c
+++ b/util/message.c
@@ -5,7 +5,7 @@
 #include "qemu/message.h"
 #include "monitor/monitor.h"
 
-static int message_format;
+static int message_format = QMESSAGE_FORMAT_PROGRAM_NAME;
 static char *message_workloadname;
 
 void qmessage_set_format(int flags)
@@ -30,4 +30,11 @@ void qmessage_context_print(FILE *fp)
         message_workloadname) {
         fprintf(fp, "%s ", message_workloadname);
     }
+
+    if (message_format & QMESSAGE_FORMAT_PROGRAM_NAME) {
+        const char *pgnamestr = g_get_prgname();
+        if (pgnamestr) {
+            fprintf(fp, "%s: ", pgnamestr);
+        }
+    }
 }
-- 
2.50.1