Re: [Qemu-devel] [PATCH v6 2/2] log: Make glib logging go through QEMU

[Markus Armbruster <armbru@redhat.com>]

Christophe Fergeau <cfergeau@redhat.com> writes:

> This commit adds a qemu_init_logging() helper which calls
> g_log_set_default_handler() so that glib logs (g_log, g_warning, ...)
> are handled similarly to other QEMU logs. This means they will get a
> timestamp if timestamps are enabled, and they will go through the
> HMP monitor if one is configured.
> This commit also adds a call to qemu_init_logging() to the binaries
> installed by QEMU.
> glib debug messages are enabled through G_MESSAGES_DEBUG similarly to
> glib default log handler.
>
> At the moment, this change will mostly impact SPICE logging if your
> spice version is >= 0.14.1. With older spice versions, this is not going
> to work as expected, but will not have any ill effect, so this call is
> not conditional on the SPICE version.
>
> Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>
> ---
>  bsd-user/main.c             |  2 ++
>  include/qemu/error-report.h |  3 ++-
>  linux-user/main.c           |  2 ++
>  qemu-img.c                  |  2 +-
>  qemu-io.c                   |  2 +-
>  qemu-nbd.c                  |  2 +-
>  scsi/qemu-pr-helper.c       |  1 +
>  util/qemu-error.c           | 48 ++++++++++++++++++++++++++++++++++++-
>  vl.c                        |  2 +-
>  9 files changed, 58 insertions(+), 6 deletions(-)
>
> diff --git a/bsd-user/main.c b/bsd-user/main.c
> index 0d3156974c..8fd8ae4127 100644
> --- a/bsd-user/main.c
> +++ b/bsd-user/main.c
> @@ -24,6 +24,7 @@
>  #include "qapi/error.h"
>  #include "qemu.h"
>  #include "qemu/config-file.h"
> +#include "qemu/error-report.h"
>  #include "qemu/path.h"
>  #include "qemu/help_option.h"
>  #include "cpu.h"
> @@ -743,6 +744,7 @@ int main(int argc, char **argv)
>      if (argc <= 1)
>          usage();
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
>      qemu_init_cpu_list();
>      module_call_init(MODULE_INIT_QOM);

This changes output of error_report() & friends in this program.
Probably in a good way.  Should it be a separate commit?  If not, it
should at least be mentioned in the commit message.

> diff --git a/include/qemu/error-report.h b/include/qemu/error-report.h
> index 0a8d9cc9ea..ce43c02314 100644
> --- a/include/qemu/error-report.h
> +++ b/include/qemu/error-report.h
> @@ -34,7 +34,6 @@ void error_vprintf(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
>  void error_printf(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
>  void error_vprintf_unless_qmp(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
>  void error_printf_unless_qmp(const char *fmt, ...) GCC_FMT_ATTR(1, 2);
> -void error_set_progname(const char *argv0);
>  
>  void error_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
>  void warn_vreport(const char *fmt, va_list ap) GCC_FMT_ATTR(1, 0);
> @@ -49,6 +48,8 @@ bool error_report_once_cond(bool *printed, const char *fmt, ...)
>  bool warn_report_once_cond(bool *printed, const char *fmt, ...)
>      GCC_FMT_ATTR(2, 3);
>  
> +void error_init(const char *argv0);
> +
>  /*
>   * Similar to error_report(), except it prints the message just once.
>   * Return true when it prints, false otherwise.
> diff --git a/linux-user/main.c b/linux-user/main.c
> index a0aba9cb1e..f9efe9ff6e 100644
> --- a/linux-user/main.c
> +++ b/linux-user/main.c
> @@ -27,6 +27,7 @@
>  #include "qemu/path.h"
>  #include "qemu/config-file.h"
>  #include "qemu/cutils.h"
> +#include "qemu/error-report.h"
>  #include "qemu/help_option.h"
>  #include "cpu.h"
>  #include "exec/exec-all.h"
> @@ -600,6 +601,7 @@ int main(int argc, char **argv, char **envp)
>      int ret;
>      int execfd;
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
>      qemu_init_cpu_list();
>      module_call_init(MODULE_INIT_QOM);

Likewise.

> diff --git a/qemu-img.c b/qemu-img.c
> index ad04f59565..0af9cac244 100644
> --- a/qemu-img.c
> +++ b/qemu-img.c
> @@ -4912,8 +4912,8 @@ int main(int argc, char **argv)
>      signal(SIGPIPE, SIG_IGN);
>  #endif
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
> -    error_set_progname(argv[0]);
>      qemu_init_exec_dir(argv[0]);
>  
>      if (qemu_init_main_loop(&local_error)) {
> diff --git a/qemu-io.c b/qemu-io.c
> index 2c52ac0ade..8d5d5911cb 100644
> --- a/qemu-io.c
> +++ b/qemu-io.c
> @@ -522,8 +522,8 @@ int main(int argc, char **argv)
>      signal(SIGPIPE, SIG_IGN);
>  #endif
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
> -    error_set_progname(argv[0]);
>      qemu_init_exec_dir(argv[0]);
>  
>      qcrypto_init(&error_fatal);
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 1f7b2a03f5..39849f1692 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -685,8 +685,8 @@ int main(int argc, char **argv)
>      signal(SIGPIPE, SIG_IGN);
>  #endif
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
> -    error_set_progname(argv[0]);
>      qcrypto_init(&error_fatal);
>  
>      module_call_init(MODULE_INIT_QOM);
> diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
> index e7af637232..2541fbbd1b 100644
> --- a/scsi/qemu-pr-helper.c
> +++ b/scsi/qemu-pr-helper.c
> @@ -895,6 +895,7 @@ int main(int argc, char **argv)
>  
>      signal(SIGPIPE, SIG_IGN);
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
>      module_call_init(MODULE_INIT_QOM);
>      qemu_add_opts(&qemu_trace_opts);

Likewise.

> diff --git a/util/qemu-error.c b/util/qemu-error.c
> index fcbe8a1f74..2684870683 100644
> --- a/util/qemu-error.c
> +++ b/util/qemu-error.c
> @@ -142,7 +142,7 @@ static const char *progname;
>  /*
>   * Set the program name for error_print_loc().
>   */
> -void error_set_progname(const char *argv0)
> +static void error_set_progname(const char *argv0)
>  {
>      const char *p = strrchr(argv0, '/');
>      progname = p ? p + 1 : argv0;
> @@ -345,3 +345,49 @@ bool warn_report_once_cond(bool *printed, const char *fmt, ...)
>      va_end(ap);
>      return true;
>  }
> +
> +static char *qemu_glog_domains;
> +
> +static void qemu_log_func(const gchar *log_domain,
> +                          GLogLevelFlags log_level,
> +                          const gchar *message,
> +                          gpointer user_data)
> +{
> +    switch (log_level & G_LOG_LEVEL_MASK) {
> +    case G_LOG_LEVEL_DEBUG:
> +    case G_LOG_LEVEL_INFO:
> +        /* Use same G_MESSAGES_DEBUG logic as glib to enable/disable debug
> +         * messages */

Let's wing this comment.

> +        if (qemu_glog_domains == NULL) {
> +            break;
> +        }
> +        if (strcmp(qemu_glog_domains, "all") != 0 &&
> +          (log_domain == NULL || !strstr(qemu_glog_domains, log_domain))) {
> +            break;
> +        }
> +        /* Fall through */
> +    case G_LOG_LEVEL_MESSAGE:
> +        info_report("%s: %s", log_domain?:"", message);

Spaces around ?:, please.

If log_domain is null, the message will look like

    info: : MESSAGE text

which is ugly.  What about

           info_report("%s%s%s",
                       log_domain ? ": " : "", log_domain ?: "", message);

More of the same below.

> +        break;
> +    case G_LOG_LEVEL_WARNING:
> +        warn_report("%s: %s", log_domain?:"", message);
> +        break;
> +    case G_LOG_LEVEL_CRITICAL:
> +        /* Fall through */
> +    case G_LOG_LEVEL_ERROR:
> +        error_report("%s: %s", log_domain?:"", message);
> +        break;
> +    }
> +}
> +
> +void error_init(const char *argv0)
> +{
> +    /* Set the program name for error_print_loc(). */
> +    error_set_progname(argv0);
> +
> +    /* This sets up glib logging so libraries using it also print their logs
> +     * through error_report(), warn_report(), info_report(). */

Let's wing this comment.

> +    g_log_set_default_handler(qemu_log_func, NULL);
> +    g_warn_if_fail(qemu_glog_domains == NULL);
> +    qemu_glog_domains = g_strdup(g_getenv("G_MESSAGES_DEBUG"));
> +}
> diff --git a/vl.c b/vl.c
> index bc9fbec654..bfef38c3a3 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -3039,6 +3039,7 @@ int main(int argc, char **argv, char **envp)
>      QSIMPLEQ_HEAD(, BlockdevOptions_queue) bdo_queue
>          = QSIMPLEQ_HEAD_INITIALIZER(bdo_queue);
>  
> +    error_init(argv[0]);
>      module_call_init(MODULE_INIT_TRACE);
>  
>      qemu_init_cpu_list();
> @@ -3047,7 +3048,6 @@ int main(int argc, char **argv, char **envp)
>      qemu_mutex_lock_iothread();
>  
>      atexit(qemu_run_exit_notifiers);
> -    error_set_progname(argv[0]);
>      qemu_init_exec_dir(argv[0]);
>  
>      module_call_init(MODULE_INIT_QOM);

Almost ready.