Re: [Qemu-block] [PATCH 4/6] trace: enable tracing in qemu-nbd

[Eric Blake]

On 06/13/2016 10:58 AM, Denis V. Lunev wrote:
> Please note, trace_init_backends() must be called in the final process,
> i.e. after daemonization. This is necessary to keep tracing thread in
> the proper process.
> 
> Signed-off-by: Denis V. Lunev 
> CC: Eric Blake 
> CC: Paolo Bonzini 
> CC: Stefan Hajnoczi 
> CC: Kevin Wolf 
> ---
>  Makefile  |  2 +-
>  qemu-nbd.c| 18 +-
>  qemu-nbd.texi |  2 ++
>  3 files changed, 20 insertions(+), 2 deletions(-)
> 

> +++ b/qemu-nbd.c

> @@ -88,6 +90,8 @@ static void usage(const char *name)
>  "General purpose options:\n"
>  "  --object type,id=ID,...   define an object such as 'secret' for 
> providing\n"
>  "passwords and/or encryption keys\n"
> +"  -T, --trace [[enable=]][,events=][,file=]\n"
> +"specify tracing options\n"

> +++ b/qemu-nbd.texi
> @@ -92,6 +92,8 @@ Display extra debugging information
>  Display this help and exit
>  @item -V, --version
>  Display version information and exit
> +@item -T, --trace [events=@var{file}][,file=@var{file}]

Still not consistent.

-- 
Eric Blake   eblake redhat com+1-919-301-3266
Libvirt virtualization library http://libvirt.org



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[Qemu-block] [PATCH 4/6] trace: enable tracing in qemu-nbd

[Denis V. Lunev]

Please note, trace_init_backends() must be called in the final process,
i.e. after daemonization. This is necessary to keep tracing thread in
the proper process.

Signed-off-by: Denis V. Lunev 
CC: Eric Blake 
CC: Paolo Bonzini 
CC: Stefan Hajnoczi 
CC: Kevin Wolf 
---
 Makefile  |  2 +-
 qemu-nbd.c| 18 +-
 qemu-nbd.texi |  2 ++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index e432e08..49b9650 100644
--- a/Makefile
+++ b/Makefile
@@ -558,7 +558,7 @@ fsdev/virtfs-proxy-helper.1: fsdev/virtfs-proxy-helper.texi
  $(POD2MAN) --section=1 --center=" " --release=" " 
fsdev/virtfs-proxy-helper.pod > $@, \
  "  GEN   $@")
 
-qemu-nbd.8: qemu-nbd.texi
+qemu-nbd.8: qemu-nbd.texi qemu-option-trace.texi
$(call quiet-command, \
  perl -Ww -- $(SRC_PATH)/scripts/texi2pod.pl $< qemu-nbd.pod && \
  $(POD2MAN) --section=8 --center=" " --release=" " qemu-nbd.pod > $@, \
diff --git a/qemu-nbd.c b/qemu-nbd.c
index 6554f0a..f92820f 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -27,12 +27,14 @@
 #include "qemu/error-report.h"
 #include "qemu/config-file.h"
 #include "qemu/bswap.h"
+#include "qemu/log.h"
 #include "block/snapshot.h"
 #include "qapi/util.h"
 #include "qapi/qmp/qstring.h"
 #include "qom/object_interfaces.h"
 #include "io/channel-socket.h"
 #include "crypto/init.h"
+#include "trace/control.h"
 
 #include 
 #include 
@@ -88,6 +90,8 @@ static void usage(const char *name)
 "General purpose options:\n"
 "  --object type,id=ID,...   define an object such as 'secret' for providing\n"
 "passwords and/or encryption keys\n"
+"  -T, --trace [[enable=]][,events=][,file=]\n"
+"specify tracing options\n"
 #ifdef __linux__
 "Kernel NBD client support:\n"
 "  -c, --connect=DEV connect FILE to the local NBD device DEV\n"
@@ -470,7 +474,7 @@ int main(int argc, char **argv)
 off_t fd_size;
 QemuOpts *sn_opts = NULL;
 const char *sn_id_or_name = NULL;
-const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:";
+const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:tl:x:T:";
 struct option lopt[] = {
 { "help", no_argument, NULL, 'h' },
 { "version", no_argument, NULL, 'V' },
@@ -498,6 +502,7 @@ int main(int argc, char **argv)
 { "export-name", required_argument, NULL, 'x' },
 { "tls-creds", required_argument, NULL, QEMU_NBD_OPT_TLSCREDS },
 { "image-opts", no_argument, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
+{ "trace", required_argument, NULL, 'T' },
 { NULL, 0, NULL, 0 }
 };
 int ch;
@@ -518,6 +523,7 @@ int main(int argc, char **argv)
 const char *tlscredsid = NULL;
 bool imageOpts = false;
 bool writethrough = true;
+char *trace_file = NULL;
 
 /* The client thread uses SIGTERM to interrupt the server.  A signal
  * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -531,6 +537,7 @@ int main(int argc, char **argv)
 
 module_call_init(MODULE_INIT_QOM);
 qemu_add_opts(_object_opts);
+qemu_add_opts(_trace_opts);
 qemu_init_exec_dir(argv[0]);
 
 while ((ch = getopt_long(argc, argv, sopt, lopt, _ind)) != -1) {
@@ -703,6 +710,9 @@ int main(int argc, char **argv)
 case QEMU_NBD_OPT_IMAGE_OPTS:
 imageOpts = true;
 break;
+case 'T':
+trace_file = trace_opt_parse(optarg, trace_file);
+break;
 }
 }
 
@@ -718,6 +728,12 @@ int main(int argc, char **argv)
 exit(EXIT_FAILURE);
 }
 
+if (!trace_init_backends()) {
+exit(1);
+}
+trace_init_file(trace_file);
+qemu_set_log(LOG_TRACE);
+
 if (tlscredsid) {
 if (sockpath) {
 error_report("TLS is only supported with IPv4/IPv6");
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 9f23343..1c59c41 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -92,6 +92,8 @@ Display extra debugging information
 Display this help and exit
 @item -V, --version
 Display version information and exit
+@item -T, --trace [events=@var{file}][,file=@var{file}]
+@include qemu-option-trace.texi
 @end table
 
 @c man end
-- 
2.5.0