[Qemu-devel] [PATCH 12/14] trace: Add trace file name command-line option

[Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>]

From: Prerna Saxena <prerna@linux.vnet.ibm.com>

This patch adds an optional command line switch '-trace' to specify the
filename to write traces to, when qemu starts.
Eg, If compiled with the 'simple' trace backend,
[temp@system]$ qemu -trace FILENAME IMAGE
Allows the binary traces to be written to FILENAME instead of the option
set at config-time.

Signed-off-by: Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 qemu-options.hx |   11 +++++++++++
 vl.c            |   18 ++++++++++++++++++
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index db86feb..a0c091f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2234,6 +2234,17 @@ Normally QEMU loads a configuration file from @var{sysconfdir}/qemu.conf and
 @var{sysconfdir}/target-@var{ARCH}.conf on startup.  The @code{-nodefconfig}
 option will prevent QEMU from loading these configuration files at startup.
 ETEXI
+#ifdef CONFIG_SIMPLE_TRACE
+DEF("trace", HAS_ARG, QEMU_OPTION_trace,
+    "-trace\n"
+    "                Specify a trace file to log traces to\n",
+    QEMU_ARCH_ALL)
+STEXI
+@item -trace
+@findex -trace
+Specify a trace file to log output traces to.
+ETEXI
+#endif
 
 HXCOMM This is the last statement. Insert new options before this line!
 STEXI
diff --git a/vl.c b/vl.c
index b3e3676..99664e9 100644
--- a/vl.c
+++ b/vl.c
@@ -47,6 +47,10 @@
 #include <dirent.h>
 #include <netdb.h>
 #include <sys/select.h>
+#ifdef CONFIG_SIMPLE_TRACE
+#include "trace.h"
+#endif
+
 #ifdef CONFIG_BSD
 #include <sys/stat.h>
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__DragonFly__)
@@ -1821,6 +1825,9 @@ int main(int argc, char **argv, char **envp)
     int show_vnc_port = 0;
     int defconfig = 1;
 
+#ifdef CONFIG_SIMPLE_TRACE
+    const char *trace_file = NULL;
+#endif
     atexit(qemu_run_exit_notifiers);
     error_set_progname(argv[0]);
 
@@ -2590,6 +2597,11 @@ int main(int argc, char **argv, char **envp)
                 }
                 xen_mode = XEN_ATTACH;
                 break;
+#ifdef CONFIG_SIMPLE_TRACE
+            case QEMU_OPTION_trace:
+                trace_file = optarg;
+                break;
+#endif
             case QEMU_OPTION_readconfig:
                 {
                     int ret = qemu_read_config_file(optarg);
@@ -2633,6 +2645,12 @@ int main(int argc, char **argv, char **envp)
         data_dir = CONFIG_QEMU_DATADIR;
     }
 
+#ifdef CONFIG_SIMPLE_TRACE
+    /*
+     * Set the trace file name, if specified.
+     */
+    st_set_trace_file(trace_file);
+#endif
     /*
      * Default to max_cpus = smp_cpus, in case the user doesn't
      * specify a max_cpus value.
-- 
1.7.1