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

[Anthony Liguori <anthony@codemonkey.ws>]

On 08/12/2010 05:36 AM, Stefan Hajnoczi wrote:
> 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
>    

You'll save yourself some future headaches by using a QemuOptsList to 
start out with.

Regards,

Anthony Liguori

>               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.
>