Re: [Qemu-devel] [PATCH v4 08/20] instrument: [hmp] Add library loader

[Markus Armbruster]

Lluís Vilanova <address@hidden> writes:

> Signed-off-by: Lluís Vilanova <address@hidden>
> ---
>  hmp-commands.hx |   28 ++++++++++++++++++++++++++
>  monitor.c       |   60 
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 88 insertions(+)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index 1941e19932..703d7262f5 100644
> --- a/hmp-commands.hx
> +++ b/hmp-commands.hx
> @@ -1858,6 +1858,34 @@ ETEXI
>          .sub_table  = info_cmds,
>      },
>  
> +    {
> +        .name       = "instr-load",
> +        .args_type  = "path:F,args:s?",
> +        .params     = "path [arg]",
> +        .help       = "load an instrumentation library",
> +        .cmd        = hmp_instr_load,
> +    },
> +
> +STEXI
> address@hidden instr-load @var{path} [args=value[,...]]
> address@hidden instr-load
> +Load an instrumentation library.
> +ETEXI
> +
> +    {
> +        .name       = "instr-unload",
> +        .args_type  = "handle:i",
> +        .params     = "handle",
> +        .help       = "unload an instrumentation library",
> +        .cmd        = hmp_instr_unload,
> +    },
> +
> +STEXI
> address@hidden instr-unload
> address@hidden instr-unload
> +Unload an instrumentation library.
> +ETEXI
> +
>  STEXI
>  @end table
>  ETEXI

Want #ifdef CONFIG_INSTRUMENT, see my review of the previous patch.

See also my remark there on returning handles vs. passing in IDs.

> diff --git a/monitor.c b/monitor.c
> index e0f880107f..8a7684f860 100644
> --- a/monitor.c
> +++ b/monitor.c
> @@ -2319,6 +2319,66 @@ int monitor_fd_param(Monitor *mon, const char *fdname, 
> Error **errp)
>      return fd;
>  }
>  
> +static void hmp_instr_load(Monitor *mon, const QDict *qdict)
> +{
> +    const char *path = qdict_get_str(qdict, "path");
> +    const char *str = qdict_get_try_str(qdict, "args");
> +    strList args;

Blank line between last declaration and first statement, please.

> +    args.value = (str == NULL) ? NULL : (char *)str;

What's wrong with

       args.value = (char *)str;

?

> +    args.next = NULL;
> +    InstrLoadResult *res = qmp_instr_load(path, args.value != NULL,
> +                                          args.value != NULL ? &args : NULL,
> +                                          NULL);
> +    switch (res->code) {
> +    case INSTR_LOAD_CODE_OK:
> +        monitor_printf(mon, "Handle: %"PRId64"\n", res->handle);
> +        monitor_printf(mon, "OK\n");
> +        break;
> +    case INSTR_LOAD_CODE_TOO_MANY:
> +        monitor_printf(mon, "Too many instrumentation libraries already 
> loaded\n");
> +        break;
> +    case INSTR_LOAD_CODE_ERROR:
> +        monitor_printf(mon, "Instrumentation library returned a non-zero 
> value during initialization");
> +        break;
> +    case INSTR_LOAD_CODE_DLERROR:
> +        monitor_printf(mon, "Error loading library: %s\n", res->msg);
> +        break;
> +    case INSTR_LOAD_CODE_UNAVAILABLE:
> +        monitor_printf(mon, "Service not available\n");
> +        break;
> +    default:
> +        fprintf(stderr, "Unknown instrumentation load code: %d", res->code);
> +        exit(1);

Impossible conditions should be assertion failures, but it's a moot point
because...

> +        break;
> +    }
> +    qapi_free_InstrLoadResult(res);
> +}

With qmp_instr_load() fixed to set an error on failure, this becomes
something like

       InstrLoadResult *res = qmp_instr_load(path, args.value != NULL,
                                             args.value != NULL ? &args : NULL,
                                             &err);
       if (err) {
           error_report_err(err);
       } else {
           monitor_printf(mon, "Handle: %"PRId64"\n", res->handle);
           monitor_printf(mon, "OK\n");
       }
       qapi_free_InstrLoadResult(res);

> +
> +static void hmp_instr_unload(Monitor *mon, const QDict *qdict)
> +{
> +    int64_t handle = qdict_get_int(qdict, "handle");
> +    InstrUnloadResult *res = qmp_instr_unload(handle, NULL);
> +    switch (res->code) {
> +    case INSTR_UNLOAD_CODE_OK:
> +        monitor_printf(mon, "OK\n");
> +        break;
> +    case INSTR_UNLOAD_CODE_INVALID:
> +        monitor_printf(mon, "Invalid handle\n");
> +        break;
> +    case INSTR_UNLOAD_CODE_DLERROR:
> +        monitor_printf(mon, "Error unloading library: %s\n", res->msg);
> +        break;
> +    case INSTR_UNLOAD_CODE_UNAVAILABLE:
> +        monitor_printf(mon, "Service not available\n");
> +        break;
> +    default:
> +        fprintf(stderr, "Unknown instrumentation unload code: %d", 
> res->code);
> +        exit(1);
> +        break;
> +    }
> +    qapi_free_InstrUnloadResult(res);
> +}
> +
>  /* Please update hmp-commands.hx when adding or changing commands */
>  static mon_cmd_t info_cmds[] = {
>  #include "hmp-commands-info.h"

Likewise.