[PATCH] perf-script : improves option passing mechansim

[Adrien BAK <adrien.bak@metascale.org>]

This pull request fixes the following issues :
* when passing custom arguments to a script, if those arguments are
  not declared within perf, they prevent the execution of perf.
e.g.

perf script -i path/to/perf.data -s my_script -arg1 arg_value

perf will issue an error message and no processing will occur


* when passing custom arguments to a script, if those arguments are
  declared by perf, they are consumed and not passed to the script.
e.g.
perf script -i path/to/perf.data -s my_script -h

perf will display its own help message, instead of the expected help
message from my_script.

These issues are addressed as follows :
* The parse option flag is changed from PARSE_OPT_STOP_AT_NON_OPTION to
PARSE_OPT_KEEP_UNKNOWN
* A new option type is introduce OPT_CALLBACK_FINAL_OPTION, which 
effectively
  prevents the parsing of all options located after the script.

Signed-off-by: Adrien Bak <adrien.bak@metascale.org>

---

  tools/perf/builtin-script.c     | 8 ++++----
  tools/perf/util/parse-options.c | 4 ++++
  tools/perf/util/parse-options.h | 5 +++++
  3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 9e9c91f..3cd6a46 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1523,9 +1523,9 @@ int cmd_script(int argc, const char **argv, const 
char *prefix __maybe_unused)
              "show latency attributes (irqs/preemption disabled, etc)"),
      OPT_CALLBACK_NOOPT('l', "list", NULL, NULL, "list available scripts",
                 list_available_scripts),
-    OPT_CALLBACK('s', "script", NULL, "name",
-             "script file name (lang:script name, script name, or *)",
-             parse_scriptname),
+    OPT_CALLBACK_FINAL_OPTION('s', "script", NULL, "name",
+                  "script file name (lang:script name, script name, or *)",
+                  parse_scriptname),
      OPT_STRING('g', "gen-script", &generate_script_lang, "lang",
             "generate perf-script.xx script in specified language"),
      OPT_STRING('i', "input", &input_name, "file", "input file name"),
@@ -1578,7 +1578,7 @@ int cmd_script(int argc, const char **argv, const 
char *prefix __maybe_unused)
      setup_scripting();

      argc = parse_options(argc, argv, options, script_usage,
-                 PARSE_OPT_STOP_AT_NON_OPTION);
+                 PARSE_OPT_KEEP_UNKNOWN);

      file.path = input_name;

diff --git a/tools/perf/util/parse-options.c 
b/tools/perf/util/parse-options.c
index d22e3f8..77f566d 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -112,6 +112,8 @@ static int get_value(struct parse_opt_ctx_t *p,
              return (*opt->callback)(opt, NULL, 0) ? (-1) : 0;
          if (get_arg(p, opt, flags, &arg))
              return -1;
+        if (opt->flags & PARSE_OPT_FINAL_OPTION)
+            return (*opt->callback)(opt, arg, 0)?(-1) : (-3);
          return (*opt->callback)(opt, arg, 0) ? (-1) : 0;

      case OPTION_INTEGER:
@@ -366,6 +368,8 @@ int parse_options_step(struct parse_opt_ctx_t *ctx,
                  return parse_options_usage(usagestr, options, arg + 1, 1);
              case -2:
                  goto unknown;
+            case -3:
+                return PARSE_OPT_DONE;
              default:
                  break;
              }
diff --git a/tools/perf/util/parse-options.h 
b/tools/perf/util/parse-options.h
index cbf0149..b1fa6b6 100644
--- a/tools/perf/util/parse-options.h
+++ b/tools/perf/util/parse-options.h
@@ -38,6 +38,7 @@ enum parse_opt_option_flags {
      PARSE_OPT_NONEG   = 4,
      PARSE_OPT_HIDDEN  = 8,
      PARSE_OPT_LASTARG_DEFAULT = 16,
+    PARSE_OPT_FINAL_OPTION = 32,
  };

  struct option;
@@ -123,6 +124,10 @@ struct option {
      { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), 
.value = (v), .argh = "time", .help = (h), .callback = 
parse_opt_approxidate_cb }
  #define OPT_CALLBACK(s, l, v, a, h, f) \
      { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), 
.value = (v), (a), .help = (h), .callback = (f) }
+#define OPT_CALLBACK_FINAL_OPTION(s, l, v, a, h, f) \
+    { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l),\
+    .value = (v), (a), .help = (h), .callback = (f),\
+    .flags = PARSE_OPT_FINAL_OPTION}
  #define OPT_CALLBACK_NOOPT(s, l, v, a, h, f) \
      { .type = OPTION_CALLBACK, .short_name = (s), .long_name = (l), 
.value = (v), (a), .help = (h), .callback = (f), .flags = PARSE_OPT_NOARG }
  #define OPT_CALLBACK_DEFAULT(s, l, v, a, h, f, d) \