lsfd: add --dump-counters option

User may wonder how the built-in counters are defined.
Describing their definitions in lsfd(1) is one of choice.
However, the definitions may drastically change in the future
development.

--dump-counters option is for making lsfd self descriptive.
Users who understand the filter expressions can understand
directly the meaning of the counters.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

diff --git a/misc-utils/lsfd.1.adoc b/misc-utils/lsfd.1.adoc
index a5f39b4249fbebf795d285f00107ffc610a578b1..1a6149a9853a5f5daa9d96b848970531d27235da 100644 (file)
--- a/misc-utils/lsfd.1.adoc
+++ b/misc-utils/lsfd.1.adoc
@@ -97,6 +97,9 @@ CAUTION: Using *--summary* and *--json* may make the output broken. Only combini
 Dump the internal data structure for the filter and exit. This is useful
 only for lsfd developers.
 
+*--dump-counters*::
+Dump the definition of counters used in *--summary* output.
+
 *-h*, *--help*::
 Display help text and exit.
 

diff --git a/misc-utils/lsfd.c b/misc-utils/lsfd.c
index 5d9274059e04df717866df74e721b6461c98ff0f..bd18749ccd7629b82ab753bca6a3b162e0622658 100644 (file)
--- a/misc-utils/lsfd.c
+++ b/misc-utils/lsfd.c
@@ -1145,6 +1145,7 @@ static void __attribute__((__noreturn__)) usage(void)
        fputs(_("     --debug-filter    dump the innternal data structure of filter and exit\n"), out);
        fputs(_(" -C, --counter <name>:<expr>\n"
                "                       make a counter used in --summary output\n"), out);
+       fputs(_("     --dump-counters   dump counter definitions\n"), out);
        fputs(_("     --summary[=when]  print summary information (never,always or only)\n"), out);
 
        fputs(USAGE_SEPARATOR, out);
@@ -1305,6 +1306,29 @@ static struct lsfd_counter **new_default_counters(struct lsfd_control *ctl)
        return counters;
 }
 
+static void dump_default_counter_specs(void)
+{
+       size_t len = ARRAY_SIZE(default_counter_specs);
+       size_t i;
+
+       puts("default counter specs:");
+       for (i = 0; i < len; i++) {
+               struct counter_spec *spec = default_counter_specs + i;
+               printf("\t%s:%s\n", spec->name, spec->expr);
+       }
+}
+
+static void dump_counter_specs(struct list_head *specs)
+{
+       struct list_head *s;
+
+       puts("custom counter specs:");
+       list_for_each(s, specs) {
+               struct counter_spec *spec = list_entry(s, struct counter_spec, specs);
+               printf("\t%s:%s\n", spec->name, spec->expr);
+       }
+}
+
 static struct libscols_table *new_summary_table(struct lsfd_control *ctl)
 {
        struct libscols_table *tb = scols_new_table();
@@ -1372,6 +1396,7 @@ int main(int argc, char *argv[])
        struct lsfd_control ctl = {};
        char  *filter_expr = NULL;
        bool debug_filter = false;
+       bool dump_counters = false;
        pid_t *pids = NULL;
        int n_pids = 0;
        struct list_head counter_specs;
@@ -1381,6 +1406,7 @@ int main(int argc, char *argv[])
        enum {
                OPT_DEBUG_FILTER = CHAR_MAX + 1,
                OPT_SUMMARY,
+               OPT_DUMP_COUNTERS,
        };
        static const struct option longopts[] = {
                { "noheadings", no_argument, NULL, 'n' },
@@ -1396,6 +1422,7 @@ int main(int argc, char *argv[])
                { "debug-filter",no_argument, NULL, OPT_DEBUG_FILTER },
                { "summary",    optional_argument, NULL,  OPT_SUMMARY },
                { "counter",    required_argument, NULL, 'C' },
+               { "dump-counters",no_argument, NULL, OPT_DUMP_COUNTERS },
                { NULL, 0, NULL, 0 },
        };
 
@@ -1451,6 +1478,9 @@ int main(int argc, char *argv[])
                        } else
                                ctl.summary |= SUMMARY_EMIT;
                        break;
+               case OPT_DUMP_COUNTERS:
+                       dump_counters = true;
+                       break;
                case 'V':
                        print_version(EXIT_SUCCESS);
                case 'h':
@@ -1510,6 +1540,14 @@ int main(int argc, char *argv[])
                free(filter_expr);
        }
 
+       if (dump_counters) {
+               if (list_empty(&counter_specs))
+                       dump_default_counter_specs();
+               else
+                       dump_counter_specs(&counter_specs);
+               return 0;
+       }
+
        /* make counters */
        if (ctl.summary & SUMMARY_EMIT) {
                if (list_empty(&counter_specs))