tools lib traceevent: Introduce pevent_errno

Define and use error numbers for pevent_parse_event() and get rid of
die() and do_warning() calls. If the function returns non-zero value,
the caller can check the return code and do appropriate things.

I chose the error numbers to be negative not to clash with standard
errno, and as usual, 0 for success.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1345618831-9148-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index 33fcd94..a46cae7 100644 (file)
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -4686,9 +4686,8 @@ static int find_event_handle(struct pevent *pevent, struct event_format *event)
  *
  * /sys/kernel/debug/tracing/events/.../.../format
  */
-int pevent_parse_event(struct pevent *pevent,
-                      const char *buf, unsigned long size,
-                      const char *sys)
+enum pevent_errno pevent_parse_event(struct pevent *pevent, const char *buf,
+                                    unsigned long size, const char *sys)
 {
        struct event_format *event;
        int ret;
@@ -4697,17 +4696,16 @@ int pevent_parse_event(struct pevent *pevent,
 
        event = alloc_event();
        if (!event)
-               return -ENOMEM;
+               return PEVENT_ERRNO__MEM_ALLOC_FAILED;
 
        event->name = event_read_name();
        if (!event->name) {
                /* Bad event? */
-               free(event);
-               return -1;
+               ret = PEVENT_ERRNO__MEM_ALLOC_FAILED;
+               goto event_alloc_failed;
        }
 
        if (strcmp(sys, "ftrace") == 0) {
-
                event->flags |= EVENT_FL_ISFTRACE;
 
                if (strcmp(event->name, "bprint") == 0)
@@ -4715,20 +4713,28 @@ int pevent_parse_event(struct pevent *pevent,
        }
                
        event->id = event_read_id();
-       if (event->id < 0)
-               die("failed to read event id");
+       if (event->id < 0) {
+               ret = PEVENT_ERRNO__READ_ID_FAILED;
+               /*
+                * This isn't an allocation error actually.
+                * But as the ID is critical, just bail out.
+                */
+               goto event_alloc_failed;
+       }
 
        event->system = strdup(sys);
-       if (!event->system)
-               die("failed to allocate system");
+       if (!event->system) {
+               ret = PEVENT_ERRNO__MEM_ALLOC_FAILED;
+               goto event_alloc_failed;
+       }
 
        /* Add pevent to event so that it can be referenced */
        event->pevent = pevent;
 
        ret = event_read_format(event);
        if (ret < 0) {
-               do_warning("failed to read event format for %s", event->name);
-               goto event_failed;
+               ret = PEVENT_ERRNO__READ_FORMAT_FAILED;
+               goto event_parse_failed;
        }
 
        /*
@@ -4740,10 +4746,9 @@ int pevent_parse_event(struct pevent *pevent,
 
        ret = event_read_print(event);
        if (ret < 0) {
-               do_warning("failed to read event print fmt for %s",
-                          event->name);
                show_warning = 1;
-               goto event_failed;
+               ret = PEVENT_ERRNO__READ_PRINT_FAILED;
+               goto event_parse_failed;
        }
        show_warning = 1;
 
@@ -4760,10 +4765,9 @@ int pevent_parse_event(struct pevent *pevent,
                        arg->type = PRINT_FIELD;
                        arg->field.name = strdup(field->name);
                        if (!arg->field.name) {
-                               do_warning("failed to allocate field name");
                                event->flags |= EVENT_FL_FAILED;
                                free_arg(arg);
-                               return -1;
+                               return PEVENT_ERRNO__OLD_FTRACE_ARG_FAILED;
                        }
                        arg->field.field = field;
                        *list = arg;
@@ -4778,11 +4782,17 @@ int pevent_parse_event(struct pevent *pevent,
 
        return 0;
 
- event_failed:
+ event_parse_failed:
        event->flags |= EVENT_FL_FAILED;
        /* still add it even if it failed */
        add_event(pevent, event);
-       return -1;
+       return ret;
+
+ event_alloc_failed:
+       free(event->system);
+       free(event->name);
+       free(event);
+       return ret;
 }
 
 int get_field_val(struct trace_seq *s, struct format_field *field,

diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index 5772ad8..3c48229 100644 (file)
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -345,6 +345,28 @@ enum pevent_flag {
        PEVENT_NSEC_OUTPUT              = 1,    /* output in NSECS */
 };
 
+enum pevent_errno {
+       PEVENT_ERRNO__SUCCESS                   = 0,
+
+       /*
+        * Choose an arbitrary negative big number not to clash with standard
+        * errno since SUS requires the errno has distinct positive values.
+        * See 'Issue 6' in the link below.
+        *
+        * http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/errno.h.html
+        */
+       __PEVENT_ERRNO__START                   = -100000,
+
+       PEVENT_ERRNO__MEM_ALLOC_FAILED          = __PEVENT_ERRNO__START,
+       PEVENT_ERRNO__PARSE_EVENT_FAILED,
+       PEVENT_ERRNO__READ_ID_FAILED,
+       PEVENT_ERRNO__READ_FORMAT_FAILED,
+       PEVENT_ERRNO__READ_PRINT_FAILED,
+       PEVENT_ERRNO__OLD_FTRACE_ARG_FAILED,
+
+       __PEVENT_ERRNO__END,
+};
+
 struct cmdline;
 struct cmdline_list;
 struct func_map;
@@ -509,8 +531,8 @@ void pevent_print_event(struct pevent *pevent, struct trace_seq *s,
 int pevent_parse_header_page(struct pevent *pevent, char *buf, unsigned long size,
                             int long_size);
 
-int pevent_parse_event(struct pevent *pevent, const char *buf,
-                      unsigned long size, const char *sys);
+enum pevent_errno pevent_parse_event(struct pevent *pevent, const char *buf,
+                                    unsigned long size, const char *sys);
 
 void *pevent_get_field_raw(struct trace_seq *s, struct event_format *event,
                           const char *name, struct pevent_record *record,