libtraceevent: Add __rel_loc relative location attribute support

Add '__rel_loc' new dynamic data location attribute which encodes
the data location from the next to the field itself. This is similar
to the '__data_loc' but the location offset is not from the event
entry but from the next of the field.

This patch adds '__rel_loc' decoding support in the libtraceevent.

Link: https://lkml.kernel.org/r/163757343994.510314.13241077597729303802.stgit@devnote2
Cc: Beau Belgrave <beaub@linux.microsoft.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c
index fe58843d047ca3d1f8a9e62be8d8f3de3f1cbb76..8e24c4c78c7f0b89fb63e9b8e45b3e273f08699c 100644 (file)
--- a/tools/lib/traceevent/event-parse.c
+++ b/tools/lib/traceevent/event-parse.c
@@ -1367,6 +1367,14 @@ static int field_is_dynamic(struct tep_format_field *field)
        return 0;
 }
 
+static int field_is_relative_dynamic(struct tep_format_field *field)
+{
+       if (strncmp(field->type, "__rel_loc", 9) == 0)
+               return 1;
+
+       return 0;
+}
+
 static int field_is_long(struct tep_format_field *field)
 {
        /* includes long long */
@@ -1622,6 +1630,8 @@ static int event_read_fields(struct tep_event *event, struct tep_format_field **
                        field->flags |= TEP_FIELD_IS_STRING;
                if (field_is_dynamic(field))
                        field->flags |= TEP_FIELD_IS_DYNAMIC;
+               if (field_is_relative_dynamic(field))
+                       field->flags |= TEP_FIELD_IS_DYNAMIC | TEP_FIELD_IS_RELATIVE;
                if (field_is_long(field))
                        field->flags |= TEP_FIELD_IS_LONG;
 
@@ -2928,7 +2938,7 @@ process_str(struct tep_event *event __maybe_unused, struct tep_print_arg *arg,
 
        arg->type = TEP_PRINT_STRING;
        arg->string.string = token;
-       arg->string.offset = -1;
+       arg->string.field = NULL;
 
        if (read_expected(TEP_EVENT_DELIM, ")") < 0)
                goto out_err;
@@ -2957,7 +2967,7 @@ process_bitmask(struct tep_event *event __maybe_unused, struct tep_print_arg *ar
 
        arg->type = TEP_PRINT_BITMASK;
        arg->bitmask.bitmask = token;
-       arg->bitmask.offset = -1;
+       arg->bitmask.field = NULL;
 
        if (read_expected(TEP_EVENT_DELIM, ")") < 0)
                goto out_err;
@@ -3123,19 +3133,23 @@ process_function(struct tep_event *event, struct tep_print_arg *arg,
                free_token(token);
                return process_int_array(event, arg, tok);
        }
-       if (strcmp(token, "__get_str") == 0) {
+       if (strcmp(token, "__get_str") == 0 ||
+           strcmp(token, "__get_rel_str") == 0) {
                free_token(token);
                return process_str(event, arg, tok);
        }
-       if (strcmp(token, "__get_bitmask") == 0) {
+       if (strcmp(token, "__get_bitmask") == 0 ||
+           strcmp(token, "__get_rel_bitmask") == 0) {
                free_token(token);
                return process_bitmask(event, arg, tok);
        }
-       if (strcmp(token, "__get_dynamic_array") == 0) {
+       if (strcmp(token, "__get_dynamic_array") == 0 ||
+           strcmp(token, "__get_rel_dynamic_array") == 0) {
                free_token(token);
                return process_dynamic_array(event, arg, tok);
        }
-       if (strcmp(token, "__get_dynamic_array_len") == 0) {
+       if (strcmp(token, "__get_dynamic_array_len") == 0 ||
+           strcmp(token, "__get_rel_dynamic_array_len") == 0) {
                free_token(token);
                return process_dynamic_array_len(event, arg, tok);
        }
@@ -4163,14 +4177,16 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
        case TEP_PRINT_STRING: {
                int str_offset;
 
-               if (arg->string.offset == -1) {
-                       struct tep_format_field *f;
+               if (!arg->string.field)
+                       arg->string.field = tep_find_any_field(event, arg->string.string);
+               if (!arg->string.field)
+                       break;
 
-                       f = tep_find_any_field(event, arg->string.string);
-                       arg->string.offset = f->offset;
-               }
-               str_offset = data2host4(tep, *(unsigned int *)(data + arg->string.offset));
+               str_offset = data2host4(tep,
+                               *(unsigned int *)(data + arg->string.field->offset));
                str_offset &= 0xffff;
+               if (arg->string.field->flags & TEP_FIELD_IS_RELATIVE)
+                       str_offset += arg->string.field->offset + arg->string.field->size;
                print_str_to_seq(s, format, len_arg, ((char *)data) + str_offset);
                break;
        }
@@ -4181,15 +4197,16 @@ static void print_str_arg(struct trace_seq *s, void *data, int size,
                int bitmask_offset;
                int bitmask_size;
 
-               if (arg->bitmask.offset == -1) {
-                       struct tep_format_field *f;
-
-                       f = tep_find_any_field(event, arg->bitmask.bitmask);
-                       arg->bitmask.offset = f->offset;
-               }
-               bitmask_offset = data2host4(tep, *(unsigned int *)(data + arg->bitmask.offset));
+               if (!arg->bitmask.field)
+                       arg->bitmask.field = tep_find_any_field(event, arg->bitmask.bitmask);
+               if (!arg->bitmask.field)
+                       break;
+               bitmask_offset = data2host4(tep,
+                               *(unsigned int *)(data + arg->bitmask.field->offset));
                bitmask_size = bitmask_offset >> 16;
                bitmask_offset &= 0xffff;
+               if (arg->bitmask.field->flags & TEP_FIELD_IS_RELATIVE)
+                       bitmask_offset += arg->bitmask.field->offset + arg->bitmask.field->size;
                print_bitmask_to_seq(tep, s, format, len_arg,
                                     data + bitmask_offset, bitmask_size);
                break;
@@ -5109,6 +5126,8 @@ void tep_print_field(struct trace_seq *s, void *data,
                        offset = val;
                        len = offset >> 16;
                        offset &= 0xffff;
+                       if (field->flags & TEP_FIELD_IS_RELATIVE)
+                               offset += field->offset + field->size;
                }
                if (field->flags & TEP_FIELD_IS_STRING &&
                    is_printable_array(data + offset, len)) {
@@ -6987,6 +7006,8 @@ void *tep_get_field_raw(struct trace_seq *s, struct tep_event *event,
                                         data + offset, field->size);
                *len = offset >> 16;
                offset &= 0xffff;
+               if (field->flags & TEP_FIELD_IS_RELATIVE)
+                       offset += field->offset + field->size;
        } else
                *len = field->size;
 

diff --git a/tools/lib/traceevent/event-parse.h b/tools/lib/traceevent/event-parse.h
index a67ad9a5b835a27e48372bbc337b6e4453ec8391..41d4f9f6a8436764b7b335f32a9747fe2d32f713 100644 (file)
--- a/tools/lib/traceevent/event-parse.h
+++ b/tools/lib/traceevent/event-parse.h
@@ -125,6 +125,7 @@ enum tep_format_flags {
        TEP_FIELD_IS_LONG       = 32,
        TEP_FIELD_IS_FLAG       = 64,
        TEP_FIELD_IS_SYMBOLIC   = 128,
+       TEP_FIELD_IS_RELATIVE   = 256,
 };
 
 struct tep_format_field {
@@ -153,12 +154,12 @@ struct tep_print_arg_atom {
 
 struct tep_print_arg_string {
        char                    *string;
-       int                     offset;
+       struct tep_format_field *field;
 };
 
 struct tep_print_arg_bitmask {
        char                    *bitmask;
-       int                     offset;
+       struct tep_format_field *field;
 };
 
 struct tep_print_arg_field {

diff --git a/tools/lib/traceevent/parse-filter.c b/tools/lib/traceevent/parse-filter.c
index 368826bb5a572988acd091bbffbd682d2023c2e2..5df177070d53a05a390c973e6ee39b31e911ac0b 100644 (file)
--- a/tools/lib/traceevent/parse-filter.c
+++ b/tools/lib/traceevent/parse-filter.c
@@ -1712,8 +1712,11 @@ static const char *get_field_str(struct tep_filter_arg *arg, struct tep_record *
 
                if (arg->str.field->flags & TEP_FIELD_IS_DYNAMIC) {
                        addr = *(unsigned int *)val;
-                       val = record->data + (addr & 0xffff);
                        size = addr >> 16;
+                       addr &= 0xffff;
+                       if (arg->str.field->flags & TEP_FIELD_IS_RELATIVE)
+                               addr += arg->str.field->offset + arg->str.field->size;
+                       val = record->data + addr;
                }
 
                /*