Add support for new common fields

Current parser covers common fields with: u64 __do_not_use__ so the new common fields are not accounted for. Keeping the 'u64 __do_not_use__' field for backward compatibility (who knows who's actualy using it) and adding new fields, like: char __do_not_use__X for each byte of extra common fields, where X is the offset of the field. With this fix the bcc-tools correctly parses tracepoints on RT kernel and it's usable again. Signed-off-by: Jiri Olsa <[email protected]>
Ha-Dj · Mar 15, 2020 · 0a9d6db · 0a9d6db
1 parent b8423e6
commit 0a9d6db
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Showing 2 changed files with 40 additions and 1 deletion.
diff --git a/src/cc/common.cc b/src/cc/common.cc
@@ -165,7 +165,7 @@ std::string parse_tracepoint(std::istream &input, std::string const& category,
  std::string const& event) {
  std::string tp_struct = "struct tracepoint__" + category + "__" + event + " {\n";
  tp_struct += "\tu64 __do_not_use__;\n";
- int last_offset = 0;
+ int last_offset = 0, common_offset = 8;
  for (std::string line; getline(input, line); ) {
  std::string field_type, field_name;
  field_kind_t kind;
@@ -175,7 +175,12 @@ std::string parse_tracepoint(std::istream &input, std::string const& category,
 
  switch (kind) {
  case field_kind_t::invalid:
+ continue;
  case field_kind_t::common:
+ for (;common_offset < last_offset; common_offset++)
+ {
+ tp_struct += "\tchar __do_not_use__" + std::to_string(common_offset) + ";\n";
+ }
  continue;
  case field_kind_t::data_loc:
  tp_struct += "\tint data_loc_" + field_name + ";\n";

diff --git a/tests/cc/test_parse_tracepoint.cc b/tests/cc/test_parse_tracepoint.cc
@@ -74,4 +74,38 @@ TEST_CASE("test tracepoint parser", "[TracepointParser]") {
  std::string result = ebpf::parse_tracepoint(input, "signal", "signal_deliver");
  REQUIRE(expected == result);
  }
+
+ format =
+ " field:unsigned short common_type; offset:0; size:2; signed:0;\n"
+ " field:unsigned char common_flags; offset:2; size:1; signed:0;\n"
+ " field:unsigned char common_preempt_count; offset:3; size:1; signed:0;\n"
+ " field:int common_pid; offset:4; size:4; signed:1;\n"
+ " field:unsigned char common_migrate_disable; offset:8; size:1; signed:0;\n"
+ " field:unsigned char common_preempt_lazy_count; offset:9; size:1; signed:0;\n"
+
+ " field:char comm[16]; offset:12; size:16; signed:1;\n"
+ " field:pid_t pid; offset:28; size:4; signed:1;\n"
+ " field:int prio; offset:32; size:4; signed:1;\n"
+ " field:int success; offset:36; size:4; signed:1;\n"
+ " field:int target_cpu; offset:40; size:4; signed:1;\n";
+
+ expected =
+ "struct tracepoint__sched__sched_wakeup {\n"
+ "\tu64 __do_not_use__;\n"
+ "\tchar __do_not_use__8;\n"
+ "\tchar __do_not_use__9;\n"
+ "\tchar __pad_10;\n"
+ "\tchar __pad_11;\n"
+ "\tchar comm[16];\n"
+ "\tpid_t pid;\n"
+ "\tint prio;\n"
+ "\tint success;\n"
+ "\tint target_cpu;\n"
+ "};\n";
+
+ {
+ std::istringstream input(format);
+ std::string result = ebpf::parse_tracepoint(input, "sched", "sched_wakeup");
+ REQUIRE(expected == result);
+ }
 }