[lttng-dev] [RFC PATCH lttng-tools] Fix: convey enum value signedness into metadata

[Mathieu Desnoyers]

Currently, passing an enum range of:

    ctf_enum_range("blah", 0, UINT_MAX)

in LTTng-UST will print a range of 0 ... -1 in the generated CTF
metadata, which does not reflect signedness of the values.

Also, struct ustctl_enum_entry is missing a LTTNG_PACKED attribute,
which is against our protocol rules.

This change needs to be pushed in locked-step into lttng-tools and
lttng-ust, since it breaks the protocol between the two when UST
uses the new enumeration type (introduced in 2.8.0-rc1).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
---
 src/bin/lttng-sessiond/lttng-ust-ctl.h | 11 +++++++++--
 src/bin/lttng-sessiond/ust-metadata.c  | 28 ++++++++++++++++++++--------
 src/bin/lttng-sessiond/ust-registry.c  | 13 +++++++++++--
 3 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/src/bin/lttng-sessiond/lttng-ust-ctl.h b/src/bin/lttng-sessiond/lttng-ust-ctl.h
index 1ea7b93..b8cf775 100644
--- a/src/bin/lttng-sessiond/lttng-ust-ctl.h
+++ b/src/bin/lttng-sessiond/lttng-ust-ctl.h
@@ -286,12 +286,19 @@ struct ustctl_float_type {
 	char padding[USTCTL_UST_FLOAT_TYPE_PADDING];
 } LTTNG_PACKED;
 
+#define USTCTL_UST_ENUM_VALUE_PADDING	15
+struct ustctl_enum_value {
+	uint64_t value;
+	uint8_t signedness;
+	char padding[USTCTL_UST_ENUM_VALUE_PADDING];
+} LTTNG_PACKED;
+
 #define USTCTL_UST_ENUM_ENTRY_PADDING	32
 struct ustctl_enum_entry {
-	uint64_t start, end;		/* start and end are inclusive */
+	struct ustctl_enum_value start, end; /* start and end are inclusive */
 	char string[LTTNG_UST_SYM_NAME_LEN];
 	char padding[USTCTL_UST_ENUM_ENTRY_PADDING];
-};
+} LTTNG_PACKED;
 
 #define USTCTL_UST_BASIC_TYPE_PADDING	296
 union _ustctl_basic_type {
diff --git a/src/bin/lttng-sessiond/ust-metadata.c b/src/bin/lttng-sessiond/ust-metadata.c
index e49f237..170a397 100644
--- a/src/bin/lttng-sessiond/ust-metadata.c
+++ b/src/bin/lttng-sessiond/ust-metadata.c
@@ -304,18 +304,30 @@ int ust_metadata_enum_statedump(struct ust_registry_session *session,
 		if (ret) {
 			goto end;
 		}
-		if (entry->start == entry->end) {
+
+		if (entry->start.signedness)
 			ret = lttng_metadata_printf(session,
-					"%d,\n",
-					entry->start);
-		} else {
+				"%lld", (long long) entry->start.value);
+		else
 			ret = lttng_metadata_printf(session,
-					"%d ... %d,\n",
-					entry->start, entry->end);
-		}
-		if (ret) {
+				"%llu", entry->start.value);
+		if (ret)
 			goto end;
+		if (entry->start.signedness == entry->end.signedness &&
+				entry->start.value == entry->end.value) {
+			ret = lttng_metadata_printf(session,
+				",\n");
+		} else {
+			if (entry->end.signedness) {
+				ret = lttng_metadata_printf(session,
+					" ... %lld,\n", (long long) entry->end.value);
+			} else {
+				ret = lttng_metadata_printf(session,
+					" ... %llu,\n", entry->end.value);
+			}
 		}
+		if (ret)
+			goto end;
 	}
 	sanitize_ctf_identifier(identifier, field_name);
 	ret = print_tabs(session, nesting);
diff --git a/src/bin/lttng-sessiond/ust-registry.c b/src/bin/lttng-sessiond/ust-registry.c
index dea443d..6913487 100644
--- a/src/bin/lttng-sessiond/ust-registry.c
+++ b/src/bin/lttng-sessiond/ust-registry.c
@@ -89,14 +89,23 @@ static int compare_enums(const struct ust_registry_enum *reg_enum_a,
 
 		entries_a = &reg_enum_a->entries[i];
 		entries_b = &reg_enum_b->entries[i];
-		if (entries_a->start != entries_b->start) {
+		if (entries_a->start.value != entries_b->start.value) {
 			ret = -1;
 			goto end;
 		}
-		if (entries_a->end != entries_b->end) {
+		if (entries_a->end.value != entries_b->end.value) {
 			ret = -1;
 			goto end;
 		}
+		if (entries_a->start.signedness != entries_b->start.signedness) {
+			ret = -1;
+			goto end;
+		}
+		if (entries_a->end.signedness != entries_b->end.signedness) {
+			ret = -1;
+			goto end;
+		}
+
 		if (strcmp(entries_a->string, entries_b->string)) {
 			ret = -1;
 			goto end;
-- 
2.1.4