Kernel: add feature check for ctf2 based on lttng-modules ABI

TODO: change the actual value when actually upstreaming

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I80f1fa9281e3ae4db3b7f8d42f19a6ba38bfa23a

diff --git a/include/lttng/lttng-error.h b/include/lttng/lttng-error.h
index 790a78a0b60e88188486fc230b84c01ba031f347..1438e0dc25178a7ad5270a9ef5106d8a596af12b 100644 (file)
--- a/include/lttng/lttng-error.h
+++ b/include/lttng/lttng-error.h
@@ -183,6 +183,7 @@ enum lttng_error_code {
        LTTNG_ERR_EVENT_NOTIFIER_ERROR_ACCOUNTING_FULL = 168, /* Error event notifier error accounting full. */
        LTTNG_ERR_INVALID_ERROR_QUERY_TARGET = 169, /* Invalid error query target. */
        LTTNG_ERR_BUFFER_FLUSH_FAILED        = 170, /* Buffer flush failed */
+       LTTNG_ERR_TRACE_FORMAT_UNSUPPORTED_KERNEL_TRACER = 171, /* Kernel tracer does not support the specified trace format */
 
        /* MUST be last element of the manually-assigned section of the enum */
        LTTNG_ERR_NR,

diff --git a/src/bin/lttng-sessiond/cmd.cpp b/src/bin/lttng-sessiond/cmd.cpp
index d5f46188895fa7e7af29d18dddb855677938a274..158fb0d75a22a155a6442892c2aadc6318252b91 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.cpp
+++ b/src/bin/lttng-sessiond/cmd.cpp
@@ -1286,6 +1286,23 @@ end:
        return ret;
 }
 
+static enum lttng_error_code kernel_domain_check_trace_format_requirements(
+               const lttng::trace_format_descriptor& descriptor)
+{
+       enum lttng_error_code ret_code;
+       switch (descriptor.type()) {
+       case LTTNG_TRACE_FORMAT_DESCRIPTOR_TYPE_CTF_1:
+               /* Supported by all kernel tracer. */
+               ret_code = LTTNG_OK;
+               break;
+       case LTTNG_TRACE_FORMAT_DESCRIPTOR_TYPE_CTF_2:
+               if (!kernel_supports_ctf2()) {
+                       ret_code = LTTNG_ERR_TRACE_FORMAT_UNSUPPORTED_KERNEL_TRACER;
+               }
+       }
+       return LTTNG_OK;
+}
+
 static enum lttng_error_code cmd_enable_channel_internal(
                struct ltt_session *session,
                const struct lttng_domain *domain,
@@ -1343,6 +1360,13 @@ static enum lttng_error_code cmd_enable_channel_internal(
                                        attr->name, session->name);
                        lttng_channel_set_monitor_timer_interval(attr, 0);
                }
+
+               ret_code = kernel_domain_check_trace_format_requirements(*session->trace_format);
+               if (ret_code != LTTNG_OK) {
+                       WARN("Kernel tracer does not support the configured trace format of session '%s'",
+                                       session->name);
+                       goto error;
+               }
                break;
        }
        case LTTNG_DOMAIN_UST:

diff --git a/src/bin/lttng-sessiond/kernel.cpp b/src/bin/lttng-sessiond/kernel.cpp
index f7d232ffc01aadb346b5fdf6d8c4928ea5163727..2831a039e3bff63a12d343e03987e1e02e1ef97f 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.cpp
+++ b/src/bin/lttng-sessiond/kernel.cpp
@@ -1837,6 +1837,22 @@ int kernel_supports_event_notifiers(void)
        return kernel_tracer_abi_greater_or_equal(2, 6);
 }
 
+/*
+ * Check for the support of ctf2 via abi version number.
+ *
+ * Return 1 on success, 0 when feature is not supported, negative value in case
+ * of errors.
+ */
+int kernel_supports_ctf2(void)
+{
+       /*
+        * JORAJ TODO: change this for the actual value when merged upstream
+        *             default to 2.7 ABI for now (modules 2.14)
+        * CTF2 support was introduced in LTTng 2.1XX, lttng-modules ABI 2.XX.
+        */
+       return kernel_tracer_abi_greater_or_equal(2, 7);
+}
+
 /*
  * Rotate a kernel session.
  *

diff --git a/src/bin/lttng-sessiond/kernel.hpp b/src/bin/lttng-sessiond/kernel.hpp
index bb01651213dfd211dd75ba459e70f59f9c91916c..a3fb9e5988004b960b29bab6705ed1a9fca6ef4a 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.hpp
+++ b/src/bin/lttng-sessiond/kernel.hpp
@@ -72,6 +72,7 @@ enum lttng_error_code kernel_rotate_session(struct ltt_session *session);
 enum lttng_error_code kernel_clear_session(struct ltt_session *session);
 
 int init_kernel_workarounds(void);
+int kernel_supports_ctf2(void);
 int kernel_supports_ring_buffer_snapshot_sample_positions(void);
 int kernel_supports_ring_buffer_packet_sequence_number(void);
 int kernel_supports_event_notifiers(void);

diff --git a/src/common/error.cpp b/src/common/error.cpp
index 150d2e53fbfe75ef02517a766356eea7db809f7d..40c1faf0b9a6379866d30eceaf2e14ab534706ab 100644 (file)
--- a/src/common/error.cpp
+++ b/src/common/error.cpp
@@ -404,6 +404,8 @@ const char *lttng_error_code_str(lttng_error_code code)
                return "Invalid error query target.";
        case LTTNG_ERR_BUFFER_FLUSH_FAILED:
                return "Failed to flush stream buffer";
+       case LTTNG_ERR_TRACE_FORMAT_UNSUPPORTED_KERNEL_TRACER:
+               return "Kernel tracer does not support the specified trace format";
        case LTTNG_ERR_NR:
                abort();
        }