Implement PID tracking for kernel tracing

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 2aeef263d6bd38c7238db96b0c99de4d230bdee2..4bb418949d3ea330b60397ed2352f5541c7fcbdc 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -16,6 +16,7 @@
  */
 
 #define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -26,6 +27,7 @@
 
 #include <common/common.h>
 #include <common/kernel-ctl/kernel-ctl.h>
+#include <common/kernel-ctl/kernel-ioctl.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 
 #include "consumer.h"
@@ -172,6 +174,7 @@ error:
 /*
  * Create a kernel event, enable it to the kernel tracer and add it to the
  * channel event list of the kernel session.
+ * We own filter_expression and filter.
  */
 int kernel_create_event(struct lttng_event *ev,
                struct ltt_kernel_channel *channel)
@@ -364,6 +367,20 @@ int kernel_disable_syscall(const char *syscall_name,
        return kernctl_disable_syscall(channel->fd, syscall_name);
 }
 
+int kernel_track_pid(struct ltt_kernel_session *session, int pid)
+{
+       DBG("Kernel track PID %d for session id %" PRIu64 ".",
+                       pid, session->id);
+       return kernctl_track_pid(session->fd, pid);
+}
+
+int kernel_untrack_pid(struct ltt_kernel_session *session, int pid)
+{
+       DBG("Kernel untrack PID %d for session id %" PRIu64 ".",
+                       pid, session->id);
+       return kernctl_untrack_pid(session->fd, pid);
+}
+
 /*
  * Create kernel metadata, open from the kernel tracer and add it to the
  * kernel session.
@@ -698,6 +715,7 @@ int kernel_validate_version(int tracer_fd)
 {
        int ret;
        struct lttng_kernel_tracer_version version;
+       struct lttng_kernel_tracer_abi_version abi_version;
 
        ret = kernctl_tracer_version(tracer_fd, &version);
        if (ret < 0) {
@@ -706,17 +724,28 @@ int kernel_validate_version(int tracer_fd)
        }
 
        /* Validate version */
-       if (version.major != KERN_MODULES_PRE_MAJOR
-               && version.major != KERN_MODULES_MAJOR) {
+       if (version.major != VERSION_MAJOR) {
+               ERR("Kernel tracer major version (%d) is not compatible with lttng-tools major version (%d)",
+                       version.major, VERSION_MAJOR);
                goto error_version;
        }
-
-       DBG2("Kernel tracer version validated (major version %d)", version.major);
+       ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
+       if (ret < 0) {
+               ERR("Failed at getting lttng-modules ABI version");
+               goto error;
+       }
+       if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
+               ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
+                       abi_version.major, abi_version.minor,
+                       LTTNG_MODULES_ABI_MAJOR_VERSION);
+               goto error;
+       }
+       DBG2("Kernel tracer version validated (%d.%d, ABI %d.%d)",
+                       version.major, version.minor,
+                       abi_version.major, abi_version.minor);
        return 0;
 
 error_version:
-       ERR("Kernel major version %d is not compatible (supporting <= %d)",
-                       version.major, KERN_MODULES_MAJOR)
        ret = -1;
 
 error:
@@ -779,6 +808,7 @@ void kernel_destroy_session(struct ltt_kernel_session *ksess)
                struct lttng_ht_iter iter;
 
                /* For each consumer socket. */
+               rcu_read_lock();
                cds_lfht_for_each_entry(ksess->consumer->socks->ht, &iter.iter,
                                socket, node.node) {
                        struct ltt_kernel_channel *chan;
@@ -792,6 +822,7 @@ void kernel_destroy_session(struct ltt_kernel_session *ksess)
                                }
                        }
                }
+               rcu_read_unlock();
        }
 
        /* Close any relayd session */
@@ -836,7 +867,8 @@ void kernel_destroy_channel(struct ltt_kernel_channel *kchan)
  * Return 0 on success or else return a LTTNG_ERR code.
  */
 int kernel_snapshot_record(struct ltt_kernel_session *ksess,
-               struct snapshot_output *output, int wait, uint64_t max_size_per_stream)
+               struct snapshot_output *output, int wait,
+               uint64_t nb_packets_per_stream)
 {
        int err, ret, saved_metadata_fd;
        struct consumer_socket *socket;
@@ -897,7 +929,7 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
                        ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
                                        ksess->uid, ksess->gid,
                                        DEFAULT_KERNEL_TRACE_DIR, wait,
-                                       max_size_per_stream);
+                                       nb_packets_per_stream);
                        pthread_mutex_unlock(socket->lock);
                        if (ret < 0) {
                                ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
@@ -911,7 +943,7 @@ int kernel_snapshot_record(struct ltt_kernel_session *ksess,
                pthread_mutex_lock(socket->lock);
                ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
                                1, ksess->uid, ksess->gid,
-                               DEFAULT_KERNEL_TRACE_DIR, wait, max_size_per_stream);
+                               DEFAULT_KERNEL_TRACE_DIR, wait, 0);
                pthread_mutex_unlock(socket->lock);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_CONSUMER_FAIL;