Fix: userspace probe accessors are not const-correct
[lttng-tools.git] / src / bin / lttng-sessiond / main.c
index f9b41d2707bd26aff4f95a72aa1885d2f2f09280..ee50db21e38b2c29a400b1ccec0065f72f28900c 100644 (file)
@@ -49,6 +49,8 @@
 #include <common/utils.h>
 #include <common/daemonize.h>
 #include <common/config/session-config.h>
+#include <common/dynamic-buffer.h>
+#include <lttng/userspace-probe-internal.h>
 
 #include "lttng-sessiond.h"
 #include "buffer-registry.h"
@@ -366,10 +368,21 @@ LTTNG_HIDDEN
 void sessiond_notify_ready(void)
 {
        /*
-        * The _return variant is used since the implied memory barriers are
-        * required.
+        * This memory barrier is paired with the one performed by
+        * the client thread after it has seen that 'lttng_sessiond_ready' is 0.
+        *
+        * The purpose of these memory barriers is to ensure that all
+        * initialization operations of the various threads that call this
+        * function to signal that they are ready are commited/published
+        * before the client thread can see the 'lttng_sessiond_ready' counter
+        * reach 0.
+        *
+        * Note that this could be a 'write' memory barrier, but a full barrier
+        * is used in case the code using this utility changes. The performance
+        * implications of this choice are minimal since this is a slow path.
         */
-       (void) uatomic_sub_return(&lttng_sessiond_ready, 1);
+       cmm_smp_mb();
+       uatomic_sub(&lttng_sessiond_ready, 1);
 }
 
 static
@@ -580,15 +593,9 @@ static void sessiond_cleanup(void)
         */
        utils_close_pipe(thread_quit_pipe);
 
-       /*
-        * If config.pid_file_path.value is undefined, the default file will be
-        * wiped when removing the rundir.
-        */
-       if (config.pid_file_path.value) {
-               ret = remove(config.pid_file_path.value);
-               if (ret < 0) {
-                       PERROR("remove pidfile %s", config.pid_file_path.value);
-               }
+       ret = remove(config.pid_file_path.value);
+       if (ret < 0) {
+               PERROR("remove pidfile %s", config.pid_file_path.value);
        }
 
        DBG("Removing sessiond and consumerd content of directory %s",
@@ -847,7 +854,7 @@ error:
  *
  * Useful for CPU hotplug feature.
  */
-static int update_kernel_stream(struct consumer_data *consumer_data, int fd)
+static int update_kernel_stream(int fd)
 {
        int ret = 0;
        struct ltt_session *session;
@@ -1081,7 +1088,7 @@ static void *thread_manage_kernel(void *data)
                                         * New CPU detected by the kernel. Adding kernel stream to
                                         * kernel session and updating the kernel consumer
                                         */
-                                       ret = update_kernel_stream(&kconsumer_data, pollfd);
+                                       ret = update_kernel_stream(pollfd);
                                        if (ret < 0) {
                                                continue;
                                        }
@@ -2925,6 +2932,112 @@ static unsigned int lttng_sessions_count(uid_t uid, gid_t gid)
        return i;
 }
 
+static int receive_userspace_probe(struct command_ctx *cmd_ctx, int sock,
+               int *sock_error, struct lttng_event *event)
+{
+       int fd, ret;
+       struct lttng_userspace_probe_location *probe_location;
+       const struct lttng_userspace_probe_location_lookup_method *lookup = NULL;
+       struct lttng_dynamic_buffer probe_location_buffer;
+       struct lttng_buffer_view buffer_view;
+
+       /*
+        * Create a buffer to store the serialized version of the probe
+        * location.
+        */
+       lttng_dynamic_buffer_init(&probe_location_buffer);
+       ret = lttng_dynamic_buffer_set_size(&probe_location_buffer,
+                       cmd_ctx->lsm->u.enable.userspace_probe_location_len);
+       if (ret) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error;
+       }
+
+       /*
+        * Receive the probe location.
+        */
+       ret = lttcomm_recv_unix_sock(sock, probe_location_buffer.data,
+                       probe_location_buffer.size);
+       if (ret <= 0) {
+               DBG("Nothing recv() from client var len data... continuing");
+               *sock_error = 1;
+               lttng_dynamic_buffer_reset(&probe_location_buffer);
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       buffer_view = lttng_buffer_view_from_dynamic_buffer(
+                       &probe_location_buffer, 0, probe_location_buffer.size);
+
+       /*
+        * Extract the probe location from the serialized version.
+        */
+       ret = lttng_userspace_probe_location_create_from_buffer(
+                               &buffer_view, &probe_location);
+       if (ret < 0) {
+               WARN("Failed to create a userspace probe location from the received buffer");
+               lttng_dynamic_buffer_reset( &probe_location_buffer);
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * Receive the file descriptor to the target binary from the client.
+        */
+       DBG("Receiving userspace probe target FD from client ...");
+       ret = lttcomm_recv_fds_unix_sock(sock, &fd, 1);
+       if (ret <= 0) {
+               DBG("Nothing recv() from client userspace probe fd... continuing");
+               *sock_error = 1;
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * Set the file descriptor received from the client through the unix
+        * socket in the probe location.
+        */
+       lookup = lttng_userspace_probe_location_get_lookup_method(probe_location);
+       if (!lookup) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /*
+        * From the kernel tracer's perspective, all userspace probe event types
+        * are all the same: a file and an offset.
+        */
+       switch (lttng_userspace_probe_location_lookup_method_get_type(lookup)) {
+       case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF:
+               ret = lttng_userspace_probe_location_function_set_binary_fd(
+                               probe_location, fd);
+               break;
+       case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT:
+               ret = lttng_userspace_probe_location_tracepoint_set_binary_fd(
+                               probe_location, fd);
+               break;
+       default:
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       if (ret) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       /* Attach the probe location to the event. */
+       ret = lttng_event_set_userspace_probe_location(event, probe_location);
+       if (ret) {
+               ret = LTTNG_ERR_PROBE_LOCATION_INVAL;
+               goto error;
+       }
+
+       lttng_dynamic_buffer_reset(&probe_location_buffer);
+error:
+       return ret;
+}
+
 /*
  * Check if the current kernel tracer supports the session rotation feature.
  * Return 1 if it does, 0 otherwise.
@@ -2989,8 +3102,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_ROTATION_GET_INFO:
        case LTTNG_SESSION_GET_CURRENT_OUTPUT:
        case LTTNG_ROTATION_SET_SCHEDULE:
-       case LTTNG_ROTATION_SCHEDULE_GET_TIMER_PERIOD:
-       case LTTNG_ROTATION_SCHEDULE_GET_SIZE:
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
                need_domain = 0;
                break;
        default:
@@ -3035,8 +3147,7 @@ static int process_client_msg(struct command_ctx *cmd_ctx, int sock,
        case LTTNG_DATA_PENDING:
        case LTTNG_ROTATE_SESSION:
        case LTTNG_ROTATION_GET_INFO:
-       case LTTNG_ROTATION_SCHEDULE_GET_TIMER_PERIOD:
-       case LTTNG_ROTATION_SCHEDULE_GET_SIZE:
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
                break;
        default:
                /* Setup lttng message with no payload */
@@ -3465,6 +3576,7 @@ error_add_context:
        }
        case LTTNG_ENABLE_EVENT:
        {
+               struct lttng_event *ev = NULL;
                struct lttng_event_exclusion *exclusion = NULL;
                struct lttng_filter_bytecode *bytecode = NULL;
                char *filter_expression = NULL;
@@ -3516,7 +3628,7 @@ error_add_context:
                        ret = lttcomm_recv_unix_sock(sock, filter_expression,
                                expression_len);
                        if (ret <= 0) {
-                               DBG("Nothing recv() from client car len data... continuing");
+                               DBG("Nothing recv() from client var len data... continuing");
                                *sock_error = 1;
                                free(filter_expression);
                                free(exclusion);
@@ -3548,7 +3660,7 @@ error_add_context:
                        DBG("Receiving var len filter's bytecode from client ...");
                        ret = lttcomm_recv_unix_sock(sock, bytecode, bytecode_len);
                        if (ret <= 0) {
-                               DBG("Nothing recv() from client car len data... continuing");
+                               DBG("Nothing recv() from client var len data... continuing");
                                *sock_error = 1;
                                free(filter_expression);
                                free(bytecode);
@@ -3566,11 +3678,30 @@ error_add_context:
                        }
                }
 
+               ev = lttng_event_copy(&cmd_ctx->lsm->u.enable.event);
+               if (!ev) {
+                       DBG("Failed to copy event: %s",
+                                       cmd_ctx->lsm->u.enable.event.name);
+                       ret = LTTNG_ERR_NOMEM;
+                       goto error;
+               }
+
+
+               if (cmd_ctx->lsm->u.enable.userspace_probe_location_len > 0) {
+                       /* Expect a userspace probe description. */
+                       ret = receive_userspace_probe(cmd_ctx, sock, sock_error, ev);
+                       if (ret) {
+                               lttng_event_destroy(ev);
+                               goto error;
+                       }
+               }
+
                ret = cmd_enable_event(cmd_ctx->session, &cmd_ctx->lsm->domain,
                                cmd_ctx->lsm->u.enable.channel_name,
-                               &cmd_ctx->lsm->u.enable.event,
+                               ev,
                                filter_expression, bytecode, exclusion,
                                kernel_poll_pipe[1]);
+               lttng_event_destroy(ev);
                break;
        }
        case LTTNG_LIST_TRACEPOINTS:
@@ -4215,15 +4346,24 @@ error_add_context:
        }
        case LTTNG_ROTATION_SET_SCHEDULE:
        {
+               bool set_schedule;
+               enum lttng_rotation_schedule_type schedule_type;
+               uint64_t value;
+
                if (cmd_ctx->session->kernel_session && !check_rotate_compatible()) {
                        DBG("Kernel tracer version does not support session rotations");
                        ret = LTTNG_ERR_ROTATION_WRONG_VERSION;
                        goto error;
                }
 
+               set_schedule = cmd_ctx->lsm->u.rotation_set_schedule.set == 1;
+               schedule_type = (enum lttng_rotation_schedule_type) cmd_ctx->lsm->u.rotation_set_schedule.type;
+               value = cmd_ctx->lsm->u.rotation_set_schedule.value;
+
                ret = cmd_rotation_set_schedule(cmd_ctx->session,
-                               cmd_ctx->lsm->u.rotate_setup.timer_us,
-                               cmd_ctx->lsm->u.rotate_setup.size,
+                               set_schedule,
+                               schedule_type,
+                               value,
                                notification_thread_handle);
                if (ret != LTTNG_OK) {
                        goto error;
@@ -4231,42 +4371,17 @@ error_add_context:
 
                break;
        }
-       case LTTNG_ROTATION_SCHEDULE_GET_TIMER_PERIOD:
-       {
-               struct lttng_rotation_schedule_get_timer_period *get_timer;
-
-               get_timer = zmalloc(sizeof(struct lttng_rotation_schedule_get_timer_period));
-               if (!get_timer) {
-                       ret = ENOMEM;
-                       goto error;
-               }
-               get_timer->rotate_timer = cmd_ctx->session->rotate_timer_period;
-
-               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, get_timer,
-                               sizeof(struct lttng_rotation_schedule_get_timer_period));
-               free(get_timer);
-               if (ret < 0) {
-                       ret = -ret;
-                       goto error;
-               }
-
-               ret = LTTNG_OK;
-               break;
-       }
-       case LTTNG_ROTATION_SCHEDULE_GET_SIZE:
+       case LTTNG_SESSION_LIST_ROTATION_SCHEDULES:
        {
-               struct lttng_rotation_schedule_get_size *get_size;
-
-               get_size = zmalloc(sizeof(struct lttng_rotation_schedule_get_size));
-               if (!get_size) {
-                       ret = ENOMEM;
-                       goto error;
-               }
-               get_size->rotate_size = cmd_ctx->session->rotate_size;
-
-               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, get_size,
-                               sizeof(struct lttng_rotation_schedule_get_size));
-               free(get_size);
+               struct lttng_session_list_schedules_return schedules = {
+                       .periodic.set = !!cmd_ctx->session->rotate_timer_period,
+                       .periodic.value = cmd_ctx->session->rotate_timer_period,
+                       .size.set = !!cmd_ctx->session->rotate_size,
+                       .size.value = cmd_ctx->session->rotate_size,
+               };
+
+               ret = setup_lttng_msg_no_cmd_header(cmd_ctx, &schedules,
+                               sizeof(schedules));
                if (ret < 0) {
                        ret = -ret;
                        goto error;
@@ -4563,8 +4678,17 @@ static void *thread_manage_clients(void *data)
                if (ret > 0 || (ret < 0 && errno != EINTR)) {
                        goto exit;
                }
-               cmm_smp_rmb();
        }
+       /*
+        * This barrier is paired with the one in sessiond_notify_ready() to
+        * ensure that loads accessing data initialized by the other threads,
+        * on which this thread was waiting, are not performed before this point.
+        *
+        * Note that this could be a 'read' memory barrier, but a full barrier
+        * is used in case the code changes. The performance implications of
+        * this choice are minimal since this is a slow path.
+        */
+       cmm_smp_mb();
 
        /* This testpoint is after we signal readiness to the parent. */
        if (testpoint(sessiond_thread_manage_clients)) {
@@ -4578,6 +4702,8 @@ static void *thread_manage_clients(void *data)
        health_code_update();
 
        while (1) {
+               const struct cmd_completion_handler *cmd_completion_handler;
+
                DBG("Accepting client command ...");
 
                /* Inifinite blocking call, waiting for transmission */
@@ -4720,6 +4846,18 @@ static void *thread_manage_clients(void *data)
                        continue;
                }
 
+               cmd_completion_handler = cmd_pop_completion_handler();
+               if (cmd_completion_handler) {
+                       enum lttng_error_code completion_code;
+
+                       completion_code = cmd_completion_handler->run(
+                                       cmd_completion_handler->data);
+                       if (completion_code != LTTNG_OK) {
+                               clean_command_ctx(&cmd_ctx);
+                               continue;
+                       }
+               }
+
                health_code_update();
 
                DBG("Sending response (size: %d, retcode: %s (%d))",
@@ -5810,6 +5948,12 @@ int main(int argc, char **argv)
                goto exit_set_signal_handler;
        }
 
+       /*
+        * Init config from environment variables.
+        * Command line option override env configuration per-doc. Do env first.
+        */
+       sessiond_config_apply_env_config(&config);
+
        /*
         * Parse arguments and load the daemon configuration file.
         *
@@ -5824,9 +5968,6 @@ int main(int argc, char **argv)
                goto exit_options;
        }
 
-       /* Init config from environment variables. */
-       sessiond_config_apply_env_config(&config);
-
        /*
         * Resolve all paths received as arguments, configuration option, or
         * through environment variable as absolute paths. This is necessary
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