#include <lttngerr.h>
#include "context.h"
+#include "futex.h"
#include "kernel-ctl.h"
#include "ltt-sessiond.h"
#include "traceable-app.h"
#include "ust-ctl.h"
#include "utils.h"
+#include "ust-comm.h"
/* Const values */
const char default_home_dir[] = DEFAULT_HOME_DIR;
static pid_t ppid; /* Parent PID for --sig-parent option */
static pid_t kconsumerd_pid;
static struct pollfd *kernel_pollfd;
+static int dispatch_thread_exit;
static char apps_unix_sock_path[PATH_MAX]; /* Global application Unix socket path */
static char client_unix_sock_path[PATH_MAX]; /* Global client Unix socket path */
*/
static int thread_quit_pipe[2];
+/*
+ * This pipe is used to inform the thread managing application communication
+ * that a command is queued and ready to be processed.
+ */
+static int apps_cmd_pipe[2];
+
/* Pthread, Mutexes and Semaphores */
static pthread_t kconsumerd_thread;
static pthread_t apps_thread;
+static pthread_t reg_apps_thread;
static pthread_t client_thread;
static pthread_t kernel_thread;
+static pthread_t dispatch_thread;
static sem_t kconsumerd_sem;
static pthread_mutex_t kconsumerd_pid_mutex; /* Mutex to control kconsumerd pid assignation */
static int modprobe_remove_kernel_modules(void);
+/*
+ * UST registration command queue. This queue is tied with a futex and uses a N
+ * wakers / 1 waiter implemented and detailed in futex.c/.h
+ *
+ * The thread_manage_apps and thread_dispatch_ust_registration interact with
+ * this queue and the wait/wake scheme.
+ */
+static struct ust_cmd_queue ust_cmd_queue;
+
/*
* Pointer initialized before thread creation.
*
}
}
+/*
+ * Stop all threads by closing the thread quit pipe.
+ */
static void stop_threads(void)
{
/* Stopping all threads */
DBG("Terminating all threads");
close(thread_quit_pipe[0]);
close(thread_quit_pipe[1]);
+ /* Dispatch thread */
+ dispatch_thread_exit = 1;
+ futex_nto1_wake(&ust_cmd_queue.futex);
}
/*
}
}
+ DBG("Closing all UST sockets");
+ clean_traceable_apps_list();
+
pthread_mutex_destroy(&kconsumerd_pid_mutex);
DBG("Closing kernel fd");
return sock;
}
-#endif /* DISABLED */
/*
* Notify apps by writing 42 to a named pipe using name. Every applications
error:
return ret;
}
+#endif /* DISABLED */
/*
* Setup the outgoing data buffer for the response (llm) by allocating the
}
/*
- * This thread manage the application socket communication
+ * Reallocate the apps command pollfd structure of nb_fd size.
+ *
+ * The first two fds must be there at all time.
+ */
+static int update_apps_cmd_pollfd(unsigned int nb_fd, struct pollfd **pollfd)
+{
+ /* Can't accept pollfd less than 2 */
+ if (nb_fd < 2) {
+ goto end;
+ }
+
+ *pollfd = realloc(*pollfd, nb_fd * sizeof(struct pollfd));
+ if (*pollfd == NULL) {
+ perror("realloc manage apps pollfd");
+ goto error;
+ }
+
+ /* First fd is always the quit pipe */
+ (*pollfd)[0].fd = thread_quit_pipe[0];
+ /* Apps command pipe */
+ (*pollfd)[1].fd = apps_cmd_pipe[0];
+ (*pollfd)[1].events = POLLIN;
+
+ DBG("Apps cmd pollfd realloc of size %d", nb_fd);
+
+end:
+ return 0;
+
+error:
+ return -1;
+}
+
+/*
+ * Send registration done packet to the application.
+ */
+static int send_ust_register_done(int sock)
+{
+ struct lttcomm_ust_msg lum;
+
+ DBG("Sending register done command to %d", sock);
+
+ lum.cmd = LTTNG_UST_REGISTER_DONE;
+ lum.handle = LTTNG_UST_ROOT_HANDLE;
+
+ return ustcomm_send_command(sock, &lum);
+}
+
+/*
+ * This thread manage application communication.
*/
static void *thread_manage_apps(void *data)
+{
+ int i, ret, count;
+ unsigned int nb_fd = 2;
+ int update_poll_flag = 1;
+ struct pollfd *pollfd = NULL;
+ struct ust_command ust_cmd;
+
+ DBG("[thread] Manage application started");
+
+ ust_cmd.sock = -1;
+
+ while (1) {
+ /* See if we have a valid socket to add to pollfd */
+ if (ust_cmd.sock != -1) {
+ nb_fd++;
+ update_poll_flag = 1;
+ }
+
+ /* The pollfd struct must be updated */
+ if (update_poll_flag) {
+ ret = update_apps_cmd_pollfd(nb_fd, &pollfd);
+ if (ret < 0) {
+ /* malloc failed so we quit */
+ goto error;
+ }
+ if (ust_cmd.sock != -1) {
+ /* Update pollfd with the new UST socket */
+ DBG("Adding sock %d to apps cmd pollfd", ust_cmd.sock);
+ pollfd[nb_fd - 1].fd = ust_cmd.sock;
+ pollfd[nb_fd - 1].events = POLLHUP | POLLNVAL;
+ ust_cmd.sock = -1;
+ }
+ }
+
+ DBG("Apps thread polling on %d fds", nb_fd);
+
+ /* Inifinite blocking call, waiting for transmission */
+ ret = poll(pollfd, nb_fd, -1);
+ if (ret < 0) {
+ perror("poll apps thread");
+ goto error;
+ }
+
+ /* Thread quit pipe has been closed. Killing thread. */
+ if (pollfd[0].revents == POLLNVAL) {
+ goto error;
+ } else if (pollfd[1].revents == POLLERR) {
+ ERR("Apps command pipe poll error");
+ goto error;
+ } else if (pollfd[1].revents == POLLIN) {
+ /* Empty pipe */
+ ret = read(apps_cmd_pipe[0], &ust_cmd, sizeof(ust_cmd));
+ if (ret < 0 || ret < sizeof(ust_cmd)) {
+ perror("read apps cmd pipe");
+ goto error;
+ }
+
+ /* Register applicaton to the session daemon */
+ ret = register_traceable_app(&ust_cmd.reg_msg, ust_cmd.sock);
+ if (ret < 0) {
+ /* Only critical ENOMEM error can be returned here */
+ goto error;
+ }
+
+ ret = send_ust_register_done(ust_cmd.sock);
+ if (ret < 0) {
+ /*
+ * If the registration is not possible, we simply unregister
+ * the apps and continue
+ */
+ unregister_traceable_app(ust_cmd.sock);
+ }
+ }
+
+ count = nb_fd;
+ for (i = 2; i < count; i++) {
+ /* Apps socket is closed/hungup */
+ switch (pollfd[i].revents) {
+ case POLLNVAL:
+ case POLLHUP:
+ /* Pipe closed */
+ unregister_traceable_app(pollfd[i].fd);
+ nb_fd--;
+ }
+ }
+
+ if (nb_fd != count) {
+ update_poll_flag = 1;
+ }
+ }
+
+error:
+ DBG("Application communication apps dying");
+ close(apps_cmd_pipe[0]);
+ close(apps_cmd_pipe[1]);
+
+ free(pollfd);
+
+ return NULL;
+}
+
+/*
+ * Dispatch request from the registration threads to the application
+ * communication thread.
+ */
+static void *thread_dispatch_ust_registration(void *data)
+{
+ int ret;
+ struct cds_wfq_node *node;
+ struct ust_command *ust_cmd = NULL;
+
+ DBG("[thread] Dispatch UST command started");
+
+ while (!dispatch_thread_exit) {
+ /* Atomically prepare the queue futex */
+ futex_nto1_prepare(&ust_cmd_queue.futex);
+
+ do {
+ /* Dequeue command for registration */
+ node = cds_wfq_dequeue_blocking(&ust_cmd_queue.queue);
+ if (node == NULL) {
+ DBG("Waked up but nothing in the UST command queue");
+ /* Continue thread execution */
+ break;
+ }
+
+ ust_cmd = caa_container_of(node, struct ust_command, node);
+
+ DBG("Dispatching UST registration pid:%d sock:%d",
+ ust_cmd->reg_msg.pid, ust_cmd->sock);
+ /*
+ * Inform apps thread of the new application registration. This
+ * call is blocking so we can be assured that the data will be read
+ * at some point in time or wait to the end of the world :)
+ */
+ ret = write(apps_cmd_pipe[1], ust_cmd,
+ sizeof(struct ust_command));
+ if (ret < 0) {
+ perror("write apps cmd pipe");
+ if (errno == EBADF) {
+ /*
+ * We can't inform the application thread to process
+ * registration. We will exit or else application
+ * registration will not occur and tracing will never
+ * start.
+ */
+ goto error;
+ }
+ }
+ free(ust_cmd);
+ } while (node != NULL);
+
+ /* Futex wait on queue. Blocking call on futex() */
+ futex_nto1_wait(&ust_cmd_queue.futex);
+ }
+
+error:
+ DBG("Dispatch thread dying");
+ return NULL;
+}
+
+/*
+ * This thread manage application registration.
+ */
+static void *thread_registration_apps(void *data)
{
int sock = 0, ret;
struct pollfd pollfd[2];
+ /*
+ * Get allocated in this thread, enqueued to a global queue, dequeued and
+ * freed in the manage apps thread.
+ */
+ struct ust_command *ust_cmd = NULL;
- /* TODO: Something more elegant is needed but fine for now */
- /* FIXME: change all types to either uint8_t, uint32_t, uint64_t
- * for 32-bit vs 64-bit compat processes. */
- /* replicate in ust with version number */
- struct {
- int reg; /* 1:register, 0:unregister */
- pid_t pid;
- uid_t uid;
- } reg_msg;
-
- DBG("[thread] Manage apps started");
+ DBG("[thread] Manage application registration started");
ret = lttcomm_listen_unix_sock(apps_sock);
if (ret < 0) {
pollfd[1].events = POLLIN;
/* Notify all applications to register */
- notify_apps(default_global_apps_pipe);
+ //notify_apps(default_global_apps_pipe);
while (1) {
DBG("Accepting application registration");
/* Inifinite blocking call, waiting for transmission */
ret = poll(pollfd, 2, -1);
if (ret < 0) {
- perror("poll apps thread");
+ perror("poll register apps thread");
goto error;
}
if (pollfd[0].revents == POLLNVAL) {
goto error;
} else if (pollfd[1].revents == POLLERR) {
- ERR("Apps socket poll error");
+ ERR("Register apps socket poll error");
goto error;
}
goto error;
}
+ /* Create UST registration command for enqueuing */
+ ust_cmd = malloc(sizeof(struct ust_command));
+ if (ust_cmd == NULL) {
+ perror("ust command malloc");
+ goto error;
+ }
+
/*
- * Using message-based transmissions to ensure we don't
- * have to deal with partially received messages.
+ * Using message-based transmissions to ensure we don't have to deal
+ * with partially received messages.
*/
- ret = lttcomm_recv_unix_sock(sock, ®_msg, sizeof(reg_msg));
- if (ret < 0) {
- perror("recv");
+ ret = lttcomm_recv_unix_sock(sock, &ust_cmd->reg_msg,
+ sizeof(struct ust_register_msg));
+ if (ret < 0 || ret != sizeof(struct ust_register_msg)) {
+ perror("lttcomm_recv_unix_sock register apps");
+ free(ust_cmd);
+ close(sock);
continue;
}
- /* Add application to the global traceable list */
- if (reg_msg.reg == 1) {
- /* Registering */
- /*
- * TODO: socket should be either passed to a
- * listener thread (for more messages) or
- * closed. It currently leaks.
- */
- ret = register_traceable_app(reg_msg.pid, reg_msg.uid);
- if (ret < 0) {
- /* register_traceable_app only return an error with
- * ENOMEM. At this point, we better stop everything.
- */
- goto error;
- }
- } else {
- /* Unregistering */
- unregister_traceable_app(reg_msg.pid);
- }
+ ust_cmd->sock = sock;
+
+ /*
+ * Lock free enqueue the registration request.
+ * The red pill has been taken! This apps will be part of the *system*
+ */
+ cds_wfq_enqueue(&ust_cmd_queue.queue, &ust_cmd->node);
+
+ /*
+ * Wake the registration queue futex.
+ * Implicit memory barrier with the exchange in cds_wfq_enqueue.
+ */
+ futex_nto1_wake(&ust_cmd_queue.futex);
+
+ DBG("Thread manage apps informed of queued node with sock:%d pid:%d",
+ sock, ust_cmd->reg_msg.pid);
}
error:
- DBG("Apps thread dying");
+ DBG("Register apps thread dying");
if (apps_sock) {
close(apps_sock);
}
static int check_existing_daemon(void)
{
if (access(client_unix_sock_path, F_OK) < 0 &&
- access(apps_unix_sock_path, F_OK) < 0)
+ access(apps_unix_sock_path, F_OK) < 0) {
return 0;
+ }
/* Is there anybody out there ? */
- if (lttng_session_daemon_alive())
+ if (lttng_session_daemon_alive()) {
return -EEXIST;
- else
+ } else {
return 0;
+ }
}
/*
return pipe2(kernel_poll_pipe, O_CLOEXEC);
}
+/*
+ * Create the application command pipe to wake thread_manage_apps.
+ */
+static int create_apps_cmd_pipe(void)
+{
+ return pipe2(apps_cmd_pipe, O_CLOEXEC);
+}
+
/*
* Create the lttng run directory needed for all global sockets and pipe.
*/
goto exit;
}
+ /* Setup the thread apps communication pipe. */
+ if ((ret = create_apps_cmd_pipe()) < 0) {
+ goto exit;
+ }
+
+ /* Init UST command queue. */
+ cds_wfq_init(&ust_cmd_queue.queue);
+
/*
* Get session list pointer. This pointer MUST NOT be free().
* This list is statically declared in session.c
session_list_ptr = get_session_list();
/* Create thread to manage the client socket */
- ret = pthread_create(&client_thread, NULL, thread_manage_clients, (void *) NULL);
+ ret = pthread_create(&client_thread, NULL,
+ thread_manage_clients, (void *) NULL);
if (ret != 0) {
- perror("pthread_create");
+ perror("pthread_create clients");
goto exit_client;
}
+ /* Create thread to dispatch registration */
+ ret = pthread_create(&dispatch_thread, NULL,
+ thread_dispatch_ust_registration, (void *) NULL);
+ if (ret != 0) {
+ perror("pthread_create dispatch");
+ goto exit_dispatch;
+ }
+
+ /* Create thread to manage application registration. */
+ ret = pthread_create(®_apps_thread, NULL,
+ thread_registration_apps, (void *) NULL);
+ if (ret != 0) {
+ perror("pthread_create registration");
+ goto exit_reg_apps;
+ }
+
/* Create thread to manage application socket */
ret = pthread_create(&apps_thread, NULL, thread_manage_apps, (void *) NULL);
if (ret != 0) {
- perror("pthread_create");
+ perror("pthread_create apps");
goto exit_apps;
}
/* Create kernel thread to manage kernel event */
ret = pthread_create(&kernel_thread, NULL, thread_manage_kernel, (void *) NULL);
if (ret != 0) {
- perror("pthread_create");
+ perror("pthread_create kernel");
goto exit_kernel;
}
}
exit_apps:
+ ret = pthread_join(reg_apps_thread, &status);
+ if (ret != 0) {
+ perror("pthread_join");
+ goto error; /* join error, exit without cleanup */
+ }
+
+exit_reg_apps:
+ ret = pthread_join(dispatch_thread, &status);
+ if (ret != 0) {
+ perror("pthread_join");
+ goto error; /* join error, exit without cleanup */
+ }
+
+exit_dispatch:
ret = pthread_join(client_thread, &status);
if (ret != 0) {
perror("pthread_join");
projects / lttng-tools.git / blobdiff