+++ /dev/null
-/*
- * lttng-ust-comm.c
- *
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
- * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; only
- * version 2.1 of the License.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
-
-#define _LGPL_SOURCE
-#define _GNU_SOURCE
-#include <sys/types.h>
-#include <sys/socket.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <sys/wait.h>
-#include <dlfcn.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <errno.h>
-#include <pthread.h>
-#include <semaphore.h>
-#include <time.h>
-#include <assert.h>
-#include <signal.h>
-#include <limits.h>
-#include <urcu/uatomic.h>
-#include <urcu/futex.h>
-#include <urcu/compiler.h>
-
-#include <lttng/ust-events.h>
-#include <lttng/ust-abi.h>
-#include <lttng/ust.h>
-#include <lttng/ust-error.h>
-#include <lttng/ust-ctl.h>
-#include <urcu/tls-compat.h>
-#include <ust-comm.h>
-#include <ust-fd.h>
-#include <usterr-signal-safe.h>
-#include <helper.h>
-#include "tracepoint-internal.h"
-#include "lttng-tracer-core.h"
-#include "compat.h"
-#include "../libringbuffer/rb-init.h"
-#include "lttng-ust-statedump.h"
-#include "clock.h"
-#include "../libringbuffer/getcpu.h"
-#include "getenv.h"
-
-/* Concatenate lttng ust shared library name with its major version number. */
-#define LTTNG_UST_LIB_SO_NAME "liblttng-ust.so." __ust_stringify(CONFIG_LTTNG_UST_LIBRARY_VERSION_MAJOR)
-
-/*
- * Has lttng ust comm constructor been called ?
- */
-static int initialized;
-
-/*
- * The ust_lock/ust_unlock lock is used as a communication thread mutex.
- * Held when handling a command, also held by fork() to deal with
- * removal of threads, and by exit path.
- *
- * The UST lock is the centralized mutex across UST tracing control and
- * probe registration.
- *
- * ust_exit_mutex must never nest in ust_mutex.
- *
- * ust_fork_mutex must never nest in ust_mutex.
- *
- * ust_mutex_nest is a per-thread nesting counter, allowing the perf
- * counter lazy initialization called by events within the statedump,
- * which traces while the ust_mutex is held.
- *
- * ust_lock nests within the dynamic loader lock (within glibc) because
- * it is taken within the library constructor.
- *
- * The ust fd tracker lock nests within the ust_mutex.
- */
-static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-/* Allow nesting the ust_mutex within the same thread. */
-static DEFINE_URCU_TLS(int, ust_mutex_nest);
-
-/*
- * ust_exit_mutex protects thread_active variable wrt thread exit. It
- * cannot be done by ust_mutex because pthread_cancel(), which takes an
- * internal libc lock, cannot nest within ust_mutex.
- *
- * It never nests within a ust_mutex.
- */
-static pthread_mutex_t ust_exit_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-/*
- * ust_fork_mutex protects base address statedump tracing against forks. It
- * prevents the dynamic loader lock to be taken (by base address statedump
- * tracing) while a fork is happening, thus preventing deadlock issues with
- * the dynamic loader lock.
- */
-static pthread_mutex_t ust_fork_mutex = PTHREAD_MUTEX_INITIALIZER;
-
-/* Should the ust comm thread quit ? */
-static int lttng_ust_comm_should_quit;
-
-/*
- * This variable can be tested by applications to check whether
- * lttng-ust is loaded. They simply have to define their own
- * "lttng_ust_loaded" weak symbol, and test it. It is set to 1 by the
- * library constructor.
- */
-int lttng_ust_loaded __attribute__((weak));
-
-/*
- * Return 0 on success, -1 if should quit.
- * The lock is taken in both cases.
- * Signal-safe.
- */
-int ust_lock(void)
-{
- sigset_t sig_all_blocked, orig_mask;
- int ret, oldstate;
-
- ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
- if (ret) {
- ERR("pthread_setcancelstate: %s", strerror(ret));
- }
- if (oldstate != PTHREAD_CANCEL_ENABLE) {
- ERR("pthread_setcancelstate: unexpected oldstate");
- }
- sigfillset(&sig_all_blocked);
- ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
- if (!URCU_TLS(ust_mutex_nest)++)
- pthread_mutex_lock(&ust_mutex);
- ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
- if (lttng_ust_comm_should_quit) {
- return -1;
- } else {
- return 0;
- }
-}
-
-/*
- * ust_lock_nocheck() can be used in constructors/destructors, because
- * they are already nested within the dynamic loader lock, and therefore
- * have exclusive access against execution of liblttng-ust destructor.
- * Signal-safe.
- */
-void ust_lock_nocheck(void)
-{
- sigset_t sig_all_blocked, orig_mask;
- int ret, oldstate;
-
- ret = pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &oldstate);
- if (ret) {
- ERR("pthread_setcancelstate: %s", strerror(ret));
- }
- if (oldstate != PTHREAD_CANCEL_ENABLE) {
- ERR("pthread_setcancelstate: unexpected oldstate");
- }
- sigfillset(&sig_all_blocked);
- ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
- if (!URCU_TLS(ust_mutex_nest)++)
- pthread_mutex_lock(&ust_mutex);
- ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
-}
-
-/*
- * Signal-safe.
- */
-void ust_unlock(void)
-{
- sigset_t sig_all_blocked, orig_mask;
- int ret, oldstate;
-
- sigfillset(&sig_all_blocked);
- ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
- if (!--URCU_TLS(ust_mutex_nest))
- pthread_mutex_unlock(&ust_mutex);
- ret = pthread_sigmask(SIG_SETMASK, &orig_mask, NULL);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
- ret = pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, &oldstate);
- if (ret) {
- ERR("pthread_setcancelstate: %s", strerror(ret));
- }
- if (oldstate != PTHREAD_CANCEL_DISABLE) {
- ERR("pthread_setcancelstate: unexpected oldstate");
- }
-}
-
-/*
- * Wait for either of these before continuing to the main
- * program:
- * - the register_done message from sessiond daemon
- * (will let the sessiond daemon enable sessions before main
- * starts.)
- * - sessiond daemon is not reachable.
- * - timeout (ensuring applications are resilient to session
- * daemon problems).
- */
-static sem_t constructor_wait;
-/*
- * Doing this for both the global and local sessiond.
- */
-enum {
- sem_count_initial_value = 4,
-};
-
-static int sem_count = sem_count_initial_value;
-
-/*
- * Counting nesting within lttng-ust. Used to ensure that calling fork()
- * from liblttng-ust does not execute the pre/post fork handlers.
- */
-static DEFINE_URCU_TLS(int, lttng_ust_nest_count);
-
-/*
- * Info about socket and associated listener thread.
- */
-struct sock_info {
- const char *name;
- pthread_t ust_listener; /* listener thread */
- int root_handle;
- int registration_done;
- int allowed;
- int global;
- int thread_active;
-
- char sock_path[PATH_MAX];
- int socket;
- int notify_socket;
-
- char wait_shm_path[PATH_MAX];
- char *wait_shm_mmap;
- /* Keep track of lazy state dump not performed yet. */
- int statedump_pending;
- int initial_statedump_done;
-};
-
-/* Socket from app (connect) to session daemon (listen) for communication */
-struct sock_info global_apps = {
- .name = "global",
- .global = 1,
-
- .root_handle = -1,
- .registration_done = 0,
- .allowed = 0,
- .thread_active = 0,
-
- .sock_path = LTTNG_DEFAULT_RUNDIR "/" LTTNG_UST_SOCK_FILENAME,
- .socket = -1,
- .notify_socket = -1,
-
- .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
-
- .statedump_pending = 0,
- .initial_statedump_done = 0,
-};
-
-/* TODO: allow global_apps_sock_path override */
-
-struct sock_info local_apps = {
- .name = "local",
- .global = 0,
- .root_handle = -1,
- .registration_done = 0,
- .allowed = 0, /* Check setuid bit first */
- .thread_active = 0,
-
- .socket = -1,
- .notify_socket = -1,
-
- .statedump_pending = 0,
- .initial_statedump_done = 0,
-};
-
-static int wait_poll_fallback;
-
-static const char *cmd_name_mapping[] = {
- [ LTTNG_UST_RELEASE ] = "Release",
- [ LTTNG_UST_SESSION ] = "Create Session",
- [ LTTNG_UST_TRACER_VERSION ] = "Get Tracer Version",
-
- [ LTTNG_UST_TRACEPOINT_LIST ] = "Create Tracepoint List",
- [ LTTNG_UST_WAIT_QUIESCENT ] = "Wait for Quiescent State",
- [ LTTNG_UST_REGISTER_DONE ] = "Registration Done",
- [ LTTNG_UST_TRACEPOINT_FIELD_LIST ] = "Create Tracepoint Field List",
-
- /* Session FD commands */
- [ LTTNG_UST_CHANNEL ] = "Create Channel",
- [ LTTNG_UST_SESSION_START ] = "Start Session",
- [ LTTNG_UST_SESSION_STOP ] = "Stop Session",
-
- /* Channel FD commands */
- [ LTTNG_UST_STREAM ] = "Create Stream",
- [ LTTNG_UST_EVENT ] = "Create Event",
-
- /* Event and Channel FD commands */
- [ LTTNG_UST_CONTEXT ] = "Create Context",
- [ LTTNG_UST_FLUSH_BUFFER ] = "Flush Buffer",
-
- /* Event, Channel and Session commands */
- [ LTTNG_UST_ENABLE ] = "Enable",
- [ LTTNG_UST_DISABLE ] = "Disable",
-
- /* Tracepoint list commands */
- [ LTTNG_UST_TRACEPOINT_LIST_GET ] = "List Next Tracepoint",
- [ LTTNG_UST_TRACEPOINT_FIELD_LIST_GET ] = "List Next Tracepoint Field",
-
- /* Event FD commands */
- [ LTTNG_UST_FILTER ] = "Create Filter",
- [ LTTNG_UST_EXCLUSION ] = "Add exclusions to event",
-};
-
-static const char *str_timeout;
-static int got_timeout_env;
-
-extern void lttng_ring_buffer_client_overwrite_init(void);
-extern void lttng_ring_buffer_client_overwrite_rt_init(void);
-extern void lttng_ring_buffer_client_discard_init(void);
-extern void lttng_ring_buffer_client_discard_rt_init(void);
-extern void lttng_ring_buffer_metadata_client_init(void);
-extern void lttng_ring_buffer_client_overwrite_exit(void);
-extern void lttng_ring_buffer_client_overwrite_rt_exit(void);
-extern void lttng_ring_buffer_client_discard_exit(void);
-extern void lttng_ring_buffer_client_discard_rt_exit(void);
-extern void lttng_ring_buffer_metadata_client_exit(void);
-
-static char *get_map_shm(struct sock_info *sock_info);
-
-ssize_t lttng_ust_read(int fd, void *buf, size_t len)
-{
- ssize_t ret;
- size_t copied = 0, to_copy = len;
-
- do {
- ret = read(fd, buf + copied, to_copy);
- if (ret > 0) {
- copied += ret;
- to_copy -= ret;
- }
- } while ((ret > 0 && to_copy > 0)
- || (ret < 0 && errno == EINTR));
- if (ret > 0) {
- ret = copied;
- }
- return ret;
-}
-/*
- * Returns the HOME directory path. Caller MUST NOT free(3) the returned
- * pointer.
- */
-static
-const char *get_lttng_home_dir(void)
-{
- const char *val;
-
- val = (const char *) lttng_getenv("LTTNG_HOME");
- if (val != NULL) {
- return val;
- }
- return (const char *) lttng_getenv("HOME");
-}
-
-/*
- * Force a read (imply TLS fixup for dlopen) of TLS variables.
- */
-static
-void lttng_fixup_nest_count_tls(void)
-{
- asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count)));
-}
-
-static
-void lttng_fixup_ust_mutex_nest_tls(void)
-{
- asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest)));
-}
-
-/*
- * Fixup urcu bp TLS.
- */
-static
-void lttng_fixup_urcu_bp_tls(void)
-{
- rcu_read_lock();
- rcu_read_unlock();
-}
-
-void lttng_ust_fixup_tls(void)
-{
- lttng_fixup_urcu_bp_tls();
- lttng_fixup_ringbuffer_tls();
- lttng_fixup_vtid_tls();
- lttng_fixup_nest_count_tls();
- lttng_fixup_procname_tls();
- lttng_fixup_ust_mutex_nest_tls();
- lttng_ust_fixup_perf_counter_tls();
- lttng_ust_fixup_fd_tracker_tls();
-}
-
-int lttng_get_notify_socket(void *owner)
-{
- struct sock_info *info = owner;
-
- return info->notify_socket;
-}
-
-static
-void print_cmd(int cmd, int handle)
-{
- const char *cmd_name = "Unknown";
-
- if (cmd >= 0 && cmd < LTTNG_ARRAY_SIZE(cmd_name_mapping)
- && cmd_name_mapping[cmd]) {
- cmd_name = cmd_name_mapping[cmd];
- }
- DBG("Message Received \"%s\" (%d), Handle \"%s\" (%d)",
- cmd_name, cmd,
- lttng_ust_obj_get_name(handle), handle);
-}
-
-static
-int setup_global_apps(void)
-{
- int ret = 0;
- assert(!global_apps.wait_shm_mmap);
-
- global_apps.wait_shm_mmap = get_map_shm(&global_apps);
- if (!global_apps.wait_shm_mmap) {
- WARN("Unable to get map shm for global apps. Disabling LTTng-UST global tracing.");
- global_apps.allowed = 0;
- ret = -EIO;
- goto error;
- }
-
- global_apps.allowed = 1;
-error:
- return ret;
-}
-static
-int setup_local_apps(void)
-{
- int ret = 0;
- const char *home_dir;
- uid_t uid;
-
- assert(!local_apps.wait_shm_mmap);
-
- uid = getuid();
- /*
- * Disallow per-user tracing for setuid binaries.
- */
- if (uid != geteuid()) {
- assert(local_apps.allowed == 0);
- ret = 0;
- goto end;
- }
- home_dir = get_lttng_home_dir();
- if (!home_dir) {
- WARN("HOME environment variable not set. Disabling LTTng-UST per-user tracing.");
- assert(local_apps.allowed == 0);
- ret = -ENOENT;
- goto end;
- }
- local_apps.allowed = 1;
- snprintf(local_apps.sock_path, PATH_MAX, "%s/%s/%s",
- home_dir,
- LTTNG_DEFAULT_HOME_RUNDIR,
- LTTNG_UST_SOCK_FILENAME);
- snprintf(local_apps.wait_shm_path, PATH_MAX, "/%s-%u",
- LTTNG_UST_WAIT_FILENAME,
- uid);
-
- local_apps.wait_shm_mmap = get_map_shm(&local_apps);
- if (!local_apps.wait_shm_mmap) {
- WARN("Unable to get map shm for local apps. Disabling LTTng-UST per-user tracing.");
- local_apps.allowed = 0;
- ret = -EIO;
- goto end;
- }
-end:
- return ret;
-}
-
-/*
- * Get socket timeout, in ms.
- * -1: wait forever. 0: don't wait. >0: timeout, in ms.
- */
-static
-long get_timeout(void)
-{
- long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS;
-
- if (!got_timeout_env) {
- str_timeout = lttng_getenv("LTTNG_UST_REGISTER_TIMEOUT");
- got_timeout_env = 1;
- }
- if (str_timeout)
- constructor_delay_ms = strtol(str_timeout, NULL, 10);
- /* All negative values are considered as "-1". */
- if (constructor_delay_ms < -1)
- constructor_delay_ms = -1;
- return constructor_delay_ms;
-}
-
-/* Timeout for notify socket send and recv. */
-static
-long get_notify_sock_timeout(void)
-{
- return get_timeout();
-}
-
-/* Timeout for connecting to cmd and notify sockets. */
-static
-long get_connect_sock_timeout(void)
-{
- return get_timeout();
-}
-
-/*
- * Return values: -1: wait forever. 0: don't wait. 1: timeout wait.
- */
-static
-int get_constructor_timeout(struct timespec *constructor_timeout)
-{
- long constructor_delay_ms;
- int ret;
-
- constructor_delay_ms = get_timeout();
-
- switch (constructor_delay_ms) {
- case -1:/* fall-through */
- case 0:
- return constructor_delay_ms;
- default:
- break;
- }
-
- /*
- * If we are unable to find the current time, don't wait.
- */
- ret = clock_gettime(CLOCK_REALTIME, constructor_timeout);
- if (ret) {
- /* Don't wait. */
- return 0;
- }
- constructor_timeout->tv_sec += constructor_delay_ms / 1000UL;
- constructor_timeout->tv_nsec +=
- (constructor_delay_ms % 1000UL) * 1000000UL;
- if (constructor_timeout->tv_nsec >= 1000000000UL) {
- constructor_timeout->tv_sec++;
- constructor_timeout->tv_nsec -= 1000000000UL;
- }
- /* Timeout wait (constructor_delay_ms). */
- return 1;
-}
-
-static
-void get_allow_blocking(void)
-{
- const char *str_allow_blocking =
- lttng_getenv("LTTNG_UST_ALLOW_BLOCKING");
-
- if (str_allow_blocking) {
- DBG("%s environment variable is set",
- "LTTNG_UST_ALLOW_BLOCKING");
- lttng_ust_ringbuffer_set_allow_blocking();
- }
-}
-
-static
-int register_to_sessiond(int socket, enum ustctl_socket_type type)
-{
- return ustcomm_send_reg_msg(socket,
- type,
- CAA_BITS_PER_LONG,
- lttng_alignof(uint8_t) * CHAR_BIT,
- lttng_alignof(uint16_t) * CHAR_BIT,
- lttng_alignof(uint32_t) * CHAR_BIT,
- lttng_alignof(uint64_t) * CHAR_BIT,
- lttng_alignof(unsigned long) * CHAR_BIT);
-}
-
-static
-int send_reply(int sock, struct ustcomm_ust_reply *lur)
-{
- ssize_t len;
-
- len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur));
- switch (len) {
- case sizeof(*lur):
- DBG("message successfully sent");
- return 0;
- default:
- if (len == -ECONNRESET) {
- DBG("remote end closed connection");
- return 0;
- }
- if (len < 0)
- return len;
- DBG("incorrect message size: %zd", len);
- return -EINVAL;
- }
-}
-
-static
-void decrement_sem_count(unsigned int count)
-{
- int ret;
-
- assert(uatomic_read(&sem_count) >= count);
-
- if (uatomic_read(&sem_count) <= 0) {
- return;
- }
-
- ret = uatomic_add_return(&sem_count, -count);
- if (ret == 0) {
- ret = sem_post(&constructor_wait);
- assert(!ret);
- }
-}
-
-static
-int handle_register_done(struct sock_info *sock_info)
-{
- if (sock_info->registration_done)
- return 0;
- sock_info->registration_done = 1;
-
- decrement_sem_count(1);
- if (!sock_info->statedump_pending) {
- sock_info->initial_statedump_done = 1;
- decrement_sem_count(1);
- }
-
- return 0;
-}
-
-static
-int handle_register_failed(struct sock_info *sock_info)
-{
- if (sock_info->registration_done)
- return 0;
- sock_info->registration_done = 1;
- sock_info->initial_statedump_done = 1;
-
- decrement_sem_count(2);
-
- return 0;
-}
-
-/*
- * Only execute pending statedump after the constructor semaphore has
- * been posted by the current listener thread. This means statedump will
- * only be performed after the "registration done" command is received
- * from this thread's session daemon.
- *
- * This ensures we don't run into deadlock issues with the dynamic
- * loader mutex, which is held while the constructor is called and
- * waiting on the constructor semaphore. All operations requiring this
- * dynamic loader lock need to be postponed using this mechanism.
- *
- * In a scenario with two session daemons connected to the application,
- * it is possible that the first listener thread which receives the
- * registration done command issues its statedump while the dynamic
- * loader lock is still held by the application constructor waiting on
- * the semaphore. It will however be allowed to proceed when the
- * second session daemon sends the registration done command to the
- * second listener thread. This situation therefore does not produce
- * a deadlock.
- */
-static
-void handle_pending_statedump(struct sock_info *sock_info)
-{
- if (sock_info->registration_done && sock_info->statedump_pending) {
- sock_info->statedump_pending = 0;
- pthread_mutex_lock(&ust_fork_mutex);
- lttng_handle_pending_statedump(sock_info);
- pthread_mutex_unlock(&ust_fork_mutex);
-
- if (!sock_info->initial_statedump_done) {
- sock_info->initial_statedump_done = 1;
- decrement_sem_count(1);
- }
- }
-}
-
-static
-int handle_message(struct sock_info *sock_info,
- int sock, struct ustcomm_ust_msg *lum)
-{
- int ret = 0;
- const struct lttng_ust_objd_ops *ops;
- struct ustcomm_ust_reply lur;
- union ust_args args;
- char ctxstr[LTTNG_UST_SYM_NAME_LEN]; /* App context string. */
- ssize_t len;
-
- memset(&lur, 0, sizeof(lur));
-
- if (ust_lock()) {
- ret = -LTTNG_UST_ERR_EXITING;
- goto error;
- }
-
- ops = objd_ops(lum->handle);
- if (!ops) {
- ret = -ENOENT;
- goto error;
- }
-
- switch (lum->cmd) {
- case LTTNG_UST_REGISTER_DONE:
- if (lum->handle == LTTNG_UST_ROOT_HANDLE)
- ret = handle_register_done(sock_info);
- else
- ret = -EINVAL;
- break;
- case LTTNG_UST_RELEASE:
- if (lum->handle == LTTNG_UST_ROOT_HANDLE)
- ret = -EPERM;
- else
- ret = lttng_ust_objd_unref(lum->handle, 1);
- break;
- case LTTNG_UST_FILTER:
- {
- /* Receive filter data */
- struct lttng_ust_filter_bytecode_node *bytecode;
-
- if (lum->u.filter.data_size > FILTER_BYTECODE_MAX_LEN) {
- ERR("Filter data size is too large: %u bytes",
- lum->u.filter.data_size);
- ret = -EINVAL;
- goto error;
- }
-
- if (lum->u.filter.reloc_offset > lum->u.filter.data_size) {
- ERR("Filter reloc offset %u is not within data",
- lum->u.filter.reloc_offset);
- ret = -EINVAL;
- goto error;
- }
-
- bytecode = zmalloc(sizeof(*bytecode) + lum->u.filter.data_size);
- if (!bytecode) {
- ret = -ENOMEM;
- goto error;
- }
- len = ustcomm_recv_unix_sock(sock, bytecode->bc.data,
- lum->u.filter.data_size);
- switch (len) {
- case 0: /* orderly shutdown */
- ret = 0;
- free(bytecode);
- goto error;
- default:
- if (len == lum->u.filter.data_size) {
- DBG("filter data received");
- break;
- } else if (len < 0) {
- DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
- if (len == -ECONNRESET) {
- ERR("%s remote end closed connection", sock_info->name);
- ret = len;
- free(bytecode);
- goto error;
- }
- ret = len;
- free(bytecode);
- goto error;
- } else {
- DBG("incorrect filter data message size: %zd", len);
- ret = -EINVAL;
- free(bytecode);
- goto error;
- }
- }
- bytecode->bc.len = lum->u.filter.data_size;
- bytecode->bc.reloc_offset = lum->u.filter.reloc_offset;
- bytecode->bc.seqnum = lum->u.filter.seqnum;
- if (ops->cmd) {
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) bytecode,
- &args, sock_info);
- if (ret) {
- free(bytecode);
- }
- /* don't free bytecode if everything went fine. */
- } else {
- ret = -ENOSYS;
- free(bytecode);
- }
- break;
- }
- case LTTNG_UST_EXCLUSION:
- {
- /* Receive exclusion names */
- struct lttng_ust_excluder_node *node;
- unsigned int count;
-
- count = lum->u.exclusion.count;
- if (count == 0) {
- /* There are no names to read */
- ret = 0;
- goto error;
- }
- node = zmalloc(sizeof(*node) +
- count * LTTNG_UST_SYM_NAME_LEN);
- if (!node) {
- ret = -ENOMEM;
- goto error;
- }
- node->excluder.count = count;
- len = ustcomm_recv_unix_sock(sock, node->excluder.names,
- count * LTTNG_UST_SYM_NAME_LEN);
- switch (len) {
- case 0: /* orderly shutdown */
- ret = 0;
- free(node);
- goto error;
- default:
- if (len == count * LTTNG_UST_SYM_NAME_LEN) {
- DBG("Exclusion data received");
- break;
- } else if (len < 0) {
- DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
- if (len == -ECONNRESET) {
- ERR("%s remote end closed connection", sock_info->name);
- ret = len;
- free(node);
- goto error;
- }
- ret = len;
- free(node);
- goto error;
- } else {
- DBG("Incorrect exclusion data message size: %zd", len);
- ret = -EINVAL;
- free(node);
- goto error;
- }
- }
- if (ops->cmd) {
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) node,
- &args, sock_info);
- if (ret) {
- free(node);
- }
- /* Don't free exclusion data if everything went fine. */
- } else {
- ret = -ENOSYS;
- free(node);
- }
- break;
- }
- case LTTNG_UST_CHANNEL:
- {
- void *chan_data;
- int wakeup_fd;
-
- len = ustcomm_recv_channel_from_sessiond(sock,
- &chan_data, lum->u.channel.len,
- &wakeup_fd);
- switch (len) {
- case 0: /* orderly shutdown */
- ret = 0;
- goto error;
- default:
- if (len == lum->u.channel.len) {
- DBG("channel data received");
- break;
- } else if (len < 0) {
- DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
- if (len == -ECONNRESET) {
- ERR("%s remote end closed connection", sock_info->name);
- ret = len;
- goto error;
- }
- ret = len;
- goto error;
- } else {
- DBG("incorrect channel data message size: %zd", len);
- ret = -EINVAL;
- goto error;
- }
- }
- args.channel.chan_data = chan_data;
- args.channel.wakeup_fd = wakeup_fd;
- if (ops->cmd)
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) &lum->u,
- &args, sock_info);
- else
- ret = -ENOSYS;
- break;
- }
- case LTTNG_UST_STREAM:
- {
- /* Receive shm_fd, wakeup_fd */
- ret = ustcomm_recv_stream_from_sessiond(sock,
- NULL,
- &args.stream.shm_fd,
- &args.stream.wakeup_fd);
- if (ret) {
- goto error;
- }
-
- if (ops->cmd)
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) &lum->u,
- &args, sock_info);
- else
- ret = -ENOSYS;
- break;
- }
- case LTTNG_UST_CONTEXT:
- switch (lum->u.context.ctx) {
- case LTTNG_UST_CONTEXT_APP_CONTEXT:
- {
- char *p;
- size_t ctxlen, recvlen;
-
- ctxlen = strlen("$app.") + lum->u.context.u.app_ctx.provider_name_len - 1
- + strlen(":") + lum->u.context.u.app_ctx.ctx_name_len;
- if (ctxlen >= LTTNG_UST_SYM_NAME_LEN) {
- ERR("Application context string length size is too large: %zu bytes",
- ctxlen);
- ret = -EINVAL;
- goto error;
- }
- strcpy(ctxstr, "$app.");
- p = &ctxstr[strlen("$app.")];
- recvlen = ctxlen - strlen("$app.");
- len = ustcomm_recv_unix_sock(sock, p, recvlen);
- switch (len) {
- case 0: /* orderly shutdown */
- ret = 0;
- goto error;
- default:
- if (len == recvlen) {
- DBG("app context data received");
- break;
- } else if (len < 0) {
- DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
- if (len == -ECONNRESET) {
- ERR("%s remote end closed connection", sock_info->name);
- ret = len;
- goto error;
- }
- ret = len;
- goto error;
- } else {
- DBG("incorrect app context data message size: %zd", len);
- ret = -EINVAL;
- goto error;
- }
- }
- /* Put : between provider and ctxname. */
- p[lum->u.context.u.app_ctx.provider_name_len - 1] = ':';
- args.app_context.ctxname = ctxstr;
- break;
- }
- default:
- break;
- }
- if (ops->cmd) {
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) &lum->u,
- &args, sock_info);
- } else {
- ret = -ENOSYS;
- }
- break;
- default:
- if (ops->cmd)
- ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) &lum->u,
- &args, sock_info);
- else
- ret = -ENOSYS;
- break;
- }
-
- lur.handle = lum->handle;
- lur.cmd = lum->cmd;
- lur.ret_val = ret;
- if (ret >= 0) {
- lur.ret_code = LTTNG_UST_OK;
- } else {
- /*
- * Use -LTTNG_UST_ERR as wildcard for UST internal
- * error that are not caused by the transport, except if
- * we already have a more precise error message to
- * report.
- */
- if (ret > -LTTNG_UST_ERR) {
- /* Translate code to UST error. */
- switch (ret) {
- case -EEXIST:
- lur.ret_code = -LTTNG_UST_ERR_EXIST;
- break;
- case -EINVAL:
- lur.ret_code = -LTTNG_UST_ERR_INVAL;
- break;
- case -ENOENT:
- lur.ret_code = -LTTNG_UST_ERR_NOENT;
- break;
- case -EPERM:
- lur.ret_code = -LTTNG_UST_ERR_PERM;
- break;
- case -ENOSYS:
- lur.ret_code = -LTTNG_UST_ERR_NOSYS;
- break;
- default:
- lur.ret_code = -LTTNG_UST_ERR;
- break;
- }
- } else {
- lur.ret_code = ret;
- }
- }
- if (ret >= 0) {
- switch (lum->cmd) {
- case LTTNG_UST_TRACER_VERSION:
- lur.u.version = lum->u.version;
- break;
- case LTTNG_UST_TRACEPOINT_LIST_GET:
- memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint));
- break;
- }
- }
- DBG("Return value: %d", lur.ret_val);
-
- ust_unlock();
-
- /*
- * Performed delayed statedump operations outside of the UST
- * lock. We need to take the dynamic loader lock before we take
- * the UST lock internally within handle_pending_statedump().
- */
- handle_pending_statedump(sock_info);
-
- if (ust_lock()) {
- ret = -LTTNG_UST_ERR_EXITING;
- goto error;
- }
-
- ret = send_reply(sock, &lur);
- if (ret < 0) {
- DBG("error sending reply");
- goto error;
- }
-
- /*
- * LTTNG_UST_TRACEPOINT_FIELD_LIST_GET needs to send the field
- * after the reply.
- */
- if (lur.ret_code == LTTNG_UST_OK) {
- switch (lum->cmd) {
- case LTTNG_UST_TRACEPOINT_FIELD_LIST_GET:
- len = ustcomm_send_unix_sock(sock,
- &args.field_list.entry,
- sizeof(args.field_list.entry));
- if (len < 0) {
- ret = len;
- goto error;
- }
- if (len != sizeof(args.field_list.entry)) {
- ret = -EINVAL;
- goto error;
- }
- }
- }
-
-error:
- ust_unlock();
-
- return ret;
-}
-
-static
-void cleanup_sock_info(struct sock_info *sock_info, int exiting)
-{
- int ret;
-
- if (sock_info->root_handle != -1) {
- ret = lttng_ust_objd_unref(sock_info->root_handle, 1);
- if (ret) {
- ERR("Error unref root handle");
- }
- sock_info->root_handle = -1;
- }
- sock_info->registration_done = 0;
- sock_info->initial_statedump_done = 0;
-
- /*
- * wait_shm_mmap, socket and notify socket are used by listener
- * threads outside of the ust lock, so we cannot tear them down
- * ourselves, because we cannot join on these threads. Leave
- * responsibility of cleaning up these resources to the OS
- * process exit.
- */
- if (exiting)
- return;
-
- if (sock_info->socket != -1) {
- ret = ustcomm_close_unix_sock(sock_info->socket);
- if (ret) {
- ERR("Error closing ust cmd socket");
- }
- sock_info->socket = -1;
- }
- if (sock_info->notify_socket != -1) {
- ret = ustcomm_close_unix_sock(sock_info->notify_socket);
- if (ret) {
- ERR("Error closing ust notify socket");
- }
- sock_info->notify_socket = -1;
- }
- if (sock_info->wait_shm_mmap) {
- long page_size;
-
- page_size = sysconf(_SC_PAGE_SIZE);
- if (page_size <= 0) {
- if (!page_size) {
- errno = EINVAL;
- }
- PERROR("Error in sysconf(_SC_PAGE_SIZE)");
- } else {
- ret = munmap(sock_info->wait_shm_mmap, page_size);
- if (ret) {
- ERR("Error unmapping wait shm");
- }
- }
- sock_info->wait_shm_mmap = NULL;
- }
-}
-
-/*
- * Using fork to set umask in the child process (not multi-thread safe).
- * We deal with the shm_open vs ftruncate race (happening when the
- * sessiond owns the shm and does not let everybody modify it, to ensure
- * safety against shm_unlink) by simply letting the mmap fail and
- * retrying after a few seconds.
- * For global shm, everybody has rw access to it until the sessiond
- * starts.
- */
-static
-int get_wait_shm(struct sock_info *sock_info, size_t mmap_size)
-{
- int wait_shm_fd, ret;
- pid_t pid;
-
- /*
- * Try to open read-only.
- */
- wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0);
- if (wait_shm_fd >= 0) {
- int32_t tmp_read;
- ssize_t len;
- size_t bytes_read = 0;
-
- /*
- * Try to read the fd. If unable to do so, try opening
- * it in write mode.
- */
- do {
- len = read(wait_shm_fd,
- &((char *) &tmp_read)[bytes_read],
- sizeof(tmp_read) - bytes_read);
- if (len > 0) {
- bytes_read += len;
- }
- } while ((len < 0 && errno == EINTR)
- || (len > 0 && bytes_read < sizeof(tmp_read)));
- if (bytes_read != sizeof(tmp_read)) {
- ret = close(wait_shm_fd);
- if (ret) {
- ERR("close wait_shm_fd");
- }
- goto open_write;
- }
- goto end;
- } else if (wait_shm_fd < 0 && errno != ENOENT) {
- /*
- * Real-only open did not work, and it's not because the
- * entry was not present. It's a failure that prohibits
- * using shm.
- */
- ERR("Error opening shm %s", sock_info->wait_shm_path);
- goto end;
- }
-
-open_write:
- /*
- * If the open failed because the file did not exist, or because
- * the file was not truncated yet, try creating it ourself.
- */
- URCU_TLS(lttng_ust_nest_count)++;
- pid = fork();
- URCU_TLS(lttng_ust_nest_count)--;
- if (pid > 0) {
- int status;
-
- /*
- * Parent: wait for child to return, in which case the
- * shared memory map will have been created.
- */
- pid = wait(&status);
- if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
- wait_shm_fd = -1;
- goto end;
- }
- /*
- * Try to open read-only again after creation.
- */
- wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0);
- if (wait_shm_fd < 0) {
- /*
- * Real-only open did not work. It's a failure
- * that prohibits using shm.
- */
- ERR("Error opening shm %s", sock_info->wait_shm_path);
- goto end;
- }
- goto end;
- } else if (pid == 0) {
- int create_mode;
-
- /* Child */
- create_mode = S_IRUSR | S_IWUSR | S_IRGRP;
- if (sock_info->global)
- create_mode |= S_IROTH | S_IWGRP | S_IWOTH;
- /*
- * We're alone in a child process, so we can modify the
- * process-wide umask.
- */
- umask(~create_mode);
- /*
- * Try creating shm (or get rw access).
- * We don't do an exclusive open, because we allow other
- * processes to create+ftruncate it concurrently.
- */
- wait_shm_fd = shm_open(sock_info->wait_shm_path,
- O_RDWR | O_CREAT, create_mode);
- if (wait_shm_fd >= 0) {
- ret = ftruncate(wait_shm_fd, mmap_size);
- if (ret) {
- PERROR("ftruncate");
- _exit(EXIT_FAILURE);
- }
- _exit(EXIT_SUCCESS);
- }
- /*
- * For local shm, we need to have rw access to accept
- * opening it: this means the local sessiond will be
- * able to wake us up. For global shm, we open it even
- * if rw access is not granted, because the root.root
- * sessiond will be able to override all rights and wake
- * us up.
- */
- if (!sock_info->global && errno != EACCES) {
- ERR("Error opening shm %s", sock_info->wait_shm_path);
- _exit(EXIT_FAILURE);
- }
- /*
- * The shm exists, but we cannot open it RW. Report
- * success.
- */
- _exit(EXIT_SUCCESS);
- } else {
- return -1;
- }
-end:
- if (wait_shm_fd >= 0 && !sock_info->global) {
- struct stat statbuf;
-
- /*
- * Ensure that our user is the owner of the shm file for
- * local shm. If we do not own the file, it means our
- * sessiond will not have access to wake us up (there is
- * probably a rogue process trying to fake our
- * sessiond). Fallback to polling method in this case.
- */
- ret = fstat(wait_shm_fd, &statbuf);
- if (ret) {
- PERROR("fstat");
- goto error_close;
- }
- if (statbuf.st_uid != getuid())
- goto error_close;
- }
- return wait_shm_fd;
-
-error_close:
- ret = close(wait_shm_fd);
- if (ret) {
- PERROR("Error closing fd");
- }
- return -1;
-}
-
-static
-char *get_map_shm(struct sock_info *sock_info)
-{
- long page_size;
- int wait_shm_fd, ret;
- char *wait_shm_mmap;
-
- page_size = sysconf(_SC_PAGE_SIZE);
- if (page_size <= 0) {
- if (!page_size) {
- errno = EINVAL;
- }
- PERROR("Error in sysconf(_SC_PAGE_SIZE)");
- goto error;
- }
-
- lttng_ust_lock_fd_tracker();
- wait_shm_fd = get_wait_shm(sock_info, page_size);
- if (wait_shm_fd < 0) {
- lttng_ust_unlock_fd_tracker();
- goto error;
- }
-
- ret = lttng_ust_add_fd_to_tracker(wait_shm_fd);
- if (ret < 0) {
- ret = close(wait_shm_fd);
- if (!ret) {
- PERROR("Error closing fd");
- }
- lttng_ust_unlock_fd_tracker();
- goto error;
- }
-
- wait_shm_fd = ret;
- lttng_ust_unlock_fd_tracker();
-
- wait_shm_mmap = mmap(NULL, page_size, PROT_READ,
- MAP_SHARED, wait_shm_fd, 0);
-
- /* close shm fd immediately after taking the mmap reference */
- lttng_ust_lock_fd_tracker();
- ret = close(wait_shm_fd);
- if (!ret) {
- lttng_ust_delete_fd_from_tracker(wait_shm_fd);
- } else {
- PERROR("Error closing fd");
- }
- lttng_ust_unlock_fd_tracker();
-
- if (wait_shm_mmap == MAP_FAILED) {
- DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode.");
- goto error;
- }
- return wait_shm_mmap;
-
-error:
- return NULL;
-}
-
-static
-void wait_for_sessiond(struct sock_info *sock_info)
-{
- /* Use ust_lock to check if we should quit. */
- if (ust_lock()) {
- goto quit;
- }
- if (wait_poll_fallback) {
- goto error;
- }
- ust_unlock();
-
- assert(sock_info->wait_shm_mmap);
-
- DBG("Waiting for %s apps sessiond", sock_info->name);
- /* Wait for futex wakeup */
- if (uatomic_read((int32_t *) sock_info->wait_shm_mmap))
- goto end_wait;
-
- while (futex_async((int32_t *) sock_info->wait_shm_mmap,
- FUTEX_WAIT, 0, NULL, NULL, 0)) {
- switch (errno) {
- case EWOULDBLOCK:
- /* Value already changed. */
- goto end_wait;
- case EINTR:
- /* Retry if interrupted by signal. */
- break; /* Get out of switch. */
- case EFAULT:
- wait_poll_fallback = 1;
- DBG(
-"Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) "
-"do not support FUTEX_WAKE on read-only memory mappings correctly. "
-"Please upgrade your kernel "
-"(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
-"mainline). LTTng-UST will use polling mode fallback.");
- if (ust_debug())
- PERROR("futex");
- goto end_wait;
- }
- }
-end_wait:
- return;
-
-quit:
- ust_unlock();
- return;
-
-error:
- ust_unlock();
- return;
-}
-
-/*
- * This thread does not allocate any resource, except within
- * handle_message, within mutex protection. This mutex protects against
- * fork and exit.
- * The other moment it allocates resources is at socket connection, which
- * is also protected by the mutex.
- */
-static
-void *ust_listener_thread(void *arg)
-{
- struct sock_info *sock_info = arg;
- int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
- long timeout;
-
- lttng_ust_fixup_tls();
- /*
- * If available, add '-ust' to the end of this thread's
- * process name
- */
- ret = lttng_ust_setustprocname();
- if (ret) {
- ERR("Unable to set UST process name");
- }
-
- /* Restart trying to connect to the session daemon */
-restart:
- if (prev_connect_failed) {
- /* Wait for sessiond availability with pipe */
- wait_for_sessiond(sock_info);
- if (has_waited) {
- has_waited = 0;
- /*
- * Sleep for 5 seconds before retrying after a
- * sequence of failure / wait / failure. This
- * deals with a killed or broken session daemon.
- */
- sleep(5);
- } else {
- has_waited = 1;
- }
- prev_connect_failed = 0;
- }
-
- if (ust_lock()) {
- goto quit;
- }
-
- if (sock_info->socket != -1) {
- /* FD tracker is updated by ustcomm_close_unix_sock() */
- ret = ustcomm_close_unix_sock(sock_info->socket);
- if (ret) {
- ERR("Error closing %s ust cmd socket",
- sock_info->name);
- }
- sock_info->socket = -1;
- }
- if (sock_info->notify_socket != -1) {
- /* FD tracker is updated by ustcomm_close_unix_sock() */
- ret = ustcomm_close_unix_sock(sock_info->notify_socket);
- if (ret) {
- ERR("Error closing %s ust notify socket",
- sock_info->name);
- }
- sock_info->notify_socket = -1;
- }
-
-
- /*
- * Register. We need to perform both connect and sending
- * registration message before doing the next connect otherwise
- * we may reach unix socket connect queue max limits and block
- * on the 2nd connect while the session daemon is awaiting the
- * first connect registration message.
- */
- /* Connect cmd socket */
- lttng_ust_lock_fd_tracker();
- ret = ustcomm_connect_unix_sock(sock_info->sock_path,
- get_connect_sock_timeout());
- if (ret < 0) {
- lttng_ust_unlock_fd_tracker();
- DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
- prev_connect_failed = 1;
-
- /*
- * If we cannot find the sessiond daemon, don't delay
- * constructor execution.
- */
- ret = handle_register_failed(sock_info);
- assert(!ret);
- ust_unlock();
- goto restart;
- }
- fd = ret;
- ret = lttng_ust_add_fd_to_tracker(fd);
- if (ret < 0) {
- ret = close(fd);
- if (ret) {
- PERROR("close on sock_info->socket");
- }
- ret = -1;
- lttng_ust_unlock_fd_tracker();
- ust_unlock();
- goto quit;
- }
-
- sock_info->socket = ret;
- lttng_ust_unlock_fd_tracker();
-
- ust_unlock();
- /*
- * Unlock/relock ust lock because connect is blocking (with
- * timeout). Don't delay constructors on the ust lock for too
- * long.
- */
- if (ust_lock()) {
- goto quit;
- }
-
- /*
- * Create only one root handle per listener thread for the whole
- * process lifetime, so we ensure we get ID which is statically
- * assigned to the root handle.
- */
- if (sock_info->root_handle == -1) {
- ret = lttng_abi_create_root_handle();
- if (ret < 0) {
- ERR("Error creating root handle");
- goto quit;
- }
- sock_info->root_handle = ret;
- }
-
- ret = register_to_sessiond(sock_info->socket, USTCTL_SOCKET_CMD);
- if (ret < 0) {
- ERR("Error registering to %s ust cmd socket",
- sock_info->name);
- prev_connect_failed = 1;
- /*
- * If we cannot register to the sessiond daemon, don't
- * delay constructor execution.
- */
- ret = handle_register_failed(sock_info);
- assert(!ret);
- ust_unlock();
- goto restart;
- }
-
- ust_unlock();
- /*
- * Unlock/relock ust lock because connect is blocking (with
- * timeout). Don't delay constructors on the ust lock for too
- * long.
- */
- if (ust_lock()) {
- goto quit;
- }
-
- /* Connect notify socket */
- lttng_ust_lock_fd_tracker();
- ret = ustcomm_connect_unix_sock(sock_info->sock_path,
- get_connect_sock_timeout());
- if (ret < 0) {
- lttng_ust_unlock_fd_tracker();
- DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name);
- prev_connect_failed = 1;
-
- /*
- * If we cannot find the sessiond daemon, don't delay
- * constructor execution.
- */
- ret = handle_register_failed(sock_info);
- assert(!ret);
- ust_unlock();
- goto restart;
- }
-
- fd = ret;
- ret = lttng_ust_add_fd_to_tracker(fd);
- if (ret < 0) {
- ret = close(fd);
- if (ret) {
- PERROR("close on sock_info->notify_socket");
- }
- ret = -1;
- lttng_ust_unlock_fd_tracker();
- ust_unlock();
- goto quit;
- }
-
- sock_info->notify_socket = ret;
- lttng_ust_unlock_fd_tracker();
-
- ust_unlock();
- /*
- * Unlock/relock ust lock because connect is blocking (with
- * timeout). Don't delay constructors on the ust lock for too
- * long.
- */
- if (ust_lock()) {
- goto quit;
- }
-
- timeout = get_notify_sock_timeout();
- if (timeout >= 0) {
- /*
- * Give at least 10ms to sessiond to reply to
- * notifications.
- */
- if (timeout < 10)
- timeout = 10;
- ret = ustcomm_setsockopt_rcv_timeout(sock_info->notify_socket,
- timeout);
- if (ret < 0) {
- WARN("Error setting socket receive timeout");
- }
- ret = ustcomm_setsockopt_snd_timeout(sock_info->notify_socket,
- timeout);
- if (ret < 0) {
- WARN("Error setting socket send timeout");
- }
- } else if (timeout < -1) {
- WARN("Unsupported timeout value %ld", timeout);
- }
-
- ret = register_to_sessiond(sock_info->notify_socket,
- USTCTL_SOCKET_NOTIFY);
- if (ret < 0) {
- ERR("Error registering to %s ust notify socket",
- sock_info->name);
- prev_connect_failed = 1;
- /*
- * If we cannot register to the sessiond daemon, don't
- * delay constructor execution.
- */
- ret = handle_register_failed(sock_info);
- assert(!ret);
- ust_unlock();
- goto restart;
- }
- sock = sock_info->socket;
-
- ust_unlock();
-
- for (;;) {
- ssize_t len;
- struct ustcomm_ust_msg lum;
-
- len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum));
- switch (len) {
- case 0: /* orderly shutdown */
- DBG("%s lttng-sessiond has performed an orderly shutdown", sock_info->name);
- if (ust_lock()) {
- goto quit;
- }
- /*
- * Either sessiond has shutdown or refused us by closing the socket.
- * In either case, we don't want to delay construction execution,
- * and we need to wait before retry.
- */
- prev_connect_failed = 1;
- /*
- * If we cannot register to the sessiond daemon, don't
- * delay constructor execution.
- */
- ret = handle_register_failed(sock_info);
- assert(!ret);
- ust_unlock();
- goto end;
- case sizeof(lum):
- print_cmd(lum.cmd, lum.handle);
- ret = handle_message(sock_info, sock, &lum);
- if (ret) {
- ERR("Error handling message for %s socket",
- sock_info->name);
- /*
- * Close socket if protocol error is
- * detected.
- */
- goto end;
- }
- continue;
- default:
- if (len < 0) {
- DBG("Receive failed from lttng-sessiond with errno %d", (int) -len);
- } else {
- DBG("incorrect message size (%s socket): %zd", sock_info->name, len);
- }
- if (len == -ECONNRESET) {
- DBG("%s remote end closed connection", sock_info->name);
- goto end;
- }
- goto end;
- }
-
- }
-end:
- if (ust_lock()) {
- goto quit;
- }
- /* Cleanup socket handles before trying to reconnect */
- lttng_ust_objd_table_owner_cleanup(sock_info);
- ust_unlock();
- goto restart; /* try to reconnect */
-
-quit:
- ust_unlock();
-
- pthread_mutex_lock(&ust_exit_mutex);
- sock_info->thread_active = 0;
- pthread_mutex_unlock(&ust_exit_mutex);
- return NULL;
-}
-
-/*
- * Weak symbol to call when the ust malloc wrapper is not loaded.
- */
-__attribute__((weak))
-void lttng_ust_malloc_wrapper_init(void)
-{
-}
-
-/*
- * sessiond monitoring thread: monitor presence of global and per-user
- * sessiond by polling the application common named pipe.
- */
-void __attribute__((constructor)) lttng_ust_init(void)
-{
- struct timespec constructor_timeout;
- sigset_t sig_all_blocked, orig_parent_mask;
- pthread_attr_t thread_attr;
- int timeout_mode;
- int ret;
- void *handle;
-
- if (uatomic_xchg(&initialized, 1) == 1)
- return;
-
- /*
- * Fixup interdependency between TLS fixup mutex (which happens
- * to be the dynamic linker mutex) and ust_lock, taken within
- * the ust lock.
- */
- lttng_ust_fixup_tls();
-
- lttng_ust_loaded = 1;
-
- /*
- * We need to ensure that the liblttng-ust library is not unloaded to avoid
- * the unloading of code used by the ust_listener_threads as we can not
- * reliably know when they exited. To do that, manually load
- * liblttng-ust.so to increment the dynamic loader's internal refcount for
- * this library so it never becomes zero, thus never gets unloaded from the
- * address space of the process. Since we are already running in the
- * constructor of the LTTNG_UST_LIB_SO_NAME library, calling dlopen will
- * simply increment the refcount and no additionnal work is needed by the
- * dynamic loader as the shared library is already loaded in the address
- * space. As a safe guard, we use the RTLD_NODELETE flag to prevent
- * unloading of the UST library if its refcount becomes zero (which should
- * never happen). Do the return value check but discard the handle at the
- * end of the function as it's not needed.
- */
- handle = dlopen(LTTNG_UST_LIB_SO_NAME, RTLD_LAZY | RTLD_NODELETE);
- if (!handle) {
- ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SO_NAME);
- }
-
- /*
- * We want precise control over the order in which we construct
- * our sub-libraries vs starting to receive commands from
- * sessiond (otherwise leading to errors when trying to create
- * sessiond before the init functions are completed).
- */
- init_usterr();
- lttng_ust_getenv_init(); /* Needs init_usterr() to be completed. */
- init_tracepoint();
- lttng_ust_init_fd_tracker();
- lttng_ust_clock_init();
- lttng_ust_getcpu_init();
- lttng_ust_statedump_init();
- lttng_ring_buffer_metadata_client_init();
- lttng_ring_buffer_client_overwrite_init();
- lttng_ring_buffer_client_overwrite_rt_init();
- lttng_ring_buffer_client_discard_init();
- lttng_ring_buffer_client_discard_rt_init();
- lttng_perf_counter_init();
- /*
- * Invoke ust malloc wrapper init before starting other threads.
- */
- lttng_ust_malloc_wrapper_init();
-
- timeout_mode = get_constructor_timeout(&constructor_timeout);
-
- get_allow_blocking();
-
- ret = sem_init(&constructor_wait, 0, 0);
- if (ret) {
- PERROR("sem_init");
- }
-
- ret = setup_global_apps();
- if (ret) {
- assert(global_apps.allowed == 0);
- DBG("global apps setup returned %d", ret);
- }
-
- ret = setup_local_apps();
- if (ret) {
- assert(local_apps.allowed == 0);
- DBG("local apps setup returned %d", ret);
- }
-
- /* A new thread created by pthread_create inherits the signal mask
- * from the parent. To avoid any signal being received by the
- * listener thread, we block all signals temporarily in the parent,
- * while we create the listener thread.
- */
- sigfillset(&sig_all_blocked);
- ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
-
- ret = pthread_attr_init(&thread_attr);
- if (ret) {
- ERR("pthread_attr_init: %s", strerror(ret));
- }
- ret = pthread_attr_setdetachstate(&thread_attr, PTHREAD_CREATE_DETACHED);
- if (ret) {
- ERR("pthread_attr_setdetachstate: %s", strerror(ret));
- }
-
- if (global_apps.allowed) {
- pthread_mutex_lock(&ust_exit_mutex);
- ret = pthread_create(&global_apps.ust_listener, &thread_attr,
- ust_listener_thread, &global_apps);
- if (ret) {
- ERR("pthread_create global: %s", strerror(ret));
- }
- global_apps.thread_active = 1;
- pthread_mutex_unlock(&ust_exit_mutex);
- } else {
- handle_register_done(&global_apps);
- }
-
- if (local_apps.allowed) {
- pthread_mutex_lock(&ust_exit_mutex);
- ret = pthread_create(&local_apps.ust_listener, &thread_attr,
- ust_listener_thread, &local_apps);
- if (ret) {
- ERR("pthread_create local: %s", strerror(ret));
- }
- local_apps.thread_active = 1;
- pthread_mutex_unlock(&ust_exit_mutex);
- } else {
- handle_register_done(&local_apps);
- }
- ret = pthread_attr_destroy(&thread_attr);
- if (ret) {
- ERR("pthread_attr_destroy: %s", strerror(ret));
- }
-
- /* Restore original signal mask in parent */
- ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
- if (ret) {
- ERR("pthread_sigmask: %s", strerror(ret));
- }
-
- switch (timeout_mode) {
- case 1: /* timeout wait */
- do {
- ret = sem_timedwait(&constructor_wait,
- &constructor_timeout);
- } while (ret < 0 && errno == EINTR);
- if (ret < 0) {
- switch (errno) {
- case ETIMEDOUT:
- ERR("Timed out waiting for lttng-sessiond");
- break;
- case EINVAL:
- PERROR("sem_timedwait");
- break;
- default:
- ERR("Unexpected error \"%s\" returned by sem_timedwait",
- strerror(errno));
- }
- }
- break;
- case -1:/* wait forever */
- do {
- ret = sem_wait(&constructor_wait);
- } while (ret < 0 && errno == EINTR);
- if (ret < 0) {
- switch (errno) {
- case EINVAL:
- PERROR("sem_wait");
- break;
- default:
- ERR("Unexpected error \"%s\" returned by sem_wait",
- strerror(errno));
- }
- }
- break;
- case 0: /* no timeout */
- break;
- }
-}
-
-static
-void lttng_ust_cleanup(int exiting)
-{
- cleanup_sock_info(&global_apps, exiting);
- cleanup_sock_info(&local_apps, exiting);
- local_apps.allowed = 0;
- global_apps.allowed = 0;
- /*
- * The teardown in this function all affect data structures
- * accessed under the UST lock by the listener thread. This
- * lock, along with the lttng_ust_comm_should_quit flag, ensure
- * that none of these threads are accessing this data at this
- * point.
- */
- lttng_ust_abi_exit();
- lttng_ust_events_exit();
- lttng_perf_counter_exit();
- lttng_ring_buffer_client_discard_rt_exit();
- lttng_ring_buffer_client_discard_exit();
- lttng_ring_buffer_client_overwrite_rt_exit();
- lttng_ring_buffer_client_overwrite_exit();
- lttng_ring_buffer_metadata_client_exit();
- lttng_ust_statedump_destroy();
- exit_tracepoint();
- if (!exiting) {
- /* Reinitialize values for fork */
- sem_count = sem_count_initial_value;
- lttng_ust_comm_should_quit = 0;
- initialized = 0;
- }
-}
-
-void __attribute__((destructor)) lttng_ust_exit(void)
-{
- int ret;
-
- /*
- * Using pthread_cancel here because:
- * A) we don't want to hang application teardown.
- * B) the thread is not allocating any resource.
- */
-
- /*
- * Require the communication thread to quit. Synchronize with
- * mutexes to ensure it is not in a mutex critical section when
- * pthread_cancel is later called.
- */
- ust_lock_nocheck();
- lttng_ust_comm_should_quit = 1;
- ust_unlock();
-
- pthread_mutex_lock(&ust_exit_mutex);
- /* cancel threads */
- if (global_apps.thread_active) {
- ret = pthread_cancel(global_apps.ust_listener);
- if (ret) {
- ERR("Error cancelling global ust listener thread: %s",
- strerror(ret));
- } else {
- global_apps.thread_active = 0;
- }
- }
- if (local_apps.thread_active) {
- ret = pthread_cancel(local_apps.ust_listener);
- if (ret) {
- ERR("Error cancelling local ust listener thread: %s",
- strerror(ret));
- } else {
- local_apps.thread_active = 0;
- }
- }
- pthread_mutex_unlock(&ust_exit_mutex);
-
- /*
- * Do NOT join threads: use of sys_futex makes it impossible to
- * join the threads without using async-cancel, but async-cancel
- * is delivered by a signal, which could hit the target thread
- * anywhere in its code path, including while the ust_lock() is
- * held, causing a deadlock for the other thread. Let the OS
- * cleanup the threads if there are stalled in a syscall.
- */
- lttng_ust_cleanup(1);
-}
-
-/*
- * We exclude the worker threads across fork and clone (except
- * CLONE_VM), because these system calls only keep the forking thread
- * running in the child. Therefore, we don't want to call fork or clone
- * in the middle of an tracepoint or ust tracing state modification.
- * Holding this mutex protects these structures across fork and clone.
- */
-void ust_before_fork(sigset_t *save_sigset)
-{
- /*
- * Disable signals. This is to avoid that the child intervenes
- * before it is properly setup for tracing. It is safer to
- * disable all signals, because then we know we are not breaking
- * anything by restoring the original mask.
- */
- sigset_t all_sigs;
- int ret;
-
- /* Fixup lttng-ust TLS. */
- lttng_ust_fixup_tls();
-
- if (URCU_TLS(lttng_ust_nest_count))
- return;
- /* Disable signals */
- sigfillset(&all_sigs);
- ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset);
- if (ret == -1) {
- PERROR("sigprocmask");
- }
-
- pthread_mutex_lock(&ust_fork_mutex);
-
- ust_lock_nocheck();
- urcu_bp_before_fork();
- lttng_ust_lock_fd_tracker();
- lttng_perf_lock();
-}
-
-static void ust_after_fork_common(sigset_t *restore_sigset)
-{
- int ret;
-
- DBG("process %d", getpid());
- lttng_perf_unlock();
- lttng_ust_unlock_fd_tracker();
- ust_unlock();
-
- pthread_mutex_unlock(&ust_fork_mutex);
-
- /* Restore signals */
- ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL);
- if (ret == -1) {
- PERROR("sigprocmask");
- }
-}
-
-void ust_after_fork_parent(sigset_t *restore_sigset)
-{
- if (URCU_TLS(lttng_ust_nest_count))
- return;
- DBG("process %d", getpid());
- urcu_bp_after_fork_parent();
- /* Release mutexes and reenable signals */
- ust_after_fork_common(restore_sigset);
-}
-
-/*
- * After fork, in the child, we need to cleanup all the leftover state,
- * except the worker thread which already magically disappeared thanks
- * to the weird Linux fork semantics. After tyding up, we call
- * lttng_ust_init() again to start over as a new PID.
- *
- * This is meant for forks() that have tracing in the child between the
- * fork and following exec call (if there is any).
- */
-void ust_after_fork_child(sigset_t *restore_sigset)
-{
- if (URCU_TLS(lttng_ust_nest_count))
- return;
- lttng_context_vpid_reset();
- lttng_context_vtid_reset();
- lttng_context_procname_reset();
- DBG("process %d", getpid());
- /* Release urcu mutexes */
- urcu_bp_after_fork_child();
- lttng_ust_cleanup(0);
- /* Release mutexes and reenable signals */
- ust_after_fork_common(restore_sigset);
- lttng_ust_init();
-}
-
-void lttng_ust_sockinfo_session_enabled(void *owner)
-{
- struct sock_info *sock_info = owner;
- sock_info->statedump_pending = 1;
-}
projects / lttng-ust.git / blobdiff