X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=libust%2Flttng-ust-comm.c;fp=libust%2Flttng-ust-comm.c;h=0000000000000000000000000000000000000000;hb=69400ac4a4e6575f749c6326df7c2a2c8ac3bdc5;hp=1246c654c34f5d83f65dc2425a9f0a4728179292;hpb=f3049ad9e7b72287888452b9ed542c0f36e6eefe;p=ust.git diff --git a/libust/lttng-ust-comm.c b/libust/lttng-ust-comm.c deleted file mode 100644 index 1246c65..0000000 --- a/libust/lttng-ust-comm.c +++ /dev/null @@ -1,935 +0,0 @@ -/* - * lttng-ust-comm.c - * - * Copyright (C) 2011 David Goulet - * Copyright (C) 2011 Mathieu Desnoyers - * - * 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 -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include -#include -#include -#include -#include -#include -#include "ltt-tracer-core.h" - -/* - * 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. - */ - -/* Should the ust comm thread quit ? */ -static int lttng_ust_comm_should_quit; - -/* - * 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. - */ -static int sem_count = { 2 }; - -/* - * Info about socket and associated listener thread. - */ -struct sock_info { - const char *name; - pthread_t ust_listener; /* listener thread */ - int root_handle; - int constructor_sem_posted; - int allowed; - int global; - - char sock_path[PATH_MAX]; - int socket; - - char wait_shm_path[PATH_MAX]; - char *wait_shm_mmap; -}; - -/* Socket from app (connect) to session daemon (listen) for communication */ -struct sock_info global_apps = { - .name = "global", - .global = 1, - - .root_handle = -1, - .allowed = 1, - - .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, - .socket = -1, - - .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, -}; - -/* TODO: allow global_apps_sock_path override */ - -struct sock_info local_apps = { - .name = "local", - .global = 0, - .root_handle = -1, - .allowed = 0, /* Check setuid bit first */ - - .socket = -1, -}; - -static int wait_poll_fallback; - -extern void ltt_ring_buffer_client_overwrite_init(void); -extern void ltt_ring_buffer_client_discard_init(void); -extern void ltt_ring_buffer_metadata_client_init(void); -extern void ltt_ring_buffer_client_overwrite_exit(void); -extern void ltt_ring_buffer_client_discard_exit(void); -extern void ltt_ring_buffer_metadata_client_exit(void); - -static -int setup_local_apps(void) -{ - const char *home_dir; - uid_t uid; - - uid = getuid(); - /* - * Disallow per-user tracing for setuid binaries. - */ - if (uid != geteuid()) { - local_apps.allowed = 0; - return 0; - } else { - local_apps.allowed = 1; - } - home_dir = (const char *) getenv("HOME"); - if (!home_dir) - return -ENOENT; - snprintf(local_apps.sock_path, PATH_MAX, - DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); - snprintf(local_apps.wait_shm_path, PATH_MAX, - DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); - return 0; -} - -static -int register_app_to_sessiond(int socket) -{ - ssize_t ret; - int prctl_ret; - struct { - uint32_t major; - uint32_t minor; - pid_t pid; - pid_t ppid; - uid_t uid; - gid_t gid; - char name[16]; /* process name */ - } reg_msg; - - reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; - reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; - reg_msg.pid = getpid(); - reg_msg.ppid = getppid(); - reg_msg.uid = getuid(); - reg_msg.gid = getgid(); - prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0); - if (prctl_ret) { - ERR("Error executing prctl"); - return -errno; - } - - ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); - if (ret >= 0 && ret != sizeof(reg_msg)) - return -EIO; - return ret; -} - -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; - case -1: - if (errno == ECONNRESET) { - printf("remote end closed connection\n"); - return 0; - } - return -1; - default: - printf("incorrect message size: %zd\n", len); - return -1; - } -} - -static -int handle_register_done(struct sock_info *sock_info) -{ - int ret; - - if (sock_info->constructor_sem_posted) - return 0; - sock_info->constructor_sem_posted = 1; - if (uatomic_read(&sem_count) <= 0) { - return 0; - } - ret = uatomic_add_return(&sem_count, -1); - if (ret == 0) { - ret = sem_post(&constructor_wait); - assert(!ret); - } - return 0; -} - -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; - int shm_fd, wait_fd; - - ust_lock(); - - memset(&lur, 0, sizeof(lur)); - - if (lttng_ust_comm_should_quit) { - ret = -EPERM; - goto end; - } - - ops = objd_ops(lum->handle); - if (!ops) { - ret = -ENOENT; - goto end; - } - - 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); - break; - default: - if (ops->cmd) - ret = ops->cmd(lum->handle, lum->cmd, - (unsigned long) &lum->u); - else - ret = -ENOSYS; - break; - } - -end: - lur.handle = lum->handle; - lur.cmd = lum->cmd; - lur.ret_val = ret; - if (ret >= 0) { - lur.ret_code = USTCOMM_OK; - } else { - //lur.ret_code = USTCOMM_SESSION_FAIL; - lur.ret_code = ret; - } - switch (lum->cmd) { - case LTTNG_UST_STREAM: - /* - * Special-case reply to send stream info. - * Use lum.u output. - */ - lur.u.stream.memory_map_size = lum->u.stream.memory_map_size; - shm_fd = lum->u.stream.shm_fd; - wait_fd = lum->u.stream.wait_fd; - break; - case LTTNG_UST_METADATA: - case LTTNG_UST_CHANNEL: - lur.u.channel.memory_map_size = lum->u.channel.memory_map_size; - shm_fd = lum->u.channel.shm_fd; - wait_fd = lum->u.channel.wait_fd; - break; - case LTTNG_UST_VERSION: - lur.u.version = lum->u.version; - break; - } - ret = send_reply(sock, &lur); - if (ret < 0) { - perror("error sending reply"); - goto error; - } - - if ((lum->cmd == LTTNG_UST_STREAM - || lum->cmd == LTTNG_UST_CHANNEL - || lum->cmd == LTTNG_UST_METADATA) - && lur.ret_code == USTCOMM_OK) { - /* we also need to send the file descriptors. */ - ret = ustcomm_send_fds_unix_sock(sock, - &shm_fd, &shm_fd, - 1, sizeof(int)); - if (ret < 0) { - perror("send shm_fd"); - goto error; - } - ret = ustcomm_send_fds_unix_sock(sock, - &wait_fd, &wait_fd, - 1, sizeof(int)); - if (ret < 0) { - perror("send wait_fd"); - goto error; - } - } -error: - ust_unlock(); - return ret; -} - -static -void cleanup_sock_info(struct sock_info *sock_info) -{ - int ret; - - if (sock_info->socket != -1) { - ret = close(sock_info->socket); - if (ret) { - ERR("Error closing apps socket"); - } - sock_info->socket = -1; - } - if (sock_info->root_handle != -1) { - ret = lttng_ust_objd_unref(sock_info->root_handle); - if (ret) { - ERR("Error unref root handle"); - } - sock_info->root_handle = -1; - } - sock_info->constructor_sem_posted = 0; - if (sock_info->wait_shm_mmap) { - ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_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) { - 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; - } - /* - * If the open failed because the file did not exist, try - * creating it ourself. - */ - pid = fork(); - 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 (!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) -{ - size_t mmap_size = sysconf(_SC_PAGE_SIZE); - int wait_shm_fd, ret; - char *wait_shm_mmap; - - wait_shm_fd = get_wait_shm(sock_info, mmap_size); - if (wait_shm_fd < 0) { - goto error; - } - wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, - MAP_SHARED, wait_shm_fd, 0); - /* close shm fd immediately after taking the mmap reference */ - ret = close(wait_shm_fd); - if (ret) { - PERROR("Error closing fd"); - } - 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) -{ - int ret; - - ust_lock(); - if (lttng_ust_comm_should_quit) { - goto quit; - } - if (wait_poll_fallback) { - goto error; - } - if (!sock_info->wait_shm_mmap) { - sock_info->wait_shm_mmap = get_map_shm(sock_info); - if (!sock_info->wait_shm_mmap) - goto error; - } - ust_unlock(); - - DBG("Waiting for %s apps sessiond", sock_info->name); - /* Wait for futex wakeup */ - if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { - ret = futex_async((int32_t *) sock_info->wait_shm_mmap, - FUTEX_WAIT, 0, NULL, NULL, 0); - if (ret < 0) { - if (errno == EFAULT) { - wait_poll_fallback = 1; - WARN( -"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."); - } - PERROR("futex"); - } - } - 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 connexion, 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; - - /* 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); - } - has_waited = 1; - prev_connect_failed = 0; - } - ust_lock(); - - if (lttng_ust_comm_should_quit) { - ust_unlock(); - goto quit; - } - - if (sock_info->socket != -1) { - ret = close(sock_info->socket); - if (ret) { - ERR("Error closing %s apps socket", sock_info->name); - } - sock_info->socket = -1; - } - - /* Register */ - ret = ustcomm_connect_unix_sock(sock_info->sock_path); - if (ret < 0) { - ERR("Error connecting 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_done(sock_info); - assert(!ret); - ust_unlock(); - goto restart; - } - - sock_info->socket = sock = ret; - - /* - * Create only one root handle per listener thread for the whole - * process lifetime. - */ - if (sock_info->root_handle == -1) { - ret = lttng_abi_create_root_handle(); - if (ret < 0) { - ERR("Error creating root handle"); - ust_unlock(); - goto quit; - } - sock_info->root_handle = ret; - } - - ret = register_app_to_sessiond(sock); - if (ret < 0) { - ERR("Error registering to %s apps socket", sock_info->name); - prev_connect_failed = 1; - /* - * If we cannot register to the sessiond daemon, don't - * delay constructor execution. - */ - ret = handle_register_done(sock_info); - assert(!ret); - ust_unlock(); - goto restart; - } - 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 ltt-sessiond has performed an orderly shutdown\n", sock_info->name); - goto end; - case sizeof(lum): - DBG("message received\n"); - ret = handle_message(sock_info, sock, &lum); - if (ret < 0) { - ERR("Error handling message for %s socket", sock_info->name); - } - continue; - case -1: - if (errno == ECONNRESET) { - ERR("%s remote end closed connection\n", sock_info->name); - goto end; - } - goto end; - default: - ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); - continue; - } - - } -end: - goto restart; /* try to reconnect */ -quit: - return NULL; -} - -/* - * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. - */ -static -int get_timeout(struct timespec *constructor_timeout) -{ - long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; - char *str_delay; - int ret; - - str_delay = getenv("UST_REGISTER_TIMEOUT"); - if (str_delay) { - constructor_delay_ms = strtol(str_delay, NULL, 10); - } - - 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) { - return -1; - } - 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; - } - return 1; -} - -/* - * sessiond monitoring thread: monitor presence of global and per-user - * sessiond by polling the application common named pipe. - */ -/* TODO */ - -void __attribute__((constructor)) lttng_ust_init(void) -{ - struct timespec constructor_timeout; - int timeout_mode; - int ret; - - if (uatomic_xchg(&initialized, 1) == 1) - return; - - /* - * 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(); - init_tracepoint(); - ltt_ring_buffer_metadata_client_init(); - ltt_ring_buffer_client_overwrite_init(); - ltt_ring_buffer_client_discard_init(); - - timeout_mode = get_timeout(&constructor_timeout); - - ret = sem_init(&constructor_wait, 0, 0); - assert(!ret); - - ret = setup_local_apps(); - if (ret) { - ERR("Error setting up to local apps"); - } - ret = pthread_create(&local_apps.ust_listener, NULL, - ust_listener_thread, &local_apps); - - if (local_apps.allowed) { - ret = pthread_create(&global_apps.ust_listener, NULL, - ust_listener_thread, &global_apps); - } else { - handle_register_done(&local_apps); - } - - switch (timeout_mode) { - case 1: /* timeout wait */ - do { - ret = sem_timedwait(&constructor_wait, - &constructor_timeout); - } while (ret < 0 && errno == EINTR); - if (ret < 0 && errno == ETIMEDOUT) { - ERR("Timed out waiting for ltt-sessiond"); - } else { - assert(!ret); - } - break; - case -1:/* wait forever */ - do { - ret = sem_wait(&constructor_wait); - } while (ret < 0 && errno == EINTR); - assert(!ret); - break; - case 0: /* no timeout */ - break; - } -} - -static -void lttng_ust_cleanup(int exiting) -{ - cleanup_sock_info(&global_apps); - if (local_apps.allowed) { - cleanup_sock_info(&local_apps); - } - lttng_ust_abi_exit(); - lttng_ust_events_exit(); - ltt_ring_buffer_client_discard_exit(); - ltt_ring_buffer_client_overwrite_exit(); - ltt_ring_buffer_metadata_client_exit(); - exit_tracepoint(); - if (!exiting) { - /* Reinitialize values for fork */ - sem_count = 2; - 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(); - lttng_ust_comm_should_quit = 1; - ust_unlock(); - - ret = pthread_cancel(global_apps.ust_listener); - if (ret) { - ERR("Error cancelling global ust listener thread"); - } - if (local_apps.allowed) { - ret = pthread_cancel(local_apps.ust_listener); - if (ret) { - ERR("Error cancelling local ust listener thread"); - } - } - 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(ust_fork_info_t *fork_info) -{ - /* - * 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; - - /* Disable signals */ - sigfillset(&all_sigs); - ret = sigprocmask(SIG_BLOCK, &all_sigs, &fork_info->orig_sigs); - if (ret == -1) { - PERROR("sigprocmask"); - } - ust_lock(); - rcu_bp_before_fork(); -} - -static void ust_after_fork_common(ust_fork_info_t *fork_info) -{ - int ret; - - DBG("process %d", getpid()); - ust_unlock(); - /* Restore signals */ - ret = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL); - if (ret == -1) { - PERROR("sigprocmask"); - } -} - -void ust_after_fork_parent(ust_fork_info_t *fork_info) -{ - DBG("process %d", getpid()); - rcu_bp_after_fork_parent(); - /* Release mutexes and reenable signals */ - ust_after_fork_common(fork_info); -} - -/* - * 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(ust_fork_info_t *fork_info) -{ - DBG("process %d", getpid()); - /* Release urcu mutexes */ - rcu_bp_after_fork_child(); - lttng_ust_cleanup(0); - lttng_context_vtid_reset(); - /* Release mutexes and reenable signals */ - ust_after_fork_common(fork_info); - lttng_ust_init(); -}