X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=libust%2Ftracectl.c;h=33c7280743973aa281993280596a8708d428561a;hb=8d6300d3b3cb0219e1109e931a2219dbd812b24d;hp=f720244530c9f60b77f5978875f712a5ea69658a;hpb=1d471d9fd21c9ef20cd7b0ea54a71168f0ad1b6e;p=ust.git diff --git a/libust/tracectl.c b/libust/tracectl.c index f720244..33c7280 100644 --- a/libust/tracectl.c +++ b/libust/tracectl.c @@ -63,12 +63,20 @@ static char receive_buffer[USTCOMM_BUFFER_SIZE]; static char send_buffer[USTCOMM_BUFFER_SIZE]; static int epoll_fd; + +/* + * Listener thread data vs fork() protection mechanism. Ensures that no listener + * thread mutexes and data structures are being concurrently modified or held by + * other threads when fork() is executed. + */ +static pthread_mutex_t listener_thread_data_mutex = PTHREAD_MUTEX_INITIALIZER; + +/* Mutex protecting listen_sock. Nests inside listener_thread_data_mutex. */ +static pthread_mutex_t listen_sock_mutex = PTHREAD_MUTEX_INITIALIZER; static struct ustcomm_sock *listen_sock; extern struct chan_info_struct chan_infos[]; -static struct cds_list_head open_buffers_list = CDS_LIST_HEAD_INIT(open_buffers_list); - static struct cds_list_head ust_socks = CDS_LIST_HEAD_INIT(ust_socks); /* volatile because shared between the listener and the main thread */ @@ -479,11 +487,6 @@ static int notify_buffer_mapped(const char *trace_name, CMM_STORE_SHARED(buffers_to_export, CMM_LOAD_SHARED(buffers_to_export)-1); } - /* The buffer has been exported, ergo, we can add it to the - * list of open buffers - */ - cds_list_add(&buf->open_buffers_list, &open_buffers_list); - unlock_traces: ltt_unlock_traces(); @@ -533,52 +536,47 @@ unlock_traces: return retval; } -static void listener_cleanup(void *ptr) +static void release_listener_mutex(void *ptr) { - ustcomm_del_named_sock(listen_sock, 0); + pthread_mutex_unlock(&listener_thread_data_mutex); } -static void force_subbuf_switch() +static void listener_cleanup(void *ptr) { - struct ust_buffer *buf; - - cds_list_for_each_entry(buf, &open_buffers_list, - open_buffers_list) { - ltt_force_switch(buf, FORCE_FLUSH); + pthread_mutex_lock(&listen_sock_mutex); + if (listen_sock) { + ustcomm_del_named_sock(listen_sock, 0); + listen_sock = NULL; } + pthread_mutex_unlock(&listen_sock_mutex); } -/* Simple commands are those which need only respond with a return value. */ -static int process_simple_client_cmd(int command, char *recv_buf) +static int force_subbuf_switch(const char *trace_name) { - int result; + struct ust_trace *trace; + int i, j, retval = 0; - switch(command) { - case SET_SOCK_PATH: - { - struct ustcomm_single_field *sock_msg; - sock_msg = (struct ustcomm_single_field *)recv_buf; - result = ustcomm_unpack_single_field(sock_msg); - if (result < 0) { - return result; + ltt_lock_traces(); + trace = _ltt_trace_find(trace_name); + if (!trace) { + retval = -ENODATA; + DBG("Cannot find trace. It was likely destroyed by the user."); + goto unlock_traces; + } + + for (i = 0; i < trace->nr_channels; i++) { + for (j = 0; j < trace->channels[i].n_cpus; j++) { + ltt_force_switch(trace->channels[i].buf[j], + FORCE_FLUSH); } - return setenv("UST_DAEMON_SOCKET", sock_msg->field, 1); } - case FORCE_SUBBUF_SWITCH: - /* FIXME: return codes? */ - force_subbuf_switch(); - - break; - - default: - return -EINVAL; - } +unlock_traces: + ltt_unlock_traces(); - return 0; + return retval; } - static int process_trace_cmd(int command, char *trace_name) { int result; @@ -696,6 +694,15 @@ static int process_trace_cmd(int command, char *trace_name) return result; } return 0; + case FORCE_SUBBUF_SWITCH: + DBG("force switch"); + + result = force_subbuf_switch(trace_name); + if (result < 0) { + ERR("force_subbuf_switch failed"); + return result; + } + return 0; } return 0; @@ -937,7 +944,7 @@ static void process_client_cmd(struct ustcomm_header *recv_header, print_markers(fp); fclose(fp); - reply_header->size = size; + reply_header->size = size + 1; /* Include final \0 */ result = ustcomm_send(sock, reply_header, ptr); @@ -963,7 +970,7 @@ static void process_client_cmd(struct ustcomm_header *recv_header, print_trace_events(fp); fclose(fp); - reply_header->size = size; + reply_header->size = size + 1; /* Include final \0 */ result = ustcomm_send(sock, reply_header, ptr); @@ -1021,6 +1028,21 @@ static void process_client_cmd(struct ustcomm_header *recv_header, goto send_response; } + case SET_SOCK_PATH: + { + struct ustcomm_single_field *sock_msg; + sock_msg = (struct ustcomm_single_field *)recv_buf; + result = ustcomm_unpack_single_field(sock_msg); + if (result < 0) { + reply_header->result = -EINVAL; + goto send_response; + } + + reply_header->result = setenv("UST_DAEMON_SOCKET", + sock_msg->field, 1); + + goto send_response; + } case START: case SETUP_TRACE: case ALLOC_TRACE: @@ -1028,6 +1050,7 @@ static void process_client_cmd(struct ustcomm_header *recv_header, case START_TRACE: case STOP_TRACE: case DESTROY_TRACE: + case FORCE_SUBBUF_SWITCH: { struct ustcomm_single_field *trace_inf = (struct ustcomm_single_field *)recv_buf; @@ -1046,11 +1069,9 @@ static void process_client_cmd(struct ustcomm_header *recv_header, } default: - reply_header->result = - process_simple_client_cmd(recv_header->command, - recv_buf); - goto send_response; + reply_header->result = -EINVAL; + goto send_response; } return; @@ -1080,6 +1101,8 @@ void *listener_main(void *p) } for (i = 0; i < nfds; i++) { + pthread_mutex_lock(&listener_thread_data_mutex); + pthread_cleanup_push(release_listener_mutex, NULL); epoll_sock = (struct ustcomm_sock *)events[i].data.ptr; if (epoll_sock == listen_sock) { addr_size = sizeof(struct sockaddr); @@ -1108,6 +1131,7 @@ void *listener_main(void *p) epoll_sock->fd); } } + pthread_cleanup_pop(1); /* release listener mutex */ } } @@ -1567,7 +1591,6 @@ void ust_potential_exec(void) static void ust_fork(void) { - struct ust_buffer *buf, *buf_tmp; struct ustcomm_sock *sock, *sock_tmp; struct ust_trace *trace, *trace_tmp; int result; @@ -1578,9 +1601,6 @@ static void ust_fork(void) /* Get the pid of the new process */ processpid = getpid(); - /* break lock if necessary */ - ltt_unlock_traces(); - /* * FIXME: This could be prettier, we loop over the list twice and * following good locking practice should lock around the loop @@ -1594,12 +1614,6 @@ static void ust_fork(void) ustcomm_del_sock(sock, 1); } - /* Delete all blocked consumers */ - cds_list_for_each_entry_safe(buf, buf_tmp, &open_buffers_list, - open_buffers_list) { - cds_list_del(&buf->open_buffers_list); - } - /* * FIXME: This could be prettier, we loop over the list twice and * following good locking practice should lock around the loop @@ -1608,8 +1622,11 @@ static void ust_fork(void) ltt_trace_destroy(trace->trace_name, 1); } - /* Clean up the listener socket and epoll, keeping the scoket file */ - ustcomm_del_named_sock(listen_sock, 1); + /* Clean up the listener socket and epoll, keeping the socket file */ + if (listen_sock) { + ustcomm_del_named_sock(listen_sock, 1); + listen_sock = NULL; + } close(epoll_fd); /* Re-start the launch sequence */ @@ -1664,6 +1681,17 @@ void ust_before_fork(ust_fork_info_t *fork_info) PERROR("sigprocmask"); return; } + + /* + * Take the fork lock to make sure we are not in the middle of + * something in the listener thread. + */ + pthread_mutex_lock(&listener_thread_data_mutex); + /* + * Hold listen_sock_mutex to protect from listen_sock teardown. + */ + pthread_mutex_lock(&listen_sock_mutex); + rcu_bp_before_fork(); } /* Don't call this function directly in a traced program */ @@ -1671,6 +1699,9 @@ static void ust_after_fork_common(ust_fork_info_t *fork_info) { int result; + pthread_mutex_unlock(&listen_sock_mutex); + pthread_mutex_unlock(&listener_thread_data_mutex); + /* Restore signals */ result = sigprocmask(SIG_SETMASK, &fork_info->orig_sigs, NULL); if (result == -1) { @@ -1681,16 +1712,20 @@ static void ust_after_fork_common(ust_fork_info_t *fork_info) void ust_after_fork_parent(ust_fork_info_t *fork_info) { - /* Reenable signals */ + rcu_bp_after_fork_parent(); + /* Release mutexes and reenable signals */ ust_after_fork_common(fork_info); } void ust_after_fork_child(ust_fork_info_t *fork_info) { - /* First sanitize the child */ + /* Release urcu mutexes */ + rcu_bp_after_fork_child(); + + /* Sanitize the child */ ust_fork(); - /* Then reenable interrupts */ + /* Then release mutexes and reenable signals */ ust_after_fork_common(fork_info); }