X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=src%2Flib%2Flttng-ust%2Flttng-ust-comm.c;h=0fe2da466ad1cce241b0b82efd864e651223341e;hb=8e95eaadb72a1a97486f15cc128ff6ed2fcd0196;hp=61f0b34adc9d634113119ddf323a8b056aff8bde;hpb=08ba2503b86d1506117c077c99eb1c38973a48f3;p=lttng-ust.git diff --git a/src/lib/lttng-ust/lttng-ust-comm.c b/src/lib/lttng-ust/lttng-ust-comm.c index 61f0b34a..0fe2da46 100644 --- a/src/lib/lttng-ust/lttng-ust-comm.c +++ b/src/lib/lttng-ust/lttng-ust-comm.c @@ -1,7 +1,7 @@ /* * SPDX-License-Identifier: LGPL-2.1-only * - * Copyright (C) 2011 David Goulet + * Copyright (C) 2011 EfficiOS Inc. * Copyright (C) 2011 Mathieu Desnoyers */ @@ -38,6 +38,7 @@ #include #include #include +#include #include #include "lib/lttng-ust/futex.h" #include "common/ustcomm.h" @@ -50,14 +51,13 @@ #include "common/procname.h" #include "common/ringbuffer/rb-init.h" #include "lttng-ust-statedump.h" -#include "clock.h" -#include "lib/lttng-ust/getcpu.h" +#include "common/clock.h" #include "common/getenv.h" #include "lib/lttng-ust/events.h" #include "context-internal.h" #include "common/align.h" -#include "lttng-counter-client.h" -#include "lttng-rb-clients.h" +#include "common/counter-clients/clients.h" +#include "common/ringbuffer-clients/clients.h" /* * Has lttng ust comm constructor been called ? @@ -118,6 +118,28 @@ static int lttng_ust_comm_should_quit; */ int lttng_ust_loaded __attribute__((weak)); +/* + * Notes on async-signal-safety of ust lock: a few libc functions are used + * which are not strictly async-signal-safe: + * + * - pthread_setcancelstate + * - pthread_mutex_lock + * - pthread_mutex_unlock + * + * As of glibc 2.35, the implementation of pthread_setcancelstate only + * touches TLS data, and it appears to be safe to use from signal + * handlers. If the libc implementation changes, this will need to be + * revisited, and we may ask glibc to provide an async-signal-safe + * pthread_setcancelstate. + * + * As of glibc 2.35, the implementation of pthread_mutex_lock/unlock + * for fast mutexes only relies on the pthread_mutex_t structure. + * Disabling signals around all uses of this mutex ensures + * signal-safety. If the libc implementation changes and eventually uses + * other global resources, this will need to be revisited and we may + * need to implement our own mutex. + */ + /* * Return 0 on success, -1 if should quit. * The lock is taken in both cases. @@ -126,25 +148,21 @@ int lttng_ust_loaded __attribute__((weak)); int ust_lock(void) { sigset_t sig_all_blocked, orig_mask; - int ret, oldstate; + int ret; - 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"); + if (lttng_ust_cancelstate_disable_push()) { + ERR("lttng_ust_cancelstate_disable_push"); } sigfillset(&sig_all_blocked); ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask); if (ret) { - ERR("pthread_sigmask: %s", strerror(ret)); + ERR("pthread_sigmask: ret=%d", 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)); + ERR("pthread_sigmask: ret=%d", ret); } if (lttng_ust_comm_should_quit) { return -1; @@ -162,25 +180,21 @@ int ust_lock(void) void ust_lock_nocheck(void) { sigset_t sig_all_blocked, orig_mask; - int ret, oldstate; + int ret; - 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"); + if (lttng_ust_cancelstate_disable_push()) { + ERR("lttng_ust_cancelstate_disable_push"); } sigfillset(&sig_all_blocked); ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask); if (ret) { - ERR("pthread_sigmask: %s", strerror(ret)); + ERR("pthread_sigmask: ret=%d", 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)); + ERR("pthread_sigmask: ret=%d", ret); } } @@ -190,25 +204,21 @@ void ust_lock_nocheck(void) void ust_unlock(void) { sigset_t sig_all_blocked, orig_mask; - int ret, oldstate; + int ret; sigfillset(&sig_all_blocked); ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_mask); if (ret) { - ERR("pthread_sigmask: %s", strerror(ret)); + ERR("pthread_sigmask: ret=%d", 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)); + ERR("pthread_sigmask: ret=%d", ret); } - if (oldstate != PTHREAD_CANCEL_DISABLE) { - ERR("pthread_setcancelstate: unexpected oldstate"); + if (lttng_ust_cancelstate_disable_pop()) { + ERR("lttng_ust_cancelstate_disable_pop"); } } @@ -260,7 +270,7 @@ struct sock_info { int statedump_pending; int initial_statedump_done; /* Keep procname for statedump */ - char procname[LTTNG_UST_ABI_PROCNAME_LEN]; + char procname[LTTNG_UST_CONTEXT_PROCNAME_LEN]; }; /* Socket from app (connect) to session daemon (listen) for communication */ @@ -377,7 +387,7 @@ const char *get_lttng_home_dir(void) * Force a read (imply TLS allocation for dlopen) of TLS variables. */ static -void lttng_nest_count_alloc_tls(void) +void lttng_ust_nest_count_alloc_tls(void) { asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count))); } @@ -392,26 +402,26 @@ void lttng_ust_mutex_nest_alloc_tls(void) * Allocate lttng-ust urcu TLS. */ static -void lttng_lttng_ust_urcu_alloc_tls(void) +void lttng_ust_urcu_alloc_tls(void) { (void) lttng_ust_urcu_read_ongoing(); } -void lttng_ust_alloc_tls(void) +void lttng_ust_common_init_thread(int flags) { - lttng_lttng_ust_urcu_alloc_tls(); + lttng_ust_urcu_alloc_tls(); lttng_ringbuffer_alloc_tls(); - lttng_vtid_alloc_tls(); - lttng_nest_count_alloc_tls(); - lttng_procname_alloc_tls(); + lttng_ust_vtid_init_thread(flags); + lttng_ust_nest_count_alloc_tls(); + lttng_ust_procname_init_thread(flags); lttng_ust_mutex_nest_alloc_tls(); - lttng_ust_perf_counter_alloc_tls(); + lttng_ust_perf_counter_init_thread(flags); lttng_ust_common_alloc_tls(); - lttng_cgroup_ns_alloc_tls(); - lttng_ipc_ns_alloc_tls(); - lttng_net_ns_alloc_tls(); - lttng_time_ns_alloc_tls(); - lttng_uts_ns_alloc_tls(); + lttng_ust_cgroup_ns_init_thread(flags); + lttng_ust_ipc_ns_init_thread(flags); + lttng_ust_net_ns_init_thread(flags); + lttng_ust_time_ns_init_thread(flags); + lttng_ust_uts_ns_init_thread(flags); lttng_ust_ring_buffer_client_discard_alloc_tls(); lttng_ust_ring_buffer_client_discard_rt_alloc_tls(); lttng_ust_ring_buffer_client_overwrite_alloc_tls(); @@ -436,7 +446,9 @@ void lttng_ust_init_thread(void) * ensure those are initialized before a signal handler nesting over * this thread attempts to use them. */ - lttng_ust_alloc_tls(); + lttng_ust_common_init_thread(LTTNG_UST_INIT_THREAD_MASK); + + lttng_ust_urcu_register_thread(); } int lttng_get_notify_socket(void *owner) @@ -483,7 +495,7 @@ int setup_global_apps(void) } global_apps.allowed = 1; - lttng_pthread_getname_np(global_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN); + lttng_pthread_getname_np(global_apps.procname, LTTNG_UST_CONTEXT_PROCNAME_LEN); error: return ret; } @@ -529,7 +541,7 @@ int setup_local_apps(void) goto end; } - lttng_pthread_getname_np(local_apps.procname, LTTNG_UST_ABI_PROCNAME_LEN); + lttng_pthread_getname_np(local_apps.procname, LTTNG_UST_CONTEXT_PROCNAME_LEN); end: return ret; } @@ -621,7 +633,8 @@ void get_allow_blocking(void) } static -int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type) +int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type, + const char *procname) { return ustcomm_send_reg_msg(socket, type, @@ -630,7 +643,8 @@ int register_to_sessiond(int socket, enum lttng_ust_ctl_socket_type type) lttng_ust_rb_alignof(uint16_t) * CHAR_BIT, lttng_ust_rb_alignof(uint32_t) * CHAR_BIT, lttng_ust_rb_alignof(uint64_t) * CHAR_BIT, - lttng_ust_rb_alignof(unsigned long) * CHAR_BIT); + lttng_ust_rb_alignof(unsigned long) * CHAR_BIT, + procname); } static @@ -855,6 +869,49 @@ end: return ret; } +static +void prepare_cmd_reply(struct ustcomm_ust_reply *lur, uint32_t handle, uint32_t cmd, int ret) +{ + lur->handle = handle; + lur->cmd = 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; + } + } +} + static int handle_message(struct sock_info *sock_info, int sock, struct ustcomm_ust_msg *lum) @@ -879,6 +936,52 @@ int handle_message(struct sock_info *sock_info, goto error; } + switch (lum->cmd) { + case LTTNG_UST_ABI_FILTER: + case LTTNG_UST_ABI_EXCLUSION: + case LTTNG_UST_ABI_CHANNEL: + case LTTNG_UST_ABI_STREAM: + case LTTNG_UST_ABI_CONTEXT: + /* + * Those commands send additional payload after struct + * ustcomm_ust_msg, which makes it pretty much impossible to + * deal with "unknown command" errors without leaving the + * communication pipe in a out-of-sync state. This is part of + * the ABI between liblttng-ust-ctl and liblttng-ust, and + * should be fixed on the next breaking + * LTTNG_UST_ABI_MAJOR_VERSION protocol bump by indicating the + * total command message length as part of a message header so + * that the protocol can recover from invalid command errors. + */ + break; + + case LTTNG_UST_ABI_CAPTURE: + case LTTNG_UST_ABI_COUNTER: + case LTTNG_UST_ABI_COUNTER_GLOBAL: + case LTTNG_UST_ABI_COUNTER_CPU: + case LTTNG_UST_ABI_EVENT_NOTIFIER_CREATE: + case LTTNG_UST_ABI_EVENT_NOTIFIER_GROUP_CREATE: + /* + * Those commands expect a reply to the struct ustcomm_ust_msg + * before sending additional payload. + */ + prepare_cmd_reply(&lur, lum->handle, lum->cmd, 0); + + ret = send_reply(sock, &lur); + if (ret < 0) { + DBG("error sending reply"); + goto error; + } + break; + + default: + /* + * Other commands either don't send additional payload, or are + * unknown. + */ + break; + } + switch (lum->cmd) { case LTTNG_UST_ABI_REGISTER_DONE: if (lum->handle == LTTNG_UST_ABI_ROOT_HANDLE) @@ -1296,44 +1399,8 @@ int handle_message(struct sock_info *sock_info, 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; - } - } + prepare_cmd_reply(&lur, lum->handle, lum->cmd, ret); + if (ret >= 0) { switch (lum->cmd) { case LTTNG_UST_ABI_TRACER_VERSION: @@ -1405,8 +1472,7 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting) } 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 @@ -1418,6 +1484,9 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting) if (exiting) return; + sock_info->registration_done = 0; + sock_info->initial_statedump_done = 0; + if (sock_info->socket != -1) { ret = ustcomm_close_unix_sock(sock_info->socket); if (ret) { @@ -1690,18 +1759,25 @@ void wait_for_sessiond(struct sock_info *sock_info) 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 (lttng_ust_futex_async((int32_t *) sock_info->wait_shm_mmap, - FUTEX_WAIT, 0, NULL, NULL, 0)) { + while (!uatomic_read((int32_t *) sock_info->wait_shm_mmap)) { + if (!lttng_ust_futex_async((int32_t *) sock_info->wait_shm_mmap, FUTEX_WAIT, 0, NULL, NULL, 0)) { + /* + * Prior queued wakeups queued by unrelated code + * using the same address can cause futex wait to + * return 0 even through the futex value is still + * 0 (spurious wakeups). Check the value again + * in user-space to validate whether it really + * differs from 0. + */ + continue; + } switch (errno) { - case EWOULDBLOCK: + case EAGAIN: /* Value already changed. */ goto end_wait; case EINTR: /* Retry if interrupted by signal. */ - break; /* Get out of switch. */ + break; /* Get out of switch. Check again. */ case EFAULT: wait_poll_fallback = 1; DBG( @@ -1741,7 +1817,7 @@ void *ust_listener_thread(void *arg) int sock, ret, prev_connect_failed = 0, has_waited = 0, fd; long timeout; - lttng_ust_alloc_tls(); + lttng_ust_common_init_thread(0); /* * If available, add '-ust' to the end of this thread's * process name @@ -1859,7 +1935,8 @@ restart: sock_info->root_handle = ret; } - ret = register_to_sessiond(sock_info->socket, LTTNG_UST_CTL_SOCKET_CMD); + ret = register_to_sessiond(sock_info->socket, LTTNG_UST_CTL_SOCKET_CMD, + sock_info->procname); if (ret < 0) { ERR("Error registering to %s ust cmd socket", sock_info->name); @@ -1952,7 +2029,7 @@ restart: } ret = register_to_sessiond(sock_info->notify_socket, - LTTNG_UST_CTL_SOCKET_NOTIFY); + LTTNG_UST_CTL_SOCKET_NOTIFY, sock_info->procname); if (ret < 0) { ERR("Error registering to %s ust notify socket", sock_info->name); @@ -2048,6 +2125,41 @@ void lttng_ust_libc_wrapper_malloc_ctor(void) { } +/* + * Use a symbol of the previous ABI to detect if liblttng-ust.so.0 is loaded in + * the current process. + */ +#define LTTNG_UST_SONAME_0_SYM "ltt_probe_register" + +static +void lttng_ust_check_soname_0(void) +{ + if (!dlsym(RTLD_DEFAULT, LTTNG_UST_SONAME_0_SYM)) + return; + + CRIT("Incompatible library ABIs detected within the same process. " + "The process is likely linked against different major soname of LTTng-UST which is unsupported. " + "The detection was triggered by lookup of ABI 0 symbol \"%s\" in the Global Symbol Table\n", + LTTNG_UST_SONAME_0_SYM); +} + +/* + * Expose a canary symbol of the previous ABI to ensure we catch uses of a + * liblttng-ust.so.0 dlopen'd after .so.1 has been loaded. Use a different + * symbol than the detection code to ensure we don't detect ourself. + * + * This scheme will only work on systems where the global symbol table has + * priority when resolving the symbols of a dlopened shared object, which is + * the case on Linux but not on FreeBSD. + */ +void init_usterr(void); +void init_usterr(void) +{ + CRIT("Incompatible library ABIs detected within the same process. " + "The process is likely linked against different major soname of LTTng-UST which is unsupported. " + "The detection was triggered by canary symbol \"%s\"\n", __func__); +} + /* * sessiond monitoring thread: monitor presence of global and per-user * sessiond by polling the application common named pipe. @@ -2073,10 +2185,18 @@ void lttng_ust_ctor(void) * to be the dynamic linker mutex) and ust_lock, taken within * the ust lock. */ - lttng_ust_alloc_tls(); + lttng_ust_common_init_thread(0); lttng_ust_loaded = 1; + /* + * Check if we find a symbol of the previous ABI in the current process + * as different ABIs of liblttng-ust can't co-exist in a process. If we + * do so, emit a critical log message which will also abort if the + * LTTNG_UST_ABORT_ON_CRITICAL environment variable is set. + */ + lttng_ust_check_soname_0(); + /* * 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 @@ -2085,7 +2205,7 @@ void lttng_ust_ctor(void) * 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_SONAME library, calling dlopen will - * simply increment the refcount and no additionnal work is needed by the + * simply increment the refcount and no additional 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 @@ -2095,6 +2215,8 @@ void lttng_ust_ctor(void) handle = dlopen(LTTNG_UST_LIB_SONAME, RTLD_LAZY | RTLD_NODELETE); if (!handle) { ERR("dlopen of liblttng-ust shared library (%s).", LTTNG_UST_LIB_SONAME); + } else { + DBG("dlopened liblttng-ust shared library (%s).", LTTNG_UST_LIB_SONAME); } /* @@ -2118,8 +2240,6 @@ void lttng_ust_ctor(void) lttng_ust_common_ctor(); lttng_ust_tp_init(); - lttng_ust_clock_init(); - lttng_ust_getcpu_plugin_init(); lttng_ust_statedump_init(); lttng_ust_ring_buffer_clients_init(); lttng_ust_counter_clients_init(); @@ -2379,7 +2499,7 @@ void lttng_ust_before_fork(sigset_t *save_sigset) int ret; /* Allocate lttng-ust TLS. */ - lttng_ust_alloc_tls(); + lttng_ust_common_init_thread(0); if (URCU_TLS(lttng_ust_nest_count)) return; @@ -2422,7 +2542,7 @@ void lttng_ust_after_fork_parent(sigset_t *restore_sigset) return; DBG("process %d", getpid()); lttng_ust_urcu_after_fork_parent(); - /* Release mutexes and reenable signals */ + /* Release mutexes and re-enable signals */ ust_after_fork_common(restore_sigset); } @@ -2449,7 +2569,7 @@ void lttng_ust_after_fork_child(sigset_t *restore_sigset) /* Release urcu mutexes */ lttng_ust_urcu_after_fork_child(); lttng_ust_cleanup(0); - /* Release mutexes and reenable signals */ + /* Release mutexes and re-enable signals */ ust_after_fork_common(restore_sigset); lttng_ust_ctor(); }