/*
* SPDX-License-Identifier: LGPL-2.1-only
*
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 EfficiOS Inc.
* Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*/
#include <lttng/ust-libc-wrapper.h>
#include <lttng/ust-thread.h>
#include <lttng/ust-tracer.h>
+#include <lttng/ust-common.h>
+#include <lttng/ust-cancelstate.h>
#include <urcu/tls-compat.h>
-#include "common/compat/futex.h"
+#include "lib/lttng-ust/futex.h"
#include "common/ustcomm.h"
#include "common/ust-fd.h"
#include "common/logging.h"
#include "common/macros.h"
-#include "tracepoint-internal.h"
+#include "common/tracepoint.h"
#include "lttng-tracer-core.h"
#include "common/compat/pthread.h"
#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 ?
*/
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.
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;
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);
}
}
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");
}
}
*/
static sem_t constructor_wait;
/*
- * Doing this for both the global and local sessiond.
+ * Doing this for the ust_app, global and local sessiond.
*/
enum {
- sem_count_initial_value = 4,
+ sem_count_initial_value = 6,
};
static int sem_count = sem_count_initial_value;
int root_handle;
int registration_done;
int allowed;
- int global;
+ bool multi_user;
int thread_active;
char sock_path[PATH_MAX];
int socket;
int notify_socket;
+ /*
+ * If wait_shm_is_file is true, use standard open to open and
+ * create the shared memory used for waiting on session daemon.
+ * Otherwise, use shm_open to create this file.
+ */
+ bool wait_shm_is_file;
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;
/* 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 */
-struct sock_info global_apps = {
+static struct sock_info ust_app = {
+ .name = "ust_app",
+ .multi_user = true,
+
+ .root_handle = -1,
+ .registration_done = 0,
+ .allowed = 0,
+ .thread_active = 0,
+
+ .socket = -1,
+ .notify_socket = -1,
+
+ .wait_shm_is_file = true,
+
+ .statedump_pending = 0,
+ .initial_statedump_done = 0,
+ .procname[0] = '\0'
+};
+
+
+static struct sock_info global_apps = {
.name = "global",
- .global = 1,
+ .multi_user = true,
.root_handle = -1,
.registration_done = 0,
.socket = -1,
.notify_socket = -1,
+ .wait_shm_is_file = false,
.wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME,
.statedump_pending = 0,
.procname[0] = '\0'
};
-/* TODO: allow global_apps_sock_path override */
-
-struct sock_info local_apps = {
+static struct sock_info local_apps = {
.name = "local",
- .global = 0,
+ .multi_user = false,
.root_handle = -1,
.registration_done = 0,
.allowed = 0, /* Check setuid bit first */
.socket = -1,
.notify_socket = -1,
+ .wait_shm_is_file = false,
+
.statedump_pending = 0,
.initial_statedump_done = 0,
.procname[0] = '\0'
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.
}
/*
- * Force a read (imply TLS fixup for dlopen) of TLS variables.
+ * Returns the LTTNG_UST_APP_PATH path. If environment variable exists
+ * and contains a ':', the first path before the ':' separator is returned.
+ * The return value should be freed by the caller if it is not NULL.
+ */
+static
+char *get_lttng_ust_app_path(void)
+{
+ const char *env_val = lttng_ust_getenv("LTTNG_UST_APP_PATH");
+ char *val = NULL;
+ char *sep = NULL;
+ if (env_val == NULL)
+ goto error;
+ sep = strchr((char*)env_val, ':');
+ if (sep) {
+ /*
+ * Split into multiple paths using ':' as a separator.
+ * There is no escaping of the ':' separator.
+ */
+ WARN("':' separator in LTTNG_UST_APP_PATH, only the first path will be used.");
+ val = zmalloc(sep - env_val + 1);
+ if (!val) {
+ PERROR("zmalloc get_lttng_ust_app_path");
+ goto error;
+ }
+ memcpy(val, env_val, sep - env_val);
+ val[sep - env_val] = '\0';
+ } else {
+ val = strdup(env_val);
+ if (!val) {
+ PERROR("strdup");
+ goto error;
+ }
+ }
+
+error:
+ return val;
+}
+
+/*
+ * Force a read (imply TLS allocation for dlopen) of TLS variables.
*/
static
-void lttng_fixup_nest_count_tls(void)
+void lttng_ust_nest_count_alloc_tls(void)
{
- asm volatile ("" : : "m" (URCU_TLS(lttng_ust_nest_count)));
+ __asm__ __volatile__ ("" : : "m" (URCU_TLS(lttng_ust_nest_count)));
}
static
-void lttng_fixup_ust_mutex_nest_tls(void)
+void lttng_ust_mutex_nest_alloc_tls(void)
{
- asm volatile ("" : : "m" (URCU_TLS(ust_mutex_nest)));
+ __asm__ __volatile__ ("" : : "m" (URCU_TLS(ust_mutex_nest)));
}
/*
- * Fixup lttng-ust urcu TLS.
+ * Allocate lttng-ust urcu TLS.
*/
static
-void lttng_fixup_lttng_ust_urcu_tls(void)
+void lttng_ust_urcu_alloc_tls(void)
{
(void) lttng_ust_urcu_read_ongoing();
}
-void lttng_ust_fixup_tls(void)
+void lttng_ust_common_init_thread(int flags)
{
- lttng_fixup_lttng_ust_urcu_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();
- lttng_fixup_cgroup_ns_tls();
- lttng_fixup_ipc_ns_tls();
- lttng_fixup_net_ns_tls();
- lttng_fixup_time_ns_tls();
- lttng_fixup_uts_ns_tls();
- lttng_ust_fixup_ring_buffer_client_discard_tls();
- lttng_ust_fixup_ring_buffer_client_discard_rt_tls();
- lttng_ust_fixup_ring_buffer_client_overwrite_tls();
- lttng_ust_fixup_ring_buffer_client_overwrite_rt_tls();
+ lttng_ust_urcu_alloc_tls();
+ lttng_ringbuffer_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_init_thread(flags);
+ lttng_ust_common_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();
+ lttng_ust_ring_buffer_client_overwrite_rt_alloc_tls();
}
/*
* ensure those are initialized before a signal handler nesting over
* this thread attempts to use them.
*/
- lttng_ust_fixup_tls();
+ lttng_ust_common_init_thread(LTTNG_UST_INIT_THREAD_MASK);
+
+ lttng_ust_urcu_register_thread();
}
int lttng_get_notify_socket(void *owner)
lttng_ust_obj_get_name(handle), handle);
}
+static
+int setup_ust_apps(void)
+{
+ char *ust_app_path = NULL;
+ int ret = 0;
+ uid_t uid;
+
+ assert(!ust_app.wait_shm_mmap);
+
+ uid = getuid();
+ /*
+ * Disallow ust apps tracing for setuid binaries, because we
+ * cannot use the environment variables anyway.
+ */
+ if (uid != geteuid()) {
+ DBG("UST app tracing disabled for setuid binary.");
+ assert(ust_app.allowed == 0);
+ ret = 0;
+ goto end;
+ }
+ ust_app_path = get_lttng_ust_app_path();
+ if (!ust_app_path) {
+ DBG("LTTNG_UST_APP_PATH environment variable not set.");
+ assert(ust_app.allowed == 0);
+ ret = -ENOENT;
+ goto end;
+ }
+ /*
+ * The LTTNG_UST_APP_PATH env. var. disables global and local
+ * sessiond connections.
+ */
+ ust_app.allowed = 1;
+ snprintf(ust_app.sock_path, PATH_MAX, "%s/%s",
+ ust_app_path, LTTNG_UST_SOCK_FILENAME);
+ snprintf(ust_app.wait_shm_path, PATH_MAX, "%s/%s",
+ ust_app_path,
+ LTTNG_UST_WAIT_FILENAME);
+
+ ust_app.wait_shm_mmap = get_map_shm(&ust_app);
+ if (!ust_app.wait_shm_mmap) {
+ WARN("Unable to get map shm for ust_app. Disabling LTTng-UST ust_app tracing.");
+ ust_app.allowed = 0;
+ ret = -EIO;
+ goto end;
+ }
+
+ lttng_pthread_getname_np(ust_app.procname, LTTNG_UST_CONTEXT_PROCNAME_LEN);
+end:
+ if (ust_app_path)
+ free(ust_app_path);
+ return ret;
+}
+
static
int setup_global_apps(void)
{
int ret = 0;
assert(!global_apps.wait_shm_mmap);
+ /*
+ * The LTTNG_UST_APP_PATH env. var. disables global sessiond
+ * connections.
+ */
+ if (ust_app.allowed)
+ return 0;
+
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 = 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;
}
+
static
int setup_local_apps(void)
{
assert(!local_apps.wait_shm_mmap);
+ /*
+ * The LTTNG_UST_APP_PATH env. var. disables local sessiond
+ * connections.
+ */
+ if (ust_app.allowed)
+ return 0;
+
uid = getuid();
/*
* Disallow per-user tracing for setuid binaries.
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;
}
}
static
-int register_to_sessiond(int socket, enum ustctl_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,
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
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)
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)
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:
}
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
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) {
}
}
+static
+int wait_shm_open(struct sock_info *sock_info, int flags, mode_t mode)
+{
+ if (sock_info->wait_shm_is_file)
+ return open(sock_info->wait_shm_path, flags, mode);
+ else
+ return shm_open(sock_info->wait_shm_path, flags, mode);
+}
+
/*
* 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
/*
* Try to open read-only.
*/
- wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0);
+ wait_shm_fd = wait_shm_open(sock_info, O_RDONLY, 0);
if (wait_shm_fd >= 0) {
int32_t tmp_read;
ssize_t len;
pid = fork();
URCU_TLS(lttng_ust_nest_count)--;
if (pid > 0) {
- int status;
+ int status, wait_ret;
/*
* 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_ret = waitpid(pid, &status, 0);
+ if (wait_ret < 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);
+ wait_shm_fd = wait_shm_open(sock_info, O_RDONLY, 0);
if (wait_shm_fd < 0) {
/*
* Real-only open did not work. It's a failure
/* Child */
create_mode = S_IRUSR | S_IWUSR | S_IRGRP;
- if (sock_info->global)
+ if (sock_info->multi_user)
create_mode |= S_IROTH | S_IWGRP | S_IWOTH;
/*
* We're alone in a child process, so we can modify the
* 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,
+ wait_shm_fd = wait_shm_open(sock_info,
O_RDWR | O_CREAT, create_mode);
if (wait_shm_fd >= 0) {
ret = ftruncate(wait_shm_fd, mmap_size);
* sessiond will be able to override all rights and wake
* us up.
*/
- if (!sock_info->global && errno != EACCES) {
+ if (!sock_info->multi_user && errno != EACCES) {
ERR("Error opening shm %s", sock_info->wait_shm_path);
_exit(EXIT_FAILURE);
}
return -1;
}
end:
- if (wait_shm_fd >= 0 && !sock_info->global) {
+ if (wait_shm_fd >= 0 && !sock_info->multi_user) {
struct stat statbuf;
/*
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(
int sock, ret, prev_connect_failed = 0, has_waited = 0, fd;
long timeout;
- lttng_ust_fixup_tls();
+ lttng_ust_common_init_thread(0);
/*
* If available, add '-ust' to the end of this thread's
* process name
sock_info->root_handle = ret;
}
- ret = register_to_sessiond(sock_info->socket, USTCTL_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);
}
ret = register_to_sessiond(sock_info->notify_socket,
- USTCTL_SOCKET_NOTIFY);
+ LTTNG_UST_CTL_SOCKET_NOTIFY, sock_info->procname);
if (ret < 0) {
ERR("Error registering to %s ust notify socket",
sock_info->name);
* Weak symbol to call when the ust malloc wrapper is not loaded.
*/
__attribute__((weak))
-void lttng_ust_libc_wrapper_malloc_init(void)
+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 by polling the application common named pipe.
*/
static
-void lttng_ust_init(void)
+void lttng_ust_ctor(void)
__attribute__((constructor));
static
-void lttng_ust_init(void)
+void lttng_ust_ctor(void)
{
struct timespec constructor_timeout;
sigset_t sig_all_blocked, orig_parent_mask;
return;
/*
- * Fixup interdependency between TLS fixup mutex (which happens
+ * Fixup interdependency between TLS allocation mutex (which happens
* to be the dynamic linker mutex) and ust_lock, taken within
* the ust lock.
*/
- lttng_ust_fixup_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
* 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
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);
}
/*
* sessiond (otherwise leading to errors when trying to create
* sessiond before the init functions are completed).
*/
+
+ /*
+ * Both the logging and getenv lazy-initialization uses getenv()
+ * internally and thus needs to be explicitly initialized in
+ * liblttng-ust before we start any threads as an unsuspecting normally
+ * single threaded application using liblttng-ust could be using
+ * setenv() which is not thread-safe.
+ */
lttng_ust_logging_init();
- lttng_ust_getenv_init(); /* Needs lttng_ust_logging_init() to be completed. */
+ lttng_ust_getenv_init();
+
+ /* Call the liblttng-ust-common constructor. */
+ lttng_ust_common_ctor();
+
lttng_ust_tp_init();
- lttng_ust_init_fd_tracker();
- lttng_ust_clock_init();
- lttng_ust_getcpu_plugin_init();
lttng_ust_statedump_init();
lttng_ust_ring_buffer_clients_init();
lttng_ust_counter_clients_init();
/*
* Invoke ust malloc wrapper init before starting other threads.
*/
- lttng_ust_libc_wrapper_malloc_init();
+ lttng_ust_libc_wrapper_malloc_ctor();
timeout_mode = get_constructor_timeout(&constructor_timeout);
PERROR("sem_init");
}
+ ret = setup_ust_apps();
+ if (ret) {
+ assert(ust_app.allowed == 0);
+ DBG("ust_app setup returned %d", ret);
+ }
ret = setup_global_apps();
if (ret) {
assert(global_apps.allowed == 0);
ERR("pthread_attr_setdetachstate: %s", strerror(ret));
}
+ if (ust_app.allowed) {
+ pthread_mutex_lock(&ust_exit_mutex);
+ ret = pthread_create(&ust_app.ust_listener, &thread_attr,
+ ust_listener_thread, &ust_app);
+ if (ret) {
+ ERR("pthread_create ust_app: %s", strerror(ret));
+ }
+ ust_app.thread_active = 1;
+ pthread_mutex_unlock(&ust_exit_mutex);
+ } else {
+ handle_register_done(&ust_app);
+ }
+
if (global_apps.allowed) {
pthread_mutex_lock(&ust_exit_mutex);
ret = pthread_create(&global_apps.ust_listener, &thread_attr,
static
void lttng_ust_cleanup(int exiting)
{
+ cleanup_sock_info(&ust_app, exiting);
cleanup_sock_info(&global_apps, exiting);
cleanup_sock_info(&local_apps, exiting);
+ ust_app.allowed = 0;
local_apps.allowed = 0;
global_apps.allowed = 0;
/*
pthread_mutex_lock(&ust_exit_mutex);
/* cancel threads */
+ if (ust_app.thread_active) {
+ ret = pthread_cancel(ust_app.ust_listener);
+ if (ret) {
+ ERR("Error cancelling ust listener thread: %s",
+ strerror(ret));
+ } else {
+ ust_app.thread_active = 0;
+ }
+ }
if (global_apps.thread_active) {
ret = pthread_cancel(global_apps.ust_listener);
if (ret) {
sigset_t all_sigs;
int ret;
- /* Fixup lttng-ust TLS. */
- lttng_ust_fixup_tls();
+ /* Allocate lttng-ust TLS. */
+ lttng_ust_common_init_thread(0);
if (URCU_TLS(lttng_ust_nest_count))
return;
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);
}
* 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.
+ * lttng_ust_ctor() 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).
/* 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_init();
+ lttng_ust_ctor();
}
void lttng_ust_after_setns(void)
projects / lttng-ust.git / blobdiff