X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=a299ba84c6ba583b1d2afff4d8ff0576a0991e36;hb=61e520fbc01329423ff3f80be7171eb48cabd085;hp=32ba3c1d49e2ba7bbec27ffb2f0d3f502d168653;hpb=f5c453e975e5d417590b9a1be2a9f8504db063c0;p=lttng-ust.git diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index 32ba3c1d..a299ba84 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -59,6 +60,9 @@ #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 ? */ @@ -260,7 +264,7 @@ struct sock_info global_apps = { .global = 1, .root_handle = -1, - .allowed = 1, + .allowed = 0, .thread_active = 0, .sock_path = LTTNG_DEFAULT_RUNDIR "/" LTTNG_UST_SOCK_FILENAME, @@ -339,6 +343,8 @@ 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; @@ -430,25 +436,48 @@ void print_cmd(int cmd, int handle) 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); - return 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); - return -ENOENT; + ret = -ENOENT; + goto end; } local_apps.allowed = 1; snprintf(local_apps.sock_path, PATH_MAX, "%s/%s/%s", @@ -458,7 +487,16 @@ int setup_local_apps(void) snprintf(local_apps.wait_shm_path, PATH_MAX, "/%s-%u", LTTNG_UST_WAIT_FILENAME, uid); - return 0; + + 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; } /* @@ -839,12 +877,13 @@ int handle_message(struct sock_info *sock_info, { /* Receive shm_fd, wakeup_fd */ ret = ustcomm_recv_stream_from_sessiond(sock, - &lum->u.stream.len, + 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, @@ -1301,19 +1340,17 @@ error: 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; } - 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(); + 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)) @@ -1396,6 +1433,10 @@ restart: 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); @@ -1415,9 +1456,6 @@ restart: sock_info->notify_socket = -1; } - if (ust_lock()) { - goto quit; - } /* * Register. We need to perform both connect and sending @@ -1684,6 +1722,7 @@ void __attribute__((constructor)) lttng_ust_init(void) pthread_attr_t thread_attr; int timeout_mode; int ret; + void *handle; if (uatomic_xchg(&initialized, 1) == 1) return; @@ -1697,6 +1736,26 @@ void __attribute__((constructor)) lttng_ust_init(void) 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 @@ -1730,8 +1789,15 @@ void __attribute__((constructor)) lttng_ust_init(void) 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); } @@ -1755,14 +1821,18 @@ void __attribute__((constructor)) lttng_ust_init(void) ERR("pthread_attr_setdetachstate: %s", strerror(ret)); } - 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)); + 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); } - global_apps.thread_active = 1; - pthread_mutex_unlock(&ust_exit_mutex); if (local_apps.allowed) { pthread_mutex_lock(&ust_exit_mutex); @@ -1833,6 +1903,7 @@ 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 @@ -1943,7 +2014,7 @@ void ust_before_fork(sigset_t *save_sigset) pthread_mutex_lock(&ust_fork_mutex); ust_lock_nocheck(); - rcu_bp_before_fork(); + urcu_bp_before_fork(); } static void ust_after_fork_common(sigset_t *restore_sigset) @@ -1967,7 +2038,7 @@ void ust_after_fork_parent(sigset_t *restore_sigset) if (URCU_TLS(lttng_ust_nest_count)) return; DBG("process %d", getpid()); - rcu_bp_after_fork_parent(); + urcu_bp_after_fork_parent(); /* Release mutexes and reenable signals */ ust_after_fork_common(restore_sigset); } @@ -1985,10 +2056,12 @@ 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 */ - rcu_bp_after_fork_child(); + urcu_bp_after_fork_child(); lttng_ust_cleanup(0); /* Release mutexes and reenable signals */ ust_after_fork_common(restore_sigset);