X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Flttng-ust-comm.c;h=838bf08bfea43d609fb749814ab2ae68e758b468;hb=b4051ad8c170901d5297e1b3005b24e63cb0ab1e;hp=61dbb41b4553c9a9eee21829ba269e4d5c93c1cb;hpb=060577e34998f721439135e8fc533a0e52d98ff1;p=lttng-ust.git diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index 61dbb41b..838bf08b 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -21,6 +21,7 @@ #define _LGPL_SOURCE #define _GNU_SOURCE +#include #include #include #include @@ -86,6 +87,8 @@ static int initialized; * * ust_lock nests within the dynamic loader lock (within glibc) because * it is taken within the library constructor. + * + * The ust fd tracker lock nests within the ust_mutex. */ static pthread_mutex_t ust_mutex = PTHREAD_MUTEX_INITIALIZER; @@ -228,7 +231,11 @@ static sem_t constructor_wait; /* * Doing this for both the global and local sessiond. */ -static int sem_count = { 2 }; +enum { + sem_count_initial_value = 4, +}; + +static int sem_count = sem_count_initial_value; /* * Counting nesting within lttng-ust. Used to ensure that calling fork() @@ -243,7 +250,7 @@ struct sock_info { const char *name; pthread_t ust_listener; /* listener thread */ int root_handle; - int constructor_sem_posted; + int registration_done; int allowed; int global; int thread_active; @@ -256,6 +263,9 @@ struct sock_info { 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_PROCNAME_LEN]; }; /* Socket from app (connect) to session daemon (listen) for communication */ @@ -264,6 +274,7 @@ struct sock_info global_apps = { .global = 1, .root_handle = -1, + .registration_done = 0, .allowed = 0, .thread_active = 0, @@ -274,6 +285,8 @@ struct sock_info global_apps = { .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME, .statedump_pending = 0, + .initial_statedump_done = 0, + .procname[0] = '\0' }; /* TODO: allow global_apps_sock_path override */ @@ -282,6 +295,7 @@ struct sock_info local_apps = { .name = "local", .global = 0, .root_handle = -1, + .registration_done = 0, .allowed = 0, /* Check setuid bit first */ .thread_active = 0, @@ -289,6 +303,8 @@ struct sock_info local_apps = { .notify_socket = -1, .statedump_pending = 0, + .initial_statedump_done = 0, + .procname[0] = '\0' }; static int wait_poll_fallback; @@ -412,7 +428,12 @@ void lttng_ust_fixup_tls(void) 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_uts_ns_tls(); } int lttng_get_notify_socket(void *owner) @@ -422,6 +443,15 @@ int lttng_get_notify_socket(void *owner) return info->notify_socket; } + +LTTNG_HIDDEN +char* lttng_ust_sockinfo_get_procname(void *owner) +{ + struct sock_info *info = owner; + + return info->procname; +} + static void print_cmd(int cmd, int handle) { @@ -451,6 +481,7 @@ int setup_global_apps(void) } global_apps.allowed = 1; + lttng_ust_getprocname(global_apps.procname); error: return ret; } @@ -495,6 +526,8 @@ int setup_local_apps(void) ret = -EIO; goto end; } + + lttng_ust_getprocname(local_apps.procname); end: return ret; } @@ -621,45 +654,85 @@ int send_reply(int sock, struct ustcomm_ust_reply *lur) } static -int handle_register_done(struct sock_info *sock_info) +void decrement_sem_count(unsigned int count) { int ret; - if (sock_info->constructor_sem_posted) - return 0; - sock_info->constructor_sem_posted = 1; + assert(uatomic_read(&sem_count) >= count); + if (uatomic_read(&sem_count) <= 0) { - return 0; + return; } - ret = uatomic_add_return(&sem_count, -1); + + ret = uatomic_add_return(&sem_count, -count); if (ret == 0) { ret = sem_post(&constructor_wait); assert(!ret); } +} + +static +int handle_register_done(struct sock_info *sock_info) +{ + if (sock_info->registration_done) + return 0; + sock_info->registration_done = 1; + + decrement_sem_count(1); + if (!sock_info->statedump_pending) { + sock_info->initial_statedump_done = 1; + decrement_sem_count(1); + } + + return 0; +} + +static +int handle_register_failed(struct sock_info *sock_info) +{ + if (sock_info->registration_done) + return 0; + sock_info->registration_done = 1; + sock_info->initial_statedump_done = 1; + + decrement_sem_count(2); + return 0; } /* * Only execute pending statedump after the constructor semaphore has - * been posted by each listener thread. This means statedump will only - * be performed after the "registration done" command is received from - * each session daemon the application is connected to. + * been posted by the current listener thread. This means statedump will + * only be performed after the "registration done" command is received + * from this thread's session daemon. * * This ensures we don't run into deadlock issues with the dynamic * loader mutex, which is held while the constructor is called and * waiting on the constructor semaphore. All operations requiring this * dynamic loader lock need to be postponed using this mechanism. + * + * In a scenario with two session daemons connected to the application, + * it is possible that the first listener thread which receives the + * registration done command issues its statedump while the dynamic + * loader lock is still held by the application constructor waiting on + * the semaphore. It will however be allowed to proceed when the + * second session daemon sends the registration done command to the + * second listener thread. This situation therefore does not produce + * a deadlock. */ static void handle_pending_statedump(struct sock_info *sock_info) { - int ctor_passed = sock_info->constructor_sem_posted; - - if (ctor_passed && sock_info->statedump_pending) { + if (sock_info->registration_done && sock_info->statedump_pending) { sock_info->statedump_pending = 0; pthread_mutex_lock(&ust_fork_mutex); lttng_handle_pending_statedump(sock_info); pthread_mutex_unlock(&ust_fork_mutex); + + if (!sock_info->initial_statedump_done) { + sock_info->initial_statedump_done = 1; + decrement_sem_count(1); + } } } @@ -877,12 +950,13 @@ 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, @@ -1068,7 +1142,8 @@ void cleanup_sock_info(struct sock_info *sock_info, int exiting) } sock_info->root_handle = -1; } - sock_info->constructor_sem_posted = 0; + sock_info->registration_done = 0; + sock_info->initial_statedump_done = 0; /* * wait_shm_mmap, socket and notify socket are used by listener @@ -1476,7 +1551,7 @@ restart: * If we cannot find the sessiond daemon, don't delay * constructor execution. */ - ret = handle_register_done(sock_info); + ret = handle_register_failed(sock_info); assert(!ret); ust_unlock(); goto restart; @@ -1530,7 +1605,7 @@ restart: * If we cannot register to the sessiond daemon, don't * delay constructor execution. */ - ret = handle_register_done(sock_info); + ret = handle_register_failed(sock_info); assert(!ret); ust_unlock(); goto restart; @@ -1559,7 +1634,7 @@ restart: * If we cannot find the sessiond daemon, don't delay * constructor execution. */ - ret = handle_register_done(sock_info); + ret = handle_register_failed(sock_info); assert(!ret); ust_unlock(); goto restart; @@ -1623,7 +1698,7 @@ restart: * If we cannot register to the sessiond daemon, don't * delay constructor execution. */ - ret = handle_register_done(sock_info); + ret = handle_register_failed(sock_info); assert(!ret); ust_unlock(); goto restart; @@ -1653,7 +1728,7 @@ restart: * If we cannot register to the sessiond daemon, don't * delay constructor execution. */ - ret = handle_register_done(sock_info); + ret = handle_register_failed(sock_info); assert(!ret); ust_unlock(); goto end; @@ -1922,7 +1997,7 @@ void lttng_ust_cleanup(int exiting) exit_tracepoint(); if (!exiting) { /* Reinitialize values for fork */ - sem_count = 2; + sem_count = sem_count_initial_value; lttng_ust_comm_should_quit = 0; initialized = 0; } @@ -1980,6 +2055,34 @@ void __attribute__((destructor)) lttng_ust_exit(void) lttng_ust_cleanup(1); } +static +void ust_context_ns_reset(void) +{ + lttng_context_pid_ns_reset(); + lttng_context_cgroup_ns_reset(); + lttng_context_ipc_ns_reset(); + lttng_context_mnt_ns_reset(); + lttng_context_net_ns_reset(); + lttng_context_user_ns_reset(); + lttng_context_uts_ns_reset(); +} + +static +void ust_context_vuids_reset(void) +{ + lttng_context_vuid_reset(); + lttng_context_veuid_reset(); + lttng_context_vsuid_reset(); +} + +static +void ust_context_vgids_reset(void) +{ + lttng_context_vgid_reset(); + lttng_context_vegid_reset(); + lttng_context_vsgid_reset(); +} + /* * We exclude the worker threads across fork and clone (except * CLONE_VM), because these system calls only keep the forking thread @@ -2014,6 +2117,8 @@ void ust_before_fork(sigset_t *save_sigset) ust_lock_nocheck(); urcu_bp_before_fork(); + lttng_ust_lock_fd_tracker(); + lttng_perf_lock(); } static void ust_after_fork_common(sigset_t *restore_sigset) @@ -2021,6 +2126,8 @@ static void ust_after_fork_common(sigset_t *restore_sigset) int ret; DBG("process %d", getpid()); + lttng_perf_unlock(); + lttng_ust_unlock_fd_tracker(); ust_unlock(); pthread_mutex_unlock(&ust_fork_mutex); @@ -2058,6 +2165,9 @@ void ust_after_fork_child(sigset_t *restore_sigset) lttng_context_vpid_reset(); lttng_context_vtid_reset(); lttng_context_procname_reset(); + ust_context_ns_reset(); + ust_context_vuids_reset(); + ust_context_vgids_reset(); DBG("process %d", getpid()); /* Release urcu mutexes */ urcu_bp_after_fork_child(); @@ -2067,6 +2177,60 @@ void ust_after_fork_child(sigset_t *restore_sigset) lttng_ust_init(); } +void ust_after_setns(void) +{ + ust_context_ns_reset(); + ust_context_vuids_reset(); + ust_context_vgids_reset(); +} + +void ust_after_unshare(void) +{ + ust_context_ns_reset(); + ust_context_vuids_reset(); + ust_context_vgids_reset(); +} + +void ust_after_setuid(void) +{ + ust_context_vuids_reset(); +} + +void ust_after_seteuid(void) +{ + ust_context_vuids_reset(); +} + +void ust_after_setreuid(void) +{ + ust_context_vuids_reset(); +} + +void ust_after_setresuid(void) +{ + ust_context_vuids_reset(); +} + +void ust_after_setgid(void) +{ + ust_context_vgids_reset(); +} + +void ust_after_setegid(void) +{ + ust_context_vgids_reset(); +} + +void ust_after_setregid(void) +{ + ust_context_vgids_reset(); +} + +void ust_after_setresgid(void) +{ + ust_context_vgids_reset(); +} + void lttng_ust_sockinfo_session_enabled(void *owner) { struct sock_info *sock_info = owner;