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Diffstat (limited to '')
| -rw-r--r-- | spawn/spawn.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/spawn/spawn.c b/spawn/spawn.c new file mode 100644 index 000000000..256c04679 --- /dev/null +++ b/spawn/spawn.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-3.0-or-later + +#include "spawn.h" +#include "../database/engine/rrdenginelib.h" + +static uv_thread_t thread; +int spawn_thread_error; +int spawn_thread_shutdown; + +struct spawn_queue spawn_cmd_queue; + +static struct spawn_cmd_info *create_spawn_cmd(char *command_to_run) +{ + struct spawn_cmd_info *cmdinfo; + + cmdinfo = mallocz(sizeof(*cmdinfo)); + fatal_assert(0 == uv_cond_init(&cmdinfo->cond)); + fatal_assert(0 == uv_mutex_init(&cmdinfo->mutex)); + cmdinfo->serial = 0; /* invalid */ + cmdinfo->command_to_run = strdupz(command_to_run); + cmdinfo->exit_status = -1; /* invalid */ + cmdinfo->pid = -1; /* invalid */ + cmdinfo->flags = 0; + + return cmdinfo; +} + +void destroy_spawn_cmd(struct spawn_cmd_info *cmdinfo) +{ + uv_cond_destroy(&cmdinfo->cond); + uv_mutex_destroy(&cmdinfo->mutex); + + freez(cmdinfo->command_to_run); + freez(cmdinfo); +} + +int spawn_cmd_compare(void *a, void *b) +{ + struct spawn_cmd_info *cmda = a, *cmdb = b; + + /* No need for mutex, serial will never change and the entries cannot be deallocated yet */ + if (cmda->serial < cmdb->serial) return -1; + if (cmda->serial > cmdb->serial) return 1; + + return 0; +} + +static void init_spawn_cmd_queue(void) +{ + spawn_cmd_queue.cmd_tree.root = NULL; + spawn_cmd_queue.cmd_tree.compar = spawn_cmd_compare; + spawn_cmd_queue.size = 0; + spawn_cmd_queue.latest_serial = 0; + fatal_assert(0 == uv_cond_init(&spawn_cmd_queue.cond)); + fatal_assert(0 == uv_mutex_init(&spawn_cmd_queue.mutex)); +} + +/* + * Returns serial number of the enqueued command + */ +uint64_t spawn_enq_cmd(char *command_to_run) +{ + unsigned queue_size; + uint64_t serial; + avl *avl_ret; + struct spawn_cmd_info *cmdinfo; + + cmdinfo = create_spawn_cmd(command_to_run); + + /* wait for free space in queue */ + uv_mutex_lock(&spawn_cmd_queue.mutex); + while ((queue_size = spawn_cmd_queue.size) == SPAWN_MAX_OUTSTANDING) { + uv_cond_wait(&spawn_cmd_queue.cond, &spawn_cmd_queue.mutex); + } + fatal_assert(queue_size < SPAWN_MAX_OUTSTANDING); + spawn_cmd_queue.size = queue_size + 1; + + serial = ++spawn_cmd_queue.latest_serial; /* 0 is invalid */ + cmdinfo->serial = serial; /* No need to take the cmd mutex since it is unreachable at the moment */ + + /* enqueue command */ + avl_ret = avl_insert(&spawn_cmd_queue.cmd_tree, (avl *)cmdinfo); + fatal_assert(avl_ret == (avl *)cmdinfo); + uv_mutex_unlock(&spawn_cmd_queue.mutex); + + /* wake up event loop */ + fatal_assert(0 == uv_async_send(&spawn_async)); + return serial; +} + +/* + * Blocks until command with serial finishes running. Only one thread is allowed to wait per command. + */ +void spawn_wait_cmd(uint64_t serial, int *exit_status, time_t *exec_run_timestamp) +{ + avl *avl_ret; + struct spawn_cmd_info tmp, *cmdinfo; + + tmp.serial = serial; + + uv_mutex_lock(&spawn_cmd_queue.mutex); + avl_ret = avl_search(&spawn_cmd_queue.cmd_tree, (avl *)&tmp); + uv_mutex_unlock(&spawn_cmd_queue.mutex); + + fatal_assert(avl_ret); /* Could be NULL if more than 1 threads wait for the command */ + cmdinfo = (struct spawn_cmd_info *)avl_ret; + + uv_mutex_lock(&cmdinfo->mutex); + while (!(cmdinfo->flags & SPAWN_CMD_DONE)) { + /* Only 1 thread is allowed to wait for this command to finish */ + uv_cond_wait(&cmdinfo->cond, &cmdinfo->mutex); + } + uv_mutex_unlock(&cmdinfo->mutex); + + spawn_deq_cmd(cmdinfo); + *exit_status = cmdinfo->exit_status; + *exec_run_timestamp = cmdinfo->exec_run_timestamp; + + destroy_spawn_cmd(cmdinfo); +} + +void spawn_deq_cmd(struct spawn_cmd_info *cmdinfo) +{ + unsigned queue_size; + avl *avl_ret; + + uv_mutex_lock(&spawn_cmd_queue.mutex); + queue_size = spawn_cmd_queue.size; + fatal_assert(queue_size); + /* dequeue command */ + avl_ret = avl_remove(&spawn_cmd_queue.cmd_tree, (avl *)cmdinfo); + fatal_assert(avl_ret); + + spawn_cmd_queue.size = queue_size - 1; + + /* wake up callers */ + uv_cond_signal(&spawn_cmd_queue.cond); + uv_mutex_unlock(&spawn_cmd_queue.mutex); +} + +/* + * Must be called from the spawn client event loop context. This way no mutex is needed because the event loop is the + * only writer as far as struct spawn_cmd_info entries are concerned. + */ +static int find_unprocessed_spawn_cmd_cb(void *entry, void *data) +{ + struct spawn_cmd_info **cmdinfop = data, *cmdinfo = entry; + + if (!(cmdinfo->flags & SPAWN_CMD_PROCESSED)) { + *cmdinfop = cmdinfo; + return -1; /* break tree traversal */ + } + return 0; /* continue traversing */ +} + +struct spawn_cmd_info *spawn_get_unprocessed_cmd(void) +{ + struct spawn_cmd_info *cmdinfo; + unsigned queue_size; + int ret; + + uv_mutex_lock(&spawn_cmd_queue.mutex); + queue_size = spawn_cmd_queue.size; + if (queue_size == 0) { + uv_mutex_unlock(&spawn_cmd_queue.mutex); + return NULL; + } + /* find command */ + cmdinfo = NULL; + ret = avl_traverse(&spawn_cmd_queue.cmd_tree, find_unprocessed_spawn_cmd_cb, (void *)&cmdinfo); + if (-1 != ret) { /* no commands available for processing */ + uv_mutex_unlock(&spawn_cmd_queue.mutex); + return NULL; + } + uv_mutex_unlock(&spawn_cmd_queue.mutex); + + return cmdinfo; +} + +/** + * This function spawns a process that shares a libuv IPC pipe with the caller and performs spawn server duties. + * The spawn server process will close all open file descriptors except for the pipe, UV_STDOUT_FD, and UV_STDERR_FD. + * The caller has to be the netdata user as configured. + * + * @param loop the libuv loop of the caller context + * @param spawn_channel the birectional libuv IPC pipe that the server and the caller will share + * @param process the spawn server libuv process context + * @return 0 on success or the libuv error code + */ +int create_spawn_server(uv_loop_t *loop, uv_pipe_t *spawn_channel, uv_process_t *process) +{ + uv_process_options_t options = {0}; + char *args[3]; + int ret; +#define SPAWN_SERVER_DESCRIPTORS (3) + uv_stdio_container_t stdio[SPAWN_SERVER_DESCRIPTORS]; + struct passwd *passwd = NULL; + char *user = NULL; + + passwd = getpwuid(getuid()); + user = (passwd && passwd->pw_name) ? passwd->pw_name : ""; + + args[0] = exepath; + args[1] = SPAWN_SERVER_COMMAND_LINE_ARGUMENT; + args[2] = NULL; + + memset(&options, 0, sizeof(options)); + options.file = exepath; + options.args = args; + options.exit_cb = NULL; //exit_cb; + options.stdio = stdio; + options.stdio_count = SPAWN_SERVER_DESCRIPTORS; + + stdio[0].flags = UV_CREATE_PIPE | UV_READABLE_PIPE | UV_WRITABLE_PIPE; + stdio[0].data.stream = (uv_stream_t *)spawn_channel; /* bidirectional libuv pipe */ + stdio[1].flags = UV_INHERIT_FD; + stdio[1].data.fd = 1 /* UV_STDOUT_FD */; + stdio[2].flags = UV_INHERIT_FD; + stdio[2].data.fd = 2 /* UV_STDERR_FD */; + + ret = uv_spawn(loop, process, &options); /* execute the netdata binary again as the netdata user */ + if (0 != ret) { + error("uv_spawn (process: \"%s\") (user: %s) failed (%s).", exepath, user, uv_strerror(ret)); + fatal("Cannot start netdata without the spawn server."); + } + + return ret; +} + +#define CONCURRENT_SPAWNS 16 +#define SPAWN_ITERATIONS 10000 +#undef CONCURRENT_STRESS_TEST + +void spawn_init(void) +{ + struct completion completion; + int error; + + info("Initializing spawn client."); + + init_spawn_cmd_queue(); + + init_completion(&completion); + error = uv_thread_create(&thread, spawn_client, &completion); + if (error) { + error("uv_thread_create(): %s", uv_strerror(error)); + goto after_error; + } + /* wait for spawn client thread to initialize */ + wait_for_completion(&completion); + destroy_completion(&completion); + uv_thread_set_name_np(thread, "DAEMON_SPAWN"); + + if (spawn_thread_error) { + error = uv_thread_join(&thread); + if (error) { + error("uv_thread_create(): %s", uv_strerror(error)); + } + goto after_error; + } +#ifdef CONCURRENT_STRESS_TEST + signals_reset(); + signals_unblock(); + + sleep(60); + uint64_t serial[CONCURRENT_SPAWNS]; + for (int j = 0 ; j < SPAWN_ITERATIONS ; ++j) { + for (int i = 0; i < CONCURRENT_SPAWNS; ++i) { + char cmd[64]; + sprintf(cmd, "echo CONCURRENT_STRESS_TEST %d 1>&2", j * CONCURRENT_SPAWNS + i + 1); + serial[i] = spawn_enq_cmd(cmd); + info("Queued command %s for spawning.", cmd); + } + int exit_status; + time_t exec_run_timestamp; + for (int i = 0; i < CONCURRENT_SPAWNS; ++i) { + info("Started waiting for serial %llu exit status %d run timestamp %llu.", serial[i], exit_status, + exec_run_timestamp); + spawn_wait_cmd(serial[i], &exit_status, &exec_run_timestamp); + info("Finished waiting for serial %llu exit status %d run timestamp %llu.", serial[i], exit_status, + exec_run_timestamp); + } + } + exit(0); +#endif + return; + + after_error: + error("Failed to initialize spawn service. The alarms notifications will not be spawned."); +} |