5 #include <sys/syslog.h>
11 #include "dinit-log.h"
14 // Dinit logging subsystem.
16 // Note that most actual functions for logging messages are found in the header, dinit-log.h.
18 // We have two separate log "streams": one for the console/stdout, one for the syslog facility (or log
19 // file). Both have a circular buffer. Log messages are appended to the circular buffer (for a syslog
20 // stream, the messages are prepended with a syslog priority indicator). Both streams start out inactive
21 // (release = true in buffered_log_stream), which means they will buffer messages but not write them.
23 // The console log stream needs to be able to release the console, if a service is waiting to acquire it.
24 // This is accomplished by calling flush_for_release() which then completes the output of the current
25 // message (if any) and then assigns the console to a waiting service.
27 extern eventloop_t event_loop;
28 extern bool external_log_open;
30 static bool log_current_line[2]; // Whether the current line is being logged (for console, main log)
31 static bool log_format_syslog[2] = { false, true };
33 static service_set *services = nullptr; // Reference to service set
35 loglevel_t log_level[2] = { loglevel_t::INFO, loglevel_t::WARN };
36 bool console_service_status = true; // show service status messages to console?
38 dasynq::time_val release_time; // time the log was released
40 using rearm = dasynq::rearm;
43 class buffered_log_stream : public eventloop_t::fd_watcher_impl<buffered_log_stream>
48 bool partway = false; // if we are partway throught output of a log message
49 bool discarded = false; // if we have discarded a message
50 bool release = true; // if we should inhibit output and release console when possible
52 // A "special message" is not stored in the circular buffer; instead
53 // it is delivered from an external buffer not managed by BufferedLogger.
54 bool special = false; // currently outputting special message?
55 const char *special_buf; // buffer containing special message
56 int msg_index; // index into special message
58 cpbuffer<4096> log_buffer;
63 int current_index = 0; // current/next incoming message index
73 rearm fd_event(eventloop_t &loop, int fd, int flags) noexcept;
75 // Check whether the console can be released.
76 void flush_for_release();
77 bool is_release_set() { return release; }
79 // Commit a log message
82 bool was_first = current_index == 0;
83 current_index = log_buffer.get_length();
84 if (was_first && ! release) {
85 set_enabled(event_loop, true);
91 log_buffer.trim_to(current_index);
96 return log_buffer.get_free();
99 void append(const char *s, size_t len)
101 log_buffer.append(s, len);
104 // Discard buffer; call only when the stream isn't active.
108 log_buffer.trim_to(0);
111 // Mark that a message was discarded due to full buffer
112 void mark_discarded()
117 void watch_removed() noexcept override;
120 void release_console();
124 // (One for main log, one for console)
125 buffered_log_stream log_stream[2];
127 void buffered_log_stream::release_console()
130 int flags = fcntl(1, F_GETFL, 0);
131 fcntl(1, F_SETFL, flags & ~O_NONBLOCK);
132 services->pull_console_queue();
134 // release still set, we didn't immediately get the console back; record the
135 // time at which we released:
136 event_loop.get_time(release_time, clock_type::MONOTONIC);
141 void buffered_log_stream::flush_for_release()
147 // Try to flush any messages that are currently buffered. (Console is non-blocking
148 // so it will fail gracefully).
149 rearm rearm_val = fd_event(event_loop, fd, dasynq::OUT_EVENTS);
150 if (rearm_val == rearm::DISARM) {
151 // Console has already been released at this point.
152 set_enabled(event_loop, false);
154 if (rearm_val == rearm::REMOVE) {
155 deregister(event_loop);
157 // fd_event didn't want to disarm, so must be partway through a message; will
158 // release when it's finished.
161 rearm buffered_log_stream::fd_event(eventloop_t &loop, int fd, int flags) noexcept
163 if ((! partway) && (! special) && discarded) {
164 special_buf = "dinit: *** log message discarded due to full buffer ***\n";
170 if ((! partway) && special) {
171 const char * start = special_buf + msg_index;
172 const char * end = start;
173 while (*end != '\n') end++;
174 int r = bp_sys::write(fd, start, end - start + 1);
176 if (start + r > end) {
177 // All written: go on to next message in queue
184 return rearm::DISARM;
192 else if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
193 return rearm::REMOVE;
198 // Writing from the regular circular buffer
200 if (current_index == 0) {
202 return rearm::DISARM;
205 // We try to find a complete line (terminated by '\n') in the buffer, and write it
206 // out. Since it may span the circular buffer end, it may consist of two distinct spans,
207 // and so we use writev to write them atomically.
209 struct iovec logiov[2];
211 char *ptr = log_buffer.get_ptr(0);
212 int len = log_buffer.get_contiguous_length(ptr);
213 char *creptr = ptr + len; // contiguous region end
214 char *eptr = std::find(ptr, creptr, '\n');
216 bool will_complete = false; // will complete this message?
217 if (eptr != creptr) {
218 eptr++; // include '\n'
219 will_complete = true;
224 logiov[0].iov_base = ptr;
225 logiov[0].iov_len = len;
226 int iovs_to_write = 1;
228 // Do we need the second span?
229 if (! will_complete && len != log_buffer.get_length()) {
230 ptr = log_buffer.get_buf_base();
231 creptr = ptr + log_buffer.get_length() - len;
232 eptr = std::find(ptr, creptr, '\n');
233 if (eptr != creptr) {
234 eptr++; // include '\n'
235 // It should not ever be the case that we do not now have a complete message
236 will_complete = true;
238 logiov[1].iov_base = ptr;
239 logiov[1].iov_len = eptr - ptr;
240 len += logiov[1].iov_len;
244 ssize_t r = bp_sys::writev(fd, logiov, iovs_to_write);
247 bool complete = (r == len) && will_complete;
248 log_buffer.consume(len);
249 partway = ! complete;
251 current_index -= len;
252 if (current_index == 0 || release) {
253 // No more messages buffered / stop logging to console:
255 return rearm::DISARM;
259 else if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) {
260 return rearm::REMOVE;
264 // We've written something by the time we get here. We could fall through to below, but
265 // let's give other events a chance to be processed by returning now.
269 void buffered_log_stream::watch_removed() noexcept
271 if (fd > STDERR_FILENO) {
275 release = true; // prevent attempt to enable watch
277 // Here we rely on there only being two logs, console and "main"; we can check if we are the
278 // main log via identity:
279 if (&log_stream[DLOG_MAIN] == this) {
280 external_log_open = false;
286 // Initialise the logging subsystem
287 // Potentially throws std::bad_alloc or std::system_error
288 void init_log(service_set *sset, bool syslog_format)
291 log_stream[DLOG_CONS].add_watch(event_loop, STDOUT_FILENO, dasynq::OUT_EVENTS, false);
292 enable_console_log(true);
294 // The main (non-console) log won't be active yet, but we set the format here so that we
295 // buffer messages in the correct format:
296 log_format_syslog[DLOG_MAIN] = syslog_format;
299 // Close logging subsystem
302 if (log_stream[DLOG_CONS].fd != -1) log_stream[DLOG_CONS].deregister(event_loop);
303 if (log_stream[DLOG_MAIN].fd != -1) log_stream[DLOG_MAIN].deregister(event_loop);
306 // Set up the main log to output to the given file descriptor.
307 // Potentially throws std::bad_alloc or std::system_error
308 void setup_main_log(int fd)
310 log_stream[DLOG_MAIN].init(fd);
311 log_stream[DLOG_MAIN].add_watch(event_loop, fd, dasynq::OUT_EVENTS);
314 bool is_log_flushed() noexcept
316 return log_stream[DLOG_CONS].current_index == 0 &&
317 (log_stream[DLOG_MAIN].fd == -1 || log_stream[DLOG_MAIN].current_index == 0);
320 // Enable or disable console logging. If disabled, console logging will be disabled on the
321 // completion of output of the current message (if any), at which point the first service record
322 // queued in the service set will acquire the console.
323 void enable_console_log(bool enable) noexcept
325 bool log_to_console = ! log_stream[DLOG_CONS].is_release_set();
326 if (enable && ! log_to_console) {
327 // Set non-blocking IO:
328 int flags = fcntl(STDOUT_FILENO, F_GETFL, 0);
329 fcntl(STDOUT_FILENO, F_SETFL, flags | O_NONBLOCK);
331 log_stream[DLOG_CONS].init(STDOUT_FILENO);
332 log_stream[DLOG_CONS].set_enabled(event_loop, true);
334 else if (! enable && log_to_console) {
335 log_stream[DLOG_CONS].flush_for_release();
339 void discard_console_log_buffer() noexcept
341 // Only discard if more than a second has passed since we released the console.
342 dasynq::time_val current_time;
343 event_loop.get_time(current_time, clock_type::MONOTONIC);
344 if (current_time - release_time >= dasynq::time_val(1, 0)) {
345 log_stream[DLOG_CONS].discard();
349 // Variadic method to calculate the sum of string lengths:
350 static int sum_length(const char *arg) noexcept
352 return std::strlen(arg);
355 template <typename ... T> static int sum_length(const char * first, T ... args) noexcept
357 return sum_length(first) + sum_length(args...);
360 // Variadic method to append strings to a buffer:
361 static void append(buffered_log_stream &buf, const char *s)
363 buf.append(s, std::strlen(s));
366 template <typename ... T> static void append(buffered_log_stream &buf, const char *u, T ... t)
372 static int log_level_to_syslog_level(loglevel_t l)
375 case loglevel_t::DEBUG:
377 case loglevel_t::INFO:
379 case loglevel_t::WARN:
381 case loglevel_t::ERROR:
389 // Variadic method to log a sequence of strings as a single message to a particular facility:
390 template <typename ... T> static void push_to_log(int idx, T ... args) noexcept
392 if (! log_current_line[idx]) return;
393 int amount = sum_length(args...);
394 if (log_stream[idx].get_free() >= amount) {
395 append(log_stream[idx], args...);
396 log_stream[idx].commit_msg();
399 log_stream[idx].mark_discarded();
403 // Variadic method to potentially log a sequence of strings as a single message with the given log level:
404 template <typename ... T> static void do_log(loglevel_t lvl, bool to_cons, T ... args) noexcept
406 log_current_line[DLOG_CONS] = (lvl >= log_level[DLOG_CONS]) && to_cons;
407 log_current_line[DLOG_MAIN] = (lvl >= log_level[DLOG_MAIN]);
408 push_to_log(DLOG_CONS, args...);
410 if (log_current_line[DLOG_MAIN]) {
411 if (log_format_syslog[DLOG_MAIN]) {
413 snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | log_level_to_syslog_level(lvl));
414 push_to_log(DLOG_MAIN, svcbuf, args...);
417 push_to_log(DLOG_MAIN, args...);
422 template <typename ... T> static void do_log_cons(T ... args) noexcept
424 if (console_service_status) {
425 log_current_line[DLOG_CONS] = true;
426 log_current_line[DLOG_MAIN] = false;
427 push_to_log(DLOG_CONS, args...);
431 // Log to the main facility at NOTICE level
432 template <typename ... T> static void do_log_main(T ... args) noexcept
434 log_current_line[DLOG_CONS] = false;
435 log_current_line[DLOG_MAIN] = true;
437 if (log_format_syslog[DLOG_MAIN]) {
439 snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | LOG_NOTICE);
440 push_to_log(DLOG_MAIN, svcbuf, args...);
443 push_to_log(DLOG_MAIN, args...);
447 // Log a message. A newline will be appended.
448 void log(loglevel_t lvl, const char *msg) noexcept
450 do_log(lvl, true, "dinit: ", msg, "\n");
453 void log(loglevel_t lvl, bool to_cons, const char *msg) noexcept
455 do_log(lvl, to_cons, "dinit: ", msg, "\n");
458 // Log part of a message. A series of calls to do_log_part must be followed by a call to do_log_commit.
459 static void do_log_part(int idx, const char *arg) noexcept
461 if (log_current_line[idx]) {
462 int amount = sum_length(arg);
463 if (log_stream[idx].get_free() >= amount) {
464 append(log_stream[idx], arg);
467 log_stream[idx].rollback_msg();
468 log_current_line[idx] = false;
469 log_stream[idx].mark_discarded();
474 // Commit a message that was issued as a series of parts (via do_log_part).
475 static void do_log_commit(int idx) noexcept
477 if (log_current_line[idx]) {
478 log_stream[idx].commit_msg();
482 // Log a multi-part message beginning
483 void log_msg_begin(loglevel_t lvl, const char *msg) noexcept
485 log_current_line[DLOG_CONS] = lvl >= log_level[DLOG_CONS];
486 log_current_line[DLOG_MAIN] = lvl >= log_level[DLOG_MAIN];
488 // Prepend the syslog priority level string ("<N>") for the main log:
489 if (log_current_line[DLOG_MAIN]) {
490 if (log_format_syslog[DLOG_MAIN]) {
492 snprintf(svcbuf, 10, "<%d>", LOG_DAEMON | log_level_to_syslog_level(lvl));
493 do_log_part(DLOG_MAIN, svcbuf);
497 for (int i = 0; i < 2; i++) {
498 do_log_part(i, "dinit: ");
503 // Continue a multi-part log message
504 void log_msg_part(const char *msg) noexcept
506 do_log_part(DLOG_CONS, msg);
507 do_log_part(DLOG_MAIN, msg);
510 // Complete a multi-part log message
511 void log_msg_end(const char *msg) noexcept
513 for (int i = 0; i < 2; i++) {
515 do_log_part(i, "\n");
520 void log_service_started(const char *service_name) noexcept
522 do_log_cons("[ OK ] ", service_name, "\n");
523 do_log_main("dinit: service ", service_name, " started.\n");
526 void log_service_failed(const char *service_name) noexcept
528 do_log_cons("[FAILED] ", service_name, "\n");
529 do_log_main("dinit: service ", service_name, " failed to start.\n");
532 void log_service_stopped(const char *service_name) noexcept
534 do_log_cons("[STOPPD] ", service_name, "\n");
535 do_log_main("dinit: service ", service_name, " stopped.\n");