Bug Summary

File:lwan-thread.c
Warning:line 657, column 25
Assigned value is garbage or undefined

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name lwan-thread.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -mthread-model posix -mframe-pointer=all -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -fno-plt -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/clang/10.0.0 -include /home/buildbot/lwan-worker/clang-analyze/build/lwan-build-config.h -D _FILE_OFFSET_BITS=64 -D _TIME_BITS=64 -I /home/buildbot/lwan-worker/clang-analyze/build/src/lib/missing -I /usr/include/luajit-2.0 -I /usr/include/valgrind -I /home/buildbot/lwan-worker/clang-analyze/build/src/lib -I /home/buildbot/lwan-worker/clang-analyze/build -internal-isystem /usr/local/include -internal-isystem /usr/lib/clang/10.0.0/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wno-unused-parameter -Wno-free-nonheap-object -std=gnu99 -fdebug-compilation-dir /home/buildbot/lwan-worker/clang-analyze/build/src/lib -ferror-limit 19 -fmessage-length 0 -stack-protector 2 -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -analyzer-output=html -faddrsig -o /home/buildbot/lwan-worker/clang-analyze/CLANG/2020-06-14-183856-564832-1 -x c /home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c
1/*
2 * lwan - simple web server
3 * Copyright (c) 2012, 2013 Leandro A. F. Pereira <leandro@hardinfo.org>
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2
8 * of the License, or any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
18 * USA.
19 */
20
21#define _GNU_SOURCE
22#include <assert.h>
23#include <errno(*__errno_location ()).h>
24#include <fcntl.h>
25#include <pthread.h>
26#include <sched.h>
27#include <stdlib.h>
28#include <string.h>
29#include <sys/epoll.h>
30#include <sys/ioctl.h>
31#include <sys/socket.h>
32#include <unistd.h>
33
34#if defined(HAVE_EVENTFD)
35#include <sys/eventfd.h>
36#endif
37
38#include "lwan-private.h"
39#include "lwan-tq.h"
40#include "list.h"
41
42static void lwan_strbuf_free_defer(void *data)
43{
44 lwan_strbuf_free((struct lwan_strbuf *)data);
45}
46
47static void graceful_close(struct lwan *l,
48 struct lwan_connection *conn,
49 char buffer[static DEFAULT_BUFFER_SIZE4096])
50{
51 int fd = lwan_connection_get_fd(l, conn);
52
53 while (TIOCOUTQ0x5411) {
54 /* This ioctl isn't probably doing what it says on the tin; the details
55 * are subtle, but it seems to do the trick to allow gracefully closing
56 * the connection in some cases with minimal system calls. */
57 int bytes_waiting;
58 int r = ioctl(fd, TIOCOUTQ0x5411, &bytes_waiting);
59
60 if (!r && !bytes_waiting) /* See note about close(2) below. */
61 return;
62 if (r < 0 && errno(*__errno_location ()) == EINTR4)
63 continue;
64
65 break;
66 }
67
68 if (UNLIKELY(shutdown(fd, SHUT_WR) < 0)__builtin_expect(((shutdown(fd, SHUT_WR) < 0)), (0))) {
69 if (UNLIKELY(errno == ENOTCONN)__builtin_expect((((*__errno_location ()) == 107)), (0)))
70 return;
71 }
72
73 for (int tries = 0; tries < 20; tries++) {
74 ssize_t r = read(fd, buffer, DEFAULT_BUFFER_SIZE4096);
75
76 if (!r)
77 break;
78
79 if (r < 0) {
80 switch (errno(*__errno_location ())) {
81 case EAGAIN11:
82 coro_yield(conn->coro, CONN_CORO_WANT_READ);
83 /* Fallthrough */
84 case EINTR4:
85 continue;
86 default:
87 return;
88 }
89 }
90
91 coro_yield(conn->coro, CONN_CORO_YIELD);
92 }
93
94 /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
95}
96
97__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
98 void *data)
99{
100 /* NOTE: This function should not return; coro_yield should be used
101 * instead. This ensures the storage for `strbuf` is alive when the
102 * coroutine ends and lwan_strbuf_free() is called. */
103 struct lwan_connection *conn = data;
104 struct lwan *lwan = conn->thread->lwan;
105 int fd = lwan_connection_get_fd(lwan, conn);
106 enum lwan_request_flags flags = lwan->config.request_flags;
107 struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
108 char request_buffer[DEFAULT_BUFFER_SIZE4096];
109 struct lwan_value buffer = {.value = request_buffer, .len = 0};
110 char *next_request = NULL((void*)0);
111 struct lwan_proxy proxy;
112
113 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
114
115 const size_t init_gen = 1; /* 1 call to coro_defer() */
116 assert(init_gen == coro_deferred_get_generation(coro))((void) sizeof ((init_gen == coro_deferred_get_generation(coro
)) ? 1 : 0), __extension__ ({ if (init_gen == coro_deferred_get_generation
(coro)) ; else __assert_fail ("init_gen == coro_deferred_get_generation(coro)"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 116, __extension__ __PRETTY_FUNCTION__); }));
117
118 while (true1) {
119 struct lwan_request request = {.conn = conn,
120 .fd = fd,
121 .response = {.buffer = &strbuf},
122 .flags = flags,
123 .proxy = &proxy};
124
125 next_request =
126 lwan_process_request(lwan, &request, &buffer, next_request);
127
128 if (coro_deferred_get_generation(coro) > ((2 * LWAN_ARRAY_INCREMENT16) / 3)) {
129 /* Batch execution of coro_defers() up to 2/3 LWAN_ARRAY_INCREMENT times,
130 * to avoid moving deferred array to heap in most cases. (This is to give
131 * some slack to the next request being processed by this coro.) */
132 coro_deferred_run(coro, init_gen);
133 }
134
135 if (LIKELY(conn->flags & CONN_IS_KEEP_ALIVE)__builtin_expect((!!(conn->flags & CONN_IS_KEEP_ALIVE)
), (1))) {
136 if (next_request && *next_request) {
137 conn->flags |= CONN_CORK;
138 coro_yield(coro, CONN_CORO_WANT_WRITE);
139 } else {
140 conn->flags &= ~CONN_CORK;
141 coro_yield(coro, CONN_CORO_WANT_READ);
142 }
143 } else {
144 graceful_close(lwan, conn, request_buffer);
145 break;
146 }
147
148 lwan_strbuf_reset(&strbuf);
149
150 /* Only allow flags from config. */
151 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
152 }
153
154 coro_yield(coro, CONN_CORO_ABORT);
155 __builtin_unreachable();
156}
157
158#undef REQUEST_FLAG
159
160static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
161conn_flags_to_epoll_events(enum lwan_connection_flags flags)
162{
163 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
164 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
165 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
166 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
167 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
168 };
169
170 return map[flags & CONN_EVENTS_MASK];
171}
172
173static void update_epoll_flags(int fd,
174 struct lwan_connection *conn,
175 int epoll_fd,
176 enum lwan_connection_coro_yield yield_result)
177{
178 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
179 [CONN_CORO_YIELD] = 0,
180
181 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
182 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
183 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
184
185 /* While the coro is suspended, we're not interested in either EPOLLIN
186 * or EPOLLOUT events. We still want to track this fd in epoll, though,
187 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
188 * are set. */
189 [CONN_CORO_SUSPEND_TIMER] = CONN_SUSPENDED_TIMER,
190 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = CONN_SUSPENDED_ASYNC_AWAIT,
191
192 /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
193 * would have to be stored and restored -- however, resuming as if the
194 * client coroutine is interested in a write event always guarantees that
195 * they'll be resumed as they're TCP sockets. There's a good chance that
196 * trying to read from a socket after resuming a coroutine will succeed,
197 * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
198 * yield with CONN_CORO_WANT_READ anyway. */
199 [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
200 };
201 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
202 [CONN_CORO_YIELD] = ~0,
203
204 [CONN_CORO_WANT_READ_WRITE] = ~0,
205 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
206 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
207
208 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
209 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
210 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
211 };
212 enum lwan_connection_flags prev_flags = conn->flags;
213
214 conn->flags |= or_mask[yield_result];
215 conn->flags &= and_mask[yield_result];
216
217 if (conn->flags == prev_flags)
218 return;
219
220 struct epoll_event event = {
221 .events = conn_flags_to_epoll_events(conn->flags),
222 .data.ptr = conn,
223 };
224
225 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0)))
226 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 226, __FUNCTION__, "epoll_ctl");
227}
228
229static void clear_async_await_flag(void *data)
230{
231 struct lwan_connection *async_fd_conn = data;
232
233 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
234}
235
236static enum lwan_connection_coro_yield
237resume_async(struct timeout_queue *tq,
238 enum lwan_connection_coro_yield yield_result,
239 int64_t from_coro,
240 struct lwan_connection *conn,
241 int epoll_fd)
242{
243 static const enum lwan_connection_flags to_connection_flags[] = {
244 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
245 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
246 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
247 };
248 int await_fd = (int)((uint64_t)from_coro >> 32);
249 enum lwan_connection_flags flags;
250 int op;
251
252 assert(await_fd >= 0)((void) sizeof ((await_fd >= 0) ? 1 : 0), __extension__ ({
if (await_fd >= 0) ; else __assert_fail ("await_fd >= 0"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 252, __extension__ __PRETTY_FUNCTION__); }));
253 assert(yield_result >= CONN_CORO_ASYNC_AWAIT_READ &&((void) sizeof ((yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE
) ? 1 : 0), __extension__ ({ if (yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE
) ; else __assert_fail ("yield_result >= CONN_CORO_ASYNC_AWAIT_READ && yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 254, __extension__ __PRETTY_FUNCTION__); }))
254 yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE)((void) sizeof ((yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE
) ? 1 : 0), __extension__ ({ if (yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE
) ; else __assert_fail ("yield_result >= CONN_CORO_ASYNC_AWAIT_READ && yield_result <= CONN_CORO_ASYNC_AWAIT_READ_WRITE"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 254, __extension__ __PRETTY_FUNCTION__); }));
255
256 flags = to_connection_flags[yield_result];
257
258 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
259 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))) {
260 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1)))
261 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
262
263 op = EPOLL_CTL_MOD3;
264 } else {
265 op = EPOLL_CTL_ADD1;
266 flags |= CONN_ASYNC_AWAIT;
267 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
268 }
269
270 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
271 .data.ptr = conn};
272 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))) {
273 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
274 await_fd_conn->flags |= flags;
275 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
276 }
277
278 return CONN_CORO_ABORT;
279}
280
281static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
282 struct lwan_connection *conn,
283 int epoll_fd)
284{
285 assert(conn->coro)((void) sizeof ((conn->coro) ? 1 : 0), __extension__ ({ if
(conn->coro) ; else __assert_fail ("conn->coro", "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 285, __extension__ __PRETTY_FUNCTION__); }));
286
287 int64_t from_coro = coro_resume(conn->coro);
288 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
289
290 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
291 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
292
293 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
294 return timeout_queue_expire(tq, conn);
295
296 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
297 epoll_fd, yield_result);
298}
299
300static void update_date_cache(struct lwan_thread *thread)
301{
302 time_t now = time(NULL((void*)0));
303
304 lwan_format_rfc_time(now, thread->date.date);
305 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
306 thread->date.expires);
307}
308
309static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
310 struct coro_switcher *switcher,
311 struct timeout_queue *tq)
312{
313 struct lwan_thread *t = conn->thread;
314
315 assert(!conn->coro)((void) sizeof ((!conn->coro) ? 1 : 0), __extension__ ({ if
(!conn->coro) ; else __assert_fail ("!conn->coro", "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 315, __extension__ __PRETTY_FUNCTION__); }));
316 assert(t)((void) sizeof ((t) ? 1 : 0), __extension__ ({ if (t) ; else __assert_fail
("t", "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 316, __extension__ __PRETTY_FUNCTION__); }));
317 assert((uintptr_t)t >= (uintptr_t)tq->lwan->thread.threads)((void) sizeof (((uintptr_t)t >= (uintptr_t)tq->lwan->
thread.threads) ? 1 : 0), __extension__ ({ if ((uintptr_t)t >=
(uintptr_t)tq->lwan->thread.threads) ; else __assert_fail
("(uintptr_t)t >= (uintptr_t)tq->lwan->thread.threads"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 317, __extension__ __PRETTY_FUNCTION__); }));
318 assert((uintptr_t)t <((void) sizeof (((uintptr_t)t < (uintptr_t)(tq->lwan->
thread.threads + tq->lwan->thread.count)) ? 1 : 0), __extension__
({ if ((uintptr_t)t < (uintptr_t)(tq->lwan->thread.
threads + tq->lwan->thread.count)) ; else __assert_fail
("(uintptr_t)t < (uintptr_t)(tq->lwan->thread.threads + tq->lwan->thread.count)"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 319, __extension__ __PRETTY_FUNCTION__); }))
319 (uintptr_t)(tq->lwan->thread.threads + tq->lwan->thread.count))((void) sizeof (((uintptr_t)t < (uintptr_t)(tq->lwan->
thread.threads + tq->lwan->thread.count)) ? 1 : 0), __extension__
({ if ((uintptr_t)t < (uintptr_t)(tq->lwan->thread.
threads + tq->lwan->thread.count)) ; else __assert_fail
("(uintptr_t)t < (uintptr_t)(tq->lwan->thread.threads + tq->lwan->thread.count)"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 319, __extension__ __PRETTY_FUNCTION__); }));
320
321 *conn = (struct lwan_connection) {
322 .coro = coro_new(switcher, process_request_coro, conn),
323 .flags = CONN_EVENTS_READ,
324 .time_to_expire = tq->current_time + tq->move_to_last_bump,
325 .thread = t,
326 };
327 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
328 conn->flags = 0;
329 lwan_status_error("Could not create coroutine")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 329, __FUNCTION__, "Could not create coroutine");
330 return;
331 }
332
333 timeout_queue_insert(tq, conn);
334}
335
336static void accept_nudge(int pipe_fd,
337 struct lwan_thread *t,
338 struct lwan_connection *conns,
339 struct timeout_queue *tq,
340 struct coro_switcher *switcher,
341 int epoll_fd)
342{
343 uint64_t event;
344 int new_fd;
345
346 /* Errors are ignored here as pipe_fd serves just as a way to wake the
347 * thread from epoll_wait(). It's fine to consume the queue at this
348 * point, regardless of the error type. */
349 (void)read(pipe_fd, &event, sizeof(event));
350
351 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
352 struct lwan_connection *conn = &conns[new_fd];
353 struct epoll_event ev = {
354 .data.ptr = conn,
355 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
356 };
357
358 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1)))
359 spawn_coro(conn, switcher, tq);
360 }
361
362 timeouts_add(t->wheel, &tq->timeout, 1000);
363}
364
365static bool_Bool process_pending_timers(struct timeout_queue *tq,
366 struct lwan_thread *t,
367 int epoll_fd)
368{
369 struct timeout *timeout;
370 bool_Bool should_expire_timers = false0;
371
372 while ((timeout = timeouts_get(t->wheel))) {
373 struct lwan_request *request;
374
375 if (timeout == &tq->timeout) {
376 should_expire_timers = true1;
377 continue;
378 }
379
380 request = container_of(timeout, struct lwan_request, timeout)((struct lwan_request *) ((char *)(timeout) - __builtin_offsetof
(struct lwan_request, timeout)) + ((typeof(*(timeout)) *)0 !=
(typeof(((struct lwan_request *)0)->timeout) *)0));
381
382 update_epoll_flags(request->fd, request->conn, epoll_fd,
383 CONN_CORO_RESUME);
384 }
385
386 if (should_expire_timers) {
387 timeout_queue_expire_waiting(tq);
388
389 /* tq timeout expires every 1000ms if there are connections, so
390 * update the date cache at this point as well. */
391 update_date_cache(t);
392
393 if (!timeout_queue_empty(tq)) {
394 timeouts_add(t->wheel, &tq->timeout, 1000);
395 return true1;
396 }
397
398 timeouts_del(t->wheel, &tq->timeout);
399 }
400
401 return false0;
402}
403
404static int
405turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
406{
407 timeout_t wheel_timeout;
408 struct timespec now;
409
410 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0)))
411 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 411, __FUNCTION__, "Could not get monotonic time");
412
413 timeouts_update(t->wheel,
414 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
415
416 wheel_timeout = timeouts_timeout(t->wheel);
417 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
418 goto infinite_timeout;
419
420 if (wheel_timeout == 0) {
421 if (!process_pending_timers(tq, t, epoll_fd))
422 goto infinite_timeout;
423
424 wheel_timeout = timeouts_timeout(t->wheel);
425 if (wheel_timeout == 0)
426 goto infinite_timeout;
427 }
428
429 return (int)wheel_timeout;
430
431infinite_timeout:
432 return -1;
433}
434
435static void *thread_io_loop(void *data)
436{
437 struct lwan_thread *t = data;
438 int epoll_fd = t->epoll_fd;
439 const int read_pipe_fd = t->pipe_fd[0];
440 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id4
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id5 = (1024); lwan_tmp_id4 > lwan_tmp_id5 ?
lwan_tmp_id5 : lwan_tmp_id4; });
441 struct lwan *lwan = t->lwan;
442 struct epoll_event *events;
443 struct coro_switcher switcher;
444 struct timeout_queue tq;
445
446 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 447, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
447 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 447, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1);
448 lwan_set_thread_name("worker");
449
450 events = calloc((size_t)max_events, sizeof(*events));
451 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
452 lwan_status_critical("Could not allocate memory for events")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 452, __FUNCTION__, "Could not allocate memory for events");
453
454 update_date_cache(t);
455
456 timeout_queue_init(&tq, lwan);
457
458 pthread_barrier_wait(&lwan->thread.barrier);
459
460 for (;;) {
461 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
462 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
463
464 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
465 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
466 break;
467 continue;
468 }
469
470 for (struct epoll_event *event = events; n_fds--; event++) {
471 struct lwan_connection *conn;
472
473 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
474 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
475 epoll_fd);
476 continue;
477 }
478
479 conn = event->data.ptr;
480
481 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))) {
482 timeout_queue_expire(&tq, conn);
483 continue;
484 }
485
486 resume_coro(&tq, conn, epoll_fd);
487 timeout_queue_move_to_last(&tq, conn);
488 }
489 }
490
491 pthread_barrier_wait(&lwan->thread.barrier);
492
493 timeout_queue_expire_all(&tq);
494 free(events);
495
496 return NULL((void*)0);
497}
498
499static void create_thread(struct lwan *l, struct lwan_thread *thread,
500 const size_t n_queue_fds)
501{
502 int ignore;
503 pthread_attr_t attr;
504
505 memset(thread, 0, sizeof(*thread));
506 thread->lwan = l;
507
508 thread->wheel = timeouts_open(&ignore);
509 if (!thread->wheel)
510 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 510, __FUNCTION__, "Could not create timer wheel");
511
512 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
513 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 513, __FUNCTION__, "epoll_create");
514
515 if (pthread_attr_init(&attr))
516 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 516, __FUNCTION__, "pthread_attr_init");
517
518 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
519 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 519, __FUNCTION__, "pthread_attr_setscope");
520
521 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
522 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 522, __FUNCTION__, "pthread_attr_setdetachstate");
523
524#if defined(HAVE_EVENTFD)
525 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
526 if (efd < 0)
527 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 527, __FUNCTION__, "eventfd");
528
529 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
530#else
531 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
532 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 532, __FUNCTION__, "pipe");
533#endif
534
535 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
536 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
537 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 537, __FUNCTION__, "epoll_ctl");
538
539 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
540 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 540, __FUNCTION__, "pthread_create");
541
542 if (pthread_attr_destroy(&attr))
543 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 543, __FUNCTION__, "pthread_attr_destroy");
544
545 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
546 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 547, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
547 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 547, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds);
548 }
549}
550
551void lwan_thread_nudge(struct lwan_thread *t)
552{
553 uint64_t event = 1;
554
555 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0)))
556 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 556, __FUNCTION__, "write");
557}
558
559void lwan_thread_add_client(struct lwan_thread *t, int fd)
560{
561 for (int i = 0; i < 10; i++) {
562 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
563
564 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
565 return;
566
567 /* Queue is full; nudge the thread to consume it. */
568 lwan_thread_nudge(t);
569 }
570
571 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 571, __FUNCTION__, "Dropping connection %d", fd);
572 /* FIXME: send "busy" response now, even without receiving request? */
573 close(fd);
574}
575
576#if defined(__linux__1) && defined(__x86_64__1)
577static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
578{
579 char path[PATH_MAX4096];
580
581 for (unsigned int i = 0; i < l->n_cpus; i++) {
582 FILE *sib;
583 uint32_t id, sibling;
584 char separator;
585
586 snprintf(path, sizeof(path),
587 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
588 i);
589
590 sib = fopen(path, "re");
591 if (!sib) {
592 lwan_status_warning("Could not open `%s` to determine CPU topology",lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 593, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
593 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 593, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path);
594 return false0;
595 }
596
597 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
598 case 2: /* No SMT */
599 siblings[i] = id;
600 break;
601 case 3: /* SMT */
602 if (!(separator == ',' || separator == '-')) {
603 lwan_status_critical("Expecting either ',' or '-' for sibling separator")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 603, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
);
604 __builtin_unreachable();
605 }
606
607 siblings[i] = sibling;
608 break;
609 default:
610 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 610, __FUNCTION__, "%s has invalid format", path);
611 __builtin_unreachable();
612 }
613
614
615 fclose(sib);
616 }
617
618 return true1;
619}
620
621static void
622siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
623{
624 int *seen = alloca(l->n_cpus * sizeof(int))__builtin_alloca (l->n_cpus * sizeof(int));
625 int n_schedtbl = 0;
626
627 for (uint32_t i = 0; i < l->n_cpus; i++)
14
←
Assuming 'i' is < field 'n_cpus'
→
15
←
Loop condition is true. Entering loop body
→
16
←
Assuming 'i' is < field 'n_cpus'
→
17
←
Loop condition is true. Entering loop body
→
18
←
Assuming 'i' is < field 'n_cpus'
→
19
←
Loop condition is true. Entering loop body
→
20
←
Assuming 'i' is >= field 'n_cpus'
→
21
←
Loop condition is false. Execution continues on line 630
→
628 seen[i] = -1;
629
630 for (uint32_t i = 0; i < l->n_cpus; i++) {
22
←
Loop condition is true. Entering loop body
→
25
←
Loop condition is true. Entering loop body
→
28
←
Loop condition is true. Entering loop body
→
31
←
Loop condition is false. Execution continues on line 639
→
631 if (seen[siblings[i]] < 0) {
23
←
Assuming the condition is false
→
24
←
Taking false branch
→
26
←
Assuming the condition is true
→
27
←
Taking true branch
→
29
←
Assuming the condition is true
→
30
←
Taking true branch
→
632 seen[siblings[i]] = (int)i;
633 } else {
634 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
635 schedtbl[n_schedtbl++] = i;
636 }
637 }
638
639 if (!n_schedtbl
31.1
'n_schedtbl' is 2
)
32
←
Taking false branch
→
640 memcpy(schedtbl, seen, l->n_cpus * sizeof(int));
641}
642
643static void
644topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
645{
646 uint32_t *siblings = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
647
648 if (!read_cpu_topology(l, siblings)) {
11
←
Assuming the condition is false
→
12
←
Taking false branch
→
649 for (uint32_t i = 0; i < n_threads; i++)
650 schedtbl[i] = (i / 2) % l->thread.count;
651 } else {
652 uint32_t *affinity = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
653
654 siblings_to_schedtbl(l, siblings, affinity);
13
←
Calling 'siblings_to_schedtbl'
→
33
←
Returning from 'siblings_to_schedtbl'
→
655
656 for (uint32_t i = 0; i < n_threads; i++)
34
←
Assuming 'i' is < 'n_threads'
→
35
←
Loop condition is true. Entering loop body
→
36
←
Assuming 'i' is < 'n_threads'
→
37
←
Loop condition is true. Entering loop body
→
38
←
Assuming 'i' is < 'n_threads'
→
39
←
Loop condition is true. Entering loop body
→
657 schedtbl[i] = affinity[i % l->n_cpus];
40
←
Assigned value is garbage or undefined
658 }
659}
660
661static void
662adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
663{
664 for (uint32_t i = 0; i < l->thread.count; i++) {
665 cpu_set_t set;
666
667 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0);
668 CPU_SET(schedtbl[i & mask], &set)(__extension__ ({ size_t __cpu = (schedtbl[i & mask]); __cpu
/ 8 < (sizeof (cpu_set_t)) ? (((__cpu_mask *) ((&set)
->__bits))[((__cpu) / (8 * sizeof (__cpu_mask)))] |= ((__cpu_mask
) 1 << ((__cpu) % (8 * sizeof (__cpu_mask))))) : 0; }));
669
670 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
671 &set))
672 lwan_status_warning("Could not set affinity for thread %d", i)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 672, __FUNCTION__, "Could not set affinity for thread %d", i
);
673 }
674}
675#elif defined(__x86_64__1)
676static void
677topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
678{
679 for (uint32_t i = 0; i < n_threads; i++)
680 schedtbl[i] = (i / 2) % l->thread.count;
681}
682
683static void
684adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
685{
686}
687#endif
688
689void lwan_thread_init(struct lwan *l)
690{
691 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
→
2
←
Taking false branch
→
692 (unsigned)l->thread.count + 1))
693 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 693, __FUNCTION__, "Could not create barrier");
694
695 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 695, __FUNCTION__, "Initializing threads");
696
697 l->thread.threads =
698 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
699 if (!l->thread.threads)
3
←
Assuming field 'threads' is non-null
→
4
←
Taking false branch
→
700 lwan_status_critical("Could not allocate memory for threads")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 700, __FUNCTION__, "Could not allocate memory for threads");
701
702 const size_t n_queue_fds = LWAN_MIN(l->thread.max_fd / l->thread.count,({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id6 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id7 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id6 > lwan_tmp_id7 ? lwan_tmp_id7 : lwan_tmp_id6
; })
5
←
Assuming 'lwan_tmp_id2' is <= 'lwan_tmp_id3'
→
6
←
'?' condition is false
→
703 (size_t)(2 * lwan_socket_get_backlog_size()))({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id6 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id7 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id6 > lwan_tmp_id7 ? lwan_tmp_id7 : lwan_tmp_id6
; });
704 lwan_status_debug("Pending client file descriptor queue has %zu items", n_queue_fds)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 704, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds);
705 for (unsigned int i = 0; i
6.1
'i' is < field 'count'
 < l->thread.count; i++)
7
←
Loop condition is true. Entering loop body
→
8
←
Assuming 'i' is >= field 'count'
→
9
←
Loop condition is false. Execution continues on line 708
→
706 create_thread(l, &l->thread.threads[i], n_queue_fds);
707
708 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
709#ifdef __x86_64__1
710 static_assert(sizeof(struct lwan_connection) == 32,extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })]
711 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })];
712 /*
713 * Pre-schedule each file descriptor, to reduce some operations in the
714 * fast path.
715 *
716 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
717 * them can fill up a cache line. Assume siblings share cache lines and
718 * use the CPU topology to group two connections per cache line in such
719 * a way that false sharing is avoided.
720 */
721 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
722 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
723
724 topology_to_schedtbl(l, schedtbl, n_threads);
10
←
Calling 'topology_to_schedtbl'
→
725
726 n_threads--; /* Transform count into mask for AND below */
727 adjust_threads_affinity(l, schedtbl, n_threads);
728 for (unsigned int i = 0; i < total_conns; i++)
729 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
730#else
731 for (unsigned int i = 0; i < total_conns; i++)
732 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
733#endif
734
735 pthread_barrier_wait(&l->thread.barrier);
736
737 lwan_status_debug("Worker threads created and ready to serve")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 737, __FUNCTION__, "Worker threads created and ready to serve"
);
738}
739
740void lwan_thread_shutdown(struct lwan *l)
741{
742 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 742, __FUNCTION__, "Shutting down threads");
743
744 for (unsigned int i = 0; i < l->thread.count; i++) {
745 struct lwan_thread *t = &l->thread.threads[i];
746
747 close(t->epoll_fd);
748 lwan_thread_nudge(t);
749 }
750
751 pthread_barrier_wait(&l->thread.barrier);
752 pthread_barrier_destroy(&l->thread.barrier);
753
754 for (unsigned int i = 0; i < l->thread.count; i++) {
755 struct lwan_thread *t = &l->thread.threads[i];
756
757 close(t->pipe_fd[0]);
758#if !defined(HAVE_EVENTFD)
759 close(t->pipe_fd[1]);
760#endif
761
762 pthread_join(l->thread.threads[i].self, NULL((void*)0));
763 spsc_queue_free(&t->pending_fds);
764 timeouts_close(t->wheel);
765 }
766
767 free(l->thread.threads);
768}