Bug Summary

File:lib/lwan-thread.c
Warning:line 709, column 9
Assigned value is garbage or undefined

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -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 -mframe-pointer=all -fmath-errno -fno-rounding-math -mconstructor-aliases -fno-plt -munwind-tables -target-cpu x86-64 -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/clang/11.1.0 -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/11.1.0/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 -stack-protector 2 -fgnuc-version=4.2.1 -analyzer-output=html -faddrsig -o /home/buildbot/lwan-worker/clang-analyze/CLANG/2021-04-27-012455-3183333-1 -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 break;
83 case EINTR4:
84 continue;
85 default:
86 return;
87 }
88 }
89
90 coro_yield(conn->coro, CONN_CORO_WANT_READ);
91 }
92
93 /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
94}
95
96__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
97 void *data)
98{
99 /* NOTE: This function should not return; coro_yield should be used
100 * instead. This ensures the storage for `strbuf` is alive when the
101 * coroutine ends and lwan_strbuf_free() is called. */
102 struct lwan_connection *conn = data;
103 struct lwan *lwan = conn->thread->lwan;
104 int fd = lwan_connection_get_fd(lwan, conn);
105 enum lwan_request_flags flags = lwan->config.request_flags;
106 struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
107 char request_buffer[DEFAULT_BUFFER_SIZE4096];
108 struct lwan_value buffer = {.value = request_buffer, .len = 0};
109 char *next_request = NULL((void*)0);
110 char *header_start[N_HEADER_START64];
111 struct lwan_proxy proxy;
112 const int error_when_n_packets = lwan_calculate_n_packets(DEFAULT_BUFFER_SIZE4096);
113
114 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
115
116 const size_t init_gen = 1; /* 1 call to coro_defer() */
117 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"
, 117, __extension__ __PRETTY_FUNCTION__); }));
118
119 while (true1) {
120 struct lwan_request_parser_helper helper = {
121 .buffer = &buffer,
122 .next_request = next_request,
123 .error_when_n_packets = error_when_n_packets,
124 .header_start = header_start,
125 };
126 struct lwan_request request = {.conn = conn,
127 .global_response_headers = &lwan->headers,
128 .fd = fd,
129 .response = {.buffer = &strbuf},
130 .flags = flags,
131 .proxy = &proxy,
132 .helper = &helper};
133
134 lwan_process_request(lwan, &request);
135
136 /* Run the deferred instructions now (except those used to initialize
137 * the coroutine), so that if the connection is gracefully closed,
138 * the storage for ``helper'' is still there. */
139 coro_deferred_run(coro, init_gen);
140
141 if (UNLIKELY(!(conn->flags & CONN_IS_KEEP_ALIVE))__builtin_expect(((!(conn->flags & CONN_IS_KEEP_ALIVE)
)), (0))) {
142 graceful_close(lwan, conn, request_buffer);
143 break;
144 }
145
146 if (next_request && *next_request) {
147 conn->flags |= CONN_CORK;
148
149 if (!(conn->flags & CONN_EVENTS_WRITE))
150 coro_yield(coro, CONN_CORO_WANT_WRITE);
151 } else {
152 conn->flags &= ~CONN_CORK;
153 coro_yield(coro, CONN_CORO_WANT_READ);
154 }
155
156 /* Ensure string buffer is reset between requests, and that the backing
157 * store isn't over 2KB. */
158 lwan_strbuf_reset_trim(&strbuf, 2048);
159
160 /* Only allow flags from config. */
161 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
162 next_request = helper.next_request;
163 }
164
165 coro_yield(coro, CONN_CORO_ABORT);
166 __builtin_unreachable();
167}
168
169static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
170conn_flags_to_epoll_events(enum lwan_connection_flags flags)
171{
172 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
173 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
174 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
175 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
176 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
177 };
178
179 return map[flags & CONN_EVENTS_MASK];
180}
181
182static void update_epoll_flags(int fd,
183 struct lwan_connection *conn,
184 int epoll_fd,
185 enum lwan_connection_coro_yield yield_result)
186{
187 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
188 [CONN_CORO_YIELD] = 0,
189
190 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
191 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
192 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
193
194 /* While the coro is suspended, we're not interested in either EPOLLIN
195 * or EPOLLOUT events. We still want to track this fd in epoll, though,
196 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
197 * are set. */
198 [CONN_CORO_SUSPEND_TIMER] = CONN_SUSPENDED_TIMER,
199 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = CONN_SUSPENDED_ASYNC_AWAIT,
200
201 /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
202 * would have to be stored and restored -- however, resuming as if the
203 * client coroutine is interested in a write event always guarantees that
204 * they'll be resumed as they're TCP sockets. There's a good chance that
205 * trying to read from a socket after resuming a coroutine will succeed,
206 * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
207 * yield with CONN_CORO_WANT_READ anyway. */
208 [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
209 };
210 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
211 [CONN_CORO_YIELD] = ~0,
212
213 [CONN_CORO_WANT_READ_WRITE] = ~0,
214 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
215 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
216
217 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
218 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
219 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
220 };
221 enum lwan_connection_flags prev_flags = conn->flags;
222
223 conn->flags |= or_mask[yield_result];
224 conn->flags &= and_mask[yield_result];
225
226 if (conn->flags == prev_flags)
227 return;
228
229 struct epoll_event event = {
230 .events = conn_flags_to_epoll_events(conn->flags),
231 .data.ptr = conn,
232 };
233
234 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0)))
235 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 235, __FUNCTION__, "epoll_ctl");
236}
237
238static void clear_async_await_flag(void *data)
239{
240 struct lwan_connection *async_fd_conn = data;
241
242 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
243}
244
245static enum lwan_connection_coro_yield
246resume_async(struct timeout_queue *tq,
247 enum lwan_connection_coro_yield yield_result,
248 int64_t from_coro,
249 struct lwan_connection *conn,
250 int epoll_fd)
251{
252 static const enum lwan_connection_flags to_connection_flags[] = {
253 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
254 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
255 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
256 };
257 int await_fd = (int)((uint64_t)from_coro >> 32);
258 enum lwan_connection_flags flags;
259 int op;
260
261 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"
, 261, __extension__ __PRETTY_FUNCTION__); }));
262 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"
, 263, __extension__ __PRETTY_FUNCTION__); }))
263 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"
, 263, __extension__ __PRETTY_FUNCTION__); }));
264
265 flags = to_connection_flags[yield_result];
266
267 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
268 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))) {
269 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1)))
270 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
271
272 op = EPOLL_CTL_MOD3;
273 } else {
274 op = EPOLL_CTL_ADD1;
275 flags |= CONN_ASYNC_AWAIT;
276 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
277 }
278
279 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
280 .data.ptr = conn};
281 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))) {
282 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
283 await_fd_conn->flags |= flags;
284 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
285 }
286
287 return CONN_CORO_ABORT;
288}
289
290static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
291 struct lwan_connection *conn,
292 int epoll_fd)
293{
294 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"
, 294, __extension__ __PRETTY_FUNCTION__); }));
295
296 int64_t from_coro = coro_resume(conn->coro);
297 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
298
299 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
300 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
301
302 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
303 return timeout_queue_expire(tq, conn);
304
305 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
306 epoll_fd, yield_result);
307}
308
309static void update_date_cache(struct lwan_thread *thread)
310{
311 time_t now = time(NULL((void*)0));
312
313 lwan_format_rfc_time(now, thread->date.date);
314 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
315 thread->date.expires);
316}
317
318static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
319 struct coro_switcher *switcher,
320 struct timeout_queue *tq)
321{
322 struct lwan_thread *t = conn->thread;
323
324 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"
, 324, __extension__ __PRETTY_FUNCTION__); }));
325 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"
, 325, __extension__ __PRETTY_FUNCTION__); }));
326 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"
, 326, __extension__ __PRETTY_FUNCTION__); }));
327 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"
, 328, __extension__ __PRETTY_FUNCTION__); }))
328 (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"
, 328, __extension__ __PRETTY_FUNCTION__); }));
329
330 *conn = (struct lwan_connection) {
331 .coro = coro_new(switcher, process_request_coro, conn),
332 .flags = CONN_EVENTS_READ,
333 .time_to_expire = tq->current_time + tq->move_to_last_bump,
334 .thread = t,
335 };
336 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
337 /* FIXME: send a "busy" response to this client? we don't have a coroutine
338 * at this point, can't use lwan_send() here */
339 lwan_status_error("Could not create coroutine, dropping connection")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 339, __FUNCTION__, "Could not create coroutine, dropping connection"
);
340
341 conn->flags = 0;
342
343 int fd = lwan_connection_get_fd(tq->lwan, conn);
344 shutdown(fd, SHUT_RDWRSHUT_RDWR);
345 close(fd);
346
347 return;
348 }
349
350 timeout_queue_insert(tq, conn);
351}
352
353static void accept_nudge(int pipe_fd,
354 struct lwan_thread *t,
355 struct lwan_connection *conns,
356 struct timeout_queue *tq,
357 struct coro_switcher *switcher,
358 int epoll_fd)
359{
360 uint64_t event;
361 int new_fd;
362
363 /* Errors are ignored here as pipe_fd serves just as a way to wake the
364 * thread from epoll_wait(). It's fine to consume the queue at this
365 * point, regardless of the error type. */
366 (void)read(pipe_fd, &event, sizeof(event));
367
368 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
369 struct lwan_connection *conn = &conns[new_fd];
370 struct epoll_event ev = {
371 .data.ptr = conn,
372 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
373 };
374
375 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1)))
376 spawn_coro(conn, switcher, tq);
377 }
378
379 timeouts_add(t->wheel, &tq->timeout, 1000);
380}
381
382static bool_Bool process_pending_timers(struct timeout_queue *tq,
383 struct lwan_thread *t,
384 int epoll_fd)
385{
386 struct timeout *timeout;
387 bool_Bool should_expire_timers = false0;
388
389 while ((timeout = timeouts_get(t->wheel))) {
390 struct lwan_request *request;
391
392 if (timeout == &tq->timeout) {
393 should_expire_timers = true1;
394 continue;
395 }
396
397 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));
398
399 update_epoll_flags(request->fd, request->conn, epoll_fd,
400 CONN_CORO_RESUME);
401 }
402
403 if (should_expire_timers) {
404 timeout_queue_expire_waiting(tq);
405
406 /* tq timeout expires every 1000ms if there are connections, so
407 * update the date cache at this point as well. */
408 update_date_cache(t);
409
410 if (!timeout_queue_empty(tq)) {
411 timeouts_add(t->wheel, &tq->timeout, 1000);
412 return true1;
413 }
414
415 timeouts_del(t->wheel, &tq->timeout);
416 }
417
418 return false0;
419}
420
421static int
422turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
423{
424 const int infinite_timeout = -1;
425 timeout_t wheel_timeout;
426 struct timespec now;
427
428 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0)))
429 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 429, __FUNCTION__, "Could not get monotonic time");
430
431 timeouts_update(t->wheel,
432 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
433
434 /* Check if there's an expired timer. */
435 wheel_timeout = timeouts_timeout(t->wheel);
436 if (wheel_timeout > 0) {
437 return (int)wheel_timeout; /* No, but will soon. Wake us up in
438 wheel_timeout ms. */
439 }
440
441 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
442 return infinite_timeout; /* None found. */
443
444 if (!process_pending_timers(tq, t, epoll_fd))
445 return infinite_timeout; /* No more timers to process. */
446
447 /* After processing pending timers, determine when to wake up. */
448 return (int)timeouts_timeout(t->wheel);
449}
450
451static void *thread_io_loop(void *data)
452{
453 struct lwan_thread *t = data;
454 int epoll_fd = t->epoll_fd;
455 const int read_pipe_fd = t->pipe_fd[0];
456 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id6
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id7 = (1024); lwan_tmp_id6 > lwan_tmp_id7 ?
lwan_tmp_id7 : lwan_tmp_id6; });
457 struct lwan *lwan = t->lwan;
458 struct epoll_event *events;
459 struct coro_switcher switcher;
460 struct timeout_queue tq;
461
462 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 463, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
463 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 463, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1);
464 lwan_set_thread_name("worker");
465
466 events = calloc((size_t)max_events, sizeof(*events));
467 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
468 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"
, 468, __FUNCTION__, "Could not allocate memory for events");
469
470 update_date_cache(t);
471
472 timeout_queue_init(&tq, lwan);
473
474 pthread_barrier_wait(&lwan->thread.barrier);
475
476 for (;;) {
477 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
478 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
479
480 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
481 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
482 break;
483 continue;
484 }
485
486 for (struct epoll_event *event = events; n_fds--; event++) {
487 struct lwan_connection *conn;
488
489 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
490 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
491 epoll_fd);
492 continue;
493 }
494
495 conn = event->data.ptr;
496
497 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))) {
498 timeout_queue_expire(&tq, conn);
499 continue;
500 }
501
502 resume_coro(&tq, conn, epoll_fd);
503 timeout_queue_move_to_last(&tq, conn);
504 }
505 }
506
507 pthread_barrier_wait(&lwan->thread.barrier);
508
509 timeout_queue_expire_all(&tq);
510 free(events);
511
512 return NULL((void*)0);
513}
514
515static void create_thread(struct lwan *l, struct lwan_thread *thread,
516 const size_t n_queue_fds)
517{
518 int ignore;
519 pthread_attr_t attr;
520
521 memset(thread, 0, sizeof(*thread));
522 thread->lwan = l;
523
524 thread->wheel = timeouts_open(&ignore);
525 if (!thread->wheel)
526 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 526, __FUNCTION__, "Could not create timer wheel");
527
528 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
529 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 529, __FUNCTION__, "epoll_create");
530
531 if (pthread_attr_init(&attr))
532 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 532, __FUNCTION__, "pthread_attr_init");
533
534 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
535 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 535, __FUNCTION__, "pthread_attr_setscope");
536
537 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
538 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 538, __FUNCTION__, "pthread_attr_setdetachstate");
539
540#if defined(HAVE_EVENTFD)
541 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
542 if (efd < 0)
543 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 543, __FUNCTION__, "eventfd");
544
545 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
546#else
547 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
548 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 548, __FUNCTION__, "pipe");
549#endif
550
551 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
552 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
553 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 553, __FUNCTION__, "epoll_ctl");
554
555 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
556 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 556, __FUNCTION__, "pthread_create");
557
558 if (pthread_attr_destroy(&attr))
559 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 559, __FUNCTION__, "pthread_attr_destroy");
560
561 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
562 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 563, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
563 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 563, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds);
564 }
565}
566
567void lwan_thread_nudge(struct lwan_thread *t)
568{
569 uint64_t event = 1;
570
571 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0)))
572 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 572, __FUNCTION__, "write");
573}
574
575void lwan_thread_add_client(struct lwan_thread *t, int fd)
576{
577 for (int i = 0; i < 10; i++) {
578 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
579
580 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
581 return;
582
583 /* Queue is full; nudge the thread to consume it. */
584 lwan_thread_nudge(t);
585 }
586
587 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 587, __FUNCTION__, "Dropping connection %d", fd);
588 /* FIXME: send "busy" response now, even without receiving request? */
589 close(fd);
590}
591
592#if defined(__linux__1) && defined(__x86_64__1)
593static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
594{
595 char path[PATH_MAX4096];
596
597 for (uint32_t i = 0; i < l->available_cpus; i++)
598 siblings[i] = 0xbebacafe;
599
600 for (unsigned int i = 0; i < l->available_cpus; i++) {
601 FILE *sib;
602 uint32_t id, sibling;
603 char separator;
604
605 snprintf(path, sizeof(path),
606 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
607 i);
608
609 sib = fopen(path, "re");
610 if (!sib) {
611 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"
, 612, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
612 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 612, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path);
613 return false0;
614 }
615
616 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
617 case 2: /* No SMT */
618 siblings[i] = id;
619 break;
620 case 3: /* SMT */
621 if (!(separator == ',' || separator == '-')) {
622 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"
, 622, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
);
623 __builtin_unreachable();
624 }
625
626 siblings[i] = sibling;
627 break;
628 default:
629 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 629, __FUNCTION__, "%s has invalid format", path);
630 __builtin_unreachable();
631 }
632
633 fclose(sib);
634 }
635
636 /* Perform a sanity check here, as some systems seem to filter out the
637 * result of sysconf() to obtain the number of configured and online
638 * CPUs but don't bother changing what's available through sysfs as far
639 * as the CPU topology information goes. It's better to fall back to a
640 * possibly non-optimal setup than just crash during startup while
641 * trying to perform an out-of-bounds array access. */
642 for (unsigned int i = 0; i < l->available_cpus; i++) {
643 if (siblings[i] == 0xbebacafe) {
644 lwan_status_warning("Could not determine sibling for CPU %d", i)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 644, __FUNCTION__, "Could not determine sibling for CPU %d"
, i);
645 return false0;
646 }
647
648 if (siblings[i] >= l->available_cpus) {
649 lwan_status_warning("CPU information topology says CPU %d exists, "lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 652, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
650 "but max available CPUs is %d (online CPUs: %d). "lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 652, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
651 "Is Lwan running in a (broken) container?",lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 652, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
652 siblings[i], l->available_cpus, l->online_cpus)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 652, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus);
653 return false0;
654 }
655 }
656
657 return true1;
658}
659
660static void
661siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
662{
663 int *seen = alloca(l->available_cpus * sizeof(int))__builtin_alloca (l->available_cpus * sizeof(int));
664 unsigned int n_schedtbl = 0;
665
666 for (uint32_t i = 0; i < l->available_cpus; i++)
667 seen[i] = -1;
668
669 for (uint32_t i = 0; i < l->available_cpus; i++) {
670 if (seen[siblings[i]] < 0) {
671 seen[siblings[i]] = (int)i;
672 } else {
673 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
674 schedtbl[n_schedtbl++] = i;
675 }
676 }
677
678 if (n_schedtbl != l->available_cpus)
679 memcpy(schedtbl, seen, l->available_cpus * sizeof(int));
680}
681
682static bool_Bool
683topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
684{
685 uint32_t *siblings = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
686
687 if (read_cpu_topology(l, siblings)) {
11
←
Assuming the condition is true
→
12
←
Taking true branch
→
688 uint32_t *affinity = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
689
690 siblings_to_schedtbl(l, siblings, affinity);
691
692 for (uint32_t i = 0; i < n_threads; i++)
13
←
Assuming 'i' is >= 'n_threads'
→
14
←
Loop condition is false. Execution continues on line 694
→
693 schedtbl[i] = affinity[i % l->available_cpus];
694 return true1;
15
←
Returning without writing to '*schedtbl'
→
695 }
696
697 for (uint32_t i = 0; i < n_threads; i++)
698 schedtbl[i] = (i / 2) % l->thread.count;
699 return false0;
700}
701
702static void
703adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
704{
705 for (uint32_t i = 0; i < l->thread.count; i++) {
19
←
Assuming 'i' is < field 'count'
→
20
←
Loop condition is true. Entering loop body
→
706 cpu_set_t set;
707
708 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0);
21
←
Loop condition is false. Exiting loop
→
709 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; }));
22
←
Assigned value is garbage or undefined
710
711 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
712 &set))
713 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"
, 713, __FUNCTION__, "Could not set affinity for thread %d", i
);
714 }
715}
716#elif defined(__x86_64__1)
717static bool_Bool
718topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
719{
720 for (uint32_t i = 0; i < n_threads; i++)
721 schedtbl[i] = (i / 2) % l->thread.count;
722 return false0;
723}
724
725static void
726adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
727{
728}
729#endif
730
731void lwan_thread_init(struct lwan *l)
732{
733 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
→
2
←
Taking false branch
→
734 (unsigned)l->thread.count + 1))
735 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 735, __FUNCTION__, "Could not create barrier");
736
737 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 737, __FUNCTION__, "Initializing threads");
738
739 l->thread.threads =
740 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
741 if (!l->thread.threads)
3
←
Assuming field 'threads' is non-null
→
4
←
Taking false branch
→
742 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"
, 742, __FUNCTION__, "Could not allocate memory for threads");
743
744 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_id8 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id9 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id8 > lwan_tmp_id9 ? lwan_tmp_id9 : lwan_tmp_id8
; })
5
←
Assuming 'lwan_tmp_id4' is <= 'lwan_tmp_id5'
→
6
←
'?' condition is false
→
745 (size_t)(2 * lwan_socket_get_backlog_size()))({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id8 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id9 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id8 > lwan_tmp_id9 ? lwan_tmp_id9 : lwan_tmp_id8
; });
746 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"
, 746, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds);
747 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 750
→
748 create_thread(l, &l->thread.threads[i], n_queue_fds);
749
750 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
751#ifdef __x86_64__1
752 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; })]
753 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })];
754
755 lwan_status_debug("%d CPUs of %d are online. "lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 757, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
756 "Reading topology to pre-schedule clients",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 757, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
757 l->online_cpus, l->available_cpus)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 757, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus);
758
759 /*
760 * Pre-schedule each file descriptor, to reduce some operations in the
761 * fast path.
762 *
763 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
764 * them can fill up a cache line. Assume siblings share cache lines and
765 * use the CPU topology to group two connections per cache line in such
766 * a way that false sharing is avoided.
767 */
768 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
769 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
770
771 bool_Bool adj_affinity = topology_to_schedtbl(l, schedtbl, n_threads);
10
←
Calling 'topology_to_schedtbl'
→
16
←
Returning from 'topology_to_schedtbl'
→
772
773 n_threads--; /* Transform count into mask for AND below */
774
775 if (adj_affinity
16.1
'adj_affinity' is true
)
17
←
Taking true branch
→
776 adjust_threads_affinity(l, schedtbl, n_threads);
18
←
Calling 'adjust_threads_affinity'
→
777
778 for (unsigned int i = 0; i < total_conns; i++)
779 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
780#else
781 for (unsigned int i = 0; i < total_conns; i++)
782 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
783#endif
784
785 pthread_barrier_wait(&l->thread.barrier);
786
787 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"
, 787, __FUNCTION__, "Worker threads created and ready to serve"
);
788}
789
790void lwan_thread_shutdown(struct lwan *l)
791{
792 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 792, __FUNCTION__, "Shutting down threads");
793
794 for (unsigned int i = 0; i < l->thread.count; i++) {
795 struct lwan_thread *t = &l->thread.threads[i];
796
797 close(t->epoll_fd);
798 lwan_thread_nudge(t);
799 }
800
801 pthread_barrier_wait(&l->thread.barrier);
802 pthread_barrier_destroy(&l->thread.barrier);
803
804 for (unsigned int i = 0; i < l->thread.count; i++) {
805 struct lwan_thread *t = &l->thread.threads[i];
806
807 close(t->pipe_fd[0]);
808#if !defined(HAVE_EVENTFD)
809 close(t->pipe_fd[1]);
810#endif
811
812 pthread_join(l->thread.threads[i].self, NULL((void*)0));
813 spsc_queue_free(&t->pending_fds);
814 timeouts_close(t->wheel);
815 }
816
817 free(l->thread.threads);
818}