Bug Summary

File:lwan-thread.c
Warning:line 734, column 31
Array subscript is 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/2020-07-11-180817-1285247-1 -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 char *header_start[N_HEADER_START64];
112 struct lwan_proxy proxy;
113 const int error_when_n_packets = lwan_calculate_n_packets(DEFAULT_BUFFER_SIZE4096);
114
115 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
116
117 const size_t init_gen = 1; /* 1 call to coro_defer() */
118 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"
, 118, __extension__ __PRETTY_FUNCTION__); }));
119
120 while (true1) {
121 struct lwan_request_parser_helper helper = {
122 .buffer = &buffer,
123 .next_request = next_request,
124 .error_when_n_packets = error_when_n_packets,
125 .header_start = header_start,
126 };
127 struct lwan_request request = {
128 .conn = conn,
129 .global_response_headers = &lwan->headers,
130 .fd = fd,
131 .response = {.buffer = &strbuf},
132 .flags = flags,
133 .proxy = &proxy,
134 .helper = &helper,
135 };
136
137 lwan_process_request(lwan, &request, next_request);
138
139
140 if (LIKELY(conn->flags & CONN_IS_KEEP_ALIVE)__builtin_expect((!!(conn->flags & CONN_IS_KEEP_ALIVE)
), (1))) {
141 if (next_request && *next_request) {
142 conn->flags |= CONN_CORK;
143 coro_yield(coro, CONN_CORO_WANT_WRITE);
144 } else {
145 conn->flags &= ~CONN_CORK;
146 coro_yield(coro, CONN_CORO_WANT_READ);
147 }
148 } else {
149 graceful_close(lwan, conn, request_buffer);
150 break;
151 }
152
153 lwan_strbuf_reset(&strbuf);
154 coro_deferred_run(coro, init_gen);
155
156 /* Only allow flags from config. */
157 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
158 next_request = helper.next_request;
159 }
160
161 coro_yield(coro, CONN_CORO_ABORT);
162 __builtin_unreachable();
163}
164
165static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
166conn_flags_to_epoll_events(enum lwan_connection_flags flags)
167{
168 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
169 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
170 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
171 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
172 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
173 };
174
175 return map[flags & CONN_EVENTS_MASK];
176}
177
178static void update_epoll_flags(int fd,
179 struct lwan_connection *conn,
180 int epoll_fd,
181 enum lwan_connection_coro_yield yield_result)
182{
183 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
184 [CONN_CORO_YIELD] = 0,
185
186 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
187 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
188 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
189
190 /* While the coro is suspended, we're not interested in either EPOLLIN
191 * or EPOLLOUT events. We still want to track this fd in epoll, though,
192 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
193 * are set. */
194 [CONN_CORO_SUSPEND_TIMER] = CONN_SUSPENDED_TIMER,
195 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = CONN_SUSPENDED_ASYNC_AWAIT,
196
197 /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
198 * would have to be stored and restored -- however, resuming as if the
199 * client coroutine is interested in a write event always guarantees that
200 * they'll be resumed as they're TCP sockets. There's a good chance that
201 * trying to read from a socket after resuming a coroutine will succeed,
202 * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
203 * yield with CONN_CORO_WANT_READ anyway. */
204 [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
205 };
206 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
207 [CONN_CORO_YIELD] = ~0,
208
209 [CONN_CORO_WANT_READ_WRITE] = ~0,
210 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
211 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
212
213 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
214 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
215 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
216 };
217 enum lwan_connection_flags prev_flags = conn->flags;
218
219 conn->flags |= or_mask[yield_result];
220 conn->flags &= and_mask[yield_result];
221
222 if (conn->flags == prev_flags)
223 return;
224
225 struct epoll_event event = {
226 .events = conn_flags_to_epoll_events(conn->flags),
227 .data.ptr = conn,
228 };
229
230 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0)))
231 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 231, __FUNCTION__, "epoll_ctl");
232}
233
234static void clear_async_await_flag(void *data)
235{
236 struct lwan_connection *async_fd_conn = data;
237
238 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
239}
240
241static enum lwan_connection_coro_yield
242resume_async(struct timeout_queue *tq,
243 enum lwan_connection_coro_yield yield_result,
244 int64_t from_coro,
245 struct lwan_connection *conn,
246 int epoll_fd)
247{
248 static const enum lwan_connection_flags to_connection_flags[] = {
249 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
250 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
251 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
252 };
253 int await_fd = (int)((uint64_t)from_coro >> 32);
254 enum lwan_connection_flags flags;
255 int op;
256
257 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"
, 257, __extension__ __PRETTY_FUNCTION__); }));
258 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"
, 259, __extension__ __PRETTY_FUNCTION__); }))
259 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"
, 259, __extension__ __PRETTY_FUNCTION__); }));
260
261 flags = to_connection_flags[yield_result];
262
263 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
264 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))) {
265 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1)))
266 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
267
268 op = EPOLL_CTL_MOD3;
269 } else {
270 op = EPOLL_CTL_ADD1;
271 flags |= CONN_ASYNC_AWAIT;
272 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
273 }
274
275 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
276 .data.ptr = conn};
277 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))) {
278 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
279 await_fd_conn->flags |= flags;
280 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
281 }
282
283 return CONN_CORO_ABORT;
284}
285
286static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
287 struct lwan_connection *conn,
288 int epoll_fd)
289{
290 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"
, 290, __extension__ __PRETTY_FUNCTION__); }));
291
292 int64_t from_coro = coro_resume(conn->coro);
293 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
294
295 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
296 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
297
298 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
299 return timeout_queue_expire(tq, conn);
300
301 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
302 epoll_fd, yield_result);
303}
304
305static void update_date_cache(struct lwan_thread *thread)
306{
307 time_t now = time(NULL((void*)0));
308
309 lwan_format_rfc_time(now, thread->date.date);
310 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
311 thread->date.expires);
312}
313
314static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
315 struct coro_switcher *switcher,
316 struct timeout_queue *tq)
317{
318 struct lwan_thread *t = conn->thread;
319
320 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"
, 320, __extension__ __PRETTY_FUNCTION__); }));
321 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"
, 321, __extension__ __PRETTY_FUNCTION__); }));
322 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"
, 322, __extension__ __PRETTY_FUNCTION__); }));
323 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"
, 324, __extension__ __PRETTY_FUNCTION__); }))
324 (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"
, 324, __extension__ __PRETTY_FUNCTION__); }));
325
326 *conn = (struct lwan_connection) {
327 .coro = coro_new(switcher, process_request_coro, conn),
328 .flags = CONN_EVENTS_READ,
329 .time_to_expire = tq->current_time + tq->move_to_last_bump,
330 .thread = t,
331 };
332 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
333 conn->flags = 0;
334 lwan_status_error("Could not create coroutine")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 334, __FUNCTION__, "Could not create coroutine");
335 return;
336 }
337
338 timeout_queue_insert(tq, conn);
339}
340
341static void accept_nudge(int pipe_fd,
342 struct lwan_thread *t,
343 struct lwan_connection *conns,
344 struct timeout_queue *tq,
345 struct coro_switcher *switcher,
346 int epoll_fd)
347{
348 uint64_t event;
349 int new_fd;
350
351 /* Errors are ignored here as pipe_fd serves just as a way to wake the
352 * thread from epoll_wait(). It's fine to consume the queue at this
353 * point, regardless of the error type. */
354 (void)read(pipe_fd, &event, sizeof(event));
355
356 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
357 struct lwan_connection *conn = &conns[new_fd];
358 struct epoll_event ev = {
359 .data.ptr = conn,
360 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
361 };
362
363 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1)))
364 spawn_coro(conn, switcher, tq);
365 }
366
367 timeouts_add(t->wheel, &tq->timeout, 1000);
368}
369
370static bool_Bool process_pending_timers(struct timeout_queue *tq,
371 struct lwan_thread *t,
372 int epoll_fd)
373{
374 struct timeout *timeout;
375 bool_Bool should_expire_timers = false0;
376
377 while ((timeout = timeouts_get(t->wheel))) {
378 struct lwan_request *request;
379
380 if (timeout == &tq->timeout) {
381 should_expire_timers = true1;
382 continue;
383 }
384
385 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));
386
387 update_epoll_flags(request->fd, request->conn, epoll_fd,
388 CONN_CORO_RESUME);
389 }
390
391 if (should_expire_timers) {
392 timeout_queue_expire_waiting(tq);
393
394 /* tq timeout expires every 1000ms if there are connections, so
395 * update the date cache at this point as well. */
396 update_date_cache(t);
397
398 if (!timeout_queue_empty(tq)) {
399 timeouts_add(t->wheel, &tq->timeout, 1000);
400 return true1;
401 }
402
403 timeouts_del(t->wheel, &tq->timeout);
404 }
405
406 return false0;
407}
408
409static int
410turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
411{
412 timeout_t wheel_timeout;
413 struct timespec now;
414
415 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0)))
416 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 416, __FUNCTION__, "Could not get monotonic time");
417
418 timeouts_update(t->wheel,
419 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
420
421 wheel_timeout = timeouts_timeout(t->wheel);
422 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
423 goto infinite_timeout;
424
425 if (wheel_timeout == 0) {
426 if (!process_pending_timers(tq, t, epoll_fd))
427 goto infinite_timeout;
428
429 wheel_timeout = timeouts_timeout(t->wheel);
430 if (wheel_timeout == 0)
431 goto infinite_timeout;
432 }
433
434 return (int)wheel_timeout;
435
436infinite_timeout:
437 return -1;
438}
439
440static void *thread_io_loop(void *data)
441{
442 struct lwan_thread *t = data;
443 int epoll_fd = t->epoll_fd;
444 const int read_pipe_fd = t->pipe_fd[0];
445 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id14
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id15 = (1024); lwan_tmp_id14 > lwan_tmp_id15
? lwan_tmp_id15 : lwan_tmp_id14; });
446 struct lwan *lwan = t->lwan;
447 struct epoll_event *events;
448 struct coro_switcher switcher;
449 struct timeout_queue tq;
450
451 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 452, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
452 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 452, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1);
453 lwan_set_thread_name("worker");
454
455 events = calloc((size_t)max_events, sizeof(*events));
456 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
457 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"
, 457, __FUNCTION__, "Could not allocate memory for events");
458
459 update_date_cache(t);
460
461 timeout_queue_init(&tq, lwan);
462
463 pthread_barrier_wait(&lwan->thread.barrier);
464
465 for (;;) {
466 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
467 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
468
469 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
470 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
471 break;
472 continue;
473 }
474
475 for (struct epoll_event *event = events; n_fds--; event++) {
476 struct lwan_connection *conn;
477
478 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
479 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
480 epoll_fd);
481 continue;
482 }
483
484 conn = event->data.ptr;
485
486 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))) {
487 timeout_queue_expire(&tq, conn);
488 continue;
489 }
490
491 resume_coro(&tq, conn, epoll_fd);
492 timeout_queue_move_to_last(&tq, conn);
493 }
494 }
495
496 pthread_barrier_wait(&lwan->thread.barrier);
497
498 timeout_queue_expire_all(&tq);
499 free(events);
500
501 return NULL((void*)0);
502}
503
504static void create_thread(struct lwan *l, struct lwan_thread *thread,
505 const size_t n_queue_fds)
506{
507 int ignore;
508 pthread_attr_t attr;
509
510 memset(thread, 0, sizeof(*thread));
511 thread->lwan = l;
512
513 thread->wheel = timeouts_open(&ignore);
514 if (!thread->wheel)
515 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 515, __FUNCTION__, "Could not create timer wheel");
516
517 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
518 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 518, __FUNCTION__, "epoll_create");
519
520 if (pthread_attr_init(&attr))
521 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 521, __FUNCTION__, "pthread_attr_init");
522
523 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
524 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 524, __FUNCTION__, "pthread_attr_setscope");
525
526 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
527 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 527, __FUNCTION__, "pthread_attr_setdetachstate");
528
529#if defined(HAVE_EVENTFD)
530 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
531 if (efd < 0)
532 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 532, __FUNCTION__, "eventfd");
533
534 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
535#else
536 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
537 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 537, __FUNCTION__, "pipe");
538#endif
539
540 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
541 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
542 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 542, __FUNCTION__, "epoll_ctl");
543
544 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
545 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 545, __FUNCTION__, "pthread_create");
546
547 if (pthread_attr_destroy(&attr))
548 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 548, __FUNCTION__, "pthread_attr_destroy");
549
550 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
551 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 552, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
552 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 552, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds);
553 }
554}
555
556void lwan_thread_nudge(struct lwan_thread *t)
557{
558 uint64_t event = 1;
559
560 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0)))
561 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 561, __FUNCTION__, "write");
562}
563
564void lwan_thread_add_client(struct lwan_thread *t, int fd)
565{
566 for (int i = 0; i < 10; i++) {
567 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
568
569 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
570 return;
571
572 /* Queue is full; nudge the thread to consume it. */
573 lwan_thread_nudge(t);
574 }
575
576 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 576, __FUNCTION__, "Dropping connection %d", fd);
577 /* FIXME: send "busy" response now, even without receiving request? */
578 close(fd);
579}
580
581#if defined(__linux__1) && defined(__x86_64__1)
582static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
583{
584 char path[PATH_MAX4096];
585
586 for (unsigned int i = 0; i < l->n_cpus; i++) {
587 FILE *sib;
588 uint32_t id, sibling;
589 char separator;
590
591 snprintf(path, sizeof(path),
592 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
593 i);
594
595 sib = fopen(path, "re");
596 if (!sib) {
597 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"
, 598, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
598 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 598, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path);
599 return false0;
600 }
601
602 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
603 case 2: /* No SMT */
604 siblings[i] = id;
605 break;
606 case 3: /* SMT */
607 if (!(separator == ',' || separator == '-')) {
608 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"
, 608, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
);
609 __builtin_unreachable();
610 }
611
612 siblings[i] = sibling;
613 break;
614 default:
615 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 615, __FUNCTION__, "%s has invalid format", path);
616 __builtin_unreachable();
617 }
618
619
620 fclose(sib);
621 }
622
623 return true1;
624}
625
626static void
627siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
628{
629 int *seen = alloca(l->n_cpus * sizeof(int))__builtin_alloca (l->n_cpus * sizeof(int));
630 int n_schedtbl = 0;
631
632 for (uint32_t i = 0; i < l->n_cpus; i++)
633 seen[i] = -1;
634
635 for (uint32_t i = 0; i < l->n_cpus; i++) {
636 if (seen[siblings[i]] < 0) {
637 seen[siblings[i]] = (int)i;
638 } else {
639 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
640 schedtbl[n_schedtbl++] = i;
641 }
642 }
643
644 if (!n_schedtbl)
645 memcpy(schedtbl, seen, l->n_cpus * sizeof(int));
646}
647
648static void
649topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
650{
651 uint32_t *siblings = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
652
653 if (!read_cpu_topology(l, siblings)) {
11
←
Assuming the condition is true
→
12
←
Taking true branch
→
654 for (uint32_t i = 0; i < n_threads; i++)
13
←
Assuming 'i' is >= 'n_threads'
→
14
←
Loop condition is false. Execution continues on line 654
→
655 schedtbl[i] = (i / 2) % l->thread.count;
656 } else {
657 uint32_t *affinity = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
658
659 siblings_to_schedtbl(l, siblings, affinity);
660
661 for (uint32_t i = 0; i < n_threads; i++)
662 schedtbl[i] = affinity[i % l->n_cpus];
663 }
664}
665
666static void
667adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
668{
669 for (uint32_t i = 0; i < l->thread.count; i++) {
17
←
Assuming 'i' is >= field 'count'
→
18
←
Loop condition is false. Execution continues on line 669
→
670 cpu_set_t set;
671
672 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0);
673 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; }));
674
675 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
676 &set))
677 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"
, 677, __FUNCTION__, "Could not set affinity for thread %d", i
);
678 }
679}
680#elif defined(__x86_64__1)
681static void
682topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
683{
684 for (uint32_t i = 0; i < n_threads; i++)
685 schedtbl[i] = (i / 2) % l->thread.count;
686}
687
688static void
689adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
690{
691}
692#endif
693
694void lwan_thread_init(struct lwan *l)
695{
696 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
→
2
←
Taking false branch
→
697 (unsigned)l->thread.count + 1))
698 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 698, __FUNCTION__, "Could not create barrier");
699
700 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 700, __FUNCTION__, "Initializing threads");
701
702 l->thread.threads =
703 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
704 if (!l->thread.threads)
3
←
Assuming field 'threads' is non-null
→
4
←
Taking false branch
→
705 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"
, 705, __FUNCTION__, "Could not allocate memory for threads");
706
707 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_id16 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id17 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id16 > lwan_tmp_id17 ? lwan_tmp_id17 : lwan_tmp_id16
; })
5
←
Assuming 'lwan_tmp_id4' is <= 'lwan_tmp_id5'
→
6
←
'?' condition is false
→
708 (size_t)(2 * lwan_socket_get_backlog_size()))({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id16 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id17 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id16 > lwan_tmp_id17 ? lwan_tmp_id17 : lwan_tmp_id16
; });
709 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"
, 709, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds);
710 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 713
→
711 create_thread(l, &l->thread.threads[i], n_queue_fds);
712
713 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
714#ifdef __x86_64__1
715 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; })]
716 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })];
717 /*
718 * Pre-schedule each file descriptor, to reduce some operations in the
719 * fast path.
720 *
721 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
722 * them can fill up a cache line. Assume siblings share cache lines and
723 * use the CPU topology to group two connections per cache line in such
724 * a way that false sharing is avoided.
725 */
726 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
727 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
728
729 topology_to_schedtbl(l, schedtbl, n_threads);
10
←
Calling 'topology_to_schedtbl'
→
15
←
Returning from 'topology_to_schedtbl'
→
730
731 n_threads--; /* Transform count into mask for AND below */
732 adjust_threads_affinity(l, schedtbl, n_threads);
16
←
Calling 'adjust_threads_affinity'
→
19
←
Returning from 'adjust_threads_affinity'
→
733 for (unsigned int i = 0; i < total_conns; i++)
20
←
Assuming 'i' is < 'total_conns'
→
21
←
Loop condition is true. Entering loop body
→
734 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
22
←
Array subscript is undefined
735#else
736 for (unsigned int i = 0; i < total_conns; i++)
737 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
738#endif
739
740 pthread_barrier_wait(&l->thread.barrier);
741
742 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"
, 742, __FUNCTION__, "Worker threads created and ready to serve"
);
743}
744
745void lwan_thread_shutdown(struct lwan *l)
746{
747 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 747, __FUNCTION__, "Shutting down threads");
748
749 for (unsigned int i = 0; i < l->thread.count; i++) {
750 struct lwan_thread *t = &l->thread.threads[i];
751
752 close(t->epoll_fd);
753 lwan_thread_nudge(t);
754 }
755
756 pthread_barrier_wait(&l->thread.barrier);
757 pthread_barrier_destroy(&l->thread.barrier);
758
759 for (unsigned int i = 0; i < l->thread.count; i++) {
760 struct lwan_thread *t = &l->thread.threads[i];
761
762 close(t->pipe_fd[0]);
763#if !defined(HAVE_EVENTFD)
764 close(t->pipe_fd[1]);
765#endif
766
767 pthread_join(l->thread.threads[i].self, NULL((void*)0));
768 spsc_queue_free(&t->pending_fds);
769 timeouts_close(t->wheel);
770 }
771
772 free(l->thread.threads);
773}