Bug Summary

File:lwan-thread.c
Warning:line 661, 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/2020-07-11-181412-1291097-1 -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);
138
139 if (LIKELY(conn->flags & CONN_IS_KEEP_ALIVE)__builtin_expect((!!(conn->flags & CONN_IS_KEEP_ALIVE)
), (1))) {
140 if (next_request && *next_request) {
141 conn->flags |= CONN_CORK;
142 coro_yield(coro, CONN_CORO_WANT_WRITE);
143 } else {
144 conn->flags &= ~CONN_CORK;
145 coro_yield(coro, CONN_CORO_WANT_READ);
146 }
147 } else {
148 graceful_close(lwan, conn, request_buffer);
149 break;
150 }
151
152 lwan_strbuf_reset(&strbuf);
153 coro_deferred_run(coro, init_gen);
154
155 /* Only allow flags from config. */
156 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
157 next_request = helper.next_request;
158 }
159
160 coro_yield(coro, CONN_CORO_ABORT);
161 __builtin_unreachable();
162}
163
164static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
165conn_flags_to_epoll_events(enum lwan_connection_flags flags)
166{
167 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
168 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
169 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
170 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
171 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
172 };
173
174 return map[flags & CONN_EVENTS_MASK];
175}
176
177static void update_epoll_flags(int fd,
178 struct lwan_connection *conn,
179 int epoll_fd,
180 enum lwan_connection_coro_yield yield_result)
181{
182 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
183 [CONN_CORO_YIELD] = 0,
184
185 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
186 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
187 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
188
189 /* While the coro is suspended, we're not interested in either EPOLLIN
190 * or EPOLLOUT events. We still want to track this fd in epoll, though,
191 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
192 * are set. */
193 [CONN_CORO_SUSPEND_TIMER] = CONN_SUSPENDED_TIMER,
194 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = CONN_SUSPENDED_ASYNC_AWAIT,
195
196 /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
197 * would have to be stored and restored -- however, resuming as if the
198 * client coroutine is interested in a write event always guarantees that
199 * they'll be resumed as they're TCP sockets. There's a good chance that
200 * trying to read from a socket after resuming a coroutine will succeed,
201 * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
202 * yield with CONN_CORO_WANT_READ anyway. */
203 [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
204 };
205 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
206 [CONN_CORO_YIELD] = ~0,
207
208 [CONN_CORO_WANT_READ_WRITE] = ~0,
209 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
210 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
211
212 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
213 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
214 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
215 };
216 enum lwan_connection_flags prev_flags = conn->flags;
217
218 conn->flags |= or_mask[yield_result];
219 conn->flags &= and_mask[yield_result];
220
221 if (conn->flags == prev_flags)
222 return;
223
224 struct epoll_event event = {
225 .events = conn_flags_to_epoll_events(conn->flags),
226 .data.ptr = conn,
227 };
228
229 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0)))
230 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 230, __FUNCTION__, "epoll_ctl");
231}
232
233static void clear_async_await_flag(void *data)
234{
235 struct lwan_connection *async_fd_conn = data;
236
237 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
238}
239
240static enum lwan_connection_coro_yield
241resume_async(struct timeout_queue *tq,
242 enum lwan_connection_coro_yield yield_result,
243 int64_t from_coro,
244 struct lwan_connection *conn,
245 int epoll_fd)
246{
247 static const enum lwan_connection_flags to_connection_flags[] = {
248 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
249 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
250 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
251 };
252 int await_fd = (int)((uint64_t)from_coro >> 32);
253 enum lwan_connection_flags flags;
254 int op;
255
256 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"
, 256, __extension__ __PRETTY_FUNCTION__); }));
257 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"
, 258, __extension__ __PRETTY_FUNCTION__); }))
258 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"
, 258, __extension__ __PRETTY_FUNCTION__); }));
259
260 flags = to_connection_flags[yield_result];
261
262 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
263 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))) {
264 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1)))
265 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
266
267 op = EPOLL_CTL_MOD3;
268 } else {
269 op = EPOLL_CTL_ADD1;
270 flags |= CONN_ASYNC_AWAIT;
271 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
272 }
273
274 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
275 .data.ptr = conn};
276 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))) {
277 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
278 await_fd_conn->flags |= flags;
279 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
280 }
281
282 return CONN_CORO_ABORT;
283}
284
285static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
286 struct lwan_connection *conn,
287 int epoll_fd)
288{
289 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"
, 289, __extension__ __PRETTY_FUNCTION__); }));
290
291 int64_t from_coro = coro_resume(conn->coro);
292 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
293
294 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
295 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
296
297 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
298 return timeout_queue_expire(tq, conn);
299
300 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
301 epoll_fd, yield_result);
302}
303
304static void update_date_cache(struct lwan_thread *thread)
305{
306 time_t now = time(NULL((void*)0));
307
308 lwan_format_rfc_time(now, thread->date.date);
309 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
310 thread->date.expires);
311}
312
313static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
314 struct coro_switcher *switcher,
315 struct timeout_queue *tq)
316{
317 struct lwan_thread *t = conn->thread;
318
319 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"
, 319, __extension__ __PRETTY_FUNCTION__); }));
320 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"
, 320, __extension__ __PRETTY_FUNCTION__); }));
321 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"
, 321, __extension__ __PRETTY_FUNCTION__); }));
322 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"
, 323, __extension__ __PRETTY_FUNCTION__); }))
323 (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"
, 323, __extension__ __PRETTY_FUNCTION__); }));
324
325 *conn = (struct lwan_connection) {
326 .coro = coro_new(switcher, process_request_coro, conn),
327 .flags = CONN_EVENTS_READ,
328 .time_to_expire = tq->current_time + tq->move_to_last_bump,
329 .thread = t,
330 };
331 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
332 conn->flags = 0;
333 lwan_status_error("Could not create coroutine")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 333, __FUNCTION__, "Could not create coroutine");
334 return;
335 }
336
337 timeout_queue_insert(tq, conn);
338}
339
340static void accept_nudge(int pipe_fd,
341 struct lwan_thread *t,
342 struct lwan_connection *conns,
343 struct timeout_queue *tq,
344 struct coro_switcher *switcher,
345 int epoll_fd)
346{
347 uint64_t event;
348 int new_fd;
349
350 /* Errors are ignored here as pipe_fd serves just as a way to wake the
351 * thread from epoll_wait(). It's fine to consume the queue at this
352 * point, regardless of the error type. */
353 (void)read(pipe_fd, &event, sizeof(event));
354
355 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
356 struct lwan_connection *conn = &conns[new_fd];
357 struct epoll_event ev = {
358 .data.ptr = conn,
359 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
360 };
361
362 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1)))
363 spawn_coro(conn, switcher, tq);
364 }
365
366 timeouts_add(t->wheel, &tq->timeout, 1000);
367}
368
369static bool_Bool process_pending_timers(struct timeout_queue *tq,
370 struct lwan_thread *t,
371 int epoll_fd)
372{
373 struct timeout *timeout;
374 bool_Bool should_expire_timers = false0;
375
376 while ((timeout = timeouts_get(t->wheel))) {
377 struct lwan_request *request;
378
379 if (timeout == &tq->timeout) {
380 should_expire_timers = true1;
381 continue;
382 }
383
384 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));
385
386 update_epoll_flags(request->fd, request->conn, epoll_fd,
387 CONN_CORO_RESUME);
388 }
389
390 if (should_expire_timers) {
391 timeout_queue_expire_waiting(tq);
392
393 /* tq timeout expires every 1000ms if there are connections, so
394 * update the date cache at this point as well. */
395 update_date_cache(t);
396
397 if (!timeout_queue_empty(tq)) {
398 timeouts_add(t->wheel, &tq->timeout, 1000);
399 return true1;
400 }
401
402 timeouts_del(t->wheel, &tq->timeout);
403 }
404
405 return false0;
406}
407
408static int
409turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
410{
411 timeout_t wheel_timeout;
412 struct timespec now;
413
414 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0)))
415 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 415, __FUNCTION__, "Could not get monotonic time");
416
417 timeouts_update(t->wheel,
418 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
419
420 wheel_timeout = timeouts_timeout(t->wheel);
421 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
422 goto infinite_timeout;
423
424 if (wheel_timeout == 0) {
425 if (!process_pending_timers(tq, t, epoll_fd))
426 goto infinite_timeout;
427
428 wheel_timeout = timeouts_timeout(t->wheel);
429 if (wheel_timeout == 0)
430 goto infinite_timeout;
431 }
432
433 return (int)wheel_timeout;
434
435infinite_timeout:
436 return -1;
437}
438
439static void *thread_io_loop(void *data)
440{
441 struct lwan_thread *t = data;
442 int epoll_fd = t->epoll_fd;
443 const int read_pipe_fd = t->pipe_fd[0];
444 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; });
445 struct lwan *lwan = t->lwan;
446 struct epoll_event *events;
447 struct coro_switcher switcher;
448 struct timeout_queue tq;
449
450 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 451, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
451 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 451, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1);
452 lwan_set_thread_name("worker");
453
454 events = calloc((size_t)max_events, sizeof(*events));
455 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
456 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"
, 456, __FUNCTION__, "Could not allocate memory for events");
457
458 update_date_cache(t);
459
460 timeout_queue_init(&tq, lwan);
461
462 pthread_barrier_wait(&lwan->thread.barrier);
463
464 for (;;) {
465 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
466 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
467
468 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
469 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
470 break;
471 continue;
472 }
473
474 for (struct epoll_event *event = events; n_fds--; event++) {
475 struct lwan_connection *conn;
476
477 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
478 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
479 epoll_fd);
480 continue;
481 }
482
483 conn = event->data.ptr;
484
485 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))) {
486 timeout_queue_expire(&tq, conn);
487 continue;
488 }
489
490 resume_coro(&tq, conn, epoll_fd);
491 timeout_queue_move_to_last(&tq, conn);
492 }
493 }
494
495 pthread_barrier_wait(&lwan->thread.barrier);
496
497 timeout_queue_expire_all(&tq);
498 free(events);
499
500 return NULL((void*)0);
501}
502
503static void create_thread(struct lwan *l, struct lwan_thread *thread,
504 const size_t n_queue_fds)
505{
506 int ignore;
507 pthread_attr_t attr;
508
509 memset(thread, 0, sizeof(*thread));
510 thread->lwan = l;
511
512 thread->wheel = timeouts_open(&ignore);
513 if (!thread->wheel)
514 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 514, __FUNCTION__, "Could not create timer wheel");
515
516 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
517 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 517, __FUNCTION__, "epoll_create");
518
519 if (pthread_attr_init(&attr))
520 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 520, __FUNCTION__, "pthread_attr_init");
521
522 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
523 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 523, __FUNCTION__, "pthread_attr_setscope");
524
525 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
526 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 526, __FUNCTION__, "pthread_attr_setdetachstate");
527
528#if defined(HAVE_EVENTFD)
529 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
530 if (efd < 0)
531 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 531, __FUNCTION__, "eventfd");
532
533 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
534#else
535 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
536 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 536, __FUNCTION__, "pipe");
537#endif
538
539 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
540 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
541 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 541, __FUNCTION__, "epoll_ctl");
542
543 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
544 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 544, __FUNCTION__, "pthread_create");
545
546 if (pthread_attr_destroy(&attr))
547 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 547, __FUNCTION__, "pthread_attr_destroy");
548
549 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
550 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 551, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
551 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 551, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds);
552 }
553}
554
555void lwan_thread_nudge(struct lwan_thread *t)
556{
557 uint64_t event = 1;
558
559 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0)))
560 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 560, __FUNCTION__, "write");
561}
562
563void lwan_thread_add_client(struct lwan_thread *t, int fd)
564{
565 for (int i = 0; i < 10; i++) {
566 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
567
568 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
569 return;
570
571 /* Queue is full; nudge the thread to consume it. */
572 lwan_thread_nudge(t);
573 }
574
575 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 575, __FUNCTION__, "Dropping connection %d", fd);
576 /* FIXME: send "busy" response now, even without receiving request? */
577 close(fd);
578}
579
580#if defined(__linux__1) && defined(__x86_64__1)
581static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
582{
583 char path[PATH_MAX4096];
584
585 for (unsigned int i = 0; i < l->n_cpus; i++) {
586 FILE *sib;
587 uint32_t id, sibling;
588 char separator;
589
590 snprintf(path, sizeof(path),
591 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
592 i);
593
594 sib = fopen(path, "re");
595 if (!sib) {
596 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"
, 597, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
597 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 597, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path);
598 return false0;
599 }
600
601 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
602 case 2: /* No SMT */
603 siblings[i] = id;
604 break;
605 case 3: /* SMT */
606 if (!(separator == ',' || separator == '-')) {
607 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"
, 607, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
);
608 __builtin_unreachable();
609 }
610
611 siblings[i] = sibling;
612 break;
613 default:
614 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 614, __FUNCTION__, "%s has invalid format", path);
615 __builtin_unreachable();
616 }
617
618
619 fclose(sib);
620 }
621
622 return true1;
623}
624
625static void
626siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
627{
628 int *seen = alloca(l->n_cpus * sizeof(int))__builtin_alloca (l->n_cpus * sizeof(int));
629 int n_schedtbl = 0;
630
631 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 634
→
632 seen[i] = -1;
633
634 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 643
→
635 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
→
636 seen[siblings[i]] = (int)i;
637 } else {
638 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
639 schedtbl[n_schedtbl++] = i;
640 }
641 }
642
643 if (!n_schedtbl
31.1
'n_schedtbl' is 2
)
32
←
Taking false branch
→
644 memcpy(schedtbl, seen, l->n_cpus * sizeof(int));
645}
646
647static void
648topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
649{
650 uint32_t *siblings = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
651
652 if (!read_cpu_topology(l, siblings)) {
11
←
Assuming the condition is false
→
12
←
Taking false branch
→
653 for (uint32_t i = 0; i < n_threads; i++)
654 schedtbl[i] = (i / 2) % l->thread.count;
655 } else {
656 uint32_t *affinity = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
657
658 siblings_to_schedtbl(l, siblings, affinity);
13
←
Calling 'siblings_to_schedtbl'
→
33
←
Returning from 'siblings_to_schedtbl'
→
659
660 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
→
661 schedtbl[i] = affinity[i % l->n_cpus];
40
←
Assigned value is garbage or undefined
662 }
663}
664
665static void
666adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
667{
668 for (uint32_t i = 0; i < l->thread.count; i++) {
669 cpu_set_t set;
670
671 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0);
672 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; }));
673
674 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
675 &set))
676 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"
, 676, __FUNCTION__, "Could not set affinity for thread %d", i
);
677 }
678}
679#elif defined(__x86_64__1)
680static void
681topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
682{
683 for (uint32_t i = 0; i < n_threads; i++)
684 schedtbl[i] = (i / 2) % l->thread.count;
685}
686
687static void
688adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
689{
690}
691#endif
692
693void lwan_thread_init(struct lwan *l)
694{
695 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
→
2
←
Taking false branch
→
696 (unsigned)l->thread.count + 1))
697 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 697, __FUNCTION__, "Could not create barrier");
698
699 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 699, __FUNCTION__, "Initializing threads");
700
701 l->thread.threads =
702 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
703 if (!l->thread.threads)
3
←
Assuming field 'threads' is non-null
→
4
←
Taking false branch
→
704 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"
, 704, __FUNCTION__, "Could not allocate memory for threads");
705
706 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
→
707 (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
; });
708 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"
, 708, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds);
709 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 712
→
710 create_thread(l, &l->thread.threads[i], n_queue_fds);
711
712 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
713#ifdef __x86_64__1
714 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; })]
715 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })];
716 /*
717 * Pre-schedule each file descriptor, to reduce some operations in the
718 * fast path.
719 *
720 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
721 * them can fill up a cache line. Assume siblings share cache lines and
722 * use the CPU topology to group two connections per cache line in such
723 * a way that false sharing is avoided.
724 */
725 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
726 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
727
728 topology_to_schedtbl(l, schedtbl, n_threads);
10
←
Calling 'topology_to_schedtbl'
→
729
730 n_threads--; /* Transform count into mask for AND below */
731 adjust_threads_affinity(l, schedtbl, n_threads);
732 for (unsigned int i = 0; i < total_conns; i++)
733 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
734#else
735 for (unsigned int i = 0; i < total_conns; i++)
736 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
737#endif
738
739 pthread_barrier_wait(&l->thread.barrier);
740
741 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"
, 741, __FUNCTION__, "Worker threads created and ready to serve"
);
742}
743
744void lwan_thread_shutdown(struct lwan *l)
745{
746 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 746, __FUNCTION__, "Shutting down threads");
747
748 for (unsigned int i = 0; i < l->thread.count; i++) {
749 struct lwan_thread *t = &l->thread.threads[i];
750
751 close(t->epoll_fd);
752 lwan_thread_nudge(t);
753 }
754
755 pthread_barrier_wait(&l->thread.barrier);
756 pthread_barrier_destroy(&l->thread.barrier);
757
758 for (unsigned int i = 0; i < l->thread.count; i++) {
759 struct lwan_thread *t = &l->thread.threads[i];
760
761 close(t->pipe_fd[0]);
762#if !defined(HAVE_EVENTFD)
763 close(t->pipe_fd[1]);
764#endif
765
766 pthread_join(l->thread.threads[i].self, NULL((void*)0));
767 spsc_queue_free(&t->pending_fds);
768 timeouts_close(t->wheel);
769 }
770
771 free(l->thread.threads);
772}