Bug Summary

File:lib/lwan-thread.c
Warning:line 664, column 9
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 -mrelocation-model pic -pic-level 2 -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -fno-plt -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -resource-dir /usr/lib/clang/9.0.1 -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/9.0.1/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 -fobjc-runtime=gcc -fdiagnostics-show-option -analyzer-output=html -faddrsig -o /home/buildbot/lwan-worker/clang-analyze/CLANG/2020-04-15-025140-3801729-1 -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 EINTR4:
82 continue;
83 case EAGAIN11:
84 coro_yield(conn->coro, CONN_CORO_WANT_READ);
85 continue;
86 default:
87 return;
88 }
89 }
90
91 coro_yield(conn->coro, CONN_CORO_YIELD);
92 }
93
94 /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
95}
96
97__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
98 void *data)
99{
100 /* NOTE: This function should not return; coro_yield should be used
101 * instead. This ensures the storage for `strbuf` is alive when the
102 * coroutine ends and lwan_strbuf_free() is called. */
103 struct lwan_connection *conn = data;
104 struct lwan *lwan = conn->thread->lwan;
105 int fd = lwan_connection_get_fd(lwan, conn);
106 enum lwan_request_flags flags = lwan->config.request_flags;
107 struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
108 char request_buffer[DEFAULT_BUFFER_SIZE4096];
109 struct lwan_value buffer = {.value = request_buffer, .len = 0};
110 char *next_request = NULL((void*)0);
111 struct lwan_proxy proxy;
112
113 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
114
115 const size_t init_gen = 1; /* 1 call to coro_defer() */
116 assert(init_gen == coro_deferred_get_generation(coro))((void) sizeof ((init_gen == coro_deferred_get_generation(coro
)) ? 1 : 0), __extension__ ({ if (init_gen == coro_deferred_get_generation
(coro)) ; else __assert_fail ("init_gen == coro_deferred_get_generation(coro)"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 116, __extension__ __PRETTY_FUNCTION__); }))
;
117
118 while (true1) {
119 struct lwan_request request = {.conn = conn,
120 .fd = fd,
121 .response = {.buffer = &strbuf},
122 .flags = flags,
123 .proxy = &proxy};
124
125 next_request =
126 lwan_process_request(lwan, &request, &buffer, next_request);
127
128 if (coro_deferred_get_generation(coro) > ((2 * LWAN_ARRAY_INCREMENT16) / 3)) {
129 /* Batch execution of coro_defers() up to 2/3 LWAN_ARRAY_INCREMENT times,
130 * to avoid moving deferred array to heap in most cases. (This is to give
131 * some slack to the next request being processed by this coro.) */
132 coro_deferred_run(coro, init_gen);
133 }
134
135 if (LIKELY(conn->flags & CONN_IS_KEEP_ALIVE)__builtin_expect((!!(conn->flags & CONN_IS_KEEP_ALIVE)
), (1))
) {
136 if (next_request && *next_request) {
137 conn->flags |= CONN_CORK;
138 coro_yield(coro, CONN_CORO_WANT_WRITE);
139 } else {
140 conn->flags &= ~CONN_CORK;
141 coro_yield(coro, CONN_CORO_WANT_READ);
142 }
143 } else {
144 graceful_close(lwan, conn, request_buffer);
145 break;
146 }
147
148 lwan_strbuf_reset(&strbuf);
149
150 /* Only allow flags from config. */
151 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
152 }
153
154 coro_yield(coro, CONN_CORO_ABORT);
155 __builtin_unreachable();
156}
157
158#undef REQUEST_FLAG
159
160static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
161conn_flags_to_epoll_events(enum lwan_connection_flags flags)
162{
163 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
164 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
165 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
166 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
167 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
168 [CONN_EVENTS_ASYNC_READ] = EPOLLETEPOLLET | EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP | EPOLLONESHOTEPOLLONESHOT,
169 [CONN_EVENTS_ASYNC_WRITE] = EPOLLETEPOLLET | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP | EPOLLONESHOTEPOLLONESHOT,
170 [CONN_EVENTS_ASYNC_READ_WRITE] = EPOLLETEPOLLET | EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP | EPOLLONESHOTEPOLLONESHOT,
171 };
172
173 return map[flags & CONN_EVENTS_MASK];
174}
175
176#if defined(__linux__1)
177# define CONN_EVENTS_RESUMECONN_EVENTS_READ_WRITE CONN_EVENTS_READ_WRITE
178#else
179/* Kqueue doesn't like when you filter on both read and write, so
180 * wait only on write when resuming a coro suspended by a timer.
181 * The I/O wrappers should yield if trying to read without anything
182 * in the buffer, changing the filter to only read, so this is OK. */
183# define CONN_EVENTS_RESUMECONN_EVENTS_READ_WRITE CONN_EVENTS_WRITE
184#endif
185
186static void update_epoll_flags(int fd,
187 struct lwan_connection *conn,
188 int epoll_fd,
189 enum lwan_connection_coro_yield yield_result)
190{
191 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
192 [CONN_CORO_YIELD] = 0,
193
194 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
195 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
196 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
197
198 /* While the coro is suspended, we're not interested in either EPOLLIN
199 * or EPOLLOUT events. We still want to track this fd in epoll, though,
200 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
201 * are set. */
202 [CONN_CORO_SUSPEND_TIMER] = CONN_SUSPENDED_TIMER,
203 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = CONN_SUSPENDED_ASYNC_AWAIT,
204
205 /* Either EPOLLIN or EPOLLOUT have to be set here. There's no need to
206 * know which event, because they were both cleared when the coro was
207 * suspended. So set both flags here. This works because EPOLLET isn't
208 * used. */
209 [CONN_CORO_RESUME] = CONN_EVENTS_RESUMECONN_EVENTS_READ_WRITE,
210
211 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_ASYNC_READ,
212 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_ASYNC_WRITE,
213 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_ASYNC_READ_WRITE,
214 };
215 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
216 [CONN_CORO_YIELD] = ~0,
217
218 [CONN_CORO_WANT_READ_WRITE] = ~0,
219 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
220 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
221
222 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
223 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
224 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
225
226 [CONN_CORO_ASYNC_AWAIT_READ] = ~0,
227 [CONN_CORO_ASYNC_AWAIT_WRITE] = ~0,
228 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = ~0,
229 };
230 enum lwan_connection_flags prev_flags = conn->flags;
231
232 conn->flags |= or_mask[yield_result];
233 conn->flags &= and_mask[yield_result];
234
235 if (conn->flags == prev_flags)
236 return;
237
238 struct epoll_event event = {
239 .events = conn_flags_to_epoll_events(conn->flags),
240 .data.ptr = conn,
241 };
242
243 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0))
)
244 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 244, __FUNCTION__, "epoll_ctl")
;
245}
246
247static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
248 struct lwan_connection *conn,
249 int epoll_fd)
250{
251 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"
, 251, __extension__ __PRETTY_FUNCTION__); }))
;
252
253 int64_t from_coro = coro_resume(conn->coro);
254 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
255
256 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
257 return timeout_queue_expire(tq, conn);
258
259 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0))) {
260 assert(yield_result >= CONN_CORO_ASYNC_AWAIT_READ &&((void) sizeof ((yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_RESUME) ? 1 : 0
), __extension__ ({ if (yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_RESUME) ; else
__assert_fail ("yield_result >= CONN_CORO_ASYNC_AWAIT_READ && yield_result <= CONN_CORO_ASYNC_RESUME"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 261, __extension__ __PRETTY_FUNCTION__); }))
261 yield_result <= CONN_CORO_ASYNC_RESUME)((void) sizeof ((yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_RESUME) ? 1 : 0
), __extension__ ({ if (yield_result >= CONN_CORO_ASYNC_AWAIT_READ
&& yield_result <= CONN_CORO_ASYNC_RESUME) ; else
__assert_fail ("yield_result >= CONN_CORO_ASYNC_AWAIT_READ && yield_result <= CONN_CORO_ASYNC_RESUME"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 261, __extension__ __PRETTY_FUNCTION__); }))
;
262
263 static const enum lwan_connection_flags to_connection_flags[] = {
264 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_ASYNC_READ,
265 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_ASYNC_WRITE,
266 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_ASYNC_READ_WRITE,
267 [CONN_CORO_ASYNC_RESUME] = 0,
268 };
269 struct epoll_event event = {
270 .events =
271 conn_flags_to_epoll_events(to_connection_flags[yield_result]),
272 .data.ptr = conn,
273 };
274 int await_fd = (int)((uint64_t)from_coro >> 32);
275 int op;
276
277 assert(event.events != 0)((void) sizeof ((event.events != 0) ? 1 : 0), __extension__ (
{ if (event.events != 0) ; else __assert_fail ("event.events != 0"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 277, __extension__ __PRETTY_FUNCTION__); }))
;
278 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"
, 278, __extension__ __PRETTY_FUNCTION__); }))
;
279
280 if (yield_result == CONN_CORO_ASYNC_RESUME) {
281 op = EPOLL_CTL_DEL2;
282 yield_result = CONN_CORO_RESUME;
283 } else {
284 op = EPOLL_CTL_ADD1;
285 yield_result = CONN_CORO_SUSPEND_ASYNC_AWAIT;
286 }
287
288 if (UNLIKELY(epoll_ctl(epoll_fd, op, await_fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, op, await_fd, &event
) < 0)), (0))
)
289 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 289, __FUNCTION__, "epoll_ctl")
;
290 }
291
292 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
293 epoll_fd, yield_result);
294}
295
296static void update_date_cache(struct lwan_thread *thread)
297{
298 time_t now = time(NULL((void*)0));
299
300 lwan_format_rfc_time(now, thread->date.date);
301 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
302 thread->date.expires);
303}
304
305static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
306 struct coro_switcher *switcher,
307 struct timeout_queue *tq)
308{
309 struct lwan_thread *t = conn->thread;
310
311 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"
, 311, __extension__ __PRETTY_FUNCTION__); }))
;
312 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"
, 312, __extension__ __PRETTY_FUNCTION__); }))
;
313 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"
, 313, __extension__ __PRETTY_FUNCTION__); }))
;
314 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"
, 315, __extension__ __PRETTY_FUNCTION__); }))
315 (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"
, 315, __extension__ __PRETTY_FUNCTION__); }))
;
316
317 *conn = (struct lwan_connection) {
318 .coro = coro_new(switcher, process_request_coro, conn),
319 .flags = CONN_EVENTS_READ,
320 .time_to_expire = tq->current_time + tq->move_to_last_bump,
321 .thread = t,
322 };
323 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
324 conn->flags = 0;
325 lwan_status_error("Could not create coroutine")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 325, __FUNCTION__, "Could not create coroutine")
;
326 return;
327 }
328
329 timeout_queue_insert(tq, conn);
330}
331
332static void accept_nudge(int pipe_fd,
333 struct lwan_thread *t,
334 struct lwan_connection *conns,
335 struct timeout_queue *tq,
336 struct coro_switcher *switcher,
337 int epoll_fd)
338{
339 uint64_t event;
340 int new_fd;
341
342 /* Errors are ignored here as pipe_fd serves just as a way to wake the
343 * thread from epoll_wait(). It's fine to consume the queue at this
344 * point, regardless of the error type. */
345 (void)read(pipe_fd, &event, sizeof(event));
346
347 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
348 struct lwan_connection *conn = &conns[new_fd];
349 struct epoll_event ev = {
350 .data.ptr = conn,
351 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
352 };
353
354 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1))
)
355 spawn_coro(conn, switcher, tq);
356 }
357
358 timeouts_add(t->wheel, &tq->timeout, 1000);
359}
360
361static bool_Bool process_pending_timers(struct timeout_queue *tq,
362 struct lwan_thread *t,
363 int epoll_fd)
364{
365 struct timeout *timeout;
366 bool_Bool should_expire_timers = false0;
367
368 while ((timeout = timeouts_get(t->wheel))) {
369 struct lwan_request *request;
370
371 if (timeout == &tq->timeout) {
372 should_expire_timers = true1;
373 continue;
374 }
375
376 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))
;
377
378 update_epoll_flags(request->fd, request->conn, epoll_fd,
379 CONN_CORO_RESUME);
380 }
381
382 if (should_expire_timers) {
383 timeout_queue_expire_waiting(tq);
384
385 /* tq timeout expires every 1000ms if there are connections, so
386 * update the date cache at this point as well. */
387 update_date_cache(t);
388
389 if (!timeout_queue_empty(tq)) {
390 timeouts_add(t->wheel, &tq->timeout, 1000);
391 return true1;
392 }
393
394 timeouts_del(t->wheel, &tq->timeout);
395 }
396
397 return false0;
398}
399
400static int
401turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
402{
403 timeout_t wheel_timeout;
404 struct timespec now;
405
406 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0))
)
407 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 407, __FUNCTION__, "Could not get monotonic time")
;
408
409 timeouts_update(t->wheel,
410 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
411
412 wheel_timeout = timeouts_timeout(t->wheel);
413 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
414 goto infinite_timeout;
415
416 if (wheel_timeout == 0) {
417 if (!process_pending_timers(tq, t, epoll_fd))
418 goto infinite_timeout;
419
420 wheel_timeout = timeouts_timeout(t->wheel);
421 if (wheel_timeout == 0)
422 goto infinite_timeout;
423 }
424
425 return (int)wheel_timeout;
426
427infinite_timeout:
428 return -1;
429}
430
431static void *thread_io_loop(void *data)
432{
433 struct lwan_thread *t = data;
434 int epoll_fd = t->epoll_fd;
435 const int read_pipe_fd = t->pipe_fd[0];
436 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id8
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id9 = (1024); lwan_tmp_id8 > lwan_tmp_id9 ?
lwan_tmp_id9 : lwan_tmp_id8; })
;
437 struct lwan *lwan = t->lwan;
438 struct epoll_event *events;
439 struct coro_switcher switcher;
440 struct timeout_queue tq;
441
442 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 443, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
443 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 443, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
;
444 lwan_set_thread_name("worker");
445
446 events = calloc((size_t)max_events, sizeof(*events));
447 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
448 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"
, 448, __FUNCTION__, "Could not allocate memory for events")
;
449
450 update_date_cache(t);
451
452 timeout_queue_init(&tq, lwan);
453
454 pthread_barrier_wait(&lwan->thread.barrier);
455
456 for (;;) {
457 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
458 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
459
460 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
461 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
462 break;
463 continue;
464 }
465
466 for (struct epoll_event *event = events; n_fds--; event++) {
467 struct lwan_connection *conn;
468
469 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
470 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
471 epoll_fd);
472 continue;
473 }
474
475 conn = event->data.ptr;
476
477 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))
) {
478 timeout_queue_expire(&tq, conn);
479 continue;
480 }
481
482 resume_coro(&tq, conn, epoll_fd);
483 timeout_queue_move_to_last(&tq, conn);
484 }
485 }
486
487 pthread_barrier_wait(&lwan->thread.barrier);
488
489 timeout_queue_expire_all(&tq);
490 free(events);
491
492 return NULL((void*)0);
493}
494
495static void create_thread(struct lwan *l, struct lwan_thread *thread,
496 const size_t n_queue_fds)
497{
498 int ignore;
499 pthread_attr_t attr;
500
501 memset(thread, 0, sizeof(*thread));
502 thread->lwan = l;
503
504 thread->wheel = timeouts_open(&ignore);
505 if (!thread->wheel)
506 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 506, __FUNCTION__, "Could not create timer wheel")
;
507
508 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
509 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 509, __FUNCTION__, "epoll_create")
;
510
511 if (pthread_attr_init(&attr))
512 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 512, __FUNCTION__, "pthread_attr_init")
;
513
514 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
515 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 515, __FUNCTION__, "pthread_attr_setscope")
;
516
517 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
518 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 518, __FUNCTION__, "pthread_attr_setdetachstate")
;
519
520#if defined(HAVE_EVENTFD)
521 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
522 if (efd < 0)
523 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 523, __FUNCTION__, "eventfd")
;
524
525 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
526#else
527 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
528 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 528, __FUNCTION__, "pipe")
;
529#endif
530
531 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
532 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
533 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 533, __FUNCTION__, "epoll_ctl")
;
534
535 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
536 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 536, __FUNCTION__, "pthread_create")
;
537
538 if (pthread_attr_destroy(&attr))
539 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 539, __FUNCTION__, "pthread_attr_destroy")
;
540
541 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
542 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 543, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
543 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 543, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
;
544 }
545}
546
547void lwan_thread_nudge(struct lwan_thread *t)
548{
549 uint64_t event = 1;
550
551 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0))
)
552 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 552, __FUNCTION__, "write")
;
553}
554
555void lwan_thread_add_client(struct lwan_thread *t, int fd)
556{
557 for (int i = 0; i < 10; i++) {
558 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
559
560 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
561 return;
562
563 /* Queue is full; nudge the thread to consume it. */
564 lwan_thread_nudge(t);
565 }
566
567 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 567, __FUNCTION__, "Dropping connection %d", fd)
;
568 /* FIXME: send "busy" response now, even without receiving request? */
569 close(fd);
570}
571
572#if defined(__linux__1) && defined(__x86_64__1)
573static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
574{
575 char path[PATH_MAX4096];
576
577 for (unsigned int i = 0; i < l->n_cpus; i++) {
578 FILE *sib;
579 uint32_t id, sibling;
580 char separator;
581
582 snprintf(path, sizeof(path),
583 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
584 i);
585
586 sib = fopen(path, "re");
587 if (!sib) {
588 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"
, 589, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
589 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 589, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
;
590 return false0;
591 }
592
593 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
594 case 2: /* No SMT */
595 siblings[i] = id;
596 break;
597 case 3: /* SMT */
598 if (!(separator == ',' || separator == '-')) {
599 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"
, 599, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
)
;
600 __builtin_unreachable();
601 }
602
603 siblings[i] = sibling;
604 break;
605 default:
606 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 606, __FUNCTION__, "%s has invalid format", path)
;
607 __builtin_unreachable();
608 }
609
610
611 fclose(sib);
612 }
613
614 return true1;
615}
616
617static void
618siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
619{
620 int *seen = alloca(l->n_cpus * sizeof(int))__builtin_alloca (l->n_cpus * sizeof(int));
621 int n_schedtbl = 0;
622
623 for (uint32_t i = 0; i < l->n_cpus; i++)
624 seen[i] = -1;
625
626 for (uint32_t i = 0; i < l->n_cpus; i++) {
627 if (seen[siblings[i]] < 0) {
628 seen[siblings[i]] = (int)i;
629 } else {
630 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
631 schedtbl[n_schedtbl++] = i;
632 }
633 }
634
635 if (!n_schedtbl)
636 memcpy(schedtbl, seen, l->n_cpus * sizeof(int));
637}
638
639static void
640topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
641{
642 uint32_t *siblings = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
643
644 if (!read_cpu_topology(l, siblings)) {
11
Assuming the condition is true
12
Taking true branch
645 for (uint32_t i = 0; i < n_threads; i++)
13
Assuming 'i' is >= 'n_threads'
14
Loop condition is false. Execution continues on line 645
646 schedtbl[i] = (i / 2) % l->thread.count;
647 } else {
648 uint32_t *affinity = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
649
650 siblings_to_schedtbl(l, siblings, affinity);
651
652 for (uint32_t i = 0; i < n_threads; i++)
653 schedtbl[i] = affinity[i % l->n_cpus];
654 }
655}
656
657static void
658adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
659{
660 for (uint32_t i = 0; i < l->thread.count; i++) {
17
Assuming 'i' is < field 'count'
18
Loop condition is true. Entering loop body
661 cpu_set_t set;
662
663 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0)
;
19
Loop condition is false. Exiting loop
664 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; }))
;
20
Assigned value is garbage or undefined
665
666 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
667 &set))
668 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"
, 668, __FUNCTION__, "Could not set affinity for thread %d", i
)
;
669 }
670}
671#elif defined(__x86_64__1)
672static void
673topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
674{
675 for (uint32_t i = 0; i < n_threads; i++)
676 schedtbl[i] = (i / 2) % l->thread.count;
677}
678
679static void
680adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
681{
682}
683#endif
684
685void lwan_thread_init(struct lwan *l)
686{
687 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
2
Taking false branch
688 (unsigned)l->thread.count + 1))
689 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 689, __FUNCTION__, "Could not create barrier")
;
690
691 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 691, __FUNCTION__, "Initializing threads")
;
692
693 l->thread.threads =
694 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
695 if (!l->thread.threads)
3
Assuming field 'threads' is non-null
4
Taking false branch
696 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"
, 696, __FUNCTION__, "Could not allocate memory for threads")
;
697
698 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_id10 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id11 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id10 > lwan_tmp_id11 ? lwan_tmp_id11 : lwan_tmp_id10
; })
5
Assuming 'lwan_tmp_id2' is <= 'lwan_tmp_id3'
6
'?' condition is false
699 (size_t)(2 * lwan_socket_get_backlog_size()))({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id10 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id11 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id10 > lwan_tmp_id11 ? lwan_tmp_id11 : lwan_tmp_id10
; })
;
700 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"
, 700, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds)
;
701 for (unsigned int i = 0; i < l->thread.
6.1
'i' is < field 'count'
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 704
702 create_thread(l, &l->thread.threads[i], n_queue_fds);
703
704 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
705#ifdef __x86_64__1
706 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; })]
707 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })]
;
708 /*
709 * Pre-schedule each file descriptor, to reduce some operations in the
710 * fast path.
711 *
712 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
713 * them can fill up a cache line. Assume siblings share cache lines and
714 * use the CPU topology to group two connections per cache line in such
715 * a way that false sharing is avoided.
716 */
717 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
718 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
719
720 topology_to_schedtbl(l, schedtbl, n_threads);
10
Calling 'topology_to_schedtbl'
15
Returning from 'topology_to_schedtbl'
721
722 n_threads--; /* Transform count into mask for AND below */
723 adjust_threads_affinity(l, schedtbl, n_threads);
16
Calling 'adjust_threads_affinity'
724 for (unsigned int i = 0; i < total_conns; i++)
725 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
726#else
727 for (unsigned int i = 0; i < total_conns; i++)
728 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
729#endif
730
731 pthread_barrier_wait(&l->thread.barrier);
732
733 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"
, 733, __FUNCTION__, "Worker threads created and ready to serve"
)
;
734}
735
736void lwan_thread_shutdown(struct lwan *l)
737{
738 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 738, __FUNCTION__, "Shutting down threads")
;
739
740 for (unsigned int i = 0; i < l->thread.count; i++) {
741 struct lwan_thread *t = &l->thread.threads[i];
742
743 close(t->epoll_fd);
744 lwan_thread_nudge(t);
745 }
746
747 pthread_barrier_wait(&l->thread.barrier);
748 pthread_barrier_destroy(&l->thread.barrier);
749
750 for (unsigned int i = 0; i < l->thread.count; i++) {
751 struct lwan_thread *t = &l->thread.threads[i];
752
753 close(t->pipe_fd[0]);
754#if !defined(HAVE_EVENTFD)
755 close(t->pipe_fd[1]);
756#endif
757
758 pthread_join(l->thread.threads[i].self, NULL((void*)0));
759 spsc_queue_free(&t->pending_fds);
760 timeouts_close(t->wheel);
761 }
762
763 free(l->thread.threads);
764}