Bug Summary

File:lwan-thread.c
Warning:line 722, 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/2020-05-22-012346-168569-1 -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 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
212 [CONN_CORO_YIELD] = ~0,
213
214 [CONN_CORO_WANT_READ_WRITE] = ~0,
215 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
216 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
217
218 [CONN_CORO_SUSPEND_TIMER] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_ASYNC_AWAIT),
219 [CONN_CORO_SUSPEND_ASYNC_AWAIT] = ~(CONN_EVENTS_READ_WRITE | CONN_SUSPENDED_TIMER),
220 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
221 };
222 enum lwan_connection_flags prev_flags = conn->flags;
223
224 conn->flags |= or_mask[yield_result];
225 conn->flags &= and_mask[yield_result];
226
227 if (conn->flags == prev_flags)
228 return;
229
230 struct epoll_event event = {
231 .events = conn_flags_to_epoll_events(conn->flags),
232 .data.ptr = conn,
233 };
234
235 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0))
)
236 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 236, __FUNCTION__, "epoll_ctl")
;
237}
238
239static enum lwan_connection_coro_yield
240resume_async(enum lwan_connection_coro_yield yield_result,
241 int64_t from_coro,
242 struct lwan_connection *conn,
243 int epoll_fd)
244{
245 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"
, 246, __extension__ __PRETTY_FUNCTION__); }))
246 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"
, 246, __extension__ __PRETTY_FUNCTION__); }))
;
247
248 static const enum lwan_connection_flags to_connection_flags[] = {
249 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_ASYNC_READ,
250 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_ASYNC_WRITE,
251 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_ASYNC_READ_WRITE,
252 };
253 struct epoll_event event = {
254 .events = conn_flags_to_epoll_events(to_connection_flags[yield_result]),
255 .data.ptr = conn,
256 };
257 int await_fd = (int)((uint64_t)from_coro >> 32);
258
259 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"
, 259, __extension__ __PRETTY_FUNCTION__); }))
;
260 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"
, 260, __extension__ __PRETTY_FUNCTION__); }))
;
261
262 /* FIXME: maybe store the state in the lwan_connection array to avoid trying
263 * this syscall twice the first time? */
264 if (epoll_ctl(epoll_fd, EPOLL_CTL_MOD3, await_fd, &event) < 0) {
265 if (UNLIKELY(errno != ENOENT)__builtin_expect((((*__errno_location ()) != 2)), (0)))
266 return CONN_CORO_ABORT;
267 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_ADD, await_fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 1, await_fd, &event
) < 0)), (0))
)
268 return CONN_CORO_ABORT;
269 }
270
271 return CONN_CORO_SUSPEND_ASYNC_AWAIT;
272}
273
274static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
275 struct lwan_connection *conn,
276 int epoll_fd)
277{
278 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"
, 278, __extension__ __PRETTY_FUNCTION__); }))
;
279
280 int64_t from_coro = coro_resume(conn->coro);
281 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
282
283 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
284 yield_result = resume_async(yield_result, from_coro, conn, epoll_fd);
285
286 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
287 return timeout_queue_expire(tq, conn);
288
289 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
290 epoll_fd, yield_result);
291}
292
293static void update_date_cache(struct lwan_thread *thread)
294{
295 time_t now = time(NULL((void*)0));
296
297 lwan_format_rfc_time(now, thread->date.date);
298 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
299 thread->date.expires);
300}
301
302static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
303 struct coro_switcher *switcher,
304 struct timeout_queue *tq)
305{
306 struct lwan_thread *t = conn->thread;
307
308 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"
, 308, __extension__ __PRETTY_FUNCTION__); }))
;
309 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"
, 309, __extension__ __PRETTY_FUNCTION__); }))
;
310 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"
, 310, __extension__ __PRETTY_FUNCTION__); }))
;
311 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"
, 312, __extension__ __PRETTY_FUNCTION__); }))
312 (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"
, 312, __extension__ __PRETTY_FUNCTION__); }))
;
313
314 *conn = (struct lwan_connection) {
315 .coro = coro_new(switcher, process_request_coro, conn),
316 .flags = CONN_EVENTS_READ,
317 .time_to_expire = tq->current_time + tq->move_to_last_bump,
318 .thread = t,
319 };
320 if (UNLIKELY(!conn->coro)__builtin_expect(((!conn->coro)), (0))) {
321 conn->flags = 0;
322 lwan_status_error("Could not create coroutine")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 322, __FUNCTION__, "Could not create coroutine")
;
323 return;
324 }
325
326 timeout_queue_insert(tq, conn);
327}
328
329static void accept_nudge(int pipe_fd,
330 struct lwan_thread *t,
331 struct lwan_connection *conns,
332 struct timeout_queue *tq,
333 struct coro_switcher *switcher,
334 int epoll_fd)
335{
336 uint64_t event;
337 int new_fd;
338
339 /* Errors are ignored here as pipe_fd serves just as a way to wake the
340 * thread from epoll_wait(). It's fine to consume the queue at this
341 * point, regardless of the error type. */
342 (void)read(pipe_fd, &event, sizeof(event));
343
344 while (spsc_queue_pop(&t->pending_fds, &new_fd)) {
345 struct lwan_connection *conn = &conns[new_fd];
346 struct epoll_event ev = {
347 .data.ptr = conn,
348 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
349 };
350
351 if (LIKELY(!epoll_ctl(epoll_fd, EPOLL_CTL_ADD, new_fd, &ev))__builtin_expect((!!(!epoll_ctl(epoll_fd, 1, new_fd, &ev)
)), (1))
)
352 spawn_coro(conn, switcher, tq);
353 }
354
355 timeouts_add(t->wheel, &tq->timeout, 1000);
356}
357
358static bool_Bool process_pending_timers(struct timeout_queue *tq,
359 struct lwan_thread *t,
360 int epoll_fd)
361{
362 struct timeout *timeout;
363 bool_Bool should_expire_timers = false0;
364
365 while ((timeout = timeouts_get(t->wheel))) {
366 struct lwan_request *request;
367
368 if (timeout == &tq->timeout) {
369 should_expire_timers = true1;
370 continue;
371 }
372
373 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))
;
374
375 update_epoll_flags(request->fd, request->conn, epoll_fd,
376 CONN_CORO_RESUME);
377 }
378
379 if (should_expire_timers) {
380 timeout_queue_expire_waiting(tq);
381
382 /* tq timeout expires every 1000ms if there are connections, so
383 * update the date cache at this point as well. */
384 update_date_cache(t);
385
386 if (!timeout_queue_empty(tq)) {
387 timeouts_add(t->wheel, &tq->timeout, 1000);
388 return true1;
389 }
390
391 timeouts_del(t->wheel, &tq->timeout);
392 }
393
394 return false0;
395}
396
397static int
398turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
399{
400 timeout_t wheel_timeout;
401 struct timespec now;
402
403 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0))
)
404 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 404, __FUNCTION__, "Could not get monotonic time")
;
405
406 timeouts_update(t->wheel,
407 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
408
409 wheel_timeout = timeouts_timeout(t->wheel);
410 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
411 goto infinite_timeout;
412
413 if (wheel_timeout == 0) {
414 if (!process_pending_timers(tq, t, epoll_fd))
415 goto infinite_timeout;
416
417 wheel_timeout = timeouts_timeout(t->wheel);
418 if (wheel_timeout == 0)
419 goto infinite_timeout;
420 }
421
422 return (int)wheel_timeout;
423
424infinite_timeout:
425 return -1;
426}
427
428static void *thread_io_loop(void *data)
429{
430 struct lwan_thread *t = data;
431 int epoll_fd = t->epoll_fd;
432 const int read_pipe_fd = t->pipe_fd[0];
433 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id12
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id13 = (1024); lwan_tmp_id12 > lwan_tmp_id13
? lwan_tmp_id13 : lwan_tmp_id12; })
;
434 struct lwan *lwan = t->lwan;
435 struct epoll_event *events;
436 struct coro_switcher switcher;
437 struct timeout_queue tq;
438
439 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 440, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
440 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 440, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
;
441 lwan_set_thread_name("worker");
442
443 events = calloc((size_t)max_events, sizeof(*events));
444 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
445 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"
, 445, __FUNCTION__, "Could not allocate memory for events")
;
446
447 update_date_cache(t);
448
449 timeout_queue_init(&tq, lwan);
450
451 pthread_barrier_wait(&lwan->thread.barrier);
452
453 for (;;) {
454 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
455 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
456
457 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
458 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
459 break;
460 continue;
461 }
462
463 for (struct epoll_event *event = events; n_fds--; event++) {
464 struct lwan_connection *conn;
465
466 if (UNLIKELY(!event->data.ptr)__builtin_expect(((!event->data.ptr)), (0))) {
467 accept_nudge(read_pipe_fd, t, lwan->conns, &tq, &switcher,
468 epoll_fd);
469 continue;
470 }
471
472 conn = event->data.ptr;
473
474 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))
) {
475 timeout_queue_expire(&tq, conn);
476 continue;
477 }
478
479 resume_coro(&tq, conn, epoll_fd);
480 timeout_queue_move_to_last(&tq, conn);
481 }
482 }
483
484 pthread_barrier_wait(&lwan->thread.barrier);
485
486 timeout_queue_expire_all(&tq);
487 free(events);
488
489 return NULL((void*)0);
490}
491
492static void create_thread(struct lwan *l, struct lwan_thread *thread,
493 const size_t n_queue_fds)
494{
495 int ignore;
496 pthread_attr_t attr;
497
498 memset(thread, 0, sizeof(*thread));
499 thread->lwan = l;
500
501 thread->wheel = timeouts_open(&ignore);
502 if (!thread->wheel)
503 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 503, __FUNCTION__, "Could not create timer wheel")
;
504
505 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
506 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 506, __FUNCTION__, "epoll_create")
;
507
508 if (pthread_attr_init(&attr))
509 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 509, __FUNCTION__, "pthread_attr_init")
;
510
511 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
512 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 512, __FUNCTION__, "pthread_attr_setscope")
;
513
514 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
515 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 515, __FUNCTION__, "pthread_attr_setdetachstate")
;
516
517#if defined(HAVE_EVENTFD)
518 int efd = eventfd(0, EFD_NONBLOCKEFD_NONBLOCK | EFD_SEMAPHOREEFD_SEMAPHORE | EFD_CLOEXECEFD_CLOEXEC);
519 if (efd < 0)
520 lwan_status_critical_perror("eventfd")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 520, __FUNCTION__, "eventfd")
;
521
522 thread->pipe_fd[0] = thread->pipe_fd[1] = efd;
523#else
524 if (pipe2(thread->pipe_fd, O_NONBLOCK04000 | O_CLOEXEC02000000) < 0)
525 lwan_status_critical_perror("pipe")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 525, __FUNCTION__, "pipe")
;
526#endif
527
528 struct epoll_event event = { .events = EPOLLINEPOLLIN, .data.ptr = NULL((void*)0) };
529 if (epoll_ctl(thread->epoll_fd, EPOLL_CTL_ADD1, thread->pipe_fd[0], &event) < 0)
530 lwan_status_critical_perror("epoll_ctl")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 530, __FUNCTION__, "epoll_ctl")
;
531
532 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
533 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 533, __FUNCTION__, "pthread_create")
;
534
535 if (pthread_attr_destroy(&attr))
536 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 536, __FUNCTION__, "pthread_attr_destroy")
;
537
538 if (spsc_queue_init(&thread->pending_fds, n_queue_fds) < 0) {
539 lwan_status_critical("Could not initialize pending fd "lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 540, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
540 "queue width %zu elements", n_queue_fds)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 540, __FUNCTION__, "Could not initialize pending fd " "queue width %zu elements"
, n_queue_fds)
;
541 }
542}
543
544void lwan_thread_nudge(struct lwan_thread *t)
545{
546 uint64_t event = 1;
547
548 if (UNLIKELY(write(t->pipe_fd[1], &event, sizeof(event)) < 0)__builtin_expect(((write(t->pipe_fd[1], &event, sizeof
(event)) < 0)), (0))
)
549 lwan_status_perror("write")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 549, __FUNCTION__, "write")
;
550}
551
552void lwan_thread_add_client(struct lwan_thread *t, int fd)
553{
554 for (int i = 0; i < 10; i++) {
555 bool_Bool pushed = spsc_queue_push(&t->pending_fds, fd);
556
557 if (LIKELY(pushed)__builtin_expect((!!(pushed)), (1)))
558 return;
559
560 /* Queue is full; nudge the thread to consume it. */
561 lwan_thread_nudge(t);
562 }
563
564 lwan_status_error("Dropping connection %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 564, __FUNCTION__, "Dropping connection %d", fd)
;
565 /* FIXME: send "busy" response now, even without receiving request? */
566 close(fd);
567}
568
569#if defined(__linux__1) && defined(__x86_64__1)
570static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
571{
572 char path[PATH_MAX4096];
573
574 for (unsigned int i = 0; i < l->n_cpus; i++) {
575 FILE *sib;
576 uint32_t id, sibling;
577 char separator;
578
579 snprintf(path, sizeof(path),
580 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
581 i);
582
583 sib = fopen(path, "re");
584 if (!sib) {
585 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"
, 586, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
586 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 586, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
;
587 return false0;
588 }
589
590 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
591 case 2: /* No SMT */
592 siblings[i] = id;
593 break;
594 case 3: /* SMT */
595 if (!(separator == ',' || separator == '-')) {
596 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"
, 596, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
)
;
597 __builtin_unreachable();
598 }
599
600 siblings[i] = sibling;
601 break;
602 default:
603 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 603, __FUNCTION__, "%s has invalid format", path)
;
604 __builtin_unreachable();
605 }
606
607
608 fclose(sib);
609 }
610
611 return true1;
612}
613
614static void
615siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
616{
617 int *seen = alloca(l->n_cpus * sizeof(int))__builtin_alloca (l->n_cpus * sizeof(int));
618 int n_schedtbl = 0;
619
620 for (uint32_t i = 0; i < l->n_cpus; i++)
621 seen[i] = -1;
622
623 for (uint32_t i = 0; i < l->n_cpus; i++) {
624 if (seen[siblings[i]] < 0) {
625 seen[siblings[i]] = (int)i;
626 } else {
627 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
628 schedtbl[n_schedtbl++] = i;
629 }
630 }
631
632 if (!n_schedtbl)
633 memcpy(schedtbl, seen, l->n_cpus * sizeof(int));
634}
635
636static void
637topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
638{
639 uint32_t *siblings = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
640
641 if (!read_cpu_topology(l, siblings)) {
11
Assuming the condition is true
12
Taking true branch
642 for (uint32_t i = 0; i < n_threads; i++)
13
Assuming 'i' is >= 'n_threads'
14
Loop condition is false. Execution continues on line 642
643 schedtbl[i] = (i / 2) % l->thread.count;
644 } else {
645 uint32_t *affinity = alloca(l->n_cpus * sizeof(uint32_t))__builtin_alloca (l->n_cpus * sizeof(uint32_t));
646
647 siblings_to_schedtbl(l, siblings, affinity);
648
649 for (uint32_t i = 0; i < n_threads; i++)
650 schedtbl[i] = affinity[i % l->n_cpus];
651 }
652}
653
654static void
655adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
656{
657 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 657
658 cpu_set_t set;
659
660 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0)
;
661 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; }))
;
662
663 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
664 &set))
665 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"
, 665, __FUNCTION__, "Could not set affinity for thread %d", i
)
;
666 }
667}
668#elif defined(__x86_64__1)
669static void
670topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
671{
672 for (uint32_t i = 0; i < n_threads; i++)
673 schedtbl[i] = (i / 2) % l->thread.count;
674}
675
676static void
677adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
678{
679}
680#endif
681
682void lwan_thread_init(struct lwan *l)
683{
684 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
2
Taking false branch
685 (unsigned)l->thread.count + 1))
686 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 686, __FUNCTION__, "Could not create barrier")
;
687
688 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 688, __FUNCTION__, "Initializing threads")
;
689
690 l->thread.threads =
691 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
692 if (!l->thread.threads)
3
Assuming field 'threads' is non-null
4
Taking false branch
693 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"
, 693, __FUNCTION__, "Could not allocate memory for threads")
;
694
695 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_id14 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id15 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id14 > lwan_tmp_id15 ? lwan_tmp_id15 : lwan_tmp_id14
; })
5
Assuming 'lwan_tmp_id2' is <= 'lwan_tmp_id3'
6
'?' condition is false
696 (size_t)(2 * lwan_socket_get_backlog_size()))({ const __typeof__((l->thread.max_fd / l->thread.count
) + 0) lwan_tmp_id14 = (l->thread.max_fd / l->thread.count
); const __typeof__(((size_t)(2 * lwan_socket_get_backlog_size
())) + 0) lwan_tmp_id15 = ((size_t)(2 * lwan_socket_get_backlog_size
())); lwan_tmp_id14 > lwan_tmp_id15 ? lwan_tmp_id15 : lwan_tmp_id14
; })
;
697 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"
, 697, __FUNCTION__, "Pending client file descriptor queue has %zu items"
, n_queue_fds)
;
698 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 701
699 create_thread(l, &l->thread.threads[i], n_queue_fds);
700
701 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
702#ifdef __x86_64__1
703 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; })]
704 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })]
;
705 /*
706 * Pre-schedule each file descriptor, to reduce some operations in the
707 * fast path.
708 *
709 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
710 * them can fill up a cache line. Assume siblings share cache lines and
711 * use the CPU topology to group two connections per cache line in such
712 * a way that false sharing is avoided.
713 */
714 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
715 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
716
717 topology_to_schedtbl(l, schedtbl, n_threads);
10
Calling 'topology_to_schedtbl'
15
Returning from 'topology_to_schedtbl'
718
719 n_threads--; /* Transform count into mask for AND below */
720 adjust_threads_affinity(l, schedtbl, n_threads);
16
Calling 'adjust_threads_affinity'
19
Returning from 'adjust_threads_affinity'
721 for (unsigned int i = 0; i < total_conns; i++)
20
Assuming 'i' is < 'total_conns'
21
Loop condition is true. Entering loop body
722 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
22
Array subscript is undefined
723#else
724 for (unsigned int i = 0; i < total_conns; i++)
725 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
726#endif
727
728 pthread_barrier_wait(&l->thread.barrier);
729
730 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"
, 730, __FUNCTION__, "Worker threads created and ready to serve"
)
;
731}
732
733void lwan_thread_shutdown(struct lwan *l)
734{
735 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 735, __FUNCTION__, "Shutting down threads")
;
736
737 for (unsigned int i = 0; i < l->thread.count; i++) {
738 struct lwan_thread *t = &l->thread.threads[i];
739
740 close(t->epoll_fd);
741 lwan_thread_nudge(t);
742 }
743
744 pthread_barrier_wait(&l->thread.barrier);
745 pthread_barrier_destroy(&l->thread.barrier);
746
747 for (unsigned int i = 0; i < l->thread.count; i++) {
748 struct lwan_thread *t = &l->thread.threads[i];
749
750 close(t->pipe_fd[0]);
751#if !defined(HAVE_EVENTFD)
752 close(t->pipe_fd[1]);
753#endif
754
755 pthread_join(l->thread.threads[i].self, NULL((void*)0));
756 spsc_queue_free(&t->pending_fds);
757 timeouts_close(t->wheel);
758 }
759
760 free(l->thread.threads);
761}