Bug Summary

File:lwan-thread.c
Warning:line 700, column 9
Assigned value is garbage or undefined

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name lwan-thread.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -mframe-pointer=all -fmath-errno -fno-rounding-math -mconstructor-aliases -fno-plt -munwind-tables -target-cpu x86-64 -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/clang/11.1.0 -include /home/buildbot/lwan-worker/clang-analyze/build/lwan-build-config.h -D _FILE_OFFSET_BITS=64 -D _TIME_BITS=64 -I /home/buildbot/lwan-worker/clang-analyze/build/src/lib/missing -I /usr/include/luajit-2.0 -I /usr/include/valgrind -I /home/buildbot/lwan-worker/clang-analyze/build/src/lib -I /home/buildbot/lwan-worker/clang-analyze/build -internal-isystem /usr/local/include -internal-isystem /usr/lib/clang/11.1.0/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -Wno-unused-parameter -Wno-free-nonheap-object -std=gnu99 -fdebug-compilation-dir /home/buildbot/lwan-worker/clang-analyze/build/src/lib -ferror-limit 19 -stack-protector 2 -fgnuc-version=4.2.1 -analyzer-output=html -faddrsig -o /home/buildbot/lwan-worker/clang-analyze/CLANG/2021-05-10-041938-4057710-1 -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#include "lwan-private.h"
35#include "lwan-tq.h"
36#include "list.h"
37
38static void lwan_strbuf_free_defer(void *data)
39{
40 lwan_strbuf_free((struct lwan_strbuf *)data);
41}
42
43static void graceful_close(struct lwan *l,
44 struct lwan_connection *conn,
45 char buffer[static DEFAULT_BUFFER_SIZE4096])
46{
47 int fd = lwan_connection_get_fd(l, conn);
48
49 while (TIOCOUTQ0x5411) {
50 /* This ioctl isn't probably doing what it says on the tin; the details
51 * are subtle, but it seems to do the trick to allow gracefully closing
52 * the connection in some cases with minimal system calls. */
53 int bytes_waiting;
54 int r = ioctl(fd, TIOCOUTQ0x5411, &bytes_waiting);
55
56 if (!r && !bytes_waiting) /* See note about close(2) below. */
57 return;
58 if (r < 0 && errno(*__errno_location ()) == EINTR4)
59 continue;
60
61 break;
62 }
63
64 if (UNLIKELY(shutdown(fd, SHUT_WR) < 0)__builtin_expect(((shutdown(fd, SHUT_WR) < 0)), (0))) {
65 if (UNLIKELY(errno == ENOTCONN)__builtin_expect((((*__errno_location ()) == 107)), (0)))
66 return;
67 }
68
69 for (int tries = 0; tries < 20; tries++) {
70 ssize_t r = read(fd, buffer, DEFAULT_BUFFER_SIZE4096);
71
72 if (!r)
73 break;
74
75 if (r < 0) {
76 switch (errno(*__errno_location ())) {
77 case EAGAIN11:
78 break;
79 case EINTR4:
80 continue;
81 default:
82 return;
83 }
84 }
85
86 coro_yield(conn->coro, CONN_CORO_WANT_READ);
87 }
88
89 /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
90}
91
92__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
93 void *data)
94{
95 /* NOTE: This function should not return; coro_yield should be used
96 * instead. This ensures the storage for `strbuf` is alive when the
97 * coroutine ends and lwan_strbuf_free() is called. */
98 struct lwan_connection *conn = data;
99 struct lwan *lwan = conn->thread->lwan;
100 int fd = lwan_connection_get_fd(lwan, conn);
101 enum lwan_request_flags flags = lwan->config.request_flags;
102 struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
103 char request_buffer[DEFAULT_BUFFER_SIZE4096];
104 struct lwan_value buffer = {.value = request_buffer, .len = 0};
105 char *next_request = NULL((void*)0);
106 char *header_start[N_HEADER_START64];
107 struct lwan_proxy proxy;
108 const int error_when_n_packets = lwan_calculate_n_packets(DEFAULT_BUFFER_SIZE4096);
109
110 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
111
112 const size_t init_gen = 1; /* 1 call to coro_defer() */
113 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"
, 113, __extension__ __PRETTY_FUNCTION__); }))
;
114
115 while (true1) {
116 struct lwan_request_parser_helper helper = {
117 .buffer = &buffer,
118 .next_request = next_request,
119 .error_when_n_packets = error_when_n_packets,
120 .header_start = header_start,
121 };
122 struct lwan_request request = {.conn = conn,
123 .global_response_headers = &lwan->headers,
124 .fd = fd,
125 .response = {.buffer = &strbuf},
126 .flags = flags,
127 .proxy = &proxy,
128 .helper = &helper};
129
130 lwan_process_request(lwan, &request);
131
132 /* Run the deferred instructions now (except those used to initialize
133 * the coroutine), so that if the connection is gracefully closed,
134 * the storage for ``helper'' is still there. */
135 coro_deferred_run(coro, init_gen);
136
137 if (UNLIKELY(!(conn->flags & CONN_IS_KEEP_ALIVE))__builtin_expect(((!(conn->flags & CONN_IS_KEEP_ALIVE)
)), (0))
) {
138 graceful_close(lwan, conn, request_buffer);
139 break;
140 }
141
142 if (next_request && *next_request) {
143 conn->flags |= CONN_CORK;
144
145 if (!(conn->flags & CONN_EVENTS_WRITE))
146 coro_yield(coro, CONN_CORO_WANT_WRITE);
147 } else {
148 conn->flags &= ~CONN_CORK;
149 coro_yield(coro, CONN_CORO_WANT_READ);
150 }
151
152 /* Ensure string buffer is reset between requests, and that the backing
153 * store isn't over 2KB. */
154 lwan_strbuf_reset_trim(&strbuf, 2048);
155
156 /* Only allow flags from config. */
157 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
158 next_request = helper.next_request;
159 }
160
161 coro_yield(coro, CONN_CORO_ABORT);
162 __builtin_unreachable();
163}
164
165static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
166conn_flags_to_epoll_events(enum lwan_connection_flags flags)
167{
168 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
169 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
170 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
171 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
172 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
173 };
174
175 return map[flags & CONN_EVENTS_MASK];
176}
177
178static void update_epoll_flags(int fd,
179 struct lwan_connection *conn,
180 int epoll_fd,
181 enum lwan_connection_coro_yield yield_result)
182{
183 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
184 [CONN_CORO_YIELD] = 0,
185
186 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
187 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
188 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
189
190 /* While the coro is suspended, we're not interested in either EPOLLIN
191 * or EPOLLOUT events. We still want to track this fd in epoll, though,
192 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
193 * are set. */
194 [CONN_CORO_SUSPEND] = CONN_SUSPENDED,
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] = ~CONN_EVENTS_READ_WRITE,
213 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
214 };
215 enum lwan_connection_flags prev_flags = conn->flags;
216
217 conn->flags |= or_mask[yield_result];
218 conn->flags &= and_mask[yield_result];
219
220 if (conn->flags == prev_flags)
221 return;
222
223 struct epoll_event event = {
224 .events = conn_flags_to_epoll_events(conn->flags),
225 .data.ptr = conn,
226 };
227
228 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0))
)
229 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 229, __FUNCTION__, "epoll_ctl")
;
230}
231
232static void clear_async_await_flag(void *data)
233{
234 struct lwan_connection *async_fd_conn = data;
235
236 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
237}
238
239static enum lwan_connection_coro_yield
240resume_async(struct timeout_queue *tq,
241 enum lwan_connection_coro_yield yield_result,
242 int64_t from_coro,
243 struct lwan_connection *conn,
244 int epoll_fd)
245{
246 static const enum lwan_connection_flags to_connection_flags[] = {
247 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
248 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
249 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
250 };
251 int await_fd = (int)((uint64_t)from_coro >> 32);
252 enum lwan_connection_flags flags;
253 int op;
254
255 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"
, 255, __extension__ __PRETTY_FUNCTION__); }))
;
256 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"
, 257, __extension__ __PRETTY_FUNCTION__); }))
257 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"
, 257, __extension__ __PRETTY_FUNCTION__); }))
;
258
259 flags = to_connection_flags[yield_result];
260
261 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
262 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))
) {
263 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1))
)
264 return CONN_CORO_SUSPEND;
265
266 op = EPOLL_CTL_MOD3;
267 } else {
268 op = EPOLL_CTL_ADD1;
269 flags |= CONN_ASYNC_AWAIT;
270 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
271 }
272
273 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
274 .data.ptr = conn};
275 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))
) {
276 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
277 await_fd_conn->flags |= flags;
278 return CONN_CORO_SUSPEND;
279 }
280
281 return CONN_CORO_ABORT;
282}
283
284static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
285 struct lwan_connection *conn,
286 int epoll_fd)
287{
288 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"
, 288, __extension__ __PRETTY_FUNCTION__); }))
;
289
290 int64_t from_coro = coro_resume(conn->coro);
291 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
292
293 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
294 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
295
296 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
297 return timeout_queue_expire(tq, conn);
298
299 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
300 epoll_fd, yield_result);
301}
302
303static void update_date_cache(struct lwan_thread *thread)
304{
305 time_t now = time(NULL((void*)0));
306
307 lwan_format_rfc_time(now, thread->date.date);
308 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
309 thread->date.expires);
310}
311
312static ALWAYS_INLINEinline __attribute__((always_inline)) void spawn_coro(struct lwan_connection *conn,
313 struct coro_switcher *switcher,
314 struct timeout_queue *tq)
315{
316 struct lwan_thread *t = conn->thread;
317
318 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"
, 318, __extension__ __PRETTY_FUNCTION__); }))
;
319 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"
, 319, __extension__ __PRETTY_FUNCTION__); }))
;
320 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"
, 320, __extension__ __PRETTY_FUNCTION__); }))
;
321 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"
, 322, __extension__ __PRETTY_FUNCTION__); }))
322 (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"
, 322, __extension__ __PRETTY_FUNCTION__); }))
;
323
324 *conn = (struct lwan_connection) {
325 .coro = coro_new(switcher, process_request_coro, conn),
326 .flags = CONN_EVENTS_READ,
327 .time_to_expire = tq->current_time + tq->move_to_last_bump,
328 .thread = t,
329 };
330 if (LIKELY(conn->coro)__builtin_expect((!!(conn->coro)), (1))) {
331 timeout_queue_insert(tq, conn);
332 return;
333 }
334
335 /* FIXME: send a "busy" response to this client? we don't have a coroutine
336 * at this point, can't use lwan_send() here */
337 lwan_status_error("Could not create coroutine, dropping connection")lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 337, __FUNCTION__, "Could not create coroutine, dropping connection"
)
;
338
339 conn->flags = 0;
340
341 int fd = lwan_connection_get_fd(tq->lwan, conn);
342 shutdown(fd, SHUT_RDWRSHUT_RDWR);
343 close(fd);
344}
345
346static bool_Bool process_pending_timers(struct timeout_queue *tq,
347 struct lwan_thread *t,
348 int epoll_fd)
349{
350 struct timeout *timeout;
351 bool_Bool should_expire_timers = false0;
352
353 while ((timeout = timeouts_get(t->wheel))) {
354 struct lwan_request *request;
355
356 if (timeout == &tq->timeout) {
357 should_expire_timers = true1;
358 continue;
359 }
360
361 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))
;
362
363 update_epoll_flags(request->fd, request->conn, epoll_fd,
364 CONN_CORO_RESUME);
365 }
366
367 if (should_expire_timers) {
368 timeout_queue_expire_waiting(tq);
369
370 /* tq timeout expires every 1000ms if there are connections, so
371 * update the date cache at this point as well. */
372 update_date_cache(t);
373
374 if (!timeout_queue_empty(tq)) {
375 timeouts_add(t->wheel, &tq->timeout, 1000);
376 return true1;
377 }
378
379 timeouts_del(t->wheel, &tq->timeout);
380 }
381
382 return false0;
383}
384
385static int
386turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
387{
388 const int infinite_timeout = -1;
389 timeout_t wheel_timeout;
390 struct timespec now;
391
392 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0))
)
393 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 393, __FUNCTION__, "Could not get monotonic time")
;
394
395 timeouts_update(t->wheel,
396 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
397
398 /* Check if there's an expired timer. */
399 wheel_timeout = timeouts_timeout(t->wheel);
400 if (wheel_timeout > 0) {
401 return (int)wheel_timeout; /* No, but will soon. Wake us up in
402 wheel_timeout ms. */
403 }
404
405 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
406 return infinite_timeout; /* None found. */
407
408 if (!process_pending_timers(tq, t, epoll_fd))
409 return infinite_timeout; /* No more timers to process. */
410
411 /* After processing pending timers, determine when to wake up. */
412 return (int)timeouts_timeout(t->wheel);
413}
414
415enum herd_accept { HERD_MORE = 0, HERD_GONE = -1, HERD_SHUTDOWN = 1 };
416
417static ALWAYS_INLINEinline __attribute__((always_inline)) enum herd_accept
418accept_one(struct lwan *l, const struct lwan_thread *t)
419{
420 int fd = accept4(t->listen_fd, NULL((void*)0), NULL((void*)0), SOCK_NONBLOCKSOCK_NONBLOCK | SOCK_CLOEXECSOCK_CLOEXEC);
421
422 if (LIKELY(fd >= 0)__builtin_expect((!!(fd >= 0)), (1))) {
423 struct epoll_event ev = {
424 .data.ptr = &l->conns[fd],
425 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
426 };
427 epoll_ctl(t->epoll_fd, EPOLL_CTL_ADD1, fd, &ev);
428
429 return HERD_MORE;
430 }
431
432 switch (errno(*__errno_location ())) {
433 case EAGAIN11:
434 return HERD_GONE;
435
436 case EBADF9:
437 case ECONNABORTED103:
438 case EINVAL22:
439 lwan_status_info("Listening socket closed")lwan_status_info_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 439, __FUNCTION__, "Listening socket closed")
;
440 return HERD_SHUTDOWN;
441
442 default:
443 lwan_status_perror("accept")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 443, __FUNCTION__, "accept")
;
444 return HERD_MORE;
445 }
446}
447
448static bool_Bool try_accept_connections(const struct lwan_thread *t)
449{
450 struct lwan *lwan = t->lwan;
451 enum herd_accept ha;
452
453 while ((ha = accept_one(lwan, t)) == HERD_MORE) {
454 }
455
456 if (ha > HERD_MORE)
457 return false0;
458
459 return true1;
460}
461
462static int create_listen_socket(struct lwan_thread *t, bool_Bool print_listening_msg)
463{
464 int listen_fd;
465
466 listen_fd = lwan_create_listen_socket(t->lwan, print_listening_msg);
467 if (listen_fd < 0)
468 lwan_status_critical("Could not create listen_fd")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 468, __FUNCTION__, "Could not create listen_fd")
;
469
470 struct epoll_event event = {
471 .events = EPOLLINEPOLLIN | EPOLLETEPOLLET | EPOLLERREPOLLERR,
472 .data.ptr = NULL((void*)0),
473 };
474 if (epoll_ctl(t->epoll_fd, EPOLL_CTL_ADD1, listen_fd, &event) < 0)
475 lwan_status_critical_perror("Could not add socket to epoll")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 475, __FUNCTION__, "Could not add socket to epoll")
;
476
477 return listen_fd;
478}
479
480static void *thread_io_loop(void *data)
481{
482 struct lwan_thread *t = data;
483 int epoll_fd = t->epoll_fd;
484 const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id4
= ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id5 = (1024); lwan_tmp_id4 > lwan_tmp_id5 ?
lwan_tmp_id5 : lwan_tmp_id4; })
;
485 struct lwan *lwan = t->lwan;
486 struct epoll_event *events;
487 struct coro_switcher switcher;
488 struct timeout_queue tq;
489
490 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 491, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
491 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 491, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
;
492 lwan_set_thread_name("worker");
493
494 events = calloc((size_t)max_events, sizeof(*events));
495 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
496 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"
, 496, __FUNCTION__, "Could not allocate memory for events")
;
497
498 update_date_cache(t);
499
500 timeout_queue_init(&tq, lwan);
501
502 pthread_barrier_wait(&lwan->thread.barrier);
503
504 for (;;) {
505 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
506 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
507
508 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
509 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
510 break;
511 continue;
512 }
513
514 for (struct epoll_event *event = events; n_fds--; event++) {
515 struct lwan_connection *conn;
516
517 if (!event->data.ptr) {
518 if (UNLIKELY(!try_accept_connections(t))__builtin_expect(((!try_accept_connections(t))), (0))) {
519 close(epoll_fd);
520 epoll_fd = -1;
521 break;
522 }
523 timeouts_add(t->wheel, &tq.timeout, 1000);
524 continue;
525 }
526
527 conn = event->data.ptr;
528
529 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))
) {
530 timeout_queue_expire(&tq, conn);
531 continue;
532 }
533
534 if (!conn->coro) {
535 spawn_coro(conn, &switcher, &tq);
536 continue;
537 }
538
539 resume_coro(&tq, conn, epoll_fd);
540 timeout_queue_move_to_last(&tq, conn);
541 }
542 }
543
544 pthread_barrier_wait(&lwan->thread.barrier);
545
546 timeout_queue_expire_all(&tq);
547 free(events);
548
549 return NULL((void*)0);
550}
551
552static void create_thread(struct lwan *l, struct lwan_thread *thread)
553{
554 int ignore;
555 pthread_attr_t attr;
556
557 memset(thread, 0, sizeof(*thread));
558 thread->lwan = l;
559
560 thread->wheel = timeouts_open(&ignore);
561 if (!thread->wheel)
562 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 562, __FUNCTION__, "Could not create timer wheel")
;
563
564 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
565 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 565, __FUNCTION__, "epoll_create")
;
566
567 if (pthread_attr_init(&attr))
568 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 568, __FUNCTION__, "pthread_attr_init")
;
569
570 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
571 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 571, __FUNCTION__, "pthread_attr_setscope")
;
572
573 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
574 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 574, __FUNCTION__, "pthread_attr_setdetachstate")
;
575
576 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
577 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 577, __FUNCTION__, "pthread_create")
;
578
579 if (pthread_attr_destroy(&attr))
580 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 580, __FUNCTION__, "pthread_attr_destroy")
;
581}
582
583#if defined(__linux__1) && defined(__x86_64__1)
584static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
585{
586 char path[PATH_MAX4096];
587
588 for (uint32_t i = 0; i < l->available_cpus; i++)
589 siblings[i] = 0xbebacafe;
590
591 for (unsigned int i = 0; i < l->available_cpus; i++) {
592 FILE *sib;
593 uint32_t id, sibling;
594 char separator;
595
596 snprintf(path, sizeof(path),
597 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
598 i);
599
600 sib = fopen(path, "re");
601 if (!sib) {
602 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"
, 603, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
603 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 603, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
;
604 return false0;
605 }
606
607 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
608 case 2: /* No SMT */
609 siblings[i] = id;
610 break;
611 case 3: /* SMT */
612 if (!(separator == ',' || separator == '-')) {
613 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"
, 613, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
)
;
614 __builtin_unreachable();
615 }
616
617 siblings[i] = sibling;
618 break;
619 default:
620 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 620, __FUNCTION__, "%s has invalid format", path)
;
621 __builtin_unreachable();
622 }
623
624 fclose(sib);
625 }
626
627 /* Perform a sanity check here, as some systems seem to filter out the
628 * result of sysconf() to obtain the number of configured and online
629 * CPUs but don't bother changing what's available through sysfs as far
630 * as the CPU topology information goes. It's better to fall back to a
631 * possibly non-optimal setup than just crash during startup while
632 * trying to perform an out-of-bounds array access. */
633 for (unsigned int i = 0; i < l->available_cpus; i++) {
634 if (siblings[i] == 0xbebacafe) {
635 lwan_status_warning("Could not determine sibling for CPU %d", i)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 635, __FUNCTION__, "Could not determine sibling for CPU %d"
, i)
;
636 return false0;
637 }
638
639 if (siblings[i] >= l->available_cpus) {
640 lwan_status_warning("CPU information topology says CPU %d exists, "lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 643, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
641 "but max available CPUs is %d (online CPUs: %d). "lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 643, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
642 "Is Lwan running in a (broken) container?",lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 643, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
643 siblings[i], l->available_cpus, l->online_cpus)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 643, __FUNCTION__, "CPU information topology says CPU %d exists, "
"but max available CPUs is %d (online CPUs: %d). " "Is Lwan running in a (broken) container?"
, siblings[i], l->available_cpus, l->online_cpus)
;
644 return false0;
645 }
646 }
647
648 return true1;
649}
650
651static void
652siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
653{
654 int *seen = alloca(l->available_cpus * sizeof(int))__builtin_alloca (l->available_cpus * sizeof(int));
655 unsigned int n_schedtbl = 0;
656
657 for (uint32_t i = 0; i < l->available_cpus; i++)
658 seen[i] = -1;
659
660 for (uint32_t i = 0; i < l->available_cpus; i++) {
661 if (seen[siblings[i]] < 0) {
662 seen[siblings[i]] = (int)i;
663 } else {
664 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
665 schedtbl[n_schedtbl++] = i;
666 }
667 }
668
669 if (n_schedtbl != l->available_cpus)
670 memcpy(schedtbl, seen, l->available_cpus * sizeof(int));
671}
672
673static bool_Bool
674topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
675{
676 uint32_t *siblings = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
677
678 if (read_cpu_topology(l, siblings)) {
10
Assuming the condition is true
11
Taking true branch
679 uint32_t *affinity = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
680
681 siblings_to_schedtbl(l, siblings, affinity);
682
683 for (uint32_t i = 0; i < n_threads; i++)
12
Assuming 'i' is >= 'n_threads'
13
Loop condition is false. Execution continues on line 685
684 schedtbl[i] = affinity[i % l->available_cpus];
685 return true1;
14
Returning without writing to '*schedtbl'
686 }
687
688 for (uint32_t i = 0; i < n_threads; i++)
689 schedtbl[i] = (i / 2) % l->thread.count;
690 return false0;
691}
692
693static void
694adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t mask)
695{
696 for (uint32_t i = 0; i < l->thread.count; i++) {
18
Assuming 'i' is < field 'count'
19
Loop condition is true. Entering loop body
697 cpu_set_t set;
698
699 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0)
;
20
Loop condition is false. Exiting loop
700 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; }))
;
21
Assigned value is garbage or undefined
701
702 if (pthread_setaffinity_np(l->thread.threads[i].self, sizeof(set),
703 &set))
704 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"
, 704, __FUNCTION__, "Could not set affinity for thread %d", i
)
;
705 }
706}
707#elif defined(__x86_64__1)
708static bool_Bool
709topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
710{
711 for (uint32_t i = 0; i < n_threads; i++)
712 schedtbl[i] = (i / 2) % l->thread.count;
713 return false0;
714}
715
716static void
717adjust_threads_affinity(struct lwan *l, uint32_t *schedtbl, uint32_t n)
718{
719}
720#endif
721
722void lwan_thread_init(struct lwan *l)
723{
724 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0),
1
Assuming the condition is false
2
Taking false branch
725 (unsigned)l->thread.count + 1))
726 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 726, __FUNCTION__, "Could not create barrier")
;
727
728 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 728, __FUNCTION__, "Initializing threads")
;
729
730 l->thread.threads =
731 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
732 if (!l->thread.threads)
3
Assuming field 'threads' is non-null
4
Taking false branch
733 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"
, 733, __FUNCTION__, "Could not allocate memory for threads")
;
734
735 for (unsigned int i = 0; i
4.1
'i' is < field 'count'
< l->thread.count
; i++) {
5
Loop condition is true. Entering loop body
7
Assuming 'i' is >= field 'count'
8
Loop condition is false. Execution continues on line 744
736 struct lwan_thread *thread = &l->thread.threads[i];
737
738 create_thread(l, thread);
739
740 if ((thread->listen_fd = create_listen_socket(thread, i == 0)) < 0)
6
Taking false branch
741 lwan_status_critical_perror("Could not create listening socket")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 741, __FUNCTION__, "Could not create listening socket")
;
742 }
743
744 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
745#ifdef __x86_64__1
746 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; })]
747 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })]
;
748
749 lwan_status_debug("%d CPUs of %d are online. "lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 751, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
750 "Reading topology to pre-schedule clients",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 751, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
751 l->online_cpus, l->available_cpus)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 751, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
;
752
753 /*
754 * Pre-schedule each file descriptor, to reduce some operations in the
755 * fast path.
756 *
757 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
758 * them can fill up a cache line. Assume siblings share cache lines and
759 * use the CPU topology to group two connections per cache line in such
760 * a way that false sharing is avoided.
761 */
762 uint32_t n_threads = (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
763 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
764
765 bool_Bool adj_affinity = topology_to_schedtbl(l, schedtbl, n_threads);
9
Calling 'topology_to_schedtbl'
15
Returning from 'topology_to_schedtbl'
766
767 n_threads--; /* Transform count into mask for AND below */
768
769 if (adj_affinity
15.1
'adj_affinity' is true
)
16
Taking true branch
770 adjust_threads_affinity(l, schedtbl, n_threads);
17
Calling 'adjust_threads_affinity'
771
772 for (unsigned int i = 0; i < total_conns; i++)
773 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
774#else
775 for (unsigned int i = 0; i < total_conns; i++)
776 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
777#endif
778
779 pthread_barrier_wait(&l->thread.barrier);
780
781 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"
, 781, __FUNCTION__, "Worker threads created and ready to serve"
)
;
782}
783
784void lwan_thread_shutdown(struct lwan *l)
785{
786 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 786, __FUNCTION__, "Shutting down threads")
;
787
788 for (unsigned int i = 0; i < l->thread.count; i++) {
789 struct lwan_thread *t = &l->thread.threads[i];
790 int epoll_fd = t->epoll_fd;
791 int listen_fd = t->listen_fd;
792
793 t->listen_fd = -1;
794 t->epoll_fd = -1;
795 close(epoll_fd);
796 close(listen_fd);
797 }
798
799 pthread_barrier_wait(&l->thread.barrier);
800 pthread_barrier_destroy(&l->thread.barrier);
801
802 for (unsigned int i = 0; i < l->thread.count; i++) {
803 struct lwan_thread *t = &l->thread.threads[i];
804
805 pthread_join(l->thread.threads[i].self, NULL((void*)0));
806 timeouts_close(t->wheel);
807 }
808
809 free(l->thread.threads);
810}