Bug Summary

File:lwan-thread.c
Warning:line 866, column 31
Array subscript is 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/2021-05-30-170345-1500789-1 -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_SO_ATTACH_REUSEPORT_CBPF)
35#include <linux1/filter.h>
36#endif
37
38#include "list.h"
39#include "murmur3.h"
40#include "lwan-private.h"
41#include "lwan-tq.h"
42
43static void lwan_strbuf_free_defer(void *data)
44{
45 lwan_strbuf_free((struct lwan_strbuf *)data);
46}
47
48static void graceful_close(struct lwan *l,
49 struct lwan_connection *conn,
50 char buffer[static DEFAULT_BUFFER_SIZE4096])
51{
52 int fd = lwan_connection_get_fd(l, conn);
53
54 while (TIOCOUTQ0x5411) {
55 /* This ioctl isn't probably doing what it says on the tin; the details
56 * are subtle, but it seems to do the trick to allow gracefully closing
57 * the connection in some cases with minimal system calls. */
58 int bytes_waiting;
59 int r = ioctl(fd, TIOCOUTQ0x5411, &bytes_waiting);
60
61 if (!r && !bytes_waiting) /* See note about close(2) below. */
62 return;
63 if (r < 0 && errno(*__errno_location ()) == EINTR4)
64 continue;
65
66 break;
67 }
68
69 if (UNLIKELY(shutdown(fd, SHUT_WR) < 0)__builtin_expect(((shutdown(fd, SHUT_WR) < 0)), (0))) {
70 if (UNLIKELY(errno == ENOTCONN)__builtin_expect((((*__errno_location ()) == 107)), (0)))
71 return;
72 }
73
74 for (int tries = 0; tries < 20; tries++) {
75 ssize_t r = recv(fd, buffer, DEFAULT_BUFFER_SIZE4096, 0);
76
77 if (!r)
78 break;
79
80 if (r < 0) {
81 switch (errno(*__errno_location ())) {
82 case EAGAIN11:
83 break;
84 case EINTR4:
85 continue;
86 default:
87 return;
88 }
89 }
90
91 coro_yield(conn->coro, CONN_CORO_WANT_READ);
92 }
93
94 /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
95}
96
97static __thread __uint128_t lehmer64_state;
98
99static void lwan_random_seed_prng_for_thread(const struct lwan_thread *t)
100{
101 if (lwan_getentropy(&lehmer64_state, sizeof(lehmer64_state), 0) < 0) {
102 lwan_status_warning("Couldn't get proper entropy for PRNG, using fallback seed")lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 102, __FUNCTION__, "Couldn't get proper entropy for PRNG, using fallback seed"
)
;
103 lehmer64_state |= murmur3_fmix64((uint64_t)(uintptr_t)t);
104 lehmer64_state <<= 64;
105 lehmer64_state |= murmur3_fmix64((uint64_t)t->epoll_fd);
106 }
107}
108
109uint64_t lwan_random_uint64()
110{
111 /* https://lemire.me/blog/2019/03/19/the-fastest-conventional-random-number-generator-that-can-pass-big-crush/ */
112 lehmer64_state *= 0xda942042e4dd58b5ull;
113 return (uint64_t)(lehmer64_state >> 64);
114}
115
116__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
117 void *data)
118{
119 /* NOTE: This function should not return; coro_yield should be used
120 * instead. This ensures the storage for `strbuf` is alive when the
121 * coroutine ends and lwan_strbuf_free() is called. */
122 struct lwan_connection *conn = data;
123 struct lwan *lwan = conn->thread->lwan;
124 int fd = lwan_connection_get_fd(lwan, conn);
125 enum lwan_request_flags flags = lwan->config.request_flags;
126 struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
127 char request_buffer[DEFAULT_BUFFER_SIZE4096];
128 struct lwan_value buffer = {.value = request_buffer, .len = 0};
129 char *next_request = NULL((void*)0);
130 char *header_start[N_HEADER_START64];
131 struct lwan_proxy proxy;
132 const int error_when_n_packets = lwan_calculate_n_packets(DEFAULT_BUFFER_SIZE4096);
133
134 coro_defer(coro, lwan_strbuf_free_defer, &strbuf);
135
136 const size_t init_gen = 1; /* 1 call to coro_defer() */
137 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"
, 137, __extension__ __PRETTY_FUNCTION__); }))
;
138
139 while (true1) {
140 struct lwan_request_parser_helper helper = {
141 .buffer = &buffer,
142 .next_request = next_request,
143 .error_when_n_packets = error_when_n_packets,
144 .header_start = header_start,
145 };
146 struct lwan_request request = {.conn = conn,
147 .global_response_headers = &lwan->headers,
148 .fd = fd,
149 .request_id = lwan_random_uint64(),
150 .response = {.buffer = &strbuf},
151 .flags = flags,
152 .proxy = &proxy,
153 .helper = &helper};
154
155 lwan_process_request(lwan, &request);
156
157 /* Run the deferred instructions now (except those used to initialize
158 * the coroutine), so that if the connection is gracefully closed,
159 * the storage for ``helper'' is still there. */
160 coro_deferred_run(coro, init_gen);
161
162 if (UNLIKELY(!(conn->flags & CONN_IS_KEEP_ALIVE))__builtin_expect(((!(conn->flags & CONN_IS_KEEP_ALIVE)
)), (0))
) {
163 graceful_close(lwan, conn, request_buffer);
164 break;
165 }
166
167 if (next_request && *next_request) {
168 conn->flags |= CONN_CORK;
169
170 if (!(conn->flags & CONN_EVENTS_WRITE))
171 coro_yield(coro, CONN_CORO_WANT_WRITE);
172 } else {
173 conn->flags &= ~CONN_CORK;
174 coro_yield(coro, CONN_CORO_WANT_READ);
175 }
176
177 /* Ensure string buffer is reset between requests, and that the backing
178 * store isn't over 2KB. */
179 lwan_strbuf_reset_trim(&strbuf, 2048);
180
181 /* Only allow flags from config. */
182 flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
183 next_request = helper.next_request;
184 }
185
186 coro_yield(coro, CONN_CORO_ABORT);
187 __builtin_unreachable();
188}
189
190static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
191conn_flags_to_epoll_events(enum lwan_connection_flags flags)
192{
193 static const uint32_t map[CONN_EVENTS_MASK + 1] = {
194 [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
195 [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
196 [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
197 [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
198 };
199
200 return map[flags & CONN_EVENTS_MASK];
201}
202
203static void update_epoll_flags(int fd,
204 struct lwan_connection *conn,
205 int epoll_fd,
206 enum lwan_connection_coro_yield yield_result)
207{
208 static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
209 [CONN_CORO_YIELD] = 0,
210
211 [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
212 [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
213 [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,
214
215 /* While the coro is suspended, we're not interested in either EPOLLIN
216 * or EPOLLOUT events. We still want to track this fd in epoll, though,
217 * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
218 * are set. */
219 [CONN_CORO_SUSPEND] = CONN_SUSPENDED,
220
221 /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
222 * would have to be stored and restored -- however, resuming as if the
223 * client coroutine is interested in a write event always guarantees that
224 * they'll be resumed as they're TCP sockets. There's a good chance that
225 * trying to read from a socket after resuming a coroutine will succeed,
226 * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
227 * yield with CONN_CORO_WANT_READ anyway. */
228 [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
229 };
230 static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
231 [CONN_CORO_YIELD] = ~0,
232
233 [CONN_CORO_WANT_READ_WRITE] = ~0,
234 [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
235 [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,
236
237 [CONN_CORO_SUSPEND] = ~CONN_EVENTS_READ_WRITE,
238 [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
239 };
240 enum lwan_connection_flags prev_flags = conn->flags;
241
242 conn->flags |= or_mask[yield_result];
243 conn->flags &= and_mask[yield_result];
244
245 if (conn->flags == prev_flags)
246 return;
247
248 struct epoll_event event = {
249 .events = conn_flags_to_epoll_events(conn->flags),
250 .data.ptr = conn,
251 };
252
253 if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
0)), (0))
)
254 lwan_status_perror("epoll_ctl")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 254, __FUNCTION__, "epoll_ctl")
;
255}
256
257static void clear_async_await_flag(void *data)
258{
259 struct lwan_connection *async_fd_conn = data;
260
261 async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
262}
263
264static enum lwan_connection_coro_yield
265resume_async(struct timeout_queue *tq,
266 enum lwan_connection_coro_yield yield_result,
267 int64_t from_coro,
268 struct lwan_connection *conn,
269 int epoll_fd)
270{
271 static const enum lwan_connection_flags to_connection_flags[] = {
272 [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
273 [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
274 [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
275 };
276 int await_fd = (int)((uint64_t)from_coro >> 32);
277 enum lwan_connection_flags flags;
278 int op;
279
280 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"
, 280, __extension__ __PRETTY_FUNCTION__); }))
;
281 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"
, 282, __extension__ __PRETTY_FUNCTION__); }))
282 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"
, 282, __extension__ __PRETTY_FUNCTION__); }))
;
283
284 flags = to_connection_flags[yield_result];
285
286 struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
287 if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))
) {
288 if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1))
)
289 return CONN_CORO_SUSPEND;
290
291 op = EPOLL_CTL_MOD3;
292 } else {
293 op = EPOLL_CTL_ADD1;
294 flags |= CONN_ASYNC_AWAIT;
295 coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
296 }
297
298 struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
299 .data.ptr = conn};
300 if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))
) {
301 await_fd_conn->flags &= ~CONN_EVENTS_MASK;
302 await_fd_conn->flags |= flags;
303 return CONN_CORO_SUSPEND;
304 }
305
306 return CONN_CORO_ABORT;
307}
308
309static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
310 struct lwan_connection *conn,
311 int epoll_fd)
312{
313 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"
, 313, __extension__ __PRETTY_FUNCTION__); }))
;
314
315 int64_t from_coro = coro_resume(conn->coro);
316 enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;
317
318 if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
319 yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);
320
321 if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
322 return timeout_queue_expire(tq, conn);
323
324 return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
325 epoll_fd, yield_result);
326}
327
328static void update_date_cache(struct lwan_thread *thread)
329{
330 time_t now = time(NULL((void*)0));
331
332 lwan_format_rfc_time(now, thread->date.date);
333 lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
334 thread->date.expires);
335}
336
337static bool_Bool send_buffer_without_coro(int fd, const char *buf, size_t buf_len)
338{
339 size_t total_sent = 0;
340
341 for (int try = 0; try < 10; try++) {
342 size_t to_send = buf_len - total_sent;
343 if (!to_send)
344 return true1;
345
346 ssize_t sent = write(fd, buf + total_sent, to_send);
347 if (sent <= 0) {
348 if (errno(*__errno_location ()) == EINTR4)
349 continue;
350 break;
351 }
352
353 total_sent += (size_t)sent;
354 }
355
356 return false0;
357}
358
359static bool_Bool send_string_without_coro(int fd, const char *str)
360{
361 return send_buffer_without_coro(fd, str, strlen(str));
362}
363
364static ALWAYS_INLINEinline __attribute__((always_inline)) bool_Bool spawn_coro(struct lwan_connection *conn,
365 struct coro_switcher *switcher,
366 struct timeout_queue *tq)
367{
368 struct lwan_thread *t = conn->thread;
369
370 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"
, 370, __extension__ __PRETTY_FUNCTION__); }))
;
371 assert(!(conn->flags & CONN_ASYNC_AWAIT))((void) sizeof ((!(conn->flags & CONN_ASYNC_AWAIT)) ? 1
: 0), __extension__ ({ if (!(conn->flags & CONN_ASYNC_AWAIT
)) ; else __assert_fail ("!(conn->flags & CONN_ASYNC_AWAIT)"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 371, __extension__ __PRETTY_FUNCTION__); }))
;
372 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"
, 372, __extension__ __PRETTY_FUNCTION__); }))
;
373 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"
, 373, __extension__ __PRETTY_FUNCTION__); }))
;
374 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"
, 375, __extension__ __PRETTY_FUNCTION__); }))
375 (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"
, 375, __extension__ __PRETTY_FUNCTION__); }))
;
376
377 *conn = (struct lwan_connection){
378 .coro = coro_new(switcher, process_request_coro, conn),
379 .flags = CONN_EVENTS_READ,
380 .time_to_expire = tq->current_time + tq->move_to_last_bump,
381 .thread = t,
382 };
383 if (LIKELY(conn->coro)__builtin_expect((!!(conn->coro)), (1))) {
384 timeout_queue_insert(tq, conn);
385 return true1;
386 }
387
388 conn->flags = 0;
389
390 int fd = lwan_connection_get_fd(tq->lwan, conn);
391
392 lwan_status_error("Couldn't spawn coroutine for file descriptor %d", fd)lwan_status_error_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 392, __FUNCTION__, "Couldn't spawn coroutine for file descriptor %d"
, fd)
;
393
394 if (!send_string_without_coro(fd, "HTTP/1.0 503 Unavailable"))
395 goto out;
396 if (!send_string_without_coro(fd, "\r\nConnection: close"))
397 goto out;
398 if (!send_string_without_coro(fd, "\r\nContent-Type: text/html"))
399 goto out;
400 if (send_buffer_without_coro(fd, lwan_strbuf_get_buffer(&tq->lwan->headers),
401 lwan_strbuf_get_length(&tq->lwan->headers))) {
402 struct lwan_strbuf buffer;
403
404 lwan_strbuf_init(&buffer);
405 lwan_fill_default_response(&buffer, HTTP_UNAVAILABLE);
406
407 send_buffer_without_coro(fd, lwan_strbuf_get_buffer(&buffer),
408 lwan_strbuf_get_length(&buffer));
409
410 lwan_strbuf_free(&buffer);
411 }
412
413out:
414 shutdown(fd, SHUT_RDWRSHUT_RDWR);
415 close(fd);
416 return false0;
417}
418
419static bool_Bool process_pending_timers(struct timeout_queue *tq,
420 struct lwan_thread *t,
421 int epoll_fd)
422{
423 struct timeout *timeout;
424 bool_Bool should_expire_timers = false0;
425
426 while ((timeout = timeouts_get(t->wheel))) {
427 struct lwan_request *request;
428
429 if (timeout == &tq->timeout) {
430 should_expire_timers = true1;
431 continue;
432 }
433
434 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))
;
435
436 update_epoll_flags(request->fd, request->conn, epoll_fd,
437 CONN_CORO_RESUME);
438 }
439
440 if (should_expire_timers) {
441 timeout_queue_expire_waiting(tq);
442
443 /* tq timeout expires every 1000ms if there are connections, so
444 * update the date cache at this point as well. */
445 update_date_cache(t);
446
447 if (!timeout_queue_empty(tq)) {
448 timeouts_add(t->wheel, &tq->timeout, 1000);
449 return true1;
450 }
451
452 timeouts_del(t->wheel, &tq->timeout);
453 }
454
455 return false0;
456}
457
458static int
459turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
460{
461 const int infinite_timeout = -1;
462 timeout_t wheel_timeout;
463 struct timespec now;
464
465 if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0))
)
466 lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 466, __FUNCTION__, "Could not get monotonic time")
;
467
468 timeouts_update(t->wheel,
469 (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));
470
471 /* Check if there's an expired timer. */
472 wheel_timeout = timeouts_timeout(t->wheel);
473 if (wheel_timeout > 0) {
474 return (int)wheel_timeout; /* No, but will soon. Wake us up in
475 wheel_timeout ms. */
476 }
477
478 if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
479 return infinite_timeout; /* None found. */
480
481 if (!process_pending_timers(tq, t, epoll_fd))
482 return infinite_timeout; /* No more timers to process. */
483
484 /* After processing pending timers, determine when to wake up. */
485 return (int)timeouts_timeout(t->wheel);
486}
487
488static bool_Bool accept_waiting_clients(const struct lwan_thread *t)
489{
490 const struct lwan_connection *conns = t->lwan->conns;
491
492 while (true1) {
493 int fd =
494 accept4(t->listen_fd, NULL((void*)0), NULL((void*)0), SOCK_NONBLOCKSOCK_NONBLOCK | SOCK_CLOEXECSOCK_CLOEXEC);
495
496 if (LIKELY(fd >= 0)__builtin_expect((!!(fd >= 0)), (1))) {
497 const struct lwan_connection *conn = &conns[fd];
498 struct epoll_event ev = {
499 .data.ptr = (void *)conn,
500 .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
501 };
502 int r = epoll_ctl(conn->thread->epoll_fd, EPOLL_CTL_ADD1, fd, &ev);
503
504 if (UNLIKELY(r < 0)__builtin_expect(((r < 0)), (0))) {
505 /* FIXME: send a "busy" response here? No coroutine has been
506 * created at this point to use the usual stuff, though. */
507 lwan_status_perror("Could not add file descriptor %d to epoll "lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 509, __FUNCTION__, "Could not add file descriptor %d to epoll "
"set %d. Dropping connection", fd, conn->thread->epoll_fd
)
508 "set %d. Dropping connection",lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 509, __FUNCTION__, "Could not add file descriptor %d to epoll "
"set %d. Dropping connection", fd, conn->thread->epoll_fd
)
509 fd, conn->thread->epoll_fd)lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 509, __FUNCTION__, "Could not add file descriptor %d to epoll "
"set %d. Dropping connection", fd, conn->thread->epoll_fd
)
;
510 shutdown(fd, SHUT_RDWRSHUT_RDWR);
511 close(fd);
512 }
513
514 continue;
515 }
516
517 switch (errno(*__errno_location ())) {
518 default:
519 lwan_status_perror("Unexpected error while accepting connections")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 519, __FUNCTION__, "Unexpected error while accepting connections"
)
;
520 /* fallthrough */
521
522 case EAGAIN11:
523 return true1;
524
525 case EBADF9:
526 case ECONNABORTED103:
527 case EINVAL22:
528 lwan_status_info("Listening socket closed")lwan_status_info_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 528, __FUNCTION__, "Listening socket closed")
;
529 return false0;
530 }
531 }
532
533 __builtin_unreachable();
534}
535
536static int create_listen_socket(struct lwan_thread *t,
537 unsigned int num)
538{
539 int listen_fd;
540
541 listen_fd = lwan_create_listen_socket(t->lwan, num == 0);
542 if (listen_fd < 0)
543 lwan_status_critical("Could not create listen_fd")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 543, __FUNCTION__, "Could not create listen_fd")
;
544
545 /* Ignore errors here, as this is just a hint */
546#if defined(HAVE_SO_ATTACH_REUSEPORT_CBPF)
547 /* From socket(7): "These options may be set repeatedly at any time on
548 * any socket in the group to replace the current BPF program used by
549 * all sockets in the group." */
550 if (num == 0) {
551 /* From socket(7): "The BPF program must return an index between 0 and
552 * N-1 representing the socket which should receive the packet (where N
553 * is the number of sockets in the group)." */
554 const uint32_t cpu_ad_off = (uint32_t)SKF_AD_OFF(-0x1000) + SKF_AD_CPU36;
555 struct sock_filter filter[] = {
556 {BPF_LD0x00 | BPF_W0x00 | BPF_ABS0x20, 0, 0, cpu_ad_off}, /* A = curr_cpu_index */
557 {BPF_RET0x06 | BPF_A0x10, 0, 0, 0}, /* return A */
558 };
559 struct sock_fprog fprog = {.filter = filter, .len = N_ELEMENTS(filter)((!sizeof(char[1 - 2 * __builtin_types_compatible_p( __typeof__
(filter), __typeof__(&(filter)[0]))])) | sizeof(filter) /
sizeof(filter[0]))
};
560
561 (void)setsockopt(listen_fd, SOL_SOCKET1, SO_ATTACH_REUSEPORT_CBPF51,
562 &fprog, sizeof(fprog));
563 (void)setsockopt(listen_fd, SOL_SOCKET1, SO_LOCK_FILTER44,
564 (int[]){1}, sizeof(int));
565 }
566#elif defined(HAVE_SO_INCOMING_CPU) && defined(__x86_64__1)
567 (void)setsockopt(listen_fd, SOL_SOCKET1, SO_INCOMING_CPU49, &t->cpu,
568 sizeof(t->cpu));
569#endif
570
571 struct epoll_event event = {
572 .events = EPOLLINEPOLLIN | EPOLLETEPOLLET | EPOLLERREPOLLERR,
573 .data.ptr = NULL((void*)0),
574 };
575 if (epoll_ctl(t->epoll_fd, EPOLL_CTL_ADD1, listen_fd, &event) < 0)
576 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"
, 576, __FUNCTION__, "Could not add socket to epoll")
;
577
578 return listen_fd;
579}
580
581static void *thread_io_loop(void *data)
582{
583 struct lwan_thread *t = data;
584 int epoll_fd = t->epoll_fd;
585 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; })
;
586 struct lwan *lwan = t->lwan;
587 struct epoll_event *events;
588 struct coro_switcher switcher;
589 struct timeout_queue tq;
590
591 lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 592, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
592 t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 592, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
;
593 lwan_set_thread_name("worker");
594
595 events = calloc((size_t)max_events, sizeof(*events));
596 if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
597 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"
, 597, __FUNCTION__, "Could not allocate memory for events")
;
598
599 update_date_cache(t);
600
601 timeout_queue_init(&tq, lwan);
602
603 lwan_random_seed_prng_for_thread(t);
604
605 pthread_barrier_wait(&lwan->thread.barrier);
606
607 for (;;) {
608 int timeout = turn_timer_wheel(&tq, t, epoll_fd);
609 int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
610 bool_Bool accepted_connections = false0;
611
612 if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
613 if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
614 break;
615 continue;
616 }
617
618 for (struct epoll_event *event = events; n_fds--; event++) {
619 struct lwan_connection *conn;
620
621 if (!event->data.ptr) {
622 if (LIKELY(accept_waiting_clients(t))__builtin_expect((!!(accept_waiting_clients(t))), (1))) {
623 accepted_connections = true1;
624 continue;
625 }
626 close(epoll_fd);
627 epoll_fd = -1;
628 break;
629 }
630
631 conn = event->data.ptr;
632
633 if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))
) {
634 timeout_queue_expire(&tq, conn);
635 continue;
636 }
637
638 if (!conn->coro) {
639 if (UNLIKELY(!spawn_coro(conn, &switcher, &tq))__builtin_expect(((!spawn_coro(conn, &switcher, &tq))
), (0))
)
640 continue;
641 }
642
643 resume_coro(&tq, conn, epoll_fd);
644 timeout_queue_move_to_last(&tq, conn);
645 }
646
647 if (accepted_connections)
648 timeouts_add(t->wheel, &tq.timeout, 1000);
649 }
650
651 pthread_barrier_wait(&lwan->thread.barrier);
652
653 timeout_queue_expire_all(&tq);
654 free(events);
655
656 return NULL((void*)0);
657}
658
659static void create_thread(struct lwan *l, struct lwan_thread *thread)
660{
661 int ignore;
662 pthread_attr_t attr;
663
664 thread->lwan = l;
665
666 thread->wheel = timeouts_open(&ignore);
667 if (!thread->wheel)
668 lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 668, __FUNCTION__, "Could not create timer wheel")
;
669
670 if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
671 lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 671, __FUNCTION__, "epoll_create")
;
672
673 if (pthread_attr_init(&attr))
674 lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 674, __FUNCTION__, "pthread_attr_init")
;
675
676 if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
677 lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 677, __FUNCTION__, "pthread_attr_setscope")
;
678
679 if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
680 lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 680, __FUNCTION__, "pthread_attr_setdetachstate")
;
681
682 if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
683 lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 683, __FUNCTION__, "pthread_create")
;
684
685 if (pthread_attr_destroy(&attr))
686 lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 686, __FUNCTION__, "pthread_attr_destroy")
;
687}
688
689#if defined(__linux__1) && defined(__x86_64__1)
690static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
691{
692 char path[PATH_MAX4096];
693
694 for (uint32_t i = 0; i < l->available_cpus; i++)
695 siblings[i] = 0xbebacafe;
696
697 for (unsigned int i = 0; i < l->available_cpus; i++) {
698 FILE *sib;
699 uint32_t id, sibling;
700 char separator;
701
702 snprintf(path, sizeof(path),
703 "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
704 i);
705
706 sib = fopen(path, "re");
707 if (!sib) {
708 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"
, 709, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
709 path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 709, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
;
710 return false0;
711 }
712
713 switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
714 case 2: /* No SMT */
715 siblings[i] = id;
716 break;
717 case 3: /* SMT */
718 if (!(separator == ',' || separator == '-')) {
719 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"
, 719, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
)
;
720 __builtin_unreachable();
721 }
722
723 siblings[i] = sibling;
724 break;
725 default:
726 lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 726, __FUNCTION__, "%s has invalid format", path)
;
727 __builtin_unreachable();
728 }
729
730 fclose(sib);
731 }
732
733 /* Perform a sanity check here, as some systems seem to filter out the
734 * result of sysconf() to obtain the number of configured and online
735 * CPUs but don't bother changing what's available through sysfs as far
736 * as the CPU topology information goes. It's better to fall back to a
737 * possibly non-optimal setup than just crash during startup while
738 * trying to perform an out-of-bounds array access. */
739 for (unsigned int i = 0; i < l->available_cpus; i++) {
740 if (siblings[i] == 0xbebacafe) {
741 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"
, 741, __FUNCTION__, "Could not determine sibling for CPU %d"
, i)
;
742 return false0;
743 }
744
745 if (siblings[i] >= l->available_cpus) {
746 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"
, 749, __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)
747 "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"
, 749, __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)
748 "Is Lwan running in a (broken) container?",lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 749, __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)
749 siblings[i], l->available_cpus, l->online_cpus)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 749, __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)
;
750 return false0;
751 }
752 }
753
754 return true1;
755}
756
757static void
758siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
759{
760 int *seen = alloca(l->available_cpus * sizeof(int))__builtin_alloca (l->available_cpus * sizeof(int));
761 unsigned int n_schedtbl = 0;
762
763 for (uint32_t i = 0; i < l->available_cpus; i++)
764 seen[i] = -1;
765
766 for (uint32_t i = 0; i < l->available_cpus; i++) {
767 if (seen[siblings[i]] < 0) {
768 seen[siblings[i]] = (int)i;
769 } else {
770 schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
771 schedtbl[n_schedtbl++] = i;
772 }
773 }
774
775 if (n_schedtbl != l->available_cpus)
776 memcpy(schedtbl, seen, l->available_cpus * sizeof(int));
777}
778
779static bool_Bool
780topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
781{
782 uint32_t *siblings = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
783
784 if (read_cpu_topology(l, siblings)) {
6
Assuming the condition is false
7
Taking false branch
785 uint32_t *affinity = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));
786
787 siblings_to_schedtbl(l, siblings, affinity);
788
789 for (uint32_t i = 0; i < n_threads; i++)
790 schedtbl[i] = affinity[i % l->available_cpus];
791 return true1;
792 }
793
794 for (uint32_t i = 0; i < n_threads; i++)
8
Assuming 'i' is >= 'n_threads'
9
Loop condition is false. Execution continues on line 796
795 schedtbl[i] = (i / 2) % l->thread.count;
796 return false0;
10
Returning without writing to '*schedtbl'
797}
798
799static void
800adjust_thread_affinity(const struct lwan_thread *thread)
801{
802 cpu_set_t set;
803
804 CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
(0)
;
805 CPU_SET(thread->cpu, &set)(__extension__ ({ size_t __cpu = (thread->cpu); __cpu / 8 <
(sizeof (cpu_set_t)) ? (((__cpu_mask *) ((&set)->__bits
))[((__cpu) / (8 * sizeof (__cpu_mask)))] |= ((__cpu_mask) 1 <<
((__cpu) % (8 * sizeof (__cpu_mask))))) : 0; }))
;
806
807 if (pthread_setaffinity_np(thread->self, sizeof(set), &set))
808 lwan_status_warning("Could not set thread affinity")lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 808, __FUNCTION__, "Could not set thread affinity")
;
809}
810#elif defined(__x86_64__1)
811static bool_Bool
812topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
813{
814 for (uint32_t i = 0; i < n_threads; i++)
815 schedtbl[i] = (i / 2) % l->thread.count;
816 return false0;
817}
818
819static void
820adjust_thread_affinity(const struct lwan_thread *thread)
821{
822 (void)thread;
823}
824#endif
825
826void lwan_thread_init(struct lwan *l)
827{
828 const unsigned int total_conns = l->thread.max_fd * l->thread.count;
829
830 lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 830, __FUNCTION__, "Initializing threads")
;
831
832 l->thread.threads =
833 calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
834 if (!l->thread.threads)
1
Assuming field 'threads' is non-null
2
Taking false branch
835 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"
, 835, __FUNCTION__, "Could not allocate memory for threads")
;
836
837#ifdef __x86_64__1
838 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; })]
839 "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
{ int __error_if_negative: (sizeof(struct lwan_connection) ==
32) ? 2 : -1; })]
;
840#ifdef _SC_LEVEL1_DCACHE_LINESIZE_SC_LEVEL1_DCACHE_LINESIZE
841 assert(sysconf(_SC_LEVEL1_DCACHE_LINESIZE) == 64)((void) sizeof ((sysconf(_SC_LEVEL1_DCACHE_LINESIZE) == 64) ?
1 : 0), __extension__ ({ if (sysconf(_SC_LEVEL1_DCACHE_LINESIZE
) == 64) ; else __assert_fail ("sysconf(_SC_LEVEL1_DCACHE_LINESIZE) == 64"
, "/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 841, __extension__ __PRETTY_FUNCTION__); }))
;
3
Assuming the condition is true
4
Taking true branch
842#endif
843
844 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"
, 846, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
845 "Reading topology to pre-schedule clients",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 846, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
846 l->online_cpus, l->available_cpus)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 846, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
;
847
848 /*
849 * Pre-schedule each file descriptor, to reduce some operations in the
850 * fast path.
851 *
852 * Since struct lwan_connection is guaranteed to be 32-byte long, two of
853 * them can fill up a cache line. Assume siblings share cache lines and
854 * use the CPU topology to group two connections per cache line in such
855 * a way that false sharing is avoided.
856 */
857 uint32_t n_threads =
858 (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
859 uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));
860
861 bool_Bool adj_affinity = topology_to_schedtbl(l, schedtbl, n_threads);
5
Calling 'topology_to_schedtbl'
11
Returning from 'topology_to_schedtbl'
862
863 n_threads--; /* Transform count into mask for AND below */
864
865 for (unsigned int i = 0; i < total_conns; i++)
12
Assuming 'i' is < 'total_conns'
13
Loop condition is true. Entering loop body
866 l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
14
Array subscript is undefined
867#else
868 for (unsigned int i = 0; i < l->thread.count; i++)
869 l->thread.threads[i].cpu = i % l->online_cpus;
870 for (unsigned int i = 0; i < total_conns; i++)
871 l->conns[i].thread = &l->thread.threads[i % l->thread.count];
872
873 uint32_t *schedtbl = NULL((void*)0);
874 const bool_Bool adj_affinity = false0;
875#endif
876
877 for (unsigned int i = 0; i < l->thread.count; i++) {
878 struct lwan_thread *thread = NULL((void*)0);
879
880 if (schedtbl) {
881 /* This is not the most elegant thing, but this assures that the
882 * listening sockets are added to the SO_REUSEPORT group in a
883 * specific order, because that's what the CBPF program to direct
884 * the incoming connection to the right CPU will use. */
885 for (uint32_t thread_id = 0; thread_id < l->thread.count;
886 thread_id++) {
887 if (schedtbl[thread_id & n_threads] == i) {
888 thread = &l->thread.threads[thread_id];
889 break;
890 }
891 }
892 if (!thread) {
893 /* FIXME: can this happen when we have a offline CPU? */
894 lwan_status_critical(lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 895, __FUNCTION__, "Could not figure out which CPU thread %d should go to"
, i)
895 "Could not figure out which CPU thread %d should go to", i)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 895, __FUNCTION__, "Could not figure out which CPU thread %d should go to"
, i)
;
896 }
897 } else {
898 thread = &l->thread.threads[i % l->thread.count];
899 }
900
901 if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0), 2))
902 lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 902, __FUNCTION__, "Could not create barrier")
;
903
904 create_thread(l, thread);
905
906 if ((thread->listen_fd = create_listen_socket(thread, i)) < 0)
907 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"
, 907, __FUNCTION__, "Could not create listening socket")
;
908
909 if (adj_affinity) {
910 l->thread.threads[i].cpu = schedtbl[i & n_threads];
911 adjust_thread_affinity(thread);
912 }
913
914 pthread_barrier_wait(&l->thread.barrier);
915 }
916
917 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"
, 917, __FUNCTION__, "Worker threads created and ready to serve"
)
;
918}
919
920void lwan_thread_shutdown(struct lwan *l)
921{
922 lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 922, __FUNCTION__, "Shutting down threads")
;
923
924 for (unsigned int i = 0; i < l->thread.count; i++) {
925 struct lwan_thread *t = &l->thread.threads[i];
926 int epoll_fd = t->epoll_fd;
927 int listen_fd = t->listen_fd;
928
929 t->listen_fd = -1;
930 t->epoll_fd = -1;
931 close(epoll_fd);
932 close(listen_fd);
933 }
934
935 pthread_barrier_wait(&l->thread.barrier);
936 pthread_barrier_destroy(&l->thread.barrier);
937
938 for (unsigned int i = 0; i < l->thread.count; i++) {
939 struct lwan_thread *t = &l->thread.threads[i];
940
941 pthread_join(l->thread.threads[i].self, NULL((void*)0));
942 timeouts_close(t->wheel);
943 }
944
945 free(l->thread.threads);
946}