/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c

Bug Summary

File:	lwan-thread.c
Warning:	line 900, column 53 The left operand of '==' is a garbage value
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 -fhalf-no-semantic-interposition -mframe-pointer=all -fmath-errno -fno-rounding-math -mconstructor-aliases -fno-plt -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/clang/12.0.0 -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/12.0.0/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 -stack-protector 2 -fgnuc-version=4.2.1 -analyzer-output=html -faddrsig -o /home/buildbot/lwan-worker/clang-analyze/CLANG/2021-06-11-154846-2293703-1 -x c /home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c
1/*
* lwan - simple web server
* Copyright (c) 2012, 2013 Leandro A. F. Pereira <leandro@hardinfo.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
* USA.
*/

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>

34#if defined(HAVE_SO_ATTACH_REUSEPORT_CBPF)
35#include <linux1/filter.h>
36#endif

38#include "list.h"
39#include "murmur3.h"
40#include "lwan-private.h"
41#include "lwan-tq.h"

43static void lwan_strbuf_free_defer(void *data)
44{
  lwan_strbuf_free((struct lwan_strbuf *)data);
46}

48static void graceful_close(struct lwan *l,
                         struct lwan_connection *conn,
                         char buffer[static DEFAULT_BUFFER_SIZE4096])
51{
  int fd = lwan_connection_get_fd(l, conn);

  while (TIOCOUTQ0x5411) {
      /* This ioctl isn't probably doing what it says on the tin; the details
       * are subtle, but it seems to do the trick to allow gracefully closing
       * the connection in some cases with minimal system calls. */
      int bytes_waiting;
      int r = ioctl(fd, TIOCOUTQ0x5411, &bytes_waiting);

      if (!r && !bytes_waiting) /* See note about close(2) below. */
          return;
      if (r < 0 && errno(*__errno_location ()) == EINTR4)
          continue;

      break;
  }

  if (UNLIKELY(shutdown(fd, SHUT_WR) < 0)__builtin_expect(((shutdown(fd, SHUT_WR) < 0)), (0))) {
      if (UNLIKELY(errno == ENOTCONN)__builtin_expect((((*__errno_location ()) == 107)), (0)))
          return;
  }

  for (int tries = 0; tries < 20; tries++) {
      ssize_t r = recv(fd, buffer, DEFAULT_BUFFER_SIZE4096, 0);

      if (!r)
          break;

      if (r < 0) {
          switch (errno(*__errno_location ())) {
          case EAGAIN11:
              break;
          case EINTR4:
              continue;
          default:
              return;
          }
      }

      coro_yield(conn->coro, CONN_CORO_WANT_READ);
  }

  /* close(2) will be called when the coroutine yields with CONN_CORO_ABORT */
95}

97static __thread __uint128_t lehmer64_state;

99static void lwan_random_seed_prng_for_thread(const struct lwan_thread *t)
100{
  if (lwan_getentropy(&lehmer64_state, sizeof(lehmer64_state), 0) < 0) {
      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"
);
      lehmer64_state |= murmur3_fmix64((uint64_t)(uintptr_t)t);
      lehmer64_state <<= 64;
      lehmer64_state |= murmur3_fmix64((uint64_t)t->epoll_fd);
  }
107}

109uint64_t lwan_random_uint64()
110{
  /* https://lemire.me/blog/2019/03/19/the-fastest-conventional-random-number-generator-that-can-pass-big-crush/ */
  lehmer64_state *= 0xda942042e4dd58b5ull;
  return (uint64_t)(lehmer64_state >> 64);
114}

116__attribute__((noreturn)) static int process_request_coro(struct coro *coro,
                                                        void *data)
118{
  /* NOTE: This function should not return; coro_yield should be used
   * instead.  This ensures the storage for `strbuf` is alive when the
   * coroutine ends and lwan_strbuf_free() is called. */
  struct lwan_connection *conn = data;
  struct lwan *lwan = conn->thread->lwan;
  int fd = lwan_connection_get_fd(lwan, conn);
  enum lwan_request_flags flags = lwan->config.request_flags;
  struct lwan_strbuf strbuf = LWAN_STRBUF_STATIC_INIT(struct lwan_strbuf) { .buffer = "" };
  char request_buffer[DEFAULT_BUFFER_SIZE4096];
  struct lwan_value buffer = {.value = request_buffer, .len = 0};
  char *next_request = NULL((void*)0);
  char *header_start[N_HEADER_START64];
  struct lwan_proxy proxy;
  const int error_when_n_packets = lwan_calculate_n_packets(DEFAULT_BUFFER_SIZE4096);

  coro_defer(coro, lwan_strbuf_free_defer, &strbuf);

  const size_t init_gen = 1; /* 1 call to coro_defer() */
  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__); }));

  while (true1) {
      struct lwan_request_parser_helper helper = {
          .buffer = &buffer,
          .next_request = next_request,
          .error_when_n_packets = error_when_n_packets,
          .header_start = header_start,
      };
      struct lwan_request request = {.conn = conn,
                                     .global_response_headers = &lwan->headers,
                                     .fd = fd,
                                     .request_id = lwan_random_uint64(),
                                     .response = {.buffer = &strbuf},
                                     .flags = flags,
                                     .proxy = &proxy,
                                     .helper = &helper};

      lwan_process_request(lwan, &request);

      /* Run the deferred instructions now (except those used to initialize
       * the coroutine), so that if the connection is gracefully closed,
       * the storage for ``helper'' is still there. */
      coro_deferred_run(coro, init_gen);

      if (UNLIKELY(!(conn->flags & CONN_IS_KEEP_ALIVE))__builtin_expect(((!(conn->flags & CONN_IS_KEEP_ALIVE)
)), (0))) {
          graceful_close(lwan, conn, request_buffer);
          break;
      }

      if (next_request && *next_request) {
          conn->flags |= CONN_CORK;

          if (!(conn->flags & CONN_EVENTS_WRITE))
              coro_yield(coro, CONN_CORO_WANT_WRITE);
      } else {
          conn->flags &= ~CONN_CORK;
          coro_yield(coro, CONN_CORO_WANT_READ);
      }

      /* Ensure string buffer is reset between requests, and that the backing
       * store isn't over 2KB. */
      lwan_strbuf_reset_trim(&strbuf, 2048);

      /* Only allow flags from config. */
      flags = request.flags & (REQUEST_PROXIED | REQUEST_ALLOW_CORS);
      next_request = helper.next_request;
  }

  coro_yield(coro, CONN_CORO_ABORT);
  __builtin_unreachable();
188}

190static ALWAYS_INLINEinline __attribute__((always_inline)) uint32_t
191conn_flags_to_epoll_events(enum lwan_connection_flags flags)
192{
  static const uint32_t map[CONN_EVENTS_MASK + 1] = {
      [0 /* Suspended (timer or await) */] = EPOLLRDHUPEPOLLRDHUP,
      [CONN_EVENTS_WRITE] = EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
      [CONN_EVENTS_READ] = EPOLLINEPOLLIN | EPOLLRDHUPEPOLLRDHUP,
      [CONN_EVENTS_READ_WRITE] = EPOLLINEPOLLIN | EPOLLOUTEPOLLOUT | EPOLLRDHUPEPOLLRDHUP,
  };

  return map[flags & CONN_EVENTS_MASK];
201}

203static void update_epoll_flags(int fd,
                             struct lwan_connection *conn,
                             int epoll_fd,
                             enum lwan_connection_coro_yield yield_result)
207{
  static const enum lwan_connection_flags or_mask[CONN_CORO_MAX] = {
      [CONN_CORO_YIELD] = 0,

      [CONN_CORO_WANT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
      [CONN_CORO_WANT_READ] = CONN_EVENTS_READ,
      [CONN_CORO_WANT_WRITE] = CONN_EVENTS_WRITE,

      /* While the coro is suspended, we're not interested in either EPOLLIN
       * or EPOLLOUT events.  We still want to track this fd in epoll, though,
       * so unset both so that only EPOLLRDHUP (plus the implicitly-set ones)
       * are set. */
      [CONN_CORO_SUSPEND] = CONN_SUSPENDED,

      /* Ideally, when suspending a coroutine, the current flags&CONN_EVENTS_MASK
       * would have to be stored and restored -- however, resuming as if the
       * client coroutine is interested in a write event always guarantees that
       * they'll be resumed as they're TCP sockets.  There's a good chance that
       * trying to read from a socket after resuming a coroutine will succeed,
       * but if it doesn't because read() returns -EAGAIN, the I/O wrappers will
       * yield with CONN_CORO_WANT_READ anyway.  */
      [CONN_CORO_RESUME] = CONN_EVENTS_WRITE,
  };
  static const enum lwan_connection_flags and_mask[CONN_CORO_MAX] = {
      [CONN_CORO_YIELD] = ~0,

      [CONN_CORO_WANT_READ_WRITE] = ~0,
      [CONN_CORO_WANT_READ] = ~CONN_EVENTS_WRITE,
      [CONN_CORO_WANT_WRITE] = ~CONN_EVENTS_READ,

      [CONN_CORO_SUSPEND] = ~CONN_EVENTS_READ_WRITE,
      [CONN_CORO_RESUME] = ~CONN_SUSPENDED,
  };
  enum lwan_connection_flags prev_flags = conn->flags;

  conn->flags |= or_mask[yield_result];
  conn->flags &= and_mask[yield_result];

  if (conn->flags == prev_flags)
      return;

  struct epoll_event event = {
      .events = conn_flags_to_epoll_events(conn->flags),
      .data.ptr = conn,
  };

  if (UNLIKELY(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fd, &event) < 0)__builtin_expect(((epoll_ctl(epoll_fd, 3, fd, &event) <
 0)), (0)))
      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}

257static void clear_async_await_flag(void *data)
258{
  struct lwan_connection *async_fd_conn = data;

  async_fd_conn->flags &= ~CONN_ASYNC_AWAIT;
262}

264static enum lwan_connection_coro_yield
265resume_async(struct timeout_queue *tq,
           enum lwan_connection_coro_yield yield_result,
           int64_t from_coro,
           struct lwan_connection *conn,
           int epoll_fd)
270{
  static const enum lwan_connection_flags to_connection_flags[] = {
      [CONN_CORO_ASYNC_AWAIT_READ] = CONN_EVENTS_READ,
      [CONN_CORO_ASYNC_AWAIT_WRITE] = CONN_EVENTS_WRITE,
      [CONN_CORO_ASYNC_AWAIT_READ_WRITE] = CONN_EVENTS_READ_WRITE,
  };
  int await_fd = (int)((uint64_t)from_coro >> 32);
  enum lwan_connection_flags flags;
  int op;

  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__); }));
  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__); }))
         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__); }));

  flags = to_connection_flags[yield_result];

  struct lwan_connection *await_fd_conn = &tq->lwan->conns[await_fd];
  if (LIKELY(await_fd_conn->flags & CONN_ASYNC_AWAIT)__builtin_expect((!!(await_fd_conn->flags & CONN_ASYNC_AWAIT
)), (1))) {
      if (LIKELY((await_fd_conn->flags & CONN_EVENTS_MASK) == flags)__builtin_expect((!!((await_fd_conn->flags & CONN_EVENTS_MASK
) == flags)), (1)))
          return CONN_CORO_SUSPEND;

      op = EPOLL_CTL_MOD3;
  } else {
      op = EPOLL_CTL_ADD1;
      flags |= CONN_ASYNC_AWAIT;
      coro_defer(conn->coro, clear_async_await_flag, await_fd_conn);
  }

  struct epoll_event event = {.events = conn_flags_to_epoll_events(flags),
                              .data.ptr = conn};
  if (LIKELY(!epoll_ctl(epoll_fd, op, await_fd, &event))__builtin_expect((!!(!epoll_ctl(epoll_fd, op, await_fd, &
event))), (1))) {
      await_fd_conn->flags &= ~CONN_EVENTS_MASK;
      await_fd_conn->flags |= flags;
      return CONN_CORO_SUSPEND;
  }

  return CONN_CORO_ABORT;
307}

309static ALWAYS_INLINEinline __attribute__((always_inline)) void resume_coro(struct timeout_queue *tq,
                                    struct lwan_connection *conn,
                                    int epoll_fd)
312{
  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__); }));

  int64_t from_coro = coro_resume(conn->coro);
  enum lwan_connection_coro_yield yield_result = from_coro & 0xffffffff;

  if (UNLIKELY(yield_result >= CONN_CORO_ASYNC)__builtin_expect(((yield_result >= CONN_CORO_ASYNC)), (0)))
      yield_result = resume_async(tq, yield_result, from_coro, conn, epoll_fd);

  if (UNLIKELY(yield_result == CONN_CORO_ABORT)__builtin_expect(((yield_result == CONN_CORO_ABORT)), (0)))
      return timeout_queue_expire(tq, conn);

  return update_epoll_flags(lwan_connection_get_fd(tq->lwan, conn), conn,
                            epoll_fd, yield_result);
326}

328static void update_date_cache(struct lwan_thread *thread)
329{
  time_t now = time(NULL((void*)0));

  lwan_format_rfc_time(now, thread->date.date);
  lwan_format_rfc_time(now + (time_t)thread->lwan->config.expires,
                       thread->date.expires);
335}

337static bool_Bool send_buffer_without_coro(int fd, const char *buf, size_t buf_len, int flags)
338{
  size_t total_sent = 0;

  for (int try = 0; try < 10; try++) {
      size_t to_send = buf_len - total_sent;
      if (!to_send)
          return true1;

      ssize_t sent = send(fd, buf + total_sent, to_send, flags);
      if (sent <= 0) {
          if (errno(*__errno_location ()) == EINTR4)
              continue;
          break;
      }

      total_sent += (size_t)sent;
  }

  return false0;
357}

359static bool_Bool send_string_without_coro(int fd, const char *str, int flags)
360{
  return send_buffer_without_coro(fd, str, strlen(str), flags);
362}

364static void send_response_without_coro(const struct lwan *l,
                                     int fd,
                                     enum lwan_http_status status)
367{
  if (!send_string_without_coro(fd, "HTTP/1.0 ", MSG_MOREMSG_MORE))
      return;

  if (!send_string_without_coro(
          fd, lwan_http_status_as_string_with_code(status), MSG_MOREMSG_MORE))
      return;

  if (!send_string_without_coro(fd, "\r\nConnection: close", MSG_MOREMSG_MORE))
      return;

  if (!send_string_without_coro(fd, "\r\nContent-Type: text/html", MSG_MOREMSG_MORE))
      return;

  if (send_buffer_without_coro(fd, lwan_strbuf_get_buffer(&l->headers),
                               lwan_strbuf_get_length(&l->headers),
                               MSG_MOREMSG_MORE)) {
      struct lwan_strbuf buffer;

      lwan_strbuf_init(&buffer);
      lwan_fill_default_response(&buffer, status);

      send_buffer_without_coro(fd, lwan_strbuf_get_buffer(&buffer),
                               lwan_strbuf_get_length(&buffer), 0);

      lwan_strbuf_free(&buffer);
  }
394}

396static ALWAYS_INLINEinline __attribute__((always_inline)) bool_Bool spawn_coro(struct lwan_connection *conn,
                                   struct coro_switcher *switcher,
                                   struct timeout_queue *tq)
399{
  struct lwan_thread *t = conn->thread;

  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"
, 402, __extension__ __PRETTY_FUNCTION__); }));
  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"
, 403, __extension__ __PRETTY_FUNCTION__); }));
  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"
, 404, __extension__ __PRETTY_FUNCTION__); }));
  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"
, 405, __extension__ __PRETTY_FUNCTION__); }));
  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"
, 407, __extension__ __PRETTY_FUNCTION__); }))
         (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"
, 407, __extension__ __PRETTY_FUNCTION__); }));

  *conn = (struct lwan_connection){
      .coro = coro_new(switcher, process_request_coro, conn),
      .flags = CONN_EVENTS_READ,
      .time_to_expire = tq->current_time + tq->move_to_last_bump,
      .thread = t,
  };
  if (LIKELY(conn->coro)__builtin_expect((!!(conn->coro)), (1))) {
      timeout_queue_insert(tq, conn);
      return true1;
  }

  conn->flags = 0;

  int fd = lwan_connection_get_fd(tq->lwan, conn);

  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"
, 424, __FUNCTION__, "Couldn't spawn coroutine for file descriptor %d"
, fd);

  send_response_without_coro(tq->lwan, fd, HTTP_UNAVAILABLE);
  shutdown(fd, SHUT_RDWRSHUT_RDWR);
  close(fd);
  return false0;
430}

432static bool_Bool process_pending_timers(struct timeout_queue *tq,
                                 struct lwan_thread *t,
                                 int epoll_fd)
435{
  struct timeout *timeout;
  bool_Bool should_expire_timers = false0;

  while ((timeout = timeouts_get(t->wheel))) {
      struct lwan_request *request;

      if (timeout == &tq->timeout) {
          should_expire_timers = true1;
          continue;
      }

      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));

      update_epoll_flags(request->fd, request->conn, epoll_fd,
                         CONN_CORO_RESUME);
  }

  if (should_expire_timers) {
      timeout_queue_expire_waiting(tq);

      /* tq timeout expires every 1000ms if there are connections, so
       * update the date cache at this point as well.  */
      update_date_cache(t);

      if (!timeout_queue_empty(tq)) {
          timeouts_add(t->wheel, &tq->timeout, 1000);
          return true1;
      }

      timeouts_del(t->wheel, &tq->timeout);
  }

  return false0;
469}

471static int
472turn_timer_wheel(struct timeout_queue *tq, struct lwan_thread *t, int epoll_fd)
473{
  const int infinite_timeout = -1;
  timeout_t wheel_timeout;
  struct timespec now;

  if (UNLIKELY(clock_gettime(monotonic_clock_id, &now) < 0)__builtin_expect(((clock_gettime(monotonic_clock_id, &now
) < 0)), (0)))
      lwan_status_critical("Could not get monotonic time")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 479, __FUNCTION__, "Could not get monotonic time");

  timeouts_update(t->wheel,
                  (timeout_t)(now.tv_sec * 1000 + now.tv_nsec / 1000000));

  /* Check if there's an expired timer. */
  wheel_timeout = timeouts_timeout(t->wheel);
  if (wheel_timeout > 0) {
      return (int)wheel_timeout; /* No, but will soon. Wake us up in
                                    wheel_timeout ms. */
  }

  if (UNLIKELY((int64_t)wheel_timeout < 0)__builtin_expect((((int64_t)wheel_timeout < 0)), (0)))
      return infinite_timeout; /* None found. */

  if (!process_pending_timers(tq, t, epoll_fd))
      return infinite_timeout; /* No more timers to process. */

  /* After processing pending timers, determine when to wake up. */
  return (int)timeouts_timeout(t->wheel);
499}

501static bool_Bool accept_waiting_clients(const struct lwan_thread *t)
502{
  const struct lwan_connection *conns = t->lwan->conns;

  while (true1) {
      int fd =
          accept4(t->listen_fd, NULL((void*)0), NULL((void*)0), SOCK_NONBLOCKSOCK_NONBLOCK | SOCK_CLOEXECSOCK_CLOEXEC);

      if (LIKELY(fd >= 0)__builtin_expect((!!(fd >= 0)), (1))) {
          const struct lwan_connection *conn = &conns[fd];
          struct epoll_event ev = {
              .data.ptr = (void *)conn,
              .events = conn_flags_to_epoll_events(CONN_EVENTS_READ),
          };
          int r = epoll_ctl(conn->thread->epoll_fd, EPOLL_CTL_ADD1, fd, &ev);

          if (UNLIKELY(r < 0)__builtin_expect(((r < 0)), (0))) {
              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"
, 520, __FUNCTION__, "Could not add file descriptor %d to epoll "
 "set %d. Dropping connection", fd, conn->thread->epoll_fd
)
                                 "set %d. Dropping connection",lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 520, __FUNCTION__, "Could not add file descriptor %d to epoll "
 "set %d. Dropping connection", fd, conn->thread->epoll_fd
)
                                 fd, conn->thread->epoll_fd)lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 520, __FUNCTION__, "Could not add file descriptor %d to epoll "
 "set %d. Dropping connection", fd, conn->thread->epoll_fd
);

              send_response_without_coro(t->lwan, fd, HTTP_UNAVAILABLE);
              shutdown(fd, SHUT_RDWRSHUT_RDWR);
              close(fd);
          }

          continue;
      }

      switch (errno(*__errno_location ())) {
      default:
          lwan_status_perror("Unexpected error while accepting connections")lwan_status_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 532, __FUNCTION__, "Unexpected error while accepting connections"
);
          /* fallthrough */

      case EAGAIN11:
          return true1;

      case EBADF9:
      case ECONNABORTED103:
      case EINVAL22:
          lwan_status_info("Listening socket closed")lwan_status_info_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 541, __FUNCTION__, "Listening socket closed");
          return false0;
      }
  }

  __builtin_unreachable();
547}

549static int create_listen_socket(struct lwan_thread *t,
                              unsigned int num)
551{
  int listen_fd;

  listen_fd = lwan_create_listen_socket(t->lwan, num == 0);
  if (listen_fd < 0)
      lwan_status_critical("Could not create listen_fd")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 556, __FUNCTION__, "Could not create listen_fd");

   /* Ignore errors here, as this is just a hint */
559#if defined(HAVE_SO_ATTACH_REUSEPORT_CBPF)
  /* From socket(7): "These  options may be set repeatedly at any time on
   * any socket in the group to replace the current BPF program used by
   * all sockets in the group." */
  if (num == 0) {
      /* From socket(7): "The  BPF program must return an index between 0 and
       * N-1 representing the socket which should receive the packet (where N
       * is the number of sockets in the group)." */
      const uint32_t cpu_ad_off = (uint32_t)SKF_AD_OFF(-0x1000) + SKF_AD_CPU36;
      struct sock_filter filter[] = {
          {BPF_LD0x00 | BPF_W0x00 | BPF_ABS0x20, 0, 0, cpu_ad_off},   /* A = curr_cpu_index */
          {BPF_RET0x06 | BPF_A0x10, 0, 0, 0},                     /* return A */
      };
      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]))};

      (void)setsockopt(listen_fd, SOL_SOCKET1, SO_ATTACH_REUSEPORT_CBPF51,
                       &fprog, sizeof(fprog));
      (void)setsockopt(listen_fd, SOL_SOCKET1, SO_LOCK_FILTER44,
                       (int[]){1}, sizeof(int));
  }
579#elif defined(HAVE_SO_INCOMING_CPU) && defined(__x86_64__1)
  (void)setsockopt(listen_fd, SOL_SOCKET1, SO_INCOMING_CPU49, &t->cpu,
                   sizeof(t->cpu));
582#endif

  struct epoll_event event = {
      .events = EPOLLINEPOLLIN | EPOLLETEPOLLET | EPOLLERREPOLLERR,
      .data.ptr = NULL((void*)0),
  };
  if (epoll_ctl(t->epoll_fd, EPOLL_CTL_ADD1, listen_fd, &event) < 0)
      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"
, 589, __FUNCTION__, "Could not add socket to epoll");

  return listen_fd;
592}

594static void *thread_io_loop(void *data)
595{
  struct lwan_thread *t = data;
  int epoll_fd = t->epoll_fd;
  const int max_events = LWAN_MIN((int)t->lwan->thread.max_fd, 1024)({ const __typeof__(((int)t->lwan->thread.max_fd) + 0) lwan_tmp_id6
 = ((int)t->lwan->thread.max_fd); const __typeof__((1024
) + 0) lwan_tmp_id7 = (1024); lwan_tmp_id6 > lwan_tmp_id7 ?
 lwan_tmp_id7 : lwan_tmp_id6; });
  struct lwan *lwan = t->lwan;
  struct epoll_event *events;
  struct coro_switcher switcher;
  struct timeout_queue tq;

  lwan_status_debug("Worker thread #%zd starting",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 605, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1)
                    t - t->lwan->thread.threads + 1)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 605, __FUNCTION__, "Worker thread #%zd starting", t - t->
lwan->thread.threads + 1);
  lwan_set_thread_name("worker");

  events = calloc((size_t)max_events, sizeof(*events));
  if (UNLIKELY(!events)__builtin_expect(((!events)), (0)))
      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"
, 610, __FUNCTION__, "Could not allocate memory for events");

  update_date_cache(t);

  timeout_queue_init(&tq, lwan);

  lwan_random_seed_prng_for_thread(t);

  pthread_barrier_wait(&lwan->thread.barrier);

  for (;;) {
      int timeout = turn_timer_wheel(&tq, t, epoll_fd);
      int n_fds = epoll_wait(epoll_fd, events, max_events, timeout);
      bool_Bool accepted_connections = false0;

      if (UNLIKELY(n_fds < 0)__builtin_expect(((n_fds < 0)), (0))) {
          if (errno(*__errno_location ()) == EBADF9 || errno(*__errno_location ()) == EINVAL22)
              break;
          continue;
      }

      for (struct epoll_event *event = events; n_fds--; event++) {
          struct lwan_connection *conn;

          if (!event->data.ptr) {
              if (LIKELY(accept_waiting_clients(t))__builtin_expect((!!(accept_waiting_clients(t))), (1))) {
                  accepted_connections = true1;
                  continue;
              }
              close(epoll_fd);
              epoll_fd = -1;
              break;
          }

          conn = event->data.ptr;

          if (UNLIKELY(event->events & (EPOLLRDHUP | EPOLLHUP))__builtin_expect(((event->events & (EPOLLRDHUP | EPOLLHUP
))), (0))) {
              timeout_queue_expire(&tq, conn);
              continue;
          }

          if (!conn->coro) {
              if (UNLIKELY(!spawn_coro(conn, &switcher, &tq))__builtin_expect(((!spawn_coro(conn, &switcher, &tq))
), (0)))
                  continue;
          }

          resume_coro(&tq, conn, epoll_fd);
          timeout_queue_move_to_last(&tq, conn);
      }

      if (accepted_connections)
          timeouts_add(t->wheel, &tq.timeout, 1000);
  }

  pthread_barrier_wait(&lwan->thread.barrier);

  timeout_queue_expire_all(&tq);
  free(events);

  return NULL((void*)0);
670}

672static void create_thread(struct lwan *l, struct lwan_thread *thread)
673{
  int ignore;
  pthread_attr_t attr;

  thread->lwan = l;

  thread->wheel = timeouts_open(&ignore);
  if (!thread->wheel)
      lwan_status_critical("Could not create timer wheel")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 681, __FUNCTION__, "Could not create timer wheel");

  if ((thread->epoll_fd = epoll_create1(EPOLL_CLOEXECEPOLL_CLOEXEC)) < 0)
      lwan_status_critical_perror("epoll_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 684, __FUNCTION__, "epoll_create");

  if (pthread_attr_init(&attr))
      lwan_status_critical_perror("pthread_attr_init")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 687, __FUNCTION__, "pthread_attr_init");

  if (pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEMPTHREAD_SCOPE_SYSTEM))
      lwan_status_critical_perror("pthread_attr_setscope")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 690, __FUNCTION__, "pthread_attr_setscope");

  if (pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLEPTHREAD_CREATE_JOINABLE))
      lwan_status_critical_perror("pthread_attr_setdetachstate")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 693, __FUNCTION__, "pthread_attr_setdetachstate");

  if (pthread_create(&thread->self, &attr, thread_io_loop, thread))
      lwan_status_critical_perror("pthread_create")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 696, __FUNCTION__, "pthread_create");

  if (pthread_attr_destroy(&attr))
      lwan_status_critical_perror("pthread_attr_destroy")lwan_status_critical_perror_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 699, __FUNCTION__, "pthread_attr_destroy");
700}

702#if defined(__linux__1) && defined(__x86_64__1)
703static bool_Bool read_cpu_topology(struct lwan *l, uint32_t siblings[])
704{
  char path[PATH_MAX4096];

  for (uint32_t i = 0; i < l->available_cpus; i++)
      siblings[i] = 0xbebacafe;

  for (unsigned int i = 0; i < l->available_cpus; i++) {
      FILE *sib;
      uint32_t id, sibling;
      char separator;

      snprintf(path, sizeof(path),
               "/sys/devices/system/cpu/cpu%d/topology/thread_siblings_list",
               i);

      sib = fopen(path, "re");
      if (!sib) {
          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"
, 722, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path)
                              path)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 722, __FUNCTION__, "Could not open `%s` to determine CPU topology"
, path);
          return false0;
      }

      switch (fscanf(sib, "%u%c%u", &id, &separator, &sibling)) {
      case 2: /* No SMT */
          siblings[i] = id;
          break;
      case 3: /* SMT */
          if (!(separator == ',' || separator == '-')) {
              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"
, 732, __FUNCTION__, "Expecting either ',' or '-' for sibling separator"
);
              __builtin_unreachable();
          }

          siblings[i] = sibling;
          break;
      default:
          lwan_status_critical("%s has invalid format", path)lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 739, __FUNCTION__, "%s has invalid format", path);
          __builtin_unreachable();
      }

      fclose(sib);
  }

  /* Perform a sanity check here, as some systems seem to filter out the
   * result of sysconf() to obtain the number of configured and online
   * CPUs but don't bother changing what's available through sysfs as far
   * as the CPU topology information goes.  It's better to fall back to a
   * possibly non-optimal setup than just crash during startup while
   * trying to perform an out-of-bounds array access.  */
  for (unsigned int i = 0; i < l->available_cpus; i++) {
      if (siblings[i] == 0xbebacafe) {
          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"
, 754, __FUNCTION__, "Could not determine sibling for CPU %d"
, i);
          return false0;
      }

      if (siblings[i] >= l->available_cpus) {
          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"
, 762, __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)
                              "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"
, 762, __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)
                              "Is Lwan running in a (broken) container?",lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 762, __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)
                              siblings[i], l->available_cpus, l->online_cpus)lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 762, __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);
          return false0;
      }
  }

  return true1;
768}

770static void
771siblings_to_schedtbl(struct lwan *l, uint32_t siblings[], uint32_t schedtbl[])
772{
  int *seen = alloca(l->available_cpus * sizeof(int))__builtin_alloca (l->available_cpus * sizeof(int));
  unsigned int n_schedtbl = 0;

  for (uint32_t i = 0; i < l->available_cpus; i++)
      seen[i] = -1;

  for (uint32_t i = 0; i < l->available_cpus; i++) {
      if (seen[siblings[i]] < 0) {
          seen[siblings[i]] = (int)i;
      } else {
          schedtbl[n_schedtbl++] = (uint32_t)seen[siblings[i]];
          schedtbl[n_schedtbl++] = i;
      }
  }

  if (n_schedtbl != l->available_cpus)
      memcpy(schedtbl, seen, l->available_cpus * sizeof(int));
790}

792static bool_Bool
793topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
794{
  uint32_t *siblings = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));

  if (read_cpu_topology(l, siblings)) {
6
←
Assuming the condition is false→
7
←
Taking false branch→
      uint32_t *affinity = alloca(l->available_cpus * sizeof(uint32_t))__builtin_alloca (l->available_cpus * sizeof(uint32_t));

      siblings_to_schedtbl(l, siblings, affinity);

      for (uint32_t i = 0; i < n_threads; i++)
          schedtbl[i] = affinity[i % l->available_cpus];
      return true1;
  }

  for (uint32_t i = 0; i < n_threads; i++)
8
←
Assuming 'i' is >= 'n_threads'→
9
←
Loop condition is false. Execution continues on line 809→
      schedtbl[i] = (i / 2) % l->thread.count;
  return false0;
10
←
Returning without writing to '*schedtbl'→
810}

812static void
813adjust_thread_affinity(const struct lwan_thread *thread)
814{
  cpu_set_t set;

  CPU_ZERO(&set)do __builtin_memset (&set, '\0', sizeof (cpu_set_t)); while
 (0);
  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; }));

  if (pthread_setaffinity_np(thread->self, sizeof(set), &set))
      lwan_status_warning("Could not set thread affinity")lwan_status_warning_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 821, __FUNCTION__, "Could not set thread affinity");
822}
823#elif defined(__x86_64__1)
824static bool_Bool
825topology_to_schedtbl(struct lwan *l, uint32_t schedtbl[], uint32_t n_threads)
826{
  for (uint32_t i = 0; i < n_threads; i++)
      schedtbl[i] = (i / 2) % l->thread.count;
  return false0;
830}

832static void
833adjust_thread_affinity(const struct lwan_thread *thread)
834{
  (void)thread;
836}
837#endif

839void lwan_thread_init(struct lwan *l)
840{
  const unsigned int total_conns = l->thread.max_fd * l->thread.count;

  lwan_status_debug("Initializing threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 843, __FUNCTION__, "Initializing threads");

  l->thread.threads =
      calloc((size_t)l->thread.count, sizeof(struct lwan_thread));
  if (!l->thread.threads)
1
Assuming field 'threads' is non-null→
2
←
Taking false branch→
      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"
, 848, __FUNCTION__, "Could not allocate memory for threads");

850#ifdef __x86_64__1
  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; })]
                "Two connections per cache line")extern int (*__Static_assert_function (void)) [!!sizeof (struct
 { int __error_if_negative: (sizeof(struct lwan_connection) ==
 32) ? 2 : -1; })];
853#ifdef _SC_LEVEL1_DCACHE_LINESIZE_SC_LEVEL1_DCACHE_LINESIZE
  assert(sysconf(_SC_LEVEL1_DCACHE_LINESIZE) == 64)((void) sizeof ((sysconf(_SC_LEVEL1_DCACHE_LINESIZE) == 64) ?
: 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"
, 854, __extension__ __PRETTY_FUNCTION__); }));
3
←
Assuming the condition is true→
4
←
Taking true branch→
855#endif

  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"
, 859, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
                    "Reading topology to pre-schedule clients",lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 859, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus)
                    l->online_cpus, l->available_cpus)lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 859, __FUNCTION__, "%d CPUs of %d are online. " "Reading topology to pre-schedule clients"
, l->online_cpus, l->available_cpus);

  /*
   * Pre-schedule each file descriptor, to reduce some operations in the
   * fast path.
   *
   * Since struct lwan_connection is guaranteed to be 32-byte long, two of
   * them can fill up a cache line.  Assume siblings share cache lines and
   * use the CPU topology to group two connections per cache line in such
   * a way that false sharing is avoided.
   */
  uint32_t n_threads =
      (uint32_t)lwan_nextpow2((size_t)((l->thread.count - 1) * 2));
  uint32_t *schedtbl = alloca(n_threads * sizeof(uint32_t))__builtin_alloca (n_threads * sizeof(uint32_t));

  bool_Bool adj_affinity = topology_to_schedtbl(l, schedtbl, n_threads);
5
←
Calling 'topology_to_schedtbl'→
11
←
Returning from 'topology_to_schedtbl'→

  n_threads--; /* Transform count into mask for AND below */

  for (unsigned int i = 0; i < total_conns; i++)
12
←
Assuming 'i' is >= 'total_conns'→
13
←
Loop condition is false. Execution continues on line 890→
      l->conns[i].thread = &l->thread.threads[schedtbl[i & n_threads]];
880#else
  for (unsigned int i = 0; i < l->thread.count; i++)
      l->thread.threads[i].cpu = i % l->online_cpus;
  for (unsigned int i = 0; i < total_conns; i++)
      l->conns[i].thread = &l->thread.threads[i % l->thread.count];

  uint32_t *schedtbl = NULL((void*)0);
  const bool_Bool adj_affinity = false0;
888#endif

  for (unsigned int i = 0; i < l->thread.count; i++) {
14
←
Assuming 'i' is < field 'count'→
15
←
Loop condition is true.  Entering loop body→
      struct lwan_thread *thread = NULL((void*)0);

      if (schedtbl15.1
'schedtbl' is non-null
) {
16
←
Taking true branch→
          /* This is not the most elegant thing, but this assures that the
           * listening sockets are added to the SO_REUSEPORT group in a
           * specific order, because that's what the CBPF program to direct
           * the incoming connection to the right CPU will use. */
          for (uint32_t thread_id = 0; thread_id16.1
'thread_id' is < field 'count'
 < l->thread.count;
17
←
Loop condition is true.  Entering loop body→
               thread_id++) {
              if (schedtbl[thread_id & n_threads] == i) {
18
←
The left operand of '==' is a garbage value
                  thread = &l->thread.threads[thread_id];
                  break;
              }
          }
          if (!thread) {
              /* FIXME: can this happen when we have a offline CPU? */
              lwan_status_critical(lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 908, __FUNCTION__, "Could not figure out which CPU thread %d should go to"
, i)
                  "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"
, 908, __FUNCTION__, "Could not figure out which CPU thread %d should go to"
, i);
          }
      } else {
          thread = &l->thread.threads[i % l->thread.count];
      }

      if (pthread_barrier_init(&l->thread.barrier, NULL((void*)0), 2))
          lwan_status_critical("Could not create barrier")lwan_status_critical_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 915, __FUNCTION__, "Could not create barrier");

      create_thread(l, thread);

      if ((thread->listen_fd = create_listen_socket(thread, i)) < 0)
          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"
, 920, __FUNCTION__, "Could not create listening socket");

      if (adj_affinity) {
          l->thread.threads[i].cpu = schedtbl[i & n_threads];
          adjust_thread_affinity(thread);
      }

      pthread_barrier_wait(&l->thread.barrier);
  }

  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"
, 930, __FUNCTION__, "Worker threads created and ready to serve"
);
931}

933void lwan_thread_shutdown(struct lwan *l)
934{
  lwan_status_debug("Shutting down threads")lwan_status_debug_debug("/home/buildbot/lwan-worker/clang-analyze/build/src/lib/lwan-thread.c"
, 935, __FUNCTION__, "Shutting down threads");

  for (unsigned int i = 0; i < l->thread.count; i++) {
      struct lwan_thread *t = &l->thread.threads[i];
      int epoll_fd = t->epoll_fd;
      int listen_fd = t->listen_fd;

      t->listen_fd = -1;
      t->epoll_fd = -1;
      close(epoll_fd);
      close(listen_fd);
  }

  pthread_barrier_wait(&l->thread.barrier);
  pthread_barrier_destroy(&l->thread.barrier);

  for (unsigned int i = 0; i < l->thread.count; i++) {
      struct lwan_thread *t = &l->thread.threads[i];

      pthread_join(l->thread.threads[i].self, NULL((void*)0));
      timeouts_close(t->wheel);
  }

  free(l->thread.threads);
959}