src/patches/dnsmasq/0058-Fix-boilerplate-code-for-re-running-system-calls-on-.patch

   1 From ff841ebf5a5d6864ff48571f607c32ce80dbb75a Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Wed, 11 Mar 2015 21:36:30 +0000
   4 Subject: [PATCH 58/71] Fix boilerplate code for re-running system calls on
   5  EINTR and EAGAIN etc.
   6
   7 The nasty code with static variable in retry_send() which
   8 avoids looping forever needs to be called on success of the syscall,
   9 to reset the static variable.
  10 ---
  11  src/bpf.c     |  2 +-
  12  src/dhcp.c    |  2 +-
  13  src/dhcp6.c   |  6 +++---
  14  src/dnsmasq.c | 35 +++++++++++++++++----------------
  15  src/dnsmasq.h |  2 +-
  16  src/forward.c | 41 ++++++++++++++++++--------------------
  17  src/ipset.c   |  8 ++++----
  18  src/loop.c    |  5 +++--
  19  src/netlink.c |  8 ++++----
  20  src/radv.c    |  5 +++--
  21  src/util.c    | 63 ++++++++++++++++++++++++++++++++++-------------------------
  22  11 files changed, 93 insertions(+), 84 deletions(-)
  23
  24 diff --git a/src/bpf.c b/src/bpf.c
  25 index 997d87421bed..a066641f969f 100644
  26 --- a/src/bpf.c
  27 +++ b/src/bpf.c
  28 @@ -359,7 +359,7 @@ void send_via_bpf(struct dhcp_packet *mess, size_t len,
  29    iov[3].iov_base = mess;
  30    iov[3].iov_len = len;
  31
  32 -  while (writev(daemon->dhcp_raw_fd, iov, 4) == -1 && retry_send());
  33 +  while (retry_send(writev(daemon->dhcp_raw_fd, iov, 4)));
  34  }
  35
  36  #endif /* defined(HAVE_BSD_NETWORK) && defined(HAVE_DHCP) */
  37 diff --git a/src/dhcp.c b/src/dhcp.c
  38 index f29be9b489a7..5c3089ab94ff 100644
  39 --- a/src/dhcp.c
  40 +++ b/src/dhcp.c
  41 @@ -443,7 +443,7 @@ void dhcp_packet(time_t now, int pxe_fd)
  42    setsockopt(fd, IPPROTO_IP, IP_BOUND_IF, &iface_index, sizeof(iface_index));
  43  #endif
  44
  45 -  while(sendmsg(fd, &msg, 0) == -1 && retry_send());
  46 +  while(retry_send(sendmsg(fd, &msg, 0)));
  47  }
  48
  49  /* check against secondary interface addresses */
  50 diff --git a/src/dhcp6.c b/src/dhcp6.c
  51 index c7144f5fee7c..ee2aa5d3bf3c 100644
  52 --- a/src/dhcp6.c
  53 +++ b/src/dhcp6.c
  54 @@ -225,9 +225,9 @@ void dhcp6_packet(time_t now)
  55    if (port != 0)
  56      {
  57        from.sin6_port = htons(port);
  58 -      while (sendto(daemon->dhcp6fd, daemon->outpacket.iov_base, save_counter(0),
  59 -                   0, (struct sockaddr *)&from, sizeof(from)) == -1 &&
  60 -          retry_send());
  61 +      while (retry_send(sendto(daemon->dhcp6fd, daemon->outpacket.iov_base,
  62 +                              save_counter(0), 0, (struct sockaddr *)&from,
  63 +                              sizeof(from))));
  64      }
  65  }
  66
  67 diff --git a/src/dnsmasq.c b/src/dnsmasq.c
  68 index f3e5bcffec4f..b784951950d4 100644
  69 --- a/src/dnsmasq.c
  70 +++ b/src/dnsmasq.c
  71 @@ -444,7 +444,7 @@ int main (int argc, char **argv)
  72               char *msg;
  73
  74               /* close our copy of write-end */
  75 -             close(err_pipe[1]);
  76 +             while (retry_send(close(err_pipe[1])));
  77
  78               /* check for errors after the fork */
  79               if (read_event(err_pipe[0], &ev, &msg))
  80 @@ -453,7 +453,7 @@ int main (int argc, char **argv)
  81               _exit(EC_GOOD);
  82             }
  83
  84 -         close(err_pipe[0]);
  85 +         while (retry_send(close(err_pipe[0])));
  86
  87           /* NO calls to die() from here on. */
  88
  89 @@ -505,10 +505,12 @@ int main (int argc, char **argv)
  90             {
  91               if (!read_write(fd, (unsigned char *)daemon->namebuff, strlen(daemon->namebuff), 0))
  92                 err = 1;
  93 -
  94 -             while (!err && close(fd) == -1)
  95 -               if (!retry_send())
  96 -                 err = 1;
  97 +             else
  98 +               {
  99 +                 while (retry_send(close(fd)));
 100 +                 if (errno != 0)
 101 +                   err = 1;
 102 +               }
 103             }
 104
 105           if (err)
 106 @@ -813,7 +815,7 @@ int main (int argc, char **argv)
 107
 108    /* finished start-up - release original process */
 109    if (err_pipe[1] != -1)
 110 -    close(err_pipe[1]);
 111 +    while (retry_send(close(err_pipe[1])));
 112
 113    if (daemon->port != 0)
 114      check_servers();
 115 @@ -1319,7 +1321,7 @@ static void async_event(int pipe, time_t now)
 116             do {
 117               helper_write();
 118             } while (!helper_buf_empty() || do_script_run(now));
 119 -           close(daemon->helperfd);
 120 +           while (retry_send(close(daemon->helperfd)));
 121           }
 122  #endif
 123
 124 @@ -1544,7 +1546,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 125
 126           if (getsockname(confd, (struct sockaddr *)&tcp_addr, &tcp_len) == -1)
 127             {
 128 -             close(confd);
 129 +             while (retry_send(close(confd)));
 130               continue;
 131             }
 132
 133 @@ -1609,7 +1611,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 134           if (!client_ok)
 135             {
 136               shutdown(confd, SHUT_RDWR);
 137 -             close(confd);
 138 +             while (retry_send(close(confd)));
 139             }
 140  #ifndef NO_FORK
 141           else if (!option_bool(OPT_DEBUG) && (p = fork()) != 0)
 142 @@ -1624,7 +1626,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 143                         break;
 144                       }
 145                 }
 146 -             close(confd);
 147 +             while (retry_send(close(confd)));
 148
 149               /* The child can use up to TCP_MAX_QUERIES ids, so skip that many. */
 150               daemon->log_id += TCP_MAX_QUERIES;
 151 @@ -1669,7 +1671,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 152               buff = tcp_request(confd, now, &tcp_addr, netmask, auth_dns);
 153
 154               shutdown(confd, SHUT_RDWR);
 155 -             close(confd);
 156 +             while (retry_send(close(confd)));
 157
 158               if (buff)
 159                 free(buff);
 160 @@ -1678,7 +1680,7 @@ static void check_dns_listeners(fd_set *set, time_t now)
 161                 if (s->tcpfd != -1)
 162                   {
 163                     shutdown(s->tcpfd, SHUT_RDWR);
 164 -                   close(s->tcpfd);
 165 +                   while (retry_send(close(s->tcpfd)));
 166                   }
 167  #ifndef NO_FORK
 168               if (!option_bool(OPT_DEBUG))
 169 @@ -1756,9 +1758,8 @@ int icmp_ping(struct in_addr addr)
 170      j = (j & 0xffff) + (j >> 16);
 171    packet.icmp.icmp_cksum = (j == 0xffff) ? j : ~j;
 172
 173 -  while (sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0,
 174 -               (struct sockaddr *)&saddr, sizeof(saddr)) == -1 &&
 175 -        retry_send());
 176 +  while (retry_send(sendto(fd, (char *)&packet.icmp, sizeof(struct icmp), 0,
 177 +                          (struct sockaddr *)&saddr, sizeof(saddr))));
 178
 179    for (now = start = dnsmasq_time();
 180         difftime(now, start) < (float)PING_WAIT;)
 181 @@ -1820,7 +1821,7 @@ int icmp_ping(struct in_addr addr)
 182      }
 183
 184  #if defined(HAVE_LINUX_NETWORK) || defined(HAVE_SOLARIS_NETWORK)
 185 -  close(fd);
 186 +  while (retry_send(close(fd)));
 187  #else
 188    opt = 1;
 189    setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt));
 190 diff --git a/src/dnsmasq.h b/src/dnsmasq.h
 191 index fc7259881358..de95d0e875e3 100644
 192 --- a/src/dnsmasq.h
 193 +++ b/src/dnsmasq.h
 194 @@ -1177,7 +1177,7 @@ int is_same_net6(struct in6_addr *a, struct in6_addr *b, int prefixlen);
 195  u64 addr6part(struct in6_addr *addr);
 196  void setaddr6part(struct in6_addr *addr, u64 host);
 197  #endif
 198 -int retry_send(void);
 199 +int retry_send(ssize_t rc);
 200  void prettyprint_time(char *buf, unsigned int t);
 201  int prettyprint_addr(union mysockaddr *addr, char *buf);
 202  int parse_hex(char *in, unsigned char *out, int maxlen,
 203 diff --git a/src/forward.c b/src/forward.c
 204 index 438e9fa490b8..7c0fa8da3fdf 100644
 205 --- a/src/forward.c
 206 +++ b/src/forward.c
 207 @@ -103,15 +103,11 @@ int send_from(int fd, int nowild, char *packet, size_t len,
 208  #endif
 209      }
 210
 211 -  while (sendmsg(fd, &msg, 0) == -1)
 212 +  while (retry_send(sendmsg(fd, &msg, 0)));
 213 +
 214 +  /* If interface is still in DAD, EINVAL results - ignore that. */
 215 +  if (errno != 0 && errno != EINVAL)
 216      {
 217 -      if (retry_send())
 218 -       continue;
 219 -
 220 -      /* If interface is still in DAD, EINVAL results - ignore that. */
 221 -      if (errno == EINVAL)
 222 -       break;
 223 -
 224        my_syslog(LOG_ERR, _("failed to send packet: %s"), strerror(errno));
 225        return 0;
 226      }
 227 @@ -297,9 +293,9 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 228                 fd = forward->rfd4->fd;
 229             }
 230
 231 -         while (sendto(fd, (char *)header, plen, 0,
 232 -                       &forward->sentto->addr.sa,
 233 -                       sa_len(&forward->sentto->addr)) == -1 && retry_send());
 234 +         while (retry_send( sendto(fd, (char *)header, plen, 0,
 235 +                                   &forward->sentto->addr.sa,
 236 +                                   sa_len(&forward->sentto->addr))));
 237
 238           return 1;
 239         }
 240 @@ -469,14 +465,12 @@ static int forward_query(int udpfd, union mysockaddr *udpaddr,
 241  #endif
 242                 }
 243
 244 -             if (sendto(fd, (char *)header, plen, 0,
 245 -                        &start->addr.sa,
 246 -                        sa_len(&start->addr)) == -1)
 247 -               {
 248 -                 if (retry_send())
 249 -                   continue;
 250 -               }
 251 -             else
 252 +             if (retry_send(sendto(fd, (char *)header, plen, 0,
 253 +                                   &start->addr.sa,
 254 +                                   sa_len(&start->addr))))
 255 +               continue;
 256 +
 257 +             if (errno == 0)
 258                 {
 259                   /* Keep info in case we want to re-send this packet */
 260                   daemon->srv_save = start;
 261 @@ -932,7 +926,9 @@ void reply_query(int fd, int family, time_t now)
 262
 263                   if (fd != -1)
 264                     {
 265 -                     while (sendto(fd, (char *)header, nn, 0, &server->addr.sa, sa_len(&server->addr)) == -1 && retry_send());
 266 +                     while (retry_send(sendto(fd, (char *)header, nn, 0,
 267 +                                              &server->addr.sa,
 268 +                                              sa_len(&server->addr))));
 269                       server->queries++;
 270                     }
 271
 272 @@ -2228,8 +2224,9 @@ void resend_query()
 273        else
 274         return;
 275
 276 -      while(sendto(fd, daemon->packet, daemon->packet_len, 0,
 277 -                  &daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
 278 +      while(retry_send(sendto(fd, daemon->packet, daemon->packet_len, 0,
 279 +                             &daemon->srv_save->addr.sa,
 280 +                             sa_len(&daemon->srv_save->addr))));
 281      }
 282  }
 283
 284 diff --git a/src/ipset.c b/src/ipset.c
 285 index 8c5b72722371..a315e86bc7f4 100644
 286 --- a/src/ipset.c
 287 +++ b/src/ipset.c
 288 @@ -121,7 +121,6 @@ static int new_add_to_ipset(const char *setname, const struct all_addr *ipaddr,
 289    struct my_nlattr *nested[2];
 290    uint8_t proto;
 291    int addrsz = INADDRSZ;
 292 -  ssize_t rc;
 293
 294  #ifdef HAVE_IPV6
 295    if (af == AF_INET6)
 296 @@ -162,9 +161,10 @@ static int new_add_to_ipset(const char *setname, const struct all_addr *ipaddr,
 297    nested[1]->nla_len = (void *)buffer + NL_ALIGN(nlh->nlmsg_len) - (void *)nested[1];
 298    nested[0]->nla_len = (void *)buffer + NL_ALIGN(nlh->nlmsg_len) - (void *)nested[0];
 299
 300 -  while ((rc = sendto(ipset_sock, buffer, nlh->nlmsg_len, 0,
 301 -                     (struct sockaddr *)&snl, sizeof(snl))) == -1 && retry_send());
 302 -  return rc;
 303 +  while (retry_send(sendto(ipset_sock, buffer, nlh->nlmsg_len, 0,
 304 +                          (struct sockaddr *)&snl, sizeof(snl))));
 305 +
 306 +  return errno == 0 ? 0 : -1;
 307  }
 308
 309
 310 diff --git a/src/loop.c b/src/loop.c
 311 index 565f7d8e58e0..c9ed075670de 100644
 312 --- a/src/loop.c
 313 +++ b/src/loop.c
 314 @@ -45,8 +45,9 @@ void loop_send_probes()
 315              fd = rfd->fd;
 316            }
 317
 318 -        while (sendto(fd, daemon->packet, len, 0, &serv->addr.sa, sa_len(&serv->addr)) == -1 && retry_send());
 319 -
 320 +        while (retry_send(sendto(fd, daemon->packet, len, 0,
 321 +                                 &serv->addr.sa, sa_len(&serv->addr))));
 322 +
 323          free_rfd(rfd);
 324         }
 325  }
 326 diff --git a/src/netlink.c b/src/netlink.c
 327 index 10f94db25a14..753784dc20b4 100644
 328 --- a/src/netlink.c
 329 +++ b/src/netlink.c
 330 @@ -169,10 +169,10 @@ int iface_enumerate(int family, void *parm, int (*callback)())
 331    req.g.rtgen_family = family;
 332
 333    /* Don't block in recvfrom if send fails */
 334 -  while((len = sendto(daemon->netlinkfd, (void *)&req, sizeof(req), 0,
 335 -                     (struct sockaddr *)&addr, sizeof(addr))) == -1 && retry_send());
 336 -
 337 -  if (len == -1)
 338 +  while(retry_send(sendto(daemon->netlinkfd, (void *)&req, sizeof(req), 0,
 339 +                         (struct sockaddr *)&addr, sizeof(addr))));
 340 +
 341 +  if (errno != 0)
 342      return 0;
 343
 344    while (1)
 345 diff --git a/src/radv.c b/src/radv.c
 346 index 6da125b864ae..d0faddf8684a 100644
 347 --- a/src/radv.c
 348 +++ b/src/radv.c
 349 @@ -479,8 +479,9 @@ static void send_ra(time_t now, int iface, char *iface_name, struct in6_addr *de
 350        setsockopt(daemon->icmp6fd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &iface, sizeof(iface));
 351      }
 352
 353 -  while (sendto(daemon->icmp6fd, daemon->outpacket.iov_base, save_counter(0), 0,
 354 -               (struct sockaddr *)&addr, sizeof(addr)) == -1 && retry_send());
 355 +  while (retry_send(sendto(daemon->icmp6fd, daemon->outpacket.iov_base,
 356 +                          save_counter(0), 0, (struct sockaddr *)&addr,
 357 +                          sizeof(addr))));
 358
 359  }
 360
 361 diff --git a/src/util.c b/src/util.c
 362 index 91d02410b13f..648bc4d4b428 100644
 363 --- a/src/util.c
 364 +++ b/src/util.c
 365 @@ -569,17 +569,27 @@ void bump_maxfd(int fd, int *max)
 366      *max = fd;
 367  }
 368
 369 -int retry_send(void)
 370 +/* rc is return from sendto and friends.
 371 +   Return 1 if we should retry.
 372 +   Set errno to zero if we succeeded. */
 373 +int retry_send(ssize_t rc)
 374  {
 375 +  static int retries = 0;
 376 +  struct timespec waiter;
 377 +
 378 +  if (rc != -1)
 379 +    {
 380 +      retries = 0;
 381 +      errno = 0;
 382 +      return 0;
 383 +    }
 384 +
 385    /* Linux kernels can return EAGAIN in perpetuity when calling
 386       sendmsg() and the relevant interface has gone. Here we loop
 387       retrying in EAGAIN for 1 second max, to avoid this hanging
 388       dnsmasq. */
 389
 390 -  static int retries = 0;
 391 -  struct timespec waiter;
 392 -
 393 -   if (errno == EAGAIN || errno == EWOULDBLOCK)
 394 +  if (errno == EAGAIN || errno == EWOULDBLOCK)
 395       {
 396         waiter.tv_sec = 0;
 397         waiter.tv_nsec = 10000;
 398 @@ -587,13 +597,13 @@ int retry_send(void)
 399         if (retries++ < 1000)
 400          return 1;
 401       }
 402 -
 403 -   retries = 0;
 404 -
 405 -   if (errno == EINTR)
 406 -     return 1;
 407 -
 408 -   return 0;
 409 +
 410 +  retries = 0;
 411 +
 412 +  if (errno == EINTR)
 413 +    return 1;
 414 +
 415 +  return 0;
 416  }
 417
 418  int read_write(int fd, unsigned char *packet, int size, int rw)
 419 @@ -602,22 +612,21 @@ int read_write(int fd, unsigned char *packet, int size, int rw)
 420
 421    for (done = 0; done < size; done += n)
 422      {
 423 -    retry:
 424 -      if (rw)
 425 -        n = read(fd, &packet[done], (size_t)(size - done));
 426 -      else
 427 -        n = write(fd, &packet[done], (size_t)(size - done));
 428 -
 429 -      if (n == 0)
 430 -        return 0;
 431 -      else if (n == -1)
 432 -        {
 433 -          if (retry_send() || errno == ENOMEM || errno == ENOBUFS)
 434 -            goto retry;
 435 -          else
 436 -            return 0;
 437 -        }
 438 +      do {
 439 +       if (rw)
 440 +         n = read(fd, &packet[done], (size_t)(size - done));
 441 +       else
 442 +         n = write(fd, &packet[done], (size_t)(size - done));
 443 +
 444 +       if (n == 0)
 445 +         return 0;
 446 +
 447 +      } while (retry_send(n) || errno == ENOMEM || errno == ENOBUFS);
 448 +
 449 +      if (errno != 0)
 450 +       return 0;
 451      }
 452 +
 453    return 1;
 454  }
 455
 456 --
 457 2.1.0
 458