src/fd.cc

   1
   2 /*
   3  * $Id$
   4  *
   5  * DEBUG: section 51    Filedescriptor Functions
   6  * AUTHOR: Duane Wessels
   7  *
   8  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   9  * ----------------------------------------------------------
  10  *
  11  *  Squid is the result of efforts by numerous individuals from
  12  *  the Internet community; see the CONTRIBUTORS file for full
  13  *  details.   Many organizations have provided support for Squid's
  14  *  development; see the SPONSORS file for full details.  Squid is
  15  *  Copyrighted (C) 2001 by the Regents of the University of
  16  *  California; see the COPYRIGHT file for full details.  Squid
  17  *  incorporates software developed and/or copyrighted by other
  18  *  sources; see the CREDITS file for full details.
  19  *
  20  *  This program is free software; you can redistribute it and/or modify
  21  *  it under the terms of the GNU General Public License as published by
  22  *  the Free Software Foundation; either version 2 of the License, or
  23  *  (at your option) any later version.
  24  *
  25  *  This program is distributed in the hope that it will be useful,
  26  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  27  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  28  *  GNU General Public License for more details.
  29  *
  30  *  You should have received a copy of the GNU General Public License
  31  *  along with this program; if not, write to the Free Software
  32  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  33  *
  34  */
  35
  36 #include "squid.h"
  37 #include "comm/Loops.h"
  38 #include "fde.h"
  39 #include "SquidTime.h"
  40 #include "Debug.h"
  41
  42
  43 // Solaris and possibly others lack MSG_NOSIGNAL optimization
  44 // TODO: move this into compat/? Use a dedicated compat file to avoid dragging
  45 // sys/types.h and sys/socket.h into the rest of Squid??
  46 #ifndef MSG_NOSIGNAL
  47 #define MSG_NOSIGNAL 0
  48 #endif
  49
  50 int default_read_method(int, char *, int);
  51 int default_write_method(int, const char *, int);
  52 #ifdef _SQUID_MSWIN_
  53 int socket_read_method(int, char *, int);
  54 int socket_write_method(int, const char *, int);
  55 int file_read_method(int, char *, int);
  56 int file_write_method(int, const char *, int);
  57 #else
  58 int msghdr_read_method(int, char *, int);
  59 int msghdr_write_method(int, const char *, int);
  60 #endif
  61
  62 const char *fdTypeStr[] = {
  63     "None",
  64     "Log",
  65     "File",
  66     "Socket",
  67     "Pipe",
  68     "MsgHdr",
  69     "Unknown"
  70 };
  71
  72 static void fdUpdateBiggest(int fd, int);
  73
  74 static void
  75 fdUpdateBiggest(int fd, int opening)
  76 {
  77     if (fd < Biggest_FD)
  78         return;
  79
  80     assert(fd < Squid_MaxFD);
  81
  82     if (fd > Biggest_FD) {
  83         /*
  84          * assert that we are not closing a FD bigger than
  85          * our known biggest FD
  86          */
  87         assert(opening);
  88         Biggest_FD = fd;
  89         return;
  90     }
  91
  92     /* if we are here, then fd == Biggest_FD */
  93     /*
  94      * assert that we are closing the biggest FD; we can't be
  95      * re-opening it
  96      */
  97     assert(!opening);
  98
  99     while (Biggest_FD >= 0 && !fd_table[Biggest_FD].flags.open)
 100         Biggest_FD--;
 101 }
 102
 103 void
 104 fd_close(int fd)
 105 {
 106     fde *F = &fd_table[fd];
 107
 108     if (F->type == FD_FILE) {
 109         assert(F->read_handler == NULL);
 110         assert(F->write_handler == NULL);
 111     }
 112
 113     debugs(51, 3, "fd_close FD " << fd << " " << F->desc);
 114     Comm::SetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
 115     Comm::SetSelect(fd, COMM_SELECT_WRITE, NULL, NULL, 0);
 116     F->flags.open = 0;
 117     fdUpdateBiggest(fd, 0);
 118     Number_FD--;
 119     *F = fde();
 120 }
 121
 122 #ifdef _SQUID_MSWIN_
 123
 124 int
 125 socket_read_method(int fd, char *buf, int len)
 126 {
 127     int i;
 128     PROF_start(recv);
 129     i = recv(fd, (void *) buf, len, 0);
 130     PROF_stop(recv);
 131     return i;
 132 }
 133
 134 int
 135 file_read_method(int fd, char *buf, int len)
 136 {
 137     int i;
 138     PROF_start(read);
 139     i = _read(fd, buf, len);
 140     PROF_stop(read);
 141     return i;
 142 }
 143
 144 int
 145 socket_write_method(int fd, const char *buf, int len)
 146 {
 147     int i;
 148     PROF_start(send);
 149     i = send(fd, (const void *) buf, len, 0);
 150     PROF_stop(send);
 151     return i;
 152 }
 153
 154 int
 155 file_write_method(int fd, const char *buf, int len)
 156 {
 157     int i;
 158     PROF_start(write);
 159     i = (_write(fd, buf, len));
 160     PROF_stop(write);
 161     return i;
 162 }
 163
 164 #else
 165 int
 166 default_read_method(int fd, char *buf, int len)
 167 {
 168     int i;
 169     PROF_start(read);
 170     i = read(fd, buf, len);
 171     PROF_stop(read);
 172     return i;
 173 }
 174
 175 int
 176 default_write_method(int fd, const char *buf, int len)
 177 {
 178     int i;
 179     PROF_start(write);
 180     i = write(fd, buf, len);
 181     PROF_stop(write);
 182     return i;
 183 }
 184
 185 int
 186 msghdr_read_method(int fd, char *buf, int len)
 187 {
 188     PROF_start(read);
 189     const int i = recvmsg(fd, reinterpret_cast<msghdr*>(buf), MSG_DONTWAIT);
 190     PROF_stop(read);
 191     return i;
 192 }
 193
 194 int
 195 msghdr_write_method(int fd, const char *buf, int len)
 196 {
 197     PROF_start(write);
 198     const int i = sendmsg(fd, reinterpret_cast<const msghdr*>(buf), MSG_NOSIGNAL);
 199     PROF_stop(write);
 200     return i > 0 ? len : i; // len is imprecise but the caller expects a match
 201 }
 202
 203 #endif
 204
 205 void
 206 fd_open(int fd, unsigned int type, const char *desc)
 207 {
 208     fde *F;
 209     assert(fd >= 0);
 210     F = &fd_table[fd];
 211
 212     if (F->flags.open) {
 213         debugs(51, 1, "WARNING: Closing open FD " << std::setw(4) << fd);
 214         fd_close(fd);
 215     }
 216
 217     assert(!F->flags.open);
 218     debugs(51, 3, "fd_open() FD " << fd << " " << desc);
 219     F->type = type;
 220     F->flags.open = 1;
 221     F->epoll_state = 0;
 222 #ifdef _SQUID_MSWIN_
 223
 224     F->win32.handle = _get_osfhandle(fd);
 225
 226     switch (type) {
 227
 228     case FD_SOCKET:
 229
 230     case FD_PIPE:
 231         F->read_method = &socket_read_method;
 232         F->write_method = &socket_write_method;
 233         break;
 234
 235     case FD_FILE:
 236
 237     case FD_LOG:
 238         F->read_method = &file_read_method;
 239         F->write_method = &file_write_method;
 240         break;
 241
 242     default:
 243         fatalf("fd_open(): unknown FD type - FD#: %i, type: %u, desc %s\n", fd, type, desc);
 244     }
 245
 246 #else
 247     switch (type) {
 248
 249     case FD_MSGHDR:
 250         F->read_method = &msghdr_read_method;
 251         F->write_method = &msghdr_write_method;
 252         break;
 253
 254     default:
 255         F->read_method = &default_read_method;
 256         F->write_method = &default_write_method;
 257         break;
 258     }
 259
 260 #endif
 261
 262     fdUpdateBiggest(fd, 1);
 263
 264     if (desc)
 265         xstrncpy(F->desc, desc, FD_DESC_SZ);
 266
 267     Number_FD++;
 268 }
 269
 270 void
 271 fd_note(int fd, const char *s)
 272 {
 273     fde *F = &fd_table[fd];
 274     xstrncpy(F->desc, s, FD_DESC_SZ);
 275 }
 276
 277 void
 278 fd_bytes(int fd, int len, unsigned int type)
 279 {
 280     fde *F = &fd_table[fd];
 281
 282     if (len < 0)
 283         return;
 284
 285     assert(type == FD_READ || type == FD_WRITE);
 286
 287     if (type == FD_READ)
 288         F->bytes_read += len;
 289     else
 290         F->bytes_written += len;
 291 }
 292
 293 void
 294 fdDumpOpen(void)
 295 {
 296     int i;
 297     fde *F;
 298
 299     for (i = 0; i < Squid_MaxFD; i++) {
 300         F = &fd_table[i];
 301
 302         if (!F->flags.open)
 303             continue;
 304
 305         if (i == fileno(debug_log))
 306             continue;
 307
 308         debugs(51, 1, "Open FD "<< std::left<< std::setw(10) <<
 309                (F->bytes_read && F->bytes_written ? "READ/WRITE" :
 310                 F->bytes_read ? "READING" : F->bytes_written ? "WRITING" :
 311                 "UNSTARTED")  <<
 312                " "<< std::right << std::setw(4) << i  << " " << F->desc);
 313     }
 314 }
 315
 316 int
 317 fdNFree(void)
 318 {
 319     return Squid_MaxFD - Number_FD - Opening_FD;
 320 }
 321
 322 int
 323 fdUsageHigh(void)
 324 {
 325     int nrfree = fdNFree();
 326
 327     if (nrfree < (RESERVED_FD << 1))
 328         return 1;
 329
 330     if (nrfree < (Number_FD >> 2))
 331         return 1;
 332
 333     return 0;
 334 }
 335
 336 /* Called when we runs out of file descriptors */
 337 void
 338 fdAdjustReserved(void)
 339 {
 340     int newReserve;
 341     int x;
 342     static time_t last = 0;
 343     /*
 344      * don't update too frequently
 345      */
 346
 347     if (last + 5 > squid_curtime)
 348         return;
 349
 350     /*
 351      * Calculate a new reserve, based on current usage and a small extra
 352      */
 353     newReserve = Squid_MaxFD - Number_FD + min(25, Squid_MaxFD / 16);
 354
 355     if (newReserve <= RESERVED_FD)
 356         return;
 357
 358     x = Squid_MaxFD - 20 - min(25, Squid_MaxFD / 16);
 359
 360     if (newReserve > x) {
 361         /* perhaps this should be fatal()? -DW */
 362         debugs(51, 0, "WARNING: This machine has a serious shortage of filedescriptors.");
 363         newReserve = x;
 364     }
 365
 366     if (Squid_MaxFD - newReserve < min(256, Squid_MaxFD / 2))
 367         fatalf("Too few filedescriptors available in the system (%d usable of %d).\n", Squid_MaxFD - newReserve, Squid_MaxFD);
 368
 369     debugs(51, 0, "Reserved FD adjusted from " << RESERVED_FD << " to " << newReserve << " due to failures");
 370     RESERVED_FD = newReserve;
 371 }