src/fd.cc

   1
   2 /*
   3  * $Id: fd.cc,v 1.59 2007/09/25 13:24:59 hno Exp $
   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 "fde.h"
  38 #include "SquidTime.h"
  39
  40 int default_read_method(int, char *, int);
  41 int default_write_method(int, const char *, int);
  42 #ifdef _SQUID_MSWIN_
  43 int socket_read_method(int, char *, int);
  44 int socket_write_method(int, const char *, int);
  45 int file_read_method(int, char *, int);
  46 int file_write_method(int, const char *, int);
  47 #endif
  48
  49 const char *fdTypeStr[] =
  50     {
  51         "None",
  52         "Log",
  53         "File",
  54         "Socket",
  55         "Pipe",
  56         "Unknown"
  57     };
  58
  59 static void fdUpdateBiggest(int fd, int);
  60
  61 static void
  62 fdUpdateBiggest(int fd, int opening)
  63 {
  64     if (fd < Biggest_FD)
  65         return;
  66
  67     assert(fd < Squid_MaxFD);
  68
  69     if (fd > Biggest_FD) {
  70         /*
  71          * assert that we are not closing a FD bigger than
  72          * our known biggest FD
  73          */
  74         assert(opening);
  75         Biggest_FD = fd;
  76         return;
  77     }
  78
  79     /* if we are here, then fd == Biggest_FD */
  80     /*
  81      * assert that we are closing the biggest FD; we can't be
  82      * re-opening it
  83      */
  84     assert(!opening);
  85
  86     while (Biggest_FD >= 0 && !fd_table[Biggest_FD].flags.open)
  87         Biggest_FD--;
  88 }
  89
  90 void
  91 fd_close(int fd)
  92 {
  93     fde *F = &fd_table[fd];
  94
  95     if (F->type == FD_FILE) {
  96         assert(F->read_handler == NULL);
  97         assert(F->write_handler == NULL);
  98     }
  99
 100     debugs(51, 3, "fd_close FD " << fd << " " << F->desc);
 101     commSetSelect(fd, COMM_SELECT_READ, NULL, NULL, 0);
 102     commSetSelect(fd, COMM_SELECT_WRITE, NULL, NULL, 0);
 103     F->flags.open = 0;
 104     fdUpdateBiggest(fd, 0);
 105     Number_FD--;
 106     memset(F, '\0', sizeof(fde));
 107     F->timeout = 0;
 108 }
 109
 110 #ifdef _SQUID_MSWIN_
 111
 112 int
 113 socket_read_method(int fd, char *buf, int len)
 114 {
 115     int i;
 116     PROF_start(send);
 117     i = recv(fd, (void *) buf, len, 0);
 118     PROF_stop(send);
 119     return i;
 120 }
 121
 122 int
 123 file_read_method(int fd, char *buf, int len)
 124 {
 125     int i;
 126     PROF_start(read);
 127     i = _read(fd, buf, len);
 128     PROF_stop(read);
 129     return i;
 130 }
 131
 132 int
 133 socket_write_method(int fd, const char *buf, int len)
 134 {
 135     int i;
 136     PROF_start(send);
 137     i = send(fd, (const void *) buf, len, 0);
 138     PROF_stop(send);
 139     return i;
 140 }
 141
 142 int
 143 file_write_method(int fd, const char *buf, int len)
 144 {
 145     return (_write(fd, buf, len));
 146 }
 147
 148 #else
 149 int
 150 default_read_method(int fd, char *buf, int len)
 151 {
 152     int i;
 153     PROF_start(read);
 154     i = read(fd, buf, len);
 155     PROF_stop(read);
 156     return i;
 157 }
 158
 159 int
 160 default_write_method(int fd, const char *buf, int len)
 161 {
 162     int i;
 163     PROF_start(write);
 164     i = write(fd, buf, len);
 165     PROF_stop(write);
 166     return i;
 167 }
 168
 169 #endif
 170
 171 void
 172 fd_open(int fd, unsigned int type, const char *desc)
 173 {
 174     fde *F;
 175     assert(fd >= 0);
 176     F = &fd_table[fd];
 177
 178     if (F->flags.open) {
 179         debugs(51, 1, "WARNING: Closing open FD " << std::setw(4) << fd);
 180         fd_close(fd);
 181     }
 182
 183     assert(!F->flags.open);
 184     debugs(51, 3, "fd_open FD " << fd << " " << desc);
 185     F->type = type;
 186     F->flags.open = 1;
 187     F->epoll_state = 0;
 188 #ifdef _SQUID_MSWIN_
 189
 190     F->win32.handle = _get_osfhandle(fd);
 191
 192     switch (type) {
 193
 194     case FD_SOCKET:
 195
 196     case FD_PIPE:
 197         F->read_method = &socket_read_method;
 198         F->write_method = &socket_write_method;
 199         break;
 200
 201     case FD_FILE:
 202
 203     case FD_LOG:
 204         F->read_method = &file_read_method;
 205         F->write_method = &file_write_method;
 206         break;
 207
 208     default:
 209         fatalf("fd_open(): unknown FD type - FD#: %i, type: %u, desc %s\n", fd, type, desc);
 210     }
 211
 212 #else
 213     F->read_method = &default_read_method;
 214
 215     F->write_method = &default_write_method;
 216
 217 #endif
 218
 219     fdUpdateBiggest(fd, 1);
 220
 221     if (desc)
 222         xstrncpy(F->desc, desc, FD_DESC_SZ);
 223
 224     Number_FD++;
 225 }
 226
 227 void
 228 fd_note(int fd, const char *s)
 229 {
 230     fde *F = &fd_table[fd];
 231     xstrncpy(F->desc, s, FD_DESC_SZ);
 232 }
 233
 234 void
 235 fd_bytes(int fd, int len, unsigned int type)
 236 {
 237     fde *F = &fd_table[fd];
 238
 239     if (len < 0)
 240         return;
 241
 242     assert(type == FD_READ || type == FD_WRITE);
 243
 244     if (type == FD_READ)
 245         F->bytes_read += len;
 246     else
 247         F->bytes_written += len;
 248 }
 249
 250 void
 251 fdDumpOpen(void)
 252 {
 253     int i;
 254     fde *F;
 255
 256     for (i = 0; i < Squid_MaxFD; i++) {
 257         F = &fd_table[i];
 258
 259         if (!F->flags.open)
 260             continue;
 261
 262         if (i == fileno(debug_log))
 263             continue;
 264
 265         debugs(51, 1, "Open FD "<< std::left<< std::setw(10) <<
 266                (F->bytes_read && F->bytes_written ? "READ/WRITE" :
 267                 F->bytes_read ? "READING" : F->bytes_written ? "WRITING" :
 268                 null_string)  <<
 269                " "<< std::right << std::setw(4) << i  << " " << F->desc);
 270     }
 271 }
 272
 273 int
 274 fdNFree(void)
 275 {
 276     return Squid_MaxFD - Number_FD - Opening_FD;
 277 }
 278
 279 int
 280 fdUsageHigh(void)
 281 {
 282     int nrfree = fdNFree();
 283
 284     if (nrfree < (RESERVED_FD << 1))
 285         return 1;
 286
 287     if (nrfree < (Number_FD >> 2))
 288         return 1;
 289
 290     return 0;
 291 }
 292
 293 /* Called when we runs out of file descriptors */
 294 void
 295 fdAdjustReserved(void)
 296 {
 297     int newReserve;
 298     int x;
 299     static time_t last = 0;
 300     /*
 301      * don't update too frequently
 302      */
 303
 304     if (last + 5 > squid_curtime)
 305         return;
 306
 307     /*
 308      * Calculate a new reserve, based on current usage and a small extra
 309      */
 310     newReserve = Squid_MaxFD - Number_FD + XMIN(25, Squid_MaxFD / 16);
 311
 312     if (newReserve <= RESERVED_FD)
 313         return;
 314
 315     x = Squid_MaxFD - 20 - XMIN(25, Squid_MaxFD / 16);
 316
 317     if (newReserve > x) {
 318         /* perhaps this should be fatal()? -DW */
 319         debugs(51, 0, "WARNING: This machine has a serious shortage of filedescriptors.");
 320         newReserve = x;
 321     }
 322
 323     if (Squid_MaxFD - newReserve < XMIN(256, Squid_MaxFD / 2))
 324         fatalf("Too few filedescriptors available in the system (%d usable of %d).\n", Squid_MaxFD - newReserve, Squid_MaxFD);
 325
 326     debugs(51, 0, "Reserved FD adjusted from " << RESERVED_FD << " to " << newReserve << " due to failures");
 327     RESERVED_FD = newReserve;
 328 }