src/log/ModDaemon.cc

   1 /*
   2  * DEBUG: section 50    Log file handling
   3  * AUTHOR: Adrian Chadd <adrian@squid-cache.org>
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  */
  32
  33 #include "squid.h"
  34 #include "cbdata.h"
  35 #include "comm/Loops.h"
  36 #include "fde.h"
  37 #include "globals.h"
  38 #include "log/Config.h"
  39 #include "log/File.h"
  40 #include "log/ModDaemon.h"
  41 #include "SquidConfig.h"
  42 #include "SquidIpc.h"
  43 #include "SquidTime.h"
  44
  45 #include <cerrno>
  46
  47 /* How many buffers to keep before we say we've buffered too much */
  48 #define LOGFILE_MAXBUFS         128
  49
  50 /* Size of the logfile buffer */
  51 /*
  52  * For optimal performance this should match LOGFILE_BUFSIZ in logfile-daemon.c
  53  */
  54 #define LOGFILE_BUFSZ           32768
  55
  56 /* How many seconds between warnings */
  57 #define LOGFILE_WARN_TIME       30
  58
  59 static LOGWRITE logfile_mod_daemon_writeline;
  60 static LOGLINESTART logfile_mod_daemon_linestart;
  61 static LOGLINEEND logfile_mod_daemon_lineend;
  62 static LOGROTATE logfile_mod_daemon_rotate;
  63 static LOGFLUSH logfile_mod_daemon_flush;
  64 static LOGCLOSE logfile_mod_daemon_close;
  65
  66 static void logfile_mod_daemon_append(Logfile * lf, const char *buf, int len);
  67
  68 struct _l_daemon {
  69     int rfd, wfd;
  70     char eol;
  71     pid_t pid;
  72     int flush_pending;
  73     dlink_list bufs;
  74     int nbufs;
  75     int last_warned;
  76 };
  77
  78 typedef struct _l_daemon l_daemon_t;
  79
  80 /* Internal code */
  81 static void
  82 logfileNewBuffer(Logfile * lf)
  83 {
  84     l_daemon_t *ll = (l_daemon_t *) lf->data;
  85     logfile_buffer_t *b;
  86
  87     debugs(50, 5, "logfileNewBuffer: " << lf->path << ": new buffer");
  88
  89     b = static_cast<logfile_buffer_t*>(xcalloc(1, sizeof(logfile_buffer_t)));
  90     assert(b != NULL);
  91     b->buf = static_cast<char*>(xcalloc(1, LOGFILE_BUFSZ));
  92     assert(b->buf != NULL);
  93     b->size = LOGFILE_BUFSZ;
  94     b->written_len = 0;
  95     b->len = 0;
  96     dlinkAddTail(b, &b->node, &ll->bufs);
  97     ++ ll->nbufs;
  98 }
  99
 100 static void
 101 logfileFreeBuffer(Logfile * lf, logfile_buffer_t * b)
 102 {
 103     l_daemon_t *ll = (l_daemon_t *) lf->data;
 104     assert(b != NULL);
 105     dlinkDelete(&b->node, &ll->bufs);
 106     -- ll->nbufs;
 107     xfree(b->buf);
 108     xfree(b);
 109 }
 110
 111 static void
 112 logfileHandleWrite(int fd, void *data)
 113 {
 114     Logfile *lf = static_cast<Logfile *>(data);
 115     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 116
 117     /*
 118      * We'll try writing the first entry until its done - if we
 119      * get a partial write then we'll re-schedule until its completed.
 120      * Its naive but it'll do for now.
 121      */
 122     if (!ll->bufs.head) // abort if there is nothing pending right now.
 123         return;
 124
 125     logfile_buffer_t *b = static_cast<logfile_buffer_t*>(ll->bufs.head->data);
 126     assert(b != NULL);
 127     ll->flush_pending = 0;
 128
 129     int ret = FD_WRITE_METHOD(ll->wfd, b->buf + b->written_len, b->len - b->written_len);
 130     debugs(50, 3, lf->path << ": write returned " << ret);
 131     if (ret < 0) {
 132         if (ignoreErrno(errno)) {
 133             /* something temporary */
 134             Comm::SetSelect(ll->wfd, COMM_SELECT_WRITE, logfileHandleWrite, lf, 0);
 135             ll->flush_pending = 1;
 136             return;
 137         }
 138         debugs(50, DBG_IMPORTANT,"logfileHandleWrite: " << lf->path << ": error writing (" << xstrerror() << ")");
 139         /* XXX should handle this better */
 140         fatal("I don't handle this error well!");
 141     }
 142     if (ret == 0) {
 143         /* error? */
 144         debugs(50, DBG_IMPORTANT, "logfileHandleWrite: " << lf->path << ": wrote 0 bytes?");
 145         /* XXX should handle this better */
 146         fatal("I don't handle this error well!");
 147     }
 148     /* ret > 0, so something was written */
 149     b->written_len += ret;
 150     assert(b->written_len <= b->len);
 151     if (b->written_len == b->len) {
 152         /* written the whole buffer! */
 153         logfileFreeBuffer(lf, b);
 154         b = NULL;
 155     }
 156     /* Is there more to write? */
 157     if (!ll->bufs.head)
 158         return;
 159     /* there is, so schedule more */
 160
 161     Comm::SetSelect(ll->wfd, COMM_SELECT_WRITE, logfileHandleWrite, lf, 0);
 162     ll->flush_pending = 1;
 163     return;
 164 }
 165
 166 static void
 167 logfileQueueWrite(Logfile * lf)
 168 {
 169     l_daemon_t *ll = (l_daemon_t *) lf->data;
 170     if (ll->flush_pending || ll->bufs.head == NULL) {
 171         return;
 172     }
 173     ll->flush_pending = 1;
 174     if (ll->bufs.head) {
 175         logfile_buffer_t *b = static_cast<logfile_buffer_t*>(ll->bufs.head->data);
 176         if (b->len + 2 <= b->size)
 177             logfile_mod_daemon_append(lf, "F\n", 2);
 178     }
 179     /* Ok, schedule a write-event */
 180     Comm::SetSelect(ll->wfd, COMM_SELECT_WRITE, logfileHandleWrite, lf, 0);
 181 }
 182
 183 static void
 184 logfile_mod_daemon_append(Logfile * lf, const char *buf, int len)
 185 {
 186     l_daemon_t *ll = (l_daemon_t *) lf->data;
 187     logfile_buffer_t *b;
 188     int s;
 189
 190     /* Is there a buffer? If not, create one */
 191     if (ll->bufs.head == NULL) {
 192         logfileNewBuffer(lf);
 193     }
 194     debugs(50, 3, "logfile_mod_daemon_append: " << lf->path << ": appending " << len << " bytes");
 195     /* Copy what can be copied */
 196     while (len > 0) {
 197         b = static_cast<logfile_buffer_t*>(ll->bufs.tail->data);
 198         debugs(50, 3, "logfile_mod_daemon_append: current buffer has " << b->len << " of " << b->size << " bytes before append");
 199         s = min(len, (b->size - b->len));
 200         memcpy(b->buf + b->len, buf, s);
 201         len = len - s;
 202         buf = buf + s;
 203         b->len = b->len + s;
 204         assert(b->len <= LOGFILE_BUFSZ);
 205         assert(len >= 0);
 206         if (len > 0) {
 207             logfileNewBuffer(lf);
 208         }
 209     }
 210 }
 211
 212 /*
 213  * only schedule a flush (write) if one isn't scheduled.
 214  */
 215 static void
 216 logfileFlushEvent(void *data)
 217 {
 218     Logfile *lf = static_cast<Logfile *>(data);
 219
 220     /*
 221      * This might work better if we keep track of when we wrote last and only
 222      * schedule a write if we haven't done so in the last second or two.
 223      */
 224     logfileQueueWrite(lf);
 225     eventAdd("logfileFlush", logfileFlushEvent, lf, 1.0, 1);
 226 }
 227
 228 /* External code */
 229
 230 int
 231 logfile_mod_daemon_open(Logfile * lf, const char *path, size_t bufsz, int fatal_flag)
 232 {
 233     const char *args[5];
 234     char *tmpbuf;
 235     l_daemon_t *ll;
 236
 237     lf->f_close = logfile_mod_daemon_close;
 238     lf->f_linewrite = logfile_mod_daemon_writeline;
 239     lf->f_linestart = logfile_mod_daemon_linestart;
 240     lf->f_lineend = logfile_mod_daemon_lineend;
 241     lf->f_flush = logfile_mod_daemon_flush;
 242     lf->f_rotate = logfile_mod_daemon_rotate;
 243
 244     cbdataInternalLock(lf); // WTF?
 245     debugs(50, DBG_IMPORTANT, "Logfile Daemon: opening log " << path);
 246     ll = static_cast<l_daemon_t*>(xcalloc(1, sizeof(*ll)));
 247     lf->data = ll;
 248     ll->eol = 1;
 249     {
 250         Ip::Address localhost;
 251         args[0] = "(logfile-daemon)";
 252         args[1] = path;
 253         args[2] = NULL;
 254         localhost.setLocalhost();
 255         ll->pid = ipcCreate(IPC_STREAM, Log::TheConfig.logfile_daemon, args, "logfile-daemon", localhost, &ll->rfd, &ll->wfd, NULL);
 256         if (ll->pid < 0)
 257             fatal("Couldn't start logfile helper");
 258     }
 259     ll->nbufs = 0;
 260
 261     /* Queue the initial control data */
 262     tmpbuf = static_cast<char*>(xmalloc(BUFSIZ));
 263     snprintf(tmpbuf, BUFSIZ, "r%d\nb%d\n", Config.Log.rotateNumber, Config.onoff.buffered_logs);
 264     logfile_mod_daemon_append(lf, tmpbuf, strlen(tmpbuf));
 265     xfree(tmpbuf);
 266
 267     /* Start the flush event */
 268     eventAdd("logfileFlush", logfileFlushEvent, lf, 1.0, 1);
 269
 270     return 1;
 271 }
 272
 273 static void
 274 logfile_mod_daemon_close(Logfile * lf)
 275 {
 276     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 277     debugs(50, DBG_IMPORTANT, "Logfile Daemon: closing log " << lf->path);
 278     logfileFlush(lf);
 279     if (ll->rfd == ll->wfd)
 280         comm_close(ll->rfd);
 281     else {
 282         comm_close(ll->rfd);
 283         comm_close(ll->wfd);
 284     }
 285     kill(ll->pid, SIGTERM);
 286     eventDelete(logfileFlushEvent, lf);
 287     xfree(ll);
 288     lf->data = NULL;
 289     cbdataInternalUnlock(lf); // WTF??
 290 }
 291
 292 static void
 293 logfile_mod_daemon_rotate(Logfile * lf)
 294 {
 295     char tb[3];
 296     debugs(50, DBG_IMPORTANT, "logfileRotate: " << lf->path);
 297     tb[0] = 'R';
 298     tb[1] = '\n';
 299     tb[2] = '\0';
 300     logfile_mod_daemon_append(lf, tb, 2);
 301 }
 302
 303 /*
 304  * This routine assumes that up to one line is written. Don't try to
 305  * call this routine with more than one line or subsequent lines
 306  * won't be prefixed with the command type and confuse the logging
 307  * daemon somewhat.
 308  */
 309 static void
 310 logfile_mod_daemon_writeline(Logfile * lf, const char *buf, size_t len)
 311 {
 312     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 313     /* Make sure the logfile buffer isn't too large */
 314     if (ll->nbufs > LOGFILE_MAXBUFS) {
 315         if (ll->last_warned < squid_curtime - LOGFILE_WARN_TIME) {
 316             ll->last_warned = squid_curtime;
 317             debugs(50, DBG_IMPORTANT, "Logfile: " << lf->path << ": queue is too large; some log messages have been lost.");
 318         }
 319         return;
 320     }
 321     /* Append this data to the end buffer; create a new one if needed */
 322     /* Are we eol? If so, prefix with our logfile command byte */
 323     logfile_mod_daemon_append(lf, buf, len);
 324 }
 325
 326 static void
 327 logfile_mod_daemon_linestart(Logfile * lf)
 328 {
 329     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 330     char tb[2];
 331     assert(ll->eol == 1);
 332     ll->eol = 0;
 333     tb[0] = 'L';
 334     tb[1] = '\0';
 335     logfile_mod_daemon_append(lf, tb, 1);
 336 }
 337
 338 static void
 339 logfile_mod_daemon_lineend(Logfile * lf)
 340 {
 341     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 342     logfile_buffer_t *b;
 343     assert(ll->eol == 0);
 344     ll->eol = 1;
 345     /* Kick a write off if the head buffer is -full- */
 346     if (ll->bufs.head != NULL) {
 347         b = static_cast<logfile_buffer_t*>(ll->bufs.head->data);
 348         if (b->node.next != NULL || !Config.onoff.buffered_logs)
 349             logfileQueueWrite(lf);
 350     }
 351 }
 352
 353 static void
 354 logfile_mod_daemon_flush(Logfile * lf)
 355 {
 356     l_daemon_t *ll = static_cast<l_daemon_t *>(lf->data);
 357     if (commUnsetNonBlocking(ll->wfd)) {
 358         debugs(50, DBG_IMPORTANT, "Logfile Daemon: Couldn't set the pipe blocking for flush! You're now missing some log entries.");
 359         return;
 360     }
 361     while (ll->bufs.head != NULL) {
 362         logfileHandleWrite(ll->wfd, lf);
 363     }
 364     if (commSetNonBlocking(ll->wfd)) {
 365         fatalf("Logfile Daemon: %s: Couldn't set the pipe non-blocking for flush!\n", lf->path);
 366         return;
 367     }
 368 }