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