src/DiskIO/DiskDaemon/diskd.cc

   1 /*
   2  * $Id$
   3  *
   4  * DEBUG: section --    External DISKD process implementation.
   5  * AUTHOR: Harvest Derived
   6  *
   7  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   8  * ----------------------------------------------------------
   9  *
  10  *  Squid is the result of efforts by numerous individuals from
  11  *  the Internet community; see the CONTRIBUTORS file for full
  12  *  details.   Many organizations have provided support for Squid's
  13  *  development; see the SPONSORS file for full details.  Squid is
  14  *  Copyrighted (C) 2001 by the Regents of the University of
  15  *  California; see the COPYRIGHT file for full details.  Squid
  16  *  incorporates software developed and/or copyrighted by other
  17  *  sources; see the CREDITS file for full details.
  18  *
  19  *  This program is free software; you can redistribute it and/or modify
  20  *  it under the terms of the GNU General Public License as published by
  21  *  the Free Software Foundation; either version 2 of the License, or
  22  *  (at your option) any later version.
  23  *
  24  *  This program is distributed in the hope that it will be useful,
  25  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  26  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  27  *  GNU General Public License for more details.
  28  *
  29  *  You should have received a copy of the GNU General Public License
  30  *  along with this program; if not, write to the Free Software
  31  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  32  *
  33  */
  34
  35 #include "config.h"
  36 #include "DiskIO/DiskDaemon/diomsg.h"
  37 #include "hash.h"
  38
  39 #if HAVE_ERRNO_H
  40 #include <errno.h>
  41 #endif
  42 #include <sys/ipc.h>
  43 #include <sys/msg.h>
  44 #include <sys/shm.h>
  45 #if HAVE_IOSTREAM
  46 #include <iostream>
  47 #endif
  48
  49 void
  50 xassert(const char *msg, const char *file, int line)
  51 {
  52     fprintf(stderr,"assertion failed: %s:%d: \"%s\"\n", file, line, msg);
  53
  54     abort();
  55 }
  56
  57 const int diomsg::msg_snd_rcv_sz = sizeof(diomsg) - sizeof(mtyp_t);
  58 #define DEBUG(LEVEL) if ((LEVEL) <= DebugLevel)
  59
  60 typedef struct _file_state file_state;
  61
  62 struct _file_state {
  63     void *key;
  64     file_state *next;
  65     int id;
  66     int fd;
  67     off_t offset;
  68 };
  69
  70 static hash_table *hash = NULL;
  71 static pid_t mypid;
  72 static char *shmbuf;
  73 static int DebugLevel = 0;
  74
  75 static int
  76 do_open(diomsg * r, int len, const char *buf)
  77 {
  78     int fd;
  79     file_state *fs;
  80     /*
  81      * note r->offset holds open() flags
  82      */
  83     fd = open(buf, r->offset, 0600);
  84
  85     if (fd < 0) {
  86         DEBUG(1) {
  87             fprintf(stderr, "%d %s: ", (int) mypid, buf);
  88             perror("open");
  89         }
  90
  91         return -errno;
  92     }
  93
  94     fs = (file_state *)xcalloc(1, sizeof(*fs));
  95     fs->id = r->id;
  96     fs->key = &fs->id;          /* gack */
  97     fs->fd = fd;
  98     hash_join(hash, (hash_link *) fs);
  99     DEBUG(2) {
 100         fprintf(stderr, "%d OPEN  id %d, FD %d, fs %p\n",
 101                 (int) mypid,
 102                 fs->id,
 103                 fs->fd,
 104                 fs);
 105     }
 106     return fd;
 107 }
 108
 109 static int
 110 do_close(diomsg * r, int len)
 111 {
 112     int fd;
 113     file_state *fs;
 114     fs = (file_state *) hash_lookup(hash, &r->id);
 115
 116     if (NULL == fs) {
 117         errno = EBADF;
 118         DEBUG(1) {
 119             fprintf(stderr, "%d CLOSE id %d: ", (int) mypid, r->id);
 120             perror("do_close");
 121         }
 122
 123         return -errno;
 124     }
 125
 126     fd = fs->fd;
 127     hash_remove_link(hash, (hash_link *) fs);
 128     DEBUG(2) {
 129         fprintf(stderr, "%d CLOSE id %d, FD %d, fs %p\n",
 130                 (int) mypid,
 131                 r->id,
 132                 fs->fd,
 133                 fs);
 134     }
 135     xfree(fs);
 136     return close(fd);
 137 }
 138
 139 static int
 140 do_read(diomsg * r, int len, char *buf)
 141 {
 142     int x;
 143     int readlen = r->size;
 144     file_state *fs;
 145     fs = (file_state *) hash_lookup(hash, &r->id);
 146
 147     if (NULL == fs) {
 148         errno = EBADF;
 149         DEBUG(1) {
 150             fprintf(stderr, "%d READ  id %d: ", (int) mypid, r->id);
 151             perror("do_read");
 152         }
 153
 154         return -errno;
 155     }
 156
 157     if (r->offset > -1 && r->offset != fs->offset) {
 158         DEBUG(2) {
 159             fprintf(stderr, "seeking to %"PRId64"\n", (int64_t)r->offset);
 160         }
 161
 162         if (lseek(fs->fd, r->offset, SEEK_SET) < 0) {
 163             DEBUG(1) {
 164                 fprintf(stderr, "%d FD %d, offset %"PRId64": ", (int) mypid, fs->fd, (int64_t)r->offset);
 165                 perror("lseek");
 166             }
 167         }
 168     }
 169
 170     x = read(fs->fd, buf, readlen);
 171     DEBUG(2) {
 172         fprintf(stderr, "%d READ %d,%d,%"PRId64" ret %d\n", (int) mypid,
 173                 fs->fd, readlen, (int64_t)r->offset, x);
 174     }
 175
 176     if (x < 0) {
 177         DEBUG(1) {
 178             fprintf(stderr, "%d FD %d: ", (int) mypid, fs->fd);
 179             perror("read");
 180         }
 181
 182         return -errno;
 183     }
 184
 185     fs->offset = r->offset + x;
 186     return x;
 187 }
 188
 189 static int
 190 do_write(diomsg * r, int len, const char *buf)
 191 {
 192     int wrtlen = r->size;
 193     int x;
 194     file_state *fs;
 195     fs = (file_state *) hash_lookup(hash, &r->id);
 196
 197     if (NULL == fs) {
 198         errno = EBADF;
 199         DEBUG(1) {
 200             fprintf(stderr, "%d WRITE id %d: ", (int) mypid, r->id);
 201             perror("do_write");
 202         }
 203
 204         return -errno;
 205     }
 206
 207     if (r->offset > -1 && r->offset != fs->offset) {
 208         if (lseek(fs->fd, r->offset, SEEK_SET) < 0) {
 209             DEBUG(1) {
 210                 fprintf(stderr, "%d FD %d, offset %"PRId64": ", (int) mypid, fs->fd, (int64_t)r->offset);
 211                 perror("lseek");
 212             }
 213         }
 214     }
 215
 216     DEBUG(2) {
 217         fprintf(stderr, "%d WRITE %d,%d,%"PRId64"\n", (int) mypid,
 218                 fs->fd, wrtlen, (int64_t)r->offset);
 219     }
 220     x = write(fs->fd, buf, wrtlen);
 221
 222     if (x < 0) {
 223         DEBUG(1) {
 224             fprintf(stderr, "%d FD %d: ", (int) mypid, fs->fd);
 225             perror("write");
 226         }
 227
 228         return -errno;
 229     }
 230
 231     fs->offset = r->offset + x;
 232     return x;
 233 }
 234
 235 static int
 236 do_unlink(diomsg * r, int len, const char *buf)
 237 {
 238     if (unlink(buf) < 0) {
 239         DEBUG(1) {
 240             fprintf(stderr, "%d UNLNK id %d %s: ", (int) mypid, r->id, buf);
 241             perror("unlink");
 242         }
 243
 244         return -errno;
 245     }
 246
 247     DEBUG(2) {
 248         fprintf(stderr, "%d UNLNK %s\n", (int) mypid, buf);
 249     }
 250     return 0;
 251 }
 252
 253 static void
 254 msg_handle(diomsg * r, int rl, diomsg * s)
 255 {
 256     char *buf = NULL;
 257     s->mtype = r->mtype;
 258     s->id = r->id;
 259     s->seq_no = r->seq_no;      /* optional, debugging */
 260     s->callback_data = r->callback_data;
 261     s->requestor = r->requestor;
 262     s->size = 0;                /* optional, debugging */
 263     s->offset = 0;              /* optional, debugging */
 264     s->shm_offset = r->shm_offset;
 265     s->newstyle = r->newstyle;
 266
 267     if (s->shm_offset > -1)
 268         buf = shmbuf + s->shm_offset;
 269
 270     switch (r->mtype) {
 271
 272     case _MQD_OPEN:
 273
 274     case _MQD_CREATE:
 275         s->status = do_open(r, rl, buf);
 276         break;
 277
 278     case _MQD_CLOSE:
 279         s->status = do_close(r, rl);
 280         break;
 281
 282     case _MQD_READ:
 283         s->status = do_read(r, rl, buf);
 284         break;
 285
 286     case _MQD_WRITE:
 287         s->status = do_write(r, rl, buf);
 288         break;
 289
 290     case _MQD_UNLINK:
 291         s->status = do_unlink(r, rl, buf);
 292         break;
 293
 294     default:
 295         assert(0);
 296         break;
 297     }
 298 }
 299
 300 static int
 301 fsCmp(const void *a, const void *b)
 302 {
 303     const int *A = (const int *)a;
 304     const int *B = (const int *)b;
 305     return *A != *B;
 306 }
 307
 308 static unsigned int
 309 fsHash(const void *key, unsigned int n)
 310 {
 311     /* note, n must be a power of 2! */
 312     const int *k = (const int *)key;
 313     return (*k & (--n));
 314 }
 315
 316 SQUIDCEXTERN {
 317     static void
 318     alarm_handler(int sig) {
 319         (void) 0;
 320     }
 321 };
 322
 323 int
 324 main(int argc, char *argv[])
 325 {
 326     int key;
 327     int rmsgid;
 328     int smsgid;
 329     int shmid;
 330     diomsg rmsg;
 331     diomsg smsg;
 332     int rlen;
 333     char rbuf[512];
 334
 335     struct sigaction sa;
 336     setbuf(stdout, NULL);
 337     setbuf(stderr, NULL);
 338     mypid = getpid();
 339     assert(4 == argc);
 340     key = atoi(argv[1]);
 341     rmsgid = msgget(key, 0600);
 342
 343     if (rmsgid < 0) {
 344         perror("msgget");
 345         return 1;
 346     }
 347
 348     key = atoi(argv[2]);
 349     smsgid = msgget(key, 0600);
 350
 351     if (smsgid < 0) {
 352         perror("msgget");
 353         return 1;
 354     }
 355
 356     key = atoi(argv[3]);
 357     shmid = shmget(key, 0, 0600);
 358
 359     if (shmid < 0) {
 360         perror("shmget");
 361         return 1;
 362     }
 363
 364     shmbuf = (char *)shmat(shmid, NULL, 0);
 365
 366     if (shmbuf == (void *) -1) {
 367         perror("shmat");
 368         return 1;
 369     }
 370
 371     hash = hash_create(fsCmp, 1 << 4, fsHash);
 372     assert(hash);
 373     fcntl(0, F_SETFL, SQUID_NONBLOCK);
 374     memset(&sa, '\0', sizeof(sa));
 375     sa.sa_handler = alarm_handler;
 376     sa.sa_flags = SA_RESTART;
 377     sigaction(SIGALRM, &sa, NULL);
 378
 379     for (;;) {
 380         alarm(1);
 381         memset(&rmsg, '\0', sizeof(rmsg));
 382         DEBUG(2) {
 383             std::cerr << "msgrcv: " << rmsgid << ", "
 384                       << &rmsg << ", " << diomsg::msg_snd_rcv_sz
 385                       << ", " << 0 << ", " << 0 << std::endl;
 386         }
 387         rlen = msgrcv(rmsgid, &rmsg, diomsg::msg_snd_rcv_sz, 0, 0);
 388
 389         if (rlen < 0) {
 390             if (EINTR == errno) {
 391                 if (read(0, rbuf, 512) <= 0) {
 392                     if (EWOULDBLOCK == errno)
 393                         (void) 0;
 394                     else if (EAGAIN == errno)
 395                         (void) 0;
 396                     else
 397                         break;
 398                 }
 399             }
 400
 401             if (EAGAIN == errno) {
 402                 continue;
 403             }
 404
 405             perror("msgrcv");
 406             break;
 407         }
 408
 409         alarm(0);
 410         msg_handle(&rmsg, rlen, &smsg);
 411
 412         if (msgsnd(smsgid, &smsg, diomsg::msg_snd_rcv_sz, 0) < 0) {
 413             perror("msgsnd");
 414             break;
 415         }
 416     }
 417
 418     DEBUG(2) {
 419         fprintf(stderr, "%d diskd exiting\n", (int) mypid);
 420     }
 421
 422     if (msgctl(rmsgid, IPC_RMID, 0) < 0)
 423         perror("msgctl IPC_RMID");
 424
 425     if (msgctl(smsgid, IPC_RMID, 0) < 0)
 426         perror("msgctl IPC_RMID");
 427
 428     if (shmdt(shmbuf) < 0)
 429         perror("shmdt");
 430
 431     if (shmctl(shmid, IPC_RMID, 0) < 0)
 432         perror("shmctl IPC_RMID");
 433
 434     return 0;
 435 }