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 "squid.h"
  37
  38 #include <sys/ipc.h>
  39 #include <sys/msg.h>
  40 #include <sys/shm.h>
  41
  42 #include "DiskIO/DiskDaemon/diomsg.h"
  43
  44 void
  45 xassert(const char *msg, const char *file, int line)
  46 {
  47     fprintf(stderr,"assertion failed: %s:%d: \"%s\"\n", file, line, msg);
  48
  49     abort();
  50 }
  51
  52 const int diomsg::msg_snd_rcv_sz = sizeof(diomsg) - sizeof(mtyp_t);
  53 #define DEBUG(LEVEL) if ((LEVEL) <= DebugLevel)
  54
  55 typedef struct _file_state file_state;
  56
  57 struct _file_state {
  58     void *key;
  59     file_state *next;
  60     int id;
  61     int fd;
  62     off_t offset;
  63 };
  64
  65 static hash_table *hash = NULL;
  66 static pid_t mypid;
  67 static char *shmbuf;
  68 static int DebugLevel = 0;
  69
  70 static int
  71 do_open(diomsg * r, int len, const char *buf)
  72 {
  73     int fd;
  74     file_state *fs;
  75     /*
  76      * note r->offset holds open() flags
  77      */
  78     fd = open(buf, r->offset, 0600);
  79
  80     if (fd < 0) {
  81         DEBUG(1) {
  82             fprintf(stderr, "%d %s: ", (int) mypid, buf);
  83             perror("open");
  84         }
  85
  86         return -errno;
  87     }
  88
  89     fs = (file_state *)xcalloc(1, sizeof(*fs));
  90     fs->id = r->id;
  91     fs->key = &fs->id;          /* gack */
  92     fs->fd = fd;
  93     hash_join(hash, (hash_link *) fs);
  94     DEBUG(2)
  95     fprintf(stderr, "%d OPEN  id %d, FD %d, fs %p\n",
  96             (int) mypid,
  97             fs->id,
  98             fs->fd,
  99             fs);
 100     return fd;
 101 }
 102
 103 static int
 104 do_close(diomsg * r, int len)
 105 {
 106     int fd;
 107     file_state *fs;
 108     fs = (file_state *) hash_lookup(hash, &r->id);
 109
 110     if (NULL == fs) {
 111         errno = EBADF;
 112         DEBUG(1) {
 113             fprintf(stderr, "%d CLOSE id %d: ", (int) mypid, r->id);
 114             perror("do_close");
 115         }
 116
 117         return -errno;
 118     }
 119
 120     fd = fs->fd;
 121     hash_remove_link(hash, (hash_link *) fs);
 122     DEBUG(2)
 123     fprintf(stderr, "%d CLOSE id %d, FD %d, fs %p\n",
 124             (int) mypid,
 125             r->id,
 126             fs->fd,
 127             fs);
 128     xfree(fs);
 129     return close(fd);
 130 }
 131
 132 static int
 133 do_read(diomsg * r, int len, char *buf)
 134 {
 135     int x;
 136     int readlen = r->size;
 137     file_state *fs;
 138     fs = (file_state *) hash_lookup(hash, &r->id);
 139
 140     if (NULL == fs) {
 141         errno = EBADF;
 142         DEBUG(1) {
 143             fprintf(stderr, "%d READ  id %d: ", (int) mypid, r->id);
 144             perror("do_read");
 145         }
 146
 147         return -errno;
 148     }
 149
 150     if (r->offset > -1 && r->offset != fs->offset) {
 151         DEBUG(2)
 152         fprintf(stderr, "seeking to %"PRId64"\n", (int64_t)r->offset);
 153
 154         if (lseek(fs->fd, r->offset, SEEK_SET) < 0) {
 155             DEBUG(1) {
 156                 fprintf(stderr, "%d FD %d, offset %"PRId64": ", (int) mypid, fs->fd, (int64_t)r->offset);
 157                 perror("lseek");
 158             }
 159         }
 160     }
 161
 162     x = read(fs->fd, buf, readlen);
 163     DEBUG(2)
 164     fprintf(stderr, "%d READ %d,%d,%"PRId64" ret %d\n", (int) mypid,
 165             fs->fd, readlen, (int64_t)r->offset, x);
 166
 167     if (x < 0) {
 168         DEBUG(1) {
 169             fprintf(stderr, "%d FD %d: ", (int) mypid, fs->fd);
 170             perror("read");
 171         }
 172
 173         return -errno;
 174     }
 175
 176     fs->offset = r->offset + x;
 177     return x;
 178 }
 179
 180 static int
 181 do_write(diomsg * r, int len, const char *buf)
 182 {
 183     int wrtlen = r->size;
 184     int x;
 185     file_state *fs;
 186     fs = (file_state *) hash_lookup(hash, &r->id);
 187
 188     if (NULL == fs) {
 189         errno = EBADF;
 190         DEBUG(1) {
 191             fprintf(stderr, "%d WRITE id %d: ", (int) mypid, r->id);
 192             perror("do_write");
 193         }
 194
 195         return -errno;
 196     }
 197
 198     if (r->offset > -1 && r->offset != fs->offset) {
 199         if (lseek(fs->fd, r->offset, SEEK_SET) < 0) {
 200             DEBUG(1) {
 201                 fprintf(stderr, "%d FD %d, offset %"PRId64": ", (int) mypid, fs->fd, (int64_t)r->offset);
 202                 perror("lseek");
 203             }
 204         }
 205     }
 206
 207     DEBUG(2)
 208     fprintf(stderr, "%d WRITE %d,%d,%"PRId64"\n", (int) mypid,
 209             fs->fd, wrtlen, (int64_t)r->offset);
 210     x = write(fs->fd, buf, wrtlen);
 211
 212     if (x < 0) {
 213         DEBUG(1) {
 214             fprintf(stderr, "%d FD %d: ", (int) mypid, fs->fd);
 215             perror("write");
 216         }
 217
 218         return -errno;
 219     }
 220
 221     fs->offset = r->offset + x;
 222     return x;
 223 }
 224
 225 static int
 226 do_unlink(diomsg * r, int len, const char *buf)
 227 {
 228     if (unlink(buf) < 0) {
 229         DEBUG(1) {
 230             fprintf(stderr, "%d UNLNK id %d %s: ", (int) mypid, r->id, buf);
 231             perror("unlink");
 232         }
 233
 234         return -errno;
 235     }
 236
 237     DEBUG(2)
 238     fprintf(stderr, "%d UNLNK %s\n", (int) mypid, buf);
 239     return 0;
 240 }
 241
 242 static void
 243 msg_handle(diomsg * r, int rl, diomsg * s)
 244 {
 245     char *buf = NULL;
 246     s->mtype = r->mtype;
 247     s->id = r->id;
 248     s->seq_no = r->seq_no;      /* optional, debugging */
 249     s->callback_data = r->callback_data;
 250     s->requestor = r->requestor;
 251     s->size = 0;                /* optional, debugging */
 252     s->offset = 0;              /* optional, debugging */
 253     s->shm_offset = r->shm_offset;
 254     s->newstyle = r->newstyle;
 255
 256     if (s->shm_offset > -1)
 257         buf = shmbuf + s->shm_offset;
 258
 259     switch (r->mtype) {
 260
 261     case _MQD_OPEN:
 262
 263     case _MQD_CREATE:
 264         s->status = do_open(r, rl, buf);
 265         break;
 266
 267     case _MQD_CLOSE:
 268         s->status = do_close(r, rl);
 269         break;
 270
 271     case _MQD_READ:
 272         s->status = do_read(r, rl, buf);
 273         break;
 274
 275     case _MQD_WRITE:
 276         s->status = do_write(r, rl, buf);
 277         break;
 278
 279     case _MQD_UNLINK:
 280         s->status = do_unlink(r, rl, buf);
 281         break;
 282
 283     default:
 284         assert(0);
 285         break;
 286     }
 287 }
 288
 289 static int
 290 fsCmp(const void *a, const void *b)
 291 {
 292     const int *A = (const int *)a;
 293     const int *B = (const int *)b;
 294     return *A != *B;
 295 }
 296
 297 static unsigned int
 298 fsHash(const void *key, unsigned int n)
 299 {
 300     /* note, n must be a power of 2! */
 301     const int *k = (const int *)key;
 302     return (*k & (--n));
 303 }
 304
 305 SQUIDCEXTERN {
 306     static void
 307     alarm_handler(int sig) {
 308         (void) 0;
 309     }
 310 };
 311
 312 int
 313 main(int argc, char *argv[])
 314 {
 315     int key;
 316     int rmsgid;
 317     int smsgid;
 318     int shmid;
 319     diomsg rmsg;
 320     diomsg smsg;
 321     int rlen;
 322     char rbuf[512];
 323
 324     struct sigaction sa;
 325     setbuf(stdout, NULL);
 326     setbuf(stderr, NULL);
 327     mypid = getpid();
 328     assert(4 == argc);
 329     key = atoi(argv[1]);
 330     rmsgid = msgget(key, 0600);
 331
 332     if (rmsgid < 0) {
 333         perror("msgget");
 334         return 1;
 335     }
 336
 337     key = atoi(argv[2]);
 338     smsgid = msgget(key, 0600);
 339
 340     if (smsgid < 0) {
 341         perror("msgget");
 342         return 1;
 343     }
 344
 345     key = atoi(argv[3]);
 346     shmid = shmget(key, 0, 0600);
 347
 348     if (shmid < 0) {
 349         perror("shmget");
 350         return 1;
 351     }
 352
 353     shmbuf = (char *)shmat(shmid, NULL, 0);
 354
 355     if (shmbuf == (void *) -1) {
 356         perror("shmat");
 357         return 1;
 358     }
 359
 360     hash = hash_create(fsCmp, 1 << 4, fsHash);
 361     assert(hash);
 362     fcntl(0, F_SETFL, SQUID_NONBLOCK);
 363     memset(&sa, '\0', sizeof(sa));
 364     sa.sa_handler = alarm_handler;
 365     sa.sa_flags = SA_RESTART;
 366     sigaction(SIGALRM, &sa, NULL);
 367
 368     for (;;) {
 369         alarm(1);
 370         memset(&rmsg, '\0', sizeof(rmsg));
 371         DEBUG(2)
 372         std::cerr << "msgrcv: " << rmsgid << ", "
 373                   << &rmsg << ", " << diomsg::msg_snd_rcv_sz
 374                   << ", " << 0 << ", " << 0 << std::endl;
 375         rlen = msgrcv(rmsgid, &rmsg, diomsg::msg_snd_rcv_sz, 0, 0);
 376
 377         if (rlen < 0) {
 378             if (EINTR == errno) {
 379                 if (read(0, rbuf, 512) <= 0) {
 380                     if (EWOULDBLOCK == errno)
 381                         (void) 0;
 382                     else if (EAGAIN == errno)
 383                         (void) 0;
 384                     else
 385                         break;
 386                 }
 387             }
 388
 389             if (EAGAIN == errno) {
 390                 continue;
 391             }
 392
 393             perror("msgrcv");
 394             break;
 395         }
 396
 397         alarm(0);
 398         msg_handle(&rmsg, rlen, &smsg);
 399
 400         if (msgsnd(smsgid, &smsg, diomsg::msg_snd_rcv_sz, 0) < 0) {
 401             perror("msgsnd");
 402             break;
 403         }
 404     }
 405
 406     DEBUG(2)
 407     fprintf(stderr, "%d diskd exiting\n", (int) mypid);
 408
 409     if (msgctl(rmsgid, IPC_RMID, 0) < 0)
 410         perror("msgctl IPC_RMID");
 411
 412     if (msgctl(smsgid, IPC_RMID, 0) < 0)
 413         perror("msgctl IPC_RMID");
 414
 415     if (shmdt(shmbuf) < 0)
 416         perror("shmdt");
 417
 418     if (shmctl(shmid, IPC_RMID, 0) < 0)
 419         perror("shmctl IPC_RMID");
 420
 421     return 0;
 422 }