bin/cpdup/hclink.c

   1 /*
   2  * HCLINK.C
   3  *
   4  * This module implements a simple remote control protocol
   5  *
   6  * $DragonFly: src/bin/cpdup/hclink.c,v 1.10 2008/05/24 17:21:36 dillon Exp $
   7  */
   8
   9 #include "cpdup.h"
  10 #include "hclink.h"
  11 #include "hcproto.h"
  12
  13 static void hcc_start_reply(hctransaction_t trans, struct HCHead *rhead);
  14 static int hcc_finish_reply(hctransaction_t trans, struct HCHead *head);
  15
  16 int
  17 hcc_connect(struct HostConf *hc, int readonly)
  18 {
  19     int fdin[2];
  20     int fdout[2];
  21     const char *av[32];
  22
  23     if (hc == NULL || hc->host == NULL)
  24         return(0);
  25
  26     if (pipe(fdin) < 0)
  27         return(-1);
  28     if (pipe(fdout) < 0) {
  29         close(fdin[0]);
  30         close(fdin[1]);
  31         return(-1);
  32     }
  33     if ((hc->pid = fork()) == 0) {
  34         /*
  35          * Child process
  36          */
  37         int n, m;
  38
  39         dup2(fdin[1], 1);
  40         close(fdin[0]);
  41         close(fdin[1]);
  42         dup2(fdout[0], 0);
  43         close(fdout[0]);
  44         close(fdout[1]);
  45
  46         n = 0;
  47         av[n++] = "ssh";
  48         if (CompressOpt)
  49             av[n++] = "-C";
  50         for (m = 0; m < ssh_argc; m++)
  51             av[n++] = ssh_argv[m];
  52         av[n++] = "-T";
  53         av[n++] = hc->host;
  54         av[n++] = "cpdup";
  55         av[n++] = (readonly ? "-RS" : "-S");
  56         av[n++] = NULL;
  57
  58         execv("/usr/bin/ssh", (void *)av);
  59         _exit(1);
  60     } else if (hc->pid < 0) {
  61         return(-1);
  62     } else {
  63         /*
  64          * Parent process.  Do the initial handshake to make sure we are
  65          * actually talking to a cpdup slave.
  66          */
  67         close(fdin[1]);
  68         hc->fdin = fdin[0];
  69         close(fdout[0]);
  70         hc->fdout = fdout[1];
  71         return(0);
  72     }
  73 }
  74
  75 static int
  76 rc_badop(hctransaction_t trans __unused, struct HCHead *head)
  77 {
  78     head->error = EOPNOTSUPP;
  79     return(0);
  80 }
  81
  82 int
  83 hcc_slave(int fdin, int fdout, struct HCDesc *descs, int count)
  84 {
  85     struct HostConf hcslave;
  86     struct HCHead *head;
  87     struct HCTransaction trans;
  88     int (*dispatch[256])(hctransaction_t, struct HCHead *);
  89     int i;
  90     int r;
  91
  92     bzero(&hcslave, sizeof(hcslave));
  93     bzero(&trans, sizeof(trans));
  94     bzero(dispatch, sizeof(dispatch));
  95     for (i = 0; i < count; ++i) {
  96         struct HCDesc *desc = &descs[i];
  97         assert(desc->cmd >= 0 && desc->cmd < 256);
  98         dispatch[desc->cmd] = desc->func;
  99     }
 100     for (i = 0; i < 256; ++i) {
 101         if (dispatch[i] == NULL)
 102             dispatch[i] = rc_badop;
 103     }
 104     hcslave.fdin = fdin;
 105     hcslave.fdout = fdout;
 106     trans.hc = &hcslave;
 107
 108     /*
 109      * Process commands on fdin and write out results on fdout
 110      */
 111     for (;;) {
 112         /*
 113          * Get the command
 114          */
 115         head = hcc_read_command(trans.hc, &trans);
 116         if (head == NULL)
 117             break;
 118
 119         /*
 120          * Start the reply and dispatch, then process the return code.
 121          */
 122         head->error = 0;
 123         hcc_start_reply(&trans, head);
 124
 125         r = dispatch[head->cmd & 255](&trans, head);
 126
 127         switch(r) {
 128         case -2:
 129                 head->error = EINVAL;
 130                 break;
 131         case -1:
 132                 head->error = errno;
 133                 break;
 134         case 0:
 135                 break;
 136         default:
 137                 assert(0);
 138                 break;
 139         }
 140
 141         if (!hcc_finish_reply(&trans, head))
 142             break;
 143     }
 144     return(0);
 145 }
 146
 147 /*
 148  * This reads a command from fdin, fixes up the byte ordering, and returns
 149  * a pointer to HCHead.
 150  */
 151 struct HCHead *
 152 hcc_read_command(struct HostConf *hc, hctransaction_t trans)
 153 {
 154     struct HCHead tmp;
 155     int aligned_bytes;
 156     int need_swap;
 157     int n;
 158     int r;
 159
 160     if (trans == NULL)
 161         fatal("cpdup hlink protocol error with %s", hc->host);
 162
 163     n = 0;
 164     while (n < (int)sizeof(struct HCHead)) {
 165         r = read(hc->fdin, (char *)&tmp + n, sizeof(struct HCHead) - n);
 166         if (r <= 0)
 167             goto fail;
 168         n += r;
 169     }
 170
 171     if (tmp.magic == HCMAGIC) {
 172         need_swap = 0;
 173     } else {
 174         tmp.magic = hc_bswap32(tmp.magic);
 175         if (tmp.magic != HCMAGIC)
 176             fatal("magic mismatch with %s (%04x)", hc->host, tmp.id);
 177         need_swap = 1;
 178         tmp.bytes = hc_bswap32(tmp.bytes);
 179         tmp.cmd   = hc_bswap16(tmp.cmd);
 180         tmp.id    = hc_bswap16(tmp.id);
 181         tmp.error = hc_bswap32(tmp.error);
 182     }
 183
 184     assert(tmp.bytes >= (int)sizeof(tmp) && tmp.bytes < HC_BUFSIZE);
 185
 186     trans->swap = need_swap;
 187     bcopy(&tmp, trans->rbuf, n);
 188     aligned_bytes = HCC_ALIGN(tmp.bytes);
 189
 190     while (n < aligned_bytes) {
 191         r = read(hc->fdin, trans->rbuf + n, aligned_bytes - n);
 192         if (r <= 0)
 193             goto fail;
 194         n += r;
 195     }
 196 #ifdef DEBUG
 197     hcc_debug_dump(trans, head);
 198 #endif
 199     trans->state = HCT_REPLIED;
 200     return((void *)trans->rbuf);
 201 fail:
 202     trans->state = HCT_FAIL;
 203     return(NULL);
 204 }
 205
 206 /*
 207  * Initialize for a new command
 208  */
 209 hctransaction_t
 210 hcc_start_command(struct HostConf *hc, int16_t cmd)
 211 {
 212     struct HCHead *whead;
 213     hctransaction_t trans;
 214
 215     trans = &hc->trans;
 216
 217     whead = (void *)trans->wbuf;
 218     whead->magic = HCMAGIC;
 219     whead->bytes = 0;
 220     whead->cmd = cmd;
 221     whead->id = trans->id;
 222     whead->error = 0;
 223
 224     trans->windex = sizeof(*whead);
 225     trans->hc = hc;
 226     trans->state = HCT_IDLE;
 227
 228     return(trans);
 229 }
 230
 231 static void
 232 hcc_start_reply(hctransaction_t trans, struct HCHead *rhead)
 233 {
 234     struct HCHead *whead = (void *)trans->wbuf;
 235
 236     whead->magic = HCMAGIC;
 237     whead->bytes = 0;
 238     whead->cmd = rhead->cmd | HCF_REPLY;
 239     whead->id = rhead->id;
 240     whead->error = 0;
 241
 242     trans->windex = sizeof(*whead);
 243 }
 244
 245 /*
 246  * Finish constructing a command, transmit it, and await the reply.
 247  * Return the HCHead of the reply.
 248  */
 249 struct HCHead *
 250 hcc_finish_command(hctransaction_t trans)
 251 {
 252     struct HostConf *hc;
 253     struct HCHead *whead;
 254     struct HCHead *rhead;
 255     int aligned_bytes;
 256     int16_t wcmd;
 257
 258     hc = trans->hc;
 259     whead = (void *)trans->wbuf;
 260     whead->bytes = trans->windex;
 261     aligned_bytes = HCC_ALIGN(trans->windex);
 262     trans->windex = 0;  /* initialize for hcc_nextchaineditem() */
 263
 264     trans->state = HCT_SENT;
 265
 266     if (write(hc->fdout, whead, aligned_bytes) != aligned_bytes) {
 267 #ifdef __error
 268         *__error = EIO;
 269 #else
 270         errno = EIO;
 271 #endif
 272         if (whead->cmd < 0x0010)
 273             return(NULL);
 274         fatal("cpdup lost connection to %s", hc->host);
 275     }
 276
 277     wcmd = whead->cmd;
 278
 279     /*
 280      * whead is invalid when we call hcc_read_command() because
 281      * we may switch to another thread.
 282      */
 283     rhead = hcc_read_command(hc, trans);
 284     if (trans->state != HCT_REPLIED || rhead->id != trans->id) {
 285 #ifdef __error
 286         *__error = EIO;
 287 #else
 288         errno = EIO;
 289 #endif
 290         if (wcmd < 0x0010)
 291                 return(NULL);
 292         fatal("cpdup lost connection to %s", hc->host);
 293     }
 294     trans->state = HCT_DONE;
 295
 296     if (rhead->error) {
 297 #ifdef __error
 298         *__error = rhead->error;
 299 #else
 300         errno = rhead->error;
 301 #endif
 302     }
 303     return (rhead);
 304 }
 305
 306 int
 307 hcc_finish_reply(hctransaction_t trans, struct HCHead *head)
 308 {
 309     struct HCHead *whead;
 310     int aligned_bytes;
 311
 312     whead = (void *)trans->wbuf;
 313     whead->bytes = trans->windex;
 314     whead->error = head->error;
 315     aligned_bytes = HCC_ALIGN(trans->windex);
 316 #ifdef DEBUG
 317     hcc_debug_dump(trans, whead);
 318 #endif
 319     return (write(trans->hc->fdout, whead, aligned_bytes) == aligned_bytes);
 320 }
 321
 322 void
 323 hcc_leaf_string(hctransaction_t trans, int16_t leafid, const char *str)
 324 {
 325     struct HCLeaf *item;
 326     int bytes = strlen(str) + 1;
 327
 328     item = (void *)(trans->wbuf + trans->windex);
 329     assert(trans->windex + sizeof(*item) + bytes < HC_BUFSIZE);
 330     item->leafid = leafid;
 331     item->reserved = 0;
 332     item->bytes = sizeof(*item) + bytes;
 333     bcopy(str, item + 1, bytes);
 334     trans->windex = HCC_ALIGN(trans->windex + item->bytes);
 335 }
 336
 337 void
 338 hcc_leaf_data(hctransaction_t trans, int16_t leafid, const void *ptr, int bytes)
 339 {
 340     struct HCLeaf *item;
 341
 342     item = (void *)(trans->wbuf + trans->windex);
 343     assert(trans->windex + sizeof(*item) + bytes < HC_BUFSIZE);
 344     item->leafid = leafid;
 345     item->reserved = 0;
 346     item->bytes = sizeof(*item) + bytes;
 347     bcopy(ptr, item + 1, bytes);
 348     trans->windex = HCC_ALIGN(trans->windex + item->bytes);
 349 }
 350
 351 void
 352 hcc_leaf_int32(hctransaction_t trans, int16_t leafid, int32_t value)
 353 {
 354     struct HCLeaf *item;
 355
 356     item = (void *)(trans->wbuf + trans->windex);
 357     assert(trans->windex + sizeof(*item) + sizeof(value) < HC_BUFSIZE);
 358     item->leafid = leafid;
 359     item->reserved = 0;
 360     item->bytes = sizeof(*item) + sizeof(value);
 361     *(int32_t *)(item + 1) = value;
 362     trans->windex = HCC_ALIGN(trans->windex + item->bytes);
 363 }
 364
 365 void
 366 hcc_leaf_int64(hctransaction_t trans, int16_t leafid, int64_t value)
 367 {
 368     struct HCLeaf *item;
 369
 370     item = (void *)(trans->wbuf + trans->windex);
 371     assert(trans->windex + sizeof(*item) + sizeof(value) < HC_BUFSIZE);
 372     item->leafid = leafid;
 373     item->reserved = 0;
 374     item->bytes = sizeof(*item) + sizeof(value);
 375     *(int64_t *)(item + 1) = value;
 376     trans->windex = HCC_ALIGN(trans->windex + item->bytes);
 377 }
 378
 379 /*
 380  * Check if there's enough space left in the write buffer for <n>
 381  * leaves with a total of <size> data bytes.
 382  * If not, the current packet will be sent with the HCF_CONTINUE flag,
 383  * then the transaction is initialized for another reply packet.
 384  *
 385  * Returns success status (boolean).
 386  */
 387 int
 388 hcc_check_space(hctransaction_t trans, struct HCHead *head, int n, int size)
 389 {
 390     size = HCC_ALIGN(size) + n * sizeof(struct HCLeaf);
 391     if (size >= HC_BUFSIZE - trans->windex) {
 392         struct HCHead *whead = (void *)trans->wbuf;
 393
 394         whead->cmd |= HCF_CONTINUE;
 395         if (!hcc_finish_reply(trans, head))
 396             return (0);
 397         hcc_start_reply(trans, head);
 398     }
 399     return (1);
 400 }
 401
 402 intptr_t
 403 hcc_alloc_descriptor(struct HostConf *hc, void *ptr, int type)
 404 {
 405     struct HCHostDesc *hd;
 406     struct HCHostDesc *hnew;
 407
 408     hnew = malloc(sizeof(struct HCHostDesc));
 409     hnew->type = type;
 410     hnew->data = ptr;
 411
 412     if ((hd = hc->hostdescs) != NULL) {
 413         hnew->desc = hd->desc + 1;
 414     } else {
 415         /* start at 2 because 1 has a special meaning in hc_open() */
 416         hnew->desc = 2;
 417     }
 418     hnew->next = hd;
 419     hc->hostdescs = hnew;
 420     return(hnew->desc);
 421 }
 422
 423 void *
 424 hcc_get_descriptor(struct HostConf *hc, intptr_t desc, int type)
 425 {
 426     struct HCHostDesc *hd;
 427
 428     for (hd = hc->hostdescs; hd; hd = hd->next) {
 429         if (hd->desc == desc && hd->type == type)
 430             return(hd->data);
 431     }
 432     return(NULL);
 433 }
 434
 435 void
 436 hcc_set_descriptor(struct HostConf *hc, intptr_t desc, void *ptr, int type)
 437 {
 438     struct HCHostDesc *hd;
 439     struct HCHostDesc **hdp;
 440
 441     for (hdp = &hc->hostdescs; (hd = *hdp) != NULL; hdp = &hd->next) {
 442         if (hd->desc == desc) {
 443             if (ptr) {
 444                 hd->data = ptr;
 445                 hd->type = type;
 446             } else {
 447                 *hdp = hd->next;
 448                 free(hd);
 449             }
 450             return;
 451         }
 452     }
 453     if (ptr) {
 454         hd = malloc(sizeof(*hd));
 455         hd->desc = desc;
 456         hd->type = type;
 457         hd->data = ptr;
 458         hd->next = hc->hostdescs;
 459         hc->hostdescs = hd;
 460     }
 461 }
 462
 463 struct HCLeaf *
 464 hcc_nextitem(hctransaction_t trans, struct HCHead *head, struct HCLeaf *item)
 465 {
 466     int offset;
 467
 468     if (item == NULL)
 469         item = (void *)(head + 1);
 470     else
 471         item = (void *)((char *)item + HCC_ALIGN(item->bytes));
 472     offset = (char *)item - (char *)head;
 473     if (offset == head->bytes)
 474         return(NULL);
 475     if (trans->swap) {
 476         int64_t *i64ptr;
 477         int32_t *i32ptr;
 478
 479         item->leafid = hc_bswap16(item->leafid);
 480         item->bytes  = hc_bswap32(item->bytes);
 481         switch (item->leafid & LCF_TYPEMASK) {
 482             case LCF_INT32:
 483                 i32ptr = (void *)(item + 1);
 484                 *i32ptr = hc_bswap32(*i32ptr);
 485                 break;
 486             case LCF_INT64:
 487                 i64ptr = (void *)(item + 1);
 488                 *i64ptr = hc_bswap64(*i64ptr);
 489                 break;
 490         }
 491     }
 492     assert(head->bytes >= offset + (int)sizeof(*item));
 493     assert(head->bytes >= offset + item->bytes);
 494     assert(item->bytes >= (int)sizeof(*item) && item->bytes < HC_BUFSIZE);
 495     return (item);
 496 }
 497
 498 struct HCLeaf *
 499 hcc_nextchaineditem(struct HostConf *hc, struct HCHead *head)
 500 {
 501     hctransaction_t trans = &hc->trans;
 502     struct HCLeaf *item = hcc_currentchaineditem(hc, head);
 503
 504     while ((item = hcc_nextitem(trans, head, item)) == NULL) {
 505         if (!(head->cmd & HCF_CONTINUE))
 506             return (NULL);
 507         head = hcc_read_command(hc, trans);
 508         if (trans->state != HCT_REPLIED || head->id != trans->id)
 509             return (NULL);
 510     }
 511     trans->windex = (char *)item - (char *)head;
 512     return (item);
 513 }
 514
 515 struct HCLeaf *
 516 hcc_currentchaineditem(struct HostConf *hc, struct HCHead *head)
 517 {
 518     hctransaction_t trans = &hc->trans;
 519
 520     if (trans->windex == 0)
 521         return (NULL);
 522     else
 523         return ((void *) ((char *)head + trans->windex));
 524 }
 525
 526 #ifdef DEBUG
 527
 528 void
 529 hcc_debug_dump(hctransaction_t trans, struct HCHead *head)
 530 {
 531     struct HCLeaf *item;
 532     int aligned_bytes = HCC_ALIGN(head->bytes);
 533
 534     fprintf(stderr, "DUMP %04x (%d)", (uint16_t)head->cmd, aligned_bytes);
 535     if (head->cmd & HCF_REPLY)
 536         fprintf(stderr, " error %d", head->error);
 537     fprintf(stderr, "\n");
 538     FOR_EACH_ITEM(item, trans, head) {
 539         fprintf(stderr, "    ITEM %04x DATA ", item->leafid);
 540         switch(item->leafid & LCF_TYPEMASK) {
 541         case LCF_INT32:
 542             fprintf(stderr, "int32 %d\n", HCC_INT32(item));
 543             break;
 544         case LCF_INT64:
 545             fprintf(stderr, "int64 %lld\n", HCC_INT64(item));
 546             break;
 547         case LCF_STRING:
 548             fprintf(stderr, "\"%s\"\n", HCC_STRING(item));
 549             break;
 550         case LCF_BINARY:
 551             fprintf(stderr, "(binary)\n");
 552             break;
 553         default:
 554             printf("?\n");
 555         }
 556     }
 557 }
 558
 559 #endif