contrib/sendmail-8.14/libsm/exc.c

   1 /*
   2  * Copyright (c) 2000-2002 Sendmail, Inc. and its suppliers.
   3  *      All rights reserved.
   4  *
   5  * By using this file, you agree to the terms and conditions set
   6  * forth in the LICENSE file which can be found at the top level of
   7  * the sendmail distribution.
   8  *
   9  */
  10
  11 #include <sm/gen.h>
  12 SM_RCSID("@(#)$Id: exc.c,v 1.49 2006/12/19 19:28:09 ca Exp $")
  13
  14 /*
  15 **  exception handling
  16 **  For documentation, see exc.html
  17 */
  18
  19 #include <ctype.h>
  20 #include <string.h>
  21
  22 #include <sm/errstring.h>
  23 #include <sm/exc.h>
  24 #include <sm/heap.h>
  25 #include <sm/string.h>
  26 #include <sm/varargs.h>
  27 #include <sm/io.h>
  28
  29 const char SmExcMagic[] = "sm_exc";
  30 const char SmExcTypeMagic[] = "sm_exc_type";
  31
  32 /*
  33 **  SM_ETYPE_PRINTF -- printf for exception types.
  34 **
  35 **      Parameters:
  36 **              exc -- exception.
  37 **              stream -- file for output.
  38 **
  39 **      Returns:
  40 **              none.
  41 */
  42
  43 /*
  44 **  A simple formatted print function that can be used as the print function
  45 **  by most exception types.  It prints the printcontext string, interpreting
  46 **  occurrences of %0 through %9 as references to the argument vector.
  47 **  If exception argument 3 is an int or long, then %3 will print the
  48 **  argument in decimal, and %o3 or %x3 will print it in octal or hex.
  49 */
  50
  51 void
  52 sm_etype_printf(exc, stream)
  53         SM_EXC_T *exc;
  54         SM_FILE_T *stream;
  55 {
  56         size_t n = strlen(exc->exc_type->etype_argformat);
  57         const char *p, *s;
  58         char format;
  59
  60         for (p = exc->exc_type->etype_printcontext; *p != '\0'; ++p)
  61         {
  62                 if (*p != '%')
  63                 {
  64                         (void) sm_io_putc(stream, SM_TIME_DEFAULT, *p);
  65                         continue;
  66                 }
  67                 ++p;
  68                 if (*p == '\0')
  69                 {
  70                         (void) sm_io_putc(stream, SM_TIME_DEFAULT, '%');
  71                         break;
  72                 }
  73                 if (*p == '%')
  74                 {
  75                         (void) sm_io_putc(stream, SM_TIME_DEFAULT, '%');
  76                         continue;
  77                 }
  78                 format = '\0';
  79                 if (isalpha(*p))
  80                 {
  81                         format = *p++;
  82                         if (*p == '\0')
  83                         {
  84                                 (void) sm_io_putc(stream, SM_TIME_DEFAULT, '%');
  85                                 (void) sm_io_putc(stream, SM_TIME_DEFAULT,
  86                                                   format);
  87                                 break;
  88                         }
  89                 }
  90                 if (isdigit(*p))
  91                 {
  92                         size_t i = *p - '0';
  93                         if (i < n)
  94                         {
  95                                 switch (exc->exc_type->etype_argformat[i])
  96                                 {
  97                                   case 's':
  98                                   case 'r':
  99                                         s = exc->exc_argv[i].v_str;
 100                                         if (s == NULL)
 101                                                 s = "(null)";
 102                                         sm_io_fputs(stream, SM_TIME_DEFAULT, s);
 103                                         continue;
 104                                   case 'i':
 105                                         sm_io_fprintf(stream,
 106                                                 SM_TIME_DEFAULT,
 107                                                 format == 'o' ? "%o"
 108                                                 : format == 'x' ? "%x"
 109                                                                 : "%d",
 110                                                 exc->exc_argv[i].v_int);
 111                                         continue;
 112                                   case 'l':
 113                                         sm_io_fprintf(stream,
 114                                                 SM_TIME_DEFAULT,
 115                                                 format == 'o' ? "%lo"
 116                                                 : format == 'x' ? "%lx"
 117                                                                 : "%ld",
 118                                                 exc->exc_argv[i].v_long);
 119                                         continue;
 120                                   case 'e':
 121                                         sm_exc_write(exc->exc_argv[i].v_exc,
 122                                                 stream);
 123                                         continue;
 124                                 }
 125                         }
 126                 }
 127                 (void) sm_io_putc(stream, SM_TIME_DEFAULT, '%');
 128                 if (format)
 129                         (void) sm_io_putc(stream, SM_TIME_DEFAULT, format);
 130                 (void) sm_io_putc(stream, SM_TIME_DEFAULT, *p);
 131         }
 132 }
 133
 134 /*
 135 **  Standard exception types.
 136 */
 137
 138 /*
 139 **  SM_ETYPE_OS_PRINT -- Print OS related exception.
 140 **
 141 **      Parameters:
 142 **              exc -- exception.
 143 **              stream -- file for output.
 144 **
 145 **      Returns:
 146 **              none.
 147 */
 148
 149 static void
 150 sm_etype_os_print __P((
 151         SM_EXC_T *exc,
 152         SM_FILE_T *stream));
 153
 154 static void
 155 sm_etype_os_print(exc, stream)
 156         SM_EXC_T *exc;
 157         SM_FILE_T *stream;
 158 {
 159         int err = exc->exc_argv[0].v_int;
 160         char *syscall = exc->exc_argv[1].v_str;
 161         char *sysargs = exc->exc_argv[2].v_str;
 162
 163         if (sysargs)
 164                 sm_io_fprintf(stream, SM_TIME_DEFAULT, "%s: %s failed: %s",
 165                               sysargs, syscall, sm_errstring(err));
 166         else
 167                 sm_io_fprintf(stream, SM_TIME_DEFAULT, "%s failed: %s", syscall,
 168                               sm_errstring(err));
 169 }
 170
 171 /*
 172 **  SmEtypeOs represents the failure of a Unix system call.
 173 **  The three arguments are:
 174 **   int errno (eg, ENOENT)
 175 **   char *syscall (eg, "open")
 176 **   char *sysargs (eg, NULL or "/etc/mail/sendmail.cf")
 177 */
 178
 179 const SM_EXC_TYPE_T SmEtypeOs =
 180 {
 181         SmExcTypeMagic,
 182         "E:sm.os",
 183         "isr",
 184         sm_etype_os_print,
 185         NULL,
 186 };
 187
 188 /*
 189 **  SmEtypeErr is a completely generic error which should only be
 190 **  used in applications and test programs.  Libraries should use
 191 **  more specific exception codes.
 192 */
 193
 194 const SM_EXC_TYPE_T SmEtypeErr =
 195 {
 196         SmExcTypeMagic,
 197         "E:sm.err",
 198         "r",
 199         sm_etype_printf,
 200         "%0",
 201 };
 202
 203 /*
 204 **  SM_EXC_VNEW_X -- Construct a new exception object.
 205 **
 206 **      Parameters:
 207 **              etype -- type of exception.
 208 **              ap -- varargs.
 209 **
 210 **      Returns:
 211 **              pointer to exception object.
 212 */
 213
 214 /*
 215 **  This is an auxiliary function called by sm_exc_new_x and sm_exc_raisenew_x.
 216 **
 217 **  If an exception is raised, then to avoid a storage leak, we must:
 218 **  (a) Free all storage we have allocated.
 219 **  (b) Free all exception arguments in the varargs list.
 220 **  Getting this right is tricky.
 221 **
 222 **  To see why (b) is required, consider the code fragment
 223 **     SM_EXCEPT(exc, "*")
 224 **         sm_exc_raisenew_x(&MyEtype, exc);
 225 **     SM_END_TRY
 226 **  In the normal case, sm_exc_raisenew_x will allocate and raise a new
 227 **  exception E that owns exc.  When E is eventually freed, exc is also freed.
 228 **  In the exceptional case, sm_exc_raisenew_x must free exc before raising
 229 **  an out-of-memory exception so that exc is not leaked.
 230 */
 231
 232 static SM_EXC_T *sm_exc_vnew_x __P((const SM_EXC_TYPE_T *, va_list SM_NONVOLATILE));
 233
 234 static SM_EXC_T *
 235 sm_exc_vnew_x(etype, ap)
 236         const SM_EXC_TYPE_T *etype;
 237         va_list SM_NONVOLATILE ap;
 238 {
 239         /*
 240         **  All variables that are modified in the SM_TRY clause and
 241         **  referenced in the SM_EXCEPT clause must be declared volatile.
 242         */
 243
 244         /* NOTE: Type of si, i, and argc *must* match */
 245         SM_EXC_T * volatile exc = NULL;
 246         int volatile si = 0;
 247         SM_VAL_T * volatile argv = NULL;
 248         int i, argc;
 249
 250         SM_REQUIRE_ISA(etype, SmExcTypeMagic);
 251         argc = strlen(etype->etype_argformat);
 252         SM_TRY
 253         {
 254                 /*
 255                 **  Step 1.  Allocate the exception structure.
 256                 **  On failure, scan the varargs list and free all
 257                 **  exception arguments.
 258                 */
 259
 260                 exc = sm_malloc_x(sizeof(SM_EXC_T));
 261                 exc->sm_magic = SmExcMagic;
 262                 exc->exc_refcount = 1;
 263                 exc->exc_type = etype;
 264                 exc->exc_argv = NULL;
 265
 266                 /*
 267                 **  Step 2.  Allocate the argument vector.
 268                 **  On failure, free exc, scan the varargs list and free all
 269                 **  exception arguments.  On success, scan the varargs list,
 270                 **  and copy the arguments into argv.
 271                 */
 272
 273                 argv = sm_malloc_x(argc * sizeof(SM_VAL_T));
 274                 exc->exc_argv = argv;
 275                 for (i = 0; i < argc; ++i)
 276                 {
 277                         switch (etype->etype_argformat[i])
 278                         {
 279                           case 'i':
 280                                 argv[i].v_int = SM_VA_ARG(ap, int);
 281                                 break;
 282                           case 'l':
 283                                 argv[i].v_long = SM_VA_ARG(ap, long);
 284                                 break;
 285                           case 'e':
 286                                 argv[i].v_exc = SM_VA_ARG(ap, SM_EXC_T*);
 287                                 break;
 288                           case 's':
 289                                 argv[i].v_str = SM_VA_ARG(ap, char*);
 290                                 break;
 291                           case 'r':
 292                                 SM_REQUIRE(etype->etype_argformat[i+1] == '\0');
 293                                 argv[i].v_str = SM_VA_ARG(ap, char*);
 294                                 break;
 295                           default:
 296                                 sm_abort("sm_exc_vnew_x: bad argformat '%c'",
 297                                         etype->etype_argformat[i]);
 298                         }
 299                 }
 300
 301                 /*
 302                 **  Step 3.  Scan argv, and allocate space for all
 303                 **  string arguments.  si is the number of elements
 304                 **  of argv that have been processed so far.
 305                 **  On failure, free exc, argv, all the exception arguments
 306                 **  and all of the strings that have been copied.
 307                 */
 308
 309                 for (si = 0; si < argc; ++si)
 310                 {
 311                         switch (etype->etype_argformat[si])
 312                         {
 313                           case 's':
 314                             {
 315                                 char *str = argv[si].v_str;
 316                                 if (str != NULL)
 317                                     argv[si].v_str = sm_strdup_x(str);
 318                             }
 319                             break;
 320                           case 'r':
 321                             {
 322                                 char *fmt = argv[si].v_str;
 323                                 if (fmt != NULL)
 324                                     argv[si].v_str = sm_vstringf_x(fmt, ap);
 325                             }
 326                             break;
 327                         }
 328                 }
 329         }
 330         SM_EXCEPT(e, "*")
 331         {
 332                 if (exc == NULL || argv == NULL)
 333                 {
 334                         /*
 335                         **  Failure in step 1 or step 2.
 336                         **  Scan ap and free all exception arguments.
 337                         */
 338
 339                         for (i = 0; i < argc; ++i)
 340                         {
 341                                 switch (etype->etype_argformat[i])
 342                                 {
 343                                   case 'i':
 344                                         (void) SM_VA_ARG(ap, int);
 345                                         break;
 346                                   case 'l':
 347                                         (void) SM_VA_ARG(ap, long);
 348                                         break;
 349                                   case 'e':
 350                                         sm_exc_free(SM_VA_ARG(ap, SM_EXC_T*));
 351                                         break;
 352                                   case 's':
 353                                   case 'r':
 354                                         (void) SM_VA_ARG(ap, char*);
 355                                         break;
 356                                 }
 357                         }
 358                 }
 359                 else
 360                 {
 361                         /*
 362                         **  Failure in step 3.  Scan argv and free
 363                         **  all exception arguments and all string
 364                         **  arguments that have been duplicated.
 365                         **  Then free argv.
 366                         */
 367
 368                         for (i = 0; i < argc; ++i)
 369                         {
 370                                 switch (etype->etype_argformat[i])
 371                                 {
 372                                   case 'e':
 373                                         sm_exc_free(argv[i].v_exc);
 374                                         break;
 375                                   case 's':
 376                                   case 'r':
 377                                         if (i < si)
 378                                                 sm_free(argv[i].v_str);
 379                                         break;
 380                                 }
 381                         }
 382                         sm_free(argv);
 383                 }
 384                 sm_free(exc);
 385                 sm_exc_raise_x(e);
 386         }
 387         SM_END_TRY
 388
 389         return exc;
 390 }
 391
 392 /*
 393 **  SM_EXC_NEW_X -- Construct a new exception object.
 394 **
 395 **      Parameters:
 396 **              etype -- type of exception.
 397 **              ... -- varargs.
 398 **
 399 **      Returns:
 400 **              pointer to exception object.
 401 */
 402
 403 SM_EXC_T *
 404 #if SM_VA_STD
 405 sm_exc_new_x(
 406         const SM_EXC_TYPE_T *etype,
 407         ...)
 408 #else /* SM_VA_STD */
 409 sm_exc_new_x(etype, va_alist)
 410         const SM_EXC_TYPE_T *etype;
 411         va_dcl
 412 #endif /* SM_VA_STD */
 413 {
 414         SM_EXC_T *exc;
 415         SM_VA_LOCAL_DECL
 416
 417         SM_VA_START(ap, etype);
 418         exc = sm_exc_vnew_x(etype, ap);
 419         SM_VA_END(ap);
 420         return exc;
 421 }
 422
 423 /*
 424 **  SM_EXC_FREE -- Destroy a reference to an exception object.
 425 **
 426 **      Parameters:
 427 **              exc -- exception object.
 428 **
 429 **      Returns:
 430 **              none.
 431 */
 432
 433 void
 434 sm_exc_free(exc)
 435         SM_EXC_T *exc;
 436 {
 437         if (exc == NULL)
 438                 return;
 439         SM_REQUIRE(exc->sm_magic == SmExcMagic);
 440         if (exc->exc_refcount == 0)
 441                 return;
 442         if (--exc->exc_refcount == 0)
 443         {
 444                 int i, c;
 445
 446                 for (i = 0; (c = exc->exc_type->etype_argformat[i]) != '\0';
 447                      ++i)
 448                 {
 449                         switch (c)
 450                         {
 451                           case 's':
 452                           case 'r':
 453                                 sm_free(exc->exc_argv[i].v_str);
 454                                 break;
 455                           case 'e':
 456                                 sm_exc_free(exc->exc_argv[i].v_exc);
 457                                 break;
 458                         }
 459                 }
 460                 exc->sm_magic = NULL;
 461                 sm_free(exc->exc_argv);
 462                 sm_free(exc);
 463         }
 464 }
 465
 466 /*
 467 **  SM_EXC_MATCH -- Match exception category against a glob pattern.
 468 **
 469 **      Parameters:
 470 **              exc -- exception.
 471 **              pattern -- glob pattern.
 472 **
 473 **      Returns:
 474 **              true iff match.
 475 */
 476
 477 bool
 478 sm_exc_match(exc, pattern)
 479         SM_EXC_T *exc;
 480         const char *pattern;
 481 {
 482         if (exc == NULL)
 483                 return false;
 484         SM_REQUIRE(exc->sm_magic == SmExcMagic);
 485         return sm_match(exc->exc_type->etype_category, pattern);
 486 }
 487
 488 /*
 489 **  SM_EXC_WRITE -- Write exception message to a stream (wo trailing newline).
 490 **
 491 **      Parameters:
 492 **              exc -- exception.
 493 **              stream -- file for output.
 494 **
 495 **      Returns:
 496 **              none.
 497 */
 498
 499 void
 500 sm_exc_write(exc, stream)
 501         SM_EXC_T *exc;
 502         SM_FILE_T *stream;
 503 {
 504         SM_REQUIRE_ISA(exc, SmExcMagic);
 505         exc->exc_type->etype_print(exc, stream);
 506 }
 507
 508 /*
 509 **  SM_EXC_PRINT -- Print exception message to a stream (with trailing newline).
 510 **
 511 **      Parameters:
 512 **              exc -- exception.
 513 **              stream -- file for output.
 514 **
 515 **      Returns:
 516 **              none.
 517 */
 518
 519 void
 520 sm_exc_print(exc, stream)
 521         SM_EXC_T *exc;
 522         SM_FILE_T *stream;
 523 {
 524         SM_REQUIRE_ISA(exc, SmExcMagic);
 525         exc->exc_type->etype_print(exc, stream);
 526         (void) sm_io_putc(stream, SM_TIME_DEFAULT, '\n');
 527 }
 528
 529 SM_EXC_HANDLER_T *SmExcHandler = NULL;
 530 static SM_EXC_DEFAULT_HANDLER_T SmExcDefaultHandler = NULL;
 531
 532 /*
 533 **  SM_EXC_NEWTHREAD -- Initialize exception handling for new process/thread.
 534 **
 535 **      Parameters:
 536 **              h -- default exception handler.
 537 **
 538 **      Returns:
 539 **              none.
 540 */
 541
 542 /*
 543 **  Initialize a new process or a new thread by clearing the
 544 **  exception handler stack and optionally setting a default
 545 **  exception handler function.  Call this at the beginning of main,
 546 **  or in a new process after calling fork, or in a new thread.
 547 **
 548 **  This function is a luxury, not a necessity.
 549 **  If h != NULL then you can get the same effect by
 550 **  wrapping the body of main, or the body of a forked child
 551 **  or a new thread in SM_TRY ... SM_EXCEPT(e,"*") h(e); SM_END_TRY.
 552 */
 553
 554 void
 555 sm_exc_newthread(h)
 556         SM_EXC_DEFAULT_HANDLER_T h;
 557 {
 558         SmExcHandler = NULL;
 559         SmExcDefaultHandler = h;
 560 }
 561
 562 /*
 563 **  SM_EXC_RAISE_X -- Raise an exception.
 564 **
 565 **      Parameters:
 566 **              exc -- exception.
 567 **
 568 **      Returns:
 569 **              doesn't.
 570 */
 571
 572 void SM_DEAD_D
 573 sm_exc_raise_x(exc)
 574         SM_EXC_T *exc;
 575 {
 576         SM_REQUIRE_ISA(exc, SmExcMagic);
 577
 578         if (SmExcHandler == NULL)
 579         {
 580                 if (SmExcDefaultHandler != NULL)
 581                 {
 582                         SM_EXC_DEFAULT_HANDLER_T h;
 583
 584                         /*
 585                         **  If defined, the default handler is expected
 586                         **  to terminate the current thread of execution
 587                         **  using exit() or pthread_exit().
 588                         **  If it instead returns normally, then we fall
 589                         **  through to the default case below.  If it
 590                         **  raises an exception, then sm_exc_raise_x is
 591                         **  re-entered and, because we set SmExcDefaultHandler
 592                         **  to NULL before invoking h, we will again
 593                         **  end up in the default case below.
 594                         */
 595
 596                         h = SmExcDefaultHandler;
 597                         SmExcDefaultHandler = NULL;
 598                         (*h)(exc);
 599                 }
 600
 601                 /*
 602                 **  No exception handler, so print the error and exit.
 603                 **  To override this behaviour on a program wide basis,
 604                 **  call sm_exc_newthread or put an exception handler in main().
 605                 **
 606                 **  XXX TODO: map the exception category to an exit code
 607                 **  XXX from <sysexits.h>.
 608                 */
 609
 610                 sm_exc_print(exc, smioerr);
 611                 exit(255);
 612         }
 613
 614         if (SmExcHandler->eh_value == NULL)
 615                 SmExcHandler->eh_value = exc;
 616         else
 617                 sm_exc_free(exc);
 618
 619         sm_longjmp_nosig(SmExcHandler->eh_context, 1);
 620 }
 621
 622 /*
 623 **  SM_EXC_RAISENEW_X -- shorthand for sm_exc_raise_x(sm_exc_new_x(...))
 624 **
 625 **      Parameters:
 626 **              etype -- type of exception.
 627 **              ap -- varargs.
 628 **
 629 **      Returns:
 630 **              none.
 631 */
 632
 633 void SM_DEAD_D
 634 #if SM_VA_STD
 635 sm_exc_raisenew_x(
 636         const SM_EXC_TYPE_T *etype,
 637         ...)
 638 #else
 639 sm_exc_raisenew_x(etype, va_alist)
 640         const SM_EXC_TYPE_T *etype;
 641         va_dcl
 642 #endif
 643 {
 644         SM_EXC_T *exc;
 645         SM_VA_LOCAL_DECL
 646
 647         SM_VA_START(ap, etype);
 648         exc = sm_exc_vnew_x(etype, ap);
 649         SM_VA_END(ap);
 650         sm_exc_raise_x(exc);
 651 }