mdw@git.distorted.org.uk Git - fwd/blob - file.c

   1 /* -*-c-*-
   2  *
   3  * $Id: file.c,v 1.6 2003/11/29 20:36:07 mdw Exp $
   4  *
   5  * File source and target
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: file.c,v $
  32  * Revision 1.6  2003/11/29 20:36:07  mdw
  33  * Privileged outgoing connections.
  34  *
  35  * Revision 1.5  2002/02/22 23:43:32  mdw
  36  * Call @xfree@ rather than @free@.
  37  *
  38  * Revision 1.4  2001/02/03 20:30:03  mdw
  39  * Support re-reading config files on SIGHUP.
  40  *
  41  * Revision 1.3  1999/12/22 15:43:47  mdw
  42  * Fix log messages.
  43  *
  44  * Revision 1.2  1999/10/22 22:47:13  mdw
  45  * New (empty) endpoint method required.
  46  *
  47  * Revision 1.1  1999/07/26 23:33:32  mdw
  48  * New sources and targets.
  49  *
  50  */
  51
  52 /*----- Header files ------------------------------------------------------*/
  53
  54 #include "config.h"
  55
  56 #include <ctype.h>
  57 #include <errno.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61
  62 #include <sys/types.h>
  63 #include <sys/stat.h>
  64 #include <unistd.h>
  65 #include <fcntl.h>
  66
  67 #include <mLib/alloc.h>
  68 #include <mLib/dstr.h>
  69 #include <mLib/fdflags.h>
  70 #include <mLib/sub.h>
  71
  72 #include "conf.h"
  73 #include "endpt.h"
  74 #include "fattr.h"
  75 #include "file.h"
  76 #include "fw.h"
  77 #include "reffd.h"
  78 #include "scan.h"
  79 #include "source.h"
  80 #include "target.h"
  81
  82 /*----- Data structures ---------------------------------------------------*/
  83
  84 /* --- File specification --- */
  85
  86 typedef struct fspec {
  87   unsigned type;
  88   union {
  89     reffd *fd;
  90     char *name;
  91   } u;
  92 } fspec;
  93
  94 #define FTYPE_GUESS 0u
  95 #define FTYPE_FD 1u
  96 #define FTYPE_NAME 2u
  97 #define FTYPE_NULL 3u
  98
  99 /* --- File options --- */
 100
 101 typedef struct fopts {
 102   unsigned of;
 103 } fopts;
 104
 105 /* --- File data block --- */
 106
 107 typedef struct fdata {
 108   fspec in, out;
 109   fattr fa;
 110   fopts fo;
 111 } fdata;
 112
 113 /* --- File source block --- */
 114
 115 typedef struct fsource {
 116   source s;
 117   fdata f;
 118 } fsource;
 119
 120 /* --- File target block --- */
 121
 122 typedef struct ftarget {
 123   target t;
 124   fdata f;
 125 } ftarget;
 126
 127 /*----- Static variables --------------------------------------------------*/
 128
 129 static fopts file_opts = { O_TRUNC };
 130
 131 static reffd *rstdin, *rstdout;
 132 static reffd *rnull;
 133
 134 /*----- File endpoint operations ------------------------------------------*/
 135
 136 /* --- @wclose@ --- */
 137
 138 static void fept_wclose(endpt *e)
 139 {
 140   if (e->out) {
 141     REFFD_DEC(e->out);
 142     e->out = 0;
 143   }
 144 }
 145
 146 /* --- @close@ --- */
 147
 148 static void fept_close(endpt *e)
 149 {
 150   if (e->in)
 151     REFFD_DEC(e->in);
 152   if (e->out)
 153     REFFD_DEC(e->out);
 154   fw_dec();
 155   DESTROY(e);
 156 }
 157
 158 /* --- Endpoint operations table --- */
 159
 160 static endpt_ops fept_ops = { 0, 0, fept_wclose, fept_close };
 161
 162 /*----- General operations on sources and targets -------------------------*/
 163
 164 /* --- @file_null@ --- *
 165  *
 166  * Arguments:   @void *p@ = an uninteresting argument
 167  *
 168  * Returns:     ---
 169  *
 170  * Use:         Removes the reference to @rnull@ when the file closes.
 171  */
 172
 173 static void file_null(void *p)
 174 {
 175   rnull = 0;
 176 }
 177
 178 /* --- @file_nullref@ --- *
 179  *
 180  * Arguments:   ---
 181  *
 182  * Returns:     A reference to a file descriptor open on /dev/null.
 183  *
 184  * Use:         Obtains a file descriptor for /dev/null.  The reference
 185  *              @rnull@ is `weak', so that I only have a descriptor open when
 186  *              I actually need one.
 187  */
 188
 189 static reffd *file_nullref(void)
 190 {
 191   if (rnull)
 192     REFFD_INC(rnull);
 193   else {
 194     int n;
 195     if ((n = open("/dev/null", O_RDWR)) < 0) {
 196       fw_log(-1, "couldn't open `/dev/null': %s", strerror(errno));
 197       return (0);
 198     }
 199     fdflags(n, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 200     rnull = reffd_init(n);
 201     reffd_handler(rnull, file_null, 0);
 202   }
 203   return (rnull);
 204 }
 205
 206 /* --- @file_fspec@ --- *
 207  *
 208  * Arguments:   @fspec *f@ = pointer to filespec to fill in
 209  *              @scanner *sc@ = pointer to scanner to read from
 210  *
 211  * Returns:     ---
 212  *
 213  * Use:         Reads in a file spec.
 214  */
 215
 216 static void file_fspec(fspec *f, scanner *sc)
 217 {
 218   int c = 0;
 219   unsigned type = FTYPE_GUESS;
 220   reffd *fd = 0;
 221
 222   /* --- Set up references to @stdin@ and @stdout@ --- */
 223
 224   if (!rstdin) {
 225     fdflags(STDIN_FILENO, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 226     fdflags(STDOUT_FILENO, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 227     rstdin = reffd_init(STDIN_FILENO);
 228     rstdout = reffd_init(STDOUT_FILENO);
 229   }
 230
 231   /* --- Try to get an access type --- */
 232
 233   if (sc->t == ':') {
 234     c = 1;
 235     token(sc);
 236   }
 237
 238   if (sc->t == CTOK_WORD) {
 239     int i = conf_enum(sc, "fd,name,null", c ? ENUM_ABBREV : ENUM_NONE,
 240                       "file access type");
 241     type = i + 1;
 242     if (type && sc->t == ':')
 243       token(sc);
 244   }
 245
 246   /* --- Check for a valid file descriptor name --- */
 247
 248   if (sc->t == CTOK_WORD && type != FTYPE_NAME && type != FTYPE_NULL) {
 249     if (strcmp(sc->d.buf, "stdin") == 0) {
 250       fd = rstdin;
 251       REFFD_INC(rstdin);
 252     } else if (strcmp(sc->d.buf, "stdout") == 0) {
 253       fd = rstdout;
 254       REFFD_INC(rstdout);
 255     }
 256     if (fd)
 257       REFFD_INC(fd);
 258     else if (isdigit((unsigned char)*sc->d.buf)) {
 259       int nfd = atoi(sc->d.buf);
 260       switch (nfd) {
 261         case STDIN_FILENO: fd = rstdin; REFFD_INC(rstdin); break;
 262         case STDOUT_FILENO: fd = rstdout; REFFD_INC(rstdout); break;
 263         default:
 264           fd = reffd_init(nfd);
 265           fdflags(nfd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 266           break;
 267       }
 268     }
 269   }
 270
 271   /* --- Sort out what to do as a result --- */
 272
 273   if (type == FTYPE_NULL)
 274     f->type = FTYPE_NULL;
 275   else if (fd) {
 276     f->type = FTYPE_FD;
 277     f->u.fd = fd;
 278     token(sc);
 279   } else if (type == FTYPE_FD) {
 280     if (sc->t == CTOK_WORD)
 281       error(sc, "bad file descriptor `%s'", sc->d.buf);
 282     else
 283       error(sc, "parse error, expected file descriptor");
 284   } else {
 285     dstr d = DSTR_INIT;
 286     conf_name(sc, '/', &d);
 287     f->type = FTYPE_NAME;
 288     f->u.name = xstrdup(d.buf);
 289     dstr_destroy(&d);
 290   }
 291 }
 292
 293 /* --- @read@ --- */
 294
 295 static void file_read(fdata *f, scanner *sc)
 296 {
 297   file_fspec(&f->in, sc);
 298   if (sc->t != ',') {
 299     f->out = f->in;
 300     if (f->out.type == FTYPE_FD && f->out.u.fd == rstdin)
 301       f->out.u.fd = rstdout;
 302   } else {
 303     token(sc);
 304     file_fspec(&f->out, sc);
 305   }
 306   f->fa = fattr_global;
 307   f->fo = file_opts;
 308 }
 309
 310 /* --- @print@ --- */
 311
 312 static void file_pfspec(fspec *f, dstr *d)
 313 {
 314   switch (f->type) {
 315     case FTYPE_FD:
 316       switch (f->u.fd->fd) {
 317         case STDIN_FILENO:
 318           dstr_puts(d, "stdin");
 319           break;
 320         case STDOUT_FILENO:
 321           dstr_puts(d, "stdout");
 322           break;
 323         default:
 324           dstr_putf(d, "fd:%i", f->u.fd->fd);
 325           break;
 326       }
 327       break;
 328     case FTYPE_NAME:
 329       dstr_putf(d, "name:%s", f->u.name);
 330       break;
 331     case FTYPE_NULL:
 332       dstr_puts(d, "null");
 333       break;
 334   }
 335 }
 336
 337 static void file_desc(fdata *f, dstr *d)
 338 {
 339   dstr_puts(d, "file ");
 340   file_pfspec(&f->in, d);
 341   dstr_puts(d, ", ");
 342   file_pfspec(&f->out, d);
 343 }
 344
 345 /* --- @option@ --- */
 346
 347 static int file_option(fdata *f, scanner *sc)
 348 {
 349   fopts *fo = f ? &f->fo : &file_opts;
 350
 351   CONF_BEGIN(sc, "file", "file")
 352
 353   /* --- Handle file-specific options --- */
 354
 355   if (strcmp(sc->d.buf, "create") == 0) {
 356     token(sc);
 357     if (sc->t == '=')
 358       token(sc);
 359     switch (conf_enum(sc, "no,yes", ENUM_ABBREV, "create status")) {
 360       case 0: fo->of &= ~O_CREAT; break;
 361       case 1: fo->of |= O_CREAT; break;
 362     }
 363     CONF_ACCEPT;
 364   }
 365
 366   else if (strcmp(sc->d.buf, "open") == 0) {
 367     token(sc);
 368     if (sc->t == '=')
 369       token(sc);
 370     fo->of &= ~(O_TRUNC | O_APPEND | O_EXCL);
 371     switch (conf_enum(sc, "no,truncate,append",
 372                       ENUM_ABBREV, "open status")) {
 373       case 0: fo->of |= O_EXCL; break;
 374       case 1: fo->of |= O_TRUNC; break;
 375       case 2: fo->of |= O_APPEND; break;
 376     }
 377     CONF_ACCEPT;
 378   }
 379
 380   /* --- See if it's a file attribute --- */
 381
 382   {
 383     fattr *fa = f ? &f->fa : &fattr_global;
 384     if (fattr_option(sc, fa))
 385       CONF_ACCEPT;
 386   }
 387
 388   /* --- Nobody understood it --- */
 389
 390   CONF_END;
 391 }
 392
 393 /* --- @endpt@ --- */
 394
 395 static endpt *file_endpt(fdata *f, const char *desc)
 396 {
 397   reffd *in = 0, *out = 0;
 398   endpt *e;
 399
 400   /* --- Make the input file first --- */
 401
 402   switch (f->in.type) {
 403     case FTYPE_NULL:
 404       in = file_nullref();
 405       break;
 406     case FTYPE_FD:
 407       in = f->in.u.fd;
 408       REFFD_INC(in);
 409       break;
 410     case FTYPE_NAME: {
 411       int fd;
 412       if ((fd = open(f->in.u.name, O_RDONLY | O_NONBLOCK)) < 0) {
 413         fw_log(-1, "[%s] couldn't open `%s' for reading: %s",
 414                desc, f->in.u.name, strerror(errno));
 415         return (0);
 416       }
 417       in = reffd_init(fd);
 418     } break;
 419   }
 420
 421   /* --- Make the output file second --- */
 422
 423   switch (f->out.type) {
 424     case FTYPE_NULL:
 425       out = file_nullref();
 426       break;
 427     case FTYPE_FD:
 428       out = f->out.u.fd;
 429       REFFD_INC(out);
 430       break;
 431     case FTYPE_NAME: {
 432       int m = f->fo.of | O_WRONLY | O_NONBLOCK;
 433       int fd = -1;
 434
 435       /* --- First try creating the file --- *
 436        *
 437        * This lets me know whether to set the file attributes or not.  It
 438        * also stands a chance of noticing people playing silly beggars with
 439        * dangling symlinks.
 440        */
 441
 442       if ((m & O_CREAT) &&
 443           (fd = open(f->out.u.name, m | O_EXCL, f->fa.mode)) < 0 &&
 444           (errno != EEXIST || (m & O_EXCL))) {
 445         fw_log(-1, "[%s] couldn't create `%s': %s",
 446                desc, f->out.u.name, strerror(errno));
 447         REFFD_DEC(in);
 448         return (0);
 449       }
 450
 451       if (fd != -1) {
 452         if (fattr_apply(f->out.u.name, &f->fa)) {
 453           fw_log(-1, "[%s] couldn't apply file attributes to `%s': %s",
 454                  desc, f->out.u.name, strerror(errno));
 455         }
 456       } else if ((fd = open(f->out.u.name, m & ~O_CREAT)) < 0) {
 457         fw_log(-1, "[%s] couldn't open `%s': %s",
 458                desc, f->out.u.name, strerror(errno));
 459         REFFD_DEC(in);
 460         return (0);
 461       }
 462
 463       fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 464       out = reffd_init(fd);
 465     } break;
 466   }
 467
 468   /* --- Set up the endpoint --- */
 469
 470   e = CREATE(endpt);
 471   e->ops = &fept_ops;
 472   e->other = 0;
 473   e->f = EPF_FILE;
 474   e->t = 0;
 475   e->in = in;
 476   e->out = out;
 477   fw_inc();
 478   return (e);
 479 }
 480
 481 /* --- @destroy@ --- */
 482
 483 static void file_destroy(fdata *f)
 484 {
 485   if (f->in.type == FTYPE_NAME)
 486     xfree(f->in.u.name);
 487   if (f->out.type == FTYPE_NAME)
 488     xfree(f->out.u.name);
 489 }
 490
 491 /*----- File source description -------------------------------------------*/
 492
 493 /* --- @option@ --- */
 494
 495 static int fsource_option(source *s, scanner *sc)
 496 {
 497   fsource *fs = (fsource *)s;
 498   return (file_option(fs ? &fs->f : 0, sc));
 499 }
 500
 501 /* --- @read@ --- */
 502
 503 static source *fsource_read(scanner *sc)
 504 {
 505   fsource *fs;
 506
 507   if (!conf_prefix(sc, "file"))
 508     return (0);
 509   fs = CREATE(fsource);
 510   fs->s.ops = &fsource_ops;
 511   fs->s.desc = 0;
 512   file_read(&fs->f, sc);
 513   return (&fs->s);
 514 }
 515
 516 /* --- @attach@ --- */
 517
 518 static void fsource_destroy(source */*s*/);
 519
 520 static void fsource_attach(source *s, scanner *sc, target *t)
 521 {
 522   fsource *fs = (fsource *)s;
 523   endpt *e, *ee;
 524
 525   /* --- Set up the source description string --- */
 526
 527   {
 528     dstr d = DSTR_INIT;
 529     file_desc(&fs->f, &d);
 530     dstr_puts(&d, " -> ");
 531     dstr_puts(&d, t->desc);
 532     fs->s.desc = xstrdup(d.buf);
 533     dstr_destroy(&d);
 534   }
 535
 536   /* --- And then create the endpoints --- */
 537
 538   if ((ee = t->ops->create(t, fs->s.desc)) == 0)
 539     goto tidy;
 540   if ((e = file_endpt(&fs->f, fs->s.desc)) == 0) {
 541     ee->ops->close(ee);
 542     goto tidy;
 543   }
 544   endpt_join(e, ee);
 545
 546   /* --- Dispose of the source and target now --- */
 547
 548 tidy:
 549   t->ops->destroy(t);
 550   fsource_destroy(&fs->s);
 551 }
 552
 553 /* --- @destroy@ --- */
 554
 555 static void fsource_destroy(source *s)
 556 {
 557   fsource *fs = (fsource *)s;
 558   xfree(fs->s.desc);
 559   file_destroy(&fs->f);
 560   DESTROY(fs);
 561 }
 562
 563 /* --- File source operations --- */
 564
 565 source_ops fsource_ops = {
 566   "file",
 567   fsource_option, fsource_read, fsource_attach, fsource_destroy
 568 };
 569
 570 /*----- File target description -------------------------------------------*/
 571
 572 /* --- @option@ --- */
 573
 574 static int ftarget_option(target *t, scanner *sc)
 575 {
 576   ftarget *ft = (ftarget *)t;
 577   return (file_option(ft ? &ft->f : 0, sc));
 578 }
 579
 580 /* --- @read@ --- */
 581
 582 static target *ftarget_read(scanner *sc)
 583 {
 584   ftarget *ft;
 585   dstr d = DSTR_INIT;
 586
 587   if (!conf_prefix(sc, "file"))
 588     return (0);
 589   ft = CREATE(ftarget);
 590   ft->t.ops = &ftarget_ops;
 591   file_read(&ft->f, sc);
 592   file_desc(&ft->f, &d);
 593   ft->t.desc = xstrdup(d.buf);
 594   dstr_destroy(&d);
 595   return (&ft->t);
 596 }
 597
 598 /* --- @create@ --- */
 599
 600 static endpt *ftarget_create(target *t, const char *desc)
 601 {
 602   ftarget *ft = (ftarget *)t;
 603   endpt *e = file_endpt(&ft->f, desc);
 604   return (e);
 605 }
 606
 607 /* --- @destroy@ --- */
 608
 609 static void ftarget_destroy(target *t)
 610 {
 611   ftarget *ft = (ftarget *)t;
 612   file_destroy(&ft->f);
 613   xfree(ft->t.desc);
 614   DESTROY(ft);
 615 }
 616
 617 /* --- File target operations --- */
 618
 619 target_ops ftarget_ops = {
 620   "file",
 621   ftarget_option, ftarget_read, 0, ftarget_create, ftarget_destroy
 622 };
 623
 624 /*----- That's all, folks -------------------------------------------------*/