redir.c revision 1.47.2.2
1 /* $NetBSD: redir.c,v 1.47.2.2 2017/04/26 02:52:13 pgoyette Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #ifndef lint 37 #if 0 38 static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; 39 #else 40 __RCSID("$NetBSD: redir.c,v 1.47.2.2 2017/04/26 02:52:13 pgoyette Exp $"); 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/types.h> 45 #include <sys/param.h> /* PIPE_BUF */ 46 #include <sys/stat.h> 47 #include <signal.h> 48 #include <string.h> 49 #include <fcntl.h> 50 #include <errno.h> 51 #include <unistd.h> 52 #include <stdlib.h> 53 54 /* 55 * Code for dealing with input/output redirection. 56 */ 57 58 #include "main.h" 59 #include "builtins.h" 60 #include "shell.h" 61 #include "nodes.h" 62 #include "jobs.h" 63 #include "options.h" 64 #include "expand.h" 65 #include "redir.h" 66 #include "output.h" 67 #include "memalloc.h" 68 #include "mystring.h" 69 #include "error.h" 70 71 72 #define EMPTY -2 /* marks an unused slot in redirtab */ 73 #define CLOSED -1 /* fd was not open before redir */ 74 #ifndef PIPE_BUF 75 # define PIPESIZE 4096 /* amount of buffering in a pipe */ 76 #else 77 # define PIPESIZE PIPE_BUF 78 #endif 79 80 81 MKINIT 82 struct renamelist { 83 struct renamelist *next; 84 int orig; 85 int into; 86 }; 87 88 MKINIT 89 struct redirtab { 90 struct redirtab *next; 91 struct renamelist *renamed; 92 }; 93 94 95 MKINIT struct redirtab *redirlist; 96 97 /* 98 * We keep track of whether or not fd0 has been redirected. This is for 99 * background commands, where we want to redirect fd0 to /dev/null only 100 * if it hasn't already been redirected. 101 */ 102 STATIC int fd0_redirected = 0; 103 104 /* 105 * And also where to put internal use fds that should be out of the 106 * way of user defined fds (normally) 107 */ 108 STATIC int big_sh_fd = 0; 109 110 STATIC const struct renamelist *is_renamed(const struct renamelist *, int); 111 STATIC void fd_rename(struct redirtab *, int, int); 112 STATIC void free_rl(struct redirtab *, int); 113 STATIC void openredirect(union node *, char[10], int); 114 STATIC int openhere(const union node *); 115 STATIC int copyfd(int, int, int); 116 STATIC void find_big_fd(void); 117 118 STATIC const struct renamelist * 119 is_renamed(const struct renamelist *rl, int fd) 120 { 121 while (rl != NULL) { 122 if (rl->orig == fd) 123 return rl; 124 rl = rl->next; 125 } 126 return NULL; 127 } 128 129 STATIC void 130 free_rl(struct redirtab *rt, int reset) 131 { 132 struct renamelist *rl, *rn = rt->renamed; 133 134 while ((rl = rn) != NULL) { 135 rn = rl->next; 136 if (rl->orig == 0) 137 fd0_redirected--; 138 if (reset) { 139 if (rl->into < 0) 140 close(rl->orig); 141 else 142 movefd(rl->into, rl->orig); 143 } 144 ckfree(rl); 145 } 146 rt->renamed = NULL; 147 } 148 149 STATIC void 150 fd_rename(struct redirtab *rt, int from, int to) 151 { 152 struct renamelist *rl = ckmalloc(sizeof(struct renamelist)); 153 154 rl->next = rt->renamed; 155 rt->renamed = rl; 156 157 rl->orig = from; 158 rl->into = to; 159 } 160 161 /* 162 * Process a list of redirection commands. If the REDIR_PUSH flag is set, 163 * old file descriptors are stashed away so that the redirection can be 164 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the 165 * standard output, and the standard error if it becomes a duplicate of 166 * stdout, is saved in memory. 167 */ 168 169 void 170 redirect(union node *redir, int flags) 171 { 172 union node *n; 173 struct redirtab *sv = NULL; 174 int i; 175 int fd; 176 char memory[10]; /* file descriptors to write to memory */ 177 178 for (i = 10 ; --i >= 0 ; ) 179 memory[i] = 0; 180 memory[1] = flags & REDIR_BACKQ; 181 if (flags & REDIR_PUSH) { 182 /* We don't have to worry about REDIR_VFORK here, as 183 * flags & REDIR_PUSH is never true if REDIR_VFORK is set. 184 */ 185 sv = ckmalloc(sizeof (struct redirtab)); 186 sv->renamed = NULL; 187 sv->next = redirlist; 188 redirlist = sv; 189 } 190 for (n = redir ; n ; n = n->nfile.next) { 191 fd = n->nfile.fd; 192 if (fd > max_user_fd) 193 max_user_fd = fd; 194 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && 195 n->ndup.dupfd == fd) { 196 /* redirect from/to same file descriptor */ 197 /* make sure it stays open */ 198 if (fcntl(fd, F_SETFD, 0) < 0) 199 error("fd %d: %s", fd, strerror(errno)); 200 continue; 201 } 202 203 if ((flags & REDIR_PUSH) && !is_renamed(sv->renamed, fd)) { 204 INTOFF; 205 if (big_sh_fd < 10) 206 find_big_fd(); 207 if ((i = fcntl(fd, F_DUPFD, big_sh_fd)) == -1) { 208 switch (errno) { 209 case EBADF: 210 i = CLOSED; 211 break; 212 case EMFILE: 213 case EINVAL: 214 find_big_fd(); 215 i = fcntl(fd, F_DUPFD, big_sh_fd); 216 if (i >= 0) 217 break; 218 /* FALLTHRU */ 219 default: 220 i = errno; 221 INTON; /* XXX not needed here ? */ 222 error("%d: %s", fd, strerror(i)); 223 /* NOTREACHED */ 224 } 225 } 226 if (i >= 0) 227 (void)fcntl(i, F_SETFD, FD_CLOEXEC); 228 fd_rename(sv, fd, i); 229 INTON; 230 } 231 if (fd == 0) 232 fd0_redirected++; 233 openredirect(n, memory, flags); 234 } 235 if (memory[1]) 236 out1 = &memout; 237 if (memory[2]) 238 out2 = &memout; 239 } 240 241 242 STATIC void 243 openredirect(union node *redir, char memory[10], int flags) 244 { 245 struct stat sb; 246 int fd = redir->nfile.fd; 247 char *fname; 248 int f; 249 int eflags, cloexec; 250 251 /* 252 * We suppress interrupts so that we won't leave open file 253 * descriptors around. This may not be such a good idea because 254 * an open of a device or a fifo can block indefinitely. 255 */ 256 INTOFF; 257 if (fd < 10) 258 memory[fd] = 0; 259 switch (redir->nfile.type) { 260 case NFROM: 261 fname = redir->nfile.expfname; 262 if (flags & REDIR_VFORK) 263 eflags = O_NONBLOCK; 264 else 265 eflags = 0; 266 if ((f = open(fname, O_RDONLY|eflags)) < 0) 267 goto eopen; 268 if (eflags) 269 (void)fcntl(f, F_SETFL, fcntl(f, F_GETFL, 0) & ~eflags); 270 break; 271 case NFROMTO: 272 fname = redir->nfile.expfname; 273 if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0) 274 goto ecreate; 275 break; 276 case NTO: 277 if (Cflag) { 278 fname = redir->nfile.expfname; 279 if ((f = open(fname, O_WRONLY)) == -1) { 280 if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 281 0666)) < 0) 282 goto ecreate; 283 } else if (fstat(f, &sb) == -1) { 284 int serrno = errno; 285 close(f); 286 errno = serrno; 287 goto ecreate; 288 } else if (S_ISREG(sb.st_mode)) { 289 close(f); 290 errno = EEXIST; 291 goto ecreate; 292 } 293 break; 294 } 295 /* FALLTHROUGH */ 296 case NCLOBBER: 297 fname = redir->nfile.expfname; 298 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 299 goto ecreate; 300 break; 301 case NAPPEND: 302 fname = redir->nfile.expfname; 303 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 304 goto ecreate; 305 break; 306 case NTOFD: 307 case NFROMFD: 308 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 309 if (fd < 10 && redir->ndup.dupfd < 10 && 310 memory[redir->ndup.dupfd]) 311 memory[fd] = 1; 312 else if (copyfd(redir->ndup.dupfd, fd, 313 (flags & REDIR_KEEP) == 0) < 0) 314 error("Redirect (from %d to %d) failed: %s", 315 redir->ndup.dupfd, fd, strerror(errno)); 316 } else 317 (void) close(fd); 318 INTON; 319 return; 320 case NHERE: 321 case NXHERE: 322 f = openhere(redir); 323 break; 324 default: 325 abort(); 326 } 327 328 cloexec = fd > 2 && (flags & REDIR_KEEP) == 0; 329 if (f != fd) { 330 if (copyfd(f, fd, cloexec) < 0) { 331 int e = errno; 332 333 close(f); 334 error("redirect reassignment (fd %d) failed: %s", fd, 335 strerror(e)); 336 } 337 close(f); 338 } else if (cloexec) 339 (void)fcntl(f, F_SETFD, FD_CLOEXEC); 340 341 INTON; 342 return; 343 ecreate: 344 exerrno = 1; 345 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 346 eopen: 347 exerrno = 1; 348 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); 349 } 350 351 352 /* 353 * Handle here documents. Normally we fork off a process to write the 354 * data to a pipe. If the document is short, we can stuff the data in 355 * the pipe without forking. 356 */ 357 358 STATIC int 359 openhere(const union node *redir) 360 { 361 int pip[2]; 362 int len = 0; 363 364 if (pipe(pip) < 0) 365 error("Pipe call failed"); 366 if (redir->type == NHERE) { 367 len = strlen(redir->nhere.doc->narg.text); 368 if (len <= PIPESIZE) { 369 xwrite(pip[1], redir->nhere.doc->narg.text, len); 370 goto out; 371 } 372 } 373 if (forkshell(NULL, NULL, FORK_NOJOB) == 0) { 374 close(pip[0]); 375 signal(SIGINT, SIG_IGN); 376 signal(SIGQUIT, SIG_IGN); 377 signal(SIGHUP, SIG_IGN); 378 #ifdef SIGTSTP 379 signal(SIGTSTP, SIG_IGN); 380 #endif 381 signal(SIGPIPE, SIG_DFL); 382 if (redir->type == NHERE) 383 xwrite(pip[1], redir->nhere.doc->narg.text, len); 384 else 385 expandhere(redir->nhere.doc, pip[1]); 386 _exit(0); 387 } 388 out: 389 close(pip[1]); 390 return pip[0]; 391 } 392 393 394 395 /* 396 * Undo the effects of the last redirection. 397 */ 398 399 void 400 popredir(void) 401 { 402 struct redirtab *rp = redirlist; 403 404 INTOFF; 405 free_rl(rp, 1); 406 redirlist = rp->next; 407 ckfree(rp); 408 INTON; 409 } 410 411 /* 412 * Undo all redirections. Called on error or interrupt. 413 */ 414 415 #ifdef mkinit 416 417 INCLUDE "redir.h" 418 419 RESET { 420 while (redirlist) 421 popredir(); 422 } 423 424 SHELLPROC { 425 clearredir(0); 426 } 427 428 #endif 429 430 /* Return true if fd 0 has already been redirected at least once. */ 431 int 432 fd0_redirected_p(void) 433 { 434 return fd0_redirected != 0; 435 } 436 437 /* 438 * Discard all saved file descriptors. 439 */ 440 441 void 442 clearredir(int vforked) 443 { 444 struct redirtab *rp; 445 struct renamelist *rl; 446 447 for (rp = redirlist ; rp ; rp = rp->next) { 448 if (!vforked) 449 free_rl(rp, 0); 450 else for (rl = rp->renamed; rl; rl = rl->next) 451 if (rl->into >= 0) 452 close(rl->into); 453 } 454 } 455 456 457 458 /* 459 * Copy a file descriptor to be == to. 460 * cloexec indicates if we want close-on-exec or not. 461 * Returns -1 if any error occurs. 462 */ 463 464 STATIC int 465 copyfd(int from, int to, int cloexec) 466 { 467 int newfd; 468 469 if (cloexec && to > 2) 470 newfd = dup3(from, to, O_CLOEXEC); 471 else 472 newfd = dup2(from, to); 473 474 return newfd; 475 } 476 477 /* 478 * rename fd from to be fd to (closing from). 479 * close-on-exec is never set on 'to' (unless 480 * from==to and it was set on from) - ie: a no-op 481 * returns to (or errors() if an error occurs). 482 * 483 * This is mostly used for rearranging the 484 * results from pipe(). 485 */ 486 int 487 movefd(int from, int to) 488 { 489 if (from == to) 490 return to; 491 492 (void) close(to); 493 if (copyfd(from, to, 0) != to) { 494 int e = errno; 495 496 (void) close(from); 497 error("Unable to make fd %d: %s", to, strerror(e)); 498 } 499 (void) close(from); 500 501 return to; 502 } 503 504 STATIC void 505 find_big_fd(void) 506 { 507 int i, fd; 508 509 for (i = (1 << 10); i >= 10; i >>= 1) { 510 if ((fd = fcntl(0, F_DUPFD, i - 1)) >= 0) { 511 close(fd); 512 break; 513 } 514 } 515 516 fd = (i / 5) * 4; 517 if ((i - fd) > 100) 518 fd = i - 100; 519 else if (fd < 10) 520 fd = 10; 521 522 big_sh_fd = fd; 523 } 524 525 /* 526 * If possible, move file descriptor fd out of the way 527 * of expected user fd values. Returns the new fd 528 * (which may be the input fd if things do not go well.) 529 * Always set close-on-exec on the result, and close 530 * the input fd unless it is to be our result. 531 */ 532 int 533 to_upper_fd(int fd) 534 { 535 int i; 536 537 if (big_sh_fd < 10) 538 find_big_fd(); 539 do { 540 i = fcntl(fd, F_DUPFD_CLOEXEC, big_sh_fd); 541 if (i >= 0) { 542 if (fd != i) 543 close(fd); 544 return i; 545 } 546 if (errno != EMFILE) 547 break; 548 find_big_fd(); 549 } while (big_sh_fd > 10); 550 551 /* 552 * If we wanted to move this fd to some random high number 553 * we certainly do not intend to pass it through exec, even 554 * if the reassignment failed. 555 */ 556 (void)fcntl(fd, F_SETFD, FD_CLOEXEC); 557 return fd; 558 } 559 560 static const struct flgnames { 561 const char *name; 562 uint32_t value; 563 } nv[] = { 564 #ifdef O_APPEND 565 { "append", O_APPEND }, 566 #endif 567 #ifdef O_ASYNC 568 { "async", O_ASYNC }, 569 #endif 570 #ifdef O_SYNC 571 { "sync", O_SYNC }, 572 #endif 573 #ifdef O_NONBLOCK 574 { "nonblock", O_NONBLOCK }, 575 #endif 576 #ifdef O_FSYNC 577 { "fsync", O_FSYNC }, 578 #endif 579 #ifdef O_DSYNC 580 { "dsync", O_DSYNC }, 581 #endif 582 #ifdef O_RSYNC 583 { "rsync", O_RSYNC }, 584 #endif 585 #ifdef O_ALTIO 586 { "altio", O_ALT_IO }, 587 #endif 588 #ifdef O_DIRECT 589 { "direct", O_DIRECT }, 590 #endif 591 #ifdef O_NOSIGPIPE 592 { "nosigpipe", O_NOSIGPIPE }, 593 #endif 594 #ifdef O_CLOEXEC 595 { "cloexec", O_CLOEXEC }, 596 #endif 597 { 0, 0 } 598 }; 599 #define ALLFLAGS (O_APPEND|O_ASYNC|O_SYNC|O_NONBLOCK|O_DSYNC|O_RSYNC|\ 600 O_ALT_IO|O_DIRECT|O_NOSIGPIPE|O_CLOEXEC) 601 602 static int 603 getflags(int fd, int p) 604 { 605 int c, f; 606 607 if ((c = fcntl(fd, F_GETFD)) == -1) { 608 if (!p) 609 return -1; 610 error("Can't get status for fd=%d (%s)", fd, strerror(errno)); 611 } 612 if ((f = fcntl(fd, F_GETFL)) == -1) { 613 if (!p) 614 return -1; 615 error("Can't get flags for fd=%d (%s)", fd, strerror(errno)); 616 } 617 if (c & FD_CLOEXEC) 618 f |= O_CLOEXEC; 619 return f & ALLFLAGS; 620 } 621 622 static void 623 printone(int fd, int p, int verbose, int pfd) 624 { 625 int f = getflags(fd, p); 626 const struct flgnames *fn; 627 628 if (f == -1) 629 return; 630 631 if (pfd) 632 outfmt(out1, "%d: ", fd); 633 for (fn = nv; fn->name; fn++) { 634 if (f & fn->value) { 635 outfmt(out1, "%s%s", verbose ? "+" : "", fn->name); 636 f &= ~fn->value; 637 } else if (verbose) 638 outfmt(out1, "-%s", fn->name); 639 else 640 continue; 641 if (f || (verbose && fn[1].name)) 642 outfmt(out1, ","); 643 } 644 if (verbose && f) /* f should be normally be 0 */ 645 outfmt(out1, " +%#x", f); 646 outfmt(out1, "\n"); 647 } 648 649 static void 650 parseflags(char *s, int *p, int *n) 651 { 652 int *v, *w; 653 const struct flgnames *fn; 654 655 *p = 0; 656 *n = 0; 657 for (s = strtok(s, ","); s; s = strtok(NULL, ",")) { 658 switch (*s++) { 659 case '+': 660 v = p; 661 w = n; 662 break; 663 case '-': 664 v = n; 665 w = p; 666 break; 667 default: 668 error("Missing +/- indicator before flag %s", s-1); 669 } 670 671 for (fn = nv; fn->name; fn++) 672 if (strcmp(s, fn->name) == 0) { 673 *v |= fn->value; 674 *w &=~ fn->value; 675 break; 676 } 677 if (fn->name == 0) 678 error("Bad flag `%s'", s); 679 } 680 } 681 682 static void 683 setone(int fd, int pos, int neg, int verbose) 684 { 685 int f = getflags(fd, 1); 686 int n, cloexec; 687 688 if (f == -1) 689 return; 690 691 cloexec = -1; 692 if ((pos & O_CLOEXEC) && !(f & O_CLOEXEC)) 693 cloexec = FD_CLOEXEC; 694 if ((neg & O_CLOEXEC) && (f & O_CLOEXEC)) 695 cloexec = 0; 696 697 if (cloexec != -1 && fcntl(fd, F_SETFD, cloexec) == -1) 698 error("Can't set status for fd=%d (%s)", fd, strerror(errno)); 699 700 pos &= ~O_CLOEXEC; 701 neg &= ~O_CLOEXEC; 702 f &= ~O_CLOEXEC; 703 n = f; 704 n |= pos; 705 n &= ~neg; 706 if (n != f && fcntl(fd, F_SETFL, n) == -1) 707 error("Can't set flags for fd=%d (%s)", fd, strerror(errno)); 708 if (verbose) 709 printone(fd, 1, verbose, 1); 710 } 711 712 int 713 fdflagscmd(int argc, char *argv[]) 714 { 715 char *num; 716 int verbose = 0, ch, pos = 0, neg = 0; 717 char *setflags = NULL; 718 719 optreset = 1; optind = 1; /* initialize getopt */ 720 while ((ch = getopt(argc, argv, ":vs:")) != -1) 721 switch ((char)ch) { 722 case 'v': 723 verbose = 1; 724 break; 725 case 's': 726 if (setflags) 727 goto msg; 728 setflags = optarg; 729 break; 730 case '?': 731 default: 732 msg: 733 error("Usage: fdflags [-v] [-s <flags> fd] [fd...]"); 734 /* NOTREACHED */ 735 } 736 737 argc -= optind, argv += optind; 738 739 if (setflags) 740 parseflags(setflags, &pos, &neg); 741 742 if (argc == 0) { 743 int i; 744 745 if (setflags) 746 goto msg; 747 748 /* 749 * XXX we should only ever operate on user defined fds 750 * XXX not on sh internal fds that might be open. 751 * XXX but for that we need to know their range (later) 752 */ 753 for (i = 0; i <= max_user_fd; i++) 754 printone(i, 0, verbose, 1); 755 return 0; 756 } 757 758 while ((num = *argv++) != NULL) { 759 int fd = number(num); 760 761 while (num[0] == '0' && num[1] != '\0') /* skip 0's */ 762 num++; 763 if (strlen(num) > 5) 764 error("%s too big to be a file descriptor", num); 765 766 if (setflags) 767 setone(fd, pos, neg, verbose); 768 else 769 printone(fd, 1, verbose, argc > 1); 770 } 771 return 0; 772 } 773
Indexes created Thu Oct 23 22:10:10 GMT 2025