| 1 | /*- |
| 2 | * Copyright (c) 1991, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * This code is derived from software contributed to Berkeley by |
| 6 | * Kenneth Almquist. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. All advertising materials mentioning features or use of this software |
| 17 | * must display the following acknowledgement: |
| 18 | * This product includes software developed by the University of |
| 19 | * California, Berkeley and its contributors. |
| 20 | * 4. Neither the name of the University nor the names of its contributors |
| 21 | * may be used to endorse or promote products derived from this software |
| 22 | * without specific prior written permission. |
| 23 | * |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 34 | * SUCH DAMAGE. |
| 35 | * |
| 36 | * @(#)redir.c 8.2 (Berkeley) 5/4/95 |
| 37 | * $FreeBSD: src/bin/sh/redir.c,v 1.12.2.4 2002/08/27 01:36:28 tjr Exp $ |
| 38 | * $DragonFly: src/bin/sh/redir.c,v 1.3 2003/08/24 16:26:00 drhodus Exp $ |
| 39 | */ |
| 40 | |
| 41 | #include <sys/types.h> |
| 42 | #include <sys/stat.h> |
| 43 | #include <signal.h> |
| 44 | #include <string.h> |
| 45 | #include <fcntl.h> |
| 46 | #include <errno.h> |
| 47 | #include <unistd.h> |
| 48 | #include <stdlib.h> |
| 49 | |
| 50 | /* |
| 51 | * Code for dealing with input/output redirection. |
| 52 | */ |
| 53 | |
| 54 | #include "shell.h" |
| 55 | #include "nodes.h" |
| 56 | #include "jobs.h" |
| 57 | #include "expand.h" |
| 58 | #include "redir.h" |
| 59 | #include "output.h" |
| 60 | #include "memalloc.h" |
| 61 | #include "error.h" |
| 62 | #include "options.h" |
| 63 | |
| 64 | |
| 65 | #define EMPTY -2 /* marks an unused slot in redirtab */ |
| 66 | #define PIPESIZE 4096 /* amount of buffering in a pipe */ |
| 67 | |
| 68 | |
| 69 | MKINIT |
| 70 | struct redirtab { |
| 71 | struct redirtab *next; |
| 72 | int renamed[10]; |
| 73 | }; |
| 74 | |
| 75 | |
| 76 | MKINIT struct redirtab *redirlist; |
| 77 | |
| 78 | /* |
| 79 | * We keep track of whether or not fd0 has been redirected. This is for |
| 80 | * background commands, where we want to redirect fd0 to /dev/null only |
| 81 | * if it hasn't already been redirected. |
| 82 | */ |
| 83 | STATIC int fd0_redirected = 0; |
| 84 | |
| 85 | STATIC void openredirect(union node *, char[10 ]); |
| 86 | STATIC int openhere(union node *); |
| 87 | |
| 88 | |
| 89 | /* |
| 90 | * Process a list of redirection commands. If the REDIR_PUSH flag is set, |
| 91 | * old file descriptors are stashed away so that the redirection can be |
| 92 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the |
| 93 | * standard output, and the standard error if it becomes a duplicate of |
| 94 | * stdout, is saved in memory. |
| 95 | */ |
| 96 | |
| 97 | void |
| 98 | redirect(union node *redir, int flags) |
| 99 | { |
| 100 | union node *n; |
| 101 | struct redirtab *sv = NULL; |
| 102 | int i; |
| 103 | int fd; |
| 104 | int try; |
| 105 | char memory[10]; /* file descriptors to write to memory */ |
| 106 | |
| 107 | for (i = 10 ; --i >= 0 ; ) |
| 108 | memory[i] = 0; |
| 109 | memory[1] = flags & REDIR_BACKQ; |
| 110 | if (flags & REDIR_PUSH) { |
| 111 | sv = ckmalloc(sizeof (struct redirtab)); |
| 112 | for (i = 0 ; i < 10 ; i++) |
| 113 | sv->renamed[i] = EMPTY; |
| 114 | sv->next = redirlist; |
| 115 | redirlist = sv; |
| 116 | } |
| 117 | for (n = redir ; n ; n = n->nfile.next) { |
| 118 | fd = n->nfile.fd; |
| 119 | try = 0; |
| 120 | if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && |
| 121 | n->ndup.dupfd == fd) |
| 122 | continue; /* redirect from/to same file descriptor */ |
| 123 | |
| 124 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { |
| 125 | INTOFF; |
| 126 | again: |
| 127 | if ((i = fcntl(fd, F_DUPFD, 10)) == -1) { |
| 128 | switch (errno) { |
| 129 | case EBADF: |
| 130 | if (!try) { |
| 131 | openredirect(n, memory); |
| 132 | try++; |
| 133 | goto again; |
| 134 | } |
| 135 | /* FALLTHROUGH*/ |
| 136 | default: |
| 137 | INTON; |
| 138 | error("%d: %s", fd, strerror(errno)); |
| 139 | break; |
| 140 | } |
| 141 | } |
| 142 | if (!try) { |
| 143 | sv->renamed[fd] = i; |
| 144 | } |
| 145 | INTON; |
| 146 | } |
| 147 | if (fd == 0) |
| 148 | fd0_redirected++; |
| 149 | if (!try) |
| 150 | openredirect(n, memory); |
| 151 | } |
| 152 | if (memory[1]) |
| 153 | out1 = &memout; |
| 154 | if (memory[2]) |
| 155 | out2 = &memout; |
| 156 | } |
| 157 | |
| 158 | |
| 159 | STATIC void |
| 160 | openredirect(union node *redir, char memory[10]) |
| 161 | { |
| 162 | struct stat sb; |
| 163 | int fd = redir->nfile.fd; |
| 164 | char *fname; |
| 165 | int f; |
| 166 | |
| 167 | /* |
| 168 | * We suppress interrupts so that we won't leave open file |
| 169 | * descriptors around. This may not be such a good idea because |
| 170 | * an open of a device or a fifo can block indefinitely. |
| 171 | */ |
| 172 | INTOFF; |
| 173 | memory[fd] = 0; |
| 174 | switch (redir->nfile.type) { |
| 175 | case NFROM: |
| 176 | fname = redir->nfile.expfname; |
| 177 | if ((f = open(fname, O_RDONLY)) < 0) |
| 178 | error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); |
| 179 | movefd: |
| 180 | if (f != fd) { |
| 181 | close(fd); |
| 182 | copyfd(f, fd); |
| 183 | close(f); |
| 184 | } |
| 185 | break; |
| 186 | case NFROMTO: |
| 187 | fname = redir->nfile.expfname; |
| 188 | #ifdef O_CREAT |
| 189 | if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0) |
| 190 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 191 | #else |
| 192 | if ((f = open(fname, O_RDWR, 0666)) < 0) { |
| 193 | if (errno != ENOENT) |
| 194 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 195 | else if ((f = creat(fname, 0666)) < 0) |
| 196 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 197 | else { |
| 198 | close(f); |
| 199 | if ((f = open(fname, O_RDWR)) < 0) { |
| 200 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 201 | remove(fname); |
| 202 | } |
| 203 | } |
| 204 | } |
| 205 | #endif |
| 206 | goto movefd; |
| 207 | case NTO: |
| 208 | fname = redir->nfile.expfname; |
| 209 | if (Cflag && stat(fname, &sb) != -1 && S_ISREG(sb.st_mode)) |
| 210 | error("cannot create %s: %s", fname, |
| 211 | errmsg(EEXIST, E_CREAT)); |
| 212 | #ifdef O_CREAT |
| 213 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) |
| 214 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 215 | #else |
| 216 | if ((f = creat(fname, 0666)) < 0) |
| 217 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 218 | #endif |
| 219 | goto movefd; |
| 220 | case NCLOBBER: |
| 221 | fname = redir->nfile.expfname; |
| 222 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) |
| 223 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 224 | goto movefd; |
| 225 | case NAPPEND: |
| 226 | fname = redir->nfile.expfname; |
| 227 | #ifdef O_APPEND |
| 228 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) |
| 229 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 230 | #else |
| 231 | if ((f = open(fname, O_WRONLY)) < 0 |
| 232 | && (f = creat(fname, 0666)) < 0) |
| 233 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
| 234 | lseek(f, (off_t)0, 2); |
| 235 | #endif |
| 236 | goto movefd; |
| 237 | case NTOFD: |
| 238 | case NFROMFD: |
| 239 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ |
| 240 | if (memory[redir->ndup.dupfd]) |
| 241 | memory[fd] = 1; |
| 242 | else { |
| 243 | close(fd); |
| 244 | copyfd(redir->ndup.dupfd, fd); |
| 245 | } |
| 246 | } else |
| 247 | close(fd); |
| 248 | break; |
| 249 | case NHERE: |
| 250 | case NXHERE: |
| 251 | f = openhere(redir); |
| 252 | goto movefd; |
| 253 | default: |
| 254 | abort(); |
| 255 | } |
| 256 | INTON; |
| 257 | } |
| 258 | |
| 259 | |
| 260 | /* |
| 261 | * Handle here documents. Normally we fork off a process to write the |
| 262 | * data to a pipe. If the document is short, we can stuff the data in |
| 263 | * the pipe without forking. |
| 264 | */ |
| 265 | |
| 266 | STATIC int |
| 267 | openhere(union node *redir) |
| 268 | { |
| 269 | int pip[2]; |
| 270 | int len = 0; |
| 271 | |
| 272 | if (pipe(pip) < 0) |
| 273 | error("Pipe call failed: %s", strerror(errno)); |
| 274 | if (redir->type == NHERE) { |
| 275 | len = strlen(redir->nhere.doc->narg.text); |
| 276 | if (len <= PIPESIZE) { |
| 277 | xwrite(pip[1], redir->nhere.doc->narg.text, len); |
| 278 | goto out; |
| 279 | } |
| 280 | } |
| 281 | if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { |
| 282 | close(pip[0]); |
| 283 | signal(SIGINT, SIG_IGN); |
| 284 | signal(SIGQUIT, SIG_IGN); |
| 285 | signal(SIGHUP, SIG_IGN); |
| 286 | #ifdef SIGTSTP |
| 287 | signal(SIGTSTP, SIG_IGN); |
| 288 | #endif |
| 289 | signal(SIGPIPE, SIG_DFL); |
| 290 | if (redir->type == NHERE) |
| 291 | xwrite(pip[1], redir->nhere.doc->narg.text, len); |
| 292 | else |
| 293 | expandhere(redir->nhere.doc, pip[1]); |
| 294 | _exit(0); |
| 295 | } |
| 296 | out: |
| 297 | close(pip[1]); |
| 298 | return pip[0]; |
| 299 | } |
| 300 | |
| 301 | |
| 302 | |
| 303 | /* |
| 304 | * Undo the effects of the last redirection. |
| 305 | */ |
| 306 | |
| 307 | void |
| 308 | popredir(void) |
| 309 | { |
| 310 | struct redirtab *rp = redirlist; |
| 311 | int i; |
| 312 | |
| 313 | for (i = 0 ; i < 10 ; i++) { |
| 314 | if (rp->renamed[i] != EMPTY) { |
| 315 | if (i == 0) |
| 316 | fd0_redirected--; |
| 317 | close(i); |
| 318 | if (rp->renamed[i] >= 0) { |
| 319 | copyfd(rp->renamed[i], i); |
| 320 | close(rp->renamed[i]); |
| 321 | } |
| 322 | } |
| 323 | } |
| 324 | INTOFF; |
| 325 | redirlist = rp->next; |
| 326 | ckfree(rp); |
| 327 | INTON; |
| 328 | } |
| 329 | |
| 330 | /* |
| 331 | * Undo all redirections. Called on error or interrupt. |
| 332 | */ |
| 333 | |
| 334 | #ifdef mkinit |
| 335 | |
| 336 | INCLUDE "redir.h" |
| 337 | |
| 338 | RESET { |
| 339 | while (redirlist) |
| 340 | popredir(); |
| 341 | } |
| 342 | |
| 343 | SHELLPROC { |
| 344 | clearredir(); |
| 345 | } |
| 346 | |
| 347 | #endif |
| 348 | |
| 349 | /* Return true if fd 0 has already been redirected at least once. */ |
| 350 | int |
| 351 | fd0_redirected_p(void) |
| 352 | { |
| 353 | return fd0_redirected != 0; |
| 354 | } |
| 355 | |
| 356 | /* |
| 357 | * Discard all saved file descriptors. |
| 358 | */ |
| 359 | |
| 360 | void |
| 361 | clearredir(void) |
| 362 | { |
| 363 | struct redirtab *rp; |
| 364 | int i; |
| 365 | |
| 366 | for (rp = redirlist ; rp ; rp = rp->next) { |
| 367 | for (i = 0 ; i < 10 ; i++) { |
| 368 | if (rp->renamed[i] >= 0) { |
| 369 | close(rp->renamed[i]); |
| 370 | } |
| 371 | rp->renamed[i] = EMPTY; |
| 372 | } |
| 373 | } |
| 374 | } |
| 375 | |
| 376 | |
| 377 | |
| 378 | /* |
| 379 | * Copy a file descriptor to be >= to. Returns -1 |
| 380 | * if the source file descriptor is closed, EMPTY if there are no unused |
| 381 | * file descriptors left. |
| 382 | */ |
| 383 | |
| 384 | int |
| 385 | copyfd(int from, int to) |
| 386 | { |
| 387 | int newfd; |
| 388 | |
| 389 | newfd = fcntl(from, F_DUPFD, to); |
| 390 | if (newfd < 0) { |
| 391 | if (errno == EMFILE) |
| 392 | return EMPTY; |
| 393 | else |
| 394 | error("%d: %s", from, strerror(errno)); |
| 395 | } |
| 396 | return newfd; |
| 397 | } |