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 } 398