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 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* not lint */ 44 45 #include <sys/types.h> 46 #include <signal.h> 47 #include <string.h> 48 #include <fcntl.h> 49 #include <errno.h> 50 #include <unistd.h> 51 #include <stdlib.h> 52 53 /* 54 * Code for dealing with input/output redirection. 55 */ 56 57 #include "shell.h" 58 #include "nodes.h" 59 #include "jobs.h" 60 #include "expand.h" 61 #include "redir.h" 62 #include "output.h" 63 #include "memalloc.h" 64 #include "error.h" 65 66 67 #define EMPTY -2 /* marks an unused slot in redirtab */ 68 #define PIPESIZE 4096 /* amount of buffering in a pipe */ 69 70 71 MKINIT 72 struct redirtab { 73 struct redirtab *next; 74 short renamed[10]; 75 }; 76 77 78 MKINIT struct redirtab *redirlist; 79 80 /* 81 * We keep track of whether or not fd0 has been redirected. This is for 82 * background commands, where we want to redirect fd0 to /dev/null only 83 * if it hasn't already been redirected. 84 */ 85 int fd0_redirected = 0; 86 87 STATIC void openredirect __P((union node *, char[10 ])); 88 STATIC int openhere __P((union node *)); 89 90 91 /* 92 * Process a list of redirection commands. If the REDIR_PUSH flag is set, 93 * old file descriptors are stashed away so that the redirection can be 94 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the 95 * standard output, and the standard error if it becomes a duplicate of 96 * stdout, is saved in memory. 97 */ 98 99 void 100 redirect(redir, flags) 101 union node *redir; 102 int flags; 103 { 104 union node *n; 105 struct redirtab *sv = NULL; 106 int i; 107 int fd; 108 int try; 109 char memory[10]; /* file descriptors to write to memory */ 110 111 for (i = 10 ; --i >= 0 ; ) 112 memory[i] = 0; 113 memory[1] = flags & REDIR_BACKQ; 114 if (flags & REDIR_PUSH) { 115 sv = ckmalloc(sizeof (struct redirtab)); 116 for (i = 0 ; i < 10 ; i++) 117 sv->renamed[i] = EMPTY; 118 sv->next = redirlist; 119 redirlist = sv; 120 } 121 for (n = redir ; n ; n = n->nfile.next) { 122 fd = n->nfile.fd; 123 try = 0; 124 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && 125 n->ndup.dupfd == fd) 126 continue; /* redirect from/to same file descriptor */ 127 128 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { 129 INTOFF; 130 again: 131 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) { 132 switch (errno) { 133 case EBADF: 134 if (!try) { 135 openredirect(n, memory); 136 try++; 137 goto again; 138 } 139 /* FALLTHROUGH*/ 140 default: 141 INTON; 142 error("%d: %s", fd, strerror(errno)); 143 break; 144 } 145 } 146 if (!try) { 147 sv->renamed[fd] = i; 148 } 149 INTON; 150 } 151 if (fd == 0) 152 fd0_redirected++; 153 if (!try) 154 openredirect(n, memory); 155 } 156 if (memory[1]) 157 out1 = &memout; 158 if (memory[2]) 159 out2 = &memout; 160 } 161 162 163 STATIC void 164 openredirect(redir, memory) 165 union node *redir; 166 char memory[10]; 167 { 168 int fd = redir->nfile.fd; 169 char *fname; 170 int f; 171 172 /* 173 * We suppress interrupts so that we won't leave open file 174 * descriptors around. This may not be such a good idea because 175 * an open of a device or a fifo can block indefinitely. 176 */ 177 INTOFF; 178 memory[fd] = 0; 179 switch (redir->nfile.type) { 180 case NFROM: 181 fname = redir->nfile.expfname; 182 if ((f = open(fname, O_RDONLY)) < 0) 183 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); 184 movefd: 185 if (f != fd) { 186 close(fd); 187 copyfd(f, fd); 188 close(f); 189 } 190 break; 191 case NFROMTO: 192 fname = redir->nfile.expfname; 193 #ifdef O_CREAT 194 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0) 195 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 196 #else 197 if ((f = open(fname, O_RDWR, 0666)) < 0) { 198 if (errno != ENOENT) 199 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 200 else if ((f = creat(fname, 0666)) < 0) 201 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 202 else { 203 close(f); 204 if ((f = open(fname, O_RDWR)) < 0) { 205 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 206 remove(fname); 207 } 208 } 209 } 210 #endif 211 goto movefd; 212 case NTO: 213 fname = redir->nfile.expfname; 214 #ifdef O_CREAT 215 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 216 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 217 #else 218 if ((f = creat(fname, 0666)) < 0) 219 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 220 #endif 221 goto movefd; 222 case NAPPEND: 223 fname = redir->nfile.expfname; 224 #ifdef O_APPEND 225 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 226 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 227 #else 228 if ((f = open(fname, O_WRONLY)) < 0 229 && (f = creat(fname, 0666)) < 0) 230 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 231 lseek(f, (off_t)0, 2); 232 #endif 233 goto movefd; 234 case NTOFD: 235 case NFROMFD: 236 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 237 if (memory[redir->ndup.dupfd]) 238 memory[fd] = 1; 239 else { 240 close(fd); 241 copyfd(redir->ndup.dupfd, fd); 242 } 243 } 244 break; 245 case NHERE: 246 case NXHERE: 247 f = openhere(redir); 248 goto movefd; 249 default: 250 abort(); 251 } 252 INTON; 253 } 254 255 256 /* 257 * Handle here documents. Normally we fork off a process to write the 258 * data to a pipe. If the document is short, we can stuff the data in 259 * the pipe without forking. 260 */ 261 262 STATIC int 263 openhere(redir) 264 union node *redir; 265 { 266 int pip[2]; 267 int len = 0; 268 269 if (pipe(pip) < 0) 270 error("Pipe call failed: %s", strerror(errno)); 271 if (redir->type == NHERE) { 272 len = strlen(redir->nhere.doc->narg.text); 273 if (len <= PIPESIZE) { 274 xwrite(pip[1], redir->nhere.doc->narg.text, len); 275 goto out; 276 } 277 } 278 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 279 close(pip[0]); 280 signal(SIGINT, SIG_IGN); 281 signal(SIGQUIT, SIG_IGN); 282 signal(SIGHUP, SIG_IGN); 283 #ifdef SIGTSTP 284 signal(SIGTSTP, SIG_IGN); 285 #endif 286 signal(SIGPIPE, SIG_DFL); 287 if (redir->type == NHERE) 288 xwrite(pip[1], redir->nhere.doc->narg.text, len); 289 else 290 expandhere(redir->nhere.doc, pip[1]); 291 _exit(0); 292 } 293 out: 294 close(pip[1]); 295 return pip[0]; 296 } 297 298 299 300 /* 301 * Undo the effects of the last redirection. 302 */ 303 304 void 305 popredir() { 306 struct redirtab *rp = redirlist; 307 int i; 308 309 for (i = 0 ; i < 10 ; i++) { 310 if (rp->renamed[i] != EMPTY) { 311 if (i == 0) 312 fd0_redirected--; 313 close(i); 314 if (rp->renamed[i] >= 0) { 315 copyfd(rp->renamed[i], i); 316 close(rp->renamed[i]); 317 } 318 } 319 } 320 INTOFF; 321 redirlist = rp->next; 322 ckfree(rp); 323 INTON; 324 } 325 326 /* 327 * Undo all redirections. Called on error or interrupt. 328 */ 329 330 #ifdef mkinit 331 332 INCLUDE "redir.h" 333 334 RESET { 335 while (redirlist) 336 popredir(); 337 } 338 339 SHELLPROC { 340 clearredir(); 341 } 342 343 #endif 344 345 /* Return true if fd 0 has already been redirected at least once. */ 346 int 347 fd0_redirected_p () { 348 return fd0_redirected != 0; 349 } 350 351 /* 352 * Discard all saved file descriptors. 353 */ 354 355 void 356 clearredir() { 357 struct redirtab *rp; 358 int i; 359 360 for (rp = redirlist ; rp ; rp = rp->next) { 361 for (i = 0 ; i < 10 ; i++) { 362 if (rp->renamed[i] >= 0) { 363 close(rp->renamed[i]); 364 } 365 rp->renamed[i] = EMPTY; 366 } 367 } 368 } 369 370 371 372 /* 373 * Copy a file descriptor to be >= to. Returns -1 374 * if the source file descriptor is closed, EMPTY if there are no unused 375 * file descriptors left. 376 */ 377 378 int 379 copyfd(from, to) 380 int from; 381 int to; 382 { 383 int newfd; 384 385 newfd = fcntl(from, F_DUPFD, to); 386 if (newfd < 0) { 387 if (errno == EMFILE) 388 return EMPTY; 389 else 390 error("%d: %s", from, strerror(errno)); 391 } 392 return newfd; 393 } 394