1 /* $NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos 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 1.29 2004/07/08 03:57:33 christos Exp $"); 41 #endif 42 #endif /* not lint */ 43 44 #include <sys/types.h> 45 #include <sys/param.h> /* PIPE_BUF */ 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 "main.h" 58 #include "shell.h" 59 #include "nodes.h" 60 #include "jobs.h" 61 #include "options.h" 62 #include "expand.h" 63 #include "redir.h" 64 #include "output.h" 65 #include "memalloc.h" 66 #include "error.h" 67 68 69 #define EMPTY -2 /* marks an unused slot in redirtab */ 70 #ifndef PIPE_BUF 71 # define PIPESIZE 4096 /* amount of buffering in a pipe */ 72 #else 73 # define PIPESIZE PIPE_BUF 74 #endif 75 76 #define signal bsd_signal 77 78 MKINIT 79 struct redirtab { 80 struct redirtab *next; 81 short renamed[10]; 82 }; 83 84 85 MKINIT struct redirtab *redirlist; 86 87 /* 88 * We keep track of whether or not fd0 has been redirected. This is for 89 * background commands, where we want to redirect fd0 to /dev/null only 90 * if it hasn't already been redirected. 91 */ 92 int fd0_redirected = 0; 93 94 STATIC void openredirect(union node *, char[10], int); 95 STATIC int openhere(union node *); 96 97 98 /* 99 * Process a list of redirection commands. If the REDIR_PUSH flag is set, 100 * old file descriptors are stashed away so that the redirection can be 101 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the 102 * standard output, and the standard error if it becomes a duplicate of 103 * stdout, is saved in memory. 104 */ 105 106 void 107 redirect(union node *redir, int flags) 108 { 109 union node *n; 110 struct redirtab *sv = NULL; 111 int i; 112 int fd; 113 int try; 114 char memory[10]; /* file descriptors to write to memory */ 115 116 for (i = 10 ; --i >= 0 ; ) 117 memory[i] = 0; 118 memory[1] = flags & REDIR_BACKQ; 119 if (flags & REDIR_PUSH) { 120 /* We don't have to worry about REDIR_VFORK here, as 121 * flags & REDIR_PUSH is never true if REDIR_VFORK is set. 122 */ 123 sv = ckmalloc(sizeof (struct redirtab)); 124 for (i = 0 ; i < 10 ; i++) 125 sv->renamed[i] = EMPTY; 126 sv->next = redirlist; 127 redirlist = sv; 128 } 129 for (n = redir ; n ; n = n->nfile.next) { 130 fd = n->nfile.fd; 131 try = 0; 132 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && 133 n->ndup.dupfd == fd) 134 continue; /* redirect from/to same file descriptor */ 135 136 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { 137 INTOFF; 138 again: 139 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) { 140 switch (errno) { 141 case EBADF: 142 if (!try) { 143 openredirect(n, memory, flags); 144 try++; 145 goto again; 146 } 147 /* FALLTHROUGH*/ 148 default: 149 INTON; 150 error("%d: %s", fd, strerror(errno)); 151 /* NOTREACHED */ 152 } 153 } 154 if (!try) { 155 sv->renamed[fd] = i; 156 close(fd); 157 } 158 INTON; 159 } else { 160 close(fd); 161 } 162 if (fd == 0) 163 fd0_redirected++; 164 if (!try) 165 openredirect(n, memory, flags); 166 } 167 if (memory[1]) 168 out1 = &memout; 169 if (memory[2]) 170 out2 = &memout; 171 } 172 173 174 STATIC void 175 openredirect(union node *redir, char memory[10], int flags) 176 { 177 int fd = redir->nfile.fd; 178 char *fname; 179 int f; 180 int oflags = O_WRONLY|O_CREAT|O_TRUNC, eflags; 181 182 /* 183 * We suppress interrupts so that we won't leave open file 184 * descriptors around. This may not be such a good idea because 185 * an open of a device or a fifo can block indefinitely. 186 */ 187 INTOFF; 188 memory[fd] = 0; 189 switch (redir->nfile.type) { 190 case NFROM: 191 fname = redir->nfile.expfname; 192 if (flags & REDIR_VFORK) 193 eflags = O_NONBLOCK; 194 else 195 eflags = 0; 196 if ((f = open(fname, O_RDONLY|eflags)) < 0) 197 goto eopen; 198 if (eflags) 199 (void)fcntl(f, F_SETFL, fcntl(f, F_GETFL, 0) & ~eflags); 200 break; 201 case NFROMTO: 202 fname = redir->nfile.expfname; 203 if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0) 204 goto ecreate; 205 break; 206 case NTO: 207 if (Cflag) 208 oflags |= O_EXCL; 209 /* FALLTHROUGH */ 210 case NCLOBBER: 211 fname = redir->nfile.expfname; 212 if ((f = open(fname, oflags, 0666)) < 0) 213 goto ecreate; 214 break; 215 case NAPPEND: 216 fname = redir->nfile.expfname; 217 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 218 goto ecreate; 219 break; 220 case NTOFD: 221 case NFROMFD: 222 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 223 if (memory[redir->ndup.dupfd]) 224 memory[fd] = 1; 225 else 226 copyfd(redir->ndup.dupfd, fd); 227 } 228 INTON; 229 return; 230 case NHERE: 231 case NXHERE: 232 f = openhere(redir); 233 break; 234 default: 235 abort(); 236 } 237 238 if (f != fd) { 239 copyfd(f, fd); 240 close(f); 241 } 242 INTON; 243 return; 244 ecreate: 245 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 246 eopen: 247 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); 248 } 249 250 251 /* 252 * Handle here documents. Normally we fork off a process to write the 253 * data to a pipe. If the document is short, we can stuff the data in 254 * the pipe without forking. 255 */ 256 257 STATIC int 258 openhere(union node *redir) 259 { 260 int pip[2]; 261 int len = 0; 262 263 if (pipe(pip) < 0) 264 error("Pipe call failed"); 265 if (redir->type == NHERE) { 266 len = strlen(redir->nhere.doc->narg.text); 267 if (len <= PIPESIZE) { 268 xwrite(pip[1], redir->nhere.doc->narg.text, len); 269 goto out; 270 } 271 } 272 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 273 close(pip[0]); 274 signal(SIGINT, SIG_IGN); 275 signal(SIGQUIT, SIG_IGN); 276 signal(SIGHUP, SIG_IGN); 277 #ifdef SIGTSTP 278 signal(SIGTSTP, SIG_IGN); 279 #endif 280 signal(SIGPIPE, SIG_DFL); 281 if (redir->type == NHERE) 282 xwrite(pip[1], redir->nhere.doc->narg.text, len); 283 else 284 expandhere(redir->nhere.doc, pip[1]); 285 _exit(0); 286 } 287 out: 288 close(pip[1]); 289 return pip[0]; 290 } 291 292 293 294 /* 295 * Undo the effects of the last redirection. 296 */ 297 298 void 299 popredir(void) 300 { 301 struct redirtab *rp = redirlist; 302 int i; 303 304 for (i = 0 ; i < 10 ; i++) { 305 if (rp->renamed[i] != EMPTY) { 306 if (i == 0) 307 fd0_redirected--; 308 close(i); 309 if (rp->renamed[i] >= 0) { 310 copyfd(rp->renamed[i], i); 311 close(rp->renamed[i]); 312 } 313 } 314 } 315 INTOFF; 316 redirlist = rp->next; 317 ckfree(rp); 318 INTON; 319 } 320 321 /* 322 * Undo all redirections. Called on error or interrupt. 323 */ 324 325 #ifdef mkinit 326 327 INCLUDE "redir.h" 328 329 RESET { 330 while (redirlist) 331 popredir(); 332 } 333 334 SHELLPROC { 335 clearredir(0); 336 } 337 338 #endif 339 340 /* Return true if fd 0 has already been redirected at least once. */ 341 int 342 fd0_redirected_p () { 343 return fd0_redirected != 0; 344 } 345 346 /* 347 * Discard all saved file descriptors. 348 */ 349 350 void 351 clearredir(vforked) 352 int vforked; 353 { 354 struct redirtab *rp; 355 int i; 356 357 for (rp = redirlist ; rp ; rp = rp->next) { 358 for (i = 0 ; i < 10 ; i++) { 359 if (rp->renamed[i] >= 0) { 360 close(rp->renamed[i]); 361 } 362 if (!vforked) 363 rp->renamed[i] = EMPTY; 364 } 365 } 366 } 367 368 369 370 /* 371 * Copy a file descriptor to be >= to. Returns -1 372 * if the source file descriptor is closed, EMPTY if there are no unused 373 * file descriptors left. 374 */ 375 376 int 377 copyfd(int from, int to) 378 { 379 int newfd; 380 381 newfd = fcntl(from, F_DUPFD, to); 382 if (newfd < 0) { 383 if (errno == EMFILE) 384 return EMPTY; 385 else 386 error("%d: %s", from, strerror(errno)); 387 } 388 return newfd; 389 } 390
