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 close(fd); 149 } 150 INTON; 151 } else { 152 close(fd); 153 } 154 if (fd == 0) 155 fd0_redirected++; 156 if (!try) 157 openredirect(n, memory); 158 } 159 if (memory[1]) 160 out1 = &memout; 161 if (memory[2]) 162 out2 = &memout; 163 } 164 165 166 STATIC void 167 openredirect(redir, memory) 168 union node *redir; 169 char memory[10]; 170 { 171 int fd = redir->nfile.fd; 172 char *fname; 173 int f; 174 175 /* 176 * We suppress interrupts so that we won't leave open file 177 * descriptors around. This may not be such a good idea because 178 * an open of a device or a fifo can block indefinitely. 179 */ 180 INTOFF; 181 memory[fd] = 0; 182 switch (redir->nfile.type) { 183 case NFROM: 184 fname = redir->nfile.expfname; 185 if ((f = open(fname, O_RDONLY)) < 0) 186 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); 187 movefd: 188 if (f != fd) { 189 copyfd(f, fd); 190 close(f); 191 } 192 break; 193 case NTO: 194 fname = redir->nfile.expfname; 195 #ifdef O_CREAT 196 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 197 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 198 #else 199 if ((f = creat(fname, 0666)) < 0) 200 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 201 #endif 202 goto movefd; 203 case NAPPEND: 204 fname = redir->nfile.expfname; 205 #ifdef O_APPEND 206 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 207 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 208 #else 209 if ((f = open(fname, O_WRONLY)) < 0 210 && (f = creat(fname, 0666)) < 0) 211 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 212 lseek(f, (off_t)0, 2); 213 #endif 214 goto movefd; 215 case NTOFD: 216 case NFROMFD: 217 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 218 if (memory[redir->ndup.dupfd]) 219 memory[fd] = 1; 220 else 221 copyfd(redir->ndup.dupfd, fd); 222 } 223 break; 224 case NHERE: 225 case NXHERE: 226 f = openhere(redir); 227 goto movefd; 228 default: 229 abort(); 230 } 231 INTON; 232 } 233 234 235 /* 236 * Handle here documents. Normally we fork off a process to write the 237 * data to a pipe. If the document is short, we can stuff the data in 238 * the pipe without forking. 239 */ 240 241 STATIC int 242 openhere(redir) 243 union node *redir; 244 { 245 int pip[2]; 246 int len = 0; 247 248 if (pipe(pip) < 0) 249 error("Pipe call failed: %s", strerror(errno)); 250 if (redir->type == NHERE) { 251 len = strlen(redir->nhere.doc->narg.text); 252 if (len <= PIPESIZE) { 253 xwrite(pip[1], redir->nhere.doc->narg.text, len); 254 goto out; 255 } 256 } 257 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 258 close(pip[0]); 259 signal(SIGINT, SIG_IGN); 260 signal(SIGQUIT, SIG_IGN); 261 signal(SIGHUP, SIG_IGN); 262 #ifdef SIGTSTP 263 signal(SIGTSTP, SIG_IGN); 264 #endif 265 signal(SIGPIPE, SIG_DFL); 266 if (redir->type == NHERE) 267 xwrite(pip[1], redir->nhere.doc->narg.text, len); 268 else 269 expandhere(redir->nhere.doc, pip[1]); 270 _exit(0); 271 } 272 out: 273 close(pip[1]); 274 return pip[0]; 275 } 276 277 278 279 /* 280 * Undo the effects of the last redirection. 281 */ 282 283 void 284 popredir() { 285 struct redirtab *rp = redirlist; 286 int i; 287 288 for (i = 0 ; i < 10 ; i++) { 289 if (rp->renamed[i] != EMPTY) { 290 if (i == 0) 291 fd0_redirected--; 292 close(i); 293 if (rp->renamed[i] >= 0) { 294 copyfd(rp->renamed[i], i); 295 close(rp->renamed[i]); 296 } 297 } 298 } 299 INTOFF; 300 redirlist = rp->next; 301 ckfree(rp); 302 INTON; 303 } 304 305 /* 306 * Undo all redirections. Called on error or interrupt. 307 */ 308 309 #ifdef mkinit 310 311 INCLUDE "redir.h" 312 313 RESET { 314 while (redirlist) 315 popredir(); 316 } 317 318 SHELLPROC { 319 clearredir(); 320 } 321 322 #endif 323 324 /* Return true if fd 0 has already been redirected at least once. */ 325 int 326 fd0_redirected_p () { 327 return fd0_redirected != 0; 328 } 329 330 /* 331 * Discard all saved file descriptors. 332 */ 333 334 void 335 clearredir() { 336 struct redirtab *rp; 337 int i; 338 339 for (rp = redirlist ; rp ; rp = rp->next) { 340 for (i = 0 ; i < 10 ; i++) { 341 if (rp->renamed[i] >= 0) { 342 close(rp->renamed[i]); 343 } 344 rp->renamed[i] = EMPTY; 345 } 346 } 347 } 348 349 350 351 /* 352 * Copy a file descriptor to be >= to. Returns -1 353 * if the source file descriptor is closed, EMPTY if there are no unused 354 * file descriptors left. 355 */ 356 357 int 358 copyfd(from, to) 359 int from; 360 int to; 361 { 362 int newfd; 363 364 newfd = fcntl(from, F_DUPFD, to); 365 if (newfd < 0) { 366 if (errno == EMFILE) 367 return EMPTY; 368 else 369 error("%d: %s", from, strerror(errno)); 370 } 371 return newfd; 372 } 373