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 /*static char sccsid[] = "from: @(#)redir.c 8.1 (Berkeley) 5/31/93";*/ 39 static char *rcsid = "$Id: redir.c,v 1.9 1994/12/05 19:07:52 cgd Exp $"; 40 #endif /* not lint */ 41 42 /* 43 * Code for dealing with input/output redirection. 44 */ 45 46 #include "shell.h" 47 #include "nodes.h" 48 #include "jobs.h" 49 #include "expand.h" 50 #include "redir.h" 51 #include "output.h" 52 #include "memalloc.h" 53 #include "error.h" 54 #include <sys/types.h> 55 #include <signal.h> 56 #include <fcntl.h> 57 #include <errno.h> 58 #include <unistd.h> 59 60 61 #define EMPTY -2 /* marks an unused slot in redirtab */ 62 #define PIPESIZE 4096 /* amount of buffering in a pipe */ 63 64 65 MKINIT 66 struct redirtab { 67 struct redirtab *next; 68 short renamed[10]; 69 }; 70 71 72 MKINIT struct redirtab *redirlist; 73 74 /* 75 * We keep track of whether or not fd0 has been redirected. This is for 76 * background commands, where we want to redirect fd0 to /dev/null only 77 * if it hasn't already been redirected. 78 */ 79 int fd0_redirected = 0; 80 81 #ifdef __STDC__ 82 STATIC void openredirect(union node *, char *); 83 STATIC int openhere(union node *); 84 #else 85 STATIC void openredirect(); 86 STATIC int openhere(); 87 #endif 88 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; 106 int i; 107 int fd; 108 char memory[10]; /* file descriptors to write to memory */ 109 110 for (i = 10 ; --i >= 0 ; ) 111 memory[i] = 0; 112 memory[1] = flags & REDIR_BACKQ; 113 if (flags & REDIR_PUSH) { 114 sv = ckmalloc(sizeof (struct redirtab)); 115 for (i = 0 ; i < 10 ; i++) 116 sv->renamed[i] = EMPTY; 117 sv->next = redirlist; 118 redirlist = sv; 119 } 120 for (n = redir ; n ; n = n->nfile.next) { 121 fd = n->nfile.fd; 122 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { 123 INTOFF; 124 if ((i = copyfd(fd, 10)) != EMPTY) { 125 sv->renamed[fd] = i; 126 close(fd); 127 } 128 INTON; 129 if (i == EMPTY) 130 error("Out of file descriptors"); 131 } else { 132 close(fd); 133 } 134 if (fd == 0) 135 fd0_redirected++; 136 openredirect(n, memory); 137 } 138 if (memory[1]) 139 out1 = &memout; 140 if (memory[2]) 141 out2 = &memout; 142 } 143 144 145 STATIC void 146 openredirect(redir, memory) 147 union node *redir; 148 char memory[10]; 149 { 150 int fd = redir->nfile.fd; 151 char *fname; 152 int f; 153 154 /* 155 * We suppress interrupts so that we won't leave open file 156 * descriptors around. This may not be such a good idea because 157 * an open of a device or a fifo can block indefinitely. 158 */ 159 INTOFF; 160 memory[fd] = 0; 161 switch (redir->nfile.type) { 162 case NFROM: 163 fname = redir->nfile.expfname; 164 if ((f = open(fname, O_RDONLY)) < 0) 165 error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); 166 movefd: 167 if (f != fd) { 168 copyfd(f, fd); 169 close(f); 170 } 171 break; 172 case NTO: 173 fname = redir->nfile.expfname; 174 #ifdef O_CREAT 175 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 176 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 177 #else 178 if ((f = creat(fname, 0666)) < 0) 179 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 180 #endif 181 goto movefd; 182 case NAPPEND: 183 fname = redir->nfile.expfname; 184 #ifdef O_APPEND 185 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 186 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 187 #else 188 if ((f = open(fname, O_WRONLY)) < 0 189 && (f = creat(fname, 0666)) < 0) 190 error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); 191 lseek(f, (off_t)0, 2); 192 #endif 193 goto movefd; 194 case NTOFD: 195 case NFROMFD: 196 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 197 if (memory[redir->ndup.dupfd]) 198 memory[fd] = 1; 199 else 200 copyfd(redir->ndup.dupfd, fd); 201 } 202 break; 203 case NHERE: 204 case NXHERE: 205 f = openhere(redir); 206 goto movefd; 207 default: 208 abort(); 209 } 210 INTON; 211 } 212 213 214 /* 215 * Handle here documents. Normally we fork off a process to write the 216 * data to a pipe. If the document is short, we can stuff the data in 217 * the pipe without forking. 218 */ 219 220 STATIC int 221 openhere(redir) 222 union node *redir; 223 { 224 int pip[2]; 225 int len; 226 227 if (pipe(pip) < 0) 228 error("Pipe call failed"); 229 if (redir->type == NHERE) { 230 len = strlen(redir->nhere.doc->narg.text); 231 if (len <= PIPESIZE) { 232 xwrite(pip[1], redir->nhere.doc->narg.text, len); 233 goto out; 234 } 235 } 236 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 237 close(pip[0]); 238 signal(SIGINT, SIG_IGN); 239 signal(SIGQUIT, SIG_IGN); 240 signal(SIGHUP, SIG_IGN); 241 #ifdef SIGTSTP 242 signal(SIGTSTP, SIG_IGN); 243 #endif 244 signal(SIGPIPE, SIG_DFL); 245 if (redir->type == NHERE) 246 xwrite(pip[1], redir->nhere.doc->narg.text, len); 247 else 248 expandhere(redir->nhere.doc, pip[1]); 249 _exit(0); 250 } 251 out: 252 close(pip[1]); 253 return pip[0]; 254 } 255 256 257 258 /* 259 * Undo the effects of the last redirection. 260 */ 261 262 void 263 popredir() { 264 register struct redirtab *rp = redirlist; 265 int i; 266 267 for (i = 0 ; i < 10 ; i++) { 268 if (rp->renamed[i] != EMPTY) { 269 if (i == 0) 270 fd0_redirected--; 271 close(i); 272 if (rp->renamed[i] >= 0) { 273 copyfd(rp->renamed[i], i); 274 close(rp->renamed[i]); 275 } 276 } 277 } 278 INTOFF; 279 redirlist = rp->next; 280 ckfree(rp); 281 INTON; 282 } 283 284 /* 285 * Undo all redirections. Called on error or interrupt. 286 */ 287 288 #ifdef mkinit 289 290 INCLUDE "redir.h" 291 292 RESET { 293 while (redirlist) 294 popredir(); 295 } 296 297 SHELLPROC { 298 clearredir(); 299 } 300 301 #endif 302 303 /* Return true if fd 0 has already been redirected at least once. */ 304 int 305 fd0_redirected_p () { 306 return fd0_redirected != 0; 307 } 308 309 /* 310 * Discard all saved file descriptors. 311 */ 312 313 void 314 clearredir() { 315 register struct redirtab *rp; 316 int i; 317 318 for (rp = redirlist ; rp ; rp = rp->next) { 319 for (i = 0 ; i < 10 ; i++) { 320 if (rp->renamed[i] >= 0) { 321 close(rp->renamed[i]); 322 } 323 rp->renamed[i] = EMPTY; 324 } 325 } 326 } 327 328 329 330 /* 331 * Copy a file descriptor to be >= to. Returns -1 332 * if the source file descriptor is closed, EMPTY if there are no unused 333 * file descriptors left. 334 */ 335 336 int 337 copyfd(from, to) 338 int from; 339 int to; 340 { 341 int newfd; 342 343 newfd = fcntl(from, F_DUPFD, to); 344 if (newfd < 0 && errno == EMFILE) 345 return EMPTY; 346 return newfd; 347 } 348