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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#ifndef lint 34#if 0 35static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; 36#endif 37#endif /* not lint */ 38#include <sys/cdefs.h> 39__FBSDID("$FreeBSD$"); 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 CLOSED -1 /* fd was not open before redir */ 67#define PIPESIZE 4096 /* amount of buffering in a pipe */ 68 69 70MKINIT 71struct redirtab { 72 struct redirtab *next; 73 int renamed[10]; 74}; 75 76 77MKINIT struct redirtab *redirlist; 78 79/* 80 * We keep track of whether or not fd0 has been redirected. This is for 81 * background commands, where we want to redirect fd0 to /dev/null only 82 * if it hasn't already been redirected. 83*/ 84static int fd0_redirected = 0; 85 86static void openredirect(union node *, char[10 ]); 87static int openhere(union node *); 88 89 90/* 91 * Process a list of redirection commands. If the REDIR_PUSH flag is set, 92 * old file descriptors are stashed away so that the redirection can be 93 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the 94 * standard output, and the standard error if it becomes a duplicate of 95 * stdout, is saved in memory. 96* 97 * We suppress interrupts so that we won't leave open file 98 * descriptors around. Because the signal handler remains 99 * installed and we do not use system call restart, interrupts 100 * will still abort blocking opens such as fifos (they will fail 101 * with EINTR). There is, however, a race condition if an interrupt 102 * arrives after INTOFF and before open blocks. 103 */ 104 105void 106redirect(union node *redir, int flags) 107{ 108 union node *n; 109 struct redirtab *sv = NULL; 110 int i; 111 int fd; 112 char memory[10]; /* file descriptors to write to memory */ 113 114 INTOFF; 115 for (i = 10 ; --i >= 0 ; ) 116 memory[i] = 0; 117 memory[1] = flags & REDIR_BACKQ; 118 if (flags & REDIR_PUSH) { 119 sv = ckmalloc(sizeof (struct redirtab)); 120 for (i = 0 ; i < 10 ; i++) 121 sv->renamed[i] = EMPTY; 122 sv->next = redirlist; 123 redirlist = sv; 124 } 125 for (n = redir ; n ; n = n->nfile.next) { 126 fd = n->nfile.fd; 127 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && 128 n->ndup.dupfd == fd) 129 continue; /* redirect from/to same file descriptor */ 130 131 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { 132 INTOFF; 133 if ((i = fcntl(fd, F_DUPFD, 10)) == -1) { 134 switch (errno) { 135 case EBADF: 136 i = CLOSED; 137 break; 138 default: 139 INTON; 140 error("%d: %s", fd, strerror(errno)); 141 break; 142 } 143 } else 144 (void)fcntl(i, F_SETFD, FD_CLOEXEC); 145 sv->renamed[fd] = i; 146 INTON; 147 } 148 if (fd == 0) 149 fd0_redirected++; 150 openredirect(n, memory); 151 INTON; 152 INTOFF; 153 } 154 if (memory[1]) 155 out1 = &memout; 156 if (memory[2]) 157 out2 = &memout; 158 INTON; 159} 160 161 162static void 163openredirect(union node *redir, char memory[10]) 164{ 165 struct stat sb; 166 int fd = redir->nfile.fd; 167 char *fname; 168 int f; 169 int e; 170 171 memory[fd] = 0; 172 switch (redir->nfile.type) { 173 case NFROM: 174 fname = redir->nfile.expfname; 175 if ((f = open(fname, O_RDONLY)) < 0) 176 error("cannot open %s: %s", fname, strerror(errno)); 177movefd: 178 if (f != fd) { 179 if (dup2(f, fd) == -1) { 180 e = errno; 181 close(f); 182 error("%d: %s", fd, strerror(e)); 183 } 184 close(f); 185 } 186 break; 187 case NFROMTO: 188 fname = redir->nfile.expfname; 189 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0) 190 error("cannot create %s: %s", fname, strerror(errno)); 191 goto movefd; 192 case NTO: 193 if (Cflag) { 194 fname = redir->nfile.expfname; 195 if (stat(fname, &sb) == -1) { 196 if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0) 197 error("cannot create %s: %s", fname, strerror(errno)); 198 } else if (!S_ISREG(sb.st_mode)) { 199 if ((f = open(fname, O_WRONLY, 0666)) < 0) 200 error("cannot create %s: %s", fname, strerror(errno)); 201 if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) { 202 close(f); 203 error("cannot create %s: %s", fname, 204 strerror(EEXIST)); 205 } 206 } else 207 error("cannot create %s: %s", fname, 208 strerror(EEXIST)); 209 goto movefd; 210 } 211 /* FALLTHROUGH */ 212 case NCLOBBER: 213 fname = redir->nfile.expfname; 214 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 215 error("cannot create %s: %s", fname, strerror(errno)); 216 goto movefd; 217 case NAPPEND: 218 fname = redir->nfile.expfname; 219 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 220 error("cannot create %s: %s", fname, strerror(errno)); 221 goto movefd; 222 case NTOFD: 223 case NFROMFD: 224 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 225 if (memory[redir->ndup.dupfd]) 226 memory[fd] = 1; 227 else { 228 if (dup2(redir->ndup.dupfd, fd) < 0) 229 error("%d: %s", redir->ndup.dupfd, 230 strerror(errno)); 231 } 232 } else { 233 close(fd); 234 } 235 break; 236 case NHERE: 237 case NXHERE: 238 f = openhere(redir); 239 goto movefd; 240 default: 241 abort(); 242 } 243} 244 245 246/* 247 * Handle here documents. Normally we fork off a process to write the 248 * data to a pipe. If the document is short, we can stuff the data in 249 * the pipe without forking. 250 */ 251 252static int 253openhere(union node *redir) 254{ 255 int pip[2]; 256 int len = 0; 257 258 if (pipe(pip) < 0) 259 error("Pipe call failed: %s", strerror(errno)); 260 if (redir->type == NHERE) { 261 len = strlen(redir->nhere.doc->narg.text); 262 if (len <= PIPESIZE) { 263 xwrite(pip[1], redir->nhere.doc->narg.text, len); 264 goto out; 265 } 266 } 267 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 268 close(pip[0]); 269 signal(SIGINT, SIG_IGN); 270 signal(SIGQUIT, SIG_IGN); 271 signal(SIGHUP, SIG_IGN); 272 signal(SIGTSTP, SIG_IGN); 273 signal(SIGPIPE, SIG_DFL); 274 if (redir->type == NHERE) 275 xwrite(pip[1], redir->nhere.doc->narg.text, len); 276 else 277 expandhere(redir->nhere.doc, pip[1]); 278 _exit(0); 279 } 280out: 281 close(pip[1]); 282 return pip[0]; 283} 284 285 286 287/* 288 * Undo the effects of the last redirection. 289 */ 290 291void 292popredir(void) 293{ 294 struct redirtab *rp = redirlist; 295 int i; 296 297 for (i = 0 ; i < 10 ; i++) { 298 if (rp->renamed[i] != EMPTY) { 299 if (i == 0) 300 fd0_redirected--; 301 if (rp->renamed[i] >= 0) { 302 dup2(rp->renamed[i], i); 303 close(rp->renamed[i]); 304 } else { 305 close(i); 306 } 307 } 308 } 309 INTOFF; 310 redirlist = rp->next; 311 ckfree(rp); 312 INTON; 313} 314 315/* 316 * Undo all redirections. Called on error or interrupt. 317 */ 318 319#ifdef mkinit 320 321INCLUDE "redir.h" 322 323RESET { 324 while (redirlist) 325 popredir(); 326} 327 328#endif 329 330/* Return true if fd 0 has already been redirected at least once. */ 331int 332fd0_redirected_p(void) 333{ 334 return fd0_redirected != 0; 335} 336 337/* 338 * Discard all saved file descriptors. 339 */ 340 341void 342clearredir(void) 343{ 344 struct redirtab *rp; 345 int i; 346 347 for (rp = redirlist ; rp ; rp = rp->next) { 348 for (i = 0 ; i < 10 ; i++) { 349 if (rp->renamed[i] >= 0) { 350 close(rp->renamed[i]); 351 } 352 rp->renamed[i] = EMPTY; 353 } 354 } 355} 356