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 35 static 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 68 69 struct redirtab { 70 struct redirtab *next; 71 int renamed[10]; 72 int fd0_redirected; 73 }; 74 75 76 static struct redirtab *redirlist; 77 78 /* 79 * We keep track of whether or not fd0 has been redirected. This is for 80 * background commands, where we want to redirect fd0 to /dev/null only 81 * if it hasn't already been redirected. 82 */ 83 static int fd0_redirected = 0; 84 85 static void openredirect(union node *, char[10 ]); 86 static int openhere(union node *); 87 88 89 /* 90 * Process a list of redirection commands. If the REDIR_PUSH flag is set, 91 * old file descriptors are stashed away so that the redirection can be 92 * undone by calling popredir. If the REDIR_BACKQ flag is set, then the 93 * standard output, and the standard error if it becomes a duplicate of 94 * stdout, is saved in memory. 95 * 96 * We suppress interrupts so that we won't leave open file 97 * descriptors around. Because the signal handler remains 98 * installed and we do not use system call restart, interrupts 99 * will still abort blocking opens such as fifos (they will fail 100 * with EINTR). There is, however, a race condition if an interrupt 101 * arrives after INTOFF and before open blocks. 102 */ 103 104 void 105 redirect(union node *redir, int flags) 106 { 107 union node *n; 108 struct redirtab *sv = NULL; 109 int i; 110 int fd; 111 char memory[10]; /* file descriptors to write to memory */ 112 113 INTOFF; 114 for (i = 10 ; --i >= 0 ; ) 115 memory[i] = 0; 116 memory[1] = flags & REDIR_BACKQ; 117 if (flags & REDIR_PUSH) { 118 sv = ckmalloc(sizeof (struct redirtab)); 119 for (i = 0 ; i < 10 ; i++) 120 sv->renamed[i] = EMPTY; 121 sv->fd0_redirected = fd0_redirected; 122 sv->next = redirlist; 123 redirlist = sv; 124 } 125 for (n = redir ; n ; n = n->nfile.next) { 126 fd = n->nfile.fd; 127 if (fd == 0) 128 fd0_redirected = 1; 129 if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && 130 n->ndup.dupfd == fd) 131 continue; /* redirect from/to same file descriptor */ 132 133 if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { 134 INTOFF; 135 if ((i = fcntl(fd, F_DUPFD_CLOEXEC, 10)) == -1) { 136 switch (errno) { 137 case EBADF: 138 i = CLOSED; 139 break; 140 default: 141 INTON; 142 error("%d: %s", fd, strerror(errno)); 143 break; 144 } 145 } 146 sv->renamed[fd] = i; 147 INTON; 148 } 149 openredirect(n, memory); 150 INTON; 151 INTOFF; 152 } 153 if (memory[1]) 154 out1 = &memout; 155 if (memory[2]) 156 out2 = &memout; 157 INTON; 158 } 159 160 161 static void 162 openredirect(union node *redir, char memory[10]) 163 { 164 struct stat sb; 165 int fd = redir->nfile.fd; 166 const char *fname; 167 int f; 168 int e; 169 170 memory[fd] = 0; 171 switch (redir->nfile.type) { 172 case NFROM: 173 fname = redir->nfile.expfname; 174 if ((f = open(fname, O_RDONLY)) < 0) 175 error("cannot open %s: %s", fname, strerror(errno)); 176 movefd: 177 if (f != fd) { 178 if (dup2(f, fd) == -1) { 179 e = errno; 180 close(f); 181 error("%d: %s", fd, strerror(e)); 182 } 183 close(f); 184 } 185 break; 186 case NFROMTO: 187 fname = redir->nfile.expfname; 188 if ((f = open(fname, O_RDWR|O_CREAT, 0666)) < 0) 189 error("cannot create %s: %s", fname, strerror(errno)); 190 goto movefd; 191 case NTO: 192 if (Cflag) { 193 fname = redir->nfile.expfname; 194 if (stat(fname, &sb) == -1) { 195 if ((f = open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666)) < 0) 196 error("cannot create %s: %s", fname, strerror(errno)); 197 } else if (!S_ISREG(sb.st_mode)) { 198 if ((f = open(fname, O_WRONLY, 0666)) < 0) 199 error("cannot create %s: %s", fname, strerror(errno)); 200 if (fstat(f, &sb) != -1 && S_ISREG(sb.st_mode)) { 201 close(f); 202 error("cannot create %s: %s", fname, 203 strerror(EEXIST)); 204 } 205 } else 206 error("cannot create %s: %s", fname, 207 strerror(EEXIST)); 208 goto movefd; 209 } 210 /* FALLTHROUGH */ 211 case NCLOBBER: 212 fname = redir->nfile.expfname; 213 if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) 214 error("cannot create %s: %s", fname, strerror(errno)); 215 goto movefd; 216 case NAPPEND: 217 fname = redir->nfile.expfname; 218 if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) 219 error("cannot create %s: %s", fname, strerror(errno)); 220 goto movefd; 221 case NTOFD: 222 case NFROMFD: 223 if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ 224 if (memory[redir->ndup.dupfd]) 225 memory[fd] = 1; 226 else { 227 if (dup2(redir->ndup.dupfd, fd) < 0) 228 error("%d: %s", redir->ndup.dupfd, 229 strerror(errno)); 230 } 231 } else { 232 close(fd); 233 } 234 break; 235 case NHERE: 236 case NXHERE: 237 f = openhere(redir); 238 goto movefd; 239 default: 240 abort(); 241 } 242 } 243 244 245 /* 246 * Handle here documents. Normally we fork off a process to write the 247 * data to a pipe. If the document is short, we can stuff the data in 248 * the pipe without forking. 249 */ 250 251 static int 252 openhere(union node *redir) 253 { 254 const char *p; 255 int pip[2]; 256 size_t len = 0; 257 int flags; 258 ssize_t written = 0; 259 260 if (pipe(pip) < 0) 261 error("Pipe call failed: %s", strerror(errno)); 262 263 if (redir->type == NXHERE) 264 p = redir->nhere.expdoc; 265 else 266 p = redir->nhere.doc->narg.text; 267 len = strlen(p); 268 if (len == 0) 269 goto out; 270 flags = fcntl(pip[1], F_GETFL, 0); 271 if (flags != -1 && fcntl(pip[1], F_SETFL, flags | O_NONBLOCK) != -1) { 272 written = write(pip[1], p, len); 273 if (written < 0) 274 written = 0; 275 if ((size_t)written == len) 276 goto out; 277 fcntl(pip[1], F_SETFL, flags); 278 } 279 280 if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { 281 close(pip[0]); 282 signal(SIGINT, SIG_IGN); 283 signal(SIGQUIT, SIG_IGN); 284 signal(SIGHUP, SIG_IGN); 285 signal(SIGTSTP, SIG_IGN); 286 signal(SIGPIPE, SIG_DFL); 287 xwrite(pip[1], p + written, len - written); 288 _exit(0); 289 } 290 out: 291 close(pip[1]); 292 return pip[0]; 293 } 294 295 296 297 /* 298 * Undo the effects of the last redirection. 299 */ 300 301 void 302 popredir(void) 303 { 304 struct redirtab *rp = redirlist; 305 int i; 306 307 for (i = 0 ; i < 10 ; i++) { 308 if (rp->renamed[i] != EMPTY) { 309 if (rp->renamed[i] >= 0) { 310 dup2(rp->renamed[i], i); 311 close(rp->renamed[i]); 312 } else { 313 close(i); 314 } 315 } 316 } 317 INTOFF; 318 fd0_redirected = rp->fd0_redirected; 319 redirlist = rp->next; 320 ckfree(rp); 321 INTON; 322 } 323 324 /* Return true if fd 0 has already been redirected at least once. */ 325 int 326 fd0_redirected_p(void) 327 { 328 return fd0_redirected != 0; 329 } 330 331 /* 332 * Discard all saved file descriptors. 333 */ 334 335 void 336 clearredir(void) 337 { 338 struct redirtab *rp; 339 int i; 340 341 for (rp = redirlist ; rp ; rp = rp->next) { 342 for (i = 0 ; i < 10 ; i++) { 343 if (rp->renamed[i] >= 0) { 344 close(rp->renamed[i]); 345 } 346 rp->renamed[i] = EMPTY; 347 } 348 } 349 } 350