/* $OpenBSD: redir.c,v 1.3 1996/10/20 00:55:03 millert Exp $ */ /* $NetBSD: redir.c,v 1.12 1995/05/11 21:30:10 christos Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Kenneth Almquist. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint #if 0 static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; #else static char rcsid[] = "$OpenBSD: redir.c,v 1.3 1996/10/20 00:55:03 millert Exp $"; #endif #endif /* not lint */ #include #include #include #include #include #include #include /* * Code for dealing with input/output redirection. */ #include "shell.h" #include "nodes.h" #include "jobs.h" #include "expand.h" #include "redir.h" #include "output.h" #include "memalloc.h" #include "error.h" #define EMPTY -2 /* marks an unused slot in redirtab */ #define PIPESIZE 4096 /* amount of buffering in a pipe */ MKINIT struct redirtab { struct redirtab *next; short renamed[10]; }; MKINIT struct redirtab *redirlist; /* * We keep track of whether or not fd0 has been redirected. This is for * background commands, where we want to redirect fd0 to /dev/null only * if it hasn't already been redirected. */ int fd0_redirected = 0; STATIC void openredirect __P((union node *, char[10 ])); STATIC int openhere __P((union node *)); /* * Process a list of redirection commands. If the REDIR_PUSH flag is set, * old file descriptors are stashed away so that the redirection can be * undone by calling popredir. If the REDIR_BACKQ flag is set, then the * standard output, and the standard error if it becomes a duplicate of * stdout, is saved in memory. */ void redirect(redir, flags) union node *redir; int flags; { union node *n; struct redirtab *sv; int i; int fd; char memory[10]; /* file descriptors to write to memory */ for (i = 10 ; --i >= 0 ; ) memory[i] = 0; memory[1] = flags & REDIR_BACKQ; if (flags & REDIR_PUSH) { sv = ckmalloc(sizeof (struct redirtab)); for (i = 0 ; i < 10 ; i++) sv->renamed[i] = EMPTY; sv->next = redirlist; redirlist = sv; } for (n = redir ; n ; n = n->nfile.next) { fd = n->nfile.fd; if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && n->ndup.dupfd == fd) continue; /* redirect from/to same file descriptor */ if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) { INTOFF; if ((i = copyfd(fd, 10)) != EMPTY) { sv->renamed[fd] = i; close(fd); } INTON; if (i == EMPTY) error("Out of file descriptors"); } else { close(fd); } if (fd == 0) fd0_redirected++; openredirect(n, memory); } if (memory[1]) out1 = &memout; if (memory[2]) out2 = &memout; } STATIC void openredirect(redir, memory) union node *redir; char memory[10]; { int fd = redir->nfile.fd; char *fname; int f; /* * We suppress interrupts so that we won't leave open file * descriptors around. This may not be such a good idea because * an open of a device or a fifo can block indefinitely. */ INTOFF; memory[fd] = 0; switch (redir->nfile.type) { case NFROM: fname = redir->nfile.expfname; if ((f = open(fname, O_RDONLY)) < 0) error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); movefd: if (f != fd) { copyfd(f, fd); close(f); } break; case NTO: fname = redir->nfile.expfname; #ifdef O_CREAT if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); #else if ((f = creat(fname, 0666)) < 0) error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); #endif goto movefd; case NAPPEND: fname = redir->nfile.expfname; #ifdef O_APPEND if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); #else if ((f = open(fname, O_WRONLY)) < 0 && (f = creat(fname, 0666)) < 0) error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); lseek(f, (off_t)0, 2); #endif goto movefd; case NTOFD: case NFROMFD: if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ if (memory[redir->ndup.dupfd]) memory[fd] = 1; else copyfd(redir->ndup.dupfd, fd); } break; case NHERE: case NXHERE: f = openhere(redir); goto movefd; default: abort(); } INTON; } /* * Handle here documents. Normally we fork off a process to write the * data to a pipe. If the document is short, we can stuff the data in * the pipe without forking. */ STATIC int openhere(redir) union node *redir; { int pip[2]; int len = 0; if (pipe(pip) < 0) error("Pipe call failed"); if (redir->type == NHERE) { len = strlen(redir->nhere.doc->narg.text); if (len <= PIPESIZE) { xwrite(pip[1], redir->nhere.doc->narg.text, len); goto out; } } if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { close(pip[0]); signal(SIGINT, SIG_IGN); signal(SIGQUIT, SIG_IGN); signal(SIGHUP, SIG_IGN); #ifdef SIGTSTP signal(SIGTSTP, SIG_IGN); #endif signal(SIGPIPE, SIG_DFL); if (redir->type == NHERE) xwrite(pip[1], redir->nhere.doc->narg.text, len); else expandhere(redir->nhere.doc, pip[1]); _exit(0); } out: close(pip[1]); return pip[0]; } /* * Undo the effects of the last redirection. */ void popredir() { register struct redirtab *rp = redirlist; int i; for (i = 0 ; i < 10 ; i++) { if (rp->renamed[i] != EMPTY) { if (i == 0) fd0_redirected--; close(i); if (rp->renamed[i] >= 0) { copyfd(rp->renamed[i], i); close(rp->renamed[i]); } } } INTOFF; redirlist = rp->next; ckfree(rp); INTON; } /* * Undo all redirections. Called on error or interrupt. */ #ifdef mkinit INCLUDE "redir.h" RESET { while (redirlist) popredir(); } SHELLPROC { clearredir(); } #endif /* Return true if fd 0 has already been redirected at least once. */ int fd0_redirected_p () { return fd0_redirected != 0; } /* * Discard all saved file descriptors. */ void clearredir() { register struct redirtab *rp; int i; for (rp = redirlist ; rp ; rp = rp->next) { for (i = 0 ; i < 10 ; i++) { if (rp->renamed[i] >= 0) { close(rp->renamed[i]); } rp->renamed[i] = EMPTY; } } } /* * Copy a file descriptor to be >= to. Returns -1 * if the source file descriptor is closed, EMPTY if there are no unused * file descriptors left. */ int copyfd(from, to) int from; int to; { int newfd; newfd = fcntl(from, F_DUPFD, to); if (newfd < 0) { if (errno == EMFILE) return EMPTY; else error("%d: %s", from, strerror(errno)); } return newfd; }