From e3cfc8ce61f788739c66445d903f8beacb40c93d Mon Sep 17 00:00:00 2001 From: rgrimes Date: Thu, 26 May 1994 06:18:55 +0000 Subject: BSD 4.4 Lite bin Sources --- bin/sh/redir.c | 343 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 343 insertions(+) create mode 100644 bin/sh/redir.c (limited to 'bin/sh/redir.c') diff --git a/bin/sh/redir.c b/bin/sh/redir.c new file mode 100644 index 0000000..b91ce5a --- /dev/null +++ b/bin/sh/redir.c @@ -0,0 +1,343 @@ +/*- + * 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 +static char sccsid[] = "@(#)redir.c 8.1 (Berkeley) 5/31/93"; +#endif /* not lint */ + +/* + * 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" +#include +#include +#include +#include +#include + + +#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; + +#ifdef __STDC__ +STATIC void openredirect(union node *, char *); +STATIC int openhere(union node *); +#else +STATIC void openredirect(); +STATIC int openhere(); +#endif + + + +/* + * 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 ((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; + + 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 newfd; + + newfd = fcntl(from, F_DUPFD, to); + if (newfd < 0 && errno == EMFILE) + return EMPTY; + return newfd; +} -- cgit v1.1