| 1 | /* $NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $ */
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| 2 |
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| 3 | /*-
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| 4 | * Copyright (c) 1991, 1993
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| 5 | * The Regents of the University of California. All rights reserved.
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| 6 | *
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| 7 | * This code is derived from software contributed to Berkeley by
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| 8 | * Kenneth Almquist.
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| 9 | *
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| 10 | * Redistribution and use in source and binary forms, with or without
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| 11 | * modification, are permitted provided that the following conditions
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| 12 | * are met:
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| 13 | * 1. Redistributions of source code must retain the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer.
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| 15 | * 2. Redistributions in binary form must reproduce the above copyright
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| 16 | * notice, this list of conditions and the following disclaimer in the
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| 17 | * documentation and/or other materials provided with the distribution.
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| 18 | * 3. Neither the name of the University nor the names of its contributors
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| 19 | * may be used to endorse or promote products derived from this software
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| 20 | * without specific prior written permission.
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| 21 | *
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| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 32 | * SUCH DAMAGE.
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| 33 | */
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| 34 |
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| 35 | #ifdef HAVE_SYS_CDEFS_H
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| 36 | #include <sys/cdefs.h>
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| 37 | #endif
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| 38 | #ifndef lint
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| 39 | #if 0
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| 40 | static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
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| 41 | #else
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| 42 | __RCSID("$NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $");
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| 43 | #endif
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| 44 | #endif /* not lint */
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| 45 |
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| 46 | #include <sys/types.h>
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| 47 | #include <sys/param.h> /* PIPE_BUF */
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| 48 | #include <signal.h>
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| 49 | #include <string.h>
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| 50 | #include <fcntl.h>
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| 51 | #include <errno.h>
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| 52 | #include <unistd.h>
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| 53 | #include <stdlib.h>
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| 54 |
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| 55 | /*
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| 56 | * Code for dealing with input/output redirection.
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| 57 | */
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| 58 |
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| 59 | #include "main.h"
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| 60 | #include "shell.h"
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| 61 | #include "nodes.h"
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| 62 | #include "jobs.h"
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| 63 | #include "options.h"
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| 64 | #include "expand.h"
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| 65 | #include "redir.h"
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| 66 | #include "output.h"
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| 67 | #include "memalloc.h"
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| 68 | #include "error.h"
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| 69 | #include "shinstance.h"
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| 70 |
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| 71 |
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| 72 | #define EMPTY -2 /* marks an unused slot in redirtab */
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| 73 | #ifndef PIPE_BUF
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| 74 | # define PIPESIZE 4096 /* amount of buffering in a pipe */
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| 75 | #else
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| 76 | # define PIPESIZE PIPE_BUF
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| 77 | #endif
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| 78 |
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| 79 |
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| 80 | MKINIT
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| 81 | struct redirtab {
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| 82 | struct redirtab *next;
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| 83 | short renamed[10];
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| 84 | };
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| 85 |
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| 86 |
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| 87 | //MKINIT struct redirtab *redirlist;
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| 88 |
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| 89 | /*
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| 90 | * We keep track of whether or not fd0 has been redirected. This is for
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| 91 | * background commands, where we want to redirect fd0 to /dev/null only
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| 92 | * if it hasn't already been redirected.
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| 93 | */
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| 94 | //int fd0_redirected = 0;
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| 95 |
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| 96 | STATIC void openredirect(shinstance *, union node *, char[10], int);
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| 97 | STATIC int openhere(shinstance *, union node *);
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| 98 |
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| 99 |
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| 100 | /*
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| 101 | * Process a list of redirection commands. If the REDIR_PUSH flag is set,
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| 102 | * old file descriptors are stashed away so that the redirection can be
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| 103 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
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| 104 | * standard output, and the standard error if it becomes a duplicate of
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| 105 | * stdout, is saved in memory.
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| 106 | */
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| 107 |
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| 108 | void
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| 109 | redirect(shinstance *psh, union node *redir, int flags)
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| 110 | {
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| 111 | union node *n;
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| 112 | struct redirtab *sv = NULL;
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| 113 | int i;
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| 114 | int fd;
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| 115 | int try;
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| 116 | char memory[10]; /* file descriptors to write to memory */
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| 117 |
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| 118 | for (i = 10 ; --i >= 0 ; )
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| 119 | memory[i] = 0;
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| 120 | memory[1] = flags & REDIR_BACKQ;
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| 121 | if (flags & REDIR_PUSH) {
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| 122 | /* We don't have to worry about REDIR_VFORK here, as
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| 123 | * flags & REDIR_PUSH is never true if REDIR_VFORK is set.
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| 124 | */
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| 125 | sv = ckmalloc(sizeof (struct redirtab));
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| 126 | for (i = 0 ; i < 10 ; i++)
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| 127 | sv->renamed[i] = EMPTY;
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| 128 | sv->next = psh->redirlist;
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| 129 | psh->redirlist = sv;
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| 130 | }
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| 131 | for (n = redir ; n ; n = n->nfile.next) {
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| 132 | fd = n->nfile.fd;
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| 133 | try = 0;
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| 134 | if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
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| 135 | n->ndup.dupfd == fd)
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| 136 | continue; /* redirect from/to same file descriptor */
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| 137 |
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| 138 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
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| 139 | INTOFF;
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| 140 | again:
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| 141 | if ((i = shfile_fcntl(&psh->fdtab, fd, F_DUPFD, 10)) == -1) {
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| 142 | switch (errno) {
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| 143 | case EBADF:
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| 144 | if (!try) {
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| 145 | openredirect(psh, n, memory, flags);
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| 146 | try++;
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| 147 | goto again;
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| 148 | }
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| 149 | /* FALLTHROUGH*/
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| 150 | default:
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| 151 | INTON;
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| 152 | error(psh, "%d: %s", fd, strerror(errno));
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| 153 | /* NOTREACHED */
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| 154 | }
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| 155 | }
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| 156 | if (!try) {
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| 157 | sv->renamed[fd] = i;
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| 158 | shfile_close(&psh->fdtab, fd);
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| 159 | }
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| 160 | INTON;
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| 161 | } else {
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| 162 | shfile_close(&psh->fdtab, fd);
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| 163 | }
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| 164 | if (fd == 0)
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| 165 | psh->fd0_redirected++;
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| 166 | if (!try)
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| 167 | openredirect(psh, n, memory, flags);
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| 168 | }
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| 169 | if (memory[1])
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| 170 | psh->out1 = &psh->memout;
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| 171 | if (memory[2])
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| 172 | psh->out2 = &psh->memout;
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| 173 | }
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| 174 |
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| 175 |
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| 176 | STATIC void
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| 177 | openredirect(shinstance *psh, union node *redir, char memory[10], int flags)
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| 178 | {
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| 179 | int fd = redir->nfile.fd;
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| 180 | char *fname;
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| 181 | int f;
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| 182 | int oflags = O_WRONLY|O_CREAT|O_TRUNC, eflags;
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| 183 |
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| 184 | /*
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| 185 | * We suppress interrupts so that we won't leave open file
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| 186 | * descriptors around. This may not be such a good idea because
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| 187 | * an open of a device or a fifo can block indefinitely.
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| 188 | */
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| 189 | INTOFF;
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| 190 | memory[fd] = 0;
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| 191 | switch (redir->nfile.type) {
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| 192 | case NFROM:
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| 193 | fname = redir->nfile.expfname;
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| 194 | if (flags & REDIR_VFORK)
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| 195 | eflags = O_NONBLOCK;
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| 196 | else
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| 197 | eflags = 0;
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| 198 | if ((f = open(fname, O_RDONLY|eflags)) < 0)
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| 199 | goto eopen;
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| 200 | if (eflags)
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| 201 | (void)shfile_fcntl(&psh->fdtab, f, F_SETFL, shfile_fcntl(&psh->fdtab, f, F_GETFL, 0) & ~eflags);
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| 202 | break;
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| 203 | case NFROMTO:
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| 204 | fname = redir->nfile.expfname;
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| 205 | if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0)
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| 206 | goto ecreate;
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| 207 | break;
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| 208 | case NTO:
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| 209 | if (Cflag(psh))
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| 210 | oflags |= O_EXCL;
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| 211 | /* FALLTHROUGH */
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| 212 | case NCLOBBER:
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| 213 | fname = redir->nfile.expfname;
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| 214 | if ((f = open(fname, oflags, 0666)) < 0)
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| 215 | goto ecreate;
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| 216 | break;
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| 217 | case NAPPEND:
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| 218 | fname = redir->nfile.expfname;
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| 219 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
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| 220 | goto ecreate;
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| 221 | break;
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| 222 | case NTOFD:
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| 223 | case NFROMFD:
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| 224 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
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| 225 | if (memory[redir->ndup.dupfd])
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| 226 | memory[fd] = 1;
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| 227 | else
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| 228 | copyfd(psh, redir->ndup.dupfd, fd);
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| 229 | }
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| 230 | INTON;
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| 231 | return;
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| 232 | case NHERE:
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| 233 | case NXHERE:
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| 234 | f = openhere(psh, redir);
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| 235 | break;
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| 236 | default:
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| 237 | abort();
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| 238 | }
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| 239 |
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| 240 | if (f != fd) {
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| 241 | copyfd(psh, f, fd);
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| 242 | shfile_close(&psh->fdtab, f);
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| 243 | }
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| 244 | INTON;
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| 245 | return;
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| 246 | ecreate:
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| 247 | error(psh, "cannot create %s: %s", fname, errmsg(psh, errno, E_CREAT));
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| 248 | eopen:
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| 249 | error(psh, "cannot open %s: %s", fname, errmsg(psh, errno, E_OPEN));
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| 250 | }
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| 251 |
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| 252 |
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| 253 | /*
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| 254 | * Handle here documents. Normally we fork off a process to write the
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| 255 | * data to a pipe. If the document is short, we can stuff the data in
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| 256 | * the pipe without forking.
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| 257 | */
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| 258 |
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| 259 | STATIC int
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| 260 | openhere(shinstance *psh, union node *redir)
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| 261 | {
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| 262 | int pip[2];
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| 263 | size_t len = 0;
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| 264 |
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| 265 | if (shfile_pipe(&psh->fdtab, pip) < 0)
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| 266 | error(psh, "Pipe call failed");
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| 267 | if (redir->type == NHERE) {
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| 268 | len = strlen(redir->nhere.doc->narg.text);
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| 269 | if (len <= PIPESIZE) {
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| 270 | xwrite(psh, pip[1], redir->nhere.doc->narg.text, len);
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| 271 | goto out;
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| 272 | }
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| 273 | }
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| 274 | if (forkshell(psh, (struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
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| 275 | shfile_close(&psh->fdtab, pip[0]);
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| 276 | sh_signal(psh, SIGINT, SH_SIG_IGN);
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| 277 | sh_signal(psh, SIGQUIT, SH_SIG_IGN);
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| 278 | sh_signal(psh, SIGHUP, SH_SIG_IGN);
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| 279 | #ifdef SIGTSTP
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| 280 | sh_signal(psh, SIGTSTP, SH_SIG_IGN);
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| 281 | #endif
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| 282 | sh_signal(psh, SIGPIPE, SH_SIG_DFL);
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| 283 | if (redir->type == NHERE)
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| 284 | xwrite(psh, pip[1], redir->nhere.doc->narg.text, len);
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| 285 | else
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| 286 | expandhere(psh, redir->nhere.doc, pip[1]);
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| 287 | sh__exit(psh, 0);
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| 288 | }
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| 289 | out:
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| 290 | shfile_close(&psh->fdtab, pip[1]);
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| 291 | return pip[0];
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| 292 | }
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| 293 |
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| 294 |
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| 295 |
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| 296 | /*
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| 297 | * Undo the effects of the last redirection.
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| 298 | */
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| 299 |
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| 300 | void
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| 301 | popredir(shinstance *psh)
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| 302 | {
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| 303 | struct redirtab *rp = psh->redirlist;
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| 304 | int i;
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| 305 |
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| 306 | for (i = 0 ; i < 10 ; i++) {
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| 307 | if (rp->renamed[i] != EMPTY) {
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| 308 | if (i == 0)
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| 309 | psh->fd0_redirected--;
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| 310 | shfile_close(&psh->fdtab, i);
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| 311 | if (rp->renamed[i] >= 0) {
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| 312 | copyfd(psh, rp->renamed[i], i);
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| 313 | shfile_close(&psh->fdtab, rp->renamed[i]);
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| 314 | }
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| 315 | }
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| 316 | }
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| 317 | INTOFF;
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| 318 | psh->redirlist = rp->next;
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| 319 | ckfree(rp);
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| 320 | INTON;
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| 321 | }
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| 322 |
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| 323 | /*
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| 324 | * Undo all redirections. Called on error or interrupt.
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| 325 | */
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| 326 |
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| 327 | #ifdef mkinit
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| 328 |
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| 329 | INCLUDE "redir.h"
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| 330 |
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| 331 | RESET {
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| 332 | while (psh->redirlist)
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| 333 | popredir(psh);
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| 334 | }
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| 335 |
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| 336 | SHELLPROC {
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| 337 | clearredir(psh, 0);
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| 338 | }
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| 339 |
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| 340 | #endif
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| 341 |
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| 342 | /* Return true if fd 0 has already been redirected at least once. */
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| 343 | int
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| 344 | fd0_redirected_p(shinstance *psh) {
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| 345 | return psh->fd0_redirected != 0;
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| 346 | }
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| 347 |
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| 348 | /*
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| 349 | * Discard all saved file descriptors.
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| 350 | */
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| 351 |
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| 352 | void
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| 353 | clearredir(shinstance *psh, int vforked)
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| 354 | {
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| 355 | struct redirtab *rp;
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| 356 | int i;
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| 357 |
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| 358 | for (rp = psh->redirlist ; rp ; rp = rp->next) {
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| 359 | for (i = 0 ; i < 10 ; i++) {
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| 360 | if (rp->renamed[i] >= 0) {
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| 361 | shfile_close(&psh->fdtab, rp->renamed[i]);
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| 362 | }
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| 363 | if (!vforked)
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| 364 | rp->renamed[i] = EMPTY;
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| 365 | }
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| 366 | }
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| 367 | }
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| 368 |
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| 369 |
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| 370 |
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| 371 | /*
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| 372 | * Copy a file descriptor to be >= to. Returns -1
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| 373 | * if the source file descriptor is closed, EMPTY if there are no unused
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| 374 | * file descriptors left.
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| 375 | */
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| 376 |
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| 377 | int
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| 378 | copyfd(shinstance *psh, int from, int to)
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| 379 | {
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| 380 | int newfd;
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| 381 |
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| 382 | newfd = shfile_fcntl(&psh->fdtab, from, F_DUPFD, to);
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| 383 | if (newfd < 0) {
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| 384 | if (errno == EMFILE)
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| 385 | return EMPTY;
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| 386 | else
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| 387 | error(psh, "%d: %s", from, strerror(errno));
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| 388 | }
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| 389 | return newfd;
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| 390 | }
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