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 | #if 0
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36 | #ifndef lint
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37 | static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95";
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38 | #else
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39 | __RCSID("$NetBSD: redir.c,v 1.29 2004/07/08 03:57:33 christos Exp $");
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40 | #endif /* not lint */
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41 | #endif
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42 |
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43 | #include <sys/types.h>
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44 | #include <limits.h> /* PIPE_BUF */
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45 | #include <string.h>
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46 | #include <errno.h>
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47 | #include <stdlib.h>
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48 |
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49 | /*
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50 | * Code for dealing with input/output redirection.
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51 | */
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52 |
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53 | #include "main.h"
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54 | #include "shell.h"
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55 | #include "nodes.h"
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56 | #include "jobs.h"
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57 | #include "options.h"
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58 | #include "expand.h"
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59 | #include "redir.h"
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60 | #include "output.h"
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61 | #include "memalloc.h"
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62 | #include "error.h"
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63 | #include "shinstance.h"
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64 |
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65 |
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66 | #define EMPTY -2 /* marks an unused slot in redirtab */
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67 | #ifndef PIPE_BUF
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68 | # define PIPESIZE 4096 /* amount of buffering in a pipe */
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69 | #else
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70 | # define PIPESIZE PIPE_BUF
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71 | #endif
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72 |
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73 |
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74 | MKINIT
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75 | struct redirtab {
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76 | struct redirtab *next;
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77 | short renamed[10];
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78 | };
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79 |
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80 |
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81 | //MKINIT struct redirtab *redirlist;
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82 |
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83 | /*
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84 | * We keep track of whether or not fd0 has been redirected. This is for
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85 | * background commands, where we want to redirect fd0 to /dev/null only
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86 | * if it hasn't already been redirected.
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87 | */
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88 | //int fd0_redirected = 0;
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89 |
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90 | STATIC void openredirect(shinstance *, union node *, char[10], int);
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91 | STATIC int openhere(shinstance *, union node *);
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92 |
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93 |
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94 | /*
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95 | * Process a list of redirection commands. If the REDIR_PUSH flag is set,
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96 | * old file descriptors are stashed away so that the redirection can be
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97 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the
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98 | * standard output, and the standard error if it becomes a duplicate of
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99 | * stdout, is saved in memory.
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100 | */
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101 |
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102 | void
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103 | redirect(shinstance *psh, union node *redir, int flags)
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104 | {
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105 | union node *n;
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106 | struct redirtab *sv = NULL;
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107 | int i;
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108 | int fd;
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109 | int try;
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110 | char memory[10]; /* file descriptors to write to memory */
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111 |
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112 | for (i = 10 ; --i >= 0 ; )
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113 | memory[i] = 0;
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114 | memory[1] = flags & REDIR_BACKQ;
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115 | if (flags & REDIR_PUSH) {
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116 | /* We don't have to worry about REDIR_VFORK here, as
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117 | * flags & REDIR_PUSH is never true if REDIR_VFORK is set.
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118 | */
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119 | sv = ckmalloc(psh, sizeof (struct redirtab));
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120 | for (i = 0 ; i < 10 ; i++)
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121 | sv->renamed[i] = EMPTY;
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122 | sv->next = psh->redirlist;
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123 | psh->redirlist = sv;
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124 | }
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125 | for (n = redir ; n ; n = n->nfile.next) {
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126 | fd = n->nfile.fd;
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127 | try = 0;
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128 | if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) &&
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129 | n->ndup.dupfd == fd)
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130 | continue; /* redirect from/to same file descriptor */
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131 |
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132 | if ((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) {
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133 | INTOFF;
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134 | again:
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135 | if ((i = shfile_fcntl(&psh->fdtab, fd, F_DUPFD, 10)) == -1) {
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136 | switch (errno) {
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137 | case EBADF:
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138 | if (!try) {
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139 | openredirect(psh, n, memory, flags);
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140 | try++;
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141 | goto again;
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142 | }
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143 | /* FALLTHROUGH*/
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144 | default:
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145 | INTON;
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146 | error(psh, "%d: %s", fd, strerror(errno));
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147 | /* NOTREACHED */
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148 | }
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149 | }
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150 | if (!try) {
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151 | sv->renamed[fd] = i;
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152 | shfile_close(&psh->fdtab, fd);
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153 | }
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154 | INTON;
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155 | } else {
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156 | shfile_close(&psh->fdtab, fd);
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157 | }
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158 | if (fd == 0)
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159 | psh->fd0_redirected++;
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160 | if (!try)
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161 | openredirect(psh, n, memory, flags);
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162 | }
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163 | if (memory[1])
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164 | psh->out1 = &psh->memout;
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165 | if (memory[2])
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166 | psh->out2 = &psh->memout;
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167 | }
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168 |
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169 |
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170 | STATIC void
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171 | openredirect(shinstance *psh, union node *redir, char memory[10], int flags)
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172 | {
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173 | int fd = redir->nfile.fd;
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174 | char *fname;
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175 | int f;
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176 | int oflags = O_WRONLY|O_CREAT|O_TRUNC, eflags;
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177 |
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178 | /*
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179 | * We suppress interrupts so that we won't leave open file
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180 | * descriptors around. This may not be such a good idea because
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181 | * an open of a device or a fifo can block indefinitely.
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182 | */
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183 | INTOFF;
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184 | memory[fd] = 0;
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185 | switch (redir->nfile.type) {
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186 | case NFROM:
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187 | fname = redir->nfile.expfname;
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188 | if (flags & REDIR_VFORK)
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189 | eflags = O_NONBLOCK;
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190 | else
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191 | eflags = 0;
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192 | if ((f = shfile_open(&psh->fdtab, fname, O_RDONLY|eflags, 0)) < 0)
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193 | goto eopen;
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194 | if (eflags)
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195 | (void)shfile_fcntl(&psh->fdtab, f, F_SETFL, shfile_fcntl(&psh->fdtab, f, F_GETFL, 0) & ~eflags);
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196 | break;
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197 | case NFROMTO:
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198 | fname = redir->nfile.expfname;
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199 | if ((f = shfile_open(&psh->fdtab, fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0)
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200 | goto ecreate;
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201 | break;
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202 | case NTO:
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203 | if (Cflag(psh))
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204 | oflags |= O_EXCL;
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205 | /* FALLTHROUGH */
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206 | case NCLOBBER:
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207 | fname = redir->nfile.expfname;
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208 | if ((f = shfile_open(&psh->fdtab, fname, oflags, 0666)) < 0)
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209 | goto ecreate;
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210 | break;
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211 | case NAPPEND:
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212 | fname = redir->nfile.expfname;
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213 | if ((f = shfile_open(&psh->fdtab, fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0)
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214 | goto ecreate;
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215 | break;
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216 | case NTOFD:
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217 | case NFROMFD:
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218 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */
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219 | if (memory[redir->ndup.dupfd])
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220 | memory[fd] = 1;
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221 | else
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222 | copyfd(psh, redir->ndup.dupfd, fd);
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223 | }
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224 | INTON;
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225 | return;
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226 | case NHERE:
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227 | case NXHERE:
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228 | f = openhere(psh, redir);
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229 | break;
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230 | default:
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231 | sh_abort(psh);
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232 | }
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233 |
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234 | if (f != fd) {
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235 | movefd(psh, f, fd);
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236 | }
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237 | INTON;
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238 | return;
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239 | ecreate:
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240 | error(psh, "cannot create %s: %s", fname, errmsg(psh, errno, E_CREAT));
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241 | eopen:
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242 | error(psh, "cannot open %s: %s", fname, errmsg(psh, errno, E_OPEN));
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243 | }
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244 |
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245 |
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246 | /*
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247 | * Handle here documents. Normally we fork off a process to write the
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248 | * data to a pipe. If the document is short, we can stuff the data in
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249 | * the pipe without forking.
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250 | */
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251 |
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252 | STATIC int
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253 | openhere(shinstance *psh, union node *redir)
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254 | {
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255 | int pip[2];
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256 | size_t len = 0;
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257 |
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258 | if (shfile_pipe(&psh->fdtab, pip) < 0)
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259 | error(psh, "Pipe call failed");
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260 | if (redir->type == NHERE) {
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261 | len = strlen(redir->nhere.doc->narg.text);
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262 | if (len <= PIPESIZE) {
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263 | xwrite(psh, pip[1], redir->nhere.doc->narg.text, len);
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264 | goto out;
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265 | }
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266 | }
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267 | if (forkshell(psh, (struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) {
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268 | shfile_close(&psh->fdtab, pip[0]);
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269 | sh_signal(psh, SIGINT, SH_SIG_IGN);
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270 | sh_signal(psh, SIGQUIT, SH_SIG_IGN);
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271 | sh_signal(psh, SIGHUP, SH_SIG_IGN);
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272 | #ifdef SIGTSTP
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273 | sh_signal(psh, SIGTSTP, SH_SIG_IGN);
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274 | #endif
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275 | sh_signal(psh, SIGPIPE, SH_SIG_DFL);
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276 | if (redir->type == NHERE)
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277 | xwrite(psh, pip[1], redir->nhere.doc->narg.text, len);
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278 | else
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279 | expandhere(psh, redir->nhere.doc, pip[1]);
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280 | sh__exit(psh, 0);
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281 | }
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282 | out:
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283 | shfile_close(&psh->fdtab, pip[1]);
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284 | return pip[0];
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285 | }
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286 |
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287 |
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288 |
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289 | /*
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290 | * Undo the effects of the last redirection.
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291 | */
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292 |
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293 | void
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294 | popredir(shinstance *psh)
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295 | {
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296 | struct redirtab *rp = psh->redirlist;
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297 | int i;
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298 |
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299 | for (i = 0 ; i < 10 ; i++) {
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300 | if (rp->renamed[i] != EMPTY) {
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301 | if (i == 0)
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302 | psh->fd0_redirected--;
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303 | if (rp->renamed[i] >= 0) {
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304 | movefd(psh, rp->renamed[i], i);
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305 | } else {
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306 | shfile_close(&psh->fdtab, i);
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307 | }
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308 | }
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309 | }
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310 | INTOFF;
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311 | psh->redirlist = rp->next;
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312 | ckfree(psh, rp);
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313 | INTON;
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314 | }
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315 |
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316 | /*
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317 | * Undo all redirections. Called on error or interrupt.
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318 | */
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319 |
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320 | #ifdef mkinit
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321 |
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322 | INCLUDE "redir.h"
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323 |
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324 | RESET {
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325 | while (psh->redirlist)
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326 | popredir(psh);
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327 | }
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328 |
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329 | SHELLPROC {
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330 | clearredir(psh, 0);
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331 | }
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332 |
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333 | #endif
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334 |
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335 | /* Return true if fd 0 has already been redirected at least once. */
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336 | int
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337 | fd0_redirected_p(shinstance *psh) {
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338 | return psh->fd0_redirected != 0;
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339 | }
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340 |
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341 | /*
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342 | * Discard all saved file descriptors.
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343 | */
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344 |
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345 | void
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346 | clearredir(shinstance *psh, int vforked)
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347 | {
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348 | struct redirtab *rp;
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349 | int i;
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350 |
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351 | for (rp = psh->redirlist ; rp ; rp = rp->next) {
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352 | for (i = 0 ; i < 10 ; i++) {
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353 | if (rp->renamed[i] >= 0) {
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354 | shfile_close(&psh->fdtab, rp->renamed[i]);
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355 | }
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356 | if (!vforked)
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357 | rp->renamed[i] = EMPTY;
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358 | }
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359 | }
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360 | }
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361 |
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362 |
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363 |
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364 | /*
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365 | * Copy a file descriptor to be >= to. Returns -1
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366 | * if the source file descriptor is closed, EMPTY if there are no unused
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367 | * file descriptors left.
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368 | */
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369 |
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370 | int
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371 | copyfd(shinstance *psh, int from, int to)
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372 | {
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373 | int newfd;
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374 |
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375 | newfd = shfile_fcntl(&psh->fdtab, from, F_DUPFD, to);
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376 | if (newfd < 0) {
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377 | if (errno == EMFILE)
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378 | return EMPTY;
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379 | error(psh, "%d: %s", from, strerror(errno));
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380 | }
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381 | return newfd;
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382 | }
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383 |
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384 |
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385 | /*
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386 | * Move a file descriptor to be == to. Returns -1
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387 | * if the source file descriptor is closed, EMPTY if there are no unused
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388 | * file descriptors left.
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389 | */
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390 |
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391 | int
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392 | movefd(shinstance *psh, int from, int to)
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393 | {
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394 | int newfd;
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395 |
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396 | newfd = shfile_movefd(&psh->fdtab, from, to);
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397 | if (newfd < 0) {
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398 | if (errno == EMFILE)
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399 | return EMPTY;
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400 | error(psh, "%d: %s", from, strerror(errno));
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401 | }
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402 | return newfd;
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403 | }
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404 |
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405 |
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406 | /*
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407 | * Move a file descriptor to be >= to. Returns -1
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408 | * if the source file descriptor is closed, EMPTY if there are no unused
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409 | * file descriptors left.
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410 | */
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411 |
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412 | int
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413 | movefd_above(shinstance *psh, int from, int to)
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414 | {
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415 | int newfd;
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416 |
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417 | newfd = shfile_movefd_above(&psh->fdtab, from, to);
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418 | if (newfd < 0) {
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419 | if (errno == EMFILE)
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420 | return EMPTY;
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421 | error(psh, "%d: %s", from, strerror(errno));
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422 | }
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423 | return newfd;
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424 | }
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425 |
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