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2714 | cejka | 1 | /* $NetBSD: redir.c,v 1.22 2000/05/22 10:18:47 elric Exp $ */ |
2 | |||
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. All advertising materials mentioning features or use of this software |
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19 | * must display the following acknowledgement: |
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20 | * This product includes software developed by the University of |
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21 | * California, Berkeley and its contributors. |
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22 | * 4. Neither the name of the University nor the names of its contributors |
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23 | * may be used to endorse or promote products derived from this software |
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24 | * without specific prior written permission. |
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25 | * |
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26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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36 | * SUCH DAMAGE. |
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37 | */ |
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38 | |||
39 | #include <sys/cdefs.h> |
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40 | #ifndef lint |
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41 | #if 0 |
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42 | static char sccsid[] = "@(#)redir.c 8.2 (Berkeley) 5/4/95"; |
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43 | #else |
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44 | __RCSID("$NetBSD: redir.c,v 1.22 2000/05/22 10:18:47 elric Exp $"); |
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45 | #endif |
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46 | #endif /* not lint */ |
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47 | |||
48 | #include <sys/stat.h> |
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49 | #include <sys/types.h> |
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50 | #include <sys/param.h> /* PIPE_BUF */ |
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51 | #include <signal.h> |
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52 | #include <string.h> |
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53 | #include <fcntl.h> |
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54 | #include <errno.h> |
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55 | #include <unistd.h> |
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56 | #include <stdlib.h> |
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57 | |||
58 | /* |
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59 | * Code for dealing with input/output redirection. |
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60 | */ |
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61 | |||
62 | #include "shell.h" |
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63 | #include "nodes.h" |
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64 | #include "jobs.h" |
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65 | #include "expand.h" |
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66 | #include "redir.h" |
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67 | #include "output.h" |
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68 | #include "memalloc.h" |
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69 | #include "error.h" |
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70 | #include "options.h" |
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71 | |||
72 | |||
73 | #define EMPTY -2 /* marks an unused slot in redirtab */ |
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74 | #ifndef PIPE_BUF |
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75 | # define PIPESIZE 4096 /* amount of buffering in a pipe */ |
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76 | #else |
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77 | # define PIPESIZE PIPE_BUF |
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78 | #endif |
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79 | |||
80 | |||
81 | MKINIT |
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82 | struct redirtab { |
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83 | struct redirtab *next; |
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84 | short renamed[10]; |
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85 | }; |
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86 | |||
87 | |||
88 | MKINIT struct redirtab *redirlist; |
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89 | |||
90 | /* |
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91 | * We keep track of whether or not fd0 has been redirected. This is for |
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92 | * background commands, where we want to redirect fd0 to /dev/null only |
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93 | * if it hasn't already been redirected. |
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94 | */ |
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95 | int fd0_redirected = 0; |
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96 | |||
97 | /* |
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98 | * We also keep track of where fd2 goes. |
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99 | */ |
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100 | int fd2 = 2; |
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101 | |||
102 | STATIC int openredirect (union node *); |
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103 | STATIC void dupredirect (union node *, int, char[10 ]); |
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104 | STATIC int openhere (union node *); |
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105 | STATIC int noclobberopen (const char *); |
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106 | |||
107 | |||
108 | /* |
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109 | * Process a list of redirection commands. If the REDIR_PUSH flag is set, |
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110 | * old file descriptors are stashed away so that the redirection can be |
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111 | * undone by calling popredir. If the REDIR_BACKQ flag is set, then the |
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112 | * standard output, and the standard error if it becomes a duplicate of |
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113 | * stdout, is saved in memory. |
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114 | */ |
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115 | |||
116 | void |
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117 | redirect(redir, flags) |
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118 | union node *redir; |
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119 | int flags; |
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120 | { |
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121 | union node *n; |
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122 | struct redirtab *sv = NULL; |
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123 | int i; |
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124 | int fd; |
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125 | int newfd; |
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126 | int try; |
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127 | char memory[10]; /* file descriptors to write to memory */ |
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128 | |||
129 | for (i = 10 ; --i >= 0 ; ) |
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130 | memory[i] = 0; |
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131 | memory[1] = flags & REDIR_BACKQ; |
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132 | if (flags & REDIR_PUSH) { |
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133 | sv = ckmalloc(sizeof (struct redirtab)); |
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134 | for (i = 0 ; i < 10 ; i++) |
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135 | sv->renamed[i] = EMPTY; |
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136 | sv->next = redirlist; |
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137 | redirlist = sv; |
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138 | } |
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139 | for (n = redir ; n ; n = n->nfile.next) { |
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140 | fd = n->nfile.fd; |
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141 | try = 0; |
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142 | if ((n->nfile.type == NTOFD || n->nfile.type == NFROMFD) && |
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143 | n->ndup.dupfd == fd) |
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144 | continue; /* redirect from/to same file descriptor */ |
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145 | |||
146 | INTOFF; |
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147 | newfd = openredirect(n); |
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148 | if (((flags & REDIR_PUSH) && sv->renamed[fd] == EMPTY) || |
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149 | (fd == fd2)) { |
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150 | if (newfd == fd) { |
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151 | try++; |
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152 | } else if ((i = fcntl(fd, F_DUPFD, 10)) == -1) { |
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153 | switch (errno) { |
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154 | case EBADF: |
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155 | if (!try) { |
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156 | dupredirect(n, newfd, memory); |
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157 | try++; |
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158 | break; |
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159 | } |
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160 | /* FALLTHROUGH*/ |
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161 | default: |
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162 | if (newfd >= 0) { |
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163 | close(newfd); |
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164 | } |
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165 | INTON; |
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166 | error("%d: %s", fd, strerror(errno)); |
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167 | /* NOTREACHED */ |
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168 | } |
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169 | } |
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170 | if (!try) { |
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171 | close(fd); |
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172 | if (flags & REDIR_PUSH) { |
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173 | sv->renamed[fd] = i; |
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174 | } |
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175 | if (fd == fd2) { |
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176 | fd2 = i; |
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177 | } |
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178 | } |
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179 | } else if (fd != newfd) { |
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180 | close(fd); |
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181 | } |
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182 | if (fd == 0) |
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183 | fd0_redirected++; |
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184 | if (!try) |
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185 | dupredirect(n, newfd, memory); |
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186 | INTON; |
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187 | } |
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188 | if (memory[1]) |
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189 | out1 = &memout; |
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190 | if (memory[2]) |
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191 | out2 = &memout; |
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192 | } |
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193 | |||
194 | |||
195 | STATIC int |
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196 | openredirect(redir) |
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197 | union node *redir; |
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198 | { |
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199 | char *fname; |
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200 | int f; |
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201 | |||
202 | switch (redir->nfile.type) { |
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203 | case NFROM: |
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204 | fname = redir->nfile.expfname; |
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205 | if ((f = open(fname, O_RDONLY)) < 0) |
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206 | goto eopen; |
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207 | break; |
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208 | case NFROMTO: |
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209 | fname = redir->nfile.expfname; |
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210 | if ((f = open(fname, O_RDWR|O_CREAT|O_TRUNC, 0666)) < 0) |
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211 | goto ecreate; |
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212 | break; |
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213 | case NTO: |
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214 | /* Take care of noclobber mode. */ |
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215 | if (Cflag) { |
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216 | fname = redir->nfile.expfname; |
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217 | if ((f = noclobberopen(fname)) < 0) |
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218 | goto ecreate; |
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219 | break; |
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220 | } |
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221 | case NTOOV: |
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222 | fname = redir->nfile.expfname; |
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223 | #ifdef O_CREAT |
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224 | if ((f = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) < 0) |
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225 | goto ecreate; |
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226 | #else |
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227 | if ((f = creat(fname, 0666)) < 0) |
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228 | goto ecreate; |
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229 | #endif |
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230 | break; |
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231 | case NAPPEND: |
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232 | fname = redir->nfile.expfname; |
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233 | #ifdef O_APPEND |
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234 | if ((f = open(fname, O_WRONLY|O_CREAT|O_APPEND, 0666)) < 0) |
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235 | goto ecreate; |
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236 | #else |
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237 | if ((f = open(fname, O_WRONLY)) < 0 |
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238 | && (f = creat(fname, 0666)) < 0) |
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239 | goto ecreate; |
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240 | lseek(f, (off_t)0, 2); |
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241 | #endif |
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242 | break; |
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243 | case NTOFD: |
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244 | case NFROMFD: |
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245 | f = -1; |
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246 | break; |
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247 | case NHERE: |
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248 | case NXHERE: |
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249 | f = openhere(redir); |
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250 | break; |
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251 | default: |
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252 | abort(); |
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253 | } |
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254 | |||
255 | return f; |
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256 | ecreate: |
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257 | error("cannot create %s: %s", fname, errmsg(errno, E_CREAT)); |
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258 | eopen: |
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259 | error("cannot open %s: %s", fname, errmsg(errno, E_OPEN)); |
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260 | } |
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261 | |||
262 | |||
263 | STATIC void |
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264 | dupredirect(redir, f, memory) |
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265 | union node *redir; |
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266 | int f; |
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267 | char memory[10]; |
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268 | { |
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269 | int fd = redir->nfile.fd; |
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270 | |||
271 | memory[fd] = 0; |
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272 | if (redir->nfile.type == NTOFD || redir->nfile.type == NFROMFD) { |
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273 | if (redir->ndup.dupfd >= 0) { /* if not ">&-" */ |
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274 | if (memory[redir->ndup.dupfd]) |
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275 | memory[fd] = 1; |
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276 | else |
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277 | copyfd(redir->ndup.dupfd, fd); |
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278 | } |
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279 | return; |
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280 | } |
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281 | |||
282 | if (f != fd) { |
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283 | copyfd(f, fd); |
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284 | close(f); |
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285 | } |
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286 | return; |
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287 | } |
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288 | |||
289 | |||
290 | /* |
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291 | * Handle here documents. Normally we fork off a process to write the |
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292 | * data to a pipe. If the document is short, we can stuff the data in |
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293 | * the pipe without forking. |
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294 | */ |
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295 | |||
296 | STATIC int |
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297 | openhere(redir) |
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298 | union node *redir; |
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299 | { |
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300 | int pip[2]; |
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301 | int len = 0; |
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302 | |||
303 | if (pipe(pip) < 0) |
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304 | error("Pipe call failed"); |
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305 | if (redir->type == NHERE) { |
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306 | len = strlen(redir->nhere.doc->narg.text); |
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307 | if (len <= PIPESIZE) { |
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308 | xwrite(pip[1], redir->nhere.doc->narg.text, len); |
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309 | goto out; |
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310 | } |
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311 | } |
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312 | if (forkshell((struct job *)NULL, (union node *)NULL, FORK_NOJOB) == 0) { |
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313 | close(pip[0]); |
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314 | signal(SIGINT, SIG_IGN); |
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315 | signal(SIGQUIT, SIG_IGN); |
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316 | signal(SIGHUP, SIG_IGN); |
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317 | #ifdef SIGTSTP |
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318 | signal(SIGTSTP, SIG_IGN); |
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319 | #endif |
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320 | signal(SIGPIPE, SIG_DFL); |
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321 | if (redir->type == NHERE) |
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322 | xwrite(pip[1], redir->nhere.doc->narg.text, len); |
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323 | else |
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324 | expandhere(redir->nhere.doc, pip[1]); |
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325 | _exit(0); |
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326 | } |
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327 | out: |
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328 | close(pip[1]); |
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329 | return pip[0]; |
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330 | } |
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331 | |||
332 | |||
333 | |||
334 | /* |
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335 | * Undo the effects of the last redirection. |
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336 | */ |
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337 | |||
338 | void |
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339 | popredir() { |
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340 | struct redirtab *rp = redirlist; |
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341 | int i; |
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342 | |||
343 | INTOFF; |
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344 | for (i = 0 ; i < 10 ; i++) { |
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345 | if (rp->renamed[i] != EMPTY) { |
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346 | if (i == 0) |
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347 | fd0_redirected--; |
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348 | close(i); |
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349 | if (rp->renamed[i] >= 0) { |
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350 | copyfd(rp->renamed[i], i); |
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351 | close(rp->renamed[i]); |
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352 | } |
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353 | if (rp->renamed[i] == fd2) { |
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354 | fd2 = i; |
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355 | } |
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356 | } |
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357 | } |
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358 | redirlist = rp->next; |
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359 | ckfree(rp); |
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360 | INTON; |
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361 | } |
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362 | |||
363 | /* |
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364 | * Undo all redirections. Called on error or interrupt. |
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365 | */ |
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366 | |||
367 | #ifdef mkinit |
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368 | |||
369 | INCLUDE "redir.h" |
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370 | |||
371 | RESET { |
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372 | while (redirlist) |
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373 | popredir(); |
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374 | } |
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375 | |||
376 | SHELLPROC { |
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377 | clearredir(); |
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378 | } |
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379 | |||
380 | #endif |
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381 | |||
382 | /* Return true if fd 0 has already been redirected at least once. */ |
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383 | int |
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384 | fd0_redirected_p () { |
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385 | return fd0_redirected != 0; |
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386 | } |
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387 | |||
388 | /* |
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389 | * Discard all saved file descriptors. |
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390 | */ |
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391 | |||
392 | void |
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393 | clearredir() { |
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394 | struct redirtab *rp; |
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395 | int i; |
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396 | |||
397 | for (rp = redirlist ; rp ; rp = rp->next) { |
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398 | for (i = 0 ; i < 10 ; i++) { |
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399 | if (rp->renamed[i] >= 0) { |
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400 | close(rp->renamed[i]); |
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401 | if (rp->renamed[i] == fd2) { |
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402 | fd2 = -1; |
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403 | } |
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404 | } |
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405 | rp->renamed[i] = EMPTY; |
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406 | } |
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407 | } |
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408 | } |
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409 | |||
410 | |||
411 | |||
412 | /* |
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413 | * Copy a file descriptor to be >= to. Returns -1 |
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414 | * if the source file descriptor is closed, EMPTY if there are no unused |
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415 | * file descriptors left. |
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416 | */ |
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417 | |||
418 | int |
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419 | copyfd(from, to) |
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420 | int from; |
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421 | int to; |
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422 | { |
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423 | int newfd; |
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424 | |||
425 | newfd = fcntl(from, F_DUPFD, to); |
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426 | if (newfd < 0) { |
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427 | if (errno == EMFILE) |
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428 | return EMPTY; |
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429 | else |
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430 | error("%d: %s", from, strerror(errno)); |
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431 | } |
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432 | return newfd; |
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433 | } |
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434 | |||
435 | /* |
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436 | * Open a file in noclobber mode. |
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437 | * The code was copied from bash. |
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438 | */ |
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439 | int |
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440 | noclobberopen(fname) |
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441 | const char *fname; |
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442 | { |
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443 | int r, fd; |
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444 | struct stat finfo, finfo2; |
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445 | |||
446 | /* |
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447 | * If the file exists and is a regular file, return an error |
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448 | * immediately. |
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449 | */ |
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450 | r = stat(fname, &finfo); |
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451 | if (r == 0 && S_ISREG(finfo.st_mode)) { |
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452 | errno = EEXIST; |
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453 | return -1; |
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454 | } |
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455 | |||
456 | /* |
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457 | * If the file was not present (r != 0), make sure we open it |
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458 | * exclusively so that if it is created before we open it, our open |
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459 | * will fail. Make sure that we do not truncate an existing file. |
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460 | * Note that we don't turn on O_EXCL unless the stat failed -- if the |
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461 | * file was not a regular file, we leave O_EXCL off. |
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462 | */ |
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463 | if (r != 0) |
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464 | return open(fname, O_WRONLY|O_CREAT|O_EXCL, 0666); |
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465 | fd = open(fname, O_WRONLY|O_CREAT, 0666); |
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466 | |||
467 | /* If the open failed, return the file descriptor right away. */ |
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468 | if (fd < 0) |
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469 | return fd; |
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470 | |||
471 | /* |
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472 | * OK, the open succeeded, but the file may have been changed from a |
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473 | * non-regular file to a regular file between the stat and the open. |
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474 | * We are assuming that the O_EXCL open handles the case where FILENAME |
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475 | * did not exist and is symlinked to an existing file between the stat |
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476 | * and open. |
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477 | */ |
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478 | |||
479 | /* |
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480 | * If we can open it and fstat the file descriptor, and neither check |
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481 | * revealed that it was a regular file, and the file has not been |
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482 | * replaced, return the file descriptor. |
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483 | */ |
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484 | if (fstat(fd, &finfo2) == 0 && !S_ISREG(finfo2.st_mode) && |
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485 | finfo.st_dev == finfo2.st_dev && finfo.st_ino == finfo2.st_ino) |
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486 | return fd; |
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487 | |||
488 | /* The file has been replaced. badness. */ |
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489 | close(fd); |
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490 | errno = EEXIST; |
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491 | return -1; |
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492 | } |