1 | /* $NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl 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[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
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41 | #else
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42 | __RCSID("$NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl 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/stat.h>
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48 | #include <stdlib.h>
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49 | #include <string.h>
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50 | #include <unistd.h>
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51 | #include <errno.h>
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52 |
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53 | /*
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54 | * The cd and pwd commands.
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55 | */
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56 |
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57 | #include "shell.h"
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58 | #include "var.h"
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59 | #include "nodes.h" /* for jobs.h */
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60 | #include "jobs.h"
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61 | #include "options.h"
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62 | #include "output.h"
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63 | #include "memalloc.h"
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64 | #include "error.h"
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65 | #include "exec.h"
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66 | #include "redir.h"
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67 | #include "mystring.h"
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68 | #include "show.h"
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69 | #include "cd.h"
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70 |
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71 | STATIC int docd(char *, int);
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72 | STATIC char *getcomponent(void);
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73 | STATIC void updatepwd(char *);
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74 | STATIC void find_curdir(int noerror);
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75 |
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76 | char *curdir = NULL; /* current working directory */
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77 | char *prevdir; /* previous working directory */
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78 | STATIC char *cdcomppath;
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79 |
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80 | int
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81 | cdcmd(int argc, char **argv)
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82 | {
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83 | const char *dest;
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84 | const char *path;
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85 | char *p, *d;
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86 | struct stat statb;
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87 | int print = cdprint; /* set -cdprint to enable */
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88 |
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89 | nextopt(nullstr);
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90 |
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91 | /*
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92 | * Try (quite hard) to have 'curdir' defined, nothing has set
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93 | * it on entry to the shell, but we want 'cd fred; cd -' to work.
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94 | */
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95 | getpwd(1);
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96 | dest = *argptr;
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97 | if (dest == NULL) {
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98 | dest = bltinlookup("HOME", 1);
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99 | if (dest == NULL)
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100 | error("HOME not set");
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101 | } else {
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102 | if (argptr[1]) {
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103 | /* Do 'ksh' style substitution */
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104 | if (!curdir)
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105 | error("PWD not set");
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106 | p = strstr(curdir, dest);
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107 | if (!p)
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108 | error("bad substitution");
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109 | d = stalloc(strlen(curdir) + strlen(argptr[1]) + 1);
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110 | memcpy(d, curdir, p - curdir);
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111 | strcpy(d + (p - curdir), argptr[1]);
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112 | strcat(d, p + strlen(dest));
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113 | dest = d;
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114 | print = 1;
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115 | }
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116 | }
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117 |
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118 | if (dest[0] == '-' && dest[1] == '\0') {
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119 | dest = prevdir ? prevdir : curdir;
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120 | print = 1;
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121 | }
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122 | if (*dest == '\0')
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123 | dest = ".";
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124 | if (IS_ROOT(dest) || (path = bltinlookup("CDPATH", 1)) == NULL)
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125 | path = nullstr;
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126 | while ((p = padvance(&path, dest)) != NULL) {
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127 | if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
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128 | if (!print) {
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129 | /*
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130 | * XXX - rethink
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131 | */
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132 | if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
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133 | p += 2;
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134 | print = strcmp(p, dest);
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135 | }
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136 | if (docd(p, print) >= 0)
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137 | return 0;
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138 |
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139 | }
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140 | }
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141 | error("can't cd to %s", dest);
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142 | /* NOTREACHED */
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143 | }
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144 |
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145 |
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146 | /*
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147 | * Actually do the chdir. In an interactive shell, print the
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148 | * directory name if "print" is nonzero.
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149 | */
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150 |
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151 | STATIC int
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152 | docd(char *dest, int print)
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153 | {
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154 | char *p;
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155 | char *q;
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156 | char *component;
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157 | struct stat statb;
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158 | int first;
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159 | int badstat;
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160 |
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161 | TRACE(("docd(\"%s\", %d) called\n", dest, print));
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162 |
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163 | /*
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164 | * Check each component of the path. If we find a symlink or
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165 | * something we can't stat, clear curdir to force a getcwd()
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166 | * next time we get the value of the current directory.
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167 | */
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168 | badstat = 0;
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169 | cdcomppath = stalloc(strlen(dest) + 1);
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170 | scopy(dest, cdcomppath);
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171 | STARTSTACKSTR(p);
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172 | if (IS_ROOT(dest)) {
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173 | STPUTC('/', p);
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174 | cdcomppath++;
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175 | }
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176 | first = 1;
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177 | while ((q = getcomponent()) != NULL) {
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178 | if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
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179 | continue;
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180 | if (! first)
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181 | STPUTC('/', p);
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182 | first = 0;
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183 | component = q;
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184 | while (*q)
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185 | STPUTC(*q++, p);
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186 | if (equal(component, ".."))
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187 | continue;
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188 | STACKSTRNUL(p);
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189 | if ((lstat(stackblock(), &statb) < 0)
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190 | || (S_ISLNK(statb.st_mode))) {
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191 | /* print = 1; */
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192 | badstat = 1;
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193 | break;
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194 | }
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195 | }
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196 |
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197 | INTOFF;
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198 | if (chdir(dest) < 0) {
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199 | INTON;
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200 | return -1;
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201 | }
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202 | updatepwd(badstat ? NULL : dest);
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203 | INTON;
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204 | if (print && iflag && curdir)
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205 | out1fmt("%s\n", curdir);
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206 | return 0;
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207 | }
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208 |
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209 |
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210 | /*
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211 | * Get the next component of the path name pointed to by cdcomppath.
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212 | * This routine overwrites the string pointed to by cdcomppath.
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213 | */
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214 |
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215 | STATIC char *
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216 | getcomponent()
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217 | {
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218 | char *p;
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219 | char *start;
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220 |
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221 | if ((p = cdcomppath) == NULL)
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222 | return NULL;
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223 | start = cdcomppath;
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224 | while (*p != '/' && *p != '\0')
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225 | p++;
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226 | if (*p == '\0') {
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227 | cdcomppath = NULL;
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228 | } else {
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229 | *p++ = '\0';
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230 | cdcomppath = p;
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231 | }
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232 | return start;
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233 | }
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234 |
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235 |
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236 |
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237 | /*
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238 | * Update curdir (the name of the current directory) in response to a
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239 | * cd command. We also call hashcd to let the routines in exec.c know
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240 | * that the current directory has changed.
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241 | */
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242 |
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243 | STATIC void
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244 | updatepwd(char *dir)
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245 | {
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246 | char *new;
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247 | char *p;
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248 |
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249 | hashcd(); /* update command hash table */
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250 |
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251 | /*
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252 | * If our argument is NULL, we don't know the current directory
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253 | * any more because we traversed a symbolic link or something
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254 | * we couldn't stat().
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255 | */
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256 | if (dir == NULL || curdir == NULL) {
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257 | if (prevdir)
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258 | ckfree(prevdir);
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259 | INTOFF;
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260 | prevdir = curdir;
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261 | curdir = NULL;
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262 | getpwd(1);
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263 | INTON;
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264 | if (curdir)
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265 | setvar("PWD", curdir, VEXPORT);
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266 | else
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267 | unsetvar("PWD", 0);
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268 | return;
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269 | }
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270 | cdcomppath = stalloc(strlen(dir) + 1);
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271 | scopy(dir, cdcomppath);
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272 | STARTSTACKSTR(new);
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273 | if (!IS_ROOT(dir)) {
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274 | p = curdir;
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275 | while (*p)
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276 | STPUTC(*p++, new);
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277 | if (p[-1] == '/')
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278 | STUNPUTC(new);
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279 | }
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280 | while ((p = getcomponent()) != NULL) {
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281 | if (equal(p, "..")) {
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282 | while (new > stackblock() && (STUNPUTC(new), *new) != '/');
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283 | } else if (*p != '\0' && ! equal(p, ".")) {
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284 | STPUTC('/', new);
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285 | while (*p)
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286 | STPUTC(*p++, new);
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287 | }
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288 | }
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289 | if (new == stackblock())
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290 | STPUTC('/', new);
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291 | STACKSTRNUL(new);
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292 | INTOFF;
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293 | if (prevdir)
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294 | ckfree(prevdir);
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295 | prevdir = curdir;
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296 | curdir = savestr(stackblock());
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297 | setvar("PWD", curdir, VEXPORT);
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298 | INTON;
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299 | }
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300 |
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301 | /*
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302 | * Posix says the default should be 'pwd -L' (as below), however
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303 | * the 'cd' command (above) does something much nearer to the
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304 | * posix 'cd -P' (not the posix default of 'cd -L').
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305 | * If 'cd' is changed to support -P/L then the default here
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306 | * needs to be revisited if the historic behaviour is to be kept.
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307 | */
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308 |
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309 | int
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310 | pwdcmd(int argc, char **argv)
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311 | {
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312 | int i;
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313 | char opt = 'L';
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314 |
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315 | while ((i = nextopt("LP")) != '\0')
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316 | opt = i;
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317 | if (*argptr)
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318 | error("unexpected argument");
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319 |
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320 | if (opt == 'L')
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321 | getpwd(0);
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322 | else
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323 | find_curdir(0);
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324 |
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325 | setvar("PWD", curdir, VEXPORT);
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326 | out1str(curdir);
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327 | out1c('\n');
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328 | return 0;
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329 | }
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330 |
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331 |
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332 |
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333 |
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334 | #define MAXPWD 256
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335 |
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336 | /*
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337 | * Find out what the current directory is. If we already know the current
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338 | * directory, this routine returns immediately.
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339 | */
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340 | void
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341 | getpwd(int noerror)
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342 | {
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343 | char *pwd;
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344 | struct stat stdot, stpwd;
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345 | static int first = 1;
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346 |
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347 | if (curdir)
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348 | return;
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349 |
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350 | if (first) {
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351 | first = 0;
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352 | pwd = getenv("PWD");
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353 | if (pwd && IS_ROOT(pwd) && stat(".", &stdot) != -1 &&
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354 | stat(pwd, &stpwd) != -1 &&
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355 | stdot.st_dev == stpwd.st_dev &&
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356 | stdot.st_ino == stpwd.st_ino) {
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357 | curdir = savestr(pwd);
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358 | return;
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359 | }
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360 | }
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361 |
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362 | find_curdir(noerror);
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363 |
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364 | return;
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365 | }
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366 |
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367 | STATIC void
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368 | find_curdir(int noerror)
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369 | {
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370 | int i;
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371 | char *pwd;
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372 |
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373 | /*
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374 | * Things are a bit complicated here; we could have just used
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375 | * getcwd, but traditionally getcwd is implemented using popen
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376 | * to /bin/pwd. This creates a problem for us, since we cannot
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377 | * keep track of the job if it is being ran behind our backs.
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378 | * So we re-implement getcwd(), and we suppress interrupts
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379 | * throughout the process. This is not completely safe, since
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380 | * the user can still break out of it by killing the pwd program.
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381 | * We still try to use getcwd for systems that we know have a
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382 | * c implementation of getcwd, that does not open a pipe to
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383 | * /bin/pwd.
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384 | */
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385 | #if defined(__NetBSD__) || defined(__SVR4) || defined(__INNOTEK_LIBC__)
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386 |
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387 | for (i = MAXPWD;; i *= 2) {
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388 | pwd = stalloc(i);
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389 | if (getcwd(pwd, i) != NULL) {
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390 | curdir = savestr(pwd);
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391 | return;
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392 | }
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393 | stunalloc(pwd);
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394 | if (errno == ERANGE)
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395 | continue;
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396 | if (!noerror)
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397 | error("getcwd() failed: %s", strerror(errno));
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398 | return;
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399 | }
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400 | #else
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401 | {
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402 | char *p;
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403 | int status;
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404 | struct job *jp;
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405 | int pip[2];
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406 |
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407 | pwd = stalloc(MAXPWD);
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408 | INTOFF;
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409 | if (pipe(pip) < 0)
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410 | error("Pipe call failed");
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411 | jp = makejob((union node *)NULL, 1);
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412 | if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) {
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413 | (void) close(pip[0]);
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414 | if (pip[1] != 1) {
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415 | close(1);
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416 | copyfd(pip[1], 1);
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417 | close(pip[1]);
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418 | }
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419 | (void) execl("/bin/pwd", "pwd", (char *)0);
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420 | error("Cannot exec /bin/pwd");
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421 | }
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422 | (void) close(pip[1]);
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423 | pip[1] = -1;
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424 | p = pwd;
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425 | while ((i = read(pip[0], p, pwd + MAXPWD - p)) > 0
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426 | || (i == -1 && errno == EINTR)) {
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427 | if (i > 0)
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428 | p += i;
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429 | }
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430 | (void) close(pip[0]);
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431 | pip[0] = -1;
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432 | status = waitforjob(jp);
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433 | if (status != 0)
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434 | error((char *)0);
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435 | if (i < 0 || p == pwd || p[-1] != '\n') {
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436 | if (noerror) {
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437 | INTON;
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438 | return;
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439 | }
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440 | error("pwd command failed");
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441 | }
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442 | p[-1] = '\0';
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443 | INTON;
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444 | curdir = savestr(pwd);
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445 | return;
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446 | }
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447 | #endif
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448 | }
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