1 /*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
36 #endif
37 #endif /* not lint */
38 #include <sys/cdefs.h>
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <stdlib.h>
42 #include <string.h>
43 #include <unistd.h>
44 #include <errno.h>
45 #include <limits.h>
46
47 /*
48 * The cd and pwd commands.
49 */
50
51 #include "shell.h"
52 #include "var.h"
53 #include "nodes.h" /* for jobs.h */
54 #include "jobs.h"
55 #include "options.h"
56 #include "output.h"
57 #include "memalloc.h"
58 #include "error.h"
59 #include "exec.h"
60 #include "redir.h"
61 #include "mystring.h"
62 #include "show.h"
63 #include "cd.h"
64 #include "builtins.h"
65
66 static int cdlogical(char *);
67 static int cdphysical(char *);
68 static int docd(char *, int, int);
69 static char *getcomponent(char **);
70 static char *findcwd(char *);
71 static void updatepwd(char *);
72 static char *getpwd(void);
73 static char *getpwd2(void);
74
75 static char *curdir = NULL; /* current working directory */
76
77 int
cdcmd(int argc __unused,char ** argv __unused)78 cdcmd(int argc __unused, char **argv __unused)
79 {
80 const char *dest;
81 const char *path;
82 char *p;
83 struct stat statb;
84 int ch, phys, print = 0, getcwderr = 0;
85 int rc;
86 int errno1 = ENOENT;
87
88 phys = Pflag;
89 while ((ch = nextopt("eLP")) != '\0') {
90 switch (ch) {
91 case 'e':
92 getcwderr = 1;
93 break;
94 case 'L':
95 phys = 0;
96 break;
97 case 'P':
98 phys = 1;
99 break;
100 }
101 }
102
103 if (*argptr != NULL && argptr[1] != NULL)
104 error("too many arguments");
105
106 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
107 error("HOME not set");
108 if (*dest == '\0')
109 dest = ".";
110 if (dest[0] == '-' && dest[1] == '\0') {
111 dest = bltinlookup("OLDPWD", 1);
112 if (dest == NULL)
113 error("OLDPWD not set");
114 print = 1;
115 }
116 if (dest[0] == '/' ||
117 (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
118 (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
119 (path = bltinlookup("CDPATH", 1)) == NULL)
120 path = "";
121 while ((p = padvance(&path, NULL, dest)) != NULL) {
122 if (stat(p, &statb) < 0) {
123 if (errno != ENOENT)
124 errno1 = errno;
125 } else if (!S_ISDIR(statb.st_mode))
126 errno1 = ENOTDIR;
127 else {
128 if (!print) {
129 /*
130 * XXX - rethink
131 */
132 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
133 print = strcmp(p + 2, dest);
134 else
135 print = strcmp(p, dest);
136 }
137 rc = docd(p, print, phys);
138 if (rc >= 0)
139 return getcwderr ? rc : 0;
140 if (errno != ENOENT)
141 errno1 = errno;
142 }
143 }
144 error("%s: %s", dest, strerror(errno1));
145 /*NOTREACHED*/
146 return 0;
147 }
148
149
150 /*
151 * Actually change the directory. In an interactive shell, print the
152 * directory name if "print" is nonzero.
153 */
154 static int
docd(char * dest,int print,int phys)155 docd(char *dest, int print, int phys)
156 {
157 int rc;
158
159 TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
160
161 /* If logical cd fails, fall back to physical. */
162 if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
163 return (-1);
164
165 if (print && iflag && curdir) {
166 out1fmt("%s\n", curdir);
167 /*
168 * Ignore write errors to preserve the invariant that the
169 * current directory is changed iff the exit status is 0
170 * (or 1 if -e was given and the full pathname could not be
171 * determined).
172 */
173 flushout(out1);
174 outclearerror(out1);
175 }
176
177 return (rc);
178 }
179
180 static int
cdlogical(char * dest)181 cdlogical(char *dest)
182 {
183 char *p;
184 char *q;
185 char *component;
186 char *path;
187 struct stat statb;
188 int first;
189 int badstat;
190
191 /*
192 * Check each component of the path. If we find a symlink or
193 * something we can't stat, clear curdir to force a getcwd()
194 * next time we get the value of the current directory.
195 */
196 badstat = 0;
197 path = stsavestr(dest);
198 STARTSTACKSTR(p);
199 if (*dest == '/') {
200 STPUTC('/', p);
201 path++;
202 }
203 first = 1;
204 while ((q = getcomponent(&path)) != NULL) {
205 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
206 continue;
207 if (! first)
208 STPUTC('/', p);
209 first = 0;
210 component = q;
211 STPUTS(q, p);
212 if (equal(component, ".."))
213 continue;
214 STACKSTRNUL(p);
215 if (lstat(stackblock(), &statb) < 0) {
216 badstat = 1;
217 break;
218 }
219 }
220
221 INTOFF;
222 if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
223 INTON;
224 return (-1);
225 }
226 updatepwd(p);
227 INTON;
228 return (0);
229 }
230
231 static int
cdphysical(char * dest)232 cdphysical(char *dest)
233 {
234 char *p;
235 int rc = 0;
236
237 INTOFF;
238 if (chdir(dest) < 0) {
239 INTON;
240 return (-1);
241 }
242 p = findcwd(NULL);
243 if (p == NULL) {
244 warning("warning: failed to get name of current directory");
245 rc = 1;
246 }
247 updatepwd(p);
248 INTON;
249 return (rc);
250 }
251
252 /*
253 * Get the next component of the path name pointed to by *path.
254 * This routine overwrites *path and the string pointed to by it.
255 */
256 static char *
getcomponent(char ** path)257 getcomponent(char **path)
258 {
259 char *p;
260 char *start;
261
262 if ((p = *path) == NULL)
263 return NULL;
264 start = *path;
265 while (*p != '/' && *p != '\0')
266 p++;
267 if (*p == '\0') {
268 *path = NULL;
269 } else {
270 *p++ = '\0';
271 *path = p;
272 }
273 return start;
274 }
275
276
277 static char *
findcwd(char * dir)278 findcwd(char *dir)
279 {
280 char *new;
281 char *p;
282 char *path;
283
284 /*
285 * If our argument is NULL, we don't know the current directory
286 * any more because we traversed a symbolic link or something
287 * we couldn't stat().
288 */
289 if (dir == NULL || curdir == NULL)
290 return getpwd2();
291 path = stsavestr(dir);
292 STARTSTACKSTR(new);
293 if (*dir != '/') {
294 STPUTS(curdir, new);
295 if (STTOPC(new) == '/')
296 STUNPUTC(new);
297 }
298 while ((p = getcomponent(&path)) != NULL) {
299 if (equal(p, "..")) {
300 while (new > stackblock() && (STUNPUTC(new), *new) != '/');
301 } else if (*p != '\0' && ! equal(p, ".")) {
302 STPUTC('/', new);
303 STPUTS(p, new);
304 }
305 }
306 if (new == stackblock())
307 STPUTC('/', new);
308 STACKSTRNUL(new);
309 return stackblock();
310 }
311
312 /*
313 * Update curdir (the name of the current directory) in response to a
314 * cd command. We also call hashcd to let the routines in exec.c know
315 * that the current directory has changed.
316 */
317 static void
updatepwd(char * dir)318 updatepwd(char *dir)
319 {
320 char *prevdir;
321
322 hashcd(); /* update command hash table */
323
324 setvar("PWD", dir, VEXPORT);
325 setvar("OLDPWD", curdir, VEXPORT);
326 prevdir = curdir;
327 curdir = dir ? savestr(dir) : NULL;
328 ckfree(prevdir);
329 }
330
331 int
pwdcmd(int argc __unused,char ** argv __unused)332 pwdcmd(int argc __unused, char **argv __unused)
333 {
334 char *p;
335 int ch, phys;
336
337 phys = Pflag;
338 while ((ch = nextopt("LP")) != '\0') {
339 switch (ch) {
340 case 'L':
341 phys = 0;
342 break;
343 case 'P':
344 phys = 1;
345 break;
346 }
347 }
348
349 if (*argptr != NULL)
350 error("too many arguments");
351
352 if (!phys && getpwd()) {
353 out1str(curdir);
354 out1c('\n');
355 } else {
356 if ((p = getpwd2()) == NULL)
357 error(".: %s", strerror(errno));
358 out1str(p);
359 out1c('\n');
360 }
361
362 return 0;
363 }
364
365 /*
366 * Get the current directory and cache the result in curdir.
367 */
368 static char *
getpwd(void)369 getpwd(void)
370 {
371 char *p;
372
373 if (curdir)
374 return curdir;
375
376 p = getpwd2();
377 if (p != NULL) {
378 INTOFF;
379 curdir = savestr(p);
380 INTON;
381 }
382
383 return curdir;
384 }
385
386 #define MAXPWD 256
387
388 /*
389 * Return the current directory.
390 */
391 static char *
getpwd2(void)392 getpwd2(void)
393 {
394 char *pwd;
395 int i;
396
397 for (i = MAXPWD;; i *= 2) {
398 pwd = stalloc(i);
399 if (getcwd(pwd, i) != NULL)
400 return pwd;
401 stunalloc(pwd);
402 if (errno != ERANGE)
403 break;
404 }
405
406 return NULL;
407 }
408
409 /*
410 * Initialize PWD in a new shell.
411 * If the shell is interactive, we need to warn if this fails.
412 */
413 void
pwd_init(int warn)414 pwd_init(int warn)
415 {
416 char *pwd;
417 struct stat stdot, stpwd;
418
419 pwd = lookupvar("PWD");
420 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
421 stat(pwd, &stpwd) != -1 &&
422 stdot.st_dev == stpwd.st_dev &&
423 stdot.st_ino == stpwd.st_ino) {
424 if (curdir)
425 ckfree(curdir);
426 curdir = savestr(pwd);
427 }
428 if (getpwd() == NULL && warn)
429 out2fmt_flush("sh: cannot determine working directory\n");
430 setvar("PWD", curdir, VEXPORT);
431 }
432