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 __FBSDID("$FreeBSD: head/bin/sh/cd.c 356251 2020-01-01 12:06:37Z jilles $");
40
41 #include <sys/types.h>
42 #include <sys/stat.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <errno.h>
47 #include <limits.h>
48
49 /*
50 * The cd and pwd commands.
51 */
52
53 #include "shell.h"
54 #include "var.h"
55 #include "nodes.h" /* for jobs.h */
56 #include "jobs.h"
57 #include "options.h"
58 #include "output.h"
59 #include "memalloc.h"
60 #include "error.h"
61 #include "exec.h"
62 #include "redir.h"
63 #include "mystring.h"
64 #include "show.h"
65 #include "cd.h"
66 #include "builtins.h"
67
68 static int cdlogical(char *);
69 static int cdphysical(char *);
70 static int docd(char *, int, int);
71 static char *getcomponent(char **);
72 static char *findcwd(char *);
73 static void updatepwd(char *);
74 static char *getpwd(void);
75 static char *getpwd2(void);
76
77 static char *curdir = NULL; /* current working directory */
78
79 int
cdcmd(int argc __unused,char ** argv __unused)80 cdcmd(int argc __unused, char **argv __unused)
81 {
82 const char *dest;
83 const char *path;
84 char *p;
85 struct stat statb;
86 int ch, phys, print = 0, getcwderr = 0;
87 int rc;
88 int errno1 = ENOENT;
89
90 phys = Pflag;
91 while ((ch = nextopt("eLP")) != '\0') {
92 switch (ch) {
93 case 'e':
94 getcwderr = 1;
95 break;
96 case 'L':
97 phys = 0;
98 break;
99 case 'P':
100 phys = 1;
101 break;
102 }
103 }
104
105 if (*argptr != NULL && argptr[1] != NULL)
106 error("too many arguments");
107
108 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
109 error("HOME not set");
110 if (*dest == '\0')
111 dest = ".";
112 if (dest[0] == '-' && dest[1] == '\0') {
113 dest = bltinlookup("OLDPWD", 1);
114 if (dest == NULL)
115 error("OLDPWD not set");
116 print = 1;
117 }
118 if (dest[0] == '/' ||
119 (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
120 (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
121 (path = bltinlookup("CDPATH", 1)) == NULL)
122 path = "";
123 while ((p = padvance(&path, NULL, dest)) != NULL) {
124 if (stat(p, &statb) < 0) {
125 if (errno != ENOENT)
126 errno1 = errno;
127 } else if (!S_ISDIR(statb.st_mode))
128 errno1 = ENOTDIR;
129 else {
130 if (!print) {
131 /*
132 * XXX - rethink
133 */
134 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
135 print = strcmp(p + 2, dest);
136 else
137 print = strcmp(p, dest);
138 }
139 rc = docd(p, print, phys);
140 if (rc >= 0)
141 return getcwderr ? rc : 0;
142 if (errno != ENOENT)
143 errno1 = errno;
144 }
145 }
146 error("%s: %s", dest, strerror(errno1));
147 /*NOTREACHED*/
148 return 0;
149 }
150
151
152 /*
153 * Actually change the directory. In an interactive shell, print the
154 * directory name if "print" is nonzero.
155 */
156 static int
docd(char * dest,int print,int phys)157 docd(char *dest, int print, int phys)
158 {
159 int rc;
160
161 TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
162
163 /* If logical cd fails, fall back to physical. */
164 if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
165 return (-1);
166
167 if (print && iflag && curdir) {
168 out1fmt("%s\n", curdir);
169 /*
170 * Ignore write errors to preserve the invariant that the
171 * current directory is changed iff the exit status is 0
172 * (or 1 if -e was given and the full pathname could not be
173 * determined).
174 */
175 flushout(out1);
176 outclearerror(out1);
177 }
178
179 return (rc);
180 }
181
182 static int
cdlogical(char * dest)183 cdlogical(char *dest)
184 {
185 char *p;
186 char *q;
187 char *component;
188 char *path;
189 struct stat statb;
190 int first;
191 int badstat;
192
193 /*
194 * Check each component of the path. If we find a symlink or
195 * something we can't stat, clear curdir to force a getcwd()
196 * next time we get the value of the current directory.
197 */
198 badstat = 0;
199 path = stsavestr(dest);
200 STARTSTACKSTR(p);
201 if (*dest == '/') {
202 STPUTC('/', p);
203 path++;
204 }
205 first = 1;
206 while ((q = getcomponent(&path)) != NULL) {
207 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
208 continue;
209 if (! first)
210 STPUTC('/', p);
211 first = 0;
212 component = q;
213 STPUTS(q, p);
214 if (equal(component, ".."))
215 continue;
216 STACKSTRNUL(p);
217 if (lstat(stackblock(), &statb) < 0) {
218 badstat = 1;
219 break;
220 }
221 }
222
223 INTOFF;
224 if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
225 INTON;
226 return (-1);
227 }
228 updatepwd(p);
229 INTON;
230 return (0);
231 }
232
233 static int
cdphysical(char * dest)234 cdphysical(char *dest)
235 {
236 char *p;
237 int rc = 0;
238
239 INTOFF;
240 if (chdir(dest) < 0) {
241 INTON;
242 return (-1);
243 }
244 p = findcwd(NULL);
245 if (p == NULL) {
246 warning("warning: failed to get name of current directory");
247 rc = 1;
248 }
249 updatepwd(p);
250 INTON;
251 return (rc);
252 }
253
254 /*
255 * Get the next component of the path name pointed to by *path.
256 * This routine overwrites *path and the string pointed to by it.
257 */
258 static char *
getcomponent(char ** path)259 getcomponent(char **path)
260 {
261 char *p;
262 char *start;
263
264 if ((p = *path) == NULL)
265 return NULL;
266 start = *path;
267 while (*p != '/' && *p != '\0')
268 p++;
269 if (*p == '\0') {
270 *path = NULL;
271 } else {
272 *p++ = '\0';
273 *path = p;
274 }
275 return start;
276 }
277
278
279 static char *
findcwd(char * dir)280 findcwd(char *dir)
281 {
282 char *new;
283 char *p;
284 char *path;
285
286 /*
287 * If our argument is NULL, we don't know the current directory
288 * any more because we traversed a symbolic link or something
289 * we couldn't stat().
290 */
291 if (dir == NULL || curdir == NULL)
292 return getpwd2();
293 path = stsavestr(dir);
294 STARTSTACKSTR(new);
295 if (*dir != '/') {
296 STPUTS(curdir, new);
297 if (STTOPC(new) == '/')
298 STUNPUTC(new);
299 }
300 while ((p = getcomponent(&path)) != NULL) {
301 if (equal(p, "..")) {
302 while (new > stackblock() && (STUNPUTC(new), *new) != '/');
303 } else if (*p != '\0' && ! equal(p, ".")) {
304 STPUTC('/', new);
305 STPUTS(p, new);
306 }
307 }
308 if (new == stackblock())
309 STPUTC('/', new);
310 STACKSTRNUL(new);
311 return stackblock();
312 }
313
314 /*
315 * Update curdir (the name of the current directory) in response to a
316 * cd command. We also call hashcd to let the routines in exec.c know
317 * that the current directory has changed.
318 */
319 static void
updatepwd(char * dir)320 updatepwd(char *dir)
321 {
322 char *prevdir;
323
324 hashcd(); /* update command hash table */
325
326 setvar("PWD", dir, VEXPORT);
327 setvar("OLDPWD", curdir, VEXPORT);
328 prevdir = curdir;
329 curdir = dir ? savestr(dir) : NULL;
330 ckfree(prevdir);
331 }
332
333 int
pwdcmd(int argc __unused,char ** argv __unused)334 pwdcmd(int argc __unused, char **argv __unused)
335 {
336 char *p;
337 int ch, phys;
338
339 phys = Pflag;
340 while ((ch = nextopt("LP")) != '\0') {
341 switch (ch) {
342 case 'L':
343 phys = 0;
344 break;
345 case 'P':
346 phys = 1;
347 break;
348 }
349 }
350
351 if (*argptr != NULL)
352 error("too many arguments");
353
354 if (!phys && getpwd()) {
355 out1str(curdir);
356 out1c('\n');
357 } else {
358 if ((p = getpwd2()) == NULL)
359 error(".: %s", strerror(errno));
360 out1str(p);
361 out1c('\n');
362 }
363
364 return 0;
365 }
366
367 /*
368 * Get the current directory and cache the result in curdir.
369 */
370 static char *
getpwd(void)371 getpwd(void)
372 {
373 char *p;
374
375 if (curdir)
376 return curdir;
377
378 p = getpwd2();
379 if (p != NULL) {
380 INTOFF;
381 curdir = savestr(p);
382 INTON;
383 }
384
385 return curdir;
386 }
387
388 #define MAXPWD 256
389
390 /*
391 * Return the current directory.
392 */
393 static char *
getpwd2(void)394 getpwd2(void)
395 {
396 char *pwd;
397 int i;
398
399 for (i = MAXPWD;; i *= 2) {
400 pwd = stalloc(i);
401 if (getcwd(pwd, i) != NULL)
402 return pwd;
403 stunalloc(pwd);
404 if (errno != ERANGE)
405 break;
406 }
407
408 return NULL;
409 }
410
411 /*
412 * Initialize PWD in a new shell.
413 * If the shell is interactive, we need to warn if this fails.
414 */
415 void
pwd_init(int warn)416 pwd_init(int warn)
417 {
418 char *pwd;
419 struct stat stdot, stpwd;
420
421 pwd = lookupvar("PWD");
422 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
423 stat(pwd, &stpwd) != -1 &&
424 stdot.st_dev == stpwd.st_dev &&
425 stdot.st_ino == stpwd.st_ino) {
426 if (curdir)
427 ckfree(curdir);
428 curdir = savestr(pwd);
429 }
430 if (getpwd() == NULL && warn)
431 out2fmt_flush("sh: cannot determine working directory\n");
432 setvar("PWD", curdir, VEXPORT);
433 }
434