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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <errno.h> 51 52 /* 53 * The cd and pwd commands. 54 */ 55 56 #include "shell.h" 57 #include "var.h" 58 #include "nodes.h" /* for jobs.h */ 59 #include "jobs.h" 60 #include "options.h" 61 #include "output.h" 62 #include "memalloc.h" 63 #include "error.h" 64 #include "exec.h" 65 #include "redir.h" 66 #include "mystring.h" 67 #include "show.h" 68 #include "cd.h" 69 70 STATIC int docd(char *, int); 71 STATIC char *getcomponent(void); 72 STATIC void updatepwd(char *); 73 74 char *curdir = NULL; /* current working directory */ 75 char *prevdir; /* previous working directory */ 76 STATIC char *cdcomppath; 77 78 int 79 cdcmd(int argc __unused, char **argv __unused) 80 { 81 char *dest; 82 char *path; 83 char *p; 84 struct stat statb; 85 int print = 0; 86 87 nextopt(nullstr); 88 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 89 error("HOME not set"); 90 if (*dest == '\0') 91 dest = "."; 92 if (dest[0] == '-' && dest[1] == '\0') { 93 dest = prevdir ? prevdir : curdir; 94 if (dest) 95 print = 1; 96 else 97 dest = "."; 98 } 99 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 100 path = nullstr; 101 while ((p = padvance(&path, dest)) != NULL) { 102 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) { 103 if (!print) { 104 /* 105 * XXX - rethink 106 */ 107 if (p[0] == '.' && p[1] == '/' && p[2] != '\0') 108 p += 2; 109 print = strcmp(p, dest); 110 } 111 if (docd(p, print) >= 0) 112 return 0; 113 114 } 115 } 116 error("can't cd to %s", dest); 117 /*NOTREACHED*/ 118 return 0; 119 } 120 121 122 /* 123 * Actually do the chdir. In an interactive shell, print the 124 * directory name if "print" is nonzero. 125 */ 126 STATIC int 127 docd(char *dest, int print) 128 { 129 char *p; 130 char *q; 131 char *component; 132 struct stat statb; 133 int first; 134 int badstat; 135 136 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 137 138 /* 139 * Check each component of the path. If we find a symlink or 140 * something we can't stat, clear curdir to force a getcwd() 141 * next time we get the value of the current directory. 142 */ 143 badstat = 0; 144 cdcomppath = stalloc(strlen(dest) + 1); 145 scopy(dest, cdcomppath); 146 STARTSTACKSTR(p); 147 if (*dest == '/') { 148 STPUTC('/', p); 149 cdcomppath++; 150 } 151 first = 1; 152 while ((q = getcomponent()) != NULL) { 153 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0')) 154 continue; 155 if (! first) 156 STPUTC('/', p); 157 first = 0; 158 component = q; 159 while (*q) 160 STPUTC(*q++, p); 161 if (equal(component, "..")) 162 continue; 163 STACKSTRNUL(p); 164 if ((lstat(stackblock(), &statb) < 0) 165 || (S_ISLNK(statb.st_mode))) { 166 /* print = 1; */ 167 badstat = 1; 168 break; 169 } 170 } 171 172 INTOFF; 173 if (chdir(dest) < 0) { 174 INTON; 175 return -1; 176 } 177 updatepwd(badstat ? NULL : dest); 178 INTON; 179 if (print && iflag && curdir) 180 out1fmt("%s\n", curdir); 181 return 0; 182 } 183 184 185 /* 186 * Get the next component of the path name pointed to by cdcomppath. 187 * This routine overwrites the string pointed to by cdcomppath. 188 */ 189 STATIC char * 190 getcomponent(void) 191 { 192 char *p; 193 char *start; 194 195 if ((p = cdcomppath) == NULL) 196 return NULL; 197 start = cdcomppath; 198 while (*p != '/' && *p != '\0') 199 p++; 200 if (*p == '\0') { 201 cdcomppath = NULL; 202 } else { 203 *p++ = '\0'; 204 cdcomppath = p; 205 } 206 return start; 207 } 208 209 210 /* 211 * Update curdir (the name of the current directory) in response to a 212 * cd command. We also call hashcd to let the routines in exec.c know 213 * that the current directory has changed. 214 */ 215 STATIC void 216 updatepwd(char *dir) 217 { 218 char *new; 219 char *p; 220 221 hashcd(); /* update command hash table */ 222 223 /* 224 * If our argument is NULL, we don't know the current directory 225 * any more because we traversed a symbolic link or something 226 * we couldn't stat(). 227 */ 228 if (dir == NULL || curdir == NULL) { 229 if (prevdir) 230 ckfree(prevdir); 231 INTOFF; 232 prevdir = curdir; 233 curdir = NULL; 234 if (getpwd() == NULL) 235 error("getcwd() failed: %s", strerror(errno)); 236 setvar("PWD", curdir, VEXPORT); 237 setvar("OLDPWD", prevdir, VEXPORT); 238 INTON; 239 return; 240 } 241 cdcomppath = stalloc(strlen(dir) + 1); 242 scopy(dir, cdcomppath); 243 STARTSTACKSTR(new); 244 if (*dir != '/') { 245 p = curdir; 246 while (*p) 247 STPUTC(*p++, new); 248 if (p[-1] == '/') 249 STUNPUTC(new); 250 } 251 while ((p = getcomponent()) != NULL) { 252 if (equal(p, "..")) { 253 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 254 } else if (*p != '\0' && ! equal(p, ".")) { 255 STPUTC('/', new); 256 while (*p) 257 STPUTC(*p++, new); 258 } 259 } 260 if (new == stackblock()) 261 STPUTC('/', new); 262 STACKSTRNUL(new); 263 INTOFF; 264 if (prevdir) 265 ckfree(prevdir); 266 prevdir = curdir; 267 curdir = savestr(stackblock()); 268 setvar("PWD", curdir, VEXPORT); 269 setvar("OLDPWD", prevdir, VEXPORT); 270 INTON; 271 } 272 273 274 int 275 pwdcmd(int argc __unused, char **argv __unused) 276 { 277 if (!getpwd()) 278 error("getcwd() failed: %s", strerror(errno)); 279 out1str(curdir); 280 out1c('\n'); 281 return 0; 282 } 283 284 285 286 287 #define MAXPWD 256 288 289 /* 290 * Find out what the current directory is. If we already know the current 291 * directory, this routine returns immediately. 292 */ 293 char * 294 getpwd(void) 295 { 296 char buf[MAXPWD]; 297 298 if (curdir) 299 return curdir; 300 /* 301 * Things are a bit complicated here; we could have just used 302 * getcwd, but traditionally getcwd is implemented using popen 303 * to /bin/pwd. This creates a problem for us, since we cannot 304 * keep track of the job if it is being ran behind our backs. 305 * So we re-implement getcwd(), and we suppress interrupts 306 * throughout the process. This is not completely safe, since 307 * the user can still break out of it by killing the pwd program. 308 * We still try to use getcwd for systems that we know have a 309 * c implementation of getcwd, that does not open a pipe to 310 * /bin/pwd. 311 */ 312 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__SVR4) 313 314 if (getcwd(buf, sizeof(buf)) == NULL) { 315 char *pwd = getenv("PWD"); 316 struct stat stdot, stpwd; 317 318 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 && 319 stat(pwd, &stpwd) != -1 && 320 stdot.st_dev == stpwd.st_dev && 321 stdot.st_ino == stpwd.st_ino) { 322 curdir = savestr(pwd); 323 return curdir; 324 } 325 return NULL; 326 } 327 curdir = savestr(buf); 328 #else 329 { 330 char *p; 331 int i; 332 int status; 333 struct job *jp; 334 int pip[2]; 335 336 INTOFF; 337 if (pipe(pip) < 0) 338 error("Pipe call failed: %s", strerror(errno)); 339 jp = makejob((union node *)NULL, 1); 340 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 341 (void) close(pip[0]); 342 if (pip[1] != 1) { 343 close(1); 344 copyfd(pip[1], 1); 345 close(pip[1]); 346 } 347 (void) execl("/bin/pwd", "pwd", (char *)0); 348 error("Cannot exec /bin/pwd"); 349 } 350 (void) close(pip[1]); 351 pip[1] = -1; 352 p = buf; 353 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 354 || (i == -1 && errno == EINTR)) { 355 if (i > 0) 356 p += i; 357 } 358 (void) close(pip[0]); 359 pip[0] = -1; 360 status = waitforjob(jp); 361 if (status != 0) 362 error((char *)0); 363 if (i < 0 || p == buf || p[-1] != '\n') 364 error("pwd command failed"); 365 p[-1] = '\0'; 366 } 367 curdir = savestr(buf); 368 INTON; 369 #endif 370 return curdir; 371 } 372