cd.c revision 1.2
1 /*- 2 * Copyright (c) 1991 The Regents of the University of California. 3 * 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 * PATCHES MAGIC LEVEL PATCH THAT GOT US HERE 37 * -------------------- ----- ---------------------- 38 * CURRENT PATCH LEVEL: 1 00050 39 * -------------------- ----- ---------------------- 40 * 41 * 22 Aug 92 pk (?) Fix "pwd hang bug" 42 */ 43 44 #ifndef lint 45 static char sccsid[] = "@(#)cd.c 5.2 (Berkeley) 3/13/91"; 46 #endif /* not lint */ 47 48 /* 49 * The cd and pwd commands. 50 */ 51 52 #include "shell.h" 53 #include "var.h" 54 #include "nodes.h" /* for jobs.h */ 55 #include "jobs.h" 56 #include "options.h" 57 #include "output.h" 58 #include "memalloc.h" 59 #include "error.h" 60 #include "mystring.h" 61 #include <sys/types.h> 62 #include <sys/stat.h> 63 #include <errno.h> 64 65 66 #ifdef __STDC__ 67 STATIC int docd(char *, int); 68 STATIC void updatepwd(char *); 69 STATIC void getpwd(void); 70 STATIC char *getcomponent(void); 71 #else 72 STATIC int docd(); 73 STATIC void updatepwd(); 74 STATIC void getpwd(); 75 STATIC char *getcomponent(); 76 #endif 77 78 79 char *curdir; /* current working directory */ 80 STATIC char *cdcomppath; 81 82 #if UDIR 83 extern int didudir; /* set if /u/logname expanded */ 84 #endif 85 86 87 int 88 cdcmd(argc, argv) char **argv; { 89 char *dest; 90 char *path; 91 char *p; 92 struct stat statb; 93 char *padvance(); 94 95 nextopt(nullstr); 96 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 97 error("HOME not set"); 98 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 99 path = nullstr; 100 while ((p = padvance(&path, dest)) != NULL) { 101 if (stat(p, &statb) >= 0 102 && (statb.st_mode & S_IFMT) == S_IFDIR 103 && docd(p, strcmp(p, dest)) >= 0) 104 return 0; 105 } 106 error("can't cd to %s", dest); 107 } 108 109 110 /* 111 * Actually do the chdir. If the name refers to symbolic links, we 112 * compute the actual directory name before doing the cd. In an 113 * interactive shell, print the directory name if "print" is nonzero 114 * or if the name refers to a symbolic link. We also print the name 115 * if "/u/logname" was expanded in it, since this is similar to a 116 * symbolic link. (The check for this breaks if the user gives the 117 * cd command some additional, unused arguments.) 118 */ 119 120 #if SYMLINKS == 0 121 STATIC int 122 docd(dest, print) 123 char *dest; 124 { 125 #if UDIR 126 if (didudir) 127 print = 1; 128 #endif 129 INTOFF; 130 if (chdir(dest) < 0) { 131 INTON; 132 return -1; 133 } 134 updatepwd(dest); 135 INTON; 136 #ifdef not 137 if (print && iflag) 138 out1fmt("%s\n", stackblock()); 139 #endif 140 return 0; 141 } 142 143 #else 144 145 146 147 STATIC int 148 docd(dest, print) 149 char *dest; 150 { 151 register char *p; 152 register char *q; 153 char *symlink; 154 char *component; 155 struct stat statb; 156 int first; 157 int i; 158 159 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 160 #if UDIR 161 if (didudir) 162 print = 1; 163 #endif 164 165 top: 166 cdcomppath = dest; 167 STARTSTACKSTR(p); 168 if (*dest == '/') { 169 STPUTC('/', p); 170 cdcomppath++; 171 } 172 first = 1; 173 while ((q = getcomponent()) != NULL) { 174 if (q[0] == '\0' || q[0] == '.' && q[1] == '\0') 175 continue; 176 if (! first) 177 STPUTC('/', p); 178 first = 0; 179 component = q; 180 while (*q) 181 STPUTC(*q++, p); 182 if (equal(component, "..")) 183 continue; 184 STACKSTRNUL(p); 185 if (lstat(stackblock(), &statb) < 0) 186 error("lstat %s failed", stackblock()); 187 if ((statb.st_mode & S_IFMT) != S_IFLNK) 188 continue; 189 190 /* Hit a symbolic link. We have to start all over again. */ 191 print = 1; 192 STPUTC('\0', p); 193 symlink = grabstackstr(p); 194 i = (int)statb.st_size + 2; /* 2 for '/' and '\0' */ 195 if (cdcomppath != NULL) 196 i += strlen(cdcomppath); 197 p = stalloc(i); 198 if (readlink(symlink, p, (int)statb.st_size) < 0) { 199 error("readlink %s failed", stackblock()); 200 } 201 if (cdcomppath != NULL) { 202 p[(int)statb.st_size] = '/'; 203 scopy(cdcomppath, p + (int)statb.st_size + 1); 204 } else { 205 p[(int)statb.st_size] = '\0'; 206 } 207 if (p[0] != '/') { /* relative path name */ 208 char *r; 209 q = r = symlink; 210 while (*q) { 211 if (*q++ == '/') 212 r = q; 213 } 214 *r = '\0'; 215 dest = stalloc(strlen(symlink) + strlen(p) + 1); 216 scopy(symlink, dest); 217 strcat(dest, p); 218 } else { 219 dest = p; 220 } 221 goto top; 222 } 223 STPUTC('\0', p); 224 p = grabstackstr(p); 225 INTOFF; 226 if (chdir(p) < 0) { 227 INTON; 228 return -1; 229 } 230 updatepwd(p); 231 INTON; 232 #ifdef not 233 if (print && iflag) 234 out1fmt("%s\n", p); 235 #endif 236 return 0; 237 } 238 #endif /* SYMLINKS */ 239 240 241 242 /* 243 * Get the next component of the path name pointed to by cdcomppath. 244 * This routine overwrites the string pointed to by cdcomppath. 245 */ 246 247 STATIC char * 248 getcomponent() { 249 register char *p; 250 char *start; 251 252 if ((p = cdcomppath) == NULL) 253 return NULL; 254 start = cdcomppath; 255 while (*p != '/' && *p != '\0') 256 p++; 257 if (*p == '\0') { 258 cdcomppath = NULL; 259 } else { 260 *p++ = '\0'; 261 cdcomppath = p; 262 } 263 return start; 264 } 265 266 267 268 /* 269 * Update curdir (the name of the current directory) in response to a 270 * cd command. We also call hashcd to let the routines in exec.c know 271 * that the current directory has changed. 272 */ 273 274 void hashcd(); 275 276 STATIC void 277 updatepwd(dir) 278 char *dir; 279 { 280 char *new; 281 char *p; 282 283 hashcd(); /* update command hash table */ 284 cdcomppath = stalloc(strlen(dir) + 1); 285 scopy(dir, cdcomppath); 286 STARTSTACKSTR(new); 287 if (*dir != '/') { 288 if (curdir == NULL) 289 return; 290 p = curdir; 291 while (*p) 292 STPUTC(*p++, new); 293 if (p[-1] == '/') 294 STUNPUTC(new); 295 } 296 while ((p = getcomponent()) != NULL) { 297 if (equal(p, "..")) { 298 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 299 } else if (*p != '\0' && ! equal(p, ".")) { 300 STPUTC('/', new); 301 while (*p) 302 STPUTC(*p++, new); 303 } 304 } 305 if (new == stackblock()) 306 STPUTC('/', new); 307 STACKSTRNUL(new); 308 if (curdir) 309 ckfree(curdir); 310 curdir = savestr(stackblock()); 311 } 312 313 314 315 int 316 pwdcmd(argc, argv) char **argv; { 317 getpwd(); 318 out1str(curdir); 319 out1c('\n'); 320 return 0; 321 } 322 323 324 325 /* 326 * Run /bin/pwd to find out what the current directory is. We suppress 327 * interrupts throughout most of this, but the user can still break out 328 * of it by killing the pwd program. If we already know the current 329 * directory, this routine returns immediately. 330 */ 331 332 #define MAXPWD 256 333 334 STATIC void 335 getpwd() { 336 char buf[MAXPWD]; 337 char *p; 338 int i; 339 int status; 340 struct job *jp; 341 int pip[2]; 342 343 if (curdir) 344 return; 345 INTOFF; 346 if (pipe(pip) < 0) 347 error("Pipe call failed"); 348 jp = makejob((union node *)NULL, 1); 349 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 350 close(pip[0]); 351 if (pip[1] != 1) { 352 close(1); 353 copyfd(pip[1], 1); 354 close(pip[1]); 355 } 356 execl("/bin/pwd", "pwd", (char *)0); 357 /* error("Cannot exec /bin/pwd");*/ 358 out2str("Cannot exec /bin/pwd\n"); /* 22 Aug 92*/ 359 flushall(); 360 _exit(1); 361 } 362 close(pip[1]); 363 pip[1] = -1; 364 p = buf; 365 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 366 || i == -1 && errno == EINTR) { 367 if (i > 0) 368 p += i; 369 } 370 close(pip[0]); 371 pip[0] = -1; 372 status = waitforjob(jp); 373 if (status != 0) 374 error((char *)0); 375 if (i < 0 || p == buf || p[-1] != '\n') 376 error("pwd command failed"); 377 p[-1] = '\0'; 378 curdir = savestr(buf); 379 INTON; 380 } 381
Indexes created Thu Oct 23 18:09:57 GMT 2025