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 * %sccs.include.redist.c% 9 */ 10 11 #ifndef lint 12 static char sccsid[] = "@(#)cd.c 5.2 (Berkeley) 03/13/91"; 13 #endif /* not lint */ 14 15 /* 16 * The cd and pwd commands. 17 */ 18 19 #include "shell.h" 20 #include "var.h" 21 #include "nodes.h" /* for jobs.h */ 22 #include "jobs.h" 23 #include "options.h" 24 #include "output.h" 25 #include "memalloc.h" 26 #include "error.h" 27 #include "mystring.h" 28 #include <sys/types.h> 29 #include <sys/stat.h> 30 #include <errno.h> 31 32 33 #ifdef __STDC__ 34 STATIC int docd(char *, int); 35 STATIC void updatepwd(char *); 36 STATIC void getpwd(void); 37 STATIC char *getcomponent(void); 38 #else 39 STATIC int docd(); 40 STATIC void updatepwd(); 41 STATIC void getpwd(); 42 STATIC char *getcomponent(); 43 #endif 44 45 46 char *curdir; /* current working directory */ 47 STATIC char *cdcomppath; 48 49 #if UDIR 50 extern int didudir; /* set if /u/logname expanded */ 51 #endif 52 53 54 int 55 cdcmd(argc, argv) char **argv; { 56 char *dest; 57 char *path; 58 char *p; 59 struct stat statb; 60 char *padvance(); 61 62 nextopt(nullstr); 63 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 64 error("HOME not set"); 65 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 66 path = nullstr; 67 while ((p = padvance(&path, dest)) != NULL) { 68 if (stat(p, &statb) >= 0 69 && (statb.st_mode & S_IFMT) == S_IFDIR 70 && docd(p, strcmp(p, dest)) >= 0) 71 return 0; 72 } 73 error("can't cd to %s", dest); 74 } 75 76 77 /* 78 * Actually do the chdir. If the name refers to symbolic links, we 79 * compute the actual directory name before doing the cd. In an 80 * interactive shell, print the directory name if "print" is nonzero 81 * or if the name refers to a symbolic link. We also print the name 82 * if "/u/logname" was expanded in it, since this is similar to a 83 * symbolic link. (The check for this breaks if the user gives the 84 * cd command some additional, unused arguments.) 85 */ 86 87 #if SYMLINKS == 0 88 STATIC int 89 docd(dest, print) 90 char *dest; 91 { 92 #if UDIR 93 if (didudir) 94 print = 1; 95 #endif 96 INTOFF; 97 if (chdir(dest) < 0) { 98 INTON; 99 return -1; 100 } 101 updatepwd(dest); 102 INTON; 103 if (print && iflag) 104 out1fmt("%s\n", stackblock()); 105 return 0; 106 } 107 108 #else 109 110 111 112 STATIC int 113 docd(dest, print) 114 char *dest; 115 { 116 register char *p; 117 register char *q; 118 char *symlink; 119 char *component; 120 struct stat statb; 121 int first; 122 int i; 123 124 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 125 #if UDIR 126 if (didudir) 127 print = 1; 128 #endif 129 130 top: 131 cdcomppath = dest; 132 STARTSTACKSTR(p); 133 if (*dest == '/') { 134 STPUTC('/', p); 135 cdcomppath++; 136 } 137 first = 1; 138 while ((q = getcomponent()) != NULL) { 139 if (q[0] == '\0' || q[0] == '.' && q[1] == '\0') 140 continue; 141 if (! first) 142 STPUTC('/', p); 143 first = 0; 144 component = q; 145 while (*q) 146 STPUTC(*q++, p); 147 if (equal(component, "..")) 148 continue; 149 STACKSTRNUL(p); 150 if (lstat(stackblock(), &statb) < 0) 151 error("lstat %s failed", stackblock()); 152 if ((statb.st_mode & S_IFMT) != S_IFLNK) 153 continue; 154 155 /* Hit a symbolic link. We have to start all over again. */ 156 print = 1; 157 STPUTC('\0', p); 158 symlink = grabstackstr(p); 159 i = (int)statb.st_size + 2; /* 2 for '/' and '\0' */ 160 if (cdcomppath != NULL) 161 i += strlen(cdcomppath); 162 p = stalloc(i); 163 if (readlink(symlink, p, (int)statb.st_size) < 0) { 164 error("readlink %s failed", stackblock()); 165 } 166 if (cdcomppath != NULL) { 167 p[(int)statb.st_size] = '/'; 168 scopy(cdcomppath, p + (int)statb.st_size + 1); 169 } else { 170 p[(int)statb.st_size] = '\0'; 171 } 172 if (p[0] != '/') { /* relative path name */ 173 char *r; 174 q = r = symlink; 175 while (*q) { 176 if (*q++ == '/') 177 r = q; 178 } 179 *r = '\0'; 180 dest = stalloc(strlen(symlink) + strlen(p) + 1); 181 scopy(symlink, dest); 182 strcat(dest, p); 183 } else { 184 dest = p; 185 } 186 goto top; 187 } 188 STPUTC('\0', p); 189 p = grabstackstr(p); 190 INTOFF; 191 if (chdir(p) < 0) { 192 INTON; 193 return -1; 194 } 195 updatepwd(p); 196 INTON; 197 if (print && iflag) 198 out1fmt("%s\n", p); 199 return 0; 200 } 201 #endif /* SYMLINKS */ 202 203 204 205 /* 206 * Get the next component of the path name pointed to by cdcomppath. 207 * This routine overwrites the string pointed to by cdcomppath. 208 */ 209 210 STATIC char * 211 getcomponent() { 212 register char *p; 213 char *start; 214 215 if ((p = cdcomppath) == NULL) 216 return NULL; 217 start = cdcomppath; 218 while (*p != '/' && *p != '\0') 219 p++; 220 if (*p == '\0') { 221 cdcomppath = NULL; 222 } else { 223 *p++ = '\0'; 224 cdcomppath = p; 225 } 226 return start; 227 } 228 229 230 231 /* 232 * Update curdir (the name of the current directory) in response to a 233 * cd command. We also call hashcd to let the routines in exec.c know 234 * that the current directory has changed. 235 */ 236 237 void hashcd(); 238 239 STATIC void 240 updatepwd(dir) 241 char *dir; 242 { 243 char *new; 244 char *p; 245 246 hashcd(); /* update command hash table */ 247 cdcomppath = stalloc(strlen(dir) + 1); 248 scopy(dir, cdcomppath); 249 STARTSTACKSTR(new); 250 if (*dir != '/') { 251 if (curdir == NULL) 252 return; 253 p = curdir; 254 while (*p) 255 STPUTC(*p++, new); 256 if (p[-1] == '/') 257 STUNPUTC(new); 258 } 259 while ((p = getcomponent()) != NULL) { 260 if (equal(p, "..")) { 261 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 262 } else if (*p != '\0' && ! equal(p, ".")) { 263 STPUTC('/', new); 264 while (*p) 265 STPUTC(*p++, new); 266 } 267 } 268 if (new == stackblock()) 269 STPUTC('/', new); 270 STACKSTRNUL(new); 271 if (curdir) 272 ckfree(curdir); 273 curdir = savestr(stackblock()); 274 } 275 276 277 278 int 279 pwdcmd(argc, argv) char **argv; { 280 getpwd(); 281 out1str(curdir); 282 out1c('\n'); 283 return 0; 284 } 285 286 287 288 /* 289 * Run /bin/pwd to find out what the current directory is. We suppress 290 * interrupts throughout most of this, but the user can still break out 291 * of it by killing the pwd program. If we already know the current 292 * directory, this routine returns immediately. 293 */ 294 295 #define MAXPWD 256 296 297 STATIC void 298 getpwd() { 299 char buf[MAXPWD]; 300 char *p; 301 int i; 302 int status; 303 struct job *jp; 304 int pip[2]; 305 306 if (curdir) 307 return; 308 INTOFF; 309 if (pipe(pip) < 0) 310 error("Pipe call failed"); 311 jp = makejob((union node *)NULL, 1); 312 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 313 close(pip[0]); 314 if (pip[1] != 1) { 315 close(1); 316 copyfd(pip[1], 1); 317 close(pip[1]); 318 } 319 execl("/bin/pwd", "pwd", (char *)0); 320 error("Cannot exec /bin/pwd"); 321 } 322 close(pip[1]); 323 pip[1] = -1; 324 p = buf; 325 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 326 || i == -1 && errno == EINTR) { 327 if (i > 0) 328 p += i; 329 } 330 close(pip[0]); 331 pip[0] = -1; 332 status = waitforjob(jp); 333 if (status != 0) 334 error((char *)0); 335 if (i < 0 || p == buf || p[-1] != '\n') 336 error("pwd command failed"); 337 p[-1] = '\0'; 338 curdir = savestr(buf); 339 INTON; 340 } 341