1 /* 2 * Copyright (c) 1989, 1991, 1993, 1995 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 */ 33 34 #if defined(LIBC_SCCS) && !defined(lint) 35 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; 36 #endif /* LIBC_SCCS and not lint */ 37 38 #include <sys/param.h> 39 #include <sys/stat.h> 40 41 #include <dirent.h> 42 #include <errno.h> 43 #include <fcntl.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <unistd.h> 48 #include <signal.h> 49 50 #define ISDOT(dp) \ 51 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 52 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 53 54 static int have__getcwd = 1; /* 0 = no, 1 = perhaps, 2 = yes */ 55 56 char * 57 getcwd(pt, size) 58 char *pt; 59 size_t size; 60 { 61 register struct dirent *dp; 62 register DIR *dir = NULL; 63 register dev_t dev; 64 register ino_t ino; 65 register int first; 66 register char *bpt, *bup; 67 struct stat s; 68 dev_t root_dev; 69 ino_t root_ino; 70 size_t ptsize, upsize; 71 int save_errno; 72 char *ept, *eup, *up, c; 73 74 /* 75 * If no buffer specified by the user, allocate one as necessary. 76 * If a buffer is specified, the size has to be non-zero. The path 77 * is built from the end of the buffer backwards. 78 */ 79 if (pt) { 80 ptsize = 0; 81 if (!size) { 82 errno = EINVAL; 83 return (NULL); 84 } 85 if (size == 1) { 86 errno = ERANGE; 87 return (NULL); 88 } 89 ept = pt + size; 90 } else { 91 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 92 return (NULL); 93 ept = pt + ptsize; 94 } 95 #if defined(__NETBSD_SYSCALLS) 96 have__getcwd = 0; 97 #else 98 if (have__getcwd) { 99 struct sigaction sa, osa; 100 int sigsys_installed = 0; 101 int ret; 102 103 if (have__getcwd == 1) { /* unsure? */ 104 bzero(&sa, sizeof(sa)); 105 sa.sa_handler = SIG_IGN; 106 if (sigaction(SIGSYS, &sa, &osa) >= 0) 107 sigsys_installed = 1; 108 } 109 ret = __getcwd(pt, ept - pt); 110 if (sigsys_installed == 1) { 111 int oerrno = errno; 112 sigaction(SIGSYS, &osa, NULL); 113 errno = oerrno; 114 } 115 /* XXX a bogus syscall seems to return EINVAL(!) */ 116 if (ret < 0 && (errno == ENOSYS || errno == EINVAL)) 117 have__getcwd = 0; 118 else if (have__getcwd == 1) 119 have__getcwd = 2; /* yep, remember we have it */ 120 if (ret == 0) { 121 if (*pt != '/') { 122 bpt = pt; 123 ept = pt + strlen(pt) - 1; 124 while (bpt < ept) { 125 c = *bpt; 126 *bpt++ = *ept; 127 *ept-- = c; 128 } 129 } 130 return (pt); 131 } 132 } 133 #endif 134 bpt = ept - 1; 135 *bpt = '\0'; 136 137 /* 138 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 139 * Should always be enough (it's 340 levels). If it's not, allocate 140 * as necessary. Special case the first stat, it's ".", not "..". 141 */ 142 if ((up = malloc(upsize = 1024 - 4)) == NULL) 143 goto err; 144 eup = up + MAXPATHLEN; 145 bup = up; 146 up[0] = '.'; 147 up[1] = '\0'; 148 149 /* Save root values, so know when to stop. */ 150 if (stat("/", &s)) 151 goto err; 152 root_dev = s.st_dev; 153 root_ino = s.st_ino; 154 155 errno = 0; /* XXX readdir has no error return. */ 156 157 for (first = 1;; first = 0) { 158 /* Stat the current level. */ 159 if (lstat(up, &s)) 160 goto err; 161 162 /* Save current node values. */ 163 ino = s.st_ino; 164 dev = s.st_dev; 165 166 /* Check for reaching root. */ 167 if (root_dev == dev && root_ino == ino) { 168 *--bpt = '/'; 169 /* 170 * It's unclear that it's a requirement to copy the 171 * path to the beginning of the buffer, but it's always 172 * been that way and stuff would probably break. 173 */ 174 bcopy(bpt, pt, ept - bpt); 175 free(up); 176 return (pt); 177 } 178 179 /* 180 * Build pointer to the parent directory, allocating memory 181 * as necessary. Max length is 3 for "../", the largest 182 * possible component name, plus a trailing NULL. 183 */ 184 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 185 if ((up = reallocf(up, upsize *= 2)) == NULL) 186 goto err; 187 bup = up; 188 eup = up + upsize; 189 } 190 *bup++ = '.'; 191 *bup++ = '.'; 192 *bup = '\0'; 193 194 /* Open and stat parent directory. */ 195 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) 196 goto err; 197 198 /* Add trailing slash for next directory. */ 199 *bup++ = '/'; 200 *bup = '\0'; 201 202 /* 203 * If it's a mount point, have to stat each element because 204 * the inode number in the directory is for the entry in the 205 * parent directory, not the inode number of the mounted file. 206 */ 207 save_errno = 0; 208 if (s.st_dev == dev) { 209 for (;;) { 210 if (!(dp = readdir(dir))) 211 goto notfound; 212 if (dp->d_fileno == ino) 213 break; 214 } 215 } else 216 for (;;) { 217 if (!(dp = readdir(dir))) 218 goto notfound; 219 if (ISDOT(dp)) 220 continue; 221 bcopy(dp->d_name, bup, dp->d_namlen + 1); 222 223 /* Save the first error for later. */ 224 if (lstat(up, &s)) { 225 if (!save_errno) 226 save_errno = errno; 227 errno = 0; 228 continue; 229 } 230 if (s.st_dev == dev && s.st_ino == ino) 231 break; 232 } 233 234 /* 235 * Check for length of the current name, preceding slash, 236 * leading slash. 237 */ 238 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 239 size_t len, off; 240 241 if (!ptsize) { 242 errno = ERANGE; 243 goto err; 244 } 245 off = bpt - pt; 246 len = ept - bpt; 247 if ((pt = realloc(pt, ptsize *= 2)) == NULL) 248 goto err; 249 bpt = pt + off; 250 ept = pt + ptsize; 251 bcopy(bpt, ept - len, len); 252 bpt = ept - len; 253 } 254 if (!first) 255 *--bpt = '/'; 256 bpt -= dp->d_namlen; 257 bcopy(dp->d_name, bpt, dp->d_namlen); 258 (void) closedir(dir); 259 dir = NULL; 260 261 /* Truncate any file name. */ 262 *bup = '\0'; 263 } 264 265 notfound: 266 /* 267 * If readdir set errno, use it, not any saved error; otherwise, 268 * didn't find the current directory in its parent directory, set 269 * errno to ENOENT. 270 */ 271 if (!errno) 272 errno = save_errno ? save_errno : ENOENT; 273 /* FALLTHROUGH */ 274 err: 275 save_errno = errno; 276 277 if (ptsize) 278 free(pt); 279 if (dir) 280 (void) closedir(dir); 281 free(up); 282 283 errno = save_errno; 284 return (NULL); 285 } 286