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 * $FreeBSD: src/lib/libc/gen/getcwd.c,v 1.18 1999/09/28 13:24:13 marcel Exp $ 34 * $DragonFly: src/lib/libc/gen/getcwd.c,v 1.2 2003/06/17 04:26:42 dillon Exp $ 35 * 36 * @(#)getcwd.c 8.5 (Berkeley) 2/7/95 37 */ 38 39 #include <sys/param.h> 40 #include <sys/stat.h> 41 42 #include <dirent.h> 43 #include <errno.h> 44 #include <fcntl.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <unistd.h> 49 #include <signal.h> 50 51 #define ISDOT(dp) \ 52 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 53 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 54 55 static int have__getcwd = 1; /* 0 = no, 1 = perhaps, 2 = yes */ 56 57 char * 58 getcwd(pt, size) 59 char *pt; 60 size_t size; 61 { 62 register struct dirent *dp; 63 register DIR *dir = NULL; 64 register dev_t dev; 65 register ino_t ino; 66 register int first; 67 register char *bpt, *bup; 68 struct stat s; 69 dev_t root_dev; 70 ino_t root_ino; 71 size_t ptsize, upsize; 72 int save_errno; 73 char *ept, *eup, *up, c; 74 75 /* 76 * If no buffer specified by the user, allocate one as necessary. 77 * If a buffer is specified, the size has to be non-zero. The path 78 * is built from the end of the buffer backwards. 79 */ 80 if (pt) { 81 ptsize = 0; 82 if (!size) { 83 errno = EINVAL; 84 return (NULL); 85 } 86 if (size == 1) { 87 errno = ERANGE; 88 return (NULL); 89 } 90 ept = pt + size; 91 } else { 92 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 93 return (NULL); 94 ept = pt + ptsize; 95 } 96 #if defined(__NETBSD_SYSCALLS) 97 have__getcwd = 0; 98 #else 99 if (have__getcwd) { 100 struct sigaction sa, osa; 101 int sigsys_installed = 0; 102 int ret; 103 104 if (have__getcwd == 1) { /* unsure? */ 105 sigemptyset(&sa.sa_mask); 106 sa.sa_flags = 0; 107 sa.sa_handler = SIG_IGN; 108 if (sigaction(SIGSYS, &sa, &osa) >= 0) 109 sigsys_installed = 1; 110 } 111 ret = __getcwd(pt, ept - pt); 112 if (sigsys_installed == 1) { 113 int oerrno = errno; 114 sigaction(SIGSYS, &osa, NULL); 115 errno = oerrno; 116 } 117 /* XXX a bogus syscall seems to return EINVAL(!) */ 118 if (ret < 0 && (errno == ENOSYS || errno == EINVAL)) 119 have__getcwd = 0; 120 else if (have__getcwd == 1) 121 have__getcwd = 2; /* yep, remember we have it */ 122 if (ret == 0) { 123 if (*pt != '/') { 124 bpt = pt; 125 ept = pt + strlen(pt) - 1; 126 while (bpt < ept) { 127 c = *bpt; 128 *bpt++ = *ept; 129 *ept-- = c; 130 } 131 } 132 return (pt); 133 } 134 } 135 #endif 136 bpt = ept - 1; 137 *bpt = '\0'; 138 139 /* 140 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 141 * Should always be enough (it's 340 levels). If it's not, allocate 142 * as necessary. Special case the first stat, it's ".", not "..". 143 */ 144 if ((up = malloc(upsize = 1024 - 4)) == NULL) 145 goto err; 146 eup = up + MAXPATHLEN; 147 bup = up; 148 up[0] = '.'; 149 up[1] = '\0'; 150 151 /* Save root values, so know when to stop. */ 152 if (stat("/", &s)) 153 goto err; 154 root_dev = s.st_dev; 155 root_ino = s.st_ino; 156 157 errno = 0; /* XXX readdir has no error return. */ 158 159 for (first = 1;; first = 0) { 160 /* Stat the current level. */ 161 if (lstat(up, &s)) 162 goto err; 163 164 /* Save current node values. */ 165 ino = s.st_ino; 166 dev = s.st_dev; 167 168 /* Check for reaching root. */ 169 if (root_dev == dev && root_ino == ino) { 170 *--bpt = '/'; 171 /* 172 * It's unclear that it's a requirement to copy the 173 * path to the beginning of the buffer, but it's always 174 * been that way and stuff would probably break. 175 */ 176 bcopy(bpt, pt, ept - bpt); 177 free(up); 178 return (pt); 179 } 180 181 /* 182 * Build pointer to the parent directory, allocating memory 183 * as necessary. Max length is 3 for "../", the largest 184 * possible component name, plus a trailing NULL. 185 */ 186 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 187 if ((up = reallocf(up, upsize *= 2)) == NULL) 188 goto err; 189 bup = up; 190 eup = up + upsize; 191 } 192 *bup++ = '.'; 193 *bup++ = '.'; 194 *bup = '\0'; 195 196 /* Open and stat parent directory. */ 197 if (!(dir = opendir(up)) || fstat(dirfd(dir), &s)) 198 goto err; 199 200 /* Add trailing slash for next directory. */ 201 *bup++ = '/'; 202 *bup = '\0'; 203 204 /* 205 * If it's a mount point, have to stat each element because 206 * the inode number in the directory is for the entry in the 207 * parent directory, not the inode number of the mounted file. 208 */ 209 save_errno = 0; 210 if (s.st_dev == dev) { 211 for (;;) { 212 if (!(dp = readdir(dir))) 213 goto notfound; 214 if (dp->d_fileno == ino) 215 break; 216 } 217 } else 218 for (;;) { 219 if (!(dp = readdir(dir))) 220 goto notfound; 221 if (ISDOT(dp)) 222 continue; 223 bcopy(dp->d_name, bup, dp->d_namlen + 1); 224 225 /* Save the first error for later. */ 226 if (lstat(up, &s)) { 227 if (!save_errno) 228 save_errno = errno; 229 errno = 0; 230 continue; 231 } 232 if (s.st_dev == dev && s.st_ino == ino) 233 break; 234 } 235 236 /* 237 * Check for length of the current name, preceding slash, 238 * leading slash. 239 */ 240 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 241 size_t len, off; 242 243 if (!ptsize) { 244 errno = ERANGE; 245 goto err; 246 } 247 off = bpt - pt; 248 len = ept - bpt; 249 if ((pt = realloc(pt, ptsize *= 2)) == NULL) 250 goto err; 251 bpt = pt + off; 252 ept = pt + ptsize; 253 bcopy(bpt, ept - len, len); 254 bpt = ept - len; 255 } 256 if (!first) 257 *--bpt = '/'; 258 bpt -= dp->d_namlen; 259 bcopy(dp->d_name, bpt, dp->d_namlen); 260 (void) closedir(dir); 261 dir = NULL; 262 263 /* Truncate any file name. */ 264 *bup = '\0'; 265 } 266 267 notfound: 268 /* 269 * If readdir set errno, use it, not any saved error; otherwise, 270 * didn't find the current directory in its parent directory, set 271 * errno to ENOENT. 272 */ 273 if (!errno) 274 errno = save_errno ? save_errno : ENOENT; 275 /* FALLTHROUGH */ 276 err: 277 save_errno = errno; 278 279 if (ptsize) 280 free(pt); 281 if (dir) 282 (void) closedir(dir); 283 free(up); 284 285 errno = save_errno; 286 return (NULL); 287 } 288