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 1.4 2005/01/31 22:29:15 dillon Exp $ 35 * 36 * @(#)getcwd.c 8.5 (Berkeley) 2/7/95 37 */ 38 39 #include "namespace.h" 40 #include <sys/param.h> 41 #include <sys/stat.h> 42 43 #include <dirent.h> 44 #include <errno.h> 45 #include <fcntl.h> 46 #include <signal.h> 47 #include <stdio.h> 48 #include <stdlib.h> 49 #include <string.h> 50 #include <unistd.h> 51 #include "un-namespace.h" 52 53 #define ISDOT(dp) \ 54 (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ 55 (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) 56 57 static int have__getcwd = 1; /* 0 = no, 1 = perhaps, 2 = yes */ 58 59 char * 60 getcwd(pt, size) 61 char *pt; 62 size_t size; 63 { 64 struct dirent *dp; 65 DIR *dir = NULL; 66 dev_t dev; 67 ino_t ino; 68 int first; 69 char *bpt, *bup; 70 struct stat s; 71 dev_t root_dev; 72 ino_t root_ino; 73 size_t ptsize, upsize; 74 int save_errno; 75 char *ept, *eup, *up, c; 76 77 /* 78 * If no buffer specified by the user, allocate one as necessary. 79 * If a buffer is specified, the size has to be non-zero. The path 80 * is built from the end of the buffer backwards. 81 */ 82 if (pt) { 83 ptsize = 0; 84 if (!size) { 85 errno = EINVAL; 86 return (NULL); 87 } 88 if (size == 1) { 89 errno = ERANGE; 90 return (NULL); 91 } 92 ept = pt + size; 93 } else { 94 if ((pt = malloc(ptsize = 1024 - 4)) == NULL) 95 return (NULL); 96 ept = pt + ptsize; 97 } 98 #if defined(__NETBSD_SYSCALLS) 99 have__getcwd = 0; 100 #else 101 if (have__getcwd) { 102 struct sigaction sa, osa; 103 int sigsys_installed = 0; 104 int ret; 105 106 if (have__getcwd == 1) { /* unsure? */ 107 sigemptyset(&sa.sa_mask); 108 sa.sa_flags = 0; 109 sa.sa_handler = SIG_IGN; 110 if (sigaction(SIGSYS, &sa, &osa) >= 0) 111 sigsys_installed = 1; 112 } 113 ret = __getcwd(pt, ept - pt); 114 if (sigsys_installed == 1) { 115 int oerrno = errno; 116 sigaction(SIGSYS, &osa, NULL); 117 errno = oerrno; 118 } 119 /* XXX a bogus syscall seems to return EINVAL(!) */ 120 if (ret < 0 && (errno == ENOSYS || errno == EINVAL)) 121 have__getcwd = 0; 122 else if (have__getcwd == 1) 123 have__getcwd = 2; /* yep, remember we have it */ 124 if (ret == 0) { 125 if (*pt != '/') { 126 bpt = pt; 127 ept = pt + strlen(pt) - 1; 128 while (bpt < ept) { 129 c = *bpt; 130 *bpt++ = *ept; 131 *ept-- = c; 132 } 133 } 134 return (pt); 135 } 136 } 137 #endif 138 bpt = ept - 1; 139 *bpt = '\0'; 140 141 /* 142 * Allocate bytes (1024 - malloc space) for the string of "../"'s. 143 * Should always be enough (it's 340 levels). If it's not, allocate 144 * as necessary. Special case the first stat, it's ".", not "..". 145 */ 146 if ((up = malloc(upsize = 1024 - 4)) == NULL) 147 goto err; 148 eup = up + MAXPATHLEN; 149 bup = up; 150 up[0] = '.'; 151 up[1] = '\0'; 152 153 /* Save root values, so know when to stop. */ 154 if (stat("/", &s)) 155 goto err; 156 root_dev = s.st_dev; 157 root_ino = s.st_ino; 158 159 errno = 0; /* XXX readdir has no error return. */ 160 161 for (first = 1;; first = 0) { 162 /* Stat the current level. */ 163 if (lstat(up, &s)) 164 goto err; 165 166 /* Save current node values. */ 167 ino = s.st_ino; 168 dev = s.st_dev; 169 170 /* Check for reaching root. */ 171 if (root_dev == dev && root_ino == ino) { 172 *--bpt = '/'; 173 /* 174 * It's unclear that it's a requirement to copy the 175 * path to the beginning of the buffer, but it's always 176 * been that way and stuff would probably break. 177 */ 178 bcopy(bpt, pt, ept - bpt); 179 free(up); 180 return (pt); 181 } 182 183 /* 184 * Build pointer to the parent directory, allocating memory 185 * as necessary. Max length is 3 for "../", the largest 186 * possible component name, plus a trailing NULL. 187 */ 188 if (bup + 3 + MAXNAMLEN + 1 >= eup) { 189 if ((up = reallocf(up, upsize *= 2)) == NULL) 190 goto err; 191 bup = up; 192 eup = up + upsize; 193 } 194 *bup++ = '.'; 195 *bup++ = '.'; 196 *bup = '\0'; 197 198 /* Open and stat parent directory. */ 199 if (!(dir = opendir(up)) || _fstat(dirfd(dir), &s)) 200 goto err; 201 202 /* Add trailing slash for next directory. */ 203 *bup++ = '/'; 204 *bup = '\0'; 205 206 /* 207 * If it's a mount point, have to stat each element because 208 * the inode number in the directory is for the entry in the 209 * parent directory, not the inode number of the mounted file. 210 */ 211 save_errno = 0; 212 if (s.st_dev == dev) { 213 for (;;) { 214 if (!(dp = readdir(dir))) 215 goto notfound; 216 if (dp->d_fileno == ino) 217 break; 218 } 219 } else 220 for (;;) { 221 if (!(dp = readdir(dir))) 222 goto notfound; 223 if (ISDOT(dp)) 224 continue; 225 bcopy(dp->d_name, bup, dp->d_namlen + 1); 226 227 /* Save the first error for later. */ 228 if (lstat(up, &s)) { 229 if (!save_errno) 230 save_errno = errno; 231 errno = 0; 232 continue; 233 } 234 if (s.st_dev == dev && s.st_ino == ino) 235 break; 236 } 237 238 /* 239 * Check for length of the current name, preceding slash, 240 * leading slash. 241 */ 242 if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { 243 size_t len, off; 244 245 if (!ptsize) { 246 errno = ERANGE; 247 goto err; 248 } 249 off = bpt - pt; 250 len = ept - bpt; 251 if ((pt = realloc(pt, ptsize *= 2)) == NULL) 252 goto err; 253 bpt = pt + off; 254 ept = pt + ptsize; 255 bcopy(bpt, ept - len, len); 256 bpt = ept - len; 257 } 258 if (!first) 259 *--bpt = '/'; 260 bpt -= dp->d_namlen; 261 bcopy(dp->d_name, bpt, dp->d_namlen); 262 (void) closedir(dir); 263 dir = NULL; 264 265 /* Truncate any file name. */ 266 *bup = '\0'; 267 } 268 269 notfound: 270 /* 271 * If readdir set errno, use it, not any saved error; otherwise, 272 * didn't find the current directory in its parent directory, set 273 * errno to ENOENT. 274 */ 275 if (!errno) 276 errno = save_errno ? save_errno : ENOENT; 277 /* FALLTHROUGH */ 278 err: 279 save_errno = errno; 280 281 if (ptsize) 282 free(pt); 283 if (dir) 284 (void) closedir(dir); 285 free(up); 286 287 errno = save_errno; 288 return (NULL); 289 } 290