/* * Copyright (c) 1989, 1991, 1993, 1995 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; #endif /* LIBC_SCCS and not lint */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: src/lib/libc/gen/getcwd.c,v 1.25 2003/10/29 10:45:01 tjr Exp $"); #include "namespace.h" #include <sys/param.h> #include <sys/stat.h> #include <dirent.h> #include <errno.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include "un-namespace.h" #define ISDOT(dp) \ (dp->d_name[0] == '.' && (dp->d_name[1] == '\0' || \ (dp->d_name[1] == '.' && dp->d_name[2] == '\0'))) /* * If __getcwd() ever becomes a syscall, we can remove this workaround. * The problem here is that fcntl() assumes a buffer of size MAXPATHLEN, * if size is less than MAXPATHLEN, we need to use a temporary buffer * and see if it fits. We also have to assume that open() or fcntl() * don't fail with errno=ERANGE. */ static inline int __getcwd(char *buf, size_t size) { int fd, err, save; struct stat dot, pt; char *b; if ((fd = open(".", O_RDONLY)) < 0) return -1; if (fstat(fd, &dot) < 0) { save = errno; close(fd); errno = save; return -1; } /* check that the device and inode are non-zero, otherwise punt */ if (dot.st_dev == 0 || dot.st_ino == 0) { close(fd); errno = EINVAL; return -1; } if (size < MAXPATHLEN) { /* the hard case; allocate a buffer of size MAXPATHLEN to use */ b = (char *)alloca(MAXPATHLEN); if (b == NULL) { close(fd); errno = ENOMEM; /* make sure it isn't ERANGE */ return -1; } } else b = buf; err = fcntl(fd, F_GETPATH, b); if (err) { save = errno; close(fd); errno = save; return err; } close(fd); /* * now double-check that the path returned by fcntl() has the same * device and inode number as '.'. */ if (stat(b, &pt) < 0) return -1; /* * Since dot.st_dev and dot.st_ino are non-zero, we don't need to * separately test for pt.st_dev and pt.st_ino being non-zero, because * they have to match */ if (dot.st_dev != pt.st_dev || dot.st_ino != pt.st_ino) { errno = EINVAL; return -1; } /* * For the case where we allocated a buffer, check that it can fit * in the real buffer, and copy it over. */ if (size < MAXPATHLEN) { if (strlen(b) >= size) { errno = ERANGE; return -1; } strcpy(buf, b); } return 0; } __private_extern__ char * __private_getcwd(pt, size, usegetpath) char *pt; size_t size; int usegetpath; { struct dirent *dp; DIR *dir = NULL; dev_t dev; ino_t ino; int first; char *bpt, *bup; struct stat s; dev_t root_dev; ino_t root_ino; size_t ptsize, upsize; int save_errno; char *ept, *eup, *up, c; /* * If no buffer specified by the user, allocate one as necessary. * If a buffer is specified, the size has to be non-zero. The path * is built from the end of the buffer backwards. */ if (pt) { ptsize = 0; if (!size) { errno = EINVAL; return (NULL); } if (size == 1) { errno = ERANGE; return (NULL); } ept = pt + size; } else { if ((pt = malloc(ptsize = MAXPATHLEN)) == NULL) return (NULL); ept = pt + ptsize; } if (usegetpath) { if (__getcwd(pt, ept - pt) == 0) { return (pt); } else if (errno == ERANGE) /* failed because buffer too small */ return NULL; } bpt = ept - 1; *bpt = '\0'; /* * Allocate bytes MAXPATHLEN) for the string of "../"'s. * Should always be enough (it's 340 levels). If it's not, allocate * as necessary. Special case the first stat, it's ".", not "..". */ if ((up = malloc(upsize = MAXPATHLEN)) == NULL) goto err; eup = up + MAXPATHLEN; bup = up; up[0] = '.'; up[1] = '\0'; /* Save root values, so know when to stop. */ if (stat("/", &s)) goto err; root_dev = s.st_dev; root_ino = s.st_ino; errno = 0; /* XXX readdir has no error return. */ for (first = 1;; first = 0) { /* Stat the current level. */ if (lstat(up, &s)) goto err; /* Save current node values. */ ino = s.st_ino; dev = s.st_dev; /* Check for reaching root. */ if (root_dev == dev && root_ino == ino) { *--bpt = '/'; /* * It's unclear that it's a requirement to copy the * path to the beginning of the buffer, but it's always * been that way and stuff would probably break. */ bcopy(bpt, pt, ept - bpt); free(up); return (pt); } /* * Build pointer to the parent directory, allocating memory * as necessary. Max length is 3 for "../", the largest * possible component name, plus a trailing NUL. */ if (bup + 3 + MAXNAMLEN + 1 >= eup) { if ((up = reallocf(up, upsize *= 2)) == NULL) goto err; bup = up; eup = up + upsize; } *bup++ = '.'; *bup++ = '.'; *bup = '\0'; /* Open and stat parent directory. */ if (!(dir = opendir(up)) || _fstat(dirfd(dir), &s)) goto err; /* Add trailing slash for next directory. */ *bup++ = '/'; *bup = '\0'; /* * If it's a mount point, have to stat each element because * the inode number in the directory is for the entry in the * parent directory, not the inode number of the mounted file. */ save_errno = 0; if (s.st_dev == dev) { for (;;) { if (!(dp = readdir(dir))) goto notfound; if (dp->d_fileno == ino) break; } } else for (;;) { if (!(dp = readdir(dir))) goto notfound; if (ISDOT(dp)) continue; bcopy(dp->d_name, bup, dp->d_namlen + 1); /* Save the first error for later. */ if (lstat(up, &s)) { if (!save_errno) save_errno = errno; errno = 0; continue; } if (s.st_dev == dev && s.st_ino == ino) break; } /* * Check for length of the current name, preceding slash, * leading slash. */ if (bpt - pt < dp->d_namlen + (first ? 1 : 2)) { size_t len, off; if (!ptsize) { errno = ERANGE; goto err; } off = bpt - pt; len = ept - bpt; if ((pt = reallocf(pt, ptsize *= 2)) == NULL) goto err; bpt = pt + off; ept = pt + ptsize; bcopy(bpt, ept - len, len); bpt = ept - len; } if (!first) *--bpt = '/'; bpt -= dp->d_namlen; bcopy(dp->d_name, bpt, dp->d_namlen); (void) closedir(dir); dir = NULL; /* Truncate any file name. */ *bup = '\0'; } notfound: /* * If readdir set errno, use it, not any saved error; otherwise, * didn't find the current directory in its parent directory, set * errno to ENOENT. */ if (!errno) errno = save_errno ? save_errno : ENOENT; /* FALLTHROUGH */ err: save_errno = errno; if (ptsize) free(pt); if (dir) (void) closedir(dir); free(up); errno = save_errno; return (NULL); } char * getcwd(pt, size) char *pt; size_t size; { return __private_getcwd(pt, size, 1); }