/* $NetBSD: getcwd.c,v 1.53 2012/06/21 23:29:23 enami Exp $ */ /* * Copyright (c) 1989, 1991, 1993, 1995 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry. * * 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. 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. */ #include <sys/cdefs.h> #if defined(LIBC_SCCS) && !defined(lint) #if 0 static char sccsid[] = "@(#)getcwd.c 8.5 (Berkeley) 2/7/95"; #else __RCSID("$NetBSD: getcwd.c,v 1.53 2012/06/21 23:29:23 enami Exp $"); #endif #endif /* LIBC_SCCS and not lint */ #include "namespace.h" #include <sys/param.h> #include <sys/stat.h> #include <assert.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <ssp/ssp.h> #include "extern.h" #ifdef __weak_alias __weak_alias(getcwd,_getcwd) __weak_alias(_sys_getcwd,_getcwd) __weak_alias(realpath,_realpath) #endif /* * char *realpath(const char *path, char *resolved); * * Find the real name of path, by removing all ".", ".." and symlink * components. Returns (resolved) on success, or (NULL) on failure, * in which case the path which caused trouble is left in (resolved). */ char * realpath(const char * __restrict path, char * __restrict resolved) { struct stat sb; int idx = 0, nlnk = 0; const char *q; char *p, wbuf[2][MAXPATHLEN], *fres; size_t len; ssize_t n; /* POSIX sez we must test for this */ if (path == NULL) { errno = EINVAL; return NULL; } if (resolved == NULL) { fres = resolved = malloc(MAXPATHLEN); if (resolved == NULL) return NULL; } else fres = NULL; /* * Build real path one by one with paying an attention to ., * .. and symbolic link. */ /* * `p' is where we'll put a new component with prepending * a delimiter. */ p = resolved; if (*path == '\0') { *p = '\0'; errno = ENOENT; goto out; } /* If relative path, start from current working directory. */ if (*path != '/') { /* check for resolved pointer to appease coverity */ if (resolved && getcwd(resolved, MAXPATHLEN) == NULL) { p[0] = '.'; p[1] = '\0'; goto out; } len = strlen(resolved); if (len > 1) p += len; } loop: /* Skip any slash. */ while (*path == '/') path++; if (*path == '\0') { if (p == resolved) *p++ = '/'; *p = '\0'; return resolved; } /* Find the end of this component. */ q = path; do q++; while (*q != '/' && *q != '\0'); /* Test . or .. */ if (path[0] == '.') { if (q - path == 1) { path = q; goto loop; } if (path[1] == '.' && q - path == 2) { /* Trim the last component. */ if (p != resolved) while (*--p != '/') continue; path = q; goto loop; } } /* Append this component. */ if (p - resolved + 1 + q - path + 1 > MAXPATHLEN) { errno = ENAMETOOLONG; if (p == resolved) *p++ = '/'; *p = '\0'; goto out; } p[0] = '/'; memcpy(&p[1], path, /* LINTED We know q > path. */ q - path); p[1 + q - path] = '\0'; /* * If this component is a symlink, toss it and prepend link * target to unresolved path. */ if (lstat(resolved, &sb) == -1) goto out; if (S_ISLNK(sb.st_mode)) { if (nlnk++ >= MAXSYMLINKS) { errno = ELOOP; goto out; } n = readlink(resolved, wbuf[idx], sizeof(wbuf[0]) - 1); if (n < 0) goto out; if (n == 0) { errno = ENOENT; goto out; } /* Append unresolved path to link target and switch to it. */ if (n + (len = strlen(q)) + 1 > sizeof(wbuf[0])) { errno = ENAMETOOLONG; goto out; } memcpy(&wbuf[idx][n], q, len + 1); path = wbuf[idx]; idx ^= 1; /* If absolute symlink, start from root. */ if (*path == '/') p = resolved; goto loop; } if (*q == '/' && !S_ISDIR(sb.st_mode)) { errno = ENOTDIR; goto out; } /* Advance both resolved and unresolved path. */ p += 1 + q - path; path = q; goto loop; out: free(fres); return NULL; } char * __ssp_real(getcwd)(char *pt, size_t size) { char *npt; /* * If a buffer is specified, the size has to be non-zero. */ if (pt != NULL) { if (size == 0) { /* __getcwd(pt, 0) results ERANGE. */ errno = EINVAL; return (NULL); } if (__getcwd(pt, size) >= 0) return (pt); return (NULL); } /* * If no buffer specified by the user, allocate one as necessary. */ size = 1024 >> 1; do { if ((npt = realloc(pt, size <<= 1)) == NULL) break; pt = npt; if (__getcwd(pt, size) >= 0) return (pt); } while (size <= MAXPATHLEN * 4 && errno == ERANGE); free(pt); return (NULL); }
