GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libc/stdlib/realpath.c Lines: 0 91 0.0 %
Date: 2017-11-07 Branches: 0 63 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: realpath.c,v 1.21 2016/08/28 04:08:59 guenther Exp $ */
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/*
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 * Copyright (c) 2003 Constantin S. Svintsoff <kostik@iclub.nsu.ru>
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. The names of the authors may not be used to endorse or promote
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 *    products derived from this software without specific prior written
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 *    permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <limits.h>
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/* A slightly modified copy of this file exists in libexec/ld.so */
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/*
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 * char *realpath(const char *path, char resolved[PATH_MAX]);
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 *
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 * Find the real name of path, by removing all ".", ".." and symlink
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 * components.  Returns (resolved) on success, or (NULL) on failure,
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 * in which case the path which caused trouble is left in (resolved).
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 */
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char *
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realpath(const char *path, char *resolved)
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{
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	char *p, *q, *s;
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	size_t left_len, resolved_len;
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	unsigned symlinks;
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	int serrno, slen, mem_allocated;
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	char left[PATH_MAX], next_token[PATH_MAX], symlink[PATH_MAX];
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	if (path[0] == '\0') {
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		errno = ENOENT;
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		return (NULL);
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	}
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	serrno = errno;
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	if (resolved == NULL) {
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		resolved = malloc(PATH_MAX);
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		if (resolved == NULL)
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			return (NULL);
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		mem_allocated = 1;
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	} else
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		mem_allocated = 0;
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	symlinks = 0;
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	if (path[0] == '/') {
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		resolved[0] = '/';
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		resolved[1] = '\0';
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		if (path[1] == '\0')
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			return (resolved);
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		resolved_len = 1;
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		left_len = strlcpy(left, path + 1, sizeof(left));
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	} else {
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		if (getcwd(resolved, PATH_MAX) == NULL) {
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			if (mem_allocated)
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				free(resolved);
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			else
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				strlcpy(resolved, ".", PATH_MAX);
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			return (NULL);
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		}
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		resolved_len = strlen(resolved);
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		left_len = strlcpy(left, path, sizeof(left));
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	}
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	if (left_len >= sizeof(left) || resolved_len >= PATH_MAX) {
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		errno = ENAMETOOLONG;
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		goto err;
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	}
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	/*
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	 * Iterate over path components in `left'.
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	 */
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	while (left_len != 0) {
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		/*
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		 * Extract the next path component and adjust `left'
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		 * and its length.
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		 */
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		p = strchr(left, '/');
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		s = p ? p : left + left_len;
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		if (s - left >= sizeof(next_token)) {
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			errno = ENAMETOOLONG;
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			goto err;
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		}
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		memcpy(next_token, left, s - left);
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		next_token[s - left] = '\0';
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		left_len -= s - left;
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		if (p != NULL)
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			memmove(left, s + 1, left_len + 1);
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		if (resolved[resolved_len - 1] != '/') {
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			if (resolved_len + 1 >= PATH_MAX) {
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				errno = ENAMETOOLONG;
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				goto err;
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			}
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			resolved[resolved_len++] = '/';
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			resolved[resolved_len] = '\0';
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		}
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		if (next_token[0] == '\0')
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			continue;
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		else if (strcmp(next_token, ".") == 0)
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			continue;
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		else if (strcmp(next_token, "..") == 0) {
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			/*
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			 * Strip the last path component except when we have
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			 * single "/"
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			 */
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			if (resolved_len > 1) {
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				resolved[resolved_len - 1] = '\0';
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				q = strrchr(resolved, '/') + 1;
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				*q = '\0';
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				resolved_len = q - resolved;
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			}
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			continue;
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		}
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		/*
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		 * Append the next path component and lstat() it. If
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		 * lstat() fails we still can return successfully if
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		 * there are no more path components left.
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		 */
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		resolved_len = strlcat(resolved, next_token, PATH_MAX);
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		if (resolved_len >= PATH_MAX) {
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			errno = ENAMETOOLONG;
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			goto err;
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		}
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		slen = readlink(resolved, symlink, sizeof(symlink) - 1);
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		if (slen < 0) {
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			switch (errno) {
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			case EINVAL:
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				/* not a symlink, continue to next component */
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				continue;
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			case ENOENT:
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				if (p == NULL) {
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					errno = serrno;
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					return (resolved);
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				}
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				/* FALLTHROUGH */
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			default:
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				goto err;
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			}
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		} else {
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			if (symlinks++ > SYMLOOP_MAX) {
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				errno = ELOOP;
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				goto err;
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			}
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			symlink[slen] = '\0';
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			if (symlink[0] == '/') {
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				resolved[1] = 0;
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				resolved_len = 1;
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			} else if (resolved_len > 1) {
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				/* Strip the last path component. */
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				resolved[resolved_len - 1] = '\0';
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				q = strrchr(resolved, '/') + 1;
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				*q = '\0';
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				resolved_len = q - resolved;
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			}
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			/*
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			 * If there are any path components left, then
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			 * append them to symlink. The result is placed
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			 * in `left'.
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			 */
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			if (p != NULL) {
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				if (symlink[slen - 1] != '/') {
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					if (slen + 1 >= sizeof(symlink)) {
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						errno = ENAMETOOLONG;
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						goto err;
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					}
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					symlink[slen] = '/';
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					symlink[slen + 1] = 0;
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				}
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				left_len = strlcat(symlink, left, sizeof(symlink));
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				if (left_len >= sizeof(symlink)) {
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					errno = ENAMETOOLONG;
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					goto err;
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				}
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			}
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			left_len = strlcpy(left, symlink, sizeof(left));
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		}
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	}
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	/*
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	 * Remove trailing slash except when the resolved pathname
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	 * is a single "/".
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	 */
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	if (resolved_len > 1 && resolved[resolved_len - 1] == '/')
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		resolved[resolved_len - 1] = '\0';
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	return (resolved);
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err:
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	if (mem_allocated)
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		free(resolved);
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	return (NULL);
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}