ojluni/src/main/native/canonicalize_md.c - platform/libcore - Git at Google

 /*
  * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.  Oracle designates this
  * particular file as subject to the "Classpath" exception as provided
  * by Oracle in the LICENSE file that accompanied this code.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  */

 /*
  * Pathname canonicalization for Unix file systems
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <errno.h>
 #include <limits.h>
 #if !defined(_ALLBSD_SOURCE)
 #include <alloca.h>
 #endif


 /* Note: The comments in this file use the terminology
          defined in the java.io.File class */


 /* Check the given name sequence to see if it can be further collapsed.
    Return zero if not, otherwise return the number of names in the sequence. */

 static int
 collapsible(char *names)
 {
     char *p = names;
     int dots = 0, n = 0;

     while (*p) {
         if ((p[0] == '.') && ((p[1] == '\0')
                               || (p[1] == '/')
                               || ((p[1] == '.') && ((p[2] == '\0')
                                                     || (p[2] == '/'))))) {
             dots = 1;
         }
         n++;
         while (*p) {
             if (*p == '/') {
                 p++;
                 break;
             }
             p++;
         }
     }
     return (dots ? n : 0);
 }


 /* Split the names in the given name sequence,
    replacing slashes with nulls and filling in the given index array */

 static void
 splitNames(char *names, char **ix)
 {
     char *p = names;
     int i = 0;

     while (*p) {
         ix[i++] = p++;
         while (*p) {
             if (*p == '/') {
                 *p++ = '\0';
                 break;
             }
             p++;
         }
     }
 }


 /* Join the names in the given name sequence, ignoring names whose index
    entries have been cleared and replacing nulls with slashes as needed */

 static void
 joinNames(char *names, int nc, char **ix)
 {
     int i;
     char *p;

     for (i = 0, p = names; i < nc; i++) {
         if (!ix[i]) continue;
         if (i > 0) {
             p[-1] = '/';
         }
         if (p == ix[i]) {
             p += strlen(p) + 1;
         } else {
             char *q = ix[i];
             while ((*p++ = *q++));
         }
     }
     *p = '\0';
 }


 /* Collapse "." and ".." names in the given path wherever possible.
    A "." name may always be eliminated; a ".." name may be eliminated if it
    follows a name that is neither "." nor "..".  This is a syntactic operation
    that performs no filesystem queries, so it should only be used to cleanup
    after invoking the realpath() procedure. */

 static void
 collapse(char *path)
 {
     char *names = (path[0] == '/') ? path + 1 : path; /* Preserve first '/' */
     int nc;
     char **ix;
     int i, j;
     char *p, *q;

     nc = collapsible(names);
     if (nc < 2) return;         /* Nothing to do */
     ix = (char **)alloca(nc * sizeof(char *));
     splitNames(names, ix);

     for (i = 0; i < nc; i++) {
         int dots = 0;

         /* Find next occurrence of "." or ".." */
         do {
             char *p = ix[i];
             if (p[0] == '.') {
                 if (p[1] == '\0') {
                     dots = 1;
                     break;
                 }
                 if ((p[1] == '.') && (p[2] == '\0')) {
                     dots = 2;
                     break;
                 }
             }
             i++;
         } while (i < nc);
         if (i >= nc) break;

         /* At this point i is the index of either a "." or a "..", so take the
            appropriate action and then continue the outer loop */
         if (dots == 1) {
             /* Remove this instance of "." */
             ix[i] = 0;
         }
         else {
             /* If there is a preceding name, remove both that name and this
                instance of ".."; otherwise, leave the ".." as is */
             for (j = i - 1; j >= 0; j--) {
                 if (ix[j]) break;
             }
             if (j < 0) continue;
             ix[j] = 0;
             ix[i] = 0;
         }
         /* i will be incremented at the top of the loop */
     }

     joinNames(names, nc, ix);
 }


 /* Convert a pathname to canonical form.  The input path is assumed to contain
    no duplicate slashes.  On Solaris we can use realpath() to do most of the
    work, though once that's done we still must collapse any remaining "." and
    ".." names by hand. */

 int
 canonicalize(char *original, char *resolved, int len)
 {
     if (len < PATH_MAX) {
         errno = EINVAL;
         return -1;
     }

     if (strlen(original) > PATH_MAX) {
         errno = ENAMETOOLONG;
         return -1;
     }

     /* First try realpath() on the entire path */
     if (realpath(original, resolved)) {
         /* That worked, so return it */
         collapse(resolved);
         return 0;
     }
     else {
         /* Something's bogus in the original path, so remove names from the end
            until either some subpath works or we run out of names */
         char *p, *end, *r = NULL;
         char path[PATH_MAX + 1];

         strncpy(path, original, sizeof(path));
         if (path[PATH_MAX] != '\0') {
             errno = ENAMETOOLONG;
             return -1;
         }
         end = path + strlen(path);

         for (p = end; p > path;) {

             /* Skip last element */
             while ((--p > path) && (*p != '/'));
             if (p == path) break;

             /* Try realpath() on this subpath */
             *p = '\0';
             r = realpath(path, resolved);
             *p = (p == end) ? '\0' : '/';

             if (r != NULL) {
                 /* The subpath has a canonical path */
                 break;
             }
             else if (errno == ENOENT || errno == ENOTDIR || errno == EACCES) {
                 /* If the lookup of a particular subpath fails because the file
                    does not exist, because it is of the wrong type, or because
                    access is denied, then remove its last name and try again.
                    Other I/O problems cause an error return. */
                 continue;
             }
             else {
                 return -1;
             }
         }

         if (r != NULL) {
             /* Append unresolved subpath to resolved subpath */
             int rn = strlen(r);
             if (rn + (int)strlen(p) >= len) {
                 /* Buffer overflow */
                 errno = ENAMETOOLONG;
                 return -1;
             }
             if ((rn > 0) && (r[rn - 1] == '/') && (*p == '/')) {
                 /* Avoid duplicate slashes */
                 p++;
             }
             strcpy(r + rn, p);
             collapse(r);
             return 0;
         }
         else {
             /* Nothing resolved, so just return the original path */
             strcpy(resolved, path);
             collapse(resolved);
             return 0;
         }
     }

 }
	/*
	* Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	* Pathname canonicalization for Unix file systems
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/stat.h>
	#include <errno.h>
	#include <limits.h>
	#if !defined(_ALLBSD_SOURCE)
	#include <alloca.h>
	#endif


	/* Note: The comments in this file use the terminology
	defined in the java.io.File class */


	/* Check the given name sequence to see if it can be further collapsed.
	Return zero if not, otherwise return the number of names in the sequence. */

	static int
	collapsible(char *names)
	{
	char *p = names;
	int dots = 0, n = 0;

	while (*p) {
	if ((p[0] == '.') && ((p[1] == '\0')
	\|\| (p[1] == '/')
	\|\| ((p[1] == '.') && ((p[2] == '\0')
	\|\| (p[2] == '/'))))) {
	dots = 1;
	}
	n++;
	while (*p) {
	if (*p == '/') {
	p++;
	break;
	}
	p++;
	}
	}
	return (dots ? n : 0);
	}


	/* Split the names in the given name sequence,
	replacing slashes with nulls and filling in the given index array */

	static void
	splitNames(char names, char *ix)
	{
	char *p = names;
	int i = 0;

	while (*p) {
	ix[i++] = p++;
	while (*p) {
	if (*p == '/') {
	*p++ = '\0';
	break;
	}
	p++;
	}
	}
	}


	/* Join the names in the given name sequence, ignoring names whose index
	entries have been cleared and replacing nulls with slashes as needed */

	static void
	joinNames(char names, int nc, char *ix)
	{
	int i;
	char *p;

	for (i = 0, p = names; i < nc; i++) {
	if (!ix[i]) continue;
	if (i > 0) {
	p[-1] = '/';
	}
	if (p == ix[i]) {
	p += strlen(p) + 1;
	} else {
	char *q = ix[i];
	while ((p++ = q++));
	}
	}
	*p = '\0';
	}


	/* Collapse "." and ".." names in the given path wherever possible.
	A "." name may always be eliminated; a ".." name may be eliminated if it
	follows a name that is neither "." nor "..". This is a syntactic operation
	that performs no filesystem queries, so it should only be used to cleanup
	after invoking the realpath() procedure. */

	static void
	collapse(char *path)
	{
	char names = (path[0] == '/') ? path + 1 : path; / Preserve first '/' */
	int nc;
	char **ix;
	int i, j;
	char p, q;

	nc = collapsible(names);
	if (nc < 2) return; /* Nothing to do */
	ix = (char *)alloca(nc sizeof(char *));
	splitNames(names, ix);

	for (i = 0; i < nc; i++) {
	int dots = 0;

	/* Find next occurrence of "." or ".." */
	do {
	char *p = ix[i];
	if (p[0] == '.') {
	if (p[1] == '\0') {
	dots = 1;
	break;
	}
	if ((p[1] == '.') && (p[2] == '\0')) {
	dots = 2;
	break;
	}
	}
	i++;
	} while (i < nc);
	if (i >= nc) break;

	/* At this point i is the index of either a "." or a "..", so take the
	appropriate action and then continue the outer loop */
	if (dots == 1) {
	/* Remove this instance of "." */
	ix[i] = 0;
	}
	else {
	/* If there is a preceding name, remove both that name and this
	instance of ".."; otherwise, leave the ".." as is */
	for (j = i - 1; j >= 0; j--) {
	if (ix[j]) break;
	}
	if (j < 0) continue;
	ix[j] = 0;
	ix[i] = 0;
	}
	/* i will be incremented at the top of the loop */
	}

	joinNames(names, nc, ix);
	}


	/* Convert a pathname to canonical form. The input path is assumed to contain
	no duplicate slashes. On Solaris we can use realpath() to do most of the
	work, though once that's done we still must collapse any remaining "." and
	".." names by hand. */

	int
	canonicalize(char original, char resolved, int len)
	{
	if (len < PATH_MAX) {
	errno = EINVAL;
	return -1;
	}

	if (strlen(original) > PATH_MAX) {
	errno = ENAMETOOLONG;
	return -1;
	}

	/* First try realpath() on the entire path */
	if (realpath(original, resolved)) {
	/* That worked, so return it */
	collapse(resolved);
	return 0;
	}
	else {
	/* Something's bogus in the original path, so remove names from the end
	until either some subpath works or we run out of names */
	char p, end, *r = NULL;
	char path[PATH_MAX + 1];

	strncpy(path, original, sizeof(path));
	if (path[PATH_MAX] != '\0') {
	errno = ENAMETOOLONG;
	return -1;
	}
	end = path + strlen(path);

	for (p = end; p > path;) {

	/* Skip last element */
	while ((--p > path) && (*p != '/'));
	if (p == path) break;

	/* Try realpath() on this subpath */
	*p = '\0';
	r = realpath(path, resolved);
	*p = (p == end) ? '\0' : '/';

	if (r != NULL) {
	/* The subpath has a canonical path */
	break;
	}
	else if (errno == ENOENT \|\| errno == ENOTDIR \|\| errno == EACCES) {
	/* If the lookup of a particular subpath fails because the file
	does not exist, because it is of the wrong type, or because
	access is denied, then remove its last name and try again.
	Other I/O problems cause an error return. */
	continue;
	}
	else {
	return -1;
	}
	}

	if (r != NULL) {
	/* Append unresolved subpath to resolved subpath */
	int rn = strlen(r);
	if (rn + (int)strlen(p) >= len) {
	/* Buffer overflow */
	errno = ENAMETOOLONG;
	return -1;
	}
	if ((rn > 0) && (r[rn - 1] == '/') && (*p == '/')) {
	/* Avoid duplicate slashes */
	p++;
	}
	strcpy(r + rn, p);
	collapse(r);
	return 0;
	}
	else {
	/* Nothing resolved, so just return the original path */
	strcpy(resolved, path);
	collapse(resolved);
	return 0;
	}
	}

	}