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pool_path.c
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pool_path.c
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/* -*-pgsql-c-*- */
/*
*
* $Header: /cvsroot/pgpool/pgpool-II/pool_path.c,v 1.3 2009/08/22 04:04:21 t-ishii Exp $
*
* pgpool: a language independent connection pool server for PostgreSQL
* written by Tatsuo Ishii
*
* Portions Copyright (c) 2003-2008, PgPool Global Development Group
* Portions Copyright (c) 2004, PostgreSQL Global Development Group
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that the above copyright notice appear in all
* copies and that both that copyright notice and this permission
* notice appear in supporting documentation, and that the name of the
* author not be used in advertising or publicity pertaining to
* distribution of the software without specific, written prior
* permission. The author makes no representations about the
* suitability of this software for any purpose. It is provided "as
* is" without express or implied warranty.
*
* pool_path.c.: small functions to manipulate paths
*
*/
#include "pool_type.h"
#include "pool_path.h"
#include <stdio.h>
#include <string.h>
static void trim_directory(char *path);
static void trim_trailing_separator(char *path);
/*
* get_parent_directory
*
* Modify the given string in-place to name the parent directory of the
* named file.
*/
void get_parent_directory(char *path)
{
trim_directory(path);
}
/*
* trim_directory
*
* Trim trailing directory from path, that is, remove any trailing slashes,
* the last pathname component, and the slash just ahead of it --- but never
* remove a leading slash.
*/
static void trim_directory(char *path)
{
char *p;
if (path[0] == '\0')
return;
/* back up over trailing slash(es) */
for (p = path + strlen(path) - 1; IS_DIR_SEP(*p) && p > path; p--);
/* back up over directory name */
for (; !IS_DIR_SEP(*p) && p > path; p--);
/* if multiple slashes before directory name, remove 'em all */
for (; p > path && IS_DIR_SEP(*(p - 1)); p--);
/* don't erase a leading slash */
if (p == path && IS_DIR_SEP(*p))
p++;
*p = '\0';
}
/*
* join_path_components - join two path components, inserting a slash
*
* ret_path is the output area (must be of size MAXPGPATH)
*
* ret_path can be the same as head, but not the same as tail.
*/
void join_path_components(char *ret_path, const char *head, const char *tail)
{
if (ret_path != head)
StrNCpy(ret_path, head, MAXPGPATH);
/*
* Remove any leading "." and ".." in the tail component,
* adjusting head as needed.
*/
for (;;)
{
if (tail[0] == '.' && IS_DIR_SEP(tail[1]))
{
tail += 2;
}
else if (tail[0] == '.' && tail[1] == '\0')
{
tail += 1;
break;
}
else if (tail[0] == '.' && tail[1] == '.' && IS_DIR_SEP(tail[2]))
{
trim_directory(ret_path);
tail += 3;
}
else if (tail[0] == '.' && tail[1] == '.' && tail[2] == '\0')
{
trim_directory(ret_path);
tail += 2;
break;
}
else
break;
}
if (*tail)
snprintf(ret_path + strlen(ret_path), MAXPGPATH - strlen(ret_path), "/%s", tail);
}
/*
* Clean up path by:
* o remove trailing slash
* o remove duplicate adjacent separators
* o remove trailing '.'
* o process trailing '..' ourselves
*/
void canonicalize_path(char *path)
{
char *p, *to_p;
bool was_sep = false;
/*
* Removing the trailing slash on a path means we never get ugly
* double trailing slashes.
*/
trim_trailing_separator(path);
/*
* Remove duplicate adjacent separators
*/
p = path;
to_p = p;
for (; *p; p++, to_p++)
{
/* Handle many adjacent slashes, like "/a///b" */
while (*p == '/' && was_sep)
p++;
if (to_p != p)
*to_p = *p;
was_sep = (*p == '/');
}
*to_p = '\0';
/*
* Remove any trailing uses of "." and process ".." ourselves
*/
for (;;)
{
int len = strlen(path);
if (len > 2 && strcmp(path + len - 2, "/.") == 0)
trim_directory(path);
else if (len > 3 && strcmp(path + len - 3, "/..") == 0)
{
trim_directory(path);
trim_directory(path);
/* remove directory above */
}
else
break;
}
}
/*
* trim_trailing_separator
*
* trim off trailing slashes, but not a leading slash
*/
static void trim_trailing_separator(char *path)
{
char *p;
p = path + strlen(path);
if (p > path)
for (p--; p > path && IS_DIR_SEP(*p); p--)
*p = '\0';
}