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/* pathcanon.c -- Canonicalize and manipulate pathnames. */
/* Copyright (C) 2000 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne Again SHell.
Bash is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
Bash 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
for more details.
You should have received a copy of the GNU General Public License along
with Bash; see the file COPYING. If not, write to the Free Software
Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
#include <config.h>
#include <bashtypes.h>
#ifndef _MINIX
# include <sys/param.h>
#endif
#include <posixstat.h>
#if defined (HAVE_UNISTD_H)
# include <unistd.h>
#endif
#include <filecntl.h>
#include <bashansi.h>
#include <stdio.h>
#include <chartypes.h>
#include "shell.h"
/* Return 1 if PATH corresponds to a directory. A function for debugging. */
static int
_path_isdir (path)
char *path;
{
int l;
struct stat sb;
l = stat (path, &sb) == 0 && S_ISDIR (sb.st_mode);
return l;
}
/* Canonicalize PATH, and return a new path. The new path differs from PATH
in that:
Multple `/'s are collapsed to a single `/'.
Leading `./'s and trailing `/.'s are removed.
Trailing `/'s are removed.
Non-leading `../'s and trailing `..'s are handled by removing
portions of the path. */
/* Look for ROOTEDPATH, PATHSEP, DIRSEP, and ISDIRSEP in ../../general.h */
#define DOUBLE_SLASH(p) ((p[0] == '/') && (p[1] == '/') && p[2] != '/')
char *
sh_canonpath (path, flags)
char *path;
int flags;
{
char stub_char;
char *result, *p, *q, *base, *dotdot;
int rooted, double_slash_path;
/* The result cannot be larger than the input PATH. */
result = (flags & PATH_NOALLOC) ? path : savestring (path);
/* POSIX.2 says to leave a leading `//' alone. On cygwin, we skip over any
leading `x:' (dos drive name). */
if (rooted = ROOTEDPATH(path))
{
stub_char = DIRSEP;
#if defined (__CYGWIN__)
base = (ISALPHA((unsigned char)result[0]) && result[1] == ':') ? result + 3 : result + 1;
#else
base = result + 1;
#endif
double_slash_path = DOUBLE_SLASH (path);
base += double_slash_path;
}
else
{
stub_char = '.';
#if defined (__CYGWIN__)
base = (ISALPHA((unsigned char)result[0]) && result[1] == ':') ? result + 2 : result;
#else
base = result;
#endif
double_slash_path = 0;
}
/*
* invariants:
* base points to the portion of the path we want to modify
* p points at beginning of path element we're considering.
* q points just past the last path element we wrote (no slash).
* dotdot points just past the point where .. cannot backtrack
* any further (no slash).
*/
p = q = dotdot = base;
while (*p)
{
if (ISDIRSEP(p[0])) /* null element */
p++;
else if(p[0] == '.' && PATHSEP(p[1])) /* . and ./ */
p += 1; /* don't count the separator in case it is nul */
else if (p[0] == '.' && p[1] == '.' && PATHSEP(p[2])) /* .. and ../ */
{
p += 2; /* skip `..' */
if (q > dotdot) /* can backtrack */
{
if (flags & PATH_CHECKDOTDOT)
{
char c;
/* Make sure what we have so far corresponds to a valid
path before we chop some of it off. */
c = *q;
*q = '\0';
if (_path_isdir (result) == 0)
{
if ((flags & PATH_NOALLOC) == 0)
free (result);
return ((char *)NULL);
}
*q = c;
}
while (--q > dotdot && ISDIRSEP(*q) == 0)
;
}
else if (rooted == 0)
{
/* /.. is / but ./../ is .. */
if (q != base)
*q++ = DIRSEP;
*q++ = '.';
*q++ = '.';
dotdot = q;
}
}
else /* real path element */
{
/* add separator if not at start of work portion of result */
if (q != base)
*q++ = DIRSEP;
while (*p && (ISDIRSEP(*p) == 0))
*q++ = *p++;
/* Check here for a valid directory with _path_isdir. */
if (flags & PATH_CHECKEXISTS)
{
char c;
/* Make sure what we have so far corresponds to a valid
path before we chop some of it off. */
c = *q;
*q = '\0';
if (_path_isdir (result) == 0)
{
if ((flags & PATH_NOALLOC) == 0)
free (result);
return ((char *)NULL);
}
*q = c;
}
}
}
/* Empty string is really ``.'' or `/', depending on what we started with. */
if (q == result)
*q++ = stub_char;
*q = '\0';
/* If the result starts with `//', but the original path does not, we
can turn the // into /. Because of how we set `base', this should never
be true, but it's a sanity check. */
if (DOUBLE_SLASH(result) && double_slash_path == 0)
{
if (result[2] == '\0') /* short-circuit for bare `//' */
result[1] = '\0';
else
strcpy (result, result + 1);
}
return (result);
}
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