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/* files.cxx
$Id: files.cxx,v 1.11 2002/01/17 06:24:29 elf Exp $
written by Oscar Levi
10 December 1998
This file is part of the project BSIGN. See the file README for
more information.
Copyright (C) 1998 The Buici Company.
This program 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 of the License, or
(at your option) any later version.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
-----------
DESCRIPTION
-----------
Simple routines for manipulating files in the filesystem.
*/
#include "standard.h"
#include "sys/stat.h"
#include "sys/types.h"
#include "limits.h"
#include "utime.h"
#include "errno.h"
#include "files.h"
/* dup_status
copies the status of one file to another. This is meant to
replicate the ownership and permissions of the file.
When chmod is before chown and we are attempting to set the setuid
bit, the chown call clears that bit. Transposing these calls makes
it work properly.
*/
bool dup_status (const char* szFileNew, const char* szFile)
{
struct stat st;
if (::stat (szFile, &st))
return false;
struct utimbuf t;
t.actime = st.st_atime;
t.modtime = st.st_mtime;
if (utime (szFileNew, &t))
return false;
if (chown (szFileNew, st.st_uid, st.st_gid))
return false;
if (chmod (szFileNew, st.st_mode))
return false;
return true;
}
#if 0
/* is_file
returns true if the named file is a regular file or a link to a
regular file.
*/
bool is_file (const char* szPath)
{
struct stat st;
memset (&st, 0, sizeof (struct stat));
if (stat (szPath, &st))
return false;
return S_ISREG (st.st_mode);
}
/* is_symlink
returns true of the last component of szPath is a symbolic link.
Directory components that are symbolic links are not detected.
*/
bool is_symlink (const char* szPath)
{
struct stat st;
memset (&st, 0, sizeof (struct stat));
if (lstat (szPath, &st))
return false;
return S_ISLNK (st.st_mode);
}
#endif
char* path_of (const char* szPathOriginal)
{
char* sz = resolve_link (szPathOriginal);
if (!sz) { // No link to resolve
sz = new char [strlen (szPathOriginal) + 3];
strcpy (sz, szPathOriginal);
}
char* pch = rindex (sz, '/');
if (!pch) {
strcpy (sz, ".");
return sz;
}
*pch = 0;
return sz;
}
char* resolve_link (const char* szPathOriginal)
{
if (!szPathOriginal || !*szPathOriginal
|| strlen (szPathOriginal) >= PATH_MAX)
return NULL;
static char szPath[PATH_MAX];
strcpy (szPath, szPathOriginal);
struct stat st;
// Find where the link really points
do {
memset (&st, 0, sizeof (struct stat));
if (lstat (szPath, &st))
return NULL;
if (S_ISLNK (st.st_mode)) {
static char sz[PATH_MAX + 1];
int cb = readlink (szPath, sz, sizeof (sz) - 1);
if (cb == -1)
return NULL;
sz[cb] = 0;
if (*sz == '/') // Absolute path link
strcpy (szPath, sz);
else { // Relative path link
if (strlen (szPath) + strlen (sz) >= PATH_MAX)
return NULL;
char* pch = rindex (szPath, '/');
strcpy (pch ? (pch + 1) : szPath, sz);
}
}
} while (S_ISLNK (st.st_mode));
char* sz = new char[strlen (szPath) + 1];
strcpy (sz, szPath);
return sz;
}
/* replace_file
function for replacing the old file with the new one. Because we
create our temporary output file in the same directory as the
output target, it is extremely improbably that we will not be able
to replace the old file with the new. This function guarantees
that at no time will the old file be deleted before the new file
replaces it.
*/
bool replace_file (const char* szFileOutputOriginal, const char* szFile)
{
char* szFileOutput = resolve_link (szFileOutputOriginal);
if (!szFileOutput) // Link resolution error
return false;
int result = rename (szFile, szFileOutput); // One step replacement
free (szFileOutput);
return result == 0;
}
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