windows-nt/Source/XPSP1/NT/base/crts/crtw32/misc/searchen.c
2020-09-26 16:20:57 +08:00

150 lines
5.2 KiB
C

/***
*searchenv.c - find a file using paths from an environment variable
*
* Copyright (c) 1987-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* to search a set a directories specified by an environment variable
* for a specified file name. If found the full path name is returned.
*
*Revision History:
* 06-15-87 DFW initial implementation
* 08-06-87 JCR Changed directory delimeter from '/' to '\'.
* 09-24-87 JCR Removed 'const' from declarations (caused cl warnings).
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 02-17-88 JCR Added 'const' copy_path local to get rid of cl warning.
* 07-19-88 SKS Fixed bug if root directory is current directory
* 08-03-89 JCR Allow quoted strings in file/path names
* 08-29-89 GJF Changed copy_path() to _getpath() and moved it to it's
* own source file. Also fixed handling of multiple semi-
* colons.
* 11-20-89 GJF Added const attribute to types of fname and env_var.
* 03-15-90 GJF Replaced _LOAD_DS with _CALLTYPE1 and added #include
* <cruntime.h>. Also, cleaned up the formatting a bit.
* 07-25-90 SBM Removed redundant include (stdio.h)
* 10-04-90 GJF New-style function declarator.
* 01-22-91 GJF ANSI naming.
* 08-26-92 GJF Include unistd.h for POSIX build.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 12-07-93 CFW Wide char enable.
* 01-31-95 GJF Use _fullpath instead of _getcwd, to convert a file
* that exists relative to the current directory, to a
* fully qualified path.
* 02-16-95 JWM Mac merge.
* 03-29-95 BWT Fix POSIX build by sticking with getcwd.
* 10-20-95 GJF Use local buffer instead of the caller's buffer to
* build the pathname (Olympus0 9336).
* 05-17-99 PML Remove all Macintosh support.
*
*******************************************************************************/
#include <cruntime.h>
#ifdef _POSIX_
#include <unistd.h>
#else
#include <direct.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <io.h>
#include <internal.h>
#include <tchar.h>
/***
*_searchenv() - search for file along paths from environment variable
*
*Purpose:
* to search for a specified file in the directory(ies) specified by
* a given environment variable, and, if found, to return the full
* path name of the file. The file is first looked for in the current
* working directory, prior to looking in the paths specified by env_var.
*
*Entry:
* fname - name of file to search for
* env_var - name of environment variable to use for paths
* path - pointer to storage for the constructed path name
*
*Exit:
* path - pointer to constructed path name, if the file is found, otherwise
* it points to the empty string.
*
*Exceptions:
*
*******************************************************************************/
void __cdecl _tsearchenv (
const _TSCHAR *fname,
const _TSCHAR *env_var,
_TSCHAR *path
)
{
register _TSCHAR *p;
register int c;
_TSCHAR *env_p;
size_t len;
_TSCHAR pathbuf[_MAX_PATH + 4];
if (_taccess(fname, 0) == 0) {
#if !defined(_POSIX_)
/* exists, convert it to a fully qualified pathname and
return */
if ( _tfullpath(path, fname, _MAX_PATH) == NULL )
*path = _T('\0');
#else /* !_POSIX_ */
/* exists in this directory - get cwd and concatenate file
name */
#if defined(_POSIX_)
if (getcwd(path, _MAX_PATH))
#else
if (_tgetcwd(path, _MAX_PATH))
#endif
{
_tcscat(path, fname);
}
#endif /* !_POSIX_ */
return;
}
if ((env_p = _tgetenv(env_var)) == NULL) {
/* no such environment var. and not in cwd, so return empty
string */
*path = _T('\0');
return;
}
#ifdef _UNICODE
while ( (env_p = _wgetpath(env_p, pathbuf, _MAX_PATH)) && *pathbuf ) {
#else
while ( (env_p = _getpath(env_p, pathbuf, _MAX_PATH)) && *pathbuf ) {
#endif
/* path now holds nonempty pathname from env_p, concatenate
the file name and go */
len = _tcslen(pathbuf);
p = pathbuf + len;
if ( ((c = *(p - 1)) != _T('/')) && (c != _T('\\')) &&
(c != _T(':')) )
{
/* add a trailing '\' */
*p++ = _T('\\');
len++;
}
/* p now points to character following trailing '/', '\'
or ':' */
if ( (len + _tcslen(fname)) <= _MAX_PATH ) {
_tcscpy(p, fname);
if ( _taccess(pathbuf, 0) == 0 ) {
/* found a match, copy the full pathname into the caller's
buffer */
_tcscpy(path, pathbuf);
return;
}
}
}
/* if we get here, we never found it, return empty string */
*path = _T('\0');
}