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

326 lines
10 KiB
C

/***
*tempnam.c - generate unique file name
*
* Copyright (c) 1986-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
*
*Revision History:
* ??-??-?? TC initial version
* 04-17-86 JMB changed directory of last resort from \tmp to tmp.
* eliminated use of L_tmpnam (it was incoorectly defined
* in stdio.h and should not be used in tempnam; see
* System V definition of tempnam.
* 04-23-86 TC changed last try directory from tmp to current directory
* 04-29-86 JMB bug fix: pfxlength was being set from strlen(pfx)
* even if pfx was NULL. Fixed to set pfxlength to zero
* if pfx is NULL, strlen(pfx) otherwise.
* 05-28-86 TC changed stat's to access's, and optimized code a bit
* 12-01-86 JMB added support for Kanji file names until KANJI switch
* 12-15-86 JMB free malloced memory if (++_tmpoff == first)
* 07-15-87 JCR Re-init _tempoff based on length of pfx (fixes infinate
* loop bug; also, tempnam() now uses _tempoff instead of
* _tmpoff (used by tmpnam()).
* 10-16-87 JCR Fixed bug in _tempoff re-init code if pfx is NULL.
* 11-09-87 JCR Multi-thread version
* 12-11-87 JCR Added "_LOAD_DS" to declaration
* 05-27-88 PHG Merged DLL and normal versions
* 06-09-89 GJF Propagated MT's change of 05-17-89 (Kanji)
* 02-16-90 GJF Fixed copyright and indents
* 03-19-90 GJF Replaced _LOAD_DS and _CALLTYPE1 and added #include
* <cruntime.h>.
* 03-26-90 GJF Added #include <io.h>.
* 08-13-90 SBM Compiles cleanly with -W3, replaced explicit register
* declarations by REGn references
* 10-03-90 GJF New-style function declarator.
* 01-21-91 GJF ANSI naming.
* 08-19-91 JCR Allow quotes in TMP variable path
* 08-27-91 JCR ANSI naming
* 08-25-92 GJF Don't build for POSIX.
* 11-30-92 KRS Generalize KANJI support to MBCS. Port 16-bit bug fix.
* 04-06-93 SKS Replace _CRTAPI* with __cdecl
* 12-07-93 CFW Wide char enable.
* 01-10-95 CFW Debug CRT allocs.
* 01-23-95 CFW Debug: tempnam return freed by user.
* 02-21-95 GJF Appended Mac version of source file (somewhat cleaned
* up), with appropriate #ifdef-s. Also replaced WPRFLAG
* with _UNICODE.
* 03-10-95 CFW Made _tempnam() parameters const.
* 03-14-95 JCF Made pfin _TSCHAR for the Mac.
* 07-30-96 GJF Allow longer file names and changed the way we ensure
* a file name is not too long. In particular, this
* corrects the absurdly long loop (appeared infinite to
* to users) which occurred when the user supplied prefix
* was too long. Also, cleaned up the format a bit.
* 03-04-98 GJF Exception-safe locking.
* 01-04-99 GJF Changes for 64-bit size_t.
* 05-17-99 PML Remove all Macintosh support.
* 12-10-00 PML Fix double-free of qptr when _stripquote succeeds but
* result isn't a valid directory (vs7#5416).
* 02-20-01 PML vs7#172586 Avoid _RT_LOCK by preallocating all locks
* that will be required, and returning failure back on
* inability to allocate a lock.
* 07-07-01 BWT Initialize 's' in tempnam - in case the done2 branch is taken,
* 's' must be something reasonable.
*
*******************************************************************************/
#ifndef _POSIX_
#include <cruntime.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <io.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <malloc.h>
#include <string.h>
#include <internal.h>
#include <mtdll.h>
#include <tchar.h>
#include <dbgint.h>
#ifdef _MBCS
#include <mbstring.h>
#endif
/* local tchar */
#ifdef _UNICODE
#define _tP_tmpdir _wP_tmpdir
#else
#define _tP_tmpdir _P_tmpdir
#endif
#ifdef _UNICODE
static wchar_t * _wstripquote (wchar_t *);
#else
static char * _stripquote (char *);
#endif
/***
*_TSCHAR *_tempnam(dir, prefix) - create unique file name
*
*Purpose:
* Create a file name that is unique in the specified directory.
* The semantics of directory specification is as follows:
* Use the directory specified by the TMP environment variable
* if that exists, else use the dir argument if non-NULL, else
* use _P_tmpdir if that directory exists, else use the current
* working directory), else return NULL.
*
*Entry:
* _TSCHAR *dir - directory to be used for temp file if TMP env var
* not set
* _TSCHAR *prefix - user provided prefix for temp file name
*
*Exit:
* returns ptr to constructed file name if successful
* returns NULL if unsuccessful
*
*Exceptions:
*
*******************************************************************************/
_TSCHAR * __cdecl _ttempnam (
const _TSCHAR *dir,
const _TSCHAR *pfx
)
{
REG1 _TSCHAR *ptr;
REG2 unsigned int pfxlength = 0;
_TSCHAR *s = NULL;
_TSCHAR *pfin;
unsigned int first;
unsigned int bufsz;
_TSCHAR * qptr = NULL; /* ptr to TMP path with quotes stripped out */
#ifdef _MT
if ( !_mtinitlocknum( _TMPNAM_LOCK ))
return NULL;
#endif
/* try TMP path */
if ( ( ptr = _tgetenv( _T("TMP") ) ) && ( _taccess( ptr, 0 ) != -1 ) )
dir = ptr;
/* try stripping quotes out of TMP path */
#ifdef _UNICODE
else if ( (ptr != NULL) && (qptr = _wstripquote(ptr)) &&
#else
else if ( (ptr != NULL) && (qptr = _stripquote(ptr)) &&
#endif
(_taccess(qptr, 0) != -1 ) )
dir = qptr;
/* TMP path not available, use alternatives */
else if (!( dir != NULL && ( _taccess( dir, 0 ) != -1 ) ) )
/* do not "simplify" this depends on side effects!! */
{
if ( _taccess( _tP_tmpdir, 0 ) != -1 )
dir = _tP_tmpdir;
else
dir = _T(".");
}
if (pfx)
pfxlength = (unsigned)_tcslen(pfx);
if ( ((bufsz = (unsigned)_tcslen(dir) + pfxlength + 12) > FILENAME_MAX) ||
((s = malloc(bufsz * sizeof(_TSCHAR))) == NULL) )
/* the 12 above allows for a backslash, 10 char temp string and
a null terminator */
{
goto done2;
}
*s = _T('\0');
_tcscat( s, dir );
pfin = (_TSCHAR *)&(dir[ _tcslen( dir ) - 1 ]);
#ifdef _MBCS
if (*pfin == '\\') {
if (pfin != _mbsrchr(dir,'\\'))
/* *pfin is second byte of a double-byte char */
strcat( s, "\\" );
}
else if (*pfin != '/')
strcat( s, "\\" );
#else
if ( ( *pfin != _T('\\') ) && ( *pfin != _T('/') ) )
{
_tcscat( s, _T("\\") );
}
#endif
if ( pfx != NULL )
{
_tcscat( s, pfx );
}
ptr = &s[_tcslen( s )];
/*
Re-initialize _tempoff if necessary. If we don't re-init _tempoff, we
can get into an infinate loop (e.g., (a) _tempoff is a big number on
entry, (b) prefix is a long string (e.g., 8 chars) and all tempfiles
with that prefix exist, (c) _tempoff will never equal first and we'll
loop forever).
[NOTE: To avoid a conflict that causes the same bug as that discussed
above, _tempnam() uses _tempoff; tmpnam() uses _tmpoff]
*/
#ifdef _MT
_mlock(_TMPNAM_LOCK); /* Lock access to _old_pfxlen and _tempoff */
__try {
#endif
if (_old_pfxlen < pfxlength)
_tempoff = 1;
_old_pfxlen = pfxlength;
first = _tempoff;
do {
if ( (++_tempoff - first) > TMP_MAX ) {
free(s);
s = NULL;
goto done1;
}
/* the maximum length string returned by _ultot is 10 chars
(assuming 32-bit unsigned long) so there is enough room in
the tail of s (pointed to by ptr) for it */
_ultot( (unsigned long)_tempoff, ptr, 10 );
}
while ( (_taccess( s, 0 ) == 0 ) || (errno == EACCES) );
/* Common return */
done1:
#ifdef _MT
; }
__finally {
_munlock(_TMPNAM_LOCK); /* release tempnam lock */
}
#endif
done2:
_free_crt(qptr); /* free temp ptr, if non-NULL */
return(s);
}
/***
*_stripquote() - Strip quotes out of a string
*
*Purpose:
* This routine strips quotes out of a string. This is necessary
* in the case where a file/path name has embedded quotes (i.e.,
* new file system.)
*
* For example,
* c:\tmp\"a b c"\d --> c:\tmp\a b d\d
*
* NOTE: This routine makes a copy of the string since it may be
* passed a pointer to an environment variable that shouldn't be
* changed. It is up to the caller to free up the memory (if the
* return value is non-NULL).
*
*Entry:
* _TSCHAR * ptr = pointer to string
*
*Exit:
* _TSCHAR * ptr = pointer to copy of string with quotes gone.
* NULL = no quotes in string.
*
*Exceptions:
*
*******************************************************************************/
#ifdef _UNICODE
static wchar_t * _wstripquote (
#else
static char * _stripquote (
#endif
_TSCHAR * src
)
{
_TSCHAR * dst;
_TSCHAR * ret;
unsigned int q = 0;
/* get a buffer for the new string */
if ((dst = _malloc_crt((_tcslen(src)+1) * sizeof(_TSCHAR))) == NULL)
return(NULL);
/* copy the string stripping out the quotes */
ret = dst; /* save base ptr */
while (*src) {
if (*src == _T('\"')) {
src++; q++;
}
else
*dst++ = *src++;
}
if (q) {
*dst = _T('\0'); /* final nul */
return(ret);
}
else {
_free_crt(ret);
return(NULL);
}
}
#endif /* _POSIX_ */