_sfopen.c revision 3e14f97f673e8a630f076077de35afdd43dc1587
/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2010 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#include "sfhdr.h"
/* Open a file/string for IO.
** If f is not nil, it is taken as an existing stream that should be
** closed and its structure reused for the new stream.
**
** Written by Kiem-Phong Vo.
*/
#if _BLD_sfio && defined(__EXPORT__)
#define extern __EXPORT__
#endif
extern
#undef extern
#if __STD_C
Sfio_t* _sfopen(Sfio_t* f, const char* file, const char* mode)
#else
Sfio_t* _sfopen(f,file,mode)
Sfio_t* f; /* old stream structure */
char* file; /* file/string to be opened */
char* mode; /* mode of the stream */
#endif
{
int fd, oldfd, oflags, sflags;
SFMTXDECL(f);
/* get the control flags */
if((sflags = _sftype(mode,&oflags,NIL(int*))) == 0)
return NIL(Sfio_t*);
/* changing the control flags */
if(f && !file && !((f->flags|sflags)&SF_STRING) )
{ SFMTXENTER(f, NIL(Sfio_t*));
if(f->mode&SF_INIT ) /* stream uninitialized, ok to set flags */
{ f->flags |= (sflags & (SF_FLAGS & ~SF_RDWR));
if((sflags &= SF_RDWR) != 0) /* reset read/write modes */
{ f->flags = (f->flags & ~SF_RDWR) | sflags;
if((f->flags&SF_RDWR) == SF_RDWR)
f->bits |= SF_BOTH;
else f->bits &= ~SF_BOTH;
if(f->flags&SF_READ)
f->mode = (f->mode&~SF_WRITE)|SF_READ;
else f->mode = (f->mode&~SF_READ)|SF_WRITE;
}
}
else /* make sure there is no buffered data */
{ if(sfsync(f) < 0)
SFMTXRETURN(f,NIL(Sfio_t*));
}
if(f->file >= 0 && (oflags &= (O_TEXT|O_BINARY|O_APPEND)) != 0 )
{ /* set file access control */
int ctl = sysfcntlf(f->file, F_GETFL, 0);
ctl = (ctl & ~(O_TEXT|O_BINARY|O_APPEND)) | oflags;
sysfcntlf(f->file, F_SETFL, ctl);
}
SFMTXRETURN(f,f);
}
if(sflags&SF_STRING)
{ f = sfnew(f,(char*)file,
file ? (size_t)strlen((char*)file) : (size_t)SF_UNBOUND,
-1,sflags);
}
else
{ if(!file)
return NIL(Sfio_t*);
#if _has_oflags /* open the file */
while((fd = sysopenf((char*)file,oflags,SF_CREATMODE)) < 0 && errno == EINTR)
errno = 0;
#else
while((fd = sysopenf(file,oflags&O_ACCMODE)) < 0 && errno == EINTR)
errno = 0;
if(fd >= 0)
{ if((oflags&(O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL) )
{ CLOSE(fd); /* error: file already exists */
return NIL(Sfio_t*);
}
if(oflags&O_TRUNC ) /* truncate file */
{ reg int tf;
while((tf = syscreatf(file,SF_CREATMODE)) < 0 &&
errno == EINTR)
errno = 0;
CLOSE(tf);
}
}
else if(oflags&O_CREAT)
{ while((fd = syscreatf(file,SF_CREATMODE)) < 0 && errno == EINTR)
errno = 0;
if((oflags&O_ACCMODE) != O_WRONLY)
{ /* the file now exists, reopen it for read/write */
CLOSE(fd);
while((fd = sysopenf(file,oflags&O_ACCMODE)) < 0 &&
errno == EINTR)
errno = 0;
}
}
#endif
if(fd < 0)
return NIL(Sfio_t*);
/* we may have to reset the file descriptor to its old value */
oldfd = f ? f->file : -1;
if((f = sfnew(f,NIL(char*),(size_t)SF_UNBOUND,fd,sflags)) && oldfd >= 0)
(void)sfsetfd(f,oldfd);
}
return f;
}
#if __STD_C
int _sftype(reg const char* mode, int* oflagsp, int* uflagp)
#else
int _sftype(mode, oflagsp, uflagp)
reg char* mode;
int* oflagsp;
int* uflagp;
#endif
{
reg int sflags, oflags, uflag;
if(!mode)
return 0;
/* construct the open flags */
sflags = oflags = uflag = 0;
while(1) switch(*mode++)
{
case 'a' :
sflags |= SF_WRITE | SF_APPENDWR;
oflags |= O_WRONLY | O_APPEND | O_CREAT;
continue;
case 'b' :
oflags |= O_BINARY;
continue;
case 'm' :
sflags |= SF_MTSAFE;
uflag = 0;
continue;
case 'r' :
sflags |= SF_READ;
oflags |= O_RDONLY;
continue;
case 's' :
sflags |= SF_STRING;
continue;
case 't' :
oflags |= O_TEXT;
continue;
case 'u' :
sflags &= ~SF_MTSAFE;
uflag = 1;
continue;
case 'w' :
sflags |= SF_WRITE;
oflags |= O_WRONLY | O_CREAT;
if(!(sflags&SF_READ))
oflags |= O_TRUNC;
continue;
case 'x' :
oflags |= O_EXCL;
continue;
case 'F':
/* stdio compatibility -- fd >= FOPEN_MAX (or other magic number) ok */
continue;
case 'W' :
sflags |= SF_WCWIDTH;
uflag = 0;
continue;
case '+' :
if(sflags)
sflags |= SF_READ|SF_WRITE;
continue;
default :
if(!(oflags&O_CREAT) )
oflags &= ~O_EXCL;
#if _WIN32 && !_WINIX
if(!(oflags&(O_BINARY|O_TEXT)))
oflags |= O_BINARY;
#endif
if((sflags&SF_RDWR) == SF_RDWR)
oflags = (oflags&~O_ACCMODE)|O_RDWR;
if(oflagsp)
*oflagsp = oflags;
if(uflagp)
*uflagp = uflag;
if((sflags&(SF_STRING|SF_RDWR)) == SF_STRING)
sflags |= SF_READ;
return sflags;
}
}