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/***********************************************************************
* *
* 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"
/* Function to handle io exceptions.
** Written by Kiem-Phong Vo
*/
#if __STD_C
int _sfexcept(Sfio_t* f, int type, ssize_t io, Sfdisc_t* disc)
#else
int _sfexcept(f,type,io,disc)
Sfio_t* f; /* stream where the exception happened */
int type; /* io type that was performed */
ssize_t io; /* the io return value that indicated exception */
Sfdisc_t* disc; /* discipline in use */
#endif
{
reg int ev, local, lock;
reg ssize_t size;
reg uchar* data;
SFMTXDECL(f);
SFMTXENTER(f,-1);
GETLOCAL(f,local);
lock = f->mode&SF_LOCK;
if(local && io <= 0)
f->flags |= io < 0 ? SF_ERROR : SF_EOF;
if(disc && disc->exceptf)
{ /* let the stream be generally accessible for this duration */
if(local && lock)
SFOPEN(f,0);
/* so that exception handler knows what we are asking for */
_Sfi = f->val = io;
ev = (*(disc->exceptf))(f,type,&io,disc);
/* relock if necessary */
if(local && lock)
SFLOCK(f,0);
if(io > 0 && !(f->flags&SF_STRING) )
SFMTXRETURN(f, ev);
if(ev < 0)
SFMTXRETURN(f, SF_EDONE);
if(ev > 0)
SFMTXRETURN(f, SF_EDISC);
}
if(f->flags&SF_STRING)
{ if(type == SF_READ)
goto chk_stack;
else if(type != SF_WRITE && type != SF_SEEK)
SFMTXRETURN(f, SF_EDONE);
if(local && io >= 0)
{ if(f->size >= 0 && !(f->flags&SF_MALLOC))
goto chk_stack;
/* extend buffer */
if((size = f->size) < 0)
size = 0;
if((io -= size) <= 0)
io = SF_GRAIN;
size = ((size+io+SF_GRAIN-1)/SF_GRAIN)*SF_GRAIN;
if(f->size > 0)
data = (uchar*)realloc((char*)f->data,size);
else data = (uchar*)malloc(size);
if(!data)
goto chk_stack;
f->endb = data + size;
f->next = data + (f->next - f->data);
f->endr = f->endw = f->data = data;
f->size = size;
}
SFMTXRETURN(f, SF_EDISC);
}
if(errno == EINTR)
{ if(_Sfexiting || (f->bits&SF_ENDING) || /* stop being a hero */
(f->flags&SF_IOINTR) ) /* application requests to return */
SFMTXRETURN(f, SF_EDONE);
/* a normal interrupt, we can continue */
errno = 0;
f->flags &= ~(SF_EOF|SF_ERROR);
SFMTXRETURN(f, SF_ECONT);
}
chk_stack:
if(local && f->push &&
((type == SF_READ && f->next >= f->endb) ||
(type == SF_WRITE && f->next <= f->data)))
{ /* pop the stack */
reg Sfio_t *pf;
if(lock)
SFOPEN(f,0);
/* pop and close */
pf = (*_Sfstack)(f,NIL(Sfio_t*));
if((ev = sfclose(pf)) < 0) /* can't close, restack */
(*_Sfstack)(f,pf);
if(lock)
SFLOCK(f,0);
ev = ev < 0 ? SF_EDONE : SF_ESTACK;
}
else ev = SF_EDONE;
SFMTXRETURN(f, ev);
}
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