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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 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"
/* Internal function to do a hard read.
** This knows about discipline and memory mapping, peek read.
**
** Written by Kiem-Phong Vo.
*/
/* synchronize unseekable write streams */
#if __STD_C
static void _sfwrsync(void)
#else
static void _sfwrsync()
#endif
{ reg Sfpool_t* p;
reg Sfio_t* f;
reg int n;
/* sync all pool heads */
for(p = _Sfpool.next; p; p = p->next)
{ if(p->n_sf <= 0)
continue;
f = p->sf[0];
if(!SFFROZEN(f) && f->next > f->data &&
(f->mode&SF_WRITE) && f->extent < 0 )
(void)_sfflsbuf(f,-1);
}
/* and all the ones in the discrete pool */
for(n = 0; n < _Sfpool.n_sf; ++n)
{ f = _Sfpool.sf[n];
if(!SFFROZEN(f) && f->next > f->data &&
(f->mode&SF_WRITE) && f->extent < 0 )
(void)_sfflsbuf(f,-1);
}
}
#if __STD_C
ssize_t sfrd(Sfio_t* f, Void_t* buf, size_t n, Sfdisc_t* disc)
#else
ssize_t sfrd(f,buf,n,disc)
Sfio_t* f;
Void_t* buf;
size_t n;
Sfdisc_t* disc;
#endif
{
Sfoff_t r;
reg Sfdisc_t* dc;
reg int local, rcrv, dosync, oerrno;
SFMTXDECL(f);
SFMTXENTER(f,-1);
GETLOCAL(f,local);
if((rcrv = f->mode & (SF_RC|SF_RV)) )
f->mode &= ~(SF_RC|SF_RV);
f->bits &= ~SF_JUSTSEEK;
if(f->mode&SF_PKRD)
SFMTXRETURN(f, -1);
if(!local && !(f->bits&SF_DCDOWN)) /* an external user's call */
{ if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
SFMTXRETURN(f, -1);
if(f->next < f->endb)
{ if(SFSYNC(f) < 0)
SFMTXRETURN(f, -1);
if((f->mode&(SF_SYNCED|SF_READ)) == (SF_SYNCED|SF_READ) )
{ f->endb = f->next = f->endr = f->data;
f->mode &= ~SF_SYNCED;
}
#ifdef MAP_TYPE
if((f->bits&SF_MMAP) && f->data)
{ SFMUNMAP(f, f->data, f->endb-f->data);
f->data = NIL(uchar*);
}
#endif
f->next = f->endb = f->endr = f->endw = f->data;
}
}
for(dosync = 0;;)
{ /* stream locked by sfsetfd() */
if(!(f->flags&SF_STRING) && f->file < 0)
SFMTXRETURN(f, 0);
f->flags &= ~(SF_EOF|SF_ERROR);
dc = disc;
if(f->flags&SF_STRING)
{ if((r = (f->data+f->extent) - f->next) < 0)
r = 0;
if(r <= 0)
goto do_except;
SFMTXRETURN(f, (ssize_t)r);
}
/* warn that a read is about to happen */
SFDISC(f,dc,readf);
if(dc && dc->exceptf && (f->flags&SF_IOCHECK) )
{ reg int rv;
if(local)
SETLOCAL(f);
if((rv = _sfexcept(f,SF_READ,n,dc)) > 0)
n = rv;
else if(rv < 0)
{ f->flags |= SF_ERROR;
SFMTXRETURN(f, (ssize_t)rv);
}
}
#ifdef MAP_TYPE
if(f->bits&SF_MMAP)
{ reg ssize_t a, round;
sfstat_t st;
/* determine if we have to copy data to buffer */
if((uchar*)buf >= f->data && (uchar*)buf <= f->endb)
{ n += f->endb - f->next;
buf = NIL(char*);
}
/* actual seek location */
if((f->flags&(SF_SHARE|SF_PUBLIC)) == (SF_SHARE|SF_PUBLIC) &&
(r = SFSK(f,(Sfoff_t)0,SEEK_CUR,dc)) != f->here)
f->here = r;
else f->here -= f->endb-f->next;
/* before mapping, make sure we have data to map */
if((f->flags&SF_SHARE) || (size_t)(r = f->extent-f->here) < n)
{ if((r = sysfstatf(f->file,&st)) < 0)
goto do_except;
if((r = (f->extent = st.st_size) - f->here) <= 0 )
{ r = 0; /* eof */
goto do_except;
}
}
/* make sure current position is page aligned */
if((a = (size_t)(f->here%_Sfpage)) != 0)
{ f->here -= a;
r += a;
}
/* map minimal requirement */
if(r > (round = (1 + (n+a)/f->size)*f->size) )
r = round;
if(f->data)
SFMUNMAP(f, f->data, f->endb-f->data);
for(;;)
{ f->data = (uchar*) sysmmapf((caddr_t)0, (size_t)r,
(PROT_READ|PROT_WRITE),
MAP_PRIVATE,
f->file, (sfoff_t)f->here);
if(f->data && (caddr_t)f->data != (caddr_t)(-1))
break;
else
{ f->data = NIL(uchar*);
if((r >>= 1) < (_Sfpage*SF_NMAP) ||
(errno != EAGAIN && errno != ENOMEM) )
break;
}
}
if(f->data)
{ if(f->bits&SF_SEQUENTIAL)
SFMMSEQON(f,f->data,r);
f->next = f->data+a;
f->endr = f->endb = f->data+r;
f->endw = f->data;
f->here += r;
/* make known our seek location */
(void)SFSK(f,f->here,SEEK_SET,dc);
if(buf)
{ if(n > (size_t)(r-a))
n = (ssize_t)(r-a);
memcpy(buf,f->next,n);
f->next += n;
}
else n = f->endb - f->next;
SFMTXRETURN(f, n);
}
else
{ r = -1;
f->here += a;
/* reset seek pointer to its physical location */
(void)SFSK(f,f->here,SEEK_SET,dc);
/* make a buffer */
(void)SFSETBUF(f,(Void_t*)f->tiny,(size_t)SF_UNBOUND);
if(!buf)
{ buf = (Void_t*)f->data;
n = f->size;
}
}
}
#endif
/* sync unseekable write streams to prevent deadlock */
if(!dosync && f->extent < 0)
{ dosync = 1;
_sfwrsync();
}
/* make sure file pointer is right */
if(f->extent >= 0 && (f->flags&SF_SHARE) )
{ if(!(f->flags&SF_PUBLIC) )
f->here = SFSK(f,f->here,SEEK_SET,dc);
else f->here = SFSK(f,(Sfoff_t)0,SEEK_CUR,dc);
}
oerrno = errno;
errno = 0;
if(dc && dc->readf)
{ int share = f->flags&SF_SHARE;
if(rcrv) /* pass on rcrv for possible continuations */
f->mode |= rcrv;
/* tell readf that no peeking necessary */
else f->flags &= ~SF_SHARE;
SFDCRD(f,buf,n,dc,r);
/* reset flags */
if(rcrv)
f->mode &= ~rcrv;
else f->flags |= share;
}
else if(SFISNULL(f))
r = 0;
else if(f->extent < 0 && (f->flags&SF_SHARE) && rcrv)
{ /* try peek read */
r = sfpkrd(f->file, (char*)buf, n,
(rcrv&SF_RC) ? (int)f->getr : -1,
-1L, (rcrv&SF_RV) ? 1 : 0);
if(r > 0)
{ if(rcrv&SF_RV)
f->mode |= SF_PKRD;
else f->mode |= SF_RC;
}
}
else r = sysreadf(f->file,buf,n);
if(errno == 0 )
errno = oerrno;
if(r > 0 )
{ if(!(f->bits&SF_DCDOWN) ) /* not a continuation call */
{ if(!(f->mode&SF_PKRD) )
{ f->here += r;
if(f->extent >= 0 && f->extent < f->here)
f->extent = f->here;
}
if((uchar*)buf >= f->data &&
(uchar*)buf < f->data+f->size)
f->endb = f->endr = ((uchar*)buf) + r;
}
SFMTXRETURN(f, (ssize_t)r);
}
do_except:
if(local)
SETLOCAL(f);
switch(_sfexcept(f,SF_READ,(ssize_t)r,dc))
{
case SF_ECONT :
goto do_continue;
case SF_EDONE :
n = local ? 0 : (ssize_t)r;
SFMTXRETURN(f,n);
case SF_EDISC :
if(!local && !(f->flags&SF_STRING))
goto do_continue;
/* else fall thru */
case SF_ESTACK :
SFMTXRETURN(f, -1);
}
do_continue:
for(dc = f->disc; dc; dc = dc->disc)
if(dc == disc)
break;
disc = dc;
}
}
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