1N/A/***********************************************************************
1N/A* *
1N/A* This software is part of the ast package *
1N/A* Copyright (c) 1985-2011 AT&T Intellectual Property *
1N/A* and is licensed under the *
1N/A* Common Public License, Version 1.0 *
1N/A* by AT&T Intellectual Property *
1N/A* *
1N/A* A copy of the License is available at *
1N/A* http://www.opensource.org/licenses/cpl1.0.txt *
1N/A* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
1N/A* *
1N/A* Information and Software Systems Research *
1N/A* AT&T Research *
1N/A* Florham Park NJ *
1N/A* *
1N/A* Glenn Fowler <gsf@research.att.com> *
1N/A* David Korn <dgk@research.att.com> *
1N/A* Phong Vo <kpv@research.att.com> *
1N/A* *
1N/A***********************************************************************/
1N/A#include "sfhdr.h"
1N/A
1N/A/* Write with discipline.
1N/A**
1N/A** Written by Kiem-Phong Vo.
1N/A*/
1N/A
1N/A/* hole preserving writes */
1N/A#if __STD_C
1N/Astatic ssize_t sfoutput(Sfio_t* f, char* buf, size_t n)
1N/A#else
1N/Astatic ssize_t sfoutput(f,buf,n)
1N/ASfio_t* f;
1N/Achar* buf;
1N/Asize_t n;
1N/A#endif
1N/A{ reg char *sp, *wbuf, *endbuf;
1N/A reg ssize_t s, w, wr;
1N/A
1N/A s = w = 0;
1N/A wbuf = buf;
1N/A endbuf = buf+n;
1N/A while(n > 0)
1N/A { if((ssize_t)n < _Sfpage) /* no hole possible */
1N/A { buf += n;
1N/A s = n = 0;
1N/A }
1N/A else while((ssize_t)n >= _Sfpage)
1N/A { /* see if a hole of 0's starts here */
1N/A sp = buf+1;
1N/A if(buf[0] == 0 && buf[_Sfpage-1] == 0)
1N/A { /* check byte at a time until int-aligned */
1N/A while(((ulong)sp)%sizeof(int))
1N/A { if(*sp != 0)
1N/A goto chk_hole;
1N/A sp += 1;
1N/A }
1N/A
1N/A /* check using int to speed up */
1N/A while(sp < endbuf)
1N/A { if(*((int*)sp) != 0)
1N/A goto chk_hole;
1N/A sp += sizeof(int);
1N/A }
1N/A
1N/A /* check the remaining bytes */
1N/A if(sp > endbuf)
1N/A { sp -= sizeof(int);
1N/A while(sp < endbuf)
1N/A { if(*sp != 0)
1N/A goto chk_hole;
1N/A sp += 1;
1N/A }
1N/A }
1N/A }
1N/A
1N/A chk_hole:
1N/A if((s = sp-buf) >= _Sfpage) /* found a hole */
1N/A break;
1N/A
1N/A /* skip a dirty page */
1N/A n -= _Sfpage;
1N/A buf += _Sfpage;
1N/A }
1N/A
1N/A /* write out current dirty pages */
1N/A if(buf > wbuf)
1N/A { if((ssize_t)n < _Sfpage)
1N/A { buf = endbuf;
1N/A n = s = 0;
1N/A }
1N/A if((wr = syswritef(f->file,wbuf,buf-wbuf)) > 0)
1N/A { w += wr;
1N/A f->bits &= ~SF_HOLE;
1N/A }
1N/A if(wr != (buf-wbuf))
1N/A break;
1N/A wbuf = buf;
1N/A }
1N/A
1N/A /* seek to a rounded boundary within the hole */
1N/A if(s >= _Sfpage)
1N/A { s = (s/_Sfpage)*_Sfpage;
1N/A if(SFSK(f,(Sfoff_t)s,SEEK_CUR,NIL(Sfdisc_t*)) < 0)
1N/A break;
1N/A w += s;
1N/A n -= s;
1N/A wbuf = (buf += s);
1N/A f->bits |= SF_HOLE;
1N/A
1N/A if(n > 0)
1N/A { /* next page must be dirty */
1N/A s = (ssize_t)n <= _Sfpage ? 1 : _Sfpage;
1N/A buf += s;
1N/A n -= s;
1N/A }
1N/A }
1N/A }
1N/A
1N/A return w > 0 ? w : -1;
1N/A}
1N/A
1N/A#if __STD_C
1N/Assize_t sfwr(Sfio_t* f, const Void_t* buf, size_t n, Sfdisc_t* disc)
1N/A#else
1N/Assize_t sfwr(f,buf,n,disc)
1N/ASfio_t* f;
1N/AVoid_t* buf;
1N/Asize_t n;
1N/ASfdisc_t* disc;
1N/A#endif
1N/A{
1N/A reg ssize_t w;
1N/A reg Sfdisc_t* dc;
1N/A reg int local, oerrno;
1N/A SFMTXDECL(f);
1N/A
1N/A SFMTXENTER(f,(ssize_t)(-1));
1N/A
1N/A GETLOCAL(f,local);
1N/A if(!local && !(f->bits&SF_DCDOWN)) /* an external user's call */
1N/A { if(f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0 )
1N/A SFMTXRETURN(f, (ssize_t)(-1));
1N/A if(f->next > f->data && SFSYNC(f) < 0 )
1N/A SFMTXRETURN(f, (ssize_t)(-1));
1N/A }
1N/A
1N/A for(;;)
1N/A { /* stream locked by sfsetfd() */
1N/A if(!(f->flags&SF_STRING) && f->file < 0)
1N/A SFMTXRETURN(f,(ssize_t)0);
1N/A
1N/A /* clear current error states */
1N/A f->flags &= ~(SF_EOF|SF_ERROR);
1N/A
1N/A dc = disc;
1N/A if(f->flags&SF_STRING) /* total required buffer */
1N/A w = n + (f->next - f->data);
1N/A else
1N/A { /* warn that a write is about to happen */
1N/A SFDISC(f,dc,writef);
1N/A if(dc && dc->exceptf && (f->flags&SF_IOCHECK) )
1N/A { reg int rv;
1N/A if(local)
1N/A SETLOCAL(f);
1N/A if((rv = _sfexcept(f,SF_WRITE,n,dc)) > 0)
1N/A n = rv;
1N/A else if(rv < 0)
1N/A { f->flags |= SF_ERROR;
1N/A SFMTXRETURN(f, rv);
1N/A }
1N/A }
1N/A
1N/A if(f->extent >= 0)
1N/A { /* make sure we are at the right place to write */
1N/A if(f->flags&SF_APPENDWR)
1N/A { if(f->here != f->extent || (f->flags&SF_SHARE))
1N/A { f->here = SFSK(f,(Sfoff_t)0,SEEK_END,dc);
1N/A f->extent = f->here;
1N/A }
1N/A }
1N/A else if((f->flags&SF_SHARE) && !(f->flags&SF_PUBLIC))
1N/A f->here = SFSK(f,f->here,SEEK_SET,dc);
1N/A }
1N/A
1N/A oerrno = errno;
1N/A errno = 0;
1N/A
1N/A if(dc && dc->writef)
1N/A { SFDCWR(f,buf,n,dc,w);
1N/A }
1N/A else if(SFISNULL(f))
1N/A w = n;
1N/A else if(f->flags&SF_WHOLE)
1N/A goto do_write;
1N/A else if((ssize_t)n >= _Sfpage &&
1N/A !(f->flags&(SF_SHARE|SF_APPENDWR)) &&
1N/A f->here == f->extent && (f->here%_Sfpage) == 0)
1N/A { if((w = sfoutput(f,(char*)buf,n)) <= 0)
1N/A goto do_write;
1N/A }
1N/A else
1N/A {
1N/A do_write:
1N/A if((w = syswritef(f->file,buf,n)) > 0)
1N/A f->bits &= ~SF_HOLE;
1N/A }
1N/A
1N/A if(errno == 0)
1N/A errno = oerrno;
1N/A
1N/A if(w > 0)
1N/A { if(!(f->bits&SF_DCDOWN) )
1N/A { if((f->flags&(SF_APPENDWR|SF_PUBLIC)) && f->extent >= 0 )
1N/A f->here = SFSK(f,(Sfoff_t)0,SEEK_CUR,dc);
1N/A else f->here += w;
1N/A if(f->extent >= 0 && f->here > f->extent)
1N/A f->extent = f->here;
1N/A }
1N/A
1N/A SFMTXRETURN(f, (ssize_t)w);
1N/A }
1N/A }
1N/A
1N/A if(local)
1N/A SETLOCAL(f);
1N/A switch(_sfexcept(f,SF_WRITE,w,dc))
1N/A {
1N/A case SF_ECONT :
1N/A goto do_continue;
1N/A case SF_EDONE :
1N/A w = local ? 0 : w;
1N/A SFMTXRETURN(f, (ssize_t)w);
1N/A case SF_EDISC :
1N/A if(!local && !(f->flags&SF_STRING))
1N/A goto do_continue;
1N/A /* else fall thru */
1N/A case SF_ESTACK :
1N/A SFMTXRETURN(f, (ssize_t)(-1));
1N/A }
1N/A
1N/A do_continue:
1N/A for(dc = f->disc; dc; dc = dc->disc)
1N/A if(dc == disc)
1N/A break;
1N/A disc = dc;
1N/A }
1N/A}