14887Schin /***********************************************************************
24887Schin * *
34887Schin * This software is part of the ast package *
4*12068SRoger.Faulkner@Oracle.COM * Copyright (c) 1985-2010 AT&T Intellectual Property *
54887Schin * and is licensed under the *
64887Schin * Common Public License, Version 1.0 *
78462SApril.Chin@Sun.COM * by AT&T Intellectual Property *
84887Schin * *
94887Schin * A copy of the License is available at *
104887Schin * http://www.opensource.org/licenses/cpl1.0.txt *
114887Schin * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
124887Schin * *
134887Schin * Information and Software Systems Research *
144887Schin * AT&T Research *
154887Schin * Florham Park NJ *
164887Schin * *
174887Schin * Glenn Fowler <gsf@research.att.com> *
184887Schin * David Korn <dgk@research.att.com> *
194887Schin * Phong Vo <kpv@research.att.com> *
204887Schin * *
214887Schin ***********************************************************************/
224887Schin #include "sfhdr.h"
234887Schin
244887Schin /* Write with discipline.
254887Schin **
264887Schin ** Written by Kiem-Phong Vo.
274887Schin */
284887Schin
294887Schin /* hole preserving writes */
304887Schin #if __STD_C
sfoutput(Sfio_t * f,char * buf,size_t n)318462SApril.Chin@Sun.COM static ssize_t sfoutput(Sfio_t* f, char* buf, size_t n)
324887Schin #else
334887Schin static ssize_t sfoutput(f,buf,n)
344887Schin Sfio_t* f;
358462SApril.Chin@Sun.COM char* buf;
368462SApril.Chin@Sun.COM size_t n;
374887Schin #endif
384887Schin { reg char *sp, *wbuf, *endbuf;
394887Schin reg ssize_t s, w, wr;
404887Schin
414887Schin s = w = 0;
424887Schin wbuf = buf;
434887Schin endbuf = buf+n;
444887Schin while(n > 0)
454887Schin { if((ssize_t)n < _Sfpage) /* no hole possible */
464887Schin { buf += n;
474887Schin s = n = 0;
484887Schin }
494887Schin else while((ssize_t)n >= _Sfpage)
504887Schin { /* see if a hole of 0's starts here */
514887Schin sp = buf+1;
524887Schin if(buf[0] == 0 && buf[_Sfpage-1] == 0)
534887Schin { /* check byte at a time until int-aligned */
544887Schin while(((ulong)sp)%sizeof(int))
554887Schin { if(*sp != 0)
564887Schin goto chk_hole;
574887Schin sp += 1;
584887Schin }
594887Schin
604887Schin /* check using int to speed up */
614887Schin while(sp < endbuf)
624887Schin { if(*((int*)sp) != 0)
634887Schin goto chk_hole;
644887Schin sp += sizeof(int);
654887Schin }
664887Schin
674887Schin /* check the remaining bytes */
684887Schin if(sp > endbuf)
694887Schin { sp -= sizeof(int);
704887Schin while(sp < endbuf)
714887Schin { if(*sp != 0)
724887Schin goto chk_hole;
734887Schin sp += 1;
744887Schin }
754887Schin }
764887Schin }
774887Schin
784887Schin chk_hole:
794887Schin if((s = sp-buf) >= _Sfpage) /* found a hole */
804887Schin break;
814887Schin
824887Schin /* skip a dirty page */
834887Schin n -= _Sfpage;
844887Schin buf += _Sfpage;
854887Schin }
864887Schin
874887Schin /* write out current dirty pages */
884887Schin if(buf > wbuf)
894887Schin { if((ssize_t)n < _Sfpage)
904887Schin { buf = endbuf;
914887Schin n = s = 0;
924887Schin }
934887Schin if((wr = syswritef(f->file,wbuf,buf-wbuf)) > 0)
944887Schin { w += wr;
954887Schin f->bits &= ~SF_HOLE;
964887Schin }
974887Schin if(wr != (buf-wbuf))
984887Schin break;
994887Schin wbuf = buf;
1004887Schin }
1014887Schin
1024887Schin /* seek to a rounded boundary within the hole */
1034887Schin if(s >= _Sfpage)
1044887Schin { s = (s/_Sfpage)*_Sfpage;
1054887Schin if(SFSK(f,(Sfoff_t)s,SEEK_CUR,NIL(Sfdisc_t*)) < 0)
1064887Schin break;
1074887Schin w += s;
1084887Schin n -= s;
1094887Schin wbuf = (buf += s);
1104887Schin f->bits |= SF_HOLE;
1114887Schin
1124887Schin if(n > 0)
1134887Schin { /* next page must be dirty */
1144887Schin s = (ssize_t)n <= _Sfpage ? 1 : _Sfpage;
1154887Schin buf += s;
1164887Schin n -= s;
1174887Schin }
1184887Schin }
1194887Schin }
1204887Schin
1214887Schin return w > 0 ? w : -1;
1224887Schin }
1234887Schin
1244887Schin #if __STD_C
sfwr(Sfio_t * f,const Void_t * buf,size_t n,Sfdisc_t * disc)1258462SApril.Chin@Sun.COM ssize_t sfwr(Sfio_t* f, const Void_t* buf, size_t n, Sfdisc_t* disc)
1264887Schin #else
1274887Schin ssize_t sfwr(f,buf,n,disc)
1288462SApril.Chin@Sun.COM Sfio_t* f;
1298462SApril.Chin@Sun.COM Void_t* buf;
1308462SApril.Chin@Sun.COM size_t n;
1318462SApril.Chin@Sun.COM Sfdisc_t* disc;
1324887Schin #endif
1334887Schin {
1344887Schin reg ssize_t w;
1354887Schin reg Sfdisc_t* dc;
1364887Schin reg int local, oerrno;
1378462SApril.Chin@Sun.COM SFMTXDECL(f);
1384887Schin
1398462SApril.Chin@Sun.COM SFMTXENTER(f,(ssize_t)(-1));
1404887Schin
1414887Schin GETLOCAL(f,local);
1424887Schin if(!local && !(f->bits&SF_DCDOWN)) /* an external user's call */
1434887Schin { if(f->mode != SF_WRITE && _sfmode(f,SF_WRITE,0) < 0 )
1444887Schin SFMTXRETURN(f, (ssize_t)(-1));
1454887Schin if(f->next > f->data && SFSYNC(f) < 0 )
1464887Schin SFMTXRETURN(f, (ssize_t)(-1));
1474887Schin }
1484887Schin
1494887Schin for(;;)
1504887Schin { /* stream locked by sfsetfd() */
1514887Schin if(!(f->flags&SF_STRING) && f->file < 0)
1524887Schin SFMTXRETURN(f,(ssize_t)0);
1534887Schin
1544887Schin /* clear current error states */
1554887Schin f->flags &= ~(SF_EOF|SF_ERROR);
1564887Schin
1574887Schin dc = disc;
1584887Schin if(f->flags&SF_STRING) /* total required buffer */
1594887Schin w = n + (f->next - f->data);
1604887Schin else
1614887Schin { /* warn that a write is about to happen */
1624887Schin SFDISC(f,dc,writef);
1634887Schin if(dc && dc->exceptf && (f->flags&SF_IOCHECK) )
1644887Schin { reg int rv;
1654887Schin if(local)
1664887Schin SETLOCAL(f);
1674887Schin if((rv = _sfexcept(f,SF_WRITE,n,dc)) > 0)
1684887Schin n = rv;
1694887Schin else if(rv < 0)
1704887Schin { f->flags |= SF_ERROR;
1714887Schin SFMTXRETURN(f, rv);
1724887Schin }
1734887Schin }
1744887Schin
1754887Schin if(f->extent >= 0)
1764887Schin { /* make sure we are at the right place to write */
1774887Schin if(f->flags&SF_APPENDWR)
1784887Schin { if(f->here != f->extent || (f->flags&SF_SHARE))
1794887Schin { f->here = SFSK(f,(Sfoff_t)0,SEEK_END,dc);
1804887Schin f->extent = f->here;
1814887Schin }
1824887Schin }
1834887Schin else if((f->flags&SF_SHARE) && !(f->flags&SF_PUBLIC))
1844887Schin f->here = SFSK(f,f->here,SEEK_SET,dc);
1854887Schin }
1864887Schin
1874887Schin oerrno = errno;
1884887Schin errno = 0;
1894887Schin
1904887Schin if(dc && dc->writef)
1914887Schin { SFDCWR(f,buf,n,dc,w);
1924887Schin }
1934887Schin else if(SFISNULL(f))
1944887Schin w = n;
1954887Schin else if(f->flags&SF_WHOLE)
1964887Schin goto do_write;
1974887Schin else if((ssize_t)n >= _Sfpage &&
1984887Schin !(f->flags&(SF_SHARE|SF_APPENDWR)) &&
1994887Schin f->here == f->extent && (f->here%_Sfpage) == 0)
2004887Schin { if((w = sfoutput(f,(char*)buf,n)) <= 0)
2014887Schin goto do_write;
2024887Schin }
2034887Schin else
2044887Schin {
2054887Schin do_write:
2064887Schin if((w = syswritef(f->file,buf,n)) > 0)
2074887Schin f->bits &= ~SF_HOLE;
2084887Schin }
2094887Schin
2104887Schin if(errno == 0)
2114887Schin errno = oerrno;
2124887Schin
2134887Schin if(w > 0)
2144887Schin { if(!(f->bits&SF_DCDOWN) )
2154887Schin { if((f->flags&(SF_APPENDWR|SF_PUBLIC)) && f->extent >= 0 )
2164887Schin f->here = SFSK(f,(Sfoff_t)0,SEEK_CUR,dc);
2174887Schin else f->here += w;
2184887Schin if(f->extent >= 0 && f->here > f->extent)
2194887Schin f->extent = f->here;
2204887Schin }
2214887Schin
2224887Schin SFMTXRETURN(f, (ssize_t)w);
2234887Schin }
2244887Schin }
2254887Schin
2264887Schin if(local)
2274887Schin SETLOCAL(f);
2284887Schin switch(_sfexcept(f,SF_WRITE,w,dc))
2294887Schin {
2304887Schin case SF_ECONT :
2314887Schin goto do_continue;
2324887Schin case SF_EDONE :
2334887Schin w = local ? 0 : w;
2344887Schin SFMTXRETURN(f, (ssize_t)w);
2354887Schin case SF_EDISC :
2364887Schin if(!local && !(f->flags&SF_STRING))
2374887Schin goto do_continue;
2384887Schin /* else fall thru */
2394887Schin case SF_ESTACK :
2404887Schin SFMTXRETURN(f, (ssize_t)(-1));
2414887Schin }
2424887Schin
2434887Schin do_continue:
2444887Schin for(dc = f->disc; dc; dc = dc->disc)
2454887Schin if(dc == disc)
2464887Schin break;
2474887Schin disc = dc;
2484887Schin }
2494887Schin }
250