cde/programs/dtksh/ksh93/src/lib/libast/sfio/sfsetbuf.c

   1 /*
   2  * CDE - Common Desktop Environment
   3  *
   4  * Copyright (c) 1993-2012, The Open Group. All rights reserved.
   5  *
   6  * These libraries and programs are free software; you can
   7  * redistribute them and/or modify them under the terms of the GNU
   8  * Lesser General Public License as published by the Free Software
   9  * Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * These libraries and programs are distributed in the hope that
  13  * they will be useful, but WITHOUT ANY WARRANTY; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with these librararies and programs; if not, write
  20  * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
  21  * Floor, Boston, MA 02110-1301 USA
  22  */
  23 /* $XConsortium: sfsetbuf.c /main/3 1995/11/01 18:35:58 rswiston $ */
  24 /***************************************************************
  25 *                                                              *
  26 *                      AT&T - PROPRIETARY                      *
  27 *                                                              *
  28 *         THIS IS PROPRIETARY SOURCE CODE LICENSED BY          *
  29 *                          AT&T CORP.                          *
  30 *                                                              *
  31 *                Copyright (c) 1995 AT&T Corp.                 *
  32 *                     All Rights Reserved                      *
  33 *                                                              *
  34 *           This software is licensed by AT&T Corp.            *
  35 *       under the terms and conditions of the license in       *
  36 *       http://www.research.att.com/orgs/ssr/book/reuse        *
  37 *                                                              *
  38 *               This software was created by the               *
  39 *           Software Engineering Research Department           *
  40 *                    AT&T Bell Laboratories                    *
  41 *                                                              *
  42 *               For further information contact                *
  43 *                     gsf@research.att.com                     *
  44 *                                                              *
  45 ***************************************************************/
  46 #include        "sfhdr.h"
  47
  48 /*      Set a (new) buffer for a stream.
  49 **      If size < 0, it is assigned a suitable value depending on the
  50 **      kind of stream. The actual buffer size allocated is dependent
  51 **      on how much memory is available.
  52 **
  53 **      Written by Kiem-Phong Vo (06/27/90)
  54 */
  55
  56 #if __STD_C
  57 Void_t* sfsetbuf(reg Sfio_t* f, reg Void_t* buf, reg int size)
  58 #else
  59 Void_t* sfsetbuf(f,buf,size)
  60 reg Sfio_t*     f;      /* stream to be buffered */
  61 reg Void_t*     buf;    /* new buffer */
  62 reg int         size;   /* buffer size, -1 for default size */
  63 #endif
  64 {
  65         reg int         sf_malloc;
  66         struct stat     st;
  67         reg uchar*      obuf;
  68         reg Sfdisc_t*   disc;
  69         reg int         osize, oflags, blksize;
  70         reg int         justopen, init, okmmap, local;
  71
  72         GETLOCAL(f,local);
  73
  74         if(size == 0 && buf)
  75         {       /* special case to get buffer info */
  76                 _Sfi = (f->flags&SF_MMAP) ? (f->endb-f->data) : f->size;
  77                 return (Void_t*)f->data;
  78         }
  79
  80         /* cleanup actions already done, don't allow write buffering any more */
  81         if(_Sfexiting && !(f->flags&SF_STRING) && (f->mode&SF_WRITE))
  82                 return NIL(Void_t*);
  83
  84         if((init = f->mode&SF_INIT) )
  85         {       if(!f->pool && _sfsetpool(f) < 0)
  86                         return NIL(Void_t*);
  87         }
  88         else if((f->mode&SF_RDWR) != SFMODE(f,local) && _sfmode(f,0,local) < 0)
  89                 return NIL(Void_t*);
  90
  91         justopen = f->mode&SF_OPEN;
  92         f->mode &= ~SF_OPEN;
  93         if(init)
  94                 f->mode = (f->mode&SF_RDWR)|SF_LOCK;
  95         else
  96         {       int     rv;
  97
  98                 /* make sure there is no hidden read data */
  99                 if((f->flags&(SF_PROCESS|SF_READ)) == (SF_PROCESS|SF_READ) &&
 100                    (f->mode&SF_WRITE) && _sfmode(f,SF_READ,local) < 0)
 101                         return NIL(Void_t*);
 102
 103                 /* synchronize first */
 104                 SFLOCK(f,local); rv = SFSYNC(f); SFOPEN(f,local);
 105                 if(rv < 0)
 106                         return NIL(Void_t*);
 107
 108                 /* turn off the SF_SYNCED bit because buffer is changing */
 109                 f->mode &= ~SF_SYNCED;
 110         }
 111
 112         SFLOCK(f,local);
 113
 114         blksize = 0;
 115         oflags = f->flags;
 116
 117         /* see if memory mapping is possible (see sfwrite for SF_BOTH) */
 118         okmmap = (buf || (f->flags&SF_STRING) || (f->flags&SF_RDWR) == SF_RDWR) ? 0 : 1;
 119
 120         /* save old buffer info */
 121 #ifdef MAP_TYPE
 122         if(f->flags&SF_MMAP)
 123         {       if(f->data)
 124                 {       (void)munmap((caddr_t)f->data,f->endb-f->data);
 125                         f->data = NIL(uchar*);
 126                 }
 127         } else
 128 #endif
 129         if(f->data == f->tiny)
 130         {       f->data = NIL(uchar*);
 131                 f->size = 0;
 132         }
 133         obuf  = f->data;
 134         osize = f->size;
 135
 136         f->flags &= ~(SF_MMAP|SF_MALLOC);
 137
 138         /* pure read/string streams must have a valid string */
 139         if((f->flags&(SF_RDWR|SF_STRING)) == SF_RDSTR && (size < 0 || !buf))
 140                 size = 0;
 141
 142         /* set disc to the first discipline with a seekf */
 143         for(disc = f->disc; disc; disc = disc->disc)
 144                 if(disc->seekf)
 145                         break;
 146
 147         if((init || local) && !(f->flags&SF_STRING))
 148         {       /* ASSERT(f->file >= 0) */
 149                 st.st_mode = 0;
 150
 151                 /* if has discipline, set size by discipline if possible */
 152                 if(disc)
 153                 {       if((f->here = SFSK(f,0L,1,disc)) < 0)
 154                                 goto unseekable;
 155                         else
 156                         {       f->extent = SFSK(f,0L,2,disc);
 157                                 (void)SFSK(f,f->here,0,disc);
 158                                 goto setbuf;
 159                         }
 160                 }
 161
 162                 /* get file descriptor status */
 163                 if(fstat(f->file,&st) < 0)
 164                         goto unseekable;
 165
 166 #if _stat_blksize       /* preferred io block size */
 167                 if((blksize = (int)st.st_blksize) > 0)
 168                         while((blksize + (int)st.st_blksize) <= SF_PAGE)
 169                                 blksize += (int)st.st_blksize;
 170 #endif
 171                 if(S_ISREG(st.st_mode) || S_ISDIR(st.st_mode))
 172                         f->here = justopen ? 0L : SFSK(f,0L,1,f->disc);
 173                 else    f->here = -1;
 174                 if(f->here >= 0)
 175                 {       /* normal file, set file extent */
 176                         f->extent = (long)st.st_size;
 177
 178                         /* don't MMAP directories */
 179                         if(S_ISDIR(st.st_mode) )
 180                                 okmmap = 0;
 181
 182                         /* seekable std-devices are share-public by default */
 183                         if(f == sfstdin || f == sfstdout || f == sfstderr)
 184                                 f->flags |= SF_SHARE|SF_PUBLIC;
 185                 }
 186                 else
 187                 {
 188                 unseekable:
 189                         f->extent = -1L;
 190                         f->here = 0L;
 191
 192                         if(init)
 193                         {       /* pipe std-devices are automatically shared */
 194                                 if(S_ISFIFO(st.st_mode) )
 195                                 {       if(f == sfstdin || f == sfstdout || f == sfstderr)                                              f->flags |= SF_SHARE;
 196                                 }
 197                                 else if(S_ISCHR(st.st_mode) )
 198                                 {       /* set line mode for terminals */
 199                                         if(!(f->flags&SF_LINE) && isatty(f->file))
 200                                                 f->flags |= SF_LINE;
 201
 202                                         /* special case /dev/null for efficiency */
 203                                         else
 204                                         {       reg int dev, ino;
 205                                                 dev = (int)st.st_dev;
 206                                                 ino = (int)st.st_ino;
 207                                                 if(stat(DEVNULL,&st) >= 0 &&
 208                                                    dev == st.st_dev && ino == st.st_ino)
 209                                                 {       SFSETNULL(f);
 210                                                         blksize = 1024;
 211                                                 }
 212                                         }
 213                                 }
 214
 215                                 /* initialize save input buffer for r+w streams */
 216                                 if(!(f->flags&SF_PROCESS) && (f->flags&SF_BOTH) )
 217                                         (void)_sfpopen(f,-1,-1);
 218                         }
 219                 }
 220
 221                 /* set page size, this is also the desired default buffer size */
 222 #if _lib_getpagesize
 223                 if(_Sfpage <= 0)
 224                         _Sfpage = (int)getpagesize();
 225 #endif
 226                 if(_Sfpage <= 0)
 227                         _Sfpage = SF_PAGE;
 228         }
 229
 230 #ifdef MAP_TYPE
 231         if(okmmap && size && (f->mode&SF_READ) && f->extent >= 0 )
 232         {       /* see if we can try memory mapping */
 233                 if(!disc)
 234                         for(disc = f->disc; disc; disc = disc->disc)
 235                                 if(disc->readf)
 236                                         break;
 237                 if(!disc)
 238                 {       f->flags |= SF_MMAP;
 239                         if(size < 0)
 240                         {       size = (blksize > 0 ? blksize : _Sfpage) * SF_NMAP;
 241                                 size = ((size+_Sfpage-1)/_Sfpage)*_Sfpage;
 242                         }
 243                 }
 244         }
 245 #endif
 246
 247         /* get buffer space */
 248 setbuf:
 249         if(size < 0)
 250         {       /* define a default size suitable for block transfer */
 251                 if(init && osize > 0)
 252                         size = osize;
 253                 else if(f == sfstderr && (f->mode&SF_WRITE))
 254                         size = 0;
 255                 else if((f->flags&SF_STRING) || f->extent < 0)
 256                         size = SF_GRAIN;
 257                 else if(blksize > 0)
 258                         size = blksize;
 259                 else if((f->flags&(SF_READ|SF_BOTH)) == SF_READ &&
 260                         f->extent > 0 && f->extent < _Sfpage )
 261                         size = (((int)f->extent + SF_GRAIN-1)/SF_GRAIN)*SF_GRAIN;
 262                 else    size = _Sfpage;
 263
 264                 buf = NIL(Void_t*);
 265         }
 266
 267         sf_malloc = 0;
 268         if(size > 0 && !buf && !(f->flags&SF_MMAP))
 269         {       /* try to allocate a buffer */
 270                 if(obuf && size == osize)
 271                 {       buf = (Void_t*)obuf;
 272                         obuf = NIL(uchar*);
 273                         sf_malloc = (oflags&SF_MALLOC);
 274                 }
 275                 if(!buf)
 276                 {       /* do allocation */
 277                         while(!(buf = (Void_t*) malloc(size)) && size > 0)
 278                                 size /= 2;
 279                         if(size > 0)
 280                                 sf_malloc = SF_MALLOC;
 281                 }
 282         }
 283
 284         if(size == 0 && !(f->flags&(SF_MMAP|SF_STRING)) && (f->mode&SF_READ))
 285         {       /* use the internal buffer */
 286                 size = sizeof(f->tiny);
 287                 buf = (Void_t*)f->tiny;
 288         }
 289
 290         /* set up new buffer */
 291         f->size = size;
 292         f->next = f->data = f->endr = f->endw = (uchar*)buf;
 293         f->endb = (f->mode&SF_READ) ? f->data : f->data+size;
 294         if(f->flags&SF_STRING)
 295         {       /* these fields are used to test actual size - see sfseek() */
 296                 f->extent = (!sf_malloc && (f->flags&(SF_BOTH|SF_READ))) ? size : 0;
 297                 f->here = 0L;
 298
 299                 /* read+string stream should have all data available */
 300                 if((f->mode&SF_READ) && !sf_malloc)
 301                         f->endb = f->data+size;
 302         }
 303
 304         f->flags = (f->flags & ~SF_MALLOC)|sf_malloc;
 305
 306         if(obuf && obuf != f->data && osize > 0 && (oflags&SF_MALLOC))
 307         {       free((Void_t*)obuf);
 308                 obuf = NIL(uchar*);
 309         }
 310
 311         _Sfi = obuf ? osize : 0;
 312
 313         SFOPEN(f,local);
 314
 315         return (Void_t*)obuf;
 316 }