usr/src/lib/libast/common/port/astcopy.c

   1 /***********************************************************************
   2 *                                                                      *
   3 *               This software is part of the ast package               *
   4 *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
   5 *                      and is licensed under the                       *
   6 *                  Common Public License, Version 1.0                  *
   7 *                    by AT&T Intellectual Property                     *
   8 *                                                                      *
   9 *                A copy of the License is available at                 *
  10 *            http://www.opensource.org/licenses/cpl1.0.txt             *
  11 *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
  12 *                                                                      *
  13 *              Information and Software Systems Research               *
  14 *                            AT&T Research                             *
  15 *                           Florham Park NJ                            *
  16 *                                                                      *
  17 *                 Glenn Fowler <gsf@research.att.com>                  *
  18 *                  David Korn <dgk@research.att.com>                   *
  19 *                   Phong Vo <kpv@research.att.com>                    *
  20 *                                                                      *
  21 ***********************************************************************/
  22 #pragma prototyped
  23 /*
  24  * Glenn Fowler
  25  * AT&T Bell Laboratories
  26  *
  27  * copy from rfd to wfd (with conditional mmap hacks)
  28  */
  29
  30 #include <ast.h>
  31 #include <ast_mmap.h>
  32
  33 #if _mmap_worthy > 1
  34
  35 #include <ls.h>
  36
  37 #define MAPSIZE         (1024*256)
  38
  39 #endif
  40
  41 #undef  BUFSIZ
  42 #define BUFSIZ          4096
  43
  44 /*
  45  * copy n bytes from rfd to wfd
  46  * actual byte count returned
  47  * if n<=0 then ``good'' size is used
  48  */
  49
  50 off_t
  51 astcopy(int rfd, int wfd, off_t n)
  52 {
  53         register off_t  c;
  54 #ifdef MAPSIZE
  55         off_t           pos;
  56         off_t           mapsize;
  57         char*           mapbuf;
  58         struct stat     st;
  59 #endif
  60
  61         static int      bufsiz;
  62         static char*    buf;
  63
  64         if (n <= 0 || n >= BUFSIZ * 2)
  65         {
  66 #if MAPSIZE
  67                 if (!fstat(rfd, &st) && S_ISREG(st.st_mode) && (pos = lseek(rfd, (off_t)0, 1)) != ((off_t)-1))
  68                 {
  69                         if (pos >= st.st_size) return(0);
  70                         mapsize = st.st_size - pos;
  71                         if (mapsize > MAPSIZE) mapsize = (mapsize > n && n > 0) ? n : MAPSIZE;
  72                         if (mapsize >= BUFSIZ * 2 && (mapbuf = (char*)mmap(NiL, mapsize, PROT_READ, MAP_SHARED, rfd, pos)) != ((caddr_t)-1))
  73                         {
  74                                 if (write(wfd, mapbuf, mapsize) != mapsize || lseek(rfd, mapsize, 1) == ((off_t)-1)) return(-1);
  75                                 munmap((caddr_t)mapbuf, mapsize);
  76                                 return(mapsize);
  77                         }
  78                 }
  79 #endif
  80                 if (n <= 0) n = BUFSIZ;
  81         }
  82         if (n > bufsiz)
  83         {
  84                 if (buf) free(buf);
  85                 bufsiz = roundof(n, BUFSIZ);
  86                 if (!(buf = newof(0, char, bufsiz, 0))) return(-1);
  87         }
  88         if ((c = read(rfd, buf, (size_t)n)) > 0 && write(wfd, buf, (size_t)c) != c) c = -1;
  89         return(c);
  90 }