usr.sbin/sup/source/ffilecopy.c

   1 /*      $NetBSD: ffilecopy.c,v 1.10 2009/10/17 22:26:13 christos Exp $  */
   2
   3 /*
   4  * Copyright (c) 1991 Carnegie Mellon University
   5  * All Rights Reserved.
   6  *
   7  * Permission to use, copy, modify and distribute this software and its
   8  * documentation is hereby granted, provided that both the copyright
   9  * notice and this permission notice appear in all copies of the
  10  * software, derivative works or modified versions, and any portions
  11  * thereof, and that both notices appear in supporting documentation.
  12  *
  13  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  14  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  15  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  16  *
  17  * Carnegie Mellon requests users of this software to return to
  18  *
  19  *  Software Distribution Coordinator   or   Software.Distribution@CS.CMU.EDU
  20  *  School of Computer Science
  21  *  Carnegie Mellon University
  22  *  Pittsburgh PA 15213-3890
  23  *
  24  * any improvements or extensions that they make and grant Carnegie the rights
  25  * to redistribute these changes.
  26  */
  27
  28 #include <stdio.h>
  29 #include "supcdefs.h"
  30 #include "supextern.h"
  31
  32 /*
  33  *      Define two macros for fast file copying
  34  *
  35  *      FBUF_HACK: this will copy data directly between the
  36  *      underlying OSs FILE buffers
  37  *
  38  *      FFLAG_HACK: this will set necessary OS FILE flags
  39  *      after we've hacked the buffers up
  40  */
  41
  42 #if defined(__SEOF)
  43
  44 # define FBUF_HACK(here,there) \
  45         do { \
  46                 if ((here)->_r > 0) { \
  47                         i = write(therefile, (here)->_p, (size_t)(here)->_r); \
  48                         if (i != (here)->_r) \
  49                                 return EOF; \
  50                         (here)->_p = (here)->_bf._base; \
  51                         (here)->_r = 0; \
  52                 } \
  53         } while (/*CONSTCOND*/0)
  54 # define FFLAG_HACK(file) (file)->_flags |= __SEOF
  55
  56 #elif defined(_IOEOF)
  57
  58 # define FBUF_HACK(here, there) \
  59         do { \
  60                 if ((here)->_cnt > 0) { \
  61                         i = write(therefile, (here)->_ptr, (here)->_cnt ); \
  62                         if (i != (here)->_cnt) \
  63                                 return EOF; \
  64                         (here)->_ptr = (here)->_base; \
  65                         (here)->_cnt = 0; \
  66                 } \
  67         } while (/*CONSTCOND*/0)
  68 # define FFLAG_HACK(file) (file)->_flag |= _IOEOF;
  69
  70 #else
  71
  72 # define FBUF_HACK(here, there) /* Nada */
  73 # define FFLAG_HACK(here) (void)fseeko(here, (off_t)0, SEEK_END);
  74
  75 #endif
  76
  77 /*  ffilecopy  --  very fast buffered file copy
  78  *
  79  *  Usage:  i = ffilecopy (here,there)
  80  *      int i;
  81  *      FILE *here, *there;
  82  *
  83  *  Ffilecopy is a very fast routine to copy the rest of a buffered
  84  *  input file to a buffered output file.  Here and there are open
  85  *  buffers for reading and writing (respectively); ffilecopy
  86  *  performs a file-copy faster than you should expect to do it
  87  *  yourself.  Ffilecopy returns 0 if everything was OK; EOF if
  88  *  there was any error.  Normally, the input file will be left in
  89  *  EOF state (feof(here) will return TRUE), and the output file will be
  90  *  flushed (i.e. all data on the file rather in the core buffer).
  91  *  It is not necessary to flush the output file before ffilecopy.
  92  *
  93  *  HISTORY
  94  * 20-Nov-79  Steven Shafer (sas) at Carnegie-Mellon University
  95  *      Created for VAX.
  96  *
  97  */
  98
  99 ssize_t
 100 ffilecopy(FILE * here, FILE * there)
 101 {
 102         int i, herefile, therefile;
 103
 104         herefile = fileno(here);
 105         therefile = fileno(there);
 106
 107         if (fflush(there) == EOF)       /* flush pending output */
 108                 return EOF;
 109
 110         /* if we know any buffer tricks, do them now */
 111         FBUF_HACK(here,there);
 112
 113         /* copy the rest of the file directly (avoiding FILE buffers) */
 114         i = filecopy(herefile, therefile);      /* fast file copy */
 115         if (i < 0)
 116                 return EOF;
 117
 118         /* ensure we are at the end of the file */
 119         FFLAG_HACK(here);
 120         return 0;
 121 }