com32/lib/sys/open.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2003-2006 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   Permission is hereby granted, free of charge, to any person
   6  *   obtaining a copy of this software and associated documentation
   7  *   files (the "Software"), to deal in the Software without
   8  *   restriction, including without limitation the rights to use,
   9  *   copy, modify, merge, publish, distribute, sublicense, and/or
  10  *   sell copies of the Software, and to permit persons to whom
  11  *   the Software is furnished to do so, subject to the following
  12  *   conditions:
  13  *
  14  *   The above copyright notice and this permission notice shall
  15  *   be included in all copies or substantial portions of the Software.
  16  *
  17  *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  18  *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
  19  *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  20  *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
  21  *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
  22  *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24  *   OTHER DEALINGS IN THE SOFTWARE.
  25  *
  26  * ----------------------------------------------------------------------- */
  27
  28 #include <errno.h>
  29 #include <com32.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32 #include <fcntl.h>
  33 #include "file.h"
  34
  35 /*
  36  * open.c
  37  *
  38  * Open an ordinary file
  39  */
  40
  41 extern ssize_t __file_read(struct file_info *, void *, size_t);
  42 extern int __file_close(struct file_info *);
  43
  44 static const struct input_dev file_dev = {
  45   .dev_magic = __DEV_MAGIC,
  46   .flags     = __DEV_FILE | __DEV_INPUT,
  47   .fileflags = O_RDONLY,
  48   .read      = __file_read,
  49   .close     = __file_close,
  50   .open      = NULL,
  51 };
  52
  53 int open(const char *pathname, int flags, ...)
  54 {
  55   com32sys_t regs;
  56   int fd;
  57   struct file_info *fp;
  58
  59   fd = opendev(&file_dev, NULL, flags);
  60
  61   if ( fd < 0 )
  62     return -1;
  63
  64   fp = &__file_info[fd];
  65
  66   strlcpy(__com32.cs_bounce, pathname, __com32.cs_bounce_size);
  67
  68   regs.eax.w[0] = 0x0006;
  69   regs.esi.w[0] = OFFS(__com32.cs_bounce);
  70   regs.es = SEG(__com32.cs_bounce);
  71
  72   __com32.cs_intcall(0x22, &regs, &regs);
  73
  74   if ( (regs.eflags.l & EFLAGS_CF) || regs.esi.w[0] == 0 ) {
  75     errno = ENOENT;
  76     return -1;
  77   }
  78
  79   {
  80     uint16_t blklg2;
  81     asm("bsrw %1,%0" : "=r" (blklg2) : "rm" (regs.ecx.w[0]));
  82     fp->i.blocklg2 = blklg2;
  83   }
  84   fp->i.length    = regs.eax.l;
  85   fp->i.filedes   = regs.esi.w[0];
  86   fp->i.offset    = 0;
  87   fp->i.nbytes    = 0;
  88
  89   return fd;
  90 }