(2006-08-06) rescue-bootcd

extra/syslinux-3.09/com32/lib/sys/open.c

@@ -0,0 +1,90 @@
+#ident "$Id: open.c,v 1.4 2004/11/23 23:43:02 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2003-2004 H. Peter Anvin - All Rights Reserved
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *   
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *   
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <errno.h>
+#include <com32.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include "file.h"
+
+/*
+ * open.c
+ *
+ * Open an ordinary file
+ */
+
+extern ssize_t __file_read(struct file_info *, void *, size_t);
+extern int __file_close(struct file_info *);
+
+static const struct input_dev file_dev = {
+  .dev_magic = __DEV_MAGIC,
+  .flags     = __DEV_FILE | __DEV_INPUT,
+  .fileflags = O_RDONLY,
+  .read      = __file_read,
+  .close     = __file_close,
+};
+
+int open(const char *pathname, int flags, ...)
+{
+  com32sys_t regs;
+  int fd;
+  struct file_info *fp;
+
+  fd = opendev(&file_dev, NULL, flags);
+
+  if ( fd < 0 )
+    return -1;
+  
+  fp = &__file_info[fd];
+
+  strlcpy(__com32.cs_bounce, pathname, __com32.cs_bounce_size);
+
+  regs.eax.w[0] = 0x0006;
+  regs.esi.w[0] = OFFS(__com32.cs_bounce);
+  regs.es = SEG(__com32.cs_bounce);
+
+  __com32.cs_intcall(0x22, &regs, &regs);
+  
+  if ( (regs.eflags.l & EFLAGS_CF) || regs.esi.w[0] == 0 ) {
+    errno = ENOENT;
+    return -1;
+  }
+
+  {
+    uint16_t blklg2;
+    asm("bsrw %1,%0" : "=r" (blklg2) : "rm" (regs.ecx.w[0]));
+    fp->i.blocklg2 = blklg2;
+  }
+  fp->i.length    = regs.eax.l;
+  fp->i.filedes   = regs.esi.w[0];
+  fp->i.offset    = 0;
+  fp->i.nbytes    = 0;
+
+  return fd;
+}