From 20e894ed3460ba09c0086ae7a363129b938b26e6 Mon Sep 17 00:00:00 2001
From: Miles Bader <miles@gnu.org>
Date: Sun, 5 Nov 1995 04:27:35 +0000
Subject: Initial revision

---
 libdiskfs/filedev.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 107 insertions(+)
 create mode 100644 libdiskfs/filedev.c

diff --git a/libdiskfs/filedev.c b/libdiskfs/filedev.c
new file mode 100644
index 00000000..5a3e752d
--- /dev/null
+++ b/libdiskfs/filedev.c
@@ -0,0 +1,107 @@
+/* Get the mach device underlying a file
+
+   Copyright (C) 1995 Free Software Foundation, Inc.
+
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2, or (at
+   your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
+
+#include <errno.h>
+#include <sys/fcntl.h>
+
+#include <device/device.h>
+
+#include "priv.h"
+
+typedef int run_elem_t;
+
+/* Returns the name and a send right for the mach device on which the file
+   NAME is stored, and returns it in DEV_NAME (which is malloced) and PORT.
+   Other values returned are START, the first valid offset, SIZE, the the
+   number of blocks after START, and BLOCK_SIZE, the units in which the
+   device is addressed.
+
+   The device is opened for reading, and if the diskfs global variable
+   DISKFS_READONLY is false, writing.  */
+error_t
+diskfs_get_file_device (char *name,
+			char **dev_name, mach_port_t *port,
+			off_t *start, off_t *size, size_t *block_size)
+{
+  error_t err;
+  int class, flags;
+  char *misc = 0;
+  off_t *runs = 0;
+  mach_msg_type_number_t misc_len = 0, runs_len = 0;
+  string_t dev_name_buf;
+  file_t node =
+    file_name_lookup (name, diskfs_readonly ? O_RDONLY : O_RDWR, 0);
+
+  if (node == MACH_PORT_NULL)
+    return errno;
+
+  *port = MACH_PORT_NULL;
+
+  err = file_get_storage_info (node, &class, &runs, &runs_len, block_size,
+			       dev_name_buf, port, &misc, &misc_len, &flags);
+  if (err)
+    goto done;
+
+  if (class != STORAGE_DEVICE)
+    {
+      err = ENODEV;
+      goto done;
+    }
+
+  if (dev_name)
+    {
+      *dev_name = malloc (strlen (dev_name_buf) + 1);
+      if (*dev_name)
+	strcpy (*dev_name, dev_name_buf);
+      else
+	err = ENOMEM;
+    }
+
+  if (start || size)
+    if (runs_len > 2)
+      /* We can't handle anything but a contiguous set of blocks.  */
+      err = ENODEV;		/* XXX */
+    else
+      {
+	if (start)
+	  *start = runs[0];
+	if (size)
+	  *size = runs[1];
+      }
+
+  /* Note that we don't deallocate NODE, which should prevent the information
+     returned by file_get_storage_info from changing.  */
+
+ done:
+  if (err)
+    {
+      mach_port_deallocate (mach_task_self (), node);
+      if (*port)
+	mach_port_deallocate (mach_task_self (), *port);
+    }
+
+  if (misc_len > 0)
+    vm_deallocate (mach_task_self (), (vm_address_t)misc, misc_len);
+  if (runs_len > 0)
+    vm_deallocate (mach_task_self (),
+		   (vm_address_t)runs, runs_len * sizeof (*runs));
+  
+  return err;
+}
-- 
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