Re: bugfix, hostfs

[Tomas Ebenlendr]

At the end of the mail are new versions of patches. Hope, there are few
(or no) GCS-errors.


> > > > +  if ((signed) device->disk->id != -2) {
> > >
> > > What is -2?
> >
> > Oh, sorry. Just a magic constant. Probably there should be better
> > identification (e.g. magic device->disk->data (e.g. device->disk ==
> > device->disk->data)). This identification is used in hostfs_mount()
> 
> Probably the id is a problem on Open Firmware potentially, since Marco 
> used phandlers for disk ids and phandlers can be anything in theory.
> 
> I bet that I made a mistake in the design of struct grub_disk. I thought 
> it would be easy to find an identifier because the size of an id is 
> 4-byte. But this assumption breaks on Open Firmware. So perhaps we 
> should add one more id for the type of a disk, so that we can write 
> this kind of code:
> 
> (include/grub/disk.h)
> enum grub_disk_class_id
>   {
>     GRUB_DISK_CLASS_IEEE1275_ID,
>     GRUB_DISK_CLASS_PCBIOS_ID,
>     GRUB_DISK_CLASS_HOST_ID,
>   };
> 
> (disk/powerpc/ieee1275/ofdisk.c)
> disk->class_id = GRUB_DISK_CLASS_IEEE1275_ID;
> disk->id = phandler;
> 
> Then you can use this:
> 
> disk->class_id = GRUB_DISK_CLASS_HOST_ID;
> disk->id = 0;
> 
> This requires some changes in the cache manager, but not difficult. What 
> do you think?

Hmm, leaving this change for anybody who understand disks in grub.
Instead of it I use disk->name :-) .

> > > > +  grub_strncpy(pathbuf,path,/*FIXME*/2048 - 1);
> > >
> > > Why do you use pathbuf?  Can't you just use path directly?  If that
> > > is not possible use MAX_PATH_LEN here when it is defined and
> > > dynamic memory allocation otherwise (when there is no limit).
> >
> > I concatenate path of directory and its entries to stat them. I will
> > use the MAX_PATH_LEN. I only forgot that I forgot the name of this
> > constant. (Uh).
> 
> You should not use MAX_PATH_LEN if not defined, otherwise you code won't 
> work well on GNU/Hurd. The right way is to allocate memory dynamically 
> for PATHBUF:

I don't use MAX_PATH_LEN even if defined now: Less #ifdef means less
bugs.


I will commit both following patches if you agree. I tested both on
i386,pc,linux-2.4.

PS.: I'm changing conf/powerpc-ieee1275.rmk and I didn't test
  compilability of my code on ppc. But it should be OS-dependent, but
  not architecture dependent.

##########################################################################
Changelog:
2004-08-08  Tomas Ebenlendr  <address@hidden>

        * kern/dl.c (grub_dl_load_file): Fixed bug: When
        grub_dl_load_core fails, mod shouldn't be derefered.

Index: kern/dl.c
===================================================================
RCS file: /cvsroot/grub/grub2/kern/dl.c,v
retrieving revision 1.7
diff -p -u -r1.7 dl.c
--- kern/dl.c   4 Apr 2004 13:46:01 -0000       1.7
+++ kern/dl.c   12 Aug 2004 21:37:53 -0000
@@ -548,7 +548,8 @@ grub_dl_load_file (const char *filename)
     goto failed;
 
   mod = grub_dl_load_core (core, size);
-  mod->ref_count = 0;
+  if (mod)
+    mod->ref_count = 0;
 
  failed:
   grub_file_close (file);
##########################################################################

Changelog:
2004-08-08  Tomas Ebenlendr  <address@hidden>

        Added support for accessing files via host filesystem to
        grub-emu.

        * conf/i386-pc.rmk (grub_emu_SOURCES): Added util/hostdisk.c
        and fs/hostfs.c
        * fs/hostfs.c: New file. Connects grub fs interface and libc file
        interface.
        * include/grub/fakedisk.h: New file, prototypes for inicialization
        and destruction of fakedisk device.
        * util/fakedisk.c: New file, implements device "host" (i.e., tells
        that device "host" is fake-disk with filesystem hostfs).
        * util/grub-emu.c (main): Added inicialzation and destruction
        of hostfs and fakedisk.


diff -rupN -x CVS grub2_x/conf/i386-pc.rmk grub2_wodiff/conf/i386-pc.rmk
--- grub2_x/conf/i386-pc.rmk    2004-08-08 19:32:20.000000000 +0200
+++ grub2_wodiff/conf/i386-pc.rmk       2004-08-10 14:13:32.000000000 +0200
@@ -69,7 +69,8 @@ grub_emu_SOURCES = kern/main.c kern/devi
         kern/misc.c kern/loader.c kern/rescue.c kern/term.c            \
        disk/i386/pc/partition.c kern/env.c commands/ls.c               \
        commands/terminal.c commands/boot.c commands/cmp.c commands/cat.c       
        \
-       util/i386/pc/biosdisk.c fs/fat.c fs/ext2.c fs/ufs.c fs/minix.c          
        \
+       util/i386/pc/biosdisk.c util/fakedisk.c                         \
+       fs/fat.c fs/ext2.c fs/ufs.c fs/minix.c fs/hostfs.c              \
        normal/cmdline.c normal/command.c normal/main.c normal/menu.c 
normal/arg.c      \
        util/console.c util/grub-emu.c util/misc.c util/i386/pc/getroot.c
 grub_emu_LDFLAGS = -lncurses
diff -rupN -x CVS grub2_x/conf/powerpc-ieee1275.rmk 
grub2_wodiff/conf/powerpc-ieee1275.rmk
--- grub2_x/conf/powerpc-ieee1275.rmk   2004-08-08 19:32:20.000000000 +0200
+++ grub2_wodiff/conf/powerpc-ieee1275.rmk      2004-08-12 23:59:07.000000000 
+0200
@@ -25,7 +25,8 @@ grub_emu_SOURCES = kern/main.c kern/devi
        kern/disk.c kern/dl.c kern/file.c kern/fs.c kern/err.c          \
         kern/misc.c kern/loader.c kern/rescue.c kern/term.c            \
        disk/powerpc/ieee1275/partition.c                                       
\
-       util/i386/pc/biosdisk.c fs/fat.c fs/ext2.c fs/ufs.c fs/minix.c  \
+       util/i386/pc/biosdisk.c util/fakedisk.c                         \
+       fs/fat.c fs/ext2.c fs/ufs.c fs/minix.c fs/hostfs.c              \
        normal/cmdline.c normal/command.c normal/main.c normal/menu.c   \
        normal/arg.c    \
        util/console.c util/grub-emu.c util/misc.c util/i386/pc/getroot.c \
diff -rupN -x CVS grub2_x/fs/hostfs.c grub2_wodiff/fs/hostfs.c
--- grub2_x/fs/hostfs.c 1970-01-01 01:00:00.000000000 +0100
+++ grub2_wodiff/fs/hostfs.c    2004-08-13 00:06:36.000000000 +0200
@@ -0,0 +1,203 @@
+/* hostfs.c - host filesystem for grub-emu */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2004  Free Software Foundation, Inc.
+ *
+ *  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 of the License, 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 <grub/err.h>
+#include <grub/file.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+#include <grub/disk.h>
+#include <grub/dl.h>
+#include <grub/types.h>
+#include <grub/fakedisk.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <dirent.h>
+
+#ifndef GRUB_UTIL
+# error Cannot live without underlying OS.
+#endif
+
+
+/* FIXME grub consider the fs in utf-8 => use only ascii (0-127) chars.  */
+
+static grub_err_t
+host_mount (grub_device_t device)
+{
+  if (! GRUB_IS_HOST_FAKEDISK(device->disk))
+    return grub_error (GRUB_ERR_BAD_FS, "not a host filesystem");
+  return 0;
+}
+
+/* Maybe not a exact mapping, but at least sufficient.  */
+static grub_err_t
+errno2err (void)
+{
+  grub_err_t r;
+  switch (errno)
+    {
+      case EMFILE:
+      case ENFILE:
+      case ENOMEM: r = GRUB_ERR_OUT_OF_MEMORY; break;
+      case ENOTDIR:
+      case ENOENT: r = GRUB_ERR_FILE_NOT_FOUND; break;
+      case ELOOP: r = GRUB_ERR_SYMLINK_LOOP; break;
+      case EIO: r = GRUB_ERR_FILE_READ_ERROR; break;
+      default: r = GRUB_ERR_BAD_ARGUMENT; break;
+    }
+  return grub_error (r, strerror (errno));
+}
+
+/* Open a file named NAME and initialize FILE.  */
+/* File->data will contain retyped filedescriptor.  */
+static grub_err_t
+grub_host_open (struct grub_file *file, const char *name)
+{
+  struct stat statbuf;
+
+  if (host_mount (file->device))
+    return grub_errno;
+
+  file->data = (void *) open(name, O_RDONLY);
+  if (file->data == (void *) -1)
+    return errno2err();
+  fstat((int) file->data, &statbuf);
+  file->size = statbuf.st_size;
+  file->offset = 0;
+    
+  return 0;
+}
+
+static grub_err_t
+grub_host_close (grub_file_t file)
+{
+  close ((int) file->data);
+  file->data = (void *) -1;
+  return 0;
+}
+
+/* Read LEN bytes data from FILE into BUF.  */
+static grub_ssize_t
+grub_host_read (grub_file_t file, char *buf, grub_ssize_t len)
+{
+  int rv;
+
+  /* Maybe loop to get as most as possible should be here, may be not.  */
+  rv = read ((int) file->data, buf, len);
+  if (rv == -1)
+    return errno2err();
+  return rv;
+}
+
+
+static grub_err_t
+grub_host_dir (grub_device_t device, const char *path,
+              int (*hook) (const char *filename, int dir))
+{
+  DIR *dir;
+  struct dirent *dent;
+  struct stat stent;
+  char *pathbuf, *p;
+  unsigned pathlen;
+  unsigned maxname = 32;
+
+  if (host_mount (device))
+    return grub_errno;
+
+  pathlen = grub_strlen (path) + 1;
+  pathbuf = grub_malloc (pathlen + maxname);
+  if (pathbuf == 0)
+    goto mem_fail;
+  
+  grub_strcpy (pathbuf, path);
+  pathbuf [pathlen - 1] = '/';
+  pathbuf [pathlen] = 0;
+  
+  dir = opendir (pathbuf);
+  if (dir == 0)
+    goto errno_fail;
+
+  while ((dent = readdir (dir)) != 0)
+    {
+      if (grub_strlen (dent->d_name) >= maxname)
+       {
+         maxname = grub_strlen (dent->d_name);
+         p = grub_realloc (pathbuf, pathlen + maxname);
+         if (p == 0)
+           goto mem_fail;
+         pathbuf = p;
+       }
+      grub_strcpy (pathbuf + pathlen, dent->d_name);
+      lstat (pathbuf, &stent);
+      hook (dent->d_name, (stent.st_mode & S_IFMT) == S_IFDIR);
+    }
+
+  grub_free (pathbuf);
+  return 0;
+
+mem_fail:
+  grub_error (GRUB_ERR_OUT_OF_MEMORY, "Not enough memory.");
+  goto fail;
+
+errno_fail:
+  errno2err ();
+
+fail:
+  grub_free (pathbuf);
+  return grub_errno;
+}
+
+static grub_err_t
+grub_host_label (grub_device_t device, char **label)
+{
+  if (host_mount (device))
+    return grub_errno;
+  *label = 0;
+  return 0;
+}
+
+
+static struct grub_fs grub_host_fs =
+  {
+    .name = "host",
+    .dir = grub_host_dir,
+    .open = grub_host_open,
+    .read = grub_host_read,
+    .close = grub_host_close,
+    .label = grub_host_label,
+    .next = 0
+  };
+
+void
+grub_hostfs_init (void)
+{
+  grub_fs_register (&grub_host_fs);
+}
+
+void
+grub_hostfs_fini (void)
+{
+  grub_fs_unregister (&grub_host_fs);
+}
+
diff -rupN -x CVS grub2_x/include/grub/fakedisk.h 
grub2_wodiff/include/grub/fakedisk.h
--- grub2_x/include/grub/fakedisk.h     1970-01-01 01:00:00.000000000 +0100
+++ grub2_wodiff/include/grub/fakedisk.h        2004-08-13 00:08:40.000000000 
+0200
@@ -0,0 +1,32 @@
+/* fakedisk.h - fake disk device */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2004  Free Software Foundation, Inc.
+ *
+ *  GRUB 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 of the License, 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 GRUB; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#ifndef GRUB_FAKEDISK_HEADER
+#define GRUB_FAKEDISK_HEADER   1
+
+void grub_util_fakedisk_init (void);
+void grub_util_fakedisk_fini (void);
+
+#define GRUB_FAKEDISK_HOST_STRING "host"
+
+/* For hostfs to detect, that this is hostdisk.  */
+#define GRUB_IS_HOST_FAKEDISK(x) (grub_strcmp((x)->name, 
GRUB_FAKEDISK_HOST_STRING) == 0)
+
+#endif /* ! GRUB_FAKEDISK_HEADER */
diff -rupN -x CVS grub2_x/include/grub/fs.h grub2_wodiff/include/grub/fs.h
--- grub2_x/include/grub/fs.h   2004-08-08 14:18:18.000000000 +0200
+++ grub2_wodiff/include/grub/fs.h      2004-08-08 19:33:28.000000000 +0200
@@ -74,6 +74,8 @@ void grub_ufs_init (void);
 void grub_ufs_fini (void);
 void grub_minix_init (void);
 void grub_minix_fini (void);
+void grub_hostfs_init (void);
+void grub_hostfs_fini (void);
 #endif /* GRUB_UTIL */
 
 #endif /* ! GRUB_FS_HEADER */
diff -rupN -x CVS grub2_x/util/fakedisk.c grub2_wodiff/util/fakedisk.c
--- grub2_x/util/fakedisk.c     1970-01-01 01:00:00.000000000 +0100
+++ grub2_wodiff/util/fakedisk.c        2004-08-13 00:08:05.000000000 +0200
@@ -0,0 +1,96 @@
+/* fakedisk.c - fake disk device */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2004  Free Software Foundation, Inc.
+ *
+ *  GRUB 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 of the License, 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 GRUB; if not, write to the Free Software
+ *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <grub/disk.h>
+#include <grub/types.h>
+#include <grub/err.h>
+#include <grub/util/misc.h>
+#include <grub/misc.h>
+
+#include <grub/fakedisk.h>
+
+static int
+grub_util_fakedisk_iterate (int (*hook) (const char *name))
+{
+  if (hook (GRUB_FAKEDISK_HOST_STRING))
+    return 1;
+  else
+    return 0;
+}
+
+static grub_err_t
+grub_util_fakedisk_open (const char *name, grub_disk_t disk)
+{
+  if (grub_strcmp (name,GRUB_FAKEDISK_HOST_STRING) != 0)
+    return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "unknown disk %s", name);
+  disk->has_partitions = 0;
+  /* Id is irrelevant.  */
+  disk->id = -1;
+  /* This shoud be much greater than zero. Some fs claims that disk is
+   * totaly bad while fs-probe if total_sectors to low.  */
+  disk->total_sectors = 1234;
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_util_fakedisk_read (grub_disk_t disk __attribute__ ((unused)),
+                        unsigned long sector __attribute__ ((unused)),
+                        unsigned long size __attribute__ ((unused)),
+                        char *buf __attribute__ ((unused)))
+{
+  /* BAD_FS is here for filesystem probe to work.  */
+  grub_error (GRUB_ERR_BAD_FS, "cannot read from fakedisk %s", disk->name);
+  return grub_errno;
+}
+
+
+static grub_err_t
+grub_util_fakedisk_write (grub_disk_t disk __attribute__ ((unused)),
+                         unsigned long sector __attribute__ ((unused)),
+                         unsigned long size __attribute__ ((unused)),
+                         const char *buf __attribute__ ((unused)))
+{
+  grub_error (GRUB_ERR_BAD_FS, "cannot write to fakedisk %s", disk->name);
+  return grub_errno;
+}
+
+
+static struct grub_disk_dev grub_util_fakedisk_dev =
+  {
+    .name = "fakedisk",
+    .iterate = grub_util_fakedisk_iterate,
+    .open = grub_util_fakedisk_open,
+    .close = 0,
+    .read = grub_util_fakedisk_read,
+    .write = grub_util_fakedisk_write,
+    .next = 0
+  };
+
+void
+grub_util_fakedisk_init (void)
+{
+  grub_disk_dev_register (&grub_util_fakedisk_dev);
+}
+
+void
+grub_util_fakedisk_fini (void)
+{
+  grub_disk_dev_unregister (&grub_util_fakedisk_dev);
+}
diff -rupN -x CVS grub2_x/util/grub-emu.c grub2_wodiff/util/grub-emu.c
--- grub2_x/util/grub-emu.c     2004-08-08 14:18:18.000000000 +0200
+++ grub2_wodiff/util/grub-emu.c        2004-08-10 14:12:15.000000000 +0200
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2003  Free Software Foundation, Inc.
+ *  Copyright (C) 2003,2004  Free Software Foundation, Inc.
  *
  *  GRUB is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -35,6 +35,8 @@
 #include <grub/util/getroot.h>
 #include <grub/env.h>
 
+#include <grub/fakedisk.h>
+
 #ifdef __NetBSD__
 /* NetBSD uses /boot for its boot block.  */
 # define DEFAULT_DIRECTORY     "/grub"
@@ -154,7 +156,9 @@ main (int argc, char *argv[])
   
   /* XXX: This is a bit unportable.  */
   grub_util_biosdisk_init (args.dev_map);
+  grub_util_fakedisk_init ();
 
+  grub_hostfs_init ();
   /* Initialize the default modules.  */
   grub_fat_init ();
   grub_ext2_init ();
@@ -172,6 +176,7 @@ main (int argc, char *argv[])
   /* Start GRUB!  */
   grub_main ();
 
+  grub_util_fakedisk_fini ();
   grub_util_biosdisk_fini ();
   grub_normal_fini ();
   grub_ufs_fini ();
@@ -182,6 +187,7 @@ main (int argc, char *argv[])
   grub_cmp_fini ();
   grub_cat_fini ();
   grub_terminal_fini ();
+  grub_hostfs_fini ();
 
   return 0;
 }
##########################################################################

-- 
                                 Tomas 'ebi' Ebenlendr
                                 http://get.to/ebik
                                 PF 2004.61477452692