Re: [PATCH] cpio and tar filesystem

[Bean]

On Dec 24, 2007 5:48 AM, Robert Millan <address@hidden> wrote:
>Perhaps it'd be a good idea to move the arch-independant part of
>grub_emu_SOURCES to common.rmk (as grub_emu_SOURCES += foo), to avoid
>having to update all the files so often ...

yes, but i think it should be in a separate patch.

> > +struct HEAD_USTAR
> > +{
> > +  char       name[100];
> > +  char       mode[8];
> > +  char       uid[8];
> > +  char       gid[8];
> > +  char       size[12];
> > +  char       mtime[12];
> > +  char       chksum[8];
> > +  char       typeflag;
> > +  char       linkname[100];
> > +  char       magic[6];
> > +  char       version[2];
> > +  char       uname[32];
> > +  char       gname[32];
> > +  char       devmajor[8];
> > +  char       devminor[8];
> > +  char       prefix[155];
>
> These tabs should be spaces.
done.

>
> > +      if (grub_disk_read (data->disk, 0, data->hofs, sizeof(hd), 
> > (char*)&hd))
> > [...]
> > +      if (grub_disk_read (data->disk, 0, data->hofs, sizeof(hd), 
> > (char*)&hd))
>
> `(char *) &hd' here (same for all other casts).
>
> Btw, this line seems to be the same on both cases.  It can be moved out of
> `if (data->mode == MODE_BCPIO)' to save some space?
>

In fact, it's not the same, in the first case, hd is of type
HEAD_BCPIO, while in the second case, hd is of type HEAD_USTAR.The two
structure has different size.

> > +      if (hd.namesize & 1)
> > +        hd.namesize++;
> > [...]
> > +      if (data->size & 1)
> > +        (*ofs)++;
>
> I find this confusing.  AFAICT `hd.namesize == 1' would archieve the same and
> seems to be more consistent with your use of this variable as a counter.
>
When the name size is odd number, cpio pad another byte to make it
word align, and the same apply to file size. However, I want to keep
the original file size, so it use (*ofs)++ instead of data->size++.

> > +      if ((*name = grub_malloc (hd.namesize))==NULL)
> > [...]
> > +      if ((*name = grub_strdup (hd.name))==NULL)
>
> Please add some spaces: ` == NULL'
>
> > +      if (grub_memcmp(hd.magic, MAGIC_USTAR, sizeof(MAGIC_USTAR) - 1))
> > [...]
> > +      data->size = grub_strtoul(hd.size, NULL, 8);
>
> `grub_memcmp (', `grub_strtoul (', etc.  Same for other function calls.
>
> > +  return (grub_disk_read (data->disk, 0, data->dofs + file->offset,
> > +                          len, buf))?-1:len;
>
> ` ? -1 : len'
>
done.

> > +#ifndef GRUB_UTIL
> > +  grub_dl_unref (my_mod);
> > +#endif
> > [...]
> > +#ifndef GRUB_UTIL
> > +  my_mod = mod;
> > +#endif
>
> Are you sure these are still needed?  We have a few modules that use them but
> AFAIK are not necessary at this time.

This is needed, the my_mod variable is used to stored the module
pointer, and we need it to increase the module reference when a file
is opened, so that the modules can't be unloaded.

Here is the new patch.

2007-12-24  Bean  <address@hidden>

        * conf/common.rmk (pkgdata_MODULES): Add cpio.mod.
        (cpio_mod_SOURCES): New variable.
        (cpio_mod_CFLAGS): Likewise.
        (cpio_mod_LDFLAGS): Likewise.

        * fs/cpio.c: New file.

        * conf/i386-pc.rmk (grub_emu_SOURCES): Add cpio.c.

        * conf/i386-efi.rmk (grub_emu_SOURCES): Likewise.

        * conf/i386-linuxbios.rmk (grub_emu_SOURCES): Likewise.

        * conf/powerpc-ieee1275.rmk (grub_emu_SOURCES): Likewise.


diff --git a/conf/common.rmk b/conf/common.rmk
index 0e6b81b..72edb37 100644
--- a/conf/common.rmk
+++ b/conf/common.rmk
@@ -81,7 +81,7 @@ update-grub_DATA += util/grub.d/README
 # Filing systems.
 pkgdata_MODULES += fshelp.mod fat.mod ufs.mod ext2.mod ntfs.mod                
\
        ntfscomp.mod minix.mod hfs.mod jfs.mod iso9660.mod xfs.mod      \
-       affs.mod sfs.mod hfsplus.mod
+       affs.mod sfs.mod hfsplus.mod cpio.mod

 # For fshelp.mod.
 fshelp_mod_SOURCES = fs/fshelp.c
@@ -153,6 +153,11 @@ hfsplus_mod_SOURCES = fs/hfsplus.c
 hfsplus_mod_CFLAGS = $(COMMON_CFLAGS)
 hfsplus_mod_LDFLAGS = $(COMMON_LDFLAGS)

+# For cpio.mod.
+cpio_mod_SOURCES = fs/cpio.c
+cpio_mod_CFLAGS = $(COMMON_CFLAGS)
+cpio_mod_LDFLAGS = $(COMMON_LDFLAGS)
+
 # Partition maps.
 pkgdata_MODULES += amiga.mod apple.mod pc.mod sun.mod acorn.mod gpt.mod

diff --git a/conf/i386-efi.rmk b/conf/i386-efi.rmk
index 305cbe4..397cfbb 100644
--- a/conf/i386-efi.rmk
+++ b/conf/i386-efi.rmk
@@ -51,7 +51,7 @@ grub_emu_SOURCES = commands/boot.c commands/cat.c
commands/cmp.c  \
        disk/loopback.c                                                 \
        fs/affs.c fs/ext2.c fs/fat.c fs/fshelp.c fs/hfs.c fs/iso9660.c  \
        fs/jfs.c fs/minix.c fs/sfs.c fs/ufs.c fs/xfs.c fs/hfsplus.c     \
-       fs/ntfs.c fs/ntfscomp.c                                         \
+       fs/ntfs.c fs/ntfscomp.c fs/cpio.c                               \
        io/gzio.c                                                       \
        kern/device.c kern/disk.c kern/dl.c kern/elf.c kern/env.c       \
        kern/err.c                                                      \
diff --git a/conf/i386-linuxbios.rmk b/conf/i386-linuxbios.rmk
index 8b98d3b..c33d937 100644
--- a/conf/i386-linuxbios.rmk
+++ b/conf/i386-linuxbios.rmk
@@ -76,7 +76,7 @@ grub_emu_SOURCES = commands/boot.c commands/cat.c
commands/cmp.c  \
        disk/host.c disk/loopback.c     disk/raid.c disk/lvm.c          \
        fs/affs.c fs/ext2.c fs/fat.c fs/fshelp.c fs/hfs.c fs/iso9660.c  \
        fs/jfs.c fs/minix.c fs/sfs.c fs/ufs.c fs/xfs.c fs/hfsplus.c     \
-       fs/ntfs.c fs/ntfscomp.c                                         \
+       fs/ntfs.c fs/ntfscomp.c fs/cpio.c                               \
        io/gzio.c                                                       \
        kern/device.c kern/disk.c kern/dl.c kern/elf.c kern/env.c       \
        kern/err.c                                                      \
diff --git a/conf/i386-pc.rmk b/conf/i386-pc.rmk
index 8c100d7..8e0f31b 100644
--- a/conf/i386-pc.rmk
+++ b/conf/i386-pc.rmk
@@ -103,7 +103,7 @@ grub_emu_SOURCES = commands/boot.c commands/cat.c
commands/cmp.c  \
        disk/host.c disk/loopback.c     disk/raid.c disk/lvm.c          \
        fs/affs.c fs/ext2.c fs/fat.c fs/fshelp.c fs/hfs.c fs/iso9660.c  \
        fs/jfs.c fs/minix.c fs/sfs.c fs/ufs.c fs/xfs.c fs/hfsplus.c     \
-       fs/ntfs.c fs/ntfscomp.c                                         \
+       fs/ntfs.c fs/ntfscomp.c fs/cpio.c                               \
        io/gzio.c                                                       \
        kern/device.c kern/disk.c kern/dl.c kern/elf.c kern/env.c       \
        kern/err.c                                                      \
diff --git a/conf/powerpc-ieee1275.rmk b/conf/powerpc-ieee1275.rmk
index eb440f1..af0773b 100644
--- a/conf/powerpc-ieee1275.rmk
+++ b/conf/powerpc-ieee1275.rmk
@@ -62,7 +62,7 @@ grub_emu_SOURCES = commands/boot.c commands/cat.c
commands/cmp.c  \
        disk/loopback.c                                                 \
        fs/affs.c fs/ext2.c fs/fat.c fs/fshelp.c fs/hfs.c fs/iso9660.c  \
        fs/jfs.c fs/minix.c fs/sfs.c fs/ufs.c fs/xfs.c fs/hfsplus.c     \
-       fs/ntfs.c fs/ntfscomp.c                                         \
+       fs/ntfs.c fs/ntfscomp.c fs/cpio.c                               \
        io/gzio.c                                                       \
        kern/device.c kern/disk.c kern/dl.c kern/elf.c kern/env.c       \
        kern/err.c kern/file.c kern/fs.c kern/loader.c kern/main.c      \
diff --git a/fs/cpio.c b/fs/cpio.c
new file mode 100755
index 0000000..48e0514
--- /dev/null
+++ b/fs/cpio.c
@@ -0,0 +1,348 @@
+/* cpio.c - cpio and tar filesystem.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2007 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/file.h>
+#include <grub/mm.h>
+#include <grub/misc.h>
+#include <grub/disk.h>
+#include <grub/dl.h>
+
+#define        MAGIC_BCPIO     070707
+
+struct HEAD_BCPIO
+{
+  grub_uint16_t magic;
+  grub_uint16_t dev;
+  grub_uint16_t ino;
+  grub_uint16_t mode;
+  grub_uint16_t uid;
+  grub_uint16_t gid;
+  grub_uint16_t nlink;
+  grub_uint16_t rdev;
+  grub_uint16_t mtime_1;
+  grub_uint16_t mtime_2;
+  grub_uint16_t namesize;
+  grub_uint16_t filesize_1;
+  grub_uint16_t filesize_2;
+} __attribute__ ((packed));
+
+#define MAGIC_USTAR    "ustar"
+
+struct HEAD_USTAR
+{
+  char name[100];
+  char mode[8];
+  char uid[8];
+  char gid[8];
+  char size[12];
+  char mtime[12];
+  char chksum[8];
+  char typeflag;
+  char linkname[100];
+  char magic[6];
+  char version[2];
+  char uname[32];
+  char gname[32];
+  char devmajor[8];
+  char devminor[8];
+  char prefix[155];
+} __attribute__ ((packed));
+
+#define HEAD_LENG      sizeof(struct HEAD_USTAR)
+
+#define MODE_BCPIO     1
+#define MODE_USTAR     2
+
+struct grub_cpio_data
+{
+  grub_disk_t disk;
+  grub_uint32_t hofs;
+  grub_uint32_t dofs;
+  grub_uint32_t size;
+  int mode;
+};
+
+#ifndef GRUB_UTIL
+static grub_dl_t my_mod;
+#endif
+
+static grub_err_t
+grub_cpio_find_file (struct grub_cpio_data *data, char **name,
+                    grub_uint32_t * ofs)
+{
+  if (data->mode == MODE_BCPIO)
+    {
+      struct HEAD_BCPIO hd;
+
+      if (grub_disk_read
+         (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
+       return grub_errno;
+
+      if (hd.magic != MAGIC_BCPIO)
+       return grub_error (GRUB_ERR_BAD_FS, "Invalid cpio archive");
+
+      data->size = (((grub_uint32_t) hd.filesize_1) << 16) + hd.filesize_2;
+      if (data->size == 0)
+       {
+         *ofs = 0;
+         return GRUB_ERR_NONE;
+       }
+
+      if (hd.namesize & 1)
+       hd.namesize++;
+
+      if ((*name = grub_malloc (hd.namesize)) == NULL)
+       return grub_errno;
+
+      if (grub_disk_read (data->disk, 0, data->hofs + sizeof (hd),
+                         hd.namesize, *name))
+       {
+         grub_free (*name);
+         return grub_errno;
+       }
+
+      data->dofs = data->hofs + sizeof (hd) + hd.namesize;
+      *ofs = data->dofs + data->size;
+      if (data->size & 1)
+       (*ofs)++;
+    }
+  else
+    {
+      struct HEAD_USTAR hd;
+
+      if (grub_disk_read
+         (data->disk, 0, data->hofs, sizeof (hd), (char *) &hd))
+       return grub_errno;
+
+      if (!hd.name[0])
+       {
+         *ofs = 0;
+         return GRUB_ERR_NONE;
+       }
+
+      if (grub_memcmp (hd.magic, MAGIC_USTAR, sizeof (MAGIC_USTAR) - 1))
+       return grub_error (GRUB_ERR_BAD_FS, "Invalid tar archive");
+
+      if ((*name = grub_strdup (hd.name)) == NULL)
+       return grub_errno;
+
+      data->size = grub_strtoul (hd.size, NULL, 8);
+      data->dofs = data->hofs + GRUB_DISK_SECTOR_SIZE;
+      *ofs = data->dofs + ((data->size + GRUB_DISK_SECTOR_SIZE - 1) &
+                          ~(GRUB_DISK_SECTOR_SIZE - 1));
+    }
+  return GRUB_ERR_NONE;
+}
+
+static struct grub_cpio_data *
+grub_cpio_mount (grub_disk_t disk)
+{
+  char hd[HEAD_LENG];
+  struct grub_cpio_data *data;
+  int mode;
+
+  if (grub_disk_read (disk, 0, 0, sizeof (hd), hd))
+    goto fail;
+
+  if (((struct HEAD_BCPIO *) hd)->magic == MAGIC_BCPIO)
+    mode = MODE_BCPIO;
+  else if (!grub_memcmp (((struct HEAD_USTAR *) hd)->magic, MAGIC_USTAR,
+                        sizeof (MAGIC_USTAR) - 1))
+    mode = MODE_USTAR;
+  else
+    goto fail;
+
+  data = (struct grub_cpio_data *) grub_malloc (sizeof (*data));
+  if (!data)
+    goto fail;
+
+  data->disk = disk;
+  data->mode = mode;
+
+  return data;
+
+fail:
+  grub_error (GRUB_ERR_BAD_FS, "not a cpio filesystem");
+  return 0;
+}
+
+static grub_err_t
+grub_cpio_dir (grub_device_t device, const char *path,
+              int (*hook) (const char *filename, int dir))
+{
+  struct grub_cpio_data *data;
+  grub_uint32_t ofs;
+  char *prev, *name, *np;
+  int len;
+
+#ifndef GRUB_UTIL
+  grub_dl_ref (my_mod);
+#endif
+
+  prev = 0;
+
+  data = grub_cpio_mount (device->disk);
+  if (!data)
+    goto fail;
+
+  np = path + 1;
+  len = grub_strlen (path) - 1;
+
+  data->hofs = 0;
+  while (1)
+    {
+      if (grub_cpio_find_file (data, &name, &ofs))
+       goto fail;
+
+      if (!ofs)
+       break;
+
+      if (grub_memcmp (np, name, len) == 0)
+       {
+         char *p, *n;
+
+         n = name + len;
+         if (*n == '/')
+           n++;
+
+         p = grub_strchr (name + len, '/');
+         if (p)
+           *p = 0;
+
+         if ((!prev) || (grub_strcmp (prev, name) != 0))
+           {
+             hook (name + len, p != NULL);
+             if (prev)
+               grub_free (prev);
+             prev = name;
+           }
+         else
+           grub_free (name);
+       }
+      data->hofs = ofs;
+    }
+
+fail:
+
+  if (prev)
+    grub_free (prev);
+
+  if (data)
+    grub_free (data);
+
+#ifndef GRUB_UTIL
+  grub_dl_unref (my_mod);
+#endif
+
+  return grub_errno;
+}
+
+static grub_err_t
+grub_cpio_open (grub_file_t file, const char *name)
+{
+  struct grub_cpio_data *data;
+  grub_uint32_t ofs;
+  char *fn;
+
+#ifndef GRUB_UTIL
+  grub_dl_ref (my_mod);
+#endif
+
+  data = grub_cpio_mount (file->device->disk);
+  if (!data)
+    goto fail;
+
+  data->hofs = 0;
+  while (1)
+    {
+      if (grub_cpio_find_file (data, &fn, &ofs))
+       goto fail;
+
+      if (!ofs)
+       break;
+
+      if (grub_strcmp (name + 1, fn) == 0)
+       {
+         file->data = data;
+         file->size = data->size;
+         grub_free (fn);
+
+         return GRUB_ERR_NONE;
+       }
+
+      grub_free (fn);
+      data->hofs = ofs;
+    }
+
+fail:
+
+  if (data)
+    grub_free (data);
+
+#ifndef GRUB_UTIL
+  grub_dl_unref (my_mod);
+#endif
+
+  return grub_errno;
+}
+
+static grub_ssize_t
+grub_cpio_read (grub_file_t file, char *buf, grub_size_t len)
+{
+  struct grub_cpio_data *data;
+
+  data = file->data;
+  return (grub_disk_read (data->disk, 0, data->dofs + file->offset,
+                         len, buf)) ? -1 : len;
+}
+
+static grub_err_t
+grub_cpio_close (grub_file_t file)
+{
+  grub_free (file->data);
+
+#ifndef GRUB_UTIL
+  grub_dl_unref (my_mod);
+#endif
+
+  return grub_errno;
+}
+
+static struct grub_fs grub_cpio_fs = {
+  .name = "cpiofs",
+  .dir = grub_cpio_dir,
+  .open = grub_cpio_open,
+  .read = grub_cpio_read,
+  .close = grub_cpio_close,
+  .label = 0,
+  .next = 0
+};
+
+GRUB_MOD_INIT (cpio)
+{
+  grub_fs_register (&grub_cpio_fs);
+#ifndef GRUB_UTIL
+  my_mod = mod;
+#endif
+}
+
+GRUB_MOD_FINI (cpio)
+{
+  grub_fs_unregister (&grub_cpio_fs);
+}


-- 
Bean