[PATCH 2/2] Using xattr to store translator record

[LastAvengers]

The purpose we implement xattr is storing passive translator in a
more general way. Now passive translator record now can be stored
using extended attributes. The new diskfs_{get,set}_translator()
functions are also compatibility with the "legacy" passive translator
record.

Thanks for antrik's suggestions.

--
Best regards,
Shengyu Zhang.

---
 ext2fs/inode.c | 156 +
 1 file changed, 80 insertions(+), 76 deletions(-)

diff --git a/ext2fs/inode.c b/ext2fs/inode.c
index ccc8d69..be163d5 100644
--- a/ext2fs/inode.c
+++ b/ext2fs/inode.c
@@ -26,6 +26,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /* these flags aren't actually defined by a header file yet, so temporarily
disable them if necessary.  */
@@ -540,81 +541,62 @@ error_t
 diskfs_set_translator (struct node *np, const char *name, unsigned namelen,
struct protid *cred)
 {
-  daddr_t blkno;
+  int len;
   error_t err;
-  char buf[block_size];
-  struct ext2_inode *di;
 
   assert (!diskfs_readonly);
 
-  if (sblock->s_creator_os != EXT2_OS_HURD)
-return EOPNOTSUPP;
-
-  if (namelen + 2 > block_size)
-return ENAMETOOLONG;
-
   err = diskfs_catch_exception ();
   if (err)
 return err;
 
-  di = dino_ref (np->cache_id);
-  blkno = di->i_translator;
-
-  if (namelen && !blkno)
+  /* If a old translator record found, clear it */
+  if (sblock->s_creator_os == EXT2_OS_HURD)
 {
-  /* Allocate block for translator */
-  blkno =
-ext2_new_block ((diskfs_node_disknode (np)->info.i_block_group
- * EXT2_BLOCKS_PER_GROUP (sblock))
-+ sblock->s_first_data_block,
-0, 0, 0);
-  if (blkno == 0)
+  daddr_t blkno;
+  struct ext2_inode *di;
+
+  di = dino_ref (np->cache_id);
+  blkno = di->i_translator;
+
+  if (blkno)
 {
-  dino_deref (di);
-  diskfs_end_catch_exception ();
-  return ENOSPC;
-}
+  ext2_warning("Old tranlator record found, clear it");
 
-  di->i_translator = blkno;
-  diskfs_node_disknode (np)->info_i_translator = blkno;
-  record_global_poke (di);
+  /* Clear block for translator going away. */
+  di->i_translator = 0;
+  diskfs_node_disknode (np)->info_i_translator = 0;
+  record_global_poke (di);
+  ext2_free_blocks (blkno, 1);
 
-  np->dn_stat.st_blocks += 1 << log2_stat_blocks_per_fs_block;
-  np->dn_set_ctime = 1;
-}
-  else if (!namelen && blkno)
-{
-  /* Clear block for translator going away. */
-  di->i_translator = 0;
-  diskfs_node_disknode (np)->info_i_translator = 0;
-  record_global_poke (di);
-  ext2_free_blocks (blkno, 1);
-
-  np->dn_stat.st_blocks -= 1 << log2_stat_blocks_per_fs_block;
-  np->dn_stat.st_mode &= ~S_IPTRANS;
-  np->dn_set_ctime = 1;
+  np->dn_stat.st_blocks -= 1 << log2_stat_blocks_per_fs_block;
+  np->dn_stat.st_mode &= ~S_IPTRANS;
+  np->dn_set_ctime = 1;
+}
+  else
+dino_deref (di);
 }
-  else
-dino_deref (di);
-
-  if (namelen)
-{
-  void *blkptr;
 
-  buf[0] = namelen & 0xFF;
-  buf[1] = (namelen >> 8) & 0xFF;
-  memcpy (buf + 2, name, namelen);
+  /* Use xattr to store translator record, with key "gnu.translator" */
+  err = ext2_get_xattr(np, "gnu.translator", NULL, &len);
+  if (err && err != ENODATA)
+return err;
 
-  blkptr = disk_cache_block_ref (blkno);
-  memcpy (blkptr, buf, block_size);
-  record_global_poke (blkptr);
+  if (namelen && err == ENODATA)
+{
+  err = ext2_set_xattr(np, "gnu.translator", name, namelen, XATTR_CREATE);
 
   np->dn_stat.st_mode |= S_IPTRANS;
   np->dn_set_ctime = 1;
 }
+  else if (!namelen && !err)
+{
+  err = ext2_set_xattr(np, "gnu.translator", NULL, 0, 0);
+}
 
   diskfs_end_catch_exception ();
   return err;
+
 }
 
 /* Implement the diskfs_get_translator callback from the diskfs library.
@@ -623,37 +605,59 @@ error_t
 diskfs_get_translator (struct node *np, char **namep, unsigned *namelen)
 {
   error_t err = 0;
-  daddr_t blkno;
-  unsigned datalen;
-  void *transloc;
-  struct ext2_inode *di;
-
-  assert (sblock->s_creator_os == EXT2_OS_HURD);
+  int datalen;
 
   err = diskfs_catch_exception ();
   if (err)
 return err;
 
-  di = dino_ref (np->cache_id);
-  blkno = di->i_translator;
-  dino_deref (di);
-  assert (blkno);
-  transloc = disk_cache_block_ref (blkno);
-
-  datalen =
-((unsigned char *)transloc)[0] + (((unsigned char *)transloc)[1] << 8);
-  if (datalen > block_size - 2)
-err = EFTYPE;/* ? */
-  else
+  /* If a old translator record found, read it firstly */
+  if (sblock->s_creator_os == EXT2_OS_HURD)
 {
-  *namep = malloc (datalen);
-  if (!*namep)
-err = ENOMEM;
-  else
-memcpy (*namep, transloc + 2, datalen);
+  daddr_t blkno;
+  void *transloc;
+  struct ext2_inode *di;
+
+  di = dino_ref (np->cache_id);
+  blkno = di->i_translator

[PATCH 1/2] xattr support for ext2fs

[LastAvengers]

Hi all,
Here is the result of the first stage of my GSoC project.
The xattr support for ext2fs has implemented.

This patch is base on cascardo's previous work[1],
Only 2 namespaces ("user." and  "gnu.") are supported,
as other namespaces are useless on hurd now.

thanks for braunr and teythoon's mentoring ;)

[1]: https://savannah.gnu.org/patch/?5126
--
Best regards,
Shengyu Zhang.

---
 ext2fs/Makefile  |   3 +-
 ext2fs/ext2_fs.h |   3 +-
 ext2fs/ext2fs.h  |  13 +
 ext2fs/ialloc.c  |   2 +
 ext2fs/xattr.c   | 866 +++
 ext2fs/xattr.h   |  85 ++
 6 files changed, 970 insertions(+), 2 deletions(-)
 create mode 100644 ext2fs/xattr.c
 create mode 100644 ext2fs/xattr.h

diff --git a/ext2fs/Makefile b/ext2fs/Makefile
index 88f8f46..0c2f4a2 100644
--- a/ext2fs/Makefile
+++ b/ext2fs/Makefile
@@ -21,7 +21,8 @@ makemode := server
 
 target = ext2fs
 SRCS = balloc.c dir.c ext2fs.c getblk.c hyper.c ialloc.c \
-   inode.c pager.c pokel.c truncate.c storeinfo.c msg.c xinl.c
+   inode.c pager.c pokel.c truncate.c storeinfo.c msg.c xinl.c \
+   xattr.c
 OBJS = $(SRCS:.c=.o)
 HURDLIBS = diskfs pager iohelp fshelp store ports ihash shouldbeinlibc
 LDLIBS = -lpthread $(and $(HAVE_LIBBZ2),-lbz2) $(and $(HAVE_LIBZ),-lz)
diff --git a/ext2fs/ext2_fs.h b/ext2fs/ext2_fs.h
index b1caeef..019ba15 100644
--- a/ext2fs/ext2_fs.h
+++ b/ext2fs/ext2_fs.h
@@ -462,6 +462,7 @@ struct ext2_super_block {
 ( EXT2_SB(sb)->s_feature_incompat & (mask) )
 
 #define EXT2_FEATURE_COMPAT_DIR_PREALLOC0x0001
+#define EXT2_FEATURE_COMPAT_EXT_ATTR0x0008
 
 #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER0x0001
 #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE0x0002
@@ -470,7 +471,7 @@ struct ext2_super_block {
 #define EXT2_FEATURE_INCOMPAT_COMPRESSION0x0001
 #define EXT2_FEATURE_INCOMPAT_FILETYPE0x0002
 
-#define EXT2_FEATURE_COMPAT_SUPP0
+#define EXT2_FEATURE_COMPAT_SUPPEXT2_FEATURE_COMPAT_EXT_ATTR
 #define EXT2_FEATURE_INCOMPAT_SUPPEXT2_FEATURE_INCOMPAT_FILETYPE
 #define EXT2_FEATURE_RO_COMPAT_SUPP(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
  EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
diff --git a/ext2fs/ext2fs.h b/ext2fs/ext2fs.h
index 070d5bd..bbf7a0c 100644
--- a/ext2fs/ext2fs.h
+++ b/ext2fs/ext2fs.h
@@ -17,6 +17,9 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
 
+#ifndef _EXT2FS_H
+#define _EXT2FS_H
+
 #include 
 #include 
 #include 
@@ -571,3 +574,13 @@ extern void _ext2_panic (const char *, const char *, ...)
 
 extern void ext2_warning (const char *, ...)
  __attribute__ ((format (printf, 1, 2)));
+
+/*  */
+/* xattr.c */
+
+error_t ext2_list_xattr (struct node *np, char *buffer, int *len);
+error_t ext2_get_xattr (struct node *np, const char *name, char *value, int 
*len);
+error_t ext2_set_xattr (struct node *np, const char *name, const char *value, 
int len, int flags);
+error_t ext2_free_xattr_block (struct node *np);
+
+#endif
diff --git a/ext2fs/ialloc.c b/ext2fs/ialloc.c
index 2809371..71bfb8c 100644
--- a/ext2fs/ialloc.c
+++ b/ext2fs/ialloc.c
@@ -62,6 +62,8 @@ diskfs_free_node (struct node *np, mode_t old_mode)
 
   ext2_debug ("freeing inode %u", inum);
 
+  ext2_free_xattr_block (np);
+
   pthread_spin_lock (&global_lock);
 
   if (inum < EXT2_FIRST_INO (sblock) || inum > sblock->s_inodes_count)
diff --git a/ext2fs/xattr.c b/ext2fs/xattr.c
new file mode 100644
index 000..1e298dcb
--- /dev/null
+++ b/ext2fs/xattr.c
@@ -0,0 +1,866 @@
+ /* Ext2 support for extended attributes
+
+   Copyright (C) 2006, 2016 Free Software Foundation, Inc.
+
+   Written by Thadeu Lima de Souza Cascardo 
+   and Shengyu Zhang 
+
+   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 "ext2fs.h"
+#include "xattr.h"
+#include 
+#include 
+#include 
+
+struct _xattr_prefix
+{
+  int index;
+  char *prefix;
+  ssize_t size;
+};
+
+/* Prefixes are represented as numbers when stored in ext2 filesystems. */
+struct _xattr_prefix
+xattr_prefixes[] =
+{
+  {
+  1, "user.", sizeof "user." - 1},
+  {
+  7, "gnu.", sizeof "gnu." - 1},
+  {
+  0, NULL, 0}
+};
+
+/*
+ * Given an attribute name in full_name, the ext2 number (index) and
+ * suffix name (name) are gi

[bug #48372] read with size 0 from fifo blocks

[Kalle Olavi Niemitalo]

Follow-up Comment #4, bug #48372 (project hurd):

IEEE Std 1003.1, 2013 Edition makes nbyte==0 a special case in the read and
pread functions, but I don't see similar special cases in the recv, recvfrom,
and recvmsg functions.  AFAICT, those should consume the message from a
message-based socket even if the buffer has zero length, unless MSG_PEEK is
specified.

pflocal/io.c (S_io_read) calls pipe_read, which calls pipe_recv (pipe,
noblock, 0, source, data, data_len, amount, 0,0,0,0).

pflocal/socket.c (S_socket_recv) calls pipe_recv (..., control, control_len,
ports, num_ports).  In hurd/socket.defs (socket_recv), those correspond to
output parameters, so I believe they are not included in the request message
and the mig-generated code will ensure that e.g. control != NULL.

I think pipe_read should then apply the shortcut behavior only if (amount == 0
&& data_only).  That way, the change would not affect recv, recvfrom, and
recvmsg.

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