Support for Linux extended attributes.

This commit adds six calls to support Linux extended attributes.
They are:
  getxattrs     list all extended attributes for a file or directory
  setxattr      add/replace an extended attribute
  removexattr   remove an extended attribute
  lgetxattrs    \
  lsetxattr     (same as above, but operate on symbolic links)
  lremovexattr  /

See attr(5) for more information.

This also adds support for the FBuffer field type, which maps to
an XDR opaque<> or a C (int, char *) pair.
This commit is contained in:
Richard W.M. Jones
2009-07-14 11:50:55 +01:00
parent 7b3c76c951
commit 2600359b9b
6 changed files with 416 additions and 5 deletions

1
.gitignore vendored
View File

@@ -96,6 +96,7 @@ java/com/redhat/et/libguestfs/Stat.java
java/com/redhat/et/libguestfs/StatVFS.java
java/com/redhat/et/libguestfs/Version.java
java/com/redhat/et/libguestfs/VG.java
java/com/redhat/et/libguestfs/XAttr.java
java/doc-stamp
java/Makefile.inc
*.la

View File

@@ -65,6 +65,7 @@ guestfsd_SOURCES = \
umask.c \
upload.c \
wc.c \
xattr.c \
zero.c \
zerofree.c \
$(top_builddir)/../src/guestfs_protocol.h \

View File

@@ -63,7 +63,10 @@ AC_CHECK_LIB([portablexdr],[xdrmem_create],[],[
])
dnl Functions which may not be available in older distributions.
AC_CHECK_FUNCS([futimens])
AC_CHECK_FUNCS([futimens listxattr llistxattr getxattr lgetxattr setxattr lsetxattr removexattr lremovexattr])
dnl Headers.
AC_CHECK_HEADERS([attr/xattr.h])
dnl Produce output files.
AC_CONFIG_HEADERS([config.h])

284
daemon/xattr.c Normal file
View File

@@ -0,0 +1,284 @@
/* libguestfs - the guestfsd daemon
* Copyright (C) 2009 Red Hat 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 <config.h>
#include <stdio.h>
#include <unistd.h>
#ifdef HAVE_ATTR_XATTR_H
#include <attr/xattr.h>
#include "../src/guestfs_protocol.h"
#include "daemon.h"
#include "actions.h"
static guestfs_int_xattr_list *getxattrs (char *path, ssize_t (*listxattr) (const char *path, char *list, size_t size), ssize_t (*getxattr) (const char *path, const char *name, void *value, size_t size));
static int _setxattr (char *xattr, char *val, int vallen, char *path, int (*setxattr) (const char *path, const char *name, const void *value, size_t size, int flags));
static int _removexattr (char *xattr, char *path, int (*removexattr) (const char *path, const char *name));
guestfs_int_xattr_list *
do_getxattrs (char *path)
{
#if defined(HAVE_LISTXATTR) && defined(HAVE_GETXATTR)
return getxattrs (path, listxattr, getxattr);
#else
reply_with_error ("getxattrs: no support for listxattr and getxattr");
return NULL;
#endif
}
guestfs_int_xattr_list *
do_lgetxattrs (char *path)
{
#if defined(HAVE_LLISTXATTR) && defined(HAVE_LGETXATTR)
return getxattrs (path, llistxattr, lgetxattr);
#else
reply_with_error ("lgetxattrs: no support for llistxattr and lgetxattr");
return NULL;
#endif
}
int
do_setxattr (char *xattr, char *val, int vallen, char *path)
{
#if defined(HAVE_SETXATTR)
return _setxattr (xattr, val, vallen, path, setxattr);
#else
reply_with_error ("setxattr: no support for setxattr");
return -1;
#endif
}
int
do_lsetxattr (char *xattr, char *val, int vallen, char *path)
{
#if defined(HAVE_LSETXATTR)
return _setxattr (xattr, val, vallen, path, lsetxattr);
#else
reply_with_error ("lsetxattr: no support for lsetxattr");
return -1;
#endif
}
int
do_removexattr (char *xattr, char *path)
{
#if defined(HAVE_REMOVEXATTR)
return _removexattr (xattr, path, removexattr);
#else
reply_with_error ("removexattr: no support for removexattr");
return -1;
#endif
}
int
do_lremovexattr (char *xattr, char *path)
{
#if defined(HAVE_LREMOVEXATTR)
return _removexattr (xattr, path, lremovexattr);
#else
reply_with_error ("lremovexattr: no support for lremovexattr");
return -1;
#endif
}
static guestfs_int_xattr_list *
getxattrs (char *path,
ssize_t (*listxattr) (const char *path, char *list, size_t size),
ssize_t (*getxattr) (const char *path, const char *name,
void *value, size_t size))
{
ssize_t len, vlen;
char *buf = NULL;
int i, j;
guestfs_int_xattr_list *r = NULL;
NEED_ROOT (NULL);
ABS_PATH (path, NULL);
CHROOT_IN;
len = listxattr (path, NULL, 0);
CHROOT_OUT;
if (len == -1) {
reply_with_perror ("listxattr");
goto error;
}
buf = malloc (len);
if (buf == NULL) {
reply_with_perror ("malloc");
goto error;
}
CHROOT_IN;
len = listxattr (path, buf, len);
CHROOT_OUT;
if (len == -1) {
reply_with_perror ("listxattr");
goto error;
}
r = calloc (1, sizeof (*r));
if (r == NULL) {
reply_with_perror ("malloc");
goto error;
}
/* What we get from the kernel is a string "foo\0bar\0baz" of length
* len. First count the strings.
*/
r->guestfs_int_xattr_list_len = 0;
for (i = 0; i < len; i += strlen (&buf[i]) + 1)
r->guestfs_int_xattr_list_len++;
r->guestfs_int_xattr_list_val =
calloc (r->guestfs_int_xattr_list_len, sizeof (guestfs_int_xattr));
if (r->guestfs_int_xattr_list_val == NULL) {
reply_with_perror ("calloc");
goto error;
}
for (i = 0, j = 0; i < len; i += strlen (&buf[i]) + 1, ++j) {
CHROOT_IN;
vlen = getxattr (path, &buf[i], NULL, 0);
CHROOT_OUT;
if (vlen == -1) {
reply_with_perror ("getxattr");
goto error;
}
r->guestfs_int_xattr_list_val[j].attrname = strdup (&buf[i]);
r->guestfs_int_xattr_list_val[j].attrval.attrval_val = malloc (vlen);
r->guestfs_int_xattr_list_val[j].attrval.attrval_len = vlen;
if (r->guestfs_int_xattr_list_val[j].attrname == NULL ||
r->guestfs_int_xattr_list_val[j].attrval.attrval_val == NULL) {
reply_with_perror ("malloc");
goto error;
}
CHROOT_IN;
vlen = getxattr (path, &buf[i],
r->guestfs_int_xattr_list_val[j].attrval.attrval_val,
vlen);
CHROOT_OUT;
if (vlen == -1) {
reply_with_perror ("getxattr");
goto error;
}
}
free (buf);
return r;
error:
free (buf);
if (r) {
if (r->guestfs_int_xattr_list_val)
for (i = 0; i < r->guestfs_int_xattr_list_len; ++i) {
free (r->guestfs_int_xattr_list_val[i].attrname);
free (r->guestfs_int_xattr_list_val[i].attrval.attrval_val);
}
free (r->guestfs_int_xattr_list_val);
}
free (r);
return NULL;
}
static int
_setxattr (char *xattr, char *val, int vallen, char *path,
int (*setxattr) (const char *path, const char *name,
const void *value, size_t size, int flags))
{
int r;
CHROOT_IN;
r = setxattr (path, xattr, val, vallen, 0);
CHROOT_OUT;
if (r == -1) {
reply_with_perror ("setxattr");
return -1;
}
return 0;
}
static int
_removexattr (char *xattr, char *path,
int (*removexattr) (const char *path, const char *name))
{
int r;
CHROOT_IN;
r = removexattr (path, xattr);
CHROOT_OUT;
if (r == -1) {
reply_with_perror ("removexattr");
return -1;
}
return 0;
}
#else /* !HAVE_ATTR_XATTR_H */
guestfs_int_xattr_list *
do_getxattrs (char *path)
{
reply_with_error ("getxattrs: no support for xattrs");
return NULL;
}
guestfs_int_xattr_list *
do_lgetxattrs (char *path)
{
reply_with_error ("lgetxattrs: no support for xattrs");
return NULL;
}
int
do_setxattr (char *xattr, char *val, int vallen, char *path)
{
reply_with_error ("setxattr: no support for xattrs");
return -1;
}
int
do_lsetxattr (char *xattr, char *val, int vallen, char *path)
{
reply_with_error ("lsetxattr: no support for xattrs");
return -1;
}
int
do_removexattr (char *xattr, char *path)
{
reply_with_error ("removexattr: no support for xattrs");
return -1;
}
int
do_lremovexattr (char *xattr, char *path)
{
reply_with_error ("lremovexattr: no support for xattrs");
return -1;
}
#endif /* !HAVE_ATTR_XATTR_H */

View File

@@ -1 +1 @@
140
146

View File

@@ -2868,6 +2868,65 @@ C<method> must be one of C<gzip>, C<compress> or C<bzip2>.
See also: C<guestfs_file>");
("getxattrs", (RStructList ("xattrs", "xattr"), [String "path"]), 141, [],
[],
"list extended attributes of a file or directory",
"\
This call lists the extended attributes of the file or directory
C<path>.
At the system call level, this is a combination of the
L<listxattr(2)> and L<getxattr(2)> calls.
See also: C<guestfs_lgetxattrs>, L<attr(5)>.");
("lgetxattrs", (RStructList ("xattrs", "xattr"), [String "path"]), 142, [],
[],
"list extended attributes of a file or directory",
"\
This is the same as C<guestfs_getxattrs>, but if C<path>
is a symbolic link, then it returns the extended attributes
of the link itself.");
("setxattr", (RErr, [String "xattr";
String "val"; Int "vallen"; (* will be BufferIn *)
String "path"]), 143, [],
[],
"set extended attribute of a file or directory",
"\
This call sets the extended attribute named C<xattr>
of the file C<path> to the value C<val> (of length C<vallen>).
The value is arbitrary 8 bit data.
See also: C<guestfs_lsetxattr>, L<attr(5)>.");
("lsetxattr", (RErr, [String "xattr";
String "val"; Int "vallen"; (* will be BufferIn *)
String "path"]), 144, [],
[],
"set extended attribute of a file or directory",
"\
This is the same as C<guestfs_setxattr>, but if C<path>
is a symbolic link, then it sets an extended attribute
of the link itself.");
("removexattr", (RErr, [String "xattr"; String "path"]), 145, [],
[],
"remove extended attribute of a file or directory",
"\
This call removes the extended attribute named C<xattr>
of the file C<path>.
See also: C<guestfs_lremovexattr>, L<attr(5)>.");
("lremovexattr", (RErr, [String "xattr"; String "path"]), 146, [],
[],
"remove extended attribute of a file or directory",
"\
This is the same as C<guestfs_removexattr>, but if C<path>
is a symbolic link, then it removes an extended attribute
of the link itself.");
]
let all_functions = non_daemon_functions @ daemon_functions
@@ -2883,6 +2942,7 @@ let all_functions_sorted =
type field =
| FChar (* C 'char' (really, a 7 bit byte). *)
| FString (* nul-terminated ASCII string. *)
| FBuffer (* opaque buffer of bytes, (char *, int) pair *)
| FUInt32
| FInt32
| FUInt64
@@ -3021,6 +3081,12 @@ let structs = [
"release", FInt64;
"extra", FString;
];
(* Extended attribute. *)
"xattr", [
"attrname", FString;
"attrval", FBuffer;
];
] (* end of structs *)
(* Ugh, Java has to be different ..
@@ -3035,6 +3101,7 @@ let java_structs = [
"statvfs", "StatVFS";
"dirent", "Dirent";
"version", "Version";
"xattr", "XAttr";
]
(* Used for testing language bindings. *)
@@ -3448,6 +3515,10 @@ and generate_structs_pod () =
| name, (FUInt64|FBytes) -> pr " uint64_t %s;\n" name
| name, FInt64 -> pr " int64_t %s;\n" name
| name, FString -> pr " char *%s;\n" name
| name, FBuffer ->
pr " /* The next two fields describe a byte array. */\n";
pr " uint32_t %s_len;\n" name;
pr " char *%s;\n" name
| name, FUUID ->
pr " /* The next field is NOT nul-terminated, be careful when printing it: */\n";
pr " char %s[32];\n" name
@@ -3491,6 +3562,7 @@ and generate_xdr () =
List.iter (function
| name, FChar -> pr " char %s;\n" name
| name, FString -> pr " string %s<>;\n" name
| name, FBuffer -> pr " opaque %s<>;\n" name
| name, FUUID -> pr " opaque %s[32];\n" name
| name, (FInt32|FUInt32) -> pr " int %s;\n" name
| name, (FInt64|FUInt64|FBytes) -> pr " hyper %s;\n" name
@@ -3652,6 +3724,9 @@ and generate_structs_h () =
function
| name, FChar -> pr " char %s;\n" name
| name, FString -> pr " char *%s;\n" name
| name, FBuffer ->
pr " uint32_t %s_len;\n" name;
pr " char *%s;\n" name
| name, FUUID -> pr " char %s[32]; /* this is NOT nul-terminated, be careful when printing */\n" name
| name, FUInt32 -> pr " uint32_t %s;\n" name
| name, FInt32 -> pr " int32_t %s;\n" name
@@ -4269,7 +4344,7 @@ and generate_daemon_actions () =
pr " fprintf (stderr, \"%%s: failed to parse float '%%s' from token %%s\\n\", __func__, tok, \"%s\");\n" name;
pr " return -1;\n";
pr " }\n";
| FInt32 | FUInt32 | FUInt64 | FChar ->
| FBuffer | FInt32 | FUInt32 | FUInt64 | FChar ->
assert false (* can never be an LVM column *)
);
pr " tok = next;\n";
@@ -5052,6 +5127,7 @@ and generate_fish_cmds () =
pr "#include <stdlib.h>\n";
pr "#include <string.h>\n";
pr "#include <inttypes.h>\n";
pr "#include <ctype.h>\n";
pr "\n";
pr "#include <guestfs.h>\n";
pr "#include \"fish.h\"\n";
@@ -5129,7 +5205,7 @@ and generate_fish_cmds () =
List.iter (
fun (typ, cols) ->
let needs_i =
List.exists (function (_, FUUID) -> true | _ -> false) cols in
List.exists (function (_, (FUUID|FBuffer)) -> true | _ -> false) cols in
pr "static void print_%s (struct guestfs_%s *%s)\n" typ typ typ;
pr "{\n";
@@ -5146,6 +5222,14 @@ and generate_fish_cmds () =
pr " for (i = 0; i < 32; ++i)\n";
pr " printf (\"%%c\", %s->%s[i]);\n" typ name;
pr " printf (\"\\n\");\n"
| name, FBuffer ->
pr " printf (\"%s: \");\n" name;
pr " for (i = 0; i < %s->%s_len; ++i)\n" typ name;
pr " if (isprint (%s->%s[i]))\n" typ name;
pr " printf (\"%%c\", %s->%s[i]);\n" typ name;
pr " else\n";
pr " printf (\"\\\\x%%02x\", %s->%s[i]);\n" typ name;
pr " printf (\"\\n\");\n"
| name, (FUInt64|FBytes) ->
pr " printf (\"%s: %%\" PRIu64 \"\\n\", %s->%s);\n" name typ name
| name, FInt64 ->
@@ -5661,6 +5745,10 @@ copy_table (char * const * argv)
(match col with
| name, FString ->
pr " v = caml_copy_string (%s->%s);\n" typ name
| name, FBuffer ->
pr " v = caml_alloc_string (%s->%s_len);\n" typ name;
pr " memcpy (String_val (v), %s->%s, %s->%s_len);\n"
typ name typ name
| name, FUUID ->
pr " v = caml_alloc_string (32);\n";
pr " memcpy (String_val (v), %s->%s, 32);\n" typ name
@@ -5841,6 +5929,7 @@ and generate_ocaml_structure_decls () =
List.iter (
function
| name, FString -> pr " %s : string;\n" name
| name, FBuffer -> pr " %s : string;\n" name
| name, FUUID -> pr " %s : string;\n" name
| name, (FBytes|FInt64|FUInt64) -> pr " %s : int64;\n" name
| name, (FInt32|FUInt32) -> pr " %s : int32;\n" name
@@ -6137,6 +6226,9 @@ and generate_perl_struct_list_code typ cols name style n do_cleanups =
| name, FUUID ->
pr " (void) hv_store (hv, \"%s\", %d, newSVpv (%s->val[i].%s, 32), 0);\n"
name (String.length name) n name
| name, FBuffer ->
pr " (void) hv_store (hv, \"%s\", %d, newSVpv (%s->val[i].%s, %s->val[i].%s_len), 0);\n"
name (String.length name) n name n name
| name, (FBytes|FUInt64) ->
pr " (void) hv_store (hv, \"%s\", %d, my_newSVull (%s->val[i].%s), 0);\n"
name (String.length name) n name
@@ -6176,6 +6268,9 @@ and generate_perl_struct_code typ cols name style n do_cleanups =
| name, FString ->
pr " PUSHs (sv_2mortal (newSVpv (%s->%s, 0)));\n"
n name
| name, FBuffer ->
pr " PUSHs (sv_2mortal (newSVpv (%s->%s, %s->%s_len)));\n"
n name n name
| name, FUUID ->
pr " PUSHs (sv_2mortal (newSVpv (%s->%s, 32)));\n"
n name
@@ -6508,6 +6603,10 @@ py_guestfs_close (PyObject *self, PyObject *args)
pr " PyDict_SetItemString (dict, \"%s\",\n" name;
pr " PyString_FromString (%s->%s));\n"
typ name
| name, FBuffer ->
pr " PyDict_SetItemString (dict, \"%s\",\n" name;
pr " PyString_FromStringAndSize (%s->%s, %s->%s_len));\n"
typ name typ name
| name, FUUID ->
pr " PyDict_SetItemString (dict, \"%s\",\n" name;
pr " PyString_FromStringAndSize (%s->%s, 32));\n"
@@ -7051,6 +7150,8 @@ and generate_ruby_struct_code typ cols =
function
| name, FString ->
pr " rb_hash_aset (rv, rb_str_new2 (\"%s\"), rb_str_new2 (r->%s));\n" name name
| name, FBuffer ->
pr " rb_hash_aset (rv, rb_str_new2 (\"%s\"), rb_str_new (r->%s, r->%s_len));\n" name name name
| name, FUUID ->
pr " rb_hash_aset (rv, rb_str_new2 (\"%s\"), rb_str_new (r->%s, 32));\n" name name
| name, (FBytes|FUInt64) ->
@@ -7079,6 +7180,8 @@ and generate_ruby_struct_list_code typ cols =
function
| name, FString ->
pr " rb_hash_aset (hv, rb_str_new2 (\"%s\"), rb_str_new2 (r->val[i].%s));\n" name name
| name, FBuffer ->
pr " rb_hash_aset (hv, rb_str_new2 (\"%s\"), rb_str_new (r->val[i].%s, r->val[i].%s_len));\n" name name name
| name, FUUID ->
pr " rb_hash_aset (hv, rb_str_new2 (\"%s\"), rb_str_new (r->val[i].%s, 32));\n" name name
| name, (FBytes|FUInt64) ->
@@ -7290,7 +7393,8 @@ public class %s {
List.iter (
function
| name, FString
| name, FUUID -> pr " public String %s;\n" name
| name, FUUID
| name, FBuffer -> pr " public String %s;\n" name
| name, (FBytes|FUInt64|FInt64) -> pr " public long %s;\n" name
| name, (FUInt32|FInt32) -> pr " public int %s;\n" name
| name, FChar -> pr " public char %s;\n" name
@@ -7554,6 +7658,15 @@ and generate_java_struct_return typ jtyp cols =
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"Ljava/lang/String;\");\n" name;
pr " (*env)->SetObjectField (env, jr, fl, (*env)->NewStringUTF (env, s));\n";
pr " }\n";
| name, FBuffer ->
pr " {\n";
pr " int len = r->%s_len;\n" name;
pr " char s[len+1];\n";
pr " memcpy (s, r->%s, len);\n" name;
pr " s[len] = 0;\n";
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"Ljava/lang/String;\");\n" name;
pr " (*env)->SetObjectField (env, jr, fl, (*env)->NewStringUTF (env, s));\n";
pr " }\n";
| name, (FBytes|FUInt64|FInt64) ->
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"J\");\n" name;
pr " (*env)->SetLongField (env, jr, fl, r->%s);\n" name;
@@ -7588,6 +7701,15 @@ and generate_java_struct_list_return typ jtyp cols =
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"Ljava/lang/String;\");\n" name;
pr " (*env)->SetObjectField (env, jfl, fl, (*env)->NewStringUTF (env, s));\n";
pr " }\n";
| name, FBuffer ->
pr " {\n";
pr " int len = r->val[i].%s_len;\n" name;
pr " char s[len+1];\n";
pr " memcpy (s, r->val[i].%s, len);\n" name;
pr " s[len] = 0;\n";
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"Ljava/lang/String;\");\n" name;
pr " (*env)->SetObjectField (env, jfl, fl, (*env)->NewStringUTF (env, s));\n";
pr " }\n";
| name, (FBytes|FUInt64|FInt64) ->
pr " fl = (*env)->GetFieldID (env, cl, \"%s\", \"J\");\n" name;
pr " (*env)->SetLongField (env, jfl, fl, r->val[i].%s);\n" name;