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/*
* Wrapper functions for <sys/xattr.h> (or <attr/xattr.h>) and <sys/extattr.h>
*
* Authors:
* Daniel Drake (dsd@gentoo.org)
* Jonathan Pryor (jonpryor@vt.edu)
*
* Copyright (C) 2005 Daniel Drake
* Copyright (C) 2006 Jonathan Pryor
*/
#include <config.h>
//If we're compiling to API level < 16 this won't be available
#if __ANDROID_API__ < 16
#define ANDROID_NO_XATTR
#endif
#if (defined(HAVE_SYS_XATTR_H) || defined(HAVE_ATTR_ATTR_H) || defined(HAVE_SYS_EXTATTR_H)) && !defined (ANDROID_NO_XATTR)
#include <sys/types.h>
/*
* Where available, we prefer to use the libc implementation of the xattr
* syscalls. However, we also support using libattr for this on systems where
* libc does not provide this (e.g. glibc-2.2 and older)
* (configure-time magic is used to select which library to link to)
*/
#ifdef HAVE_SYS_XATTR_H
// libc
#include <sys/xattr.h>
#define EA_UNIX
#elif HAVE_ATTR_ATTR_H
// libattr
#include <attr/xattr.h>
#define EA_UNIX
#endif /* HAVE_SYS_XATTR_H */
#ifdef HAVE_SYS_EXTATTR_H
#include <sys/extattr.h>
#include <sys/uio.h>
#define EA_BSD
#endif
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include "map.h"
#include "mph.h"
/*
* Linux provides extended attributes through the <sys/xattr.h> API.
* Any file or link can have attributes assigned to it (provided that they are
* supported by the backing filesystem). Each attribute has to be placed in a
* namespace, of which "user" is the most common. Namespaces are specified as
* a prefix to the attribute name, proceeded by a '.' (e.g. user.myattribute)
*
* FreeBSD provides extended attributes through the <sys/extattr.h> API.
* Behaviour is very similar to Linux EA's, but the namespace is specified
* through an enum-style parameter rather than as a prefix to an attribute
* name. There are also differences in the behaviour of the "list attributes"
* system calls.
*
* This file merges the two implementations into a single API for use by the
* Mono.Unix.Syscall.*xattr methods. No matter which OS you are on, things
* should "just work" the same as anywhere else.
*
* The API provided here leans more towards the Linux implementation. Attribute
* namespaces are provided as prefixes to the attribute name (followed by '.').
* There is no limit to the namespaces accepted by the Linux side of this
* implementation, but you are obviously limited to the ones available to you
* on the system.
* FreeBSD namespaces have to be converted from the textual prefix into their
* relevant number so that they can be used in the FreeBSD system calls.
* This means that the only namespaces available are the ones known by in this
* file (see bsd_extattr_namespaces). However, you can also specify the
* numericalnamespace index yourself, by using an attribute name such as
* "5.myattr".
* (this will obviously fail on Linux, your code will no longer be 'portable')
*
* Linux {,l,f}setxattr calls have a flags parameter which allow you to control
* what should happen if an attribute with the same name does (or doesn't)
* already exist. The 'flags' parameter is available here, but because FreeBSD
* does not support this kind of refinement, it will fail on FreeBSD if you
* specify anything other than XATTR_AUTO (XATTR_AUTO will create the attribute
* if it doesn't already exist, and overwrite the existing attribute if it
* already set).
*
* For usage and behaviour information, see the monodoc documentation on the
* Mono.Unix.Syscall class.
*/
G_BEGIN_DECLS
//
// HELPER FUNCTIONS
//
#ifdef EA_BSD
struct BsdNamespaceInfo {
const char *name;
int value;
};
static struct BsdNamespaceInfo bsd_extattr_namespaces[] = {
{"user" , EXTATTR_NAMESPACE_USER},
{"system" , EXTATTR_NAMESPACE_SYSTEM}
};
static int bsd_check_flags (gint32 flags)
{
// BSD doesn't support flags, but always provides the same behaviour as
// XATTR_AUTO. So we enforce that here.
if (flags != Mono_Posix_XattrFlags_XATTR_AUTO) {
errno = EINVAL;
return -1;
}
return 0;
}
// On FreeBSD, we need to convert "user.blah" into namespace 1 and attribute
// name "blah", or maybe "6.blah" into namespace 6 attribute "blah"
static int
bsd_handle_nsprefix (const char *name, char **_name, int *namespace)
{
int i;
gchar **components = g_strsplit (name, ".", 2);
// Find namespace number from textual representation
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++)
if (strcmp (bsd_extattr_namespaces[i].name, components[0]) == 0) {
*namespace = bsd_extattr_namespaces[i].value;
break;
}
if (*namespace == 0) {
// Perhaps they specified the namespace number themselves..?
char *endptr;
*namespace = (int) strtol (components[0], &endptr, 10);
if (*endptr != '\0')
return -1;
}
*_name = g_strdup (components[1]);
g_strfreev (components);
return 0;
}
static void
init_attrlists (char *attrlists[])
{
memset (attrlists, 0, G_N_ELEMENTS(bsd_extattr_namespaces) * sizeof(char*));
}
static void
free_attrlists (char *attrlists[])
{
int i;
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++)
g_free (attrlists[i]);
}
// Counts the number of attributes in the result of a
// extattr_list_*() call. Note that the format of the data
// is: \3one\3two\6eleven where the leading charaters represent the length
// of the following attribute. (the description in the man-page is wrong)
static unsigned int
count_num_attrs (char *attrs, size_t size)
{
size_t i = 0;
unsigned int num_attrs = 0;
if (!attrs || !size)
return 0;
while (i < size) {
num_attrs++;
i += attrs[i] + 1;
}
return num_attrs;
}
// Convert a BSD-style list buffer (see the description for count_num_attrs)
// into a Linux-style NULL-terminated list including namespace prefix.
static char
*bsd_convert_list (const char *nsprefix, const char *src, size_t size, char *dest)
{
size_t i = 0;
if (src == NULL || dest == NULL || size == 0)
return NULL;
while (i < size) {
// Read length
int attr_len = (int) src[i];
int prefix_len = strlen (nsprefix);
// Add namespace prefix
strncpy (dest, nsprefix, prefix_len);
dest[prefix_len] = '.';
dest += prefix_len + 1;
// Copy attribute
memcpy(dest, src + ++i, attr_len);
// NULL-terminate
i += attr_len;
dest[attr_len] = '\0';
dest += attr_len + 1;
}
return dest;
}
// Combine all the lists of attributes that we know about into a single
// Linux-style buffer
static ssize_t
bsd_combine_lists (char *attrlists[], char *dest, size_t dest_size_needed, size_t dest_size)
{
int i;
if (!dest)
return dest_size_needed;
if (dest_size < dest_size_needed) {
errno = ERANGE;
return -1;
}
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++)
if (attrlists[i])
dest = bsd_convert_list (bsd_extattr_namespaces[i].name, attrlists[i], strlen (attrlists[i]), dest);
return dest_size_needed;
}
static mph_ssize_t
bsd_listxattr (const char *path, void *list, mph_size_t size)
{
size_t full_size = 0;
int i;
char *attrlists[G_N_ELEMENTS(bsd_extattr_namespaces)];
init_attrlists (attrlists);
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++) {
size_t buf_size;
int num_attrs;
buf_size = (size_t) extattr_list_file (path, i + 1, NULL, 0);
if (buf_size == -1)
continue;
attrlists[i] = g_malloc0 (buf_size + 1);
buf_size = (size_t) extattr_list_file (path, i + 1, attrlists[i], buf_size);
if (buf_size == -1)
continue;
num_attrs = count_num_attrs(attrlists[i], buf_size);
full_size += buf_size + (num_attrs * (strlen (bsd_extattr_namespaces[i].name) + 1));
}
full_size = bsd_combine_lists (attrlists, (char *) list, full_size, size);
free_attrlists (attrlists);
return full_size;
}
static mph_ssize_t
bsd_llistxattr (const char *path, void *list, mph_size_t size)
{
size_t full_size = 0;
int i;
char *attrlists[G_N_ELEMENTS(bsd_extattr_namespaces)];
init_attrlists (attrlists);
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++) {
size_t buf_size;
int num_attrs;
buf_size = (size_t) extattr_list_link (path, i + 1, NULL, 0);
if (buf_size == -1)
continue;
attrlists[i] = g_malloc0 (buf_size + 1);
buf_size = (size_t) extattr_list_link (path, i + 1, attrlists[i], buf_size);
if (buf_size == -1)
continue;
num_attrs = count_num_attrs(attrlists[i], buf_size);
full_size += buf_size + (num_attrs * (strlen (bsd_extattr_namespaces[i].name) + 1));
}
full_size = bsd_combine_lists (attrlists, (char *) list, full_size, size);
free_attrlists (attrlists);
return full_size;
}
static mph_ssize_t
bsd_flistxattr (int fd, void *list, mph_size_t size)
{
size_t full_size = 0;
int i;
char *attrlists[G_N_ELEMENTS(bsd_extattr_namespaces)];
init_attrlists (attrlists);
for (i = 0; i < G_N_ELEMENTS(bsd_extattr_namespaces); i++) {
size_t buf_size;
int num_attrs;
buf_size = (size_t) extattr_list_fd (fd, i + 1, NULL, 0);
if (buf_size == -1)
continue;
attrlists[i] = g_malloc0 (buf_size + 1);
buf_size = (size_t) extattr_list_fd (fd, i + 1, attrlists[i], buf_size);
if (buf_size == -1)
continue;
num_attrs = count_num_attrs(attrlists[i], buf_size);
full_size += buf_size + (num_attrs * (strlen (bsd_extattr_namespaces[i].name) + 1));
}
full_size = bsd_combine_lists (attrlists, (char *) list, full_size, size);
free_attrlists (attrlists);
return full_size;
}
#endif /* EA_BSD */
//
// THE PROVIDED API
//
gint32
Mono_Posix_Syscall_setxattr (const char *path, const char *name, unsigned char *value, mph_size_t size, gint32 flags)
{
gint32 ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
{
int _flags;
if (Mono_Posix_FromXattrFlags (flags, &_flags) == -1)
return -1;
#if __APPLE__
ret = setxattr (path, name, value, (size_t) size, 0, _flags);
#else /* __APPLE__ */
ret = setxattr (path, name, value, (size_t) size, _flags);
#endif /* __APPLE__ */
}
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_check_flags (flags) == -1)
return -1;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_set_file (path, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#if !__APPLE__
gint32
Mono_Posix_Syscall_lsetxattr (const char *path, const char *name, unsigned char *value, mph_size_t size, gint32 flags)
{
gint32 ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
{
int _flags;
if (Mono_Posix_FromXattrFlags (flags, &_flags) == -1)
return -1;
ret = lsetxattr (path, name, value, size, _flags);
}
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_check_flags (flags) == -1)
return -1;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_set_link (path, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#endif /* !__APPLE__ */
gint32
Mono_Posix_Syscall_fsetxattr (int fd, const char *name, unsigned char *value, mph_size_t size, gint32 flags)
{
gint32 ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
{
int _flags;
if (Mono_Posix_FromXattrFlags (flags, &_flags) == -1)
return -1;
#if __APPLE__
ret = fsetxattr (fd, name, value, (size_t) size, 0, _flags);
#else /* __APPLE__ */
ret = fsetxattr (fd, name, value, (size_t) size, _flags);
#endif /* __APPLE__ */
}
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_check_flags (flags) == -1)
return -1;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_set_fd (fd, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
mph_ssize_t
Mono_Posix_Syscall_getxattr (const char *path, const char *name, unsigned char *value, mph_size_t size)
{
mph_ssize_t ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
#if __APPLE__
ret = getxattr (path, name, value, (size_t) size, 0, 0);
#else /* __APPLE__ */
ret = getxattr (path, name, value, (size_t) size);
#endif /* __APPLE__ */
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_get_file (path, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#if !__APPLE__
mph_ssize_t
Mono_Posix_Syscall_lgetxattr (const char *path, const char *name, unsigned char *value, mph_size_t size)
{
mph_ssize_t ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
ret = lgetxattr (path, name, value, (size_t) size);
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_get_link (path, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#endif /* !__APPLE__ */
mph_ssize_t
Mono_Posix_Syscall_fgetxattr (int fd, const char *name, unsigned char *value, mph_size_t size)
{
mph_ssize_t ret;
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
#if __APPLE__
ret = fgetxattr (fd, name, value, (size_t) size, 0, 0);
#else /* __APPLE__ */
ret = fgetxattr (fd, name, value, (size_t) size);
#endif /* __APPLE__ */
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_get_fd (fd, namespace, _name, value, (size_t) size);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
mph_ssize_t
Mono_Posix_Syscall_listxattr (const char *path, unsigned char *list, mph_size_t size)
{
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
#if __APPLE__
return listxattr (path, (char*) list, (size_t) size, 0);
#else /* __APPLE__ */
return listxattr (path, (char*) list, (size_t) size);
#endif /* __APPLE__ */
#else /* EA_UNIX */
return bsd_listxattr (path, list, size);
#endif /* EA_UNIX */
}
#if !__APPLE__
mph_ssize_t
Mono_Posix_Syscall_llistxattr (const char *path, unsigned char *list, mph_size_t size)
{
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
return llistxattr (path, (char*) list, (size_t) size);
#else /* EA_UNIX */
return bsd_llistxattr (path, list, size);
#endif /* EA_UNIX */
}
#endif /* !__APPLE__ */
mph_ssize_t
Mono_Posix_Syscall_flistxattr (int fd, unsigned char *list, mph_size_t size)
{
mph_return_if_size_t_overflow (size);
#ifdef EA_UNIX
#if __APPLE__
return flistxattr (fd, (char*) list, (size_t) size, 0);
#else /* __APPLE__ */
return flistxattr (fd, (char*) list, (size_t) size);
#endif /* __APPLE__ */
#else /* EA_UNIX */
return bsd_flistxattr (fd, list, size);
#endif /* EA_UNIX */
}
gint32
Mono_Posix_Syscall_removexattr (const char *path, const char *name)
{
gint32 ret;
#ifdef EA_UNIX
#if __APPLE__
ret = removexattr (path, name, 0);
#else /* __APPLE__ */
ret = removexattr (path, name);
#endif /* __APPLE__ */
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_delete_file (path, namespace, _name);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#if !__APPLE__
gint32
Mono_Posix_Syscall_lremovexattr (const char *path, const char *name)
{
gint32 ret;
#ifdef EA_UNIX
ret = lremovexattr (path, name);
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_delete_link (path, namespace, _name);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
#endif /* !__APPLE__ */
gint32
Mono_Posix_Syscall_fremovexattr (int fd, const char *name)
{
gint32 ret;
#ifdef EA_UNIX
#if __APPLE__
ret = fremovexattr (fd, name, 0);
#else /* __APPLE__ */
ret = fremovexattr (fd, name);
#endif /* __APPLE__ */
#else /* EA_UNIX */
{
char *_name;
int namespace;
if (bsd_handle_nsprefix (name, &_name, &namespace) == -1)
return -1;
ret = extattr_delete_fd (fd, namespace, _name);
g_free (_name);
}
#endif /* EA_UNIX */
return ret;
}
G_END_DECLS
#endif /* HAVE_SYS_XATTR_H || HAVE_ATTR_ATTR_H || HAVE_SYS_EXTATTR_H */
/*
* vim: noexpandtab
*/