genode/repos/os/include/vfs/directory_service.h

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/*
* \brief Directory-service interface
* \author Norman Feske
* \date 2011-02-17
*/
/*
* Copyright (C) 2011-2017 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU Affero General Public License version 3.
*/
#ifndef _INCLUDE__VFS__DIRECTORY_SERVICE_H_
#define _INCLUDE__VFS__DIRECTORY_SERVICE_H_
#include <vfs/types.h>
namespace Vfs {
class Vfs_handle;
class Vfs_watch_handle;
struct Directory_service;
using Genode::Allocator;
}
Follow practices suggested by "Effective C++" The patch adjust the code of the base, base-<kernel>, and os repository. To adapt existing components to fix violations of the best practices suggested by "Effective C++" as reported by the -Weffc++ compiler argument. The changes follow the patterns outlined below: * A class with virtual functions can no longer publicly inherit base classed without a vtable. The inherited object may either be moved to a member variable, or inherited privately. The latter would be used for classes that inherit 'List::Element' or 'Avl_node'. In order to enable the 'List' and 'Avl_tree' to access the meta data, the 'List' must become a friend. * Instead of adding a virtual destructor to abstract base classes, we inherit the new 'Interface' class, which contains a virtual destructor. This way, single-line abstract base classes can stay as compact as they are now. The 'Interface' utility resides in base/include/util/interface.h. * With the new warnings enabled, all member variables must be explicitly initialized. Basic types may be initialized with '='. All other types are initialized with braces '{ ... }' or as class initializers. If basic types and non-basic types appear in a row, it is nice to only use the brace syntax (also for basic types) and align the braces. * If a class contains pointers as members, it must now also provide a copy constructor and assignment operator. In the most cases, one would make them private, effectively disallowing the objects to be copied. Unfortunately, this warning cannot be fixed be inheriting our existing 'Noncopyable' class (the compiler fails to detect that the inheriting class cannot be copied and still gives the error). For now, we have to manually add declarations for both the copy constructor and assignment operator as private class members. Those declarations should be prepended with a comment like this: /* * Noncopyable */ Thread(Thread const &); Thread &operator = (Thread const &); In the future, we should revisit these places and try to replace the pointers with references. In the presence of at least one reference member, the compiler would no longer implicitly generate a copy constructor. So we could remove the manual declaration. Issue #465
2017-12-21 14:42:15 +00:00
struct Vfs::Directory_service : Interface
{
virtual Dataspace_capability dataspace(char const *path) = 0;
virtual void release(char const *path, Dataspace_capability) = 0;
enum General_error { ERR_FD_INVALID, NUM_GENERAL_ERRORS };
/**********
** Open **
**********/
/**
* Flags of 'mode' argument of open syscall
*/
enum {
OPEN_MODE_RDONLY = 0,
OPEN_MODE_WRONLY = 1,
OPEN_MODE_RDWR = 2,
OPEN_MODE_ACCMODE = 3,
OPEN_MODE_CREATE = 0x0800, /* libc O_EXCL */
};
enum Open_result
{
OPEN_ERR_UNACCESSIBLE,
OPEN_ERR_NO_PERM,
OPEN_ERR_EXISTS,
OPEN_ERR_NAME_TOO_LONG,
OPEN_ERR_NO_SPACE,
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
OPEN_ERR_OUT_OF_RAM,
OPEN_ERR_OUT_OF_CAPS,
OPEN_OK
};
virtual Open_result open(char const *path,
unsigned mode,
Vfs_handle **handle,
Allocator &alloc) = 0;
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
enum Opendir_result
{
OPENDIR_ERR_LOOKUP_FAILED,
OPENDIR_ERR_NAME_TOO_LONG,
OPENDIR_ERR_NODE_ALREADY_EXISTS,
OPENDIR_ERR_NO_SPACE,
OPENDIR_ERR_OUT_OF_RAM,
OPENDIR_ERR_OUT_OF_CAPS,
OPENDIR_ERR_PERMISSION_DENIED,
OPENDIR_OK
};
Follow practices suggested by "Effective C++" The patch adjust the code of the base, base-<kernel>, and os repository. To adapt existing components to fix violations of the best practices suggested by "Effective C++" as reported by the -Weffc++ compiler argument. The changes follow the patterns outlined below: * A class with virtual functions can no longer publicly inherit base classed without a vtable. The inherited object may either be moved to a member variable, or inherited privately. The latter would be used for classes that inherit 'List::Element' or 'Avl_node'. In order to enable the 'List' and 'Avl_tree' to access the meta data, the 'List' must become a friend. * Instead of adding a virtual destructor to abstract base classes, we inherit the new 'Interface' class, which contains a virtual destructor. This way, single-line abstract base classes can stay as compact as they are now. The 'Interface' utility resides in base/include/util/interface.h. * With the new warnings enabled, all member variables must be explicitly initialized. Basic types may be initialized with '='. All other types are initialized with braces '{ ... }' or as class initializers. If basic types and non-basic types appear in a row, it is nice to only use the brace syntax (also for basic types) and align the braces. * If a class contains pointers as members, it must now also provide a copy constructor and assignment operator. In the most cases, one would make them private, effectively disallowing the objects to be copied. Unfortunately, this warning cannot be fixed be inheriting our existing 'Noncopyable' class (the compiler fails to detect that the inheriting class cannot be copied and still gives the error). For now, we have to manually add declarations for both the copy constructor and assignment operator as private class members. Those declarations should be prepended with a comment like this: /* * Noncopyable */ Thread(Thread const &); Thread &operator = (Thread const &); In the future, we should revisit these places and try to replace the pointers with references. In the presence of at least one reference member, the compiler would no longer implicitly generate a copy constructor. So we could remove the manual declaration. Issue #465
2017-12-21 14:42:15 +00:00
virtual Opendir_result opendir(char const * /* path */, bool /* create */,
Vfs_handle **, Allocator &)
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
{
return OPENDIR_ERR_LOOKUP_FAILED;
}
enum Openlink_result
{
OPENLINK_ERR_LOOKUP_FAILED,
OPENLINK_ERR_NAME_TOO_LONG,
OPENLINK_ERR_NODE_ALREADY_EXISTS,
OPENLINK_ERR_NO_SPACE,
OPENLINK_ERR_OUT_OF_RAM,
OPENLINK_ERR_OUT_OF_CAPS,
OPENLINK_ERR_PERMISSION_DENIED,
OPENLINK_OK
};
Follow practices suggested by "Effective C++" The patch adjust the code of the base, base-<kernel>, and os repository. To adapt existing components to fix violations of the best practices suggested by "Effective C++" as reported by the -Weffc++ compiler argument. The changes follow the patterns outlined below: * A class with virtual functions can no longer publicly inherit base classed without a vtable. The inherited object may either be moved to a member variable, or inherited privately. The latter would be used for classes that inherit 'List::Element' or 'Avl_node'. In order to enable the 'List' and 'Avl_tree' to access the meta data, the 'List' must become a friend. * Instead of adding a virtual destructor to abstract base classes, we inherit the new 'Interface' class, which contains a virtual destructor. This way, single-line abstract base classes can stay as compact as they are now. The 'Interface' utility resides in base/include/util/interface.h. * With the new warnings enabled, all member variables must be explicitly initialized. Basic types may be initialized with '='. All other types are initialized with braces '{ ... }' or as class initializers. If basic types and non-basic types appear in a row, it is nice to only use the brace syntax (also for basic types) and align the braces. * If a class contains pointers as members, it must now also provide a copy constructor and assignment operator. In the most cases, one would make them private, effectively disallowing the objects to be copied. Unfortunately, this warning cannot be fixed be inheriting our existing 'Noncopyable' class (the compiler fails to detect that the inheriting class cannot be copied and still gives the error). For now, we have to manually add declarations for both the copy constructor and assignment operator as private class members. Those declarations should be prepended with a comment like this: /* * Noncopyable */ Thread(Thread const &); Thread &operator = (Thread const &); In the future, we should revisit these places and try to replace the pointers with references. In the presence of at least one reference member, the compiler would no longer implicitly generate a copy constructor. So we could remove the manual declaration. Issue #465
2017-12-21 14:42:15 +00:00
virtual Openlink_result openlink(char const * /* path */, bool /* create */,
Vfs_handle **, Allocator &)
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
{
return OPENLINK_ERR_PERMISSION_DENIED;
}
/**
* Close handle resources and deallocate handle
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
*
* Note: it might be necessary to call 'sync()' before 'close()'
* to ensure that previously written data has been completely
* processed.
*/
virtual void close(Vfs_handle *handle) = 0;
enum Watch_result
{
WATCH_ERR_UNACCESSIBLE,
WATCH_ERR_STATIC,
WATCH_ERR_OUT_OF_RAM,
WATCH_ERR_OUT_OF_CAPS,
WATCH_OK
};
/**
* Watch a file-system node for changes.
*/
virtual Watch_result watch(char const *path,
Vfs_watch_handle**,
Allocator&)
{
/* default implementation for static file-systems */
return (leaf_path(path)) ? WATCH_ERR_STATIC : WATCH_ERR_UNACCESSIBLE;
}
virtual void close(Vfs_watch_handle *)
{
Genode::error("watch handle closed at invalid file-system");
throw ~0;
};
/**********
** Stat **
**********/
/**
* These values are the same as in the FreeBSD libc
*/
enum {
STAT_MODE_SYMLINK = 0120000,
STAT_MODE_FILE = 0100000,
STAT_MODE_DIRECTORY = 0040000,
STAT_MODE_CHARDEV = 0020000,
STAT_MODE_BLOCKDEV = 0060000,
};
struct Stat
{
file_size size = 0;
unsigned mode = 0;
unsigned uid = 0;
unsigned gid = 0;
unsigned long inode = 0;
unsigned long device = 0;
Timestamp modification_time { Timestamp::INVALID };
};
enum Stat_result { STAT_ERR_NO_ENTRY = NUM_GENERAL_ERRORS,
STAT_ERR_NO_PERM, STAT_OK };
VFS: nonblocking interface The VFS library can be used in single-threaded or multi-threaded environments and depending on that, signals are handled by the same thread which uses the VFS library or possibly by a different thread. If a VFS plugin needs to block to wait for a signal, there is currently no way which works reliably in both environments. For this reason, this commit makes the interface of the VFS library nonblocking, similar to the File_system session interface. The most important changes are: - Directories are created and opened with the 'opendir()' function and the directory entries are read with the recently introduced 'queue_read()' and 'complete_read()' functions. - Symbolic links are created and opened with the 'openlink()' function and the link target is read with the 'queue_read()' and 'complete_read()' functions and written with the 'write()' function. - The 'write()' function does not wait for signals anymore. This can have the effect that data written by a VFS library user has not been processed by a file system server yet when the library user asks for the size of the file or closes it (both done with RPC functions at the file system server). For this reason, a user of the VFS library should request synchronization before calling 'stat()' or 'close()'. To make sure that a file system server has processed all write request packets which a client submitted before the synchronization request, synchronization is now requested at the file system server with a synchronization packet instead of an RPC function. Because of this change, the synchronization interface of the VFS library is now split into 'queue_sync()' and 'complete_sync()' functions. Fixes #2399
2017-08-15 18:51:53 +00:00
/*
* Note: it might be necessary to call 'sync()' before 'stat()'
* to get the correct file size.
*/
virtual Stat_result stat(char const *path, Stat &) = 0;
/************
** Dirent **
************/
enum { DIRENT_MAX_NAME_LEN = 128 };
enum Dirent_type {
DIRENT_TYPE_FILE,
DIRENT_TYPE_DIRECTORY,
DIRENT_TYPE_FIFO,
DIRENT_TYPE_CHARDEV,
DIRENT_TYPE_BLOCKDEV,
DIRENT_TYPE_SYMLINK,
DIRENT_TYPE_END
};
struct Dirent
{
unsigned long fileno = 0;
Dirent_type type = DIRENT_TYPE_END;
char name[DIRENT_MAX_NAME_LEN] = { 0 };
};
/************
** Unlink **
************/
enum Unlink_result { UNLINK_ERR_NO_ENTRY, UNLINK_ERR_NO_PERM,
UNLINK_ERR_NOT_EMPTY, UNLINK_OK };
virtual Unlink_result unlink(char const *path) = 0;
/************
** Rename **
************/
enum Rename_result { RENAME_ERR_NO_ENTRY, RENAME_ERR_CROSS_FS,
RENAME_ERR_NO_PERM, RENAME_OK };
virtual Rename_result rename(char const *from, char const *to) = 0;
/**
* Return number of directory entries located at given path
*/
virtual file_size num_dirent(char const *path) = 0;
virtual bool directory(char const *path) = 0;
/**
* Return leaf path or nullptr if the path does not exist
*/
virtual char const *leaf_path(char const *path) = 0;
};
#endif /* _INCLUDE__VFS__DIRECTORY_SERVICE_H_ */