From 510064b14e8fddafe615f8c707023fcc3f84f094 Mon Sep 17 00:00:00 2001 From: Gerald Carter Date: Fri, 10 Oct 2003 16:21:39 +0000 Subject: removing docs from HEAD (This used to be commit 820903ef5a062b4b9824c33ee035c68a39c8eeb0) --- docs/docbook/devdoc/vfs.xml | 797 -------------------------------------------- 1 file changed, 797 deletions(-) delete mode 100644 docs/docbook/devdoc/vfs.xml (limited to 'docs/docbook/devdoc/vfs.xml') diff --git a/docs/docbook/devdoc/vfs.xml b/docs/docbook/devdoc/vfs.xml deleted file mode 100644 index ed2afef53e..0000000000 --- a/docs/docbook/devdoc/vfs.xml +++ /dev/null @@ -1,797 +0,0 @@ - - - - AlexanderBokovoy - -
ab@samba.org
- - - - StefanMetzmacher - -
metze@metzemix.de
- - - 27 May 2003 - - -VFS Modules - - -The Samba (Posix) VFS layer - - -The general interface - - -Each VFS operation has a vfs_op_type, a function pointer and a handle pointer in the -struct vfs_ops and tree macros to make it easier to call the operations. -(Take a look at include/vfs.h and include/vfs_macros.h.) - - - -typedef enum _vfs_op_type { - SMB_VFS_OP_NOOP = -1, - - ... - - /* File operations */ - - SMB_VFS_OP_OPEN, - SMB_VFS_OP_CLOSE, - SMB_VFS_OP_READ, - SMB_VFS_OP_WRITE, - SMB_VFS_OP_LSEEK, - SMB_VFS_OP_SENDFILE, - - ... - - SMB_VFS_OP_LAST -} vfs_op_type; - - -This struct contains the function and handle pointers for all operations. -struct vfs_ops { - struct vfs_fn_pointers { - ... - - /* File operations */ - - int (*open)(struct vfs_handle_struct *handle, - struct connection_struct *conn, - const char *fname, int flags, mode_t mode); - int (*close)(struct vfs_handle_struct *handle, - struct files_struct *fsp, int fd); - ssize_t (*read)(struct vfs_handle_struct *handle, - struct files_struct *fsp, int fd, void *data, size_t n); - ssize_t (*write)(struct vfs_handle_struct *handle, - struct files_struct *fsp, int fd, - const void *data, size_t n); - SMB_OFF_T (*lseek)(struct vfs_handle_struct *handle, - struct files_struct *fsp, int fd, - SMB_OFF_T offset, int whence); - ssize_t (*sendfile)(struct vfs_handle_struct *handle, - int tofd, files_struct *fsp, int fromfd, - const DATA_BLOB *header, SMB_OFF_T offset, size_t count); - - ... - } ops; - - struct vfs_handles_pointers { - ... - - /* File operations */ - - struct vfs_handle_struct *open; - struct vfs_handle_struct *close; - struct vfs_handle_struct *read; - struct vfs_handle_struct *write; - struct vfs_handle_struct *lseek; - struct vfs_handle_struct *sendfile; - - ... - } handles; -}; - - - -This macros SHOULD be used to call any vfs operation. -DO NOT ACCESS conn->vfs.ops.* directly !!! - -... - -/* File operations */ -#define SMB_VFS_OPEN(conn, fname, flags, mode) \ - ((conn)->vfs.ops.open((conn)->vfs.handles.open,\ - (conn), (fname), (flags), (mode))) -#define SMB_VFS_CLOSE(fsp, fd) \ - ((fsp)->conn->vfs.ops.close(\ - (fsp)->conn->vfs.handles.close, (fsp), (fd))) -#define SMB_VFS_READ(fsp, fd, data, n) \ - ((fsp)->conn->vfs.ops.read(\ - (fsp)->conn->vfs.handles.read,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_WRITE(fsp, fd, data, n) \ - ((fsp)->conn->vfs.ops.write(\ - (fsp)->conn->vfs.handles.write,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_LSEEK(fsp, fd, offset, whence) \ - ((fsp)->conn->vfs.ops.lseek(\ - (fsp)->conn->vfs.handles.lseek,\ - (fsp), (fd), (offset), (whence))) -#define SMB_VFS_SENDFILE(tofd, fsp, fromfd, header, offset, count) \ - ((fsp)->conn->vfs.ops.sendfile(\ - (fsp)->conn->vfs.handles.sendfile,\ - (tofd), (fsp), (fromfd), (header), (offset), (count))) - -... - - - - - -Possible VFS operation layers - - -These values are used by the VFS subsystem when building the conn->vfs -and conn->vfs_opaque structs for a connection with multiple VFS modules. -Internally, Samba differentiates only opaque and transparent layers at this process. -Other types are used for providing better diagnosing facilities. - - - -Most modules will provide transparent layers. Opaque layer is for modules -which implement actual file system calls (like DB-based VFS). For example, -default POSIX VFS which is built in into Samba is an opaque VFS module. - - - -Other layer types (logger, splitter, scanner) were designed to provide different -degree of transparency and for diagnosing VFS module behaviour. - - - -Each module can implement several layers at the same time provided that only -one layer is used per each operation. - - - -typedef enum _vfs_op_layer { - SMB_VFS_LAYER_NOOP = -1, /* - For using in VFS module to indicate end of array */ - /* of operations description */ - SMB_VFS_LAYER_OPAQUE = 0, /* - Final level, does not call anything beyond itself */ - SMB_VFS_LAYER_TRANSPARENT, /* - Normal operation, calls underlying layer after */ - /* possibly changing passed data */ - SMB_VFS_LAYER_LOGGER, /* - Logs data, calls underlying layer, logging may not */ - /* use Samba VFS */ - SMB_VFS_LAYER_SPLITTER, /* - Splits operation, calls underlying layer _and_ own facility, */ - /* then combines result */ - SMB_VFS_LAYER_SCANNER /* - Checks data and possibly initiates additional */ - /* file activity like logging to files _inside_ samba VFS */ -} vfs_op_layer; - - - - - - - -The Interaction between the Samba VFS subsystem and the modules - - -Initialization and registration - - -As each Samba module a VFS module should have a -NTSTATUS vfs_example_init(void); function if it's staticly linked to samba or -NTSTATUS init_module(void); function if it's a shared module. - - - -This should be the only non static function inside the module. -Global variables should also be static! - - - -The module should register its functions via the - -NTSTATUS smb_register_vfs(int version, const char *name, vfs_op_tuple *vfs_op_tuples); - function. - - - - -version -should be filled with SMB_VFS_INTERFACE_VERSION - - -name -this is the name witch can be listed in the -vfs objects parameter to use this module. - - -vfs_op_tuples - -this is an array of vfs_op_tuple's. -(vfs_op_tuples is descripted in details below.) - - - - - - -For each operation the module wants to provide it has a entry in the -vfs_op_tuple array. - - - -typedef struct _vfs_op_tuple { - void* op; - vfs_op_type type; - vfs_op_layer layer; -} vfs_op_tuple; - - - - -op -the function pointer to the specified function. - - -type -the vfs_op_type of the function to specified witch operation the function provides. - - -layer -the vfs_op_layer in whitch the function operates. - - - - -A simple example: - - -static vfs_op_tuple example_op_tuples[] = { - {SMB_VFS_OP(example_connect), SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT}, - {SMB_VFS_OP(example_disconnect), SMB_VFS_OP_DISCONNECT, SMB_VFS_LAYER_TRANSPARENT}, - - {SMB_VFS_OP(example_rename), SMB_VFS_OP_RENAME, SMB_VFS_LAYER_OPAQUE}, - - /* This indicates the end of the array */ - {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP} -}; - -NTSTATUS init_module(void) -{ - return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "example", example_op_tuples); -} - - - - - -How the Modules handle per connection data - -Each VFS function has as first parameter a pointer to the modules vfs_handle_struct. - - - -typedef struct vfs_handle_struct { - struct vfs_handle_struct *next, *prev; - const char *param; - struct vfs_ops vfs_next; - struct connection_struct *conn; - void *data; - void (*free_data)(void **data); -} vfs_handle_struct; - - - - -param -this is the module parameter specified in the vfs objects parameter. -e.g. for 'vfs objects = example:test' param would be "test". - - -vfs_next -This vfs_ops struct contains the information for calling the next module operations. -Use the SMB_VFS_NEXT_* macros to call a next module operations and -don't access handle->vfs_next.ops.* directly! - - -conn -This is a pointer back to the connection_struct to witch the handle belongs. - - -data -This is a pointer for holding module private data. -You can alloc data with connection life time on the handle->conn->mem_ctx TALLOC_CTX. -But you can also manage the memory allocation yourself. - - -free_data -This is a function pointer to a function that free's the module private data. -If you talloc your private data on the TALLOC_CTX handle->conn->mem_ctx, -you can set this function pointer to NULL. - - - - -Some useful MACROS for handle private data. - - - -#define SMB_VFS_HANDLE_GET_DATA(handle, datap, type, ret) { \ - if (!(handle)||((datap=(type *)(handle)->data)==NULL)) { \ - DEBUG(0,("%s() failed to get vfs_handle->data!\n",FUNCTION_MACRO)); \ - ret; \ - } \ -} - -#define SMB_VFS_HANDLE_SET_DATA(handle, datap, free_fn, type, ret) { \ - if (!(handle)) { \ - DEBUG(0,("%s() failed to set handle->data!\n",FUNCTION_MACRO)); \ - ret; \ - } else { \ - if ((handle)->free_data) { \ - (handle)->free_data(&(handle)->data); \ - } \ - (handle)->data = (void *)datap; \ - (handle)->free_data = free_fn; \ - } \ -} - -#define SMB_VFS_HANDLE_FREE_DATA(handle) { \ - if ((handle) && (handle)->free_data) { \ - (handle)->free_data(&(handle)->data); \ - } \ -} - - -How SMB_VFS_LAYER_TRANSPARENT functions can call the SMB_VFS_LAYER_OPAQUE functions. - -The easiest way to do this is to use the SMB_VFS_OPAQUE_* macros. - - - -... -/* File operations */ -#define SMB_VFS_OPAQUE_OPEN(conn, fname, flags, mode) \ - ((conn)->vfs_opaque.ops.open(\ - (conn)->vfs_opaque.handles.open,\ - (conn), (fname), (flags), (mode))) -#define SMB_VFS_OPAQUE_CLOSE(fsp, fd) \ - ((fsp)->conn->vfs_opaque.ops.close(\ - (fsp)->conn->vfs_opaque.handles.close,\ - (fsp), (fd))) -#define SMB_VFS_OPAQUE_READ(fsp, fd, data, n) \ - ((fsp)->conn->vfs_opaque.ops.read(\ - (fsp)->conn->vfs_opaque.handles.read,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_OPAQUE_WRITE(fsp, fd, data, n) \ - ((fsp)->conn->vfs_opaque.ops.write(\ - (fsp)->conn->vfs_opaque.handles.write,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_OPAQUE_LSEEK(fsp, fd, offset, whence) \ - ((fsp)->conn->vfs_opaque.ops.lseek(\ - (fsp)->conn->vfs_opaque.handles.lseek,\ - (fsp), (fd), (offset), (whence))) -#define SMB_VFS_OPAQUE_SENDFILE(tofd, fsp, fromfd, header, offset, count) \ - ((fsp)->conn->vfs_opaque.ops.sendfile(\ - (fsp)->conn->vfs_opaque.handles.sendfile,\ - (tofd), (fsp), (fromfd), (header), (offset), (count))) -... - - -How SMB_VFS_LAYER_TRANSPARENT functions can call the next modules functions. - -The easiest way to do this is to use the SMB_VFS_NEXT_* macros. - - - -... -/* File operations */ -#define SMB_VFS_NEXT_OPEN(handle, conn, fname, flags, mode) \ - ((handle)->vfs_next.ops.open(\ - (handle)->vfs_next.handles.open,\ - (conn), (fname), (flags), (mode))) -#define SMB_VFS_NEXT_CLOSE(handle, fsp, fd) \ - ((handle)->vfs_next.ops.close(\ - (handle)->vfs_next.handles.close,\ - (fsp), (fd))) -#define SMB_VFS_NEXT_READ(handle, fsp, fd, data, n) \ - ((handle)->vfs_next.ops.read(\ - (handle)->vfs_next.handles.read,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_NEXT_WRITE(handle, fsp, fd, data, n) \ - ((handle)->vfs_next.ops.write(\ - (handle)->vfs_next.handles.write,\ - (fsp), (fd), (data), (n))) -#define SMB_VFS_NEXT_LSEEK(handle, fsp, fd, offset, whence) \ - ((handle)->vfs_next.ops.lseek(\ - (handle)->vfs_next.handles.lseek,\ - (fsp), (fd), (offset), (whence))) -#define SMB_VFS_NEXT_SENDFILE(handle, tofd, fsp, fromfd, header, offset, count) \ - ((handle)->vfs_next.ops.sendfile(\ - (handle)->vfs_next.handles.sendfile,\ - (tofd), (fsp), (fromfd), (header), (offset), (count))) -... - - - - - - - -Upgrading to the New VFS Interface - - -Upgrading from 2.2.* and 3.0aplha modules - - - -Add "vfs_handle_struct *handle, " as first parameter to all vfs operation functions. -e.g. example_connect(connection_struct *conn, const char *service, const char *user); --> example_connect(vfs_handle_struct *handle, connection_struct *conn, const char *service, const char *user); - - - -Replace "default_vfs_ops." with "smb_vfs_next_". -e.g. default_vfs_ops.connect(conn, service, user); --> smb_vfs_next_connect(conn, service, user); - - - -Uppercase all "smb_vfs_next_*" functions. -e.g. smb_vfs_next_connect(conn, service, user); --> SMB_VFS_NEXT_CONNECT(conn, service, user); - - - -Add "handle, " as first parameter to all SMB_VFS_NEXT_*() calls. -e.g. SMB_VFS_NEXT_CONNECT(conn, service, user); --> SMB_VFS_NEXT_CONNECT(handle, conn, service, user); - - - -(Only for 2.2.* modules) -Convert the old struct vfs_ops example_ops to -a vfs_op_tuple example_op_tuples[] array. -e.g. - -struct vfs_ops example_ops = { - /* Disk operations */ - example_connect, /* connect */ - example_disconnect, /* disconnect */ - NULL, /* disk free * - /* Directory operations */ - NULL, /* opendir */ - NULL, /* readdir */ - NULL, /* mkdir */ - NULL, /* rmdir */ - NULL, /* closedir */ - /* File operations */ - NULL, /* open */ - NULL, /* close */ - NULL, /* read */ - NULL, /* write */ - NULL, /* lseek */ - NULL, /* sendfile */ - NULL, /* rename */ - NULL, /* fsync */ - example_stat, /* stat */ - example_fstat, /* fstat */ - example_lstat, /* lstat */ - NULL, /* unlink */ - NULL, /* chmod */ - NULL, /* fchmod */ - NULL, /* chown */ - NULL, /* fchown */ - NULL, /* chdir */ - NULL, /* getwd */ - NULL, /* utime */ - NULL, /* ftruncate */ - NULL, /* lock */ - NULL, /* symlink */ - NULL, /* readlink */ - NULL, /* link */ - NULL, /* mknod */ - NULL, /* realpath */ - NULL, /* fget_nt_acl */ - NULL, /* get_nt_acl */ - NULL, /* fset_nt_acl */ - NULL, /* set_nt_acl */ - - NULL, /* chmod_acl */ - NULL, /* fchmod_acl */ - - NULL, /* sys_acl_get_entry */ - NULL, /* sys_acl_get_tag_type */ - NULL, /* sys_acl_get_permset */ - NULL, /* sys_acl_get_qualifier */ - NULL, /* sys_acl_get_file */ - NULL, /* sys_acl_get_fd */ - NULL, /* sys_acl_clear_perms */ - NULL, /* sys_acl_add_perm */ - NULL, /* sys_acl_to_text */ - NULL, /* sys_acl_init */ - NULL, /* sys_acl_create_entry */ - NULL, /* sys_acl_set_tag_type */ - NULL, /* sys_acl_set_qualifier */ - NULL, /* sys_acl_set_permset */ - NULL, /* sys_acl_valid */ - NULL, /* sys_acl_set_file */ - NULL, /* sys_acl_set_fd */ - NULL, /* sys_acl_delete_def_file */ - NULL, /* sys_acl_get_perm */ - NULL, /* sys_acl_free_text */ - NULL, /* sys_acl_free_acl */ - NULL /* sys_acl_free_qualifier */ -}; - --> - -static vfs_op_tuple example_op_tuples[] = { - {SMB_VFS_OP(example_connect), SMB_VFS_OP_CONNECT, SMB_VFS_LAYER_TRANSPARENT}, - {SMB_VFS_OP(example_disconnect), SMB_VFS_OP_DISCONNECT, SMB_VFS_LAYER_TRANSPARENT}, - - {SMB_VFS_OP(example_fstat), SMB_VFS_OP_FSTAT, SMB_VFS_LAYER_TRANSPARENT}, - {SMB_VFS_OP(example_stat), SMB_VFS_OP_STAT, SMB_VFS_LAYER_TRANSPARENT}, - {SMB_VFS_OP(example_lstat), SMB_VFS_OP_LSTAT, SMB_VFS_LAYER_TRANSPARENT}, - - {SMB_VFS_OP(NULL), SMB_VFS_OP_NOOP, SMB_VFS_LAYER_NOOP} -}; - - - - -Move the example_op_tuples[] array to the end of the file. - - - -Add the init_module() function at the end of the file. -e.g. - -NTSTATUS init_module(void) -{ - return smb_register_vfs(SMB_VFS_INTERFACE_VERSION,"example",example_op_tuples); -} - - - - -Check if your vfs_init() function does more then just prepare the vfs_ops structs or -remember the struct smb_vfs_handle_struct. - -If NOT you can remove the vfs_init() function. -If YES decide if you want to move the code to the example_connect() operation or to the init_module(). And then remove vfs_init(). - e.g. a debug class registration should go into init_module() and the allocation of private data should go to example_connect(). - - - - -(Only for 3.0alpha* modules) -Check if your vfs_done() function contains needed code. - -If NOT you can remove the vfs_done() function. -If YES decide if you can move the code to the example_disconnect() operation. Otherwise register a SMB_EXIT_EVENT with smb_register_exit_event(); (Described in the modules section) And then remove vfs_done(). e.g. the freeing of private data should go to example_disconnect(). - - - - - -Check if you have any global variables left. -Decide if it wouldn't be better to have this data on a connection basis. - - If NOT leave them as they are. (e.g. this could be the variable for the private debug class.) - If YES pack all this data into a struct. You can use handle->data to point to such a struct on a per connection basis. - - - e.g. if you have such a struct: - -struct example_privates { - char *some_string; - int db_connection; -}; - -first way of doing it: - -static int example_connect(vfs_handle_struct *handle, - connection_struct *conn, const char *service, - const char* user) -{ - struct example_privates *data = NULL; - - /* alloc our private data */ - data = (struct example_privates *)talloc_zero(conn->mem_ctx, sizeof(struct example_privates)); - if (!data) { - DEBUG(0,("talloc_zero() failed\n")); - return -1; - } - - /* init out private data */ - data->some_string = talloc_strdup(conn->mem_ctx,"test"); - if (!data->some_string) { - DEBUG(0,("talloc_strdup() failed\n")); - return -1; - } - - data->db_connection = open_db_conn(); - - /* and now store the private data pointer in handle->data - * we don't need to specify a free_function here because - * we use the connection TALLOC context. - * (return -1 if something failed.) - */ - VFS_HANDLE_SET_DATA(handle, data, NULL, struct example_privates, return -1); - - return SMB_VFS_NEXT_CONNECT(handle,conn,service,user); -} - -static int example_close(vfs_handle_struct *handle, files_struct *fsp, int fd) -{ - struct example_privates *data = NULL; - - /* get the pointer to our private data - * return -1 if something failed - */ - SMB_VFS_HANDLE_GET_DATA(handle, data, struct example_privates, return -1); - - /* do something here...*/ - DEBUG(0,("some_string: %s\n",data->some_string)); - - return SMB_VFS_NEXT_CLOSE(handle, fsp, fd); -} - -second way of doing it: - -static void free_example_privates(void **datap) -{ - struct example_privates *data = (struct example_privates *)*datap; - - SAFE_FREE(data->some_string); - SAFE_FREE(data); - - *datap = NULL; - - return; -} - -static int example_connect(vfs_handle_struct *handle, - connection_struct *conn, const char *service, - const char* user) -{ - struct example_privates *data = NULL; - - /* alloc our private data */ - data = (struct example_privates *)malloc(sizeof(struct example_privates)); - if (!data) { - DEBUG(0,("malloc() failed\n")); - return -1; - } - - /* init out private data */ - data->some_string = strdup("test"); - if (!data->some_string) { - DEBUG(0,("strdup() failed\n")); - return -1; - } - - data->db_connection = open_db_conn(); - - /* and now store the private data pointer in handle->data - * we need to specify a free_function because we used malloc() and strdup(). - * (return -1 if something failed.) - */ - SMB_VFS_HANDLE_SET_DATA(handle, data, free_example_privates, struct example_privates, return -1); - - return SMB_VFS_NEXT_CONNECT(handle,conn,service,user); -} - -static int example_close(vfs_handle_struct *handle, files_struct *fsp, int fd) -{ - struct example_privates *data = NULL; - - /* get the pointer to our private data - * return -1 if something failed - */ - SMB_VFS_HANDLE_GET_DATA(handle, data, struct example_privates, return -1); - - /* do something here...*/ - DEBUG(0,("some_string: %s\n",data->some_string)); - - return SMB_VFS_NEXT_CLOSE(handle, fsp, fd); -} - - - - -To make it easy to build 3rd party modules it would be usefull to provide -configure.in, (configure), install.sh and Makefile.in with the module. -(Take a look at the example in examples/VFS.) - - - -The configure script accepts to specify -the path to the samba source tree. -It also accept which lets the compiler -give you more warnings. - - - -The idea is that you can extend this -configure.in and Makefile.in scripts -for your module. - - - -Compiling & Testing... - -./configure ... -make -Try to fix all compiler warnings -make -Testing, Testing, Testing ... - - - - - - - - -Some Notes - - -Implement TRANSPARENT functions - - -Avoid writing functions like this: - - -static int example_close(vfs_handle_struct *handle, files_struct *fsp, int fd) -{ - return SMB_VFS_NEXT_CLOSE(handle, fsp, fd); -} - - -Overload only the functions you really need to! - - - - - -Implement OPAQUE functions - - -If you want to just implement a better version of a -default samba opaque function -(e.g. like a disk_free() function for a special filesystem) -it's ok to just overload that specific function. - - - -If you want to implement a database filesystem or -something different from a posix filesystem. -Make sure that you overload every vfs operation!!! - - -Functions your FS does not support should be overloaded by something like this: -e.g. for a readonly filesystem. - - - -static int example_rename(vfs_handle_struct *handle, connection_struct *conn, - char *oldname, char *newname) -{ - DEBUG(10,("function rename() not allowed on vfs 'example'\n")); - errno = ENOSYS; - return -1; -} - - - - - - - -- cgit