| 0,0 → 1,411 |
|---|
| /* |
| * Copyright (c) 2008 Jakub Jermar |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup fs |
| * @{ |
| */ |
| |
| /** |
| * @file vfs_register.c |
| * @brief |
| */ |
| |
| #include <ipc/ipc.h> |
| #include <ipc/services.h> |
| #include <async.h> |
| #include <fibril.h> |
| #include <errno.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <ctype.h> |
| #include <bool.h> |
| #include <futex.h> |
| #include <libadt/list.h> |
| #include <as.h> |
| #include <assert.h> |
| #include <atomic.h> |
| #include "vfs.h" |
| |
| atomic_t fs_head_futex = FUTEX_INITIALIZER; |
| link_t fs_head; |
| |
| atomic_t fs_handle_next = { |
| .count = 1 |
| }; |
| |
| /** Verify the VFS info structure. |
| * |
| * @param info Info structure to be verified. |
| * |
| * @return Non-zero if the info structure is sane, zero otherwise. |
| */ |
| static bool vfs_info_sane(vfs_info_t *info) |
| { |
| int i; |
| |
| /* |
| * Check if the name is non-empty and is composed solely of ASCII |
| * characters [a-z]+[a-z0-9_-]*. |
| */ |
| if (!islower(info->name[0])) { |
| dprintf("The name doesn't start with a lowercase character.\n"); |
| return false; |
| } |
| for (i = 1; i < FS_NAME_MAXLEN; i++) { |
| if (!(islower(info->name[i]) || isdigit(info->name[i])) && |
| (info->name[i] != '-') && (info->name[i] != '_')) { |
| if (info->name[i] == '\0') { |
| break; |
| } else { |
| dprintf("The name contains illegal " |
| "characters.\n"); |
| return false; |
| } |
| } |
| } |
| /* |
| * This check is not redundant. It ensures that the name is |
| * NULL-terminated, even if FS_NAME_MAXLEN characters are used. |
| */ |
| if (info->name[i] != '\0') { |
| dprintf("The name is not properly NULL-terminated.\n"); |
| return false; |
| } |
| |
| |
| /* |
| * Check if the FS implements mandatory VFS operations. |
| */ |
| if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_LOOKUP)] != VFS_OP_DEFINED) { |
| dprintf("Operation VFS_LOOKUP not defined by the client.\n"); |
| return false; |
| } |
| if (info->ops[IPC_METHOD_TO_VFS_OP(VFS_READ)] != VFS_OP_DEFINED) { |
| dprintf("Operation VFS_READ not defined by the client.\n"); |
| return false; |
| } |
| |
| /* |
| * Check if each operation is either not defined, defined or default. |
| */ |
| for (i = VFS_FIRST; i < VFS_LAST_CLNT; i++) { |
| if ((info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_NULL) && |
| (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFAULT) && |
| (info->ops[IPC_METHOD_TO_VFS_OP(i)] != VFS_OP_DEFINED)) { |
| dprintf("Operation info not understood.\n"); |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** VFS_REGISTER protocol function. |
| * |
| * @param rid Hash of the call with the request. |
| * @param request Call structure with the request. |
| */ |
| void vfs_register(ipc_callid_t rid, ipc_call_t *request) |
| { |
| ipc_callid_t callid; |
| ipc_call_t call; |
| int rc; |
| size_t size; |
| |
| dprintf("Processing VFS_REGISTER request received from %p.\n", |
| request->in_phone_hash); |
| |
| /* |
| * The first call has to be IPC_M_DATA_SEND in which we receive the |
| * VFS info structure from the client FS. |
| */ |
| if (!ipc_data_write_receive(&callid, &size)) { |
| /* |
| * The client doesn't obey the same protocol as we do. |
| */ |
| dprintf("Receiving of VFS info failed.\n"); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| dprintf("VFS info received, size = %d\n", size); |
| |
| /* |
| * We know the size of the VFS info structure. See if the client |
| * understands this easy concept too. |
| */ |
| if (size != sizeof(vfs_info_t)) { |
| /* |
| * The client is sending us something, which cannot be |
| * the info structure. |
| */ |
| dprintf("Received VFS info has bad size.\n"); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| /* |
| * Allocate and initialize a buffer for the fs_info structure. |
| */ |
| fs_info_t *fs_info; |
| fs_info = (fs_info_t *) malloc(sizeof(fs_info_t)); |
| if (!fs_info) { |
| dprintf("Could not allocate memory for FS info.\n"); |
| ipc_answer_0(callid, ENOMEM); |
| ipc_answer_0(rid, ENOMEM); |
| return; |
| } |
| link_initialize(&fs_info->fs_link); |
| futex_initialize(&fs_info->phone_futex, 1); |
| |
| rc = ipc_data_write_finalize(callid, &fs_info->vfs_info, size); |
| if (rc != EOK) { |
| dprintf("Failed to deliver the VFS info into our AS, rc=%d.\n", |
| rc); |
| free(fs_info); |
| ipc_answer_0(callid, rc); |
| ipc_answer_0(rid, rc); |
| return; |
| } |
| |
| dprintf("VFS info delivered.\n"); |
| |
| if (!vfs_info_sane(&fs_info->vfs_info)) { |
| free(fs_info); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| futex_down(&fs_head_futex); |
| fibril_inc_sercount(); |
| |
| /* |
| * Check for duplicit registrations. |
| */ |
| if (fs_name_to_handle(fs_info->vfs_info.name, false)) { |
| /* |
| * We already register a fs like this. |
| */ |
| dprintf("FS is already registered.\n"); |
| fibril_dec_sercount(); |
| futex_up(&fs_head_futex); |
| free(fs_info); |
| ipc_answer_0(callid, EEXISTS); |
| ipc_answer_0(rid, EEXISTS); |
| return; |
| } |
| |
| /* |
| * Add fs_info to the list of registered FS's. |
| */ |
| dprintf("Inserting FS into the list of registered file systems.\n"); |
| list_append(&fs_info->fs_link, &fs_head); |
| |
| /* |
| * Now we want the client to send us the IPC_M_CONNECT_TO_ME call so |
| * that a callback connection is created and we have a phone through |
| * which to forward VFS requests to it. |
| */ |
| callid = async_get_call(&call); |
| if (IPC_GET_METHOD(call) != IPC_M_CONNECT_TO_ME) { |
| dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
| list_remove(&fs_info->fs_link); |
| fibril_dec_sercount(); |
| futex_up(&fs_head_futex); |
| free(fs_info); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| fs_info->phone = IPC_GET_ARG5(call); |
| ipc_answer_0(callid, EOK); |
| |
| dprintf("Callback connection to FS created.\n"); |
| |
| /* |
| * The client will want us to send him the address space area with PLB. |
| */ |
| |
| if (!ipc_share_in_receive(&callid, &size)) { |
| dprintf("Unexpected call, method = %d\n", IPC_GET_METHOD(call)); |
| list_remove(&fs_info->fs_link); |
| fibril_dec_sercount(); |
| futex_up(&fs_head_futex); |
| ipc_hangup(fs_info->phone); |
| free(fs_info); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| /* |
| * We can only send the client address space area PLB_SIZE bytes long. |
| */ |
| if (size != PLB_SIZE) { |
| dprintf("Client suggests wrong size of PFB, size = %d\n", size); |
| list_remove(&fs_info->fs_link); |
| fibril_dec_sercount(); |
| futex_up(&fs_head_futex); |
| ipc_hangup(fs_info->phone); |
| free(fs_info); |
| ipc_answer_0(callid, EINVAL); |
| ipc_answer_0(rid, EINVAL); |
| return; |
| } |
| |
| /* |
| * Commit to read-only sharing the PLB with the client. |
| */ |
| (void) ipc_share_in_finalize(callid, plb, |
| AS_AREA_READ | AS_AREA_CACHEABLE); |
| |
| dprintf("Sharing PLB.\n"); |
| |
| /* |
| * That was it. The FS has been registered. |
| * In reply to the VFS_REGISTER request, we assign the client file |
| * system a global file system handle. |
| */ |
| fs_info->fs_handle = (fs_handle_t) atomic_postinc(&fs_handle_next); |
| ipc_answer_1(rid, EOK, (ipcarg_t) fs_info->fs_handle); |
| |
| fibril_dec_sercount(); |
| futex_up(&fs_head_futex); |
| |
| dprintf("\"%.*s\" filesystem successfully registered, handle=%d.\n", |
| FS_NAME_MAXLEN, fs_info->vfs_info.name, fs_info->fs_handle); |
| } |
| |
| /** For a given file system handle, implement policy for allocating a phone. |
| * |
| * @param handle File system handle. |
| * |
| * @return Phone over which a multi-call request can be safely |
| * sent. Return 0 if no phone was found. |
| */ |
| int vfs_grab_phone(fs_handle_t handle) |
| { |
| /* |
| * For now, we don't try to be very clever and very fast. |
| * We simply lookup the phone in the fs_head list. We currently don't |
| * open any additional phones (even though that itself would be pretty |
| * straightforward; housekeeping multiple open phones to a FS task would |
| * be more demanding). Instead, we simply take the respective |
| * phone_futex and keep it until vfs_release_phone(). |
| */ |
| futex_down(&fs_head_futex); |
| link_t *cur; |
| fs_info_t *fs; |
| for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
| fs = list_get_instance(cur, fs_info_t, fs_link); |
| if (fs->fs_handle == handle) { |
| futex_up(&fs_head_futex); |
| /* |
| * For now, take the futex unconditionally. |
| * Oh yeah, serialization rocks. |
| * It will be up'ed in vfs_release_phone(). |
| */ |
| futex_down(&fs->phone_futex); |
| /* |
| * Avoid deadlock with other fibrils in the same thread |
| * by disabling fibril preemption. |
| */ |
| fibril_inc_sercount(); |
| return fs->phone; |
| } |
| } |
| futex_up(&fs_head_futex); |
| return 0; |
| } |
| |
| /** Tell VFS that the phone is in use for any request. |
| * |
| * @param phone Phone to FS task. |
| */ |
| void vfs_release_phone(int phone) |
| { |
| bool found = false; |
| |
| /* |
| * Undo the fibril_inc_sercount() done in vfs_grab_phone(). |
| */ |
| fibril_dec_sercount(); |
| |
| futex_down(&fs_head_futex); |
| link_t *cur; |
| for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
| fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
| if (fs->phone == phone) { |
| found = true; |
| futex_up(&fs_head_futex); |
| futex_up(&fs->phone_futex); |
| return; |
| } |
| } |
| futex_up(&fs_head_futex); |
| |
| /* |
| * Not good to get here. |
| */ |
| assert(found == true); |
| } |
| |
| /** Convert file system name to its handle. |
| * |
| * @param name File system name. |
| * @param lock If true, the function will down and up the |
| * fs_head_futex. |
| * |
| * @return File system handle or zero if file system not found. |
| */ |
| fs_handle_t fs_name_to_handle(char *name, bool lock) |
| { |
| int handle = 0; |
| |
| if (lock) |
| futex_down(&fs_head_futex); |
| link_t *cur; |
| for (cur = fs_head.next; cur != &fs_head; cur = cur->next) { |
| fs_info_t *fs = list_get_instance(cur, fs_info_t, fs_link); |
| if (strncmp(fs->vfs_info.name, name, |
| sizeof(fs->vfs_info.name)) == 0) { |
| handle = fs->fs_handle; |
| break; |
| } |
| } |
| if (lock) |
| futex_up(&fs_head_futex); |
| return handle; |
| } |
| |
| /** |
| * @} |
| */ |