diff options
Diffstat (limited to 'drivers/hv/hv_fcopy.c')
| -rw-r--r-- | drivers/hv/hv_fcopy.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c new file mode 100644 index 000000000000..285b5e210a09 --- /dev/null +++ b/drivers/hv/hv_fcopy.c @@ -0,0 +1,414 @@ +/* + * An implementation of file copy service. + * + * Copyright (C) 2014, Microsoft, Inc. + * + * Author : K. Y. Srinivasan <ksrinivasan@novell.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for more + * details. + * + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/semaphore.h> +#include <linux/fs.h> +#include <linux/nls.h> +#include <linux/workqueue.h> +#include <linux/cdev.h> +#include <linux/hyperv.h> +#include <linux/sched.h> +#include <linux/uaccess.h> +#include <linux/miscdevice.h> + +#include "hyperv_vmbus.h" + +#define WIN8_SRV_MAJOR 1 +#define WIN8_SRV_MINOR 1 +#define WIN8_SRV_VERSION (WIN8_SRV_MAJOR << 16 | WIN8_SRV_MINOR) + +/* + * Global state maintained for transaction that is being processed. + * For a class of integration services, including the "file copy service", + * the specified protocol is a "request/response" protocol which means that + * there can only be single outstanding transaction from the host at any + * given point in time. We use this to simplify memory management in this + * driver - we cache and process only one message at a time. + * + * While the request/response protocol is guaranteed by the host, we further + * ensure this by serializing packet processing in this driver - we do not + * read additional packets from the VMBUs until the current packet is fully + * handled. + * + * The transaction "active" state is set when we receive a request from the + * host and we cleanup this state when the transaction is completed - when we + * respond to the host with our response. When the transaction active state is + * set, we defer handling incoming packets. + */ + +static struct { + bool active; /* transaction status - active or not */ + int recv_len; /* number of bytes received. */ + struct hv_fcopy_hdr *fcopy_msg; /* current message */ + struct hv_start_fcopy message; /* sent to daemon */ + struct vmbus_channel *recv_channel; /* chn we got the request */ + u64 recv_req_id; /* request ID. */ + void *fcopy_context; /* for the channel callback */ + struct semaphore read_sema; +} fcopy_transaction; + +static bool opened; /* currently device opened */ + +/* + * Before we can accept copy messages from the host, we need + * to handshake with the user level daemon. This state tracks + * if we are in the handshake phase. + */ +static bool in_hand_shake = true; +static void fcopy_send_data(void); +static void fcopy_respond_to_host(int error); +static void fcopy_work_func(struct work_struct *dummy); +static DECLARE_DELAYED_WORK(fcopy_work, fcopy_work_func); +static u8 *recv_buffer; + +static void fcopy_work_func(struct work_struct *dummy) +{ + /* + * If the timer fires, the user-mode component has not responded; + * process the pending transaction. + */ + fcopy_respond_to_host(HV_E_FAIL); +} + +static int fcopy_handle_handshake(u32 version) +{ + switch (version) { + case FCOPY_CURRENT_VERSION: + break; + default: + /* + * For now we will fail the registration. + * If and when we have multiple versions to + * deal with, we will be backward compatible. + * We will add this code when needed. + */ + return -EINVAL; + } + pr_info("FCP: user-mode registering done. Daemon version: %d\n", + version); + fcopy_transaction.active = false; + if (fcopy_transaction.fcopy_context) + hv_fcopy_onchannelcallback(fcopy_transaction.fcopy_context); + in_hand_shake = false; + return 0; +} + +static void fcopy_send_data(void) +{ + struct hv_start_fcopy *smsg_out = &fcopy_transaction.message; + int operation = fcopy_transaction.fcopy_msg->operation; + struct hv_start_fcopy *smsg_in; + + /* + * The strings sent from the host are encoded in + * in utf16; convert it to utf8 strings. + * The host assures us that the utf16 strings will not exceed + * the max lengths specified. We will however, reserve room + * for the string terminating character - in the utf16s_utf8s() + * function we limit the size of the buffer where the converted + * string is placed to W_MAX_PATH -1 to guarantee + * that the strings can be properly terminated! + */ + + switch (operation) { + case START_FILE_COPY: + memset(smsg_out, 0, sizeof(struct hv_start_fcopy)); + smsg_out->hdr.operation = operation; + smsg_in = (struct hv_start_fcopy *)fcopy_transaction.fcopy_msg; + + utf16s_to_utf8s((wchar_t *)smsg_in->file_name, W_MAX_PATH, + UTF16_LITTLE_ENDIAN, + (__u8 *)smsg_out->file_name, W_MAX_PATH - 1); + + utf16s_to_utf8s((wchar_t *)smsg_in->path_name, W_MAX_PATH, + UTF16_LITTLE_ENDIAN, + (__u8 *)smsg_out->path_name, W_MAX_PATH - 1); + + smsg_out->copy_flags = smsg_in->copy_flags; + smsg_out->file_size = smsg_in->file_size; + break; + + default: + break; + } + up(&fcopy_transaction.read_sema); + return; +} + +/* + * Send a response back to the host. + */ + +static void +fcopy_respond_to_host(int error) +{ + struct icmsg_hdr *icmsghdr; + u32 buf_len; + struct vmbus_channel *channel; + u64 req_id; + + /* + * Copy the global state for completing the transaction. Note that + * only one transaction can be active at a time. This is guaranteed + * by the file copy protocol implemented by the host. Furthermore, + * the "transaction active" state we maintain ensures that there can + * only be one active transaction at a time. + */ + + buf_len = fcopy_transaction.recv_len; + channel = fcopy_transaction.recv_channel; + req_id = fcopy_transaction.recv_req_id; + + fcopy_transaction.active = false; + + icmsghdr = (struct icmsg_hdr *) + &recv_buffer[sizeof(struct vmbuspipe_hdr)]; + + if (channel->onchannel_callback == NULL) + /* + * We have raced with util driver being unloaded; + * silently return. + */ + return; + + icmsghdr->status = error; + icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; + vmbus_sendpacket(channel, recv_buffer, buf_len, req_id, + VM_PKT_DATA_INBAND, 0); +} + +void hv_fcopy_onchannelcallback(void *context) +{ + struct vmbus_channel *channel = context; + u32 recvlen; + u64 requestid; + struct hv_fcopy_hdr *fcopy_msg; + struct icmsg_hdr *icmsghdr; + struct icmsg_negotiate *negop = NULL; + int util_fw_version; + int fcopy_srv_version; + + if (fcopy_transaction.active) { + /* + * We will defer processing this callback once + * the current transaction is complete. + */ + fcopy_transaction.fcopy_context = context; + return; + } + + vmbus_recvpacket(channel, recv_buffer, PAGE_SIZE * 2, &recvlen, + &requestid); + if (recvlen <= 0) + return; + + icmsghdr = (struct icmsg_hdr *)&recv_buffer[ + sizeof(struct vmbuspipe_hdr)]; + if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) { + util_fw_version = UTIL_FW_VERSION; + fcopy_srv_version = WIN8_SRV_VERSION; + vmbus_prep_negotiate_resp(icmsghdr, negop, recv_buffer, + util_fw_version, fcopy_srv_version); + } else { + fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[ + sizeof(struct vmbuspipe_hdr) + + sizeof(struct icmsg_hdr)]; + + /* + * Stash away this global state for completing the + * transaction; note transactions are serialized. + */ + + fcopy_transaction.active = true; + fcopy_transaction.recv_len = recvlen; + fcopy_transaction.recv_channel = channel; + fcopy_transaction.recv_req_id = requestid; + fcopy_transaction.fcopy_msg = fcopy_msg; + + /* + * Send the information to the user-level daemon. + */ + fcopy_send_data(); + schedule_delayed_work(&fcopy_work, 5*HZ); + return; + } + icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; + vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, + VM_PKT_DATA_INBAND, 0); +} + +/* + * Create a char device that can support read/write for passing + * the payload. + */ + +static ssize_t fcopy_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + void *src; + size_t copy_size; + int operation; + + /* + * Wait until there is something to be read. + */ + if (down_interruptible(&fcopy_transaction.read_sema)) + return -EINTR; + + /* + * The channel may be rescinded and in this case, we will wakeup the + * the thread blocked on the semaphore and we will use the opened + * state to correctly handle this case. + */ + if (!opened) + return -ENODEV; + + operation = fcopy_transaction.fcopy_msg->operation; + + if (operation == START_FILE_COPY) { + src = &fcopy_transaction.message; + copy_size = sizeof(struct hv_start_fcopy); + if (count < copy_size) + return 0; + } else { + src = fcopy_transaction.fcopy_msg; + copy_size = sizeof(struct hv_do_fcopy); + if (count < copy_size) + return 0; + } + if (copy_to_user(buf, src, copy_size)) + return -EFAULT; + + return copy_size; +} + +static ssize_t fcopy_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int response = 0; + + if (count != sizeof(int)) + return -EINVAL; + + if (copy_from_user(&response, buf, sizeof(int))) + return -EFAULT; + + if (in_hand_shake) { + if (fcopy_handle_handshake(response)) + return -EINVAL; + return sizeof(int); + } + + /* + * Complete the transaction by forwarding the result + * to the host. But first, cancel the timeout. + */ + if (cancel_delayed_work_sync(&fcopy_work)) + fcopy_respond_to_host(response); + + return sizeof(int); +} + +int fcopy_open(struct inode *inode, struct file *f) +{ + /* + * The user level daemon that will open this device is + * really an extension of this driver. We can have only + * active open at a time. + */ + if (opened) + return -EBUSY; + + /* + * The daemon is alive; setup the state. + */ + opened = true; + return 0; +} + +int fcopy_release(struct inode *inode, struct file *f) +{ + /* + * The daemon has exited; reset the state. + */ + in_hand_shake = true; + opened = false; + return 0; +} + + +static const struct file_operations fcopy_fops = { + .read = fcopy_read, + .write = fcopy_write, + .release = fcopy_release, + .open = fcopy_open, +}; + +static struct miscdevice fcopy_misc = { + .minor = MISC_DYNAMIC_MINOR, + .name = "vmbus/hv_fcopy", + .fops = &fcopy_fops, +}; + +static int fcopy_dev_init(void) +{ + return misc_register(&fcopy_misc); +} + +static void fcopy_dev_deinit(void) +{ + + /* + * The device is going away - perhaps because the + * host has rescinded the channel. Setup state so that + * user level daemon can gracefully exit if it is blocked + * on the read semaphore. + */ + opened = false; + /* + * Signal the semaphore as the device is + * going away. + */ + up(&fcopy_transaction.read_sema); + misc_deregister(&fcopy_misc); +} + +int hv_fcopy_init(struct hv_util_service *srv) +{ + recv_buffer = srv->recv_buffer; + + /* + * When this driver loads, the user level daemon that + * processes the host requests may not yet be running. + * Defer processing channel callbacks until the daemon + * has registered. + */ + fcopy_transaction.active = true; + sema_init(&fcopy_transaction.read_sema, 0); + + return fcopy_dev_init(); +} + +void hv_fcopy_deinit(void) +{ + cancel_delayed_work_sync(&fcopy_work); + fcopy_dev_deinit(); +} |