cregit-Linux how code gets into the kernel

Release 4.10 drivers/hv/hv_fcopy.c

Directory: drivers/hv
/*
 * 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/nls.h>
#include <linux/workqueue.h>
#include <linux/hyperv.h>
#include <linux/sched.h>

#include "hyperv_vmbus.h"
#include "hv_utils_transport.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.
 */

static struct {
	
int state;   /* hvutil_device_state */
	
int recv_len; /* number of bytes received. */
	
struct hv_fcopy_hdr  *fcopy_msg; /* current message */
	
struct vmbus_channel *recv_channel; /* chn we got the request */
	
u64 recv_req_id; /* request ID. */
} 
fcopy_transaction;

static void fcopy_respond_to_host(int error);
static void fcopy_send_data(struct work_struct *dummy);
static void fcopy_timeout_func(struct work_struct *dummy);
static DECLARE_DELAYED_WORK(fcopy_timeout_work, fcopy_timeout_func);
static DECLARE_WORK(fcopy_send_work, fcopy_send_data);

static const char fcopy_devname[] = "vmbus/hv_fcopy";

static u8 *recv_buffer;

static struct hvutil_transport *hvt;
/*
 * This state maintains the version number registered by the daemon.
 */

static int dm_reg_value;


static void fcopy_poll_wrapper(void *channel) { /* Transaction is finished, reset the state here to avoid races. */ fcopy_transaction.state = HVUTIL_READY; hv_fcopy_onchannelcallback(channel); }

Contributors

PersonTokensPropCommitsCommitProp
olaf heringolaf hering22100.00%1100.00%
Total22100.00%1100.00%


static void fcopy_timeout_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); hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper); }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan1661.54%125.00%
vitaly kuznetsovvitaly kuznetsov830.77%250.00%
olaf heringolaf hering27.69%125.00%
Total26100.00%4100.00%


static void fcopy_register_done(void) { pr_debug("FCP: userspace daemon registered\n"); hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper); }

Contributors

PersonTokensPropCommitsCommitProp
vitaly kuznetsovvitaly kuznetsov22100.00%1100.00%
Total22100.00%1100.00%


static int fcopy_handle_handshake(u32 version) { u32 our_ver = FCOPY_CURRENT_VERSION; switch (version) { case FCOPY_VERSION_0: /* Daemon doesn't expect us to reply */ dm_reg_value = version; break; case FCOPY_VERSION_1: /* Daemon expects us to reply with our own version */ if (hvutil_transport_send(hvt, &our_ver, sizeof(our_ver), fcopy_register_done)) return -EFAULT; dm_reg_value = 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_debug("FCP: userspace daemon ver. %d connected\n", version); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
vitaly kuznetsovvitaly kuznetsov4357.33%375.00%
ky srinivasanky srinivasan3242.67%125.00%
Total75100.00%4100.00%


static void fcopy_send_data(struct work_struct *dummy) { struct hv_start_fcopy *smsg_out = NULL; int operation = fcopy_transaction.fcopy_msg->operation; struct hv_start_fcopy *smsg_in; void *out_src; int rc, out_len; /* * 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: out_len = sizeof(struct hv_start_fcopy); smsg_out = kzalloc(sizeof(*smsg_out), GFP_KERNEL); if (!smsg_out) return; 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; out_src = smsg_out; break; default: out_src = fcopy_transaction.fcopy_msg; out_len = fcopy_transaction.recv_len; break; } fcopy_transaction.state = HVUTIL_USERSPACE_REQ; rc = hvutil_transport_send(hvt, out_src, out_len, NULL); if (rc) { pr_debug("FCP: failed to communicate to the daemon: %d\n", rc); if (cancel_delayed_work_sync(&fcopy_timeout_work)) { fcopy_respond_to_host(HV_E_FAIL); fcopy_transaction.state = HVUTIL_READY; } } kfree(smsg_out); return; }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan13353.85%125.00%
vitaly kuznetsovvitaly kuznetsov11446.15%375.00%
Total247100.00%4100.00%

/* * 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; 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); }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan100100.00%1100.00%
Total100100.00%1100.00%


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.state > HVUTIL_READY) 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.recv_len = recvlen; fcopy_transaction.recv_req_id = requestid; fcopy_transaction.fcopy_msg = fcopy_msg; if (fcopy_transaction.state < HVUTIL_READY) { /* Userspace is not registered yet */ fcopy_respond_to_host(HV_E_FAIL); return; } fcopy_transaction.state = HVUTIL_HOSTMSG_RECEIVED; /* * Send the information to the user-level daemon. */ schedule_work(&fcopy_send_work); schedule_delayed_work(&fcopy_timeout_work, HV_UTIL_TIMEOUT * HZ); return; } icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE; vmbus_sendpacket(channel, recv_buffer, recvlen, requestid, VM_PKT_DATA_INBAND, 0); }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan20285.96%240.00%
vitaly kuznetsovvitaly kuznetsov3314.04%360.00%
Total235100.00%5100.00%

/* Callback when data is received from userspace */
static int fcopy_on_msg(void *msg, int len) { int *val = (int *)msg; if (len != sizeof(int)) return -EINVAL; if (fcopy_transaction.state == HVUTIL_DEVICE_INIT) return fcopy_handle_handshake(*val); if (fcopy_transaction.state != HVUTIL_USERSPACE_REQ) return -EINVAL; /* * Complete the transaction by forwarding the result * to the host. But first, cancel the timeout. */ if (cancel_delayed_work_sync(&fcopy_timeout_work)) { fcopy_transaction.state = HVUTIL_USERSPACE_RECV; fcopy_respond_to_host(*val); hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper); } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
vitaly kuznetsovvitaly kuznetsov5152.04%466.67%
ky srinivasanky srinivasan4545.92%116.67%
olaf heringolaf hering22.04%116.67%
Total98100.00%6100.00%


static void fcopy_on_reset(void) { /* * The daemon has exited; reset the state. */ fcopy_transaction.state = HVUTIL_DEVICE_INIT; if (cancel_delayed_work_sync(&fcopy_timeout_work)) fcopy_respond_to_host(HV_E_FAIL); }

Contributors

PersonTokensPropCommitsCommitProp
dexuan cuidexuan cui1346.43%116.67%
vitaly kuznetsovvitaly kuznetsov828.57%350.00%
ky srinivasanky srinivasan621.43%116.67%
fengguang wufengguang wu13.57%116.67%
Total28100.00%6100.00%


int hv_fcopy_init(struct hv_util_service *srv) { recv_buffer = srv->recv_buffer; fcopy_transaction.recv_channel = srv->channel; /* * 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.state = HVUTIL_DEVICE_INIT; hvt = hvutil_transport_init(fcopy_devname, 0, 0, fcopy_on_msg, fcopy_on_reset); if (!hvt) return -EFAULT; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan3662.07%250.00%
vitaly kuznetsovvitaly kuznetsov2237.93%250.00%
Total58100.00%4100.00%


void hv_fcopy_deinit(void) { fcopy_transaction.state = HVUTIL_DEVICE_DYING; cancel_delayed_work_sync(&fcopy_timeout_work); hvutil_transport_destroy(hvt); }

Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan1354.17%125.00%
vitaly kuznetsovvitaly kuznetsov1145.83%375.00%
Total24100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
ky srinivasanky srinivasan67763.04%321.43%
vitaly kuznetsovvitaly kuznetsov35733.24%857.14%
olaf heringolaf hering262.42%17.14%
dexuan cuidexuan cui131.21%17.14%
fengguang wufengguang wu10.09%17.14%
Total1074100.00%14100.00%
Directory: drivers/hv
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.