Hyper-V is adding multiple low speed "speciality" synthetic devices.
Instead of writing a new kernel-level VMBus driver for each device,
make the devices accessible to user space through UIO-based
uio_hv_generic driver. Each device can then be supported by a user
space driver. This approach optimizes the development process and
provides flexibility to user space applications to control the key
interactions with the VMBus ring buffer.
The new synthetic devices are low speed devices that don't support
VMBus monitor bits, and so they must use vmbus_setevent() to notify
the host of ring buffer updates. These new devices also have smaller
ring buffer sizes which requires to add support for variable ring buffer
sizes.
Moreover, this patch series adds a new implementation of the fcopy
application that uses the new UIO driver. The older fcopy driver and
application will be phased out gradually. Development of other similar
userspace drivers is still underway.
Efforts have been made previously to implement this solution earlier.
Here are the discussions related to those attempts:
Attempt 1: Upgrade uio_hv_generic to cater to Underhill slow devices. But this was rejected due
to use of module parameters.
https://lore.kernel.org/lkml/[email protected]/
Attempt 2: Enable interrupt for low speed VMBus devices in uio_hv_generic and was rejected due to
unavailability of userspace driver for it.
https://lore.kernel.org/lkml/[email protected]/
Attempt 3: Wrote a new UIO driver but was rejected due to its complexity.
https://lore.kernel.org/lkml/[email protected]/
[V2]
- Went through internal review, got few reviewed-by from Long Li.
- Added more details in cover letter for previous attempts.
- Added more details in commit messages.
- Added comments for preferred ring sizes and there values.
- Removed need_sign arg from vmbus_txbr_write
- Change (4 * 4096) to 0x4000 for ring buffer size.
- Removed some unnecessary type casting.
- Removed rte_smp_rwmb as its duplicate of rte_compiler_barrier.
- Added more comment for rte_compiler_barrierx.
- Mentioned in file copyright header that this code is copied.
- Changed the print from "Registration failed" to "Signal to host failed".
- Fixed mask for rx buffer interrupt to 0 before waiting for interrupt.
Saurabh Sengar (7):
Drivers: hv: vmbus: Add utility function for querying ring size
uio_hv_generic: Query the ringbuffer size for device
uio_hv_generic: Enable interrupt for low speed VMBus devices
tools: hv: Add vmbus_bufring
tools: hv: Add new fcopy application based on uio driver
Drivers: hv: Remove fcopy driver
uio_hv_generic: Remove use of PAGE_SIZE
drivers/hv/Makefile | 2 +-
drivers/hv/channel_mgmt.c | 15 +-
drivers/hv/hv_fcopy.c | 427 ----------------------------
drivers/hv/hv_util.c | 12 -
drivers/hv/hyperv_vmbus.h | 5 +
drivers/uio/uio_hv_generic.c | 19 +-
include/linux/hyperv.h | 2 +
tools/hv/Build | 3 +-
tools/hv/Makefile | 10 +-
tools/hv/hv_fcopy_daemon.c | 266 ------------------
tools/hv/hv_fcopy_uio_daemon.c | 490 +++++++++++++++++++++++++++++++++
tools/hv/vmbus_bufring.c | 318 +++++++++++++++++++++
tools/hv/vmbus_bufring.h | 158 +++++++++++
13 files changed, 1002 insertions(+), 725 deletions(-)
delete mode 100644 drivers/hv/hv_fcopy.c
delete mode 100644 tools/hv/hv_fcopy_daemon.c
create mode 100644 tools/hv/hv_fcopy_uio_daemon.c
create mode 100644 tools/hv/vmbus_bufring.c
create mode 100644 tools/hv/vmbus_bufring.h
--
2.34.1
As the new fcopy driver using uio is introduced, remove obsolete driver
and application.
Signed-off-by: Saurabh Sengar <[email protected]>
Reviewed-by: Long Li <[email protected]>
---
[V2]
- Added Reviewed-by form Long Li
drivers/hv/Makefile | 2 +-
drivers/hv/hv_fcopy.c | 427 -------------------------------------
drivers/hv/hv_util.c | 12 --
tools/hv/hv_fcopy_daemon.c | 266 -----------------------
4 files changed, 1 insertion(+), 706 deletions(-)
delete mode 100644 drivers/hv/hv_fcopy.c
delete mode 100644 tools/hv/hv_fcopy_daemon.c
diff --git a/drivers/hv/Makefile b/drivers/hv/Makefile
index d76df5c8c2a9..b992c0ed182b 100644
--- a/drivers/hv/Makefile
+++ b/drivers/hv/Makefile
@@ -10,7 +10,7 @@ hv_vmbus-y := vmbus_drv.o \
hv.o connection.o channel.o \
channel_mgmt.o ring_buffer.o hv_trace.o
hv_vmbus-$(CONFIG_HYPERV_TESTING) += hv_debugfs.o
-hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_fcopy.o hv_utils_transport.o
+hv_utils-y := hv_util.o hv_kvp.o hv_snapshot.o hv_utils_transport.o
# Code that must be built-in
obj-$(subst m,y,$(CONFIG_HYPERV)) += hv_common.o
diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
deleted file mode 100644
index 922d83eb7ddf..000000000000
--- a/drivers/hv/hv_fcopy.c
+++ /dev/null
@@ -1,427 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * An implementation of file copy service.
- *
- * Copyright (C) 2014, Microsoft, Inc.
- *
- * Author : K. Y. Srinivasan <[email protected]>
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/nls.h>
-#include <linux/workqueue.h>
-#include <linux/hyperv.h>
-#include <linux/sched.h>
-#include <asm/hyperv-tlfs.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)
-
-#define FCOPY_VER_COUNT 1
-static const int fcopy_versions[] = {
- WIN8_SRV_VERSION
-};
-
-#define FW_VER_COUNT 1
-static const int fw_versions[] = {
- UTIL_FW_VERSION
-};
-
-/*
- * 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;
- tasklet_schedule(&((struct vmbus_channel *)channel)->callback_event);
-}
-
-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);
-}
-
-static void fcopy_register_done(void)
-{
- pr_debug("FCP: userspace daemon registered\n");
- hv_poll_channel(fcopy_transaction.recv_channel, fcopy_poll_wrapper);
-}
-
-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;
-}
-
-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
- * 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;
-
- case WRITE_TO_FILE:
- out_src = fcopy_transaction.fcopy_msg;
- out_len = sizeof(struct hv_do_fcopy);
- 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);
-}
-
-/*
- * 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);
-}
-
-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;
- int fcopy_srv_version;
-
- if (fcopy_transaction.state > HVUTIL_READY)
- return;
-
- if (vmbus_recvpacket(channel, recv_buffer, HV_HYP_PAGE_SIZE * 2, &recvlen, &requestid)) {
- pr_err_ratelimited("Fcopy request received. Could not read into recv buf\n");
- return;
- }
-
- if (!recvlen)
- return;
-
- /* Ensure recvlen is big enough to read header data */
- if (recvlen < ICMSG_HDR) {
- pr_err_ratelimited("Fcopy request received. Packet length too small: %d\n",
- recvlen);
- return;
- }
-
- icmsghdr = (struct icmsg_hdr *)&recv_buffer[
- sizeof(struct vmbuspipe_hdr)];
-
- if (icmsghdr->icmsgtype == ICMSGTYPE_NEGOTIATE) {
- if (vmbus_prep_negotiate_resp(icmsghdr,
- recv_buffer, recvlen,
- fw_versions, FW_VER_COUNT,
- fcopy_versions, FCOPY_VER_COUNT,
- NULL, &fcopy_srv_version)) {
-
- pr_info("FCopy IC version %d.%d\n",
- fcopy_srv_version >> 16,
- fcopy_srv_version & 0xFFFF);
- }
- } else if (icmsghdr->icmsgtype == ICMSGTYPE_FCOPY) {
- /* Ensure recvlen is big enough to contain hv_fcopy_hdr */
- if (recvlen < ICMSG_HDR + sizeof(struct hv_fcopy_hdr)) {
- pr_err_ratelimited("Invalid Fcopy hdr. Packet length too small: %u\n",
- recvlen);
- return;
- }
- fcopy_msg = (struct hv_fcopy_hdr *)&recv_buffer[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;
- } else {
- pr_err_ratelimited("Fcopy request received. Invalid msg type: %d\n",
- icmsghdr->icmsgtype);
- return;
- }
- icmsghdr->icflags = ICMSGHDRFLAG_TRANSACTION | ICMSGHDRFLAG_RESPONSE;
- vmbus_sendpacket(channel, recv_buffer, recvlen, requestid,
- VM_PKT_DATA_INBAND, 0);
-}
-
-/* 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;
-}
-
-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);
-}
-
-int hv_fcopy_init(struct hv_util_service *srv)
-{
- recv_buffer = srv->recv_buffer;
- fcopy_transaction.recv_channel = srv->channel;
- fcopy_transaction.recv_channel->max_pkt_size = HV_HYP_PAGE_SIZE * 2;
-
- /*
- * 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;
-}
-
-static void hv_fcopy_cancel_work(void)
-{
- cancel_delayed_work_sync(&fcopy_timeout_work);
- cancel_work_sync(&fcopy_send_work);
-}
-
-int hv_fcopy_pre_suspend(void)
-{
- struct vmbus_channel *channel = fcopy_transaction.recv_channel;
- struct hv_fcopy_hdr *fcopy_msg;
-
- /*
- * Fake a CANCEL_FCOPY message for the user space daemon in case the
- * daemon is in the middle of copying some file. It doesn't matter if
- * there is already a message pending to be delivered to the user
- * space since we force fcopy_transaction.state to be HVUTIL_READY, so
- * the user space daemon's write() will fail with EINVAL (see
- * fcopy_on_msg()), and the daemon will reset the device by closing
- * and re-opening it.
- */
- fcopy_msg = kzalloc(sizeof(*fcopy_msg), GFP_KERNEL);
- if (!fcopy_msg)
- return -ENOMEM;
-
- tasklet_disable(&channel->callback_event);
-
- fcopy_msg->operation = CANCEL_FCOPY;
-
- hv_fcopy_cancel_work();
-
- /* We don't care about the return value. */
- hvutil_transport_send(hvt, fcopy_msg, sizeof(*fcopy_msg), NULL);
-
- kfree(fcopy_msg);
-
- fcopy_transaction.state = HVUTIL_READY;
-
- /* tasklet_enable() will be called in hv_fcopy_pre_resume(). */
- return 0;
-}
-
-int hv_fcopy_pre_resume(void)
-{
- struct vmbus_channel *channel = fcopy_transaction.recv_channel;
-
- tasklet_enable(&channel->callback_event);
-
- return 0;
-}
-
-void hv_fcopy_deinit(void)
-{
- fcopy_transaction.state = HVUTIL_DEVICE_DYING;
-
- hv_fcopy_cancel_work();
-
- hvutil_transport_destroy(hvt);
-}
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 9c97c4065fe7..c4f525325790 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -154,14 +154,6 @@ static struct hv_util_service util_vss = {
.util_deinit = hv_vss_deinit,
};
-static struct hv_util_service util_fcopy = {
- .util_cb = hv_fcopy_onchannelcallback,
- .util_init = hv_fcopy_init,
- .util_pre_suspend = hv_fcopy_pre_suspend,
- .util_pre_resume = hv_fcopy_pre_resume,
- .util_deinit = hv_fcopy_deinit,
-};
-
static void perform_shutdown(struct work_struct *dummy)
{
orderly_poweroff(true);
@@ -700,10 +692,6 @@ static const struct hv_vmbus_device_id id_table[] = {
{ HV_VSS_GUID,
.driver_data = (unsigned long)&util_vss
},
- /* File copy GUID */
- { HV_FCOPY_GUID,
- .driver_data = (unsigned long)&util_fcopy
- },
{ },
};
diff --git a/tools/hv/hv_fcopy_daemon.c b/tools/hv/hv_fcopy_daemon.c
deleted file mode 100644
index 16d629b22c25..000000000000
--- a/tools/hv/hv_fcopy_daemon.c
+++ /dev/null
@@ -1,266 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * An implementation of host to guest copy functionality for Linux.
- *
- * Copyright (C) 2014, Microsoft, Inc.
- *
- * Author : K. Y. Srinivasan <[email protected]>
- */
-
-
-#include <sys/types.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <string.h>
-#include <errno.h>
-#include <linux/hyperv.h>
-#include <linux/limits.h>
-#include <syslog.h>
-#include <sys/stat.h>
-#include <fcntl.h>
-#include <getopt.h>
-
-static int target_fd;
-static char target_fname[PATH_MAX];
-static unsigned long long filesize;
-
-static int hv_start_fcopy(struct hv_start_fcopy *smsg)
-{
- int error = HV_E_FAIL;
- char *q, *p;
-
- filesize = 0;
- p = (char *)smsg->path_name;
- snprintf(target_fname, sizeof(target_fname), "%s/%s",
- (char *)smsg->path_name, (char *)smsg->file_name);
-
- syslog(LOG_INFO, "Target file name: %s", target_fname);
- /*
- * Check to see if the path is already in place; if not,
- * create if required.
- */
- while ((q = strchr(p, '/')) != NULL) {
- if (q == p) {
- p++;
- continue;
- }
- *q = '\0';
- if (access((char *)smsg->path_name, F_OK)) {
- if (smsg->copy_flags & CREATE_PATH) {
- if (mkdir((char *)smsg->path_name, 0755)) {
- syslog(LOG_ERR, "Failed to create %s",
- (char *)smsg->path_name);
- goto done;
- }
- } else {
- syslog(LOG_ERR, "Invalid path: %s",
- (char *)smsg->path_name);
- goto done;
- }
- }
- p = q + 1;
- *q = '/';
- }
-
- if (!access(target_fname, F_OK)) {
- syslog(LOG_INFO, "File: %s exists", target_fname);
- if (!(smsg->copy_flags & OVER_WRITE)) {
- error = HV_ERROR_ALREADY_EXISTS;
- goto done;
- }
- }
-
- target_fd = open(target_fname,
- O_RDWR | O_CREAT | O_TRUNC | O_CLOEXEC, 0744);
- if (target_fd == -1) {
- syslog(LOG_INFO, "Open Failed: %s", strerror(errno));
- goto done;
- }
-
- error = 0;
-done:
- if (error)
- target_fname[0] = '\0';
- return error;
-}
-
-static int hv_copy_data(struct hv_do_fcopy *cpmsg)
-{
- ssize_t bytes_written;
- int ret = 0;
-
- bytes_written = pwrite(target_fd, cpmsg->data, cpmsg->size,
- cpmsg->offset);
-
- filesize += cpmsg->size;
- if (bytes_written != cpmsg->size) {
- switch (errno) {
- case ENOSPC:
- ret = HV_ERROR_DISK_FULL;
- break;
- default:
- ret = HV_E_FAIL;
- break;
- }
- syslog(LOG_ERR, "pwrite failed to write %llu bytes: %ld (%s)",
- filesize, (long)bytes_written, strerror(errno));
- }
-
- return ret;
-}
-
-/*
- * Reset target_fname to "" in the two below functions for hibernation: if
- * the fcopy operation is aborted by hibernation, the daemon should remove the
- * partially-copied file; to achieve this, the hv_utils driver always fakes a
- * CANCEL_FCOPY message upon suspend, and later when the VM resumes back,
- * the daemon calls hv_copy_cancel() to remove the file; if a file is copied
- * successfully before suspend, hv_copy_finished() must reset target_fname to
- * avoid that the file can be incorrectly removed upon resume, since the faked
- * CANCEL_FCOPY message is spurious in this case.
- */
-static int hv_copy_finished(void)
-{
- close(target_fd);
- target_fname[0] = '\0';
- return 0;
-}
-static int hv_copy_cancel(void)
-{
- close(target_fd);
- if (strlen(target_fname) > 0) {
- unlink(target_fname);
- target_fname[0] = '\0';
- }
- return 0;
-
-}
-
-void print_usage(char *argv[])
-{
- fprintf(stderr, "Usage: %s [options]\n"
- "Options are:\n"
- " -n, --no-daemon stay in foreground, don't daemonize\n"
- " -h, --help print this help\n", argv[0]);
-}
-
-int main(int argc, char *argv[])
-{
- int fcopy_fd = -1;
- int error;
- int daemonize = 1, long_index = 0, opt;
- int version = FCOPY_CURRENT_VERSION;
- union {
- struct hv_fcopy_hdr hdr;
- struct hv_start_fcopy start;
- struct hv_do_fcopy copy;
- __u32 kernel_modver;
- } buffer = { };
- int in_handshake;
-
- static struct option long_options[] = {
- {"help", no_argument, 0, 'h' },
- {"no-daemon", no_argument, 0, 'n' },
- {0, 0, 0, 0 }
- };
-
- while ((opt = getopt_long(argc, argv, "hn", long_options,
- &long_index)) != -1) {
- switch (opt) {
- case 'n':
- daemonize = 0;
- break;
- case 'h':
- default:
- print_usage(argv);
- exit(EXIT_FAILURE);
- }
- }
-
- if (daemonize && daemon(1, 0)) {
- syslog(LOG_ERR, "daemon() failed; error: %s", strerror(errno));
- exit(EXIT_FAILURE);
- }
-
- openlog("HV_FCOPY", 0, LOG_USER);
- syslog(LOG_INFO, "starting; pid is:%d", getpid());
-
-reopen_fcopy_fd:
- if (fcopy_fd != -1)
- close(fcopy_fd);
- /* Remove any possible partially-copied file on error */
- hv_copy_cancel();
- in_handshake = 1;
- fcopy_fd = open("/dev/vmbus/hv_fcopy", O_RDWR);
-
- if (fcopy_fd < 0) {
- syslog(LOG_ERR, "open /dev/vmbus/hv_fcopy failed; error: %d %s",
- errno, strerror(errno));
- exit(EXIT_FAILURE);
- }
-
- /*
- * Register with the kernel.
- */
- if ((write(fcopy_fd, &version, sizeof(int))) != sizeof(int)) {
- syslog(LOG_ERR, "Registration failed: %s", strerror(errno));
- exit(EXIT_FAILURE);
- }
-
- while (1) {
- /*
- * In this loop we process fcopy messages after the
- * handshake is complete.
- */
- ssize_t len;
-
- len = pread(fcopy_fd, &buffer, sizeof(buffer), 0);
- if (len < 0) {
- syslog(LOG_ERR, "pread failed: %s", strerror(errno));
- goto reopen_fcopy_fd;
- }
-
- if (in_handshake) {
- if (len != sizeof(buffer.kernel_modver)) {
- syslog(LOG_ERR, "invalid version negotiation");
- exit(EXIT_FAILURE);
- }
- in_handshake = 0;
- syslog(LOG_INFO, "kernel module version: %u",
- buffer.kernel_modver);
- continue;
- }
-
- switch (buffer.hdr.operation) {
- case START_FILE_COPY:
- error = hv_start_fcopy(&buffer.start);
- break;
- case WRITE_TO_FILE:
- error = hv_copy_data(&buffer.copy);
- break;
- case COMPLETE_FCOPY:
- error = hv_copy_finished();
- break;
- case CANCEL_FCOPY:
- error = hv_copy_cancel();
- break;
-
- default:
- error = HV_E_FAIL;
- syslog(LOG_ERR, "Unknown operation: %d",
- buffer.hdr.operation);
-
- }
-
- /*
- * pwrite() may return an error due to the faked CANCEL_FCOPY
- * message upon hibernation. Ignore the error by resetting the
- * dev file, i.e. closing and re-opening it.
- */
- if (pwrite(fcopy_fd, &error, sizeof(int), 0) != sizeof(int)) {
- syslog(LOG_ERR, "pwrite failed: %s", strerror(errno));
- goto reopen_fcopy_fd;
- }
- }
-}
--
2.34.1