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mirror of git://sourceware.org/git/lvm2.git synced 2024-12-22 17:35:59 +03:00
lvm2/daemons/clogd/local.c
Jonathan Earl Brassow bf0378593c Initial import of the cluster log daemon from the 'cluster' repository.
There is a rudimentary make file in place so people can build by hand
from 'LVM2/daemons/clogd'.  It is not hooked into the main build system
yet.  I am checking this in to provide people better access to the
source code.

There is still work to be done to make better use of existing code in
the LVM repository.  (list.h could be removed in favor of existing list
implementations, for example.  Logging might also be removed in favor
of what is already in the tree.)

I will probably defer updating WHATS_NEW_DM until this code is linked
into the main build system (unless otherwise instructed).
2009-01-08 17:12:33 +00:00

380 lines
8.0 KiB
C

#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <stdint.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/poll.h>
#include <linux/connector.h>
#include <linux/netlink.h>
#include "linux/dm-clog-tfr.h"
#include "functions.h"
#include "cluster.h"
#include "common.h"
#include "logging.h"
#include "link_mon.h"
#include "local.h"
static int cn_fd; /* Connector (netlink) socket fd */
static char recv_buf[2048];
/* FIXME: merge this function with kernel_send_helper */
static int kernel_ack(uint32_t seq, int error)
{
int r;
unsigned char buf[sizeof(struct nlmsghdr) + sizeof(struct cn_msg)];
struct nlmsghdr *nlh = (struct nlmsghdr *)buf;
struct cn_msg *msg = NLMSG_DATA(nlh);
if (error < 0) {
LOG_ERROR("Programmer error: error codes must be positive");
return -EINVAL;
}
memset(buf, 0, sizeof(buf));
nlh->nlmsg_seq = 0;
nlh->nlmsg_pid = getpid();
nlh->nlmsg_type = NLMSG_DONE;
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(struct cn_msg));
nlh->nlmsg_flags = 0;
msg->len = 0;
msg->id.idx = 0x4;
msg->id.val = 0x1;
msg->seq = seq;
msg->ack = error;
r = send(cn_fd, nlh, NLMSG_LENGTH(sizeof(struct cn_msg)), 0);
/* FIXME: do better error processing */
if (r <= 0)
return -EBADE;
return 0;
}
/*
* kernel_recv
* @tfr: the newly allocated request from kernel
*
* Read requests from the kernel and allocate space for the new request.
* If there is no request from the kernel, *tfr is NULL.
*
* This function is not thread safe due to returned stack pointer. In fact,
* the returned pointer must not be in-use when this function is called again.
*
* Returns: 0 on success, -EXXX on error
*/
static int kernel_recv(struct clog_tfr **tfr)
{
int r = 0;
int len;
struct cn_msg *msg;
*tfr = NULL;
memset(recv_buf, 0, sizeof(recv_buf));
len = recv(cn_fd, recv_buf, sizeof(recv_buf), 0);
if (len < 0) {
LOG_ERROR("Failed to recv message from kernel");
r = -errno;
goto fail;
}
switch (((struct nlmsghdr *)recv_buf)->nlmsg_type) {
case NLMSG_ERROR:
LOG_ERROR("Unable to recv message from kernel: NLMSG_ERROR");
r = -EBADE;
goto fail;
case NLMSG_DONE:
msg = (struct cn_msg *)NLMSG_DATA((struct nlmsghdr *)recv_buf);
len -= sizeof(struct nlmsghdr);
if (len < sizeof(struct cn_msg)) {
LOG_ERROR("Incomplete request from kernel received");
r = -EBADE;
goto fail;
}
if (msg->len > DM_CLOG_TFR_SIZE) {
LOG_ERROR("Not enough space to receive kernel request (%d/%d)",
msg->len, DM_CLOG_TFR_SIZE);
r = -EBADE;
goto fail;
}
if (!msg->len)
LOG_ERROR("Zero length message received");
len -= sizeof(struct cn_msg);
if (len < msg->len)
LOG_ERROR("len = %d, msg->len = %d", len, msg->len);
msg->data[msg->len] = '\0'; /* Cleaner way to ensure this? */
*tfr = (struct clog_tfr *)msg->data;
if (!(*tfr)->request_type) {
LOG_DBG("Bad transmission, requesting resend [%u]", msg->seq);
r = -EAGAIN;
if (kernel_ack(msg->seq, EAGAIN)) {
LOG_ERROR("Failed to NACK kernel transmission [%u]",
msg->seq);
r = -EBADE;
}
}
break;
default:
LOG_ERROR("Unknown nlmsg_type");
r = -EBADE;
}
fail:
if (r)
*tfr = NULL;
return (r == -EAGAIN) ? 0 : r;
}
static int kernel_send_helper(void *data, int out_size)
{
int r;
struct nlmsghdr *nlh;
struct cn_msg *msg;
unsigned char buf[2048];
memset(buf, 0, sizeof(buf));
nlh = (struct nlmsghdr *)buf;
nlh->nlmsg_seq = 0; /* FIXME: Is this used? */
nlh->nlmsg_pid = getpid();
nlh->nlmsg_type = NLMSG_DONE;
nlh->nlmsg_len = NLMSG_LENGTH(out_size + sizeof(struct cn_msg));
nlh->nlmsg_flags = 0;
msg = NLMSG_DATA(nlh);
memcpy(msg->data, data, out_size);
msg->len = out_size;
msg->id.idx = 0x4;
msg->id.val = 0x1;
msg->seq = 0;
r = send(cn_fd, nlh, NLMSG_LENGTH(out_size + sizeof(struct cn_msg)), 0);
/* FIXME: do better error processing */
if (r <= 0)
return -EBADE;
return 0;
}
/*
* do_local_work
*
* Any processing errors are placed in the 'tfr'
* structure to be reported back to the kernel.
* It may be pointless for this function to
* return an int.
*
* Returns: 0 on success, -EXXX on failure
*/
static int do_local_work(void *data)
{
int r;
struct clog_tfr *tfr = NULL;
r = kernel_recv(&tfr);
if (r)
return r;
if (!tfr)
return 0;
LOG_DBG("[%s] Request from kernel received: [%s/%u]",
SHORT_UUID(tfr->uuid), RQ_TYPE(tfr->request_type),
tfr->seq);
switch (tfr->request_type) {
case DM_CLOG_CTR:
case DM_CLOG_DTR:
case DM_CLOG_IN_SYNC:
case DM_CLOG_GET_SYNC_COUNT:
case DM_CLOG_STATUS_INFO:
case DM_CLOG_STATUS_TABLE:
case DM_CLOG_PRESUSPEND:
/* We do not specify ourselves as server here */
r = do_request(tfr, 0);
if (r)
LOG_DBG("Returning failed request to kernel [%s]",
RQ_TYPE(tfr->request_type));
r = kernel_send(tfr);
if (r)
LOG_ERROR("Failed to respond to kernel [%s]",
RQ_TYPE(tfr->request_type));
break;
case DM_CLOG_RESUME:
/*
* Resume is a special case that requires a local
* component to join the CPG, and a cluster component
* to handle the request.
*/
r = local_resume(tfr);
if (r) {
LOG_DBG("Returning failed request to kernel [%s]",
RQ_TYPE(tfr->request_type));
r = kernel_send(tfr);
if (r)
LOG_ERROR("Failed to respond to kernel [%s]",
RQ_TYPE(tfr->request_type));
break;
}
/* ELSE, fall through */
case DM_CLOG_IS_CLEAN:
case DM_CLOG_FLUSH:
case DM_CLOG_MARK_REGION:
case DM_CLOG_GET_RESYNC_WORK:
case DM_CLOG_SET_REGION_SYNC:
case DM_CLOG_IS_REMOTE_RECOVERING:
case DM_CLOG_POSTSUSPEND:
r = cluster_send(tfr);
if (r) {
tfr->data_size = 0;
tfr->error = r;
kernel_send(tfr);
}
break;
case DM_CLOG_CLEAR_REGION:
r = kernel_ack(tfr->seq, 0);
r = cluster_send(tfr);
if (r) {
/*
* FIXME: store error for delivery on flush
* This would allow us to optimize MARK_REGION
* too.
*/
}
break;
case DM_CLOG_GET_REGION_SIZE:
default:
LOG_ERROR("Invalid log request received, ignoring.");
return 0;
}
if (r && !tfr->error)
tfr->error = r;
return r;
}
/*
* kernel_send
* @tfr: result to pass back to kernel
*
* This function returns the tfr structure
* (containing the results) to the kernel.
* It then frees the structure.
*
* WARNING: should the structure be freed if
* there is an error? I vote 'yes'. If the
* kernel doesn't get the response, it should
* resend the request.
*
* Returns: 0 on success, -EXXX on failure
*/
int kernel_send(struct clog_tfr *tfr)
{
int r;
int size;
if (!tfr)
return -EINVAL;
size = sizeof(struct clog_tfr) + tfr->data_size;
if (!tfr->data_size && !tfr->error) {
/* An ACK is all that is needed */
/* FIXME: add ACK code */
} else if (size > DM_CLOG_TFR_SIZE) {
/*
* If we gotten here, we've already overrun
* our allotted space somewhere.
*
* We must do something, because the kernel
* is waiting for a response.
*/
LOG_ERROR("Not enough space to respond to server");
tfr->error = -ENOSPC;
size = sizeof(struct clog_tfr);
}
r = kernel_send_helper(tfr, size);
if (r)
LOG_ERROR("Failed to send msg to kernel.");
return r;
}
/*
* init_local
*
* Initialize kernel communication socket (netlink)
*
* Returns: 0 on success, values from common.h on failure
*/
int init_local(void)
{
int r = 0;
int opt;
struct sockaddr_nl addr;
cn_fd = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_CONNECTOR);
if (cn_fd < 0)
return EXIT_KERNEL_TFR_SOCKET;
/* memset to fix valgrind complaint */
memset(&addr, 0, sizeof(struct sockaddr_nl));
addr.nl_family = AF_NETLINK;
addr.nl_groups = 0x4;
addr.nl_pid = 0;
r = bind(cn_fd, (struct sockaddr *) &addr, sizeof(addr));
if (r < 0) {
close(cn_fd);
return EXIT_KERNEL_TFR_BIND;
}
opt = addr.nl_groups;
r = setsockopt(cn_fd, 270, NETLINK_ADD_MEMBERSHIP, &opt, sizeof(opt));
if (r) {
close(cn_fd);
return EXIT_KERNEL_TFR_SETSOCKOPT;
}
/*
r = fcntl(cn_fd, F_SETFL, FNDELAY);
*/
links_register(cn_fd, "local", do_local_work, NULL);
return 0;
}
/*
* cleanup_local
*
* Clean up before exiting
*/
void cleanup_local(void)
{
links_unregister(cn_fd);
close(cn_fd);
}