/*
 * An implementation of the host initiated guest snapshot for Hyper-V.
 *
 *
 * Copyright (C) 2013, Microsoft, Inc.
 * Author : K. Y. Srinivasan <kys@microsoft.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.
 *
 */


#include <sys/types.h>
#include <sys/poll.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <stdio.h>
#include <mntent.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <linux/fs.h>
#include <linux/hyperv.h>
#include <syslog.h>
#include <getopt.h>

/* Don't use syslog() in the function since that can cause write to disk */
static int vss_do_freeze(char *dir, unsigned int cmd)
{
	int ret, fd = open(dir, O_RDONLY);

	if (fd < 0)
		return 1;

	ret = ioctl(fd, cmd, 0);

	/*
	 * If a partition is mounted more than once, only the first
	 * FREEZE/THAW can succeed and the later ones will get
	 * EBUSY/EINVAL respectively: there could be 2 cases:
	 * 1) a user may mount the same partition to differnt directories
	 *  by mistake or on purpose;
	 * 2) The subvolume of btrfs appears to have the same partition
	 * mounted more than once.
	 */
	if (ret) {
		if ((cmd == FIFREEZE && errno == EBUSY) ||
		    (cmd == FITHAW && errno == EINVAL)) {
			close(fd);
			return 0;
		}
	}

	close(fd);
	return !!ret;
}

static int vss_operate(int operation)
{
	char match[] = "/dev/";
	FILE *mounts;
	struct mntent *ent;
	char errdir[1024] = {0};
	unsigned int cmd;
	int error = 0, root_seen = 0, save_errno = 0;

	switch (operation) {
	case VSS_OP_FREEZE:
		cmd = FIFREEZE;
		break;
	case VSS_OP_THAW:
		cmd = FITHAW;
		break;
	default:
		return -1;
	}

	mounts = setmntent("/proc/mounts", "r");
	if (mounts == NULL)
		return -1;

	while ((ent = getmntent(mounts))) {
		if (strncmp(ent->mnt_fsname, match, strlen(match)))
			continue;
		if (hasmntopt(ent, MNTOPT_RO) != NULL)
			continue;
		if (strcmp(ent->mnt_type, "vfat") == 0)
			continue;
		if (strcmp(ent->mnt_dir, "/") == 0) {
			root_seen = 1;
			continue;
		}
		error |= vss_do_freeze(ent->mnt_dir, cmd);
		if (error && operation == VSS_OP_FREEZE)
			goto err;
	}

	endmntent(mounts);

	if (root_seen) {
		error |= vss_do_freeze("/", cmd);
		if (error && operation == VSS_OP_FREEZE)
			goto err;
	}

	goto out;
err:
	save_errno = errno;
	if (ent) {
		strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
		endmntent(mounts);
	}
	vss_operate(VSS_OP_THAW);
	/* Call syslog after we thaw all filesystems */
	if (ent)
		syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
		       errdir, save_errno, strerror(save_errno));
	else
		syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
		       strerror(save_errno));
out:
	return error;
}

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 vss_fd, len;
	int error;
	struct pollfd pfd;
	int	op;
	struct hv_vss_msg vss_msg[1];
	int daemonize = 1, long_index = 0, opt;
	int in_handshake = 1;
	__u32 kernel_modver;

	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))
		return 1;

	openlog("Hyper-V VSS", 0, LOG_USER);
	syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());

	vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
	if (vss_fd < 0) {
		syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
		       errno, strerror(errno));
		exit(EXIT_FAILURE);
	}
	/*
	 * Register ourselves with the kernel.
	 */
	vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;

	len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
	if (len < 0) {
		syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
		       errno, strerror(errno));
		close(vss_fd);
		exit(EXIT_FAILURE);
	}

	pfd.fd = vss_fd;

	while (1) {
		pfd.events = POLLIN;
		pfd.revents = 0;

		if (poll(&pfd, 1, -1) < 0) {
			syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
			if (errno == EINVAL) {
				close(vss_fd);
				exit(EXIT_FAILURE);
			}
			else
				continue;
		}

		len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));

		if (in_handshake) {
			if (len != sizeof(kernel_modver)) {
				syslog(LOG_ERR, "invalid version negotiation");
				exit(EXIT_FAILURE);
			}
			kernel_modver = *(__u32 *)vss_msg;
			in_handshake = 0;
			syslog(LOG_INFO, "VSS: kernel module version: %d",
			       kernel_modver);
			continue;
		}

		if (len != sizeof(struct hv_vss_msg)) {
			syslog(LOG_ERR, "read failed; error:%d %s",
			       errno, strerror(errno));
			close(vss_fd);
			return EXIT_FAILURE;
		}

		op = vss_msg->vss_hdr.operation;
		error =  HV_S_OK;

		switch (op) {
		case VSS_OP_FREEZE:
		case VSS_OP_THAW:
			error = vss_operate(op);
			syslog(LOG_INFO, "VSS: op=%s: %s\n",
				op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
				error ? "failed" : "succeeded");

			if (error) {
				error = HV_E_FAIL;
				syslog(LOG_ERR, "op=%d failed!", op);
				syslog(LOG_ERR, "report it with these files:");
				syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
			}
			break;
		case VSS_OP_HOT_BACKUP:
			syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
			break;
		default:
			syslog(LOG_ERR, "Illegal op:%d\n", op);
		}
		vss_msg->error = error;
		len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
		if (len != sizeof(struct hv_vss_msg)) {
			syslog(LOG_ERR, "write failed; error: %d %s", errno,
			       strerror(errno));
			exit(EXIT_FAILURE);
		}
	}

	close(vss_fd);
	exit(0);
}
diff</a>)</td></tr></table>
<div class='commit-subject'>Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip</div><div class='commit-msg'>Pull SMP hotplug update from Thomas Gleixner:
 "This contains a trivial typo fix and an extension to the core code for
  dynamically allocating states in the prepare stage.

  The extension is necessary right now because we need a proper way to
  unbreak LTTNG, which iscurrently non functional due to the removal of
  the notifiers. Surely it's out of tree, but it's widely used by
  distros.

  The simple solution would have been to reserve a state for LTTNG, but
  I'm not fond about unused crap in the kernel and the dynamic range,
  which we admittedly should have done right away, allows us to remove
  quite some of the hardcoded states, i.e. those which have no ordering
  requirements. So doing the right thing now is better than having an
  smaller intermediate solution which needs to be reworked anyway"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/hotplug: Provide dynamic range for prepare stage
  perf/x86/amd/ibs: Fix typo after cleanup state names in cpu/hotplug
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=ca92e6c7e6329029d7188487a5c32e86ef471977'>Diffstat</a> (limited to 'net/rxrpc/insecure.c')</div><table summary='diffstat' class='diffstat'>