[GitHub/LineageOS/android_kernel_motorola_exynos9610.git] / tools / hv / hv_vss_daemon.c

/*
 * 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 <sys/stat.h>
#include <sys/sysmacros.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/major.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;
	struct stat sb;
	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 (stat(ent->mnt_fsname, &sb) == -1)
			continue;
		if (S_ISBLK(sb.st_mode) && major(sb.st_rdev) == LOOP_MAJOR)
			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));

			if (op == VSS_OP_FREEZE)
				vss_operate(VSS_OP_THAW);
		}
	}

	close(vss_fd);
	exit(0);
}
Commit	Line	Data
96dd86fa S	1	/*
	2	* An implementation of the host initiated guest snapshot for Hyper-V.
	3	*
	4	*
	5	* Copyright (C) 2013, Microsoft, Inc.
	6	* Author : K. Y. Srinivasan <kys@microsoft.com>
	7	*
	8	* This program is free software; you can redistribute it and/or modify it
	9	* under the terms of the GNU General Public License version 2 as published
	10	* by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful, but
	13	* WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
	15	* NON INFRINGEMENT. See the GNU General Public License for more
	16	* details.
	17	*
	18	*/
	19
	20
	21	#include <sys/types.h>
96dd86fa	22	#include <sys/poll.h>
7b413b65	23	#include <sys/ioctl.h>
ea81fdf0	24	#include <sys/stat.h>
f0078d20	25	#include <sys/sysmacros.h>
7b413b65	26	#include <fcntl.h>
96dd86fa	27	#include <stdio.h>
d3d1ee3a	28	#include <mntent.h>
96dd86fa S	29	#include <stdlib.h>
	30	#include <unistd.h>
	31	#include <string.h>
	32	#include <ctype.h>
	33	#include <errno.h>
7b413b65	34	#include <linux/fs.h>
ea81fdf0	35	#include <linux/major.h>
96dd86fa	36	#include <linux/hyperv.h>
96dd86fa	37	#include <syslog.h>
170f4bea	38	#include <getopt.h>
96dd86fa	39
4f689190 DC	40	/* Don't use syslog() in the function since that can cause write to disk */
4f689190 DC	41	static int vss_do_freeze(char *dir, unsigned int cmd)
7b413b65 OH	42	{
	43	int ret, fd = open(dir, O_RDONLY);
	44
	45	if (fd < 0)
	46	return 1;
4f689190	47
7b413b65	48	ret = ioctl(fd, cmd, 0);
4f689190 DC	49
	50	/*
	51	* If a partition is mounted more than once, only the first
	52	* FREEZE/THAW can succeed and the later ones will get
	53	* EBUSY/EINVAL respectively: there could be 2 cases:
	54	* 1) a user may mount the same partition to differnt directories
	55	* by mistake or on purpose;
	56	* 2) The subvolume of btrfs appears to have the same partition
	57	* mounted more than once.
	58	*/
	59	if (ret) {
	60	if ((cmd == FIFREEZE && errno == EBUSY) \|\|
	61	(cmd == FITHAW && errno == EINVAL)) {
	62	close(fd);
	63	return 0;
	64	}
	65	}
	66
7b413b65 OH	67	close(fd);
	68	return !!ret;
	69	}
	70
96dd86fa S	71	static int vss_operate(int operation)
96dd86fa S	72	{
d3d1ee3a OH	73	char match[] = "/dev/";
	74	FILE *mounts;
	75	struct mntent *ent;
ea81fdf0	76	struct stat sb;
4ce50e94	77	char errdir[1024] = {0};
7b413b65	78	unsigned int cmd;
7a401744	79	int error = 0, root_seen = 0, save_errno = 0;
96dd86fa S	80
	81	switch (operation) {
	82	case VSS_OP_FREEZE:
7b413b65	83	cmd = FIFREEZE;
96dd86fa S	84	break;
96dd86fa S	85	case VSS_OP_THAW:
7b413b65	86	cmd = FITHAW;
96dd86fa	87	break;
eb8905b8 OH	88	default:
eb8905b8 OH	89	return -1;
96dd86fa S	90	}
96dd86fa S	91
d3d1ee3a OH	92	mounts = setmntent("/proc/mounts", "r");
d3d1ee3a OH	93	if (mounts == NULL)
eb8905b8	94	return -1;
96dd86fa	95
0e272639	96	while ((ent = getmntent(mounts))) {
d3d1ee3a	97	if (strncmp(ent->mnt_fsname, match, strlen(match)))
96dd86fa	98	continue;
ea81fdf0 AN	99	if (stat(ent->mnt_fsname, &sb) == -1)
	100	continue;
	101	if (S_ISBLK(sb.st_mode) && major(sb.st_rdev) == LOOP_MAJOR)
	102	continue;
9e5db05a	103	if (hasmntopt(ent, MNTOPT_RO) != NULL)
10b637b4	104	continue;
f33b2155 S	105	if (strcmp(ent->mnt_type, "vfat") == 0)
f33b2155 S	106	continue;
d3d1ee3a OH	107	if (strcmp(ent->mnt_dir, "/") == 0) {
	108	root_seen = 1;
	109	continue;
	110	}
4f689190 DC	111	error \|= vss_do_freeze(ent->mnt_dir, cmd);
	112	if (error && operation == VSS_OP_FREEZE)
	113	goto err;
96dd86fa	114	}
96dd86fa	115
4ce50e94 VC	116	endmntent(mounts);
4ce50e94 VC	117
d3d1ee3a	118	if (root_seen) {
4f689190 DC	119	error \|= vss_do_freeze("/", cmd);
	120	if (error && operation == VSS_OP_FREEZE)
	121	goto err;
d3d1ee3a	122	}
96dd86fa	123
7a401744	124	goto out;
4f689190	125	err:
7a401744	126	save_errno = errno;
4ce50e94 VC	127	if (ent) {
	128	strncpy(errdir, ent->mnt_dir, sizeof(errdir)-1);
	129	endmntent(mounts);
	130	}
4f689190	131	vss_operate(VSS_OP_THAW);
7a401744 VK	132	/* Call syslog after we thaw all filesystems */
	133	if (ent)
	134	syslog(LOG_ERR, "FREEZE of %s failed; error:%d %s",
4ce50e94	135	errdir, save_errno, strerror(save_errno));
7a401744 VK	136	else
	137	syslog(LOG_ERR, "FREEZE of / failed; error:%d %s", save_errno,
	138	strerror(save_errno));
	139	out:
96dd86fa S	140	return error;
	141	}
	142
170f4bea VK	143	void print_usage(char *argv[])
	144	{
	145	fprintf(stderr, "Usage: %s [options]\n"
	146	"Options are:\n"
	147	" -n, --no-daemon stay in foreground, don't daemonize\n"
	148	" -h, --help print this help\n", argv[0]);
	149	}
	150
	151	int main(int argc, char *argv[])
96dd86fa	152	{
f5722b9b	153	int vss_fd, len;
96dd86fa	154	int error;
96dd86fa	155	struct pollfd pfd;
96dd86fa	156	int op;
f5722b9b	157	struct hv_vss_msg vss_msg[1];
170f4bea	158	int daemonize = 1, long_index = 0, opt;
cd8dc054 VK	159	int in_handshake = 1;
cd8dc054 VK	160	__u32 kernel_modver;
170f4bea VK	161
	162	static struct option long_options[] = {
	163	{"help", no_argument, 0, 'h' },
	164	{"no-daemon", no_argument, 0, 'n' },
	165	{0, 0, 0, 0 }
	166	};
	167
	168	while ((opt = getopt_long(argc, argv, "hn", long_options,
	169	&long_index)) != -1) {
	170	switch (opt) {
	171	case 'n':
	172	daemonize = 0;
	173	break;
	174	case 'h':
	175	default:
	176	print_usage(argv);
	177	exit(EXIT_FAILURE);
	178	}
	179	}
96dd86fa	180
170f4bea	181	if (daemonize && daemon(1, 0))
eb8905b8 OH	182	return 1;
eb8905b8 OH	183
96dd86fa S	184	openlog("Hyper-V VSS", 0, LOG_USER);
	185	syslog(LOG_INFO, "VSS starting; pid is:%d", getpid());
	186
f5722b9b VK	187	vss_fd = open("/dev/vmbus/hv_vss", O_RDWR);
	188	if (vss_fd < 0) {
	189	syslog(LOG_ERR, "open /dev/vmbus/hv_vss failed; error: %d %s",
	190	errno, strerror(errno));
d12e1469 TH	191	exit(EXIT_FAILURE);
d12e1469 TH	192	}
96dd86fa S	193	/*
	194	* Register ourselves with the kernel.
	195	*/
f5722b9b	196	vss_msg->vss_hdr.operation = VSS_OP_REGISTER1;
96dd86fa	197
f5722b9b	198	len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
96dd86fa	199	if (len < 0) {
f5722b9b VK	200	syslog(LOG_ERR, "registration to kernel failed; error: %d %s",
	201	errno, strerror(errno));
	202	close(vss_fd);
96dd86fa S	203	exit(EXIT_FAILURE);
	204	}
	205
f5722b9b	206	pfd.fd = vss_fd;
96dd86fa S	207
96dd86fa S	208	while (1) {
96dd86fa S	209	pfd.events = POLLIN;
96dd86fa S	210	pfd.revents = 0;
9561d479 TH	211
	212	if (poll(&pfd, 1, -1) < 0) {
	213	syslog(LOG_ERR, "poll failed; error:%d %s", errno, strerror(errno));
	214	if (errno == EINVAL) {
f5722b9b	215	close(vss_fd);
9561d479 TH	216	exit(EXIT_FAILURE);
	217	}
	218	else
	219	continue;
	220	}
96dd86fa	221
f5722b9b	222	len = read(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
96dd86fa	223
cd8dc054 VK	224	if (in_handshake) {
	225	if (len != sizeof(kernel_modver)) {
	226	syslog(LOG_ERR, "invalid version negotiation");
	227	exit(EXIT_FAILURE);
	228	}
	229	kernel_modver = (__u32 )vss_msg;
	230	in_handshake = 0;
	231	syslog(LOG_INFO, "VSS: kernel module version: %d",
	232	kernel_modver);
	233	continue;
	234	}
	235
f5722b9b VK	236	if (len != sizeof(struct hv_vss_msg)) {
	237	syslog(LOG_ERR, "read failed; error:%d %s",
	238	errno, strerror(errno));
	239	close(vss_fd);
	240	return EXIT_FAILURE;
5edf5ee4 OH	241	}
5edf5ee4 OH	242
96dd86fa S	243	op = vss_msg->vss_hdr.operation;
	244	error = HV_S_OK;
	245
	246	switch (op) {
	247	case VSS_OP_FREEZE:
	248	case VSS_OP_THAW:
	249	error = vss_operate(op);
4f689190 DC	250	syslog(LOG_INFO, "VSS: op=%s: %s\n",
	251	op == VSS_OP_FREEZE ? "FREEZE" : "THAW",
	252	error ? "failed" : "succeeded");
	253
	254	if (error) {
96dd86fa	255	error = HV_E_FAIL;
4f689190 DC	256	syslog(LOG_ERR, "op=%d failed!", op);
	257	syslog(LOG_ERR, "report it with these files:");
	258	syslog(LOG_ERR, "/etc/fstab and /proc/mounts");
	259	}
96dd86fa	260	break;
db886e4d AN	261	case VSS_OP_HOT_BACKUP:
	262	syslog(LOG_INFO, "VSS: op=CHECK HOT BACKUP\n");
	263	break;
96dd86fa S	264	default:
	265	syslog(LOG_ERR, "Illegal op:%d\n", op);
	266	}
	267	vss_msg->error = error;
a689d251	268	len = write(vss_fd, vss_msg, sizeof(struct hv_vss_msg));
f5722b9b VK	269	if (len != sizeof(struct hv_vss_msg)) {
	270	syslog(LOG_ERR, "write failed; error: %d %s", errno,
	271	strerror(errno));
6113e3d2 AN	272
	273	if (op == VSS_OP_FREEZE)
	274	vss_operate(VSS_OP_THAW);
96dd86fa S	275	}
	276	}
	277
f5722b9b VK	278	close(vss_fd);
f5722b9b VK	279	exit(0);
96dd86fa	280	}