#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <stropts.h>
#include <poll.h>
#include <string.h>
#include <sys/fs/zev.h>
#include <errno.h>

#define OP_STATISTICS		(1 << 0)
#define OP_POLL_EVENTS		(1 << 1)
#define OP_MUTE_POOL		(1 << 2)
#define OP_UNMUTE_POOL		(1 << 3)
#define OP_SET_MAX_QUEUE_LEN	(1 << 4)

#define ZEV_DEVICE "/devices/pseudo/zev@0:zev"

static char *zev_device = ZEV_DEVICE;

static char *zev_op_name[] = {
	"ZEV_OP_ERROR",
	"ZEV_OP_MARK",
	"ZEV_OP_ZFS_MOUNT",
	"ZEV_OP_ZFS_UMOUNT",
	"ZEV_OP_ZVOL_WRITE",
	"ZEV_OP_ZVOL_TRUNCATE",
	"ZEV_OP_ZNODE_CLOSE_AFTER_UPDATE",
	"ZEV_OP_ZNODE_CREATE",
	"ZEV_OP_ZNODE_MKDIR",
	"ZEV_OP_ZNODE_MAKE_XATTR_DIR",
	"ZEV_OP_ZNODE_REMOVE",
	"ZEV_OP_ZNODE_RMDIR",
	"ZEV_OP_ZNODE_LINK",
	"ZEV_OP_ZNODE_SYMLINK",
	"ZEV_OP_ZNODE_RENAME",
	"ZEV_OP_ZNODE_WRITE",
	"ZEV_OP_ZNODE_TRUNCATE",
	"ZEV_OP_ZNODE_SETATTR",
	"ZEV_OP_ZNODE_ACL",
	NULL
};

static void
zev_statistics(int fd)
{
	zev_statistics_t zs;
	if (ioctl(fd, ZEV_IOC_GET_STATISTICS, &zs)) {
		perror("getting statistics data failed");
		exit (EXIT_FAILURE);
	}
	printf("ZEV module state:\n");

	printf("    queue length in bytes   : %lu\n", zs.zev_queue_len);
	printf("    queue length limit      : %lu\n", zs.zev_max_queue_len);
	printf("    poll wakeup throttle    : %lu\n\n",
	    zs.zev_poll_wakeup_queue_len);
	printf("    bytes read from device  : %lu\n", zs.zev_bytes_read);
	printf("    module internal errors  : %lu\n\n", zs.zev_cnt_errors);

	printf("ZFS event statistics:\n");

	printf("    total ZFS events        : %lu\n", zs.zev_cnt_total_events);
	printf("    ZFS mount               : %lu\n", zs.zev_cnt_zfs_mount);
	printf("    ZFS umount              : %lu\n", zs.zev_cnt_zfs_umount);
	printf("    ZVOL write              : %lu\n", zs.zev_cnt_zvol_write);
	printf("    ZVOL truncate           : %lu\n", zs.zev_cnt_zvol_truncate);
	printf("    ZNODE close after update: %lu\n",
	    zs.zev_cnt_znode_close_after_update);
	printf("    ZNODE create            : %lu\n", zs.zev_cnt_znode_create);
	printf("    ZNODE remove            : %lu\n", zs.zev_cnt_znode_remove);
	printf("    ZNODE link              : %lu\n", zs.zev_cnt_znode_link);
	printf("    ZNODE symlink           : %lu\n", zs.zev_cnt_znode_symlink);
	printf("    ZNODE rename            : %lu\n", zs.zev_cnt_znode_rename);
	printf("    ZNODE write             : %lu\n", zs.zev_cnt_znode_write);
	printf("    ZNODE truncate          : %lu\n",
	    zs.zev_cnt_znode_truncate);
	printf("    ZNODE setattr           : %lu\n", zs.zev_cnt_znode_setattr);
	printf("    ZNODE acl               : %lu\n", zs.zev_cnt_znode_acl);
}

static void
zev_print_error(char *buf)
{
	zev_error_t *rec = (zev_error_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: failed_op=%s msg=%s\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       zev_op_name[rec->failed_op - ZEV_OP_MIN], ZEV_ERRSTR(rec));
}

static void
zev_print_mark(char *buf)
{
	zev_mark_t *rec = (zev_mark_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu mark_id=%lld payload_len=%ld\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN], rec->guid, rec->mark_id,
	       rec->payload_len);
}

static void
zev_print_zfs_mount(char *buf)
{
	zev_zfs_mount_t *rec = (zev_zfs_mount_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu remount=%s dataset='%s' mountpoint='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid,
	       rec->remount ? "true" : "false",
	       ZEV_DATASET(rec),
	       ZEV_MOUNTPOINT(rec));
}

static void
zev_print_zfs_umount(char *buf)
{
	zev_zfs_umount_t *rec = (zev_zfs_umount_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid);
}

static void
zev_print_zvol_truncate(char *buf)
{
	zev_zvol_truncate_t *rec = (zev_zvol_truncate_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu offset=%llu length=%llu\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid,
	       rec->offset,
	       rec->length);
}

static void
zev_print_zvol_write(char *buf)
{
	zev_print_zvol_truncate(buf);
}

static void
zev_print_znode_close_after_update(char *buf)
{
	zev_znode_close_after_update_t *rec =
	    (zev_znode_close_after_update_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu file=%llu.%llu\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid,
	       rec->file.ino, rec->file.gen);
}

static void
zev_print_znode_create(char *buf)
{
	zev_znode_create_t *rec = (zev_znode_create_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu parent=%llu.%llu file=%llu.%llu "
	       "file.mtime=%llu, parent.mtime=%llu, name='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid,
	       rec->parent.ino, rec->parent.gen,
	       rec->file.ino, rec->file.gen,
	       rec->file.mtime, rec->parent.mtime,
	       ZEV_NAME(rec));
}

static void
zev_print_znode_mkdir(char *buf)
{
	zev_print_znode_create(buf);
}

static void
zev_print_znode_make_xattr_dir(char *buf)
{
	zev_print_znode_create(buf);
}

static void
zev_print_znode_remove(char *buf)
{
	zev_znode_remove_t *rec = (zev_znode_remove_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: guid=%llu parent=%llu.%llu file.mtime=%llu name='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->guid,
	       rec->parent.ino, rec->parent.gen,
	       rec->file.mtime,
	       ZEV_NAME(rec));
}

static void
zev_print_znode_rmdir(char *buf)
{
	zev_print_znode_remove(buf);
}

static void
zev_print_znode_link(char *buf)
{
	zev_znode_link_t *rec = (zev_znode_link_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: parent=%llu.%llu file=%llu.%llu "
	       "file.ctime=%llu parent.ctime=%llu name='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->parent.ino, rec->parent.gen,
	       rec->file.ino, rec->file.gen,
	       rec->file.ctime, rec->parent.ctime,
	       ZEV_NAME(rec));
	printf("links: %d\n", rec->file.links);
}

static void
zev_print_znode_symlink(char *buf)
{
	zev_znode_symlink_t *rec = (zev_znode_symlink_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: parent=%llu.%llu file=%llu.%llu name='%s' link='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->parent.ino, rec->parent.gen,
	       rec->file.ino, rec->file.gen,
	       ZEV_NAME(rec),
	       ZEV_LINK(rec));
}

static void
zev_print_znode_rename(char *buf)
{
	zev_znode_rename_t *rec = (zev_znode_rename_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: srcdir=%llu.%llu dstdir=%llu.%llu file=%llu.%llu "
	       "file.mtime=%llu, file.ctime=%llu, srcdir.mtime=%llu, "
	       "srcdir.ctime=%llu, dstdir.mtime=%llu, dstdir.ctime=%llu, "
	       "srcname='%s' dstname='%s'\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->srcdir.ino, rec->srcdir.gen,
	       rec->dstdir.ino, rec->dstdir.gen,
	       rec->file.ino, rec->file.gen,
	       rec->file.mtime, rec->file.ctime,
	       rec->srcdir.mtime, rec->srcdir.ctime,
	       rec->dstdir.mtime, rec->dstdir.ctime,
	       ZEV_SRCNAME(rec),
	       ZEV_DSTNAME(rec));
}

static void
zev_print_znode_write(char *buf)
{
	zev_znode_write_t *rec = (zev_znode_write_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: file=%llu.%llu offset=%llu length=%llu\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->file.ino, rec->file.gen,
	       rec->offset, rec->length);
}

static void
zev_print_znode_truncate(char *buf)
{
	zev_print_znode_write(buf);
}

static void
zev_print_znode_setattr(char *buf)
{
	zev_znode_setattr_t *rec = (zev_znode_setattr_t *)buf;
	time_t op_time = rec->op_time;
	char *ct = ctime(&op_time); ct[24] = '\0';

	printf("%s %s: file=%llu.%llu mtime=%llu\n",
	       ct, zev_op_name[rec->op - ZEV_OP_MIN],
	       rec->file.ino, rec->file.gen, rec->file.mtime);
}

static void
zev_print_znode_acl(char *buf)
{
	zev_print_znode_setattr(buf);
}

static void
zev_print_event(char *buf, int len)
{
	int record_len;
	int op;

	record_len = *(uint32_t *)buf;
	if (record_len != len) {
		fprintf(stderr, "record length mismatch: got %d, expected %d\n",
		        record_len, len);
		exit(1);
	}
	op = *((uint32_t *)buf + 1);
	if (op < ZEV_OP_MIN || op > ZEV_OP_MAX) {
		fprintf(stderr, "unknown op code: %d\n", op);
		exit(1);
	}
	switch (op) {
	case ZEV_OP_ERROR:
		zev_print_error(buf);
		break;
	case ZEV_OP_MARK:
		zev_print_mark(buf);
		break;
	case ZEV_OP_ZFS_MOUNT:
		zev_print_zfs_mount(buf);
		break;
	case ZEV_OP_ZFS_UMOUNT:
		zev_print_zfs_umount(buf);
		break;
	case ZEV_OP_ZVOL_TRUNCATE:
		zev_print_zvol_truncate(buf);
		break;
	case ZEV_OP_ZVOL_WRITE:
		zev_print_zvol_write(buf);
		break;
	case ZEV_OP_ZNODE_CLOSE_AFTER_UPDATE:
		zev_print_znode_close_after_update(buf);
		break;
	case ZEV_OP_ZNODE_CREATE:
		zev_print_znode_create(buf);
		break;
	case ZEV_OP_ZNODE_MKDIR:
		zev_print_znode_mkdir(buf);
		break;
	case ZEV_OP_ZNODE_MAKE_XATTR_DIR:
		zev_print_znode_make_xattr_dir(buf);
		break;
	case ZEV_OP_ZNODE_REMOVE:
		zev_print_znode_remove(buf);
		break;
	case ZEV_OP_ZNODE_RMDIR:
		zev_print_znode_rmdir(buf);
		break;
	case ZEV_OP_ZNODE_LINK:
		zev_print_znode_link(buf);
		break;
	case ZEV_OP_ZNODE_SYMLINK:
		zev_print_znode_symlink(buf);
		break;
	case ZEV_OP_ZNODE_RENAME:
		zev_print_znode_rename(buf);
		break;
	case ZEV_OP_ZNODE_WRITE:
		zev_print_znode_write(buf);
		break;
	case ZEV_OP_ZNODE_TRUNCATE:
		zev_print_znode_truncate(buf);
		break;
	case ZEV_OP_ZNODE_SETATTR:
		zev_print_znode_setattr(buf);
		break;
	case ZEV_OP_ZNODE_ACL:
		zev_print_znode_acl(buf);
		break;
	default:
		fprintf(stderr, "unhandled op code: %d\n", op);
		exit(1);
	}
}

static void
zev_poll_events(int fd)
{
	struct pollfd pfd[1];
	int ret;
	char buf[4096];
	zev_event_t	*ev;
	int off = 0;
	while (1) {
		pfd[0].fd = fd;
		pfd[0].events = POLLIN;
		ret = poll(pfd, 1, 1000);
		if (ret < 0) {
			perror("poll failed");
			exit(EXIT_FAILURE);
		}
		if (!(pfd[0].revents & POLLIN))
			continue;
		/* data available */
		ret = read(fd, buf, sizeof(buf));
		if (ret < 0) {
			perror("read failed");
			exit(EXIT_FAILURE);
		}
		if (ret == 0)
			continue;
		while (ret > off) {
			ev = (zev_event_t *)(buf + off);
			zev_print_event(buf + off, ev->header.record_len);
			off += ev->header.record_len;
		}
		off = 0;
	}
	return;
}

static void
usage(char *progname)
{
	fprintf(stderr, "usage: %s [-s] [-d <dev>]\n", progname);
	fprintf(stderr, "   -s         show zev statistics\n");
	fprintf(stderr, "   -p         poll for ZFS events\n");
	fprintf(stderr, "   -q <bytes> set maximum event queue length\n");
	fprintf(stderr, "   -t <bytes> set queue length poll throttle\n");
	fprintf(stderr, "   -m <pool>  mute pool, no events for this pool\n");
	fprintf(stderr, "   -M <pool>  unmute pool\n");
	fprintf(stderr, "   -d <dev>   device file to use. default is '%s'\n",
	    ZEV_DEVICE);
	fprintf(stderr, "   -k <guid>:<payload>   queue mark event\n");
	exit (EXIT_FAILURE);
}

static int
zev_set_max_queue_len(int fd, char *optarg)
{
	uint64_t maxqueuelen;

	errno = 0;
	maxqueuelen = strtol(optarg, (char **)NULL, 10);
	if (errno) {
		fprintf(stderr, "invalid queue length parameter: %s\n", optarg);
		return (EXIT_FAILURE);
	}
	if (ioctl(fd, ZEV_IOC_SET_MAX_QUEUE_LEN, &maxqueuelen)) {
		perror("setting max queue length failed");
		return (EXIT_FAILURE);
	}
	return (0);
}

static int
zev_set_poll_wakeup_queue_len(int fd, char *optarg)
{
	uint64_t queuelen;

	errno = 0;
	queuelen = strtol(optarg, (char **)NULL, 10);
	if (errno) {
		fprintf(stderr, "invalid queue length parameter: %s\n", optarg);
		return (EXIT_FAILURE);
	}
	if (ioctl(fd, ZEV_IOC_SET_POLL_WAKEUP_QUEUE_LEN, &queuelen)) {
		perror("setting poll wakeup queue length failed");
		return (EXIT_FAILURE);
	}
	return (0);
}

static int
zev_mute_unmute_impl(int fd, char *poolname, int mute)
{
	zev_ioctl_poolarg_t pa;
	int len;
	int op = mute ? ZEV_IOC_MUTE_POOL : ZEV_IOC_UNMUTE_POOL;
	len = strlen(poolname);
	if (len <= 0 || len >= sizeof(pa.zev_poolname)) {
		fprintf(stderr, "invalid poolname: %s\n", poolname);
		return (EXIT_FAILURE);
	}
	strcpy(pa.zev_poolname, poolname);
	pa.zev_poolname_len = len;
	if (ioctl(fd, op, &pa)) {
		perror("muting pool data failed");
		return (EXIT_FAILURE);
	}
	return (0);
}

int
zev_mute_pool(int fd, char *poolname)
{
	return zev_mute_unmute_impl(fd, poolname, 1);
}

int
zev_unmute_pool(int fd, char *poolname)
{
	return zev_mute_unmute_impl(fd, poolname, 0);
}

static int
zev_mark(int fd, char *arg)
{
	zev_ioctl_mark_t *mark;
	uint64_t guid;
	int len;
	char *p;

	p = strchr(arg, ':');
	if (!p) {
		fprintf(stderr, "expected value is <guid>:<payload>, "
		        "e.g. '123:hello'\n");
		exit (EXIT_FAILURE);
	}
	*p = '\n';
	p++;

	errno = 0;
	guid = strtoll(optarg, (char **)NULL, 10);
	if (errno) {
		fprintf(stderr, "guid must be a number.\n");
		exit (EXIT_FAILURE);
	}

	len = strlen(p);

	mark = malloc(sizeof(*mark) + len + 1);
	if (!mark) {
		fprintf(stderr, "can't allocate mark structure: %s\n",
		        strerror(errno));
		exit (EXIT_FAILURE);
	}
	mark->zev_guid = guid;
	mark->zev_mark_id = 0;
	mark->zev_payload_len = len;
	strcpy(ZEV_PAYLOAD(mark), p);

	if (ioctl(fd, ZEV_IOC_MARK, mark)) {
		perror("queueing mark failed");
		return (EXIT_FAILURE);
	}

	printf("mark id: %lu\n", mark->zev_mark_id);
	return (0);
}

int
main(int argc, char **argv)
{
	int fd;
	int c;
	int ops = 0;
	extern char *optarg;

	/* open device */
	fd = open(zev_device, O_RDONLY);
	if (fd < 0) {
		perror("opening zev device failed");
		return EXIT_FAILURE;
	}
	while ((c = getopt(argc, argv, "spdk:q:t:m:M:h?")) != -1) {
		switch(c) {
		case 's':
			ops |= OP_STATISTICS;
			break;
		case 'p':
			ops |= OP_POLL_EVENTS;
			break;
		case 'd':
			zev_device = optarg;
			break;
		case 'q':
			return zev_set_max_queue_len(fd, optarg);
		case 't':
			return zev_set_poll_wakeup_queue_len(fd, optarg);
		case 'm':
			return zev_mute_pool(fd, optarg);
		case 'M':
			return zev_unmute_pool(fd, optarg);
		case 'k':
			return zev_mark(fd, optarg);
		case 'h':
		case '?':
		default:
			usage(argv[0]);
		}
	}
	if (!ops)
		usage(argv[0]);
	if (ops & OP_STATISTICS)
		zev_statistics(fd);
	if (ops & OP_POLL_EVENTS)
		zev_poll_events(fd);
	close(fd);
	return EXIT_SUCCESS;
}