/*
git clone https://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs.git
cd btrfs-progs
make
gcc -O2 -luuid -o uu send-utils.o rbtree.o btrfs-list.o /path/to/this/file/uu.c
*/

#define _GNU_SOURCE

#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <uuid/uuid.h>
#include <sys/ioctl.h>

#include "ctree.h"
#include "ioctl.h"
#include "send-utils.h"

#define CLEAR(var) memset(&var, 0, sizeof(var))


int main(int argc, char **argv) {
	int ret, fd;
	struct subvol_uuid_search sus;
	struct btrfs_ioctl_received_subvol_args rs_args;
	struct subvol_info *si;
	char uuidbuf[37], parent_uuidbuf[37], received_uuidbuf[37];


	if (argc != 3 && argc != 4) {
		printf("usage: uu srcmnt srcsub_reltosrcmnt [dstsub_abs]\n");
		exit(1);
	}

	printf("opening srcmnt %s\n", argv[1]);
	fd = open(argv[1], O_RDONLY | O_NOATIME);
	if (fd < 0) {
		printf("failed to open srcmnt %s! %s\n", argv[1], strerror(errno));
		exit(2);
	}

	puts("initializing sub search");
	CLEAR(sus);
	ret = subvol_uuid_search_init(fd, &sus);
	if (ret < 0) {
		printf("failed to initialize sub search! %s\n", strerror(-ret));
		exit(3);
	}
	
	printf("searching srcsub %s\n", argv[2]);
	si = subvol_uuid_search(&sus, 0, NULL, 0, argv[2], subvol_search_by_path);
	if (!si) {
		puts("srcsub not found!");
		exit(4);
	}

	uuid_unparse(si->uuid,                   uuidbuf);
	uuid_unparse(si->parent_uuid,     parent_uuidbuf);
	uuid_unparse(si->received_uuid, received_uuidbuf);

	printf("\nsrcsub found:\n"
	       "         uuid=%s\n"
	       "  parent_uuid=%s\n"
	       "received_uuid=%s\n"
	       "ctransid=%Lu otransid=%Lu stransid=%Lu rtransid=%Lu\n\n",
	       uuidbuf, parent_uuidbuf, received_uuidbuf,
	       (unsigned long long)(si->ctransid),
	       (unsigned long long)(si->otransid),
	       (unsigned long long)(si->stransid),
	       (unsigned long long)(si->rtransid));

	if (argc == 3)
		goto done;

	printf("opening dst subvol %s\n", argv[3]);
	fd = open(argv[3], O_RDONLY | O_NOATIME);
	if (fd < 0) {
		printf("failed to open dst subvol %s. %s\n", argv[3], strerror(errno));
		exit(5);
	}

	printf("\nhere we go with BTRFS_IOC_SET_RECEIVED_SUBVOL:\n"
	       "dstsub.received_uuid = srcsub.uuid == %s\n"
	       "dstsub.stransid = srcsub.ctransid == %Lu\n\n",
	       uuidbuf, (unsigned long long)(si->ctransid));

	CLEAR(rs_args);
	memcpy(rs_args.uuid, si->uuid, BTRFS_UUID_SIZE);
	rs_args.stransid = si->ctransid;

	ret = ioctl(fd, BTRFS_IOC_SET_RECEIVED_SUBVOL, &rs_args);
	if (ret < 0) {
		printf("BTRFS_IOC_SET_RECEIVED_SUBVOL failed: %s", strerror(-ret));
		exit(6);
	}

done:
	printf("done.\n");
	exit(0);
}