snaputil

snapUtil.c

/*
 * Copyright 2017 Adam H. Leventhal. All Rights Reserved.
 */

#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>

#include <errno.h>
#include <sys/attr.h>
#include <sys/snapshot.h>


#define HAVE_OP_ROOT !defined(__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__)

#if HAVE_OP_ROOT
int fs_snapshot_root(int, const char *, uint32_t);
#endif

const char *g_pname;

void usage(void) {
	(void) fprintf(stderr, "Usage:\n");
	(void) fprintf(stderr, "\t%s -l <vol>\n", g_pname);
	(void) fprintf(stderr, "\t%s -c <snap> <vol>\n", g_pname);
	(void) fprintf(stderr, "\t%s -n <snap> <newname> <vol>\n", g_pname);
	(void) fprintf(stderr, "\t%s -d <snap> <vol>\n", g_pname);
	(void) fprintf(stderr, "\t%s -r <snap> <vol>\n", g_pname);
	(void) fprintf(stderr, "\t%s -s <snap> <vol> <mntpnt>\n", g_pname);
	(void) fprintf(stderr, "\t%s -u <snap> <vol>\n", g_pname);
#if HAVE_OP_ROOT
	(void) fprintf(stderr, "\t%s -R <snap> <vol> -- set rootfs to snapshot on next boot -- non-osx only\n", g_pname);
#endif
	exit(2);	
}

int do_create(const char *vol, const char *snap)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_create(dirfd, snap, 0);
	if (ret != 0)
		perror("fs_snapshot_create");
	return (ret);
}

int do_delete(const char *vol, const char *snap)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_delete(dirfd, snap, 0);
	if (ret != 0)
		perror("fs_snapshot_delete");
	return (ret);
}

int do_revert(const char *vol, const char *snap)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_revert(dirfd, snap, 0);
	if (ret != 0)
		perror("fs_snapshot_revert");
	return (ret);
}

int do_rename(const char *vol, const char *snap, const char *nw)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_rename(dirfd, snap, nw, 0);
	if (ret != 0)
		perror("fs_snapshot_rename");
	return (ret);
}

#if HAVE_OP_ROOT
int do_root(const char *vol, const char *snap)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_root(dirfd, snap, 0);
	if (ret != 0)
		perror("fs_snapshot_root");
	return (ret);
}
#endif

int do_mount(const char *vol, const char *snap, const char *mntpnt)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	int ret = fs_snapshot_mount(dirfd, mntpnt, snap, 0);
	if (ret != 0) {
		perror("fs_snapshot_mount");
	} else {
		printf("mount_apfs: snapshot implicitly mounted readonly\n");
	}
	return (ret);
}

int do_list(const char *vol)
{
	int dirfd = open(vol, O_RDONLY, 0);
	if (dirfd < 0) {
		perror("open");
		exit(1);
	}

	struct attrlist alist = { 0 };
	char abuf[2048];

	alist.commonattr = ATTR_BULK_REQUIRED;

	int count = fs_snapshot_list(dirfd, &alist, &abuf[0], sizeof (abuf), 0);
	if (count < 0) {
		perror("fs_snapshot_list");
		exit(1);
	}

	char *p = &abuf[0];
	for (int i = 0; i < count; i++) {
		char *field = p;
		uint32_t len = *(uint32_t *)field;
		field += sizeof (uint32_t);
		attribute_set_t attrs = *(attribute_set_t *)field;
		field += sizeof (attribute_set_t);

		if (attrs.commonattr & ATTR_CMN_NAME) {
			attrreference_t ar = *(attrreference_t *)field;
			char *name = field + ar.attr_dataoffset;
			field += sizeof (attrreference_t);
			(void) printf("%s\n", name);
		}

		p += len;
	}

	return (0);
}

int main(int argc, char **argv)
{
	g_pname = strrchr(argv[0], '/') + 1;

	if (argc < 3 || argv[1][0] != '-' ||
	    argv[1][1] == '\0' || argv[1][2] != '\0') {
		usage();
	}

	switch (argv[1][1]) {
		case 'l':
			if (argc != 3)
				usage();
			return (do_list(argv[2]));
		case 'c':
			if (argc != 4)
				usage();
			return (do_create(argv[3], argv[2]));
		case 'd':
			if (argc != 4)
				usage();
			return (do_delete(argv[3], argv[2]));
		case 'n':
			if (argc != 5)
				usage();
			return (do_rename(argv[4], argv[2], argv[3]));
		case 's':
			if (argc != 5)
				usage();
			return (do_mount(argv[3], argv[2], argv[4]));
		case 'r':
			if (argc != 4)
				usage();
			return (do_revert(argv[3], argv[2]));
#if HAVE_OP_ROOT
		case 'R':
			if (argc != 4)
				usage();
			return (do_root(argv[3], argv[2]));
#endif
		default:
			usage();
	}

	return (0);
}