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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2022 Google, Inc. All Rights Reserved.
*
* Test program which uses the raw ext4 set_fsuuid ioctl directly.
* SYNOPSIS:
* $0 COMMAND MOUNT_POINT [UUID]
*
* COMMAND must be either "get" or "set".
* The UUID must be a 16 octet sequence represented as 32 hexadecimal digits in
* canonical textual representation, e.g. output from `uuidgen`.
*
*/
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <uuid/uuid.h>
#include <linux/fs.h>
struct fsuuid {
__u32 fsu_len;
__u32 fsu_flags;
__u8 fsu_uuid[];
};
#ifndef EXT4_IOC_GETFSUUID
#define EXT4_IOC_GETFSUUID _IOR('f', 44, struct fsuuid)
#endif
#ifndef EXT4_IOC_SETFSUUID
#define EXT4_IOC_SETFSUUID _IOW('f', 44, struct fsuuid)
#endif
int main(int argc, char **argv)
{
int error, fd;
struct fsuuid *fsuuid = NULL;
if (argc < 3) {
fprintf(stderr, "Invalid arguments\n");
return 1;
}
fd = open(argv[2], O_RDONLY);
if (!fd) {
perror(argv[2]);
return 1;
}
fsuuid = malloc(sizeof(*fsuuid) + sizeof(uuid_t));
if (!fsuuid) {
perror("malloc");
return 1;
}
fsuuid->fsu_len = sizeof(uuid_t);
fsuuid->fsu_flags = 0;
if (strcmp(argv[1], "get") == 0) {
uuid_t uuid;
char uuid_str[37];
if (ioctl(fd, EXT4_IOC_GETFSUUID, fsuuid)) {
fprintf(stderr, "%s while trying to get fs uuid\n",
strerror(errno));
return 1;
}
memcpy(&uuid, fsuuid->fsu_uuid, sizeof(uuid));
uuid_unparse(uuid, uuid_str);
printf("%s\n", uuid_str);
} else if (strcmp(argv[1], "set") == 0) {
uuid_t uuid;
if (argc != 4) {
fprintf(stderr, "UUID argument missing.\n");
return 1;
}
error = uuid_parse(argv[3], uuid);
if (error < 0) {
fprintf(stderr, "Invalid UUID. The UUID should be in "
"canonical format. Example: "
"8c628557-6987-42b2-ba16-b7cc79ddfb43\n");
return 1;
}
memcpy(&fsuuid->fsu_uuid, uuid, sizeof(uuid));
if (ioctl(fd, EXT4_IOC_SETFSUUID, fsuuid)) {
fprintf(stderr, "%s while trying to set fs uuid\n",
strerror(errno));
return 1;
}
} else {
fprintf(stderr, "Invalid command\n");
return 1;
}
return 0;
}
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