How can I access file by inode on Linux

Question

is there any userspace API or third-party kernel module that can help to access file by inode on Linux?

I'm trying to implement something like:

int read_file_by_ino(int ino, int pos, int size, char* buf);
int write_file_by_ino(int ino, int pos, int size, const char* buf);
int readdir_by_ino(...);
int stat_by_ino(...);
...

The program is expected to run under root user, so there's no security requirement to do permission checking.

Answer 1

I found the question connected concerning similar topic here.

Summarizing, check out those commands:

• find /path/to/mountpoint -inum <inode number>
• sudo debugfs -R 'ncheck 393094' /dev/sdaX 2>/dev/null

Hope this helps you investigate further.

Answer 2

Not sure if I understood your problem correctly but:
You can start with "/" directory and proceed recursively (or any loop for that matter) with children. Compare the inode value with strcut stat.ino_t. Once you find it, open the path/file.

Answer 3

I don't know if there is an easier way or not but you can do this with bash. with ls -i command you can see the inodes too,

$ ls -i
11147622 file.txt

the first column is the inode number, the blow command shows the inodes in current directory

$ ls -i | awk {'print $1'}

so you need to check the inodes from / too all it's subdirectories until find it

ls -iR /

it shows all subdirectories and there files with there inode number

now you should start from / and use awk to or cut command to have the first column(inode number is in the first column) then compare it with the inode you want to find.