On Thu, 16 Sep 2021 17:43:27 +0000, Kenny McCormack wrote:
> In article <
yga8rzw...@akutech.de>, Ralf Fassel <
ral...@gmx.de> wrote:
> ...
>> type:[inode]
>>
>> For example, socket:[2248868] will be a socket and its
>> inode is 2248868. For sockets, that inode can be used to
>> find more information in one of the files under
>> /proc/net/.
>>
>>HTH
>
> It pretty much tells me things I already knew.
>
> What I'm looking for is "What can I do with this number?" You say it is an
> "inode" number, but I doubt it is matches to a file in the file system.
> I.e., you would do: find / -inum 123456 -ls
>
> Longer term, what I am really looking for is "Who is on the other end of
> this pipe?"
Sorry, but I don't think you will be able to answer that question directly.
Apparently, from reading /usr/src/linux/fs/pipe.c, Linux implements pipes
within a pseudo-filesystem called "pipefs". Those inode numbers refer to
inodes within this pseudo-filesystem.
According to Linux.org (among others),
"Pipefs is a unique virtual filesystem. This filesystem is mounted
inside the kernel rather than in the userspace. While most filesystems
are mounted under "/", PipeFS is mounted on "pipe:", making PipeFS its
own root (yes, a second root filesystem). This filesystem is one
superblock and cannot exceed that amount system-wide. The entry point
of this filesystem/second-root is the system-call "pipe()". Unlike
the other virtual/pseudo filesystems, this one cannot be viewed."
(
https://www.linux.org/threads/pipefs-sockfs-debugfs-and-securityfs.9638/)
So, those pipe inode numbers address inodes in a filesystem that is not
externalized to /any/ subtree of /. This makes it difficult to use userland
utilities (like find, for instance) on the pipefs, and thus makes analysis
of individual pipe pairs /very/ difficult.
IDK, but you /might/ be able to explicitly mount pipefs to some part of the
filesystem tree. I can't guarantee that this will work, nor can I speculate
on /if/ any userland utility would be able to access it to provide you with
the information you seek.
HTH
--
Lew Pitcher
"In Skills, We Trust"