Project structure and IPC utilities

[PrasannaPaithankar]

This issue is regarding:

1. The cargo.toml workspace structure
Wouldn't it be better to

[workspace]
members = ["src/uu/*"]

instead of implicit workspace member declaration used currently.
Also the editions used across different members is different (2021 or 2024). Not a concern but consistency would be nice if possible.

2. smartcols re-implementation? [edit: can use crate tabled or uutils-term-grid]
libsmartcols is surely very stable and useful package. But has unsafe calls (which is not concerning though) and can be implemented very well in rust as it is a simple output formatter. Could be helpful when complexity of the project increases rather than just using wrappers.

3. POSIX IPC extension to lsipc
I am working on adding the options to view the POSIX mqueue (done), sem and shm to lsipc.
I had done similarly to the original util-linux early this year (see util-linux/util-linux#3382)
Will create a PR ASAP.

4. Include ipcrm, ipcmk
Also working on the same.

5. Drop tool ipcs
ipcs has been superseded by lsipc. Is the implementation required?

Given we are re-implementing things, I feel we should strongly rethink about structuring, even if the formatting and internal behavior shifts slightly given it meets the functionality.

Please let me know your opinions.

[PrasannaPaithankar]

For ipcrm cli options

current options

Options:
 -m, --shmem-id <id>           remove shared memory segment by id
 -M, --shmem-key <key>         remove shared memory segment by key
     --posix-shmem <name>      remove POSIX shared memory segment by name
 -q, --queue-id <id>           remove message queue by id
 -Q, --queue-key <key>         remove message queue by key
     --posix-mqueue <name>     remove POSIX message queue by name
 -s, --semaphore-id <id>       remove semaphore by id
 -S, --semaphore-key <key>     remove semaphore by key
     --posix-semaphore <name>  remove POSIX semaphore by name
 -a, --all[=shm|pshm|msg|pmsg|sem|psem]
                               remove all (in the specified category)
 -v, --verbose                 explain what is being done

 -h, --help                 display this help
 -V, --version              display version

ipcrm follows the Open Group requirements (https://pubs.opengroup.org/onlinepubs/7908799/xcu/ipcrm.html) which state:

If you change these tools please make sure it does not create a conflict
with the latest standard. For example, it is not recommended to add
short command line options before they are part of the standard.
Introducing new long options is acceptable.

The Single UNIX(TM) Specification, Version 2
Copyright (C) 1997 The Open Group

This is mentioned in https://github.com/util-linux/util-linux/blob/master/Documentation/howto-contribute.txt

Design Problem:

I feel it would be friendlier to keep options --id and --key so that I can allot lets say -m to sysv and -M to posix.
The issue is that it breaks the above requirement.

[PrasannaPaithankar]

Also just noticed #277 for reimplementation of smartcols.

[PrasannaPaithankar]

Also just noticed #277 for reimplementation of smartcols.

Can crate tabled (https://docs.rs/tabled/latest/tabled/) be a good alternative to smartcols?
@sylvestre