Re: [RFC][PATCH] /proc/pid/maps doesn't match "ipcs -m" shmid

Albert Cahalan
2007-06-07T16:43:42Z

On 6/7/07, Badari Pulavarty <pbadari@us.ibm.com> wrote:

> BTW, I agree with Eric that its would be nice to use shmid as part
> of name instead of forcing to be as inode number. It should be
> possible for pmap to workout shmid from "key" or name. Isn't it ?

It is not at all nice.

1. it's incompatible ABI breakage
2. where will you put the key then, in the inode? :-)

Changing to "SYSVID%d" is no good either. Look, people
are ***parsing*** this stuff in /proc. The /proc filesystem
is not some random sandbox to be playing in.

Before you go messing with it, note that the device number
also matters. (it's per-boot dynamic, but that's OK)
That's how one knows that /SYSV00000000 is not just
a regular file; sadly these didn't get a non-/ prefix.
(and no you can't fix that now; it's way too late)

Next time you feel like breaking an ABI, mind putting
"LET'S BREAK AN ABI!" in the subject of your email?

BTW, I suspect this kind of thing also breaks:
a. fuser, lsof, and other resource usage display tools
b. various obscure emulators (similar to valgrind)