Examining Shared Memory

[OldSchool]

Is there a way, short of writing my own program, to examine the "contents" of a shared memory segment.

I can see the segment with ipcs, but need to examine the data values

TIA

Scott

[A. Clay Stephenson]

Get a copy of this utility:

ftp://hprc.external.hp.com/sysadmin/programs/shminfo/

[A. Clay Stephenson · Accepted solution]

This link will probably work better since it includes the 9unsupp8 password.


ftp://contrib:9unsupp8@hprc.external.hp.com/sysadmin/programs/shminfo/

[Bill Hassell]

shminfo will show you the addresses of all the shared memory segments, but to actually display the contents of a segment, you'll need a program. As you might expect, there are pieces of information needed (from the program creating the segment) to allow access and to prevent unauthorized access from casual users.

[A. Clay Stephenson]

Bear in mind that another approach to actually examining shmem is using Perl. The functions shmget, shmctl, shmread, and shmwrite are all available --- which is rather amazing for a scripting language. One of the obvious problems with a utility that reads shared memory is that the data really only has meaning for its intended application. The data generally are non-textual. One approach would be to use shmread to read the entire contents of a shared memory segment and write it to a file. You would then use a standard utility like od to examine the file.

The other obvious "gotcha" is that shared memory segments created with IPC_PRIVATE will not be accessible by unrelated processes.

[OldSchool]

Thanks for all of the quick responses. Looks like perl might be the way to go.

Scott