Design question...


From: Jörgen Sigvardsson <jorgen.sigvardsson@kau.se>
Subject: Design question...
Date: Wed, 28 Feb 2001 12:27:02 +0100

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Hi!

Right now I'm cooking up a proc-entry for myself which allows for 
registration of signature keys. By registering a key you have to write 
something like this to my proc-entry:
- --->8----
AddRSAKey
CN=Jorgen Sigvardsson EM=jorgen.sigvardsson@kau.se
3
1234567
- --->8----

Basically it's a command specifier (1st line), an id line (typically an 
X.509-like name), an e-parameter for RSA (e-part of public key) and an 
n-parameter for RSA (n-part of public key).

I have implemented my own file operations[1]  for this proc entry which deals 
with reading[2] and writing to the proc file. Now here's the question:
Is it bad to require that the user process must do an atomic write per 
command? With atomic I mean write(fd, "AddRSAKey....", length). Right now I 
cannot handle stuff like: 
buf = "AddRSAKey...";
for(i = 0; i < strlen(buf); i++)
	write(fd, &buf[i], 1);
I don't want to go into parsing-orgies within the kernel.. ;)

write returns of course the length of what was "accepted", thus a chunk of 
several commands in the same buffer will be accepted IFF the user program is 
written correctly (i.e., it pays respect to what write() returns).

I think "weird" write semantics weighs heavier than utterly complex and error 
prone kernel code.. what do you guys think?


[1] proc_info is a nightmare for returning anything larger than 4k.. for a 
real code-mess, have a look at proc_file_read in fs/proc/generic.c

[2] reading returns a list of registered keys
- -- 
Jörgen Sigvardsson, B. Sc.
Lecturer, Computer Science Dept. Karlstad University
Tel: +46-(0)54-700 1786
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