Isaac Dunham <ibid...@gmail.com> writes:
> On Wed, Jul 29, 2015 at 01:21:04PM +0100, Rainer Weikusat wrote:
>> Isaac Dunham <ibid...@gmail.com> writes:
>> > Or you can do it with mount, sudo, sh, and nlmon
>> > (http://git.r-36.net/nlmon).
>>
>> Using poll to wait for a message followed by recvmsg for reading it
>> offers (in absence of a timeout) no advantages over just doing a
>> blocking recv. Since this code neither uses control messages nor looks
>> at the returned flags, it can use recvfrom instead of the (more
>> complicated) recvmsg. Considering that it checks for message buffer
>> overflow via len >= sizeof(buf), the MSG_TRUNC flag should probably be
>> used to make the kernel return the real size in case a datagram was
>> truncated. Lastly, the message doesn't have to be copied to a 2nd buffer
>> just to turn the 0-terminated name=value pairs into \n-terminated ones.
>>
>> NB: I admit that I mainly did this because it looked like a nice, simple
>> programming task.
>
> A few comments:
> - I'm not the maintainer, and I don't see why this got sent here.
> - There's no reason to factor out print_event_if, and the code it replaced
> is clearer and more concise.
There's a very good reason to do that, namely, it's a separate task
working with its own set of variables, even in the orignal code. And
something which boasts of its light-weightness should keep rescanning
the same data over and over again just because that's what the standard
C library str*-functions will do when used naively or in situations
they're not well-suited for, eg
for (i = 0, olen = 0; i < len; i += slen + 1) {
slen = strlen(buf+i);
if (!slen || !strchr(buf+i, '='))
continue;
At this point, what would really be needed is a function which returns
a pointer to the next '=' or '\000' but C doesn't provide one.
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