just because the latter returned a NULL - that may normally happen,
when the process is, for example, a kernel thread
procfs_getargv(): if the name is brackened in '(' and ')', just
return NULL immediately - the code in command() will DTRT
and the output will be same for procfs- and kvm- based lookup
in all cases
also process start time, process arguments and session leadership status.
The procfs fallback is also used when kvm_openfiles() completely fails
(e.g. when /dev/mem is not readable).
Solves PR 7772, though the final implementation is different.
fstatfs() on the open file to verify that no intruder has mounted
something on portions of /proc. This will catch, for instance,
"mount_null /tmp /proc/1378". We already do 5 syscalls per
process, so one more won't hurt :) ... and safety is better than
performance when ps is otherwise broken.
- Also added a few close()'s at early returns, to avoid chewing up fd's.
fallback method is used, as the results could be untrustworthy if an
intruder is present. It is highly likely that NetBSD-1.5 will have
an improved kvm interface for reading process information, at which
point this code can be garbage-collected. Also added a word to the
man page -x option description while I was here.
