Re: [rfc] Fix PR 18208: update /proc/pid/coredump_filter by c code

[Luis Machado <lgustavo at codesourcery dot com>]

On 05/07/2015 07:44 AM, Luis Machado wrote:
> On 05/07/2015 06:05 AM, Yao Qi wrote:
> > Luis Machado <lgustavo@codesourcery.com> writes:
> >
> > > > > -# Get the inferior's PID.
> > > > > -set infpid ""
> > > > >    gdb_test_multiple "info inferiors" "getting inferior pid" {
> > > > > -    -re "process \($decimal\).*\r\n$gdb_prompt $" {
> > > > > -    set infpid $expect_out(1,string)
> > > > > +    -re "process $decimal.*\r\n$gdb_prompt $" {
> > > > >        }
> > > > >        -re "Remote target.*$gdb_prompt $" {
> > > > >        # If the target does not provide PID information (like
> > > > > usermode QEMU),
> > > >
> > > > This "If the target does not provide PID information" check sounds
> > > > odd now.  Do we still need it?
> > >
> > > If we're not dealing with PID's, i don't think so.
> >
> > At the very start, I removed this block, but I recall that this block is
> > used as a guard for usermode QEMU which doesn't provide PID
> > information.  With this patch applied, we'll access
> > /proc/self/coredump_filter, but I am afraid it doesn't work as expected
> > on usermode QEMU, because usermode QEMU just intercepts few /proc
> > accesses and pass most of them through the host linux.  Accessing
> > /proc/QEMU_PID/coredump_filter isn't what we want in this test, so I
> > think it's better to skip the test for usermode QEMU.
> >
> > Of course, I don't mind removing this block.  Luis, could you try this
> > patch and remove this block, see whether it causes fails on usermode
> > QEMU?
>
> Yeah, that sounds problematic. I'll give it a try and will let you know.

Removing that conditional block i get 14 FAIL's, so it doesn't look like 
this test is suited for usermode QEMU.

Besides that, without the conditional block i also see a problem with 
the existing testcase using coredump_var_addr as an array but declaring 
it as a regular variable. It causes a number of errors. Did you notice 
that? Maybe it is specific to a certain version of expect.

# Obtain the address of each variable that will be checked on each
# case.
set coredump_var_addr ""
foreach item $all_anon_corefiles {
    foreach name [list [lindex $item 3] [lindex $item 4]] {
        set test "print/x $name"
        gdb_test_multiple $test $test {
            -re " = \($hex\)\r\n$gdb_prompt $" {
                set coredump_var_addr($name) $expect_out(1,string)
            }
        }
    }
}