Problem with readline is its API. It's basically a bunch of
global variables with no clear dependencies between them. In this
specific case that I'm seeing: in interactive mode the
cmdComplete() causes instant crash of virsh/virt-admin:
==27999== Invalid write of size 1
==27999== at 0x516EF71: _rl_init_line_state (readline.c:742)
==27999== by 0x5170054: rl_initialize (readline.c:1192)
==27999== by 0x516E5E4: readline (readline.c:379)
==27999== by 0x1B7024: vshReadline (vsh.c:3048)
==27999== by 0x140DCF: main (virsh.c:905)
==27999== Address 0x0 is not stack'd, malloc'd or (recently) free'd
This is because readline keeps a copy of pointer to
rl_line_buffer and the moment cmdComplete() returns and readline
takes over, it accesses the copy which is now a dangling pointer.
To fix this, just keep the original state of rl_line_buffer and
restore it.
Fixes: 41400ac1dda55b817388a4050aa823051bda2e05
Fixes: a0e1ada63c0afdc2af3b9405cbf637d8bd28700c
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
f6ab0d5bdd