Fix: statedump handle oom case, handle errors

lttng_enumerate_file_descriptors should check the pointer returned by
__get_free_page() (check if NULL).

do_lttng_statedump should check the sub-function return values. For
lttng_enumerate_block_devices(), we allow -ENOSYS to continue (if not
implemented).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fix: statedump: check whether "files" is NULL, RCU semantic fix

We need to check if p->files is NULL before passing it to
files_fdtable(). Moreover, since the fdt is now protected by RCU, we
have to assume it can change between the read from
lttng_enumerate_task_fd() and the internal in-kernel read in
iterate_fd(). Therefore, move this rcu dereference into
lttng_dump_one_fd(), and perform the appropriate checks on max fds.

Fixes #799

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Version 2.5.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
sys_connect extended fields IP(v4/v6) dest addr + port

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
add info to sys_accept also

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
fix: represent ports in decimal instead of hex

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>