Fix: add missing VALGRIND ifdef checks and documentation

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: miscellaneous memory handling fixes

Issues found with Valgrind:

- Uninitialized memory sent through sendmsg,
- Uninitialized realloc memory,
- Erroneous pointer arithmetic in jul_list_events(),
- Memory leaks in kernel_consumer_add_channel(),
  kernel_consumer_add_metadata(),
- Memory leak (snapshot_destroy missing hash table cleanup),
- Uninitialized poll/epoll memory on realloc.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: scanf unbounded input

Awaiting a proper cleanup (introducing nscanf), do what we can to
validate the scanf input using its utterly broken API.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: consumerd errors on exit

- The LTTNG_CONSUMER_STOP command is not used by sessiond anymore, so
  deprecate it,
- Ensure that the normal teardown (with signal handler) does not trigger
  a health error in consumer daemon by distinguishing between errors and
  "should exit" with different lttng_consumer_poll_socket() return values.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Comments fix: lttngerr.h -> error.h (./Changelog:754)

Signed-off-by: Jonathan Rajotte <jonathan.r.julien@gmail.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: perror on index directory creation error

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: wrong condition on startup for low-activity streams

If we only received and sent one index, we should not be in the retry
condition.
The rstream->total_index_received == vstream->last_sent_index is checked
before.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: missing big endian conversion for one index field

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Revert "Fix: wrong condition on startup for low-activity streams"

This reverts commit d3aac146d0800fe9820d51e5b9fa52e7543c1237.

Acked-by: Julien Desfossez <julien.desfossez@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>