sessiond: introduce cleared_after_last_stop

Track whether a session was cleared after the last stop, so
additional clear will be effect-less until it is started again.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Icaa86acab20081b436bd55d026ec79a10c56034b
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: implement ust app clear session

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I9205b25cd18035156485df980104dea5c241542f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: implement kernel clear session

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ie47c128fc951b206c7ae50933395e9ade9d0012d
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: implement consumer clear channel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I1c17a34c23e4c03f94acb99fb822c3bc42faccf5
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

consumer: implement clear channel

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I4eefc1d23b1b781f055790933572c4796375da26
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common trace-chunk: introduce lttng_trace_chunk_get_name_overridden

While it is possible to query whether the name of a chunk is
overridden through lttng_trace_chunk_get_name(), using it requires
a lot of code to deal with an unused name string when all that is needed
is to check whether the name is overridden.

In preparation for the new "path" handling needed for the clear
feature introduce this lttng_trace_chunk_get_name_overridden()
API to allow checking whether name is overridden in a succint way.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ied8bcbb5202826e68a5d6b54130f29f203948794
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common: trace-chunk: track all files within a chunk

Track all files added/removed in a chunk. Required by the clear
feature so all files of a prior chunk can be unlinked, even if
they belong to applications which have already closed their
stream with per-pid UST buffers.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I41bf8ac61f9a8ed1e8f206520ef8845a102b1c1e
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: cmd_rotate_session: introduce command argument

Add a command type argument to cmd_rotate_session().

Change the internal session_close_trace_chunk() API to introduce the
LTTNG_TRACE_CHUNK_COMMAND_TYPE_NO_OPERATION command rather than rely on
a NULL pointer, which facilitates passing of command argument across
cmd_rotate_session.

This introduces the LTTNG_TRACE_CHUNK_COMMAND_TYPE_DELETE command,
which is required for the clear feature. Its implementation will
follow in a separate commit.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic1d8cbab1f98b93f1f6d27a2c6624ac2780932e2
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: query relayd configuration for availability of clear feature

Query the relayd configuration when connecting to check for availability
of the clear feature.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I5827fdc7f92bc9bc87ccf9d1c567057b2c227e2b
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd: Implement get_configuration relayd protocol command

Introduce a "GET_CONFIGURATION" command to the relayd protocol.
This allows checking whether the relay daemon allows the clear
command or not. A 64-bit set of flags are returned, and it can be
extended in the future with a variable length payload.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I33a03d09871f1c0c248d5514451c533ffd773979
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common: index and trace-chunk file creation/open API change

An API change to the common libraries is required for the following
functions to accomodate the clear feature:

- lttng_trace_chunk_open_file(),
- lttng_index_file_create_from_trace_chunk(),
- lttng_index_file_create_from_trace_chunk_read_only().

An "expect_no_file" boolean is introduced, allowing specific invocation
to consider a ENOENT errno as an expected condition (and not an error).
This is the case for instance for relayd live viewer_stream_rotate(),
which can fail to open files in the new chunk after a clear with per-pid
buffers. Same goes for viewer_get_next_index() and try_open_index().

Change the lttng_index_file_create_from_trace_chunk_read_only and
lttng_index_file_create_from_trace_chunk to allow them to return
a chunk status, which allows the callers to distinguish between
errors and a "no file" status, and deal with the situation accordingly.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3c43edca01629488c4e777078db7ffd2e88dc7ea
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common: index: remove redundant separator for empty channel string

Tweak _lttng_index_file_create_from_trace_chunk() to correctly deal with
empty channel_path string, removing redundant "/" separators.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I743917c27e334ad12e145959b3ad3f59f62f1a64
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: refactoring: introduce start/stop_kernel_session

The clear feature will need to stop kernel session as well, so move this
code to its own function rather than duplicate it.

start_kernel_session already exists, but is static. Expose it so it
can be used from a separate compile unit.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I68da1ee2e51105278265866590734c320a9789bd
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond-comm: add clear command support to consumer protocol

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I717012b855bc394bcdb524befb02a5b1ca54621b
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond-comm: Document feature branch specific commands range

Reserve a range of numbers for customer feature branches.
It is never meant to be used in the master branch.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib15ffe281c8e040231559e48b76343e67a625f4b
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd: tracefile array: Allow head position to skip ahead

The clear feature needs to move the head position ahead (jump)
over sequence numbers.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I08482bd13dd748621968c43de7647f9d19670880
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd tracefile array: add tracefile_array_reset

Required by clear feature.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I58893eb3fffbec5d39e7bf11a6d118fe23ec4496
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common dynamic-array: Introduce dynamic array clear

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I35d25b054a040c2d23b4b1c1a8137ef59ee3c7d1
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd: environment variable to disable clear command

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I04e5867220315660a373f2e49d5e6f0652a6c37e
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

lttng: Implement lttng clear session command

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: Ia51a2bf7aa7d764431eff9a45a91d5348bc9a7e5
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

lttng-ctl: Expose sessiond cmd_clear_session command

Co-developed-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Id9d169daaa1c20912a6c105b4473c3f9f2ba3b49
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common error: Add errors for clear feature

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ib7f1a99e2c5535941d6d7f9479e00762ae14b6ae
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

ust-consumer: Expose user space clear buffer operation

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I25d15b41b7186242f43339d035650ffe9f3f9936
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

kernel-ctl: Expose kernel clear buffer operation

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I582b922f577635ca66e78680fdfedb523e6dcf67
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Test: rotate_utils.sh: consider chunk archive with ust/ as empty

Now the session daemon needs to create the ust/ subdir to pass it
to the consumer daemon even if there are no active traced applications
in per-pid tracing. Therefore, we need to consider a chunk with a
ust/ empty directory as empty.

Empty local traces have this empty subdir, but remote traces do not.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic0cda7baf6eafa5b0c7b4f0b79e03bc8ea523d93
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Send ust and kernel domain directory handle to consumer

Send a directory handle to ust/ and kernel/ subdirectories of the
chunk to the consumer daemon, and alter the paths sent to consumer
so they do not include the domain subdir.

This will facilitate implementation of the clear command when no
rotation has been performed. The clear command will need to move the
ust/ and kernel/ directories to a "deleted" temporary directory while
the consumer is still actively using those directories. Making sure that
the consumer uses a handle on those subdirectories only ensures that the
consumer will not observe any transient state when those directories are
moved.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I2357ad702f810561c4d11405edc3ef204fc6c455
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: consumer: do not flush on transition from NULL chunk

When transitioning from NULL chunk, do not flush streams, because
the consumer has nowhere to store the packets generated by this
flush.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ic92c035f6b1377849825527d0c9cc05a6b92ac38
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: consumer: honor "active" flush flag

Honor "active" flush flag in both kernel and ust consumers. A flush
"active" does a flush which will not generate empty packets (no event),
whereas an "inactive" flush will generate empty packets if flushing
a current packet which has no event.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Icc9772ba3ae18e96f24354ac6eb9223f343c3458
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: sessiond cmd.h: include missing lttng-sessiond.h

lttng-sessiond.h declares struct command_ctx which is used in cmd.h
prototypes.

It typically does not generate a compilation error because all
compile units including cmd.h also include lttng-sessiond.h, but
it is cleaner to include dependencies directly in cmd.h.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: If3106291309cd543a886b2aecda7d4f9d4b290b3
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: sessiond: ust-app: per-pid buffers: Create empty ust/ directory

When no applications are running, the toplevel ust/ directory is not
created in a chunk on rotation. Make sure this top level directory
is created.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Ia272f3182df298302e02b3e096785cb51687b8c9
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: utils: utils_stream_file_path separator

Do not add a separator for empty paths.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Icec7b07d7abab4c010706c8cb4f199229fa04c6f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: consumerd: use packet sequence number for rotation position

Refer to "Fix: relayd: use packet sequence number for rotation position"
for context of this change.

This commit introduces the changes required in the consumerd.

Some notable points related to this commit:

- Internally, the rotate_position (per-stream) is now a 64-bit
  value rather than an unsigned long.
- The scheme to rotate a stream is changed to allow using the
  backward-compatible lttng_consumer_take_snapshot() rather than
  the newer lttng_consumer_get_produced_snapshot(), thus allowing
  backward compatibility of the implicit rotation on destroy with
  pre-2.10 lttng-modules.
- The rotate position used as pivot point for the rotation is
  based on the packet_seq_num of the last packet that has been
  send over the network by consumerd, incremented by the number of
  packets between the sampled produced_pos and the consumed_pos.
  In the worse case scenario where an overwrite mode ring buffer
  overwrites its contents enough to trigger a 4GB overflow on a
  32-bit producer since the last packet was sent (e.g. due to a
  slow network), the difference between produced_pos and
  consumed_pos will be lower that what would have been expected.
  However, because this pivot position is used as a lower bound,
  being smaller than the real value is fine: the data that would
  have been misplaced in the wrong trace chunk were actually
  overwritten, and will therefore never be consumed.
- When interacting with pre-2.8 lttng-modules, the packet sequence
  number is not available. The current approach is to disallow
  rotations performed on sessions which have kernel tracing active
  with a pre-2.8 lttng-modules.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I8600cb5e2e9c05f3dfba0499a5fc4a3bb85dec24
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

align.h: Implement ALIGN_FLOOR macro

Implement the ALIGN_FLOOR macro which aligns the given value to the
previous alignment boundary, or keeps the value as-is if it is already
aligned.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I36d981e8fb705fafa3ff23ba2d82ec1babe73e45
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd: per-pid live: no new metadata vs close

When using lttng-live on a per-pid UST trace, the metadata stream is
closed after an application exits. The live viewer observes that the
stream has no more data when getting the metadata returns 0 bytes.

Internally in the relay daemon, it is assumed that a metadata stream
can be put (and thus removed) as soon as all the metadata has been sent
to the viewer, but this is not quite right. The viewer actually needs to
observe a 0-byte reply after receiving all the metadata in order to
gracefully perceive the metadata stream hang up.

Therefore, add a no_new_metadata_notified flag to the metadata stream
to track whether that 0-byte message has been sent to the viewer since
the last metadata content was sent, and postpone the reclamation of the
metadata stream until it is closed _and_ that 0-byte reply was sent to
the live viewer.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0a05332284299d62b832046e4f9d22b6029c3a3e
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd: use packet sequence number for rotation position

The "network" sequence number (net_seq_num) is a 64-bit sequence number
tagging each packet sent over the network. The net_seq_num increments
monotonically (+1) for each packet sent from consumer daemon to relay
daemon, on a per-stream basis. It is tagged by the consumer daemon when
sending a trace packet to the relay daemon.

The LTTng kernel and user-space ring buffer "consumed position"
(consumed_pos) and "produced position" (produced_pos) are free-running
counters counting the number of bytes consumed and produced so far by
each stream. Because those counters are updated atomically, they are
limited to a size of 32-bit on 32-bit architectures.

The "packet" sequence number (packet_seq_num) is a sequence number
found in the packet header starting from LTTng 2.8. It is a 64-bit
sequence number assigned by the lttng-modules and lttng-ust ring
buffers. It increments monotonically (+1) for each packet produced
within a given ring buffer (stream).

Using produced_pos as rotation position and comparing it to the
net_seq_num has a few issues:

1) It breaks on 32-bit producers after generating more than 4GB of
   data per stream, due to overflow. The net_seq_num is a 64-bit
   counter, which does not overflow, but the produced_pos overflows
   after 4GB on 32-bit architectures. This can lead to never-completing
   rotations.

2) It breaks scenarios where ring buffers are configured in
   overwrite mode, and streaming to a relay daemon. Indeed, when
   the ring buffer moves the consumed_pos ahead, actually overwriting
   data within the ring buffer, it introduces an offset between the
   produced_pos and the net_seq_num. Therefore, if producers are
   generating a low- (or no-) throughput in some streams, the
   rotation may never complete, even on 64-bit architectures.

The solution proposed for this issue is to use the packet_seq_num as
rotation position rather than the net_seq_num. It takes care of
the two problematic scenarios, since the counter is always 64-bit
(even on 32-bit architectures), and because the counter is managed
by the producer, which therefore tracks progress of the ring buffer
overwrites.

This commit introduces changes required at the relayd side. A
separate commit introduces the changes required in the consumerd.

In relayd, one major restriction is the fact that the packet_seq_num
is not sent over the data socket, only through the control socket
receiving the indexes.

Therefore, in order to figure out the pivot position for the data
socket for a given stream, the associated index first needs to be
received. At that point, the corresponding net_seq_num is known,
which provides the pivot position for the data stream. Given that
the data and index sockets provide no ordering guarantees with
respect to their arrival, we handle the fact that data might have
been saved to disk in the wrong (previous) trace chunk by moving
it to the next trace chunk when the pivot position is known.

In order to allow "jumps" in the sequence numbers produced by
overwrite mode buffers, try_rotate_stream_index(), which previously
asserted that each sequence number was received in sequence, now
uses the packet_seq_num pivot position as a lower (inclusive) bound.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I755329e313f0980655a164b7bdb57e4f3d8e944a
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd stream.c: LTTNG_OPTIONAL_GET address confusion

The lack of proper care around use of macro arguments in LTTNG_OPTIONAL_GET
allowed this code to compile, but caused the following issue (manually
replacing "optional" argument with the a

Using LTTNG_OPTIONAL_GET(&stream->ongoing_rotation)->next_trace_chunk

with:

 #define LTTNG_OPTIONAL_GET(optional)                   \
         ({                                             \
               assert(optional.is_set);                 \
               optional.value;                          \
         })

translates to:

         ({
               assert(&stream->ongoing_rotation.is_set);
               &stream->ongoing_rotation.value;
         })->next_trace_chunk

The issue here is the assert(), which just checks that the address
is not NULL, when it should actually check that the value is set.

The prior commit fixing optional.h to add proper parentheses to the
macro rightfully fails to compile this code. Fix the erroneous user.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I0dd45fb60573cae6ae3e831e24266aff4406f57f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: optional.h macro missing parentheses and guards

The are a few coding style issues with optional.h which leads to
unexpected effects when the macros are used in the caller code.

All macro parameters need to be surrounded by () (except when used near
commas, which is the C operator with least precedence).

All macros that emit code need to be surrounded by do { } while (0) so
not to emit extra ; or omit ;, which can cause subtle issues when used
with if/else statements.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: Iba6fde7c267f4d8c9ec1a89147045f0bcda3a67a
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: use of strnlen breaks build on Solaris 10

The new uuid helper library makes use of strnlen directly, which
doesn't exist on Solaris 10. Using the compat version solves this.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ie491da37f968fac417e265b5641fdf0dd3298813

dynamic-array: fix documentation of lttng_dynamic_pointer_array_get_pointer

The documentation of this function says that mutating the array
invalidates the return pointer.  This is not true, since the returned
pointer is the element itself, not a pointer to the array.

Change-Id: I8b8978cddb2d1d6ce0b42ed313e9843ca418c96c
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: make dist fails on sdt-probe test with autotools v1.16+

The 'dist' target fails when building with autotools 1.16.1 as the
behaviour of BUILT_SOURCES has changed in 1.16 [1].

BUILT_SOURCES are now built as part of the 'dist' target which causes
it to fail on machines that don't have dtrace installed.

The following error is produced: DTRACE foobar_provider.h /bin/sh: -s:
  command not found

The BUILT_SOURCES is skipped for build configurations where the build
of the test helper 'userspace-probe-sdt-binary' is disabled.

The resulting artifact, foobar_provider.h, is not part of the
distributed tarball (marked as nodist), so this doesn't have any
adverse effect.

[1] https://www.mail-archive.com/automake@gnu.org/msg20156.html

Signed-off-by: Michael Jeanson <michael.jeanson@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ibba4689775a8b002e8a959079b1f3c8db9917c5f

Fix: tests: metadata presence on relayd is not deterministic

There is no synchronization point guaranteeing the presence of metadata on
lttng-relayd side when the live metadata request is done. It must be
present at some point in the future but might not be at the moment we
perform the request.

Add a retry phase to this step. It must succeed in the future.

Not sure how this test was never marked as flaky.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I033005c6a228013e699c74d8e8faafcb3272dd98
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: move testpoint after state update

This prevent failure and hang for the long_regression test suite.

Otherwise the sessiond error out before the test completion due to an
invalid thread state.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: Ie4bf3bea6f84f49f5eceb413ae75a7e6fff08a8f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Make lttng_directory_handle reference countable

Currently, the lttng_directory_handle API assumes that the caller has
exclusive ownership of the lttng_directory_handle. Directory handles
are passed by reference and populated by an "init" method and
finalized using the "fini" method.

In order to allow multiple references to a path or directory file
descriptor in follow-up patches, the API is moved to a model where
directory handles are dynamically allocated and released using the
"put" method.

No change in behaviour is intended by this change beyond adapting the
API.

The objective of the change is to make it easier to implement copy
operations of trace chunks that are configured to use an fd-tracker
and reduce the number of open file descriptors when
lttng_directory_handles are copied.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ibc8e97ea9e949adafef44533c30b61e3a9fa1f7d

Clean-up: apply clang-format to the newly added fd-tracker

The fd-tracker code was just merged but clang-format found some
changes to apply. Since there is no need to backport to this code
yet, clean it up as much as possible now.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ia0bec41e0531c9f5d611d742e96a984de3f06784

Fix build: fd-tracker is not part of librelayd

The fd-tracker library is not part of the internal librelayd; it is
its own stand-alone library.

Add an autoconf conditional to build libfd-tracker by default
and require it when building the relay daemon.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I40934eeaa62e61f5da4508c1f2c91daaa9e57829

Add git-review config

Add .gitreview for contributors wishing to use gerrit for patch
reviews.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I74c017eeac05c9092be145265e6ce060dddcd791

doc: fix typo in lttng-enable-event man page

Change-Id: I81ce8f5d4eb3857ace5b1bc3a3ed3c62751dc503
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make functions static in test_notification.c

Fixes:

      CC       test_notification.o
    /home/smarchi/src/lttng-tools/tests/unit/test_notification.c:50:6: error: no previous declaration for ‘test_condition_buffer_usage’ [-Werror=missing-declarations]
     void test_condition_buffer_usage(struct lttng_condition *buffer_usage_condition)
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_notification.c:265:6: error: no previous declaration for ‘test_condition_buffer_usage_low’ [-Werror=missing-declarations]
     void test_condition_buffer_usage_low(void)
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_notification.c:280:6: error: no previous declaration for ‘test_condition_buffer_usage_high’ [-Werror=missing-declarations]
     void test_condition_buffer_usage_high(void)
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_notification.c:295:6: error: no previous declaration for ‘test_action’ [-Werror=missing-declarations]
     void test_action(void)
          ^~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_notification.c:305:6: error: no previous declaration for ‘test_trigger’ [-Werror=missing-declarations]
     void test_trigger(void)
          ^~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I4df29ec42436798005e740d5b6fb34973ea22350
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make functions static in test_utils_compat_poll.c

Fixes:

      CC       test_utils_compat_poll.o
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_compat_poll.c:74:6: error: no previous declaration for ‘test_alloc’ [-Werror=missing-declarations]
     void test_alloc(void)
          ^~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_compat_poll.c:95:6: error: no previous declaration for ‘test_add_del’ [-Werror=missing-declarations]
     void test_add_del(void)
          ^~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_compat_poll.c:133:6: error: no previous declaration for ‘test_mod_wait’ [-Werror=missing-declarations]
     void test_mod_wait(void)
          ^~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_compat_poll.c:189:6: error: no previous declaration for ‘test_func_def’ [-Werror=missing-declarations]
     void test_func_def(void)
          ^~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I1feeed8ee3f76783e22ffedd5292a06deee3e233
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make functions static in test_utils_expand_path.c

Fixes:

      CC       test_utils_expand_path.o
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_expand_path.c:126:5: error: no previous declaration for ‘prepare_valid_results’ [-Werror=missing-declarations]
     int prepare_valid_results(void)
         ^~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_expand_path.c:182:5: error: no previous declaration for ‘free_valid_results’ [-Werror=missing-declarations]
     int free_valid_results(void)
         ^~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_expand_path.c:195:5: error: no previous declaration for ‘prepare_symlink_tree’ [-Werror=missing-declarations]
     int prepare_symlink_tree(void)
         ^~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_utils_expand_path.c:235:5: error: no previous declaration for ‘free_symlink_tree’ [-Werror=missing-declarations]
     int free_symlink_tree(void)
         ^~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I220a2f8dadb355adb4fb974a2f3a0e161b0618e6
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make functions static in test_session.c

Fixes:

      CC       test_session.o
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:219:6: error: no previous declaration for ‘test_session_list’ [-Werror=missing-declarations]
     void test_session_list(void)
          ^~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:225:6: error: no previous declaration for ‘test_create_one_session’ [-Werror=missing-declarations]
     void test_create_one_session(void)
          ^~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:232:6: error: no previous declaration for ‘test_validate_session’ [-Werror=missing-declarations]
     void test_validate_session(void)
          ^~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:258:6: error: no previous declaration for ‘test_destroy_session’ [-Werror=missing-declarations]
     void test_destroy_session(void)
          ^~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:278:6: error: no previous declaration for ‘test_duplicate_session’ [-Werror=missing-declarations]
     void test_duplicate_session(void)
          ^~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:284:6: error: no previous declaration for ‘test_session_name_generation’ [-Werror=missing-declarations]
     void test_session_name_generation(void)
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_session.c:309:6: error: no previous declaration for ‘test_large_session_number’ [-Werror=missing-declarations]
     void test_large_session_number(void)
          ^~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ib1f6a004e6feb4693c4331a8b0ce67ee1697703c
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make functions static in test_uri.c

Fixes:

      CC       test_uri.o
    /home/smarchi/src/lttng-tools/tests/unit/test_uri.c:33:6: error: no previous declaration for ‘test_uri_parsing’ [-Werror=missing-declarations]
     void test_uri_parsing(void)
          ^~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/unit/test_uri.c:201:6: error: no previous declaration for ‘test_uri_cmp’ [-Werror=missing-declarations]
     void test_uri_cmp()
          ^~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ia0d7b08a10ec9f8d3f6f2d5b4fa9c4f417827024
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: include foo.h in foo.c

Fixes:

      CC       foo.lo
    /home/smarchi/src/lttng-tools/tests/utils/testapp/userspace-probe-elf-binary/foo.c:19:5: error: no previous declaration for ‘dynamic_symbol’ [-Werror=missing-declarations]
     int dynamic_symbol(int a)
         ^~~~~~~~~~~~~~

Change-Id: I58888da2908bcf4c38d59ba9bacf3e96adc575b6
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

compat: remove always true assertion in compat-poll.c

Fix:

      CC       compat-poll.lo
    In file included from /home/smarchi/src/lttng-tools/src/common/compat/poll.h:21:0,
                     from /home/smarchi/src/lttng-tools/src/common/compat/compat-poll.c:31:
    /home/smarchi/src/lttng-tools/src/common/compat/compat-poll.c: In function ‘compat_poll_wait’:
    /home/smarchi/src/lttng-tools/src/common/compat/compat-poll.c:317:31: error: comparison of unsigned expression >= 0 is always true [-Werror=type-limits]
      assert(events->current.nb_fd >= 0);
                                   ^

Change-Id: Ie2b43e64d293d4eadb82db9755dfb64751a1d935
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: sessiond: RCU read lock imbalance on get trace chunk id error

The error path when cmd_setup_relayd() fails to get the ID of a trace
chunk causes the RCU read lock to be released even though it was never
acquired.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I86aeb99e6cd6ba11634283ab7456a3760a0a6b0d

tests: add declaration for test_function in userspace-probe-elf-binary.c

Fixes:

      CC       userspace-probe-elf-binary.o
    /home/smarchi/src/lttng-tools/tests/utils/testapp/userspace-probe-elf-binary/userspace-probe-elf-binary.c:21:34: error: no previous declaration for ‘test_function’ [-Werror=missing-declarations]
     void __attribute__ ((noinline))  test_function()
                                      ^~~~~~~~~~~~~

I did not make test_function static, because from what I understand, it
is important that test_function remains an exported symbol, for example
for test regression/kernel/test_userspace_probe.

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I52019f69de023b24b46cc701e2e0df919e654a76
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: add declarations for functions in gen-syscall-events-callstack.c

Fixes:

      CC       gen-syscall-events-callstack.o
    /home/smarchi/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:46:1: error: no previous declaration for ‘my_gettid’ [-Werror=missing-declarations]
     my_gettid(void)
     ^~~~~~~~~
    /home/smarchi/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:72:1: error: no previous declaration for ‘fct_c’ [-Werror=missing-declarations]
     fct_c(void)
     ^~~~~
    /home/smarchi/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:78:1: error: no previous declaration for ‘fct_b’ [-Werror=missing-declarations]
     fct_b(void)
     ^~~~~
    /home/smarchi/src/lttng-tools/tests/utils/testapp/gen-syscall-events-callstack/gen-syscall-events-callstack.c:85:1: error: no previous declaration for ‘fct_a’ [-Werror=missing-declarations]
     fct_a(void)
     ^~~~~

From what I understand, it is important that these symbols stay exported
for test regression/kernel/test_callstack.

Change-Id: I656a4e77bb2653510ba971e94ccc0d8bb65be698
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: make entry_handler static in ini_config test

Fixes:

      CC       ini_config.o
    /home/smarchi/src/lttng-tools/tests/unit/ini_config/ini_config.c:37:5: error: no previous declaration for ‘entry_handler’ [-Werror=missing-declarations]
     int entry_handler(const struct config_entry *entry,
         ^~~~~~~~~~~~~

Change-Id: I937fda691d5ab81bf7567ab50fd90903911dfc57
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Format lists in src/common/Makefile.am

I'm currently dealing with src/common/Makefile.am, and would find it
more pleasant to modify if the lists were formatted consistently and
sorted (except DIST_SUBDIRS, for which the order is important).

I have taken the liberty to put the corresponding .c and .h on the same
line, since they will always be next to each other.  It reduces a bit
the number of lines.  If you don't like that, I would also be fine with
a completely flat list.

Change-Id: I8a65fe5e0fea37230f1376c51c7d4a547f651c7e
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: make functions static in ust-registry.c

Fixes:

      CC       ust-registry.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/ust-registry.c:553:2: error: no previous declaration for ‘ust_registry_lookup_enum’ [-Werror=missing-declarations]
      ust_registry_lookup_enum(struct ust_registry_session *session,
      ^~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/ust-registry.c:684:6: error: no previous declaration for ‘ust_registry_destroy_enum’ [-Werror=missing-declarations]
     void ust_registry_destroy_enum(struct ust_registry_session *reg_session,
          ^~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ibaabd16a75f0b7b13a641a571d26ca64aec5317b
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: make thread_consumer_management function static

Fixes:

      CC       manage-consumer.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/manage-consumer.c:64:7: error: no previous declaration for ‘thread_consumer_management’ [-Werror=missing-declarations]
     void *thread_consumer_management(void *data)
           ^~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Id28f40244e12a618749cc618466fc31d6d773378
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: make thread_rotation function static

Fixes:

      CC       rotation-thread.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/rotation-thread.c:799:7: error: no previous declaration for ‘thread_rotation’ [-Werror=missing-declarations]
     void *thread_rotation(void *data)
           ^~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ia95212a53c658bce5dc6df155eb43ee29b7980c6
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: build: ust -> kernel mix-up in noinst_SCRIPTS

This is simply a copy paste error as test_notification_ust appears
twice.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Change-Id: I4e170a092338f5a95479a58d48247088d28d3e31
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd: missing metadata stream causes all traces to be skipped

Commit 123ed7c22 intends for a trace that doesn't have a metadata
stream to be skipped when creating viewer streams. However, the loop
over ctf_traces should be "continued" rather then "broken" from when
this situation arises. Otherwise, all ctf_traces of the session are
skipped, which is not the intention here.

Moreover, a reference to the current ctf_trace is leaked when the
break (now continue) occurs.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: Ic630521c6f050c77a78f2c1e20c5741a6b3a66a1

lttng-ctl: add local declarations for obsolete functions in lttng-ctl.c

The functions concerned by this change are obsolete, but kept to avoid
breaking the ABI.  This patch adds local declaration for these functions
to silence the following errors, when building with
-Wmissing-declarations.

      CC       lttng-ctl.lo
    /home/smarchi/src/lttng-tools/src/lib/lttng-ctl/lttng-ctl.c:2815:5: error: no previous declaration for ‘lttng_enable_consumer’ [-Werror=missing-declarations]
     int lttng_enable_consumer(struct lttng_handle *handle)
         ^~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/src/lib/lttng-ctl/lttng-ctl.c:2823:5: error: no previous declaration for ‘lttng_disable_consumer’ [-Werror=missing-declarations]
     int lttng_disable_consumer(struct lttng_handle *handle)
         ^~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/src/lib/lttng-ctl/lttng-ctl.c:2831:5: error: no previous declaration for ‘_lttng_create_session_ext’ [-Werror=missing-declarations]
     int _lttng_create_session_ext(const char *name, const char *url,
         ^~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I49750d7646d5823461933c13a9ec4ccef905921c
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: remove unused log_job_destruction function

Fixes:

      CC       rotation-thread.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/rotation-thread.c:114:6: error: no previous declaration for ‘log_job_destruction’ [-Werror=missing-declarations]
     void log_job_destruction(const struct rotation_thread_job *job)
          ^~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I3fce2aceb047a2a251d61e84bff5862be49fe593
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: make disable_context static

Fixes:

      CC       agent.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/agent.c:833:5: error: no previous declaration for ‘disable_context’ [-Werror=missing-declarations]
     int disable_context(struct agent_app_ctx *ctx, enum lttng_domain_type domain)
         ^~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I3f8eb7e658e558f7082781c95b4200607e5dad6f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

sessiond: make ltt_sessions_ht_alloc static

Fixes:

      CC       session.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-sessiond/session.c:305:5: error: no previous declaration for ‘ltt_sessions_ht_alloc’ [-Werror=missing-declarations]
     int ltt_sessions_ht_alloc(void)
         ^~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Iaf4ca32c1f6ca01fa7ad4a1bfc7edd81a90e6adc
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd: make functions static in ctf-trace.c

Fixes:

      CC       ctf-trace.o
    /home/smarchi/src/lttng-tools/src/bin/lttng-relayd/ctf-trace.c:47:6: error: no previous declaration for ‘ctf_trace_destroy’ [-Werror=missing-declarations]
     void ctf_trace_destroy(struct ctf_trace *trace)
          ^~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/src/bin/lttng-relayd/ctf-trace.c:62:6: error: no previous declaration for ‘ctf_trace_release’ [-Werror=missing-declarations]
     void ctf_trace_release(struct urcu_ref *ref)
          ^~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I4c7ff97b3350d2e50530fb0666c5a7d02599f99f
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Make validate_url_option_combination static in create.c

Fixes:

      CC       commands/lttng-create.o
    /home/smarchi/src/lttng-tools/src/bin/lttng/commands/create.c:640:5: error: no previous declaration for ‘validate_url_option_combination’ [-Werror=missing-declarations]
     int validate_url_option_combination(void)
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I091b875fb93d4214c47a1c229e6360ec02a0a2f8
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Make _utils_expand_path static

It's only used in its own file, so make it static.

Fixes:

      CC       utils.lo
    /home/smarchi/src/lttng-tools/src/common/utils.c:328:7: error: no previous declaration for ‘_utils_expand_path’ [-Werror=missing-declarations]
     char *_utils_expand_path(const char *path, bool keep_symlink)
           ^~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Ibab3bf9994f29b1a841e9d3ddc9bfce1f8e73032
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Remove unused function uri_create

Fixes:

      CC       uri.lo
    /home/smarchi/src/lttng-tools/src/common/uri.c:273:19: error: no previous declaration for ‘uri_create’ [-Werror=missing-declarations]
     struct lttng_uri *uri_create(void)
                       ^~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I18a58391842c3fba1fa3dd60cf5fe3215280f95a
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

uri: put `inline` at beginning of strpbrk_or_eos declaration

Fixes:

      CC       uri.lo
    /home/smarchi/src/lttng-tools/src/common/uri.c:64:1: error: ‘inline’ is not at beginning of declaration [-Werror=old-style-declaration]
     static const inline char *strpbrk_or_eos(const char *s, const char *accept)
     ^~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I2f753143e65ac4301abc01fba3e9ef122b2d38b7
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

tests: put `static` keyword at beginning of variable declaration

Fix:

  CC       select_poll_epoll-select_poll_epoll.o
/home/smarchi/src/lttng-tools/tests/regression/kernel/select_poll_epoll.c:34:1: error: ‘static’ is not at beginning of declaration [-Werror=old-style-declaration]
 volatile static int stop_thread;
 ^~~~~~~~

Change-Id: I2cf1a7d50a01ca0e9226ea527f2e8af70a292f94
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

common: make some functions static in mi-lttng.c

These two functions are only used in the file, so make them static.

Fixes:

      CC       mi-lttng.lo
    /home/smarchi/src/lttng-tools/src/common/mi-lttng.c:367:13: error: no previous declaration for ‘mi_lttng_eventtype_string’ [-Werror=missing-declarations]
     const char *mi_lttng_eventtype_string(enum lttng_event_type value)
                 ^~~~~~~~~~~~~~~~~~~~~~~~~
    /home/smarchi/src/lttng-tools/src/common/mi-lttng.c:1317:5: error: no previous declaration for ‘mi_lttng_event_userspace_probe’ [-Werror=missing-declarations]
     int mi_lttng_event_userspace_probe(struct mi_writer *writer,
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

There are a bunch of other stuff in mi-lttng.c that could be made
static, but those were the only two problematic with
-Wmissing-declarations, because there have no declaration in the .h.

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I9f3a6b0f71e86fac7af5d40e553a6944eb768fbe
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

consumerd: make lttng_consumer_close_all_metadata static

It is only used in its file, so make it static.  Fixes:

      CC       consumer.lo
    /home/smarchi/src/lttng-tools/src/common/consumer/consumer.c:2177:6: error: no previous declaration for ‘lttng_consumer_close_all_metadata’ [-Werror=missing-declarations]
     void lttng_consumer_close_all_metadata(void)
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I211a31a7fb5edfb76e90f1209e69bbed5dd5ec92
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

README.md: libuuid is no longer a dependency

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I68ce6b7d210a5f645892267968cd01c8347b2370

Replace libuuid with internal implementation

We use a very small subset of libuuid features to transform UUIDs
between their string and binary representation. Plus we have a lot of
compat code for different platforms with some unspecified default
behavior regarding the use of upper/lower case.

Drop the dependency on libuuid and replace it with a minimal internal
implementation that respects RFC4122.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Change-Id: I744e3cf65d6a22d0acf7a9943c10943ba64e8468
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

consumerd: remove unused function consumer_del_data_stream

Fix:

      CC       consumer.lo
    /home/smarchi/src/lttng-tools/src/common/consumer/consumer.c:712:6: error: no previous declaration for ‘consumer_del_data_stream’ [-Werror=missing-declarations]
     void consumer_del_data_stream(struct lttng_consumer_stream *stream)
          ^~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: I92a47e069055713eaa4fdbc7f034a8f8e439f283
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

m4: sync ax_pthread.m4 with autoconf archive

Sync with [1].

In particular, this lets us configure with -Wunused-but-set-parameter.

[1] https://raw.githubusercontent.com/autoconf-archive/autoconf-archive/62e8491dbc174113a04fe910cad1e92e8a9e2164/m4/ax_pthread.m4

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Change-Id: Id9a6eb7cd0b8c7597ae6abb5587078afdaa420f6
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

configure.ac: Remove duplicated CMD_DESCR_ROTATE definition

CMD_DESCR_ROTATE is defined twice by configure.  This breaks configuring
with "-Werror -Wall", as some test programs don't compile due to:

  configure:16990: gcc -o conftest -Wall -Werror   conftest.c  >&5
  conftest.c:163: error: "CONFIG_CMD_DESCR_ROTATE" redefined [-Werror]
   #define CONFIG_CMD_DESCR_ROTATE "Archive a tracing session’s current trace chunk"

  conftest.c:154: note: this is the location of the previous definition
   #define CONFIG_CMD_DESCR_ROTATE "Archive a tracing session's current trace chunk"

  cc1: all warnings being treated as errors

Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: tests: missing argument in test output print statement

The format string of this print statement uses a string and none
is provided. This results in a crash when running on ARM64
test boards.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Silence bogus warning when building with old GCC versions

gcc version 7.4.0 (and possibly others) warn that `new_handle`
may be used uninitialized. It is not clear what code path would
trigger this uninitialized use.

Moreover, the warning is not present when building with recent
versions of gcc and clang, nor is it flagged by Coverity. This points
to the warning being bogus.

Still, setting `new_handle` to NULL silences the warning on this
gcc version.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Clean-up: open_pipe_cloexec() has useless boilerplate

The open_pipe_cloexec() wrapper can be simplified to simply call
utils_create_pipe_cloexec(). This eliminates a warning of Coverity.

1407700 Identical code for different branches
The condition is redundant
In open_pipe_cloexec: The same code is executed regardless of the condition (CWE-398)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Clean-up: tests: unchecked closedir value in test_fd_tracker

closedir's return value is not checked in a utility function
of the test_fd_tracker unit test.

1407702 Unchecked return value
If the function returns an error value, the error value may be mistaken for a normal value.
In fd_count: Value returned from a function is not checked for errors before being used (CWE-252)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: fd-tracker: dereference of lttng_inode after NULL check

handle->inode is checked for NULL but used unconditionaly
on line 873 (lttng_inode_put).

1407756 Dereference after null check
Either the check against null is unnecessary, or there may be a null pointer dereference.
In fs_handle_close: Pointer is checked against null but then dereferenced anyway (CWE-476)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: fd-tracker: error path lead to null dereference of handle

A number of fd_tracker_open_fs_handle() error paths can lead to a NULL
pointer dereference. The error paths are separated to cover the
various initialization stages of an fs_handle.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: fd-tracker: crash on close of partially initialized handle

A number of internal functions are used in the error path of the
creation of an fs_handle. Since the fs_handle is partially
initialized, those functions need to be adapted to handle cases where
internal members are NULL.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Tests: add fd-tracker tests for the unlink operation

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: use lttng_inode to store fs_handle's path

Storing paths as part of the lttng_inode object, which may be shared
by multiple fs_handles reduces the number of copies of the path.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: add the lttng-inode interface

The lttng-inode interface is internal to the fd-tracker. It allows
unlink operations on an fs_handle to determine if another fs_handle
refers to the same file.

When this is deemed to be the case, the unlink can be delayed by
renaming the file to a temporary name and, finally, unlinking it
when all references have been released.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: add the unlink operation to fs handles

The unlink method allows user to unlink the file refered-to by
an fs_handle. As indicated in the comments, the unlink operation
leverages the lttng_inode to ensure the actual unlink system call
is only performed when the last reference to an lttng_inode is
released by an fs_handle.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Test: add a unit test for the fd tracker

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: add pipe management wrappers to fd-tracker

Add wrappers to allow the creation of a pipe the two ends of
which are tracked by an fd-tracker.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: add epoll/poll management wrappers to fd-tracker

Add wrappers which create an lttng_poll_event object, tracking
any file descriptor created in the process of initializing
the object.

When the build is configured to use the epoll interface, the
underlying epoll fd is tracked by the fd-tracker.

If the build is configured to use the poll interace, the fd tracker is
not involved in the process and the utility will simply defer the call
to lttng_poll_create() directly.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

fd-tracker: add an fd-tracker util to common

This commit adds an fd-tracker utility to the common libs.
This interface allows a process to keep track of its open
file descriptors and enforce a limit to the number of file
descriptors that may be simultaneously opened.

The intent is to use this interface as part of the relay daemon
to mitigate file descriptors exhaustion problems that are
encountered when the relay has to handle a large number of streams.

The fd-tracker defines two classes of file descriptors: suspendable
and unsuspendable file descriptors.

Suspendable file descriptors are handles to filesystem objects
(e.g. regular files) that may be closed and re-opened later without
affecting the application.

A suspendable file descriptor can be opened by creating a filesystem
handle (fs_handle) using the fd-tracker. The raw file descritptor
must then be obtained and released using that handle. Closing the
handle will effectively ensure that the file descritptor is closed.

Unsuspendable file descriptors are file descriptors that cannot
be closed without affecting the application's state. For instance,
it is not possible to close and re-open a pipe, a TCP socket, or
an epoll fd without involving some app-specific logic. Thus, the
fd-tracker considers those file descriptors as unsuspendable.

Opening an unsuspendable file descritptor will return a raw file
decriptor to the application. It is its responsability to notify the
fd-tracker of the file descriptor's closing to ensure the number
of active file descriptors can be tracked accurately.

If a request to open a new file descriptors is made to the fd-tracker
and the process has already reached its maximal count of
simultaneously opened file descriptors, an attempt will be made to
suspend a suspendable file descriptor to release a slot.

Suspending a file descriptor involves:
  - verifying that the file is still available on the FS (restorable),
  - sampling its current position,
  - closing the file descriptor.

Note that suspending a file descriptor eliminates the POSIX guarantee
that a file may be unlinked at any time without affecting the
application (provided that it holds an open FD to that
file). Applications using the fd-tracker that need to maintain this
guarantee should open those files as unsuspendable file descriptors.

To protect against unlinking and file replacement scenarios, the
fd-tracker samples the files' inode number when a fs_handle is
created. This inode number will then be checked anytime the handle
is suspended or restored to ensure that the application is made
aware of the file's unavailability. This is preferable to
inadvertently opening another file of the same name if the original
file was unlinked and/or replaced between a fs_handle's suspension
and restoration.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

relayd: close stdin on launch

The relay daemon has no use for the standard input; it can be safely
closed early on launch.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd: fully initialize viewer stream before publishing it

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Clean-up relayd: session_release can be marked as static

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

Fix: relayd: don't send streams if there is no metadata

Issue
=====
When tracing short-live UST apps in per-pid mode, it happens that traces
are closed before we can send all the streams to the viewer. This can
place the viewer in an uncomfortable position where it is aware of data
streams of a trace but can't get the metadata stream to decode the
events.

Solution
========
Only send the data streams if we have the metadata stream or if the
metadata stream was already sent. This ensures that the viewer will
either have all the {data,metadata} streams or none of them.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>