Add stream instance id to the packet header

This new field allows the viewer to distinguish between trace files
belonging to the same packet stream (in LTTng: the same CPU in the same
channel).

This is a locked-step with the corresponding commit in lttng-tools.

Signed-off-by: Julien Desfossez <jdesfossez@efficios.com>
Acked-by: Mathieu.Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: print empty line after AC_OUTPUT

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: macros with no arguments do not need ()

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: standardize indentation to tabs

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: move AC_PROG_SED() close to other AC_PROG_*()

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: test -a -> shell's && (more portable)

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: use test "x$var" = "xyes"

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: AM_CONDITIONAL() accepts two arguments

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: use dnl at appropriate places

Use dnl where such a comment makes no sense in the outputted
configure script.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: if -> AS_IF()

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: case -> AS_CASE()

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: add missing quotes in macro calls

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: use macros for version name and description

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

configure.ac: do not use shell eval for known values

The version parts are known at Autoconf time, thus it makes no
sense to do string manipulation using the user's shell.

Just dnl the V_EXTRA definition when there's no extra version.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add CONTRIBUTING.md

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Output "(null)" when ctf_string()'s arg is NULL

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: disable use of __builtin_return_address(0) on 32-bit PowerPC

It causes stack corruption in the tracepoint event probes.

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

Fix: java agent 32-bit pointer to jlong warning

Fix the following compiler warning on 32-bit:

15:07:12 lttng_ust_context.c: In function 'Java_org_lttng_ust_agent_context_LttngContextApi_registerProvider':
15:07:12 lttng_ust_context.c:377:17: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
15:07:12   provider_ref = (jlong) provider;

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

Fix: Use Java 6 syntax in JUL examples

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing example file to dist tarball

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

Fix: add missing header to dist tarball

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

Fix: add missing LttngContextApi.java to dist tarball

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

Pass the Java app context information using two separate arrays

Instead of using one array with length limits for strings, we can
pass two separate arrays: the first will continue to contain fixed-
size entries, but instead of 256 bytes for strings, we will use
4-byte offsets to a second array, which will contain only those
variable-length strings.

The advantage is that we pass less bytes overall, and we don't
limit the context names or values to 256 bytes anymore.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Correctly report filter notifications on Java agent teardown

If a Java agent gets disposed, it should not just clear() all its
tracked event rules: it should first send corresponding filter change
notifications indicating that these rules are not tracked anymore.

This fixes a problem where if event rules were still enabled on agent
tear down, the filter notifier's own tracked events would become out
of sync.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add some logging to the AbstractLttngAgent

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Clear tracked application contexts upon closing a Java agent

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce a verbose mode for the Java agent

If the LTTNG_UST_DEBUG environment variable is defined, log messages
from the Java agent will be sent to stderr. This is in line with the
rest of UST.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Implement Java agent application context retrieval

Java application can now register an IContextInfoRetriever to provide
context information. This information can be used for filtering:

  lttng enable-event -j myevent --filter '$app.retriever:context=="something"'

or for saving in the trace directly by enabling the context:

  lttng add-context -j -t '$app.retriever:context'

See the "ApplicationContextExample.java" program for an example of
utilization.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Turn ISessiondCommand into an abstract class

This will allow us to define common methods to read strings passed on
the socket, which many commands (including upcoming ones) need to do.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Split the JNI APIs in separate classes

Isolate the "native" methods in their own class, to better reflect
what is present in the equivalent C files.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add app context support to ust-ctl protocol

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

Handle application context cmd

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

Implement dynamic types, and application context provider support

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

Fix: handle negative range for LTTNG_UST_REGISTER_TIMEOUT

We should not consider values below -1 as valid timeout values, this is
is unexpected and could lead to EINVAL errors returned by sem_timedwait.

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

Fix: Ensure the Java JUL messages are correctly formatted

It is possible for log records to contain messages that need some
formatting, for example if the string contains localized elements
or if the log(Level, String, Object[]) method is used.

In these cases, we need to make sure to format the string and not
pass the "raw" string to the tracepoint.

This only applies to the JUL API. log4j 1.2.x did not handle such
formatting, although log4j 2.x does.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: double-free on error sending fields

Found by Coverity:
*** CID 1348462:    (USE_AFTER_FREE)

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

Add CTF enum type support to tracepoint event

Derived from initial implementation by:
Geneviève Bastien <gbastien+lttng@versatic.net>

Bump UST communication protocol version to 6.1 (minor version increase)
since we're adding enumeration notification command.

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

Fix: missing _GNU_SOURCE define

O_CLOEXEC requires _GNU_SOURCE.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

python-lttngust/setup.py.in: update setup() fields

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Refactor Python agent build and install

Since the Python agent's tracepoint provider,
liblttng-ust-python-agent, does not depend on Python, it can
always be built and installed alongside LTTng-UST.

The Python package of this agent is completely independent
from the rest of the tree, thus it is isolated in its own
directory. This also eases the creation of distribution
packages because the packager can selectively build and
install the Python package without also building/installing the
tracepoint provider.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: remove debugging print() call from Python agent

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: header size larger than 256 bytes

When adding large context (e.g. callstack), headers larger than 256
bytes cause discrepancy between calculated size and size written into
the trace buffers. This generates a corrupted trace and triggers a
warning in ring buffer backend, which triggers a safety net disabling
tracing for the current channel.

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

Python agent: Support Agent protocol v2.0

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

Fix: Java agent protocol network endianness consistency

Considering the Agent Protocol is bumped to v2.0 as of 2.8.x,
this patch revisits the unfortunate decision of communicating
in host-endianness from the session daemon to the agents, and
in big endian from the agents to the session daemon.

This change does not affect the Python agent which was erroneously
(although quite reasonably) assuming communications were occurring
in network endianness.

This issue does not affect versions 2.7 and below because the loglevel
was not used.

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

Fix: examples jul: add missing files to make dist

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

Fix: Filer -> Filter typo in example

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

Fix: Return the correct list of available Java events

The "lttng list -j/-l" command should list the events that are currently
offered by Java application and available to be enabled.

Due to some confusion in the implementation of the corresponding agent
command response, it was actually returning the list of events that were
enabled in the tracing session.

Rectify this by sending the list of loggers of the corresponding domain
that have one or more LTTng log handlers attached. The interface method
was also renamed from listEnabledEvents() to listAvailableEvents() to
make it more representative.

Fixes: #933
Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add a toString() to Java agent's EventRule

Helps with debugging and eventually for pretty-printing.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add API stubs for the Java context info retrievers

A context info retriever will allow an application to define their own
context information, and have it available in the resulting UST traces.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Receive the event filter string in the Java agent

Update to agent protocol 2.0, which now sends the filter string as part
of the "enable event" command.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Document the Java filter notification model

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add filter change notification mechanism to the Java agent

Java applications can now register to receive notifications of event
filtering rules being changed in the tracing session. This can be
used to implement application-specific filtering on the Java side,
to reduce the amount of events sent through JNI.

To do so, they need to implement a IFilterChangeListener and register
it to the FilterChangeNotifier. The listener's callbacks will
be invoked by the LTTng agent when the tracing session(s) change.

A new example file is provided to demo this usage.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Manage complete "event rules" in the Java agent

Instead of just tracking which event names are enabled in the tracing
session, we can track the complete name/filter/loglevel tuple. This
allows the same event name to be specified multiple times but with
different parameters.

Right now the sessiond does not send the filter string, a new protocol
version will be required to do so. But we can prepare for it in the
meantime.

The agent will continue to use the event names to decide if events
should be sent through JNI or not. However, full rules will be useable
for other purposes, like the upcoming filter notifications.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Introduce a new client listener interface for the Java agent

Decouple the TCP client from the implementation of the LTTng Java agent.
Instead of using AbstractLttngAgent directly, the TCP client (and the
command subclasses) can deal with the new ILttngTcpClientListener
interface. The agent will implement this interface.

This will also allow easier testing of the TCP client and its protocol,
since test classess can now implement their own listener and verify the
contents of each command.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Turn ILttngAgentResponse into an abstract class

This allows defining a default behavior for the getBytes() method.
That behavior consists of only returning the integer return code,
which is what most (but not all) subclasses use.

Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Remove stale tests/java-jul test

This test has been superseded by lttng-tools tests and
https://github.com/lttng/lttng-ust-java-tests .

This test was not in configure.ac nor had any automake Makefile.am
anyway.

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

Fix: live timer calculation error

There is an calculation error for live timer. Variable
chan->switch_timer_interval is based on microsecond, and it is not right
to assign chan->switch_timer_interval mod 1000000 to var tv_nsec which
is based on nanosecond.

Signed-off-by: Mikael Beckius <mikael.beckius@windriver.com>
Signed-off-by: Jianchuan Wang <jianchuan.wang@windriver.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix python agent build/install/uninstall with DESTDIR specified

Remove the install_files.txt record since it's simpler to delete the
complete folder on uninstall.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Don't (re)define STAP_PROBEV

Define a new LTTNG_STAP_PROBEV macro to avoid clobbering STAP_PROBEV or
emitting unwanted sdt probes when lttng-ust has been built without sdt
support.

Signed-off-by: Stelios Bounanos <sb@enotty.net>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: don't dereference NULL pointers

Detected by scan-build.

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

Cleanup: Remove unused values

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

Fix: Value stored to 'has_waited' is never read

Reported by scan-build.

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

Fix: Argument with 'nonnull' attribute passed null

Reported by scan-build
API Argument with 'nonnull' attribute passed null libringbuffer
/ring_buffer_backend.c 380
API Argument with 'nonnull' attribute passed null libringbuffer
/ring_buffer_backend.c  420

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

Cleanup: Unnecessary bit shift

Reported by cppcheck [1].

[1]
https://ci.lttng.org/view/Code%20quality/job/lttng-ust_master_cppcheck/5/cppcheckResult/source.10/

Proposed-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Clean-up: remove extraneous "found" parameters in ust-elf

In lttng-ust-elf.c, static functions used to extract build ID or debug
link information had an extraneous `found` parameter, carrying no more
information than could be obtained by checking the other out
parameters against NULL. The resulting simplified logic should also
prevent static analysis tools from misidentifying resource leaks.

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: sysconf() unchecked return value

Fix Coverity bug:

CID 1021259 (#1 of 1): Improper use of negative value
(NEGATIVE_RETURNS)5. negative_returns: sysconf(_SC_PAGESIZE) is passed
to a parameter that cannot be negative.

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

doc: add Python example

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Python agent: do not register twice to same port

It is possible that one of the session daemons left its agent.port
file on the file system, for example when killed with SIGKILL. It
is also common that both those session daemons use the same port for
listening to agent connections. In this case, if one session daemon
is running, but two agent.port files exist, the Python agent would
connect its two threads to the same session daemon, leading to
everything done twice: list shows events twice, tracing records
events twice, etc.

This patch ensures that if two agent.port files are found and have
the same content, only one thread is used.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: potential leaks in error paths

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: double free in liblttng-ust-dl

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: make check in OOT build with absolute path

The previous patch fixed the out of tree build when the configure script
was called with a path relative to the builddir but still failed when
the path was absolute. This works with both.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: elf: leaks on error paths

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

Cleanup: coding style

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

Cleanup: elf: use off_t for offsets, size_t for len

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

Cleanup: eliminate implicit sign-extension

Coverity reported:

CID 1321723 (#1 of 1): Unintended sign extension
(SIGN_EXTENSION)sign_extension: Suspicious implicit sign extension:
elf->ehdr->e_shentsize with type unsigned short (16 bits, unsigned) is
promoted in index * elf->ehdr->e_shentsize to type int (32 bits,
signed), then sign-extended to type unsigned long (64 bits, unsigned).
If index * elf->ehdr->e_shentsize is greater than 0x7FFFFFFF, the upper
bits of the result will all be 1.

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

Fix: elf: NULL pointer dereference

Coverity reported:
CID 1321730 (#1 of 1): Dereference null return value (NULL_RETURNS)15.
dereference: Dereferencing a pointer that might be null _build_id when
calling lttng_ust_read.

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

Fix: add missing ust-elf.h header to dist

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: make check in out of tree build

Use the elf data files from the source dir when running make check in an
out of tree builddir and add the data files to dist.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: old gcc warnings

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

Fix: old gcc warning

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

Fix: remove stale lttng-ust-elf.h from makefile

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

Fix: elf: uninitialized ret

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

Fix: test elf: handle NULL debug file

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

test: elf move constants to top of implementation

Declare them static const.

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

Fix: elf test prog arg checking

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

baddr statedump: remove dependency on file streams

None of the rest of UST used by applications use file streams (only the
sessiond uses a file streams for metadata). Therefore, use file
descriptors directly for baddr statedump.

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

baddr statedump: hold ust lock around allocations

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

Add unit tests for lttng_ust_elf

This adds unit tests for UST's ELF parser. Also included are test ELF
files for multiple architectures (x86, x86_64, armeb, aarch64_be). The
procedure to generate these test files is described in
`tests/ust-elf/README.md`.

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add memory size, build id, and debug link info to statedump and dl

Implement a minimal ELF parser allowing to compute an executable's
in-memory size and to read its build id and debug link info, if any,
at runtime. This is performed during base address statedump, and on
dlopen when using the `liblttng-ust-dl.so` helper.

This adds a `memsz` field to `lttng_ust_statedump:soinfo` and
`lttng_ust_dl:dlopen`. Also adds two events to both providers,
`build_id` and `debug_link`, which are only traced when the
corresponding information is found in the executable file. They can be
matched with the corresponding `soinfo` or `dlopen` via the `baddr`
field shared amongst all the events. Build ID and debug link are
standard methods of identifying and retrieving debug information
corresponding to a specific version of an executable.

The fields `size` and `mtime` from the existing `soinfo` and `dlopen`
events have been removed as they provided no valuable information for
analysis, whereas build ID or debug link allow unambiguous retrieval
of the debug information, and the on-disk `size` is superseded by the
in-memory `memsz`.

Signed-off-by: Antoine Busque <abusque@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: close socket on protocol error, sendmsg MSG_NOSIGNAL

Don't try to keep interacting with sessiond when a protocol error is
detected at the UST application side: this means we cannot trust the
protocol anymore, so there is no reason for keeping the socket open.
For instance, if the application is exiting and we receive a new stream,
we're effectively not reading the stream data, and we return an error.
Unfortunately, the session daemon may try to send us another command,
but we will try interpreting the stream data as a command, which is
invalid.

Also, use MSG_NOSIGNAL flag in the fds recvmsg, so the session daemon
don't get killed with SIGPIPE when it cannot send to the socket due to
connection closed.

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

Cleanup: more descriptive error message

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

Fix: add missing ust lock around objd_table_destroy()

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

Fix: application exit race with pthread cancel

Listener threads can be cancelled with ust lock held, which can hang the
following ust cleanup routine, because tracepoint probe unregister needs
to take the ust lock.

Fix this by disabling pthread cancellation for the entire duration of
the ust lock.

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

Cleanup: configure layout for python agent detection

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

Build: python agent: use setup.py over autoconf

This change provides a valid way of installing the agent. The autoconf
python macro provides the wrong installation path for
python 3 under Debian and Ubuntu due to distro-specific packaging for
python 2.7 and 3.

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Build: add python interpreter used by python agent if built

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Doc: basic lttng ust python agent documentation

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Build: use AM_PATH_PYTHON to resolve python when building agent

The agent can be built against a forced python version by exporting
PYTHON environment variable at configure time.

ex:
$ export PYTHON=python3
$ ./configure --enable-python-agent

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Build: only check if python exists in path

Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update version to 2.8.0-pre

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