pretty print: do not print 2 levels of brackets for variant

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

pretty print tracer: use { } for structures and fields

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

pretty print tracer: add missing comma in caller printout

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

pretty-print tracer: cleanup dynamic {} and remove caller addr

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

Fix: tracer: utf16/32 gather types handling

tracer_convert_string_to_utf8 should return the size of the input
(including null terminator) rather than the size of the utf8 output.

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

Update rfc

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

Rename rfc-libside.txt to rfc-side-abi.txt

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

Update libside RFC

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

Update libside rfc

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

Add libside RFC

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

fix: handle EINTR correctly in get_cpu_mask_from_sysfs

If the read() in get_cpu_mask_from_sysfs() fails with EINTR, the code is
supposed to retry, but the while loop condition has (bytes_read > 0),
which is false when read() fails with EINTR. The result is that the code
exits the loop, having only read part of the string.

Use (bytes_read != 0) in the while loop condition instead, since the
(bytes_read < 0) case is already handled in the loop.

Original fix in liburcu from Benjamin Marzinski <bmarzins@redhat.com>:

  commit 9922f33e2986 ("fix: handle EINTR correctly in get_cpu_mask_from_sysfs")

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

side: Introduce caller address

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

side: explicit statedump request key

Make the statedump request key explicit rather than hiding it as a
Thread-Local Storage variable within libside. It's type is still opaque
to the application (void *), but this allows schemes where the statedump
callbacks are not required to emit statedump events from the same
thread: it can pass the statedump_request_key to another thread
responsible for emitting those events.

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

rcu: Update following librseq public API updates

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

Cleanup function argument alignment

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

Implement side_cpu_relax for x86

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

Document application fork/clone vs statedump locking limitations

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

Handle statedump agent thread state across fork

Implement pthread_atfork handlers to deal with statedump agent thread
state across fork.

For glibc, this requires glibc 2.24 or more recent.

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

Implement agent thread wakeup scheme with pthread cond var

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

Implement agent thread

Currently uses 1 second polling for state. To be replaced by a proper
wait/wakeup.

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

list: fix safe list iteration

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

Statedump improvements

- Introduce polling vs agent thread statedump callbacks,
- Use uint64_t for tracer key.

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

Extend statedump API

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

Introduce side ptrace hook

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

Use RCU for statedump

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

Add rculist

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

Introduce list_types.h

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

Implement statedump unit test

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

Implement statedump request notifications

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

Use TLS variable for key state

Keep this hidden from the application.

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

Add "key" to callback registration

This is in preparation to support the state-dump feature.

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

Update gitignore

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

Remove backup file

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

Add indirection for visitor arguments

In order to keep the argument vector const, add an indirection for
visitor arguments to a non-const area of memory, which is clearly
documented as modified by libside.

Add a "cached_arg" placeholder pointer to the visitor structures.

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

Implement 128-bit integer support

TODO in tracer example: Implement 128-bit integer with len_bits != 128
or nonzero offset_bit.

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

API: Add 128-bit integer support

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

Add __int128 support

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

Integer 128 split byte order helpers

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

Revert "Remove const on all side_arg"

This reverts commit 511ee756cf8aa9259489b4386feb2911bb58c20a.

Re-introduce constness of side_arg to ensure that side_calls are pure.

This will facilitate integration with various runtimes and eliminate
corner-cases.

We plan on copying side argument vectors within libside when translating
from visitor types to flattened types.

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

Use zero-sized array as last field of event description

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

Add u128/s128 integer to ABI

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

API: Intitialize arg flags to 0

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

ABI: Introduce incomplete type flag

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

Remove const on all side_arg

Remove const from side_arg and types containing a side_arg so they can
be altered by libside for visitor caching.

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

Remove packed from visitor ABI

The visitor ABI is a contract between instrumented applications and
userspace tracers only, and follows C calling convention, so packing
those data structures serve no purpose.

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

Move side_callback to libside internals

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

Remove packed from struct side_callback

This is internal to libside.

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

Rename side state "p" field to "parent"

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

Move nr_callbacks to event state

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

Use uintptr_t for enabled state to eliminate partial register stalls

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

side event state does not need side_ptr_t

This is not relevant for tracers: only between instrumented application
and libside.

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

Remove event state abi version validation from tracer

This is internal to libside.

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

Document ABI extensibility schemes

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

Move ABI headers under side/abi/

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

Remove unneeded fwd declaration

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

Split trace.h into API/ABI sub-headers

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

Introduce event state ABI version

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

Extensible struct side_event_state

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

Document side_ptr_get can be used as r or lvalue

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

Update side_ptr_t macros

Allow fetching a single 32-bit pointer on 32-bit architectures.

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

Use structure size and version for event description extensibility

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

Update gitignore to ignore editor .swp files

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

Remove bogus swap file

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

tracer: Validate number of known event types

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

Add nr_side_type_label and nr_side_attr_type event description fields

Allow tracers to discover whether they know about all field types
present when the event instrumentation was compiled.

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

enum side_error is actually used

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

Enforce ABI size checks

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

side.c: Use assert to validate flags

Flag validation is redundant with the logic already verified on
registration. Therefore, use an assertion, which can be compiled-out
when performance matters.

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

trace.h: Cleanup: Add missing () around macro parameter

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

Use event state as argument to call fast path

Eliminate the need to load the event description cache lines (to load a
pointer to the event state) on the fast path by passing a pointer to the
event state as argument to the call.

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

trace.h: Move back nr_callbacks to event description

nr_callbacks is not used on the fast path, therefore move it back to the
event description to optimize cache density of the event state enabled
flags.

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

trace.h: Use side_enum_t for enum side_type_label_byte_order

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

Comment that side_error enum is unused

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

trace.h: Use side_enum_t for side_loglevel enum

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

trace.h: Use side_enum_t for side_attr_type enum

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

trace.h: Use side_enum_t for enum side_type_label

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

macros.h: Implement side_enum_t

side_enum_t allows defining fixed-sized enumerations while preserving
typing information.

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

trace.h: Use side_ptr_t for event description

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

Use side_ptr_t for dynamic arguments

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

trace.h: Use side_ptr_t for gather args

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

trace.h: Use side_ptr_t for string_value pointer

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

trace.h: Use side_ptr_t for stack-copy compound type args

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

trace.h: Use side_ptr_t for additional fields

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

Use side_ptr_t for enum mappings pointers

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

Use side_ptr_t for other attribute pointers

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

Fix: accept variable list of arguments from SIDE_PTR_INIT

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

Use side_ptr_t in side_type_bool

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

Use SIDE_PTR_INIT in side_type_raw_string

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

Use side_ptr_t for side_type_null attr pointer

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

macros.h: Introduce SIDE_PTR_INIT helper

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

Convert side_type_raw_string pointer to side_ptr

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

macros.h: Introduce side_ptr macros

The side_ptr macros allow defining a pointer type which is suitable
for use by 32-bit and 64-bit kernels without compatibility code,
while preserving information about the pointer type.

Those pointers are stored as 64-bit integers, and the type of the
actual pointer is kept alongside with the 64-bit pointer value in a
0-len array within a union.

uintptr_t will fit within a uint64_t except on architectures with
128-bit pointers. This provides fixed-size pointers on architectures
with pointer size of 64-bit or less. Architectures with larger
pointer size will have to handle the ABI offset specifics explicitly.

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

Cleanup macros.h

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

Extract callbacks and enabled state to non-packed structure

Atomic load/store should be performed on non-packed structure.

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

Fix clang warning

Clang issues a warning about what we are really intending to do. Use an
explicit type as argument to sizeof().

tracer.c:1152:28: warning: 'memcpy' call operates on objects of type 'const char' while the size is based on a different type 'const char *' [-Wsizeof-pointer-memaccess]
                memcpy(&ptr, ptr, sizeof(ptr));
                             ~~~         ^~~
tracer.c:1152:28: note: did you mean to provide an explicit length?
                memcpy(&ptr, ptr, sizeof(ptr));
                                         ^~~
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

unit tests: Use default empty attributes

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

demo unit test: Use default attribute list

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

trace.h: Implement optional attribute lists

Attribute lists are typically empty. Implement support for optional last
macro arguments generating empty attribute lists.

Suggested-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

macros.h: Implement SIDE_PARAM_SELECT_ARG1

Implement the SIDE_PARAM_SELECT_ARG1 macro which allows side macros to
support optional last argument. This is useful for attribute lists,
which are typically empty.

Suggested-by: Olivier Dion <odion@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add demo unit test

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