Fixed a mutex leak in the C API.

In nxt_unit_create() we could leak a mutex created in
nxt_unit_ctx_init().

This could happen if nxt_unit_ctx_init() succeeded but later on we
bailed out of nxt_unit

Fixed a mutex leak in the C API.

In nxt_unit_create() we could leak a mutex created in
nxt_unit_ctx_init().

This could happen if nxt_unit_ctx_init() succeeded but later on we
bailed out of nxt_unit_create(), we would destroy the mutex created in
nxt_unit_create() but not the one created in nxt_unit_ctx_init().

Reorder things so that we do the call to nxt_unit_create() after all the
other checks so if it fails we don't leak the mutex it created.

Co-developed-by: Andrew Clayton <a.clayton@f5.com>
Signed-off-by: Andrew Clayton <a.clayton@f5.com>
Signed-off-by: Alex Colomar <a.colomar@f5.com>

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Unit: removed a useless assignment.

As was pointed out by the cppcheck[0] static code analysis utility there
was a useless assignment in nxt_unit_request_read(). The size parameter
is passed in by v

Unit: removed a useless assignment.

As was pointed out by the cppcheck[0] static code analysis utility there
was a useless assignment in nxt_unit_request_read(). The size parameter
is passed in by value and was being modified without being used again.

[0]: https://cppcheck.sourceforge.io/

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Unit: avoided needlessly setting lib in nxt_unit_shm_open().

As was pointed out by the cppcheck[0] static code analysis utility, lib
was being set in nxt_unit_shm_open() regardless of platform when

Unit: avoided needlessly setting lib in nxt_unit_shm_open().

As was pointed out by the cppcheck[0] static code analysis utility, lib
was being set in nxt_unit_shm_open() regardless of platform when in fact
it's only used when (NXT_HAVE_MEMFD_CREATE || NXT_HAVE_SHM_OPEN).

Move the variable declaration & definition to be within the

#if (NXT_HAVE_MEMFD_CREATE || NXT_HAVE_SHM_OPEN)

block.

[0]: https://cppcheck.sourceforge.io/

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Constified numerous function parameters.

As was pointed out by the cppcheck[0] static code analysis utility we
can mark numerous function parameters as 'const'. This acts as a hint to
the compiler a

Constified numerous function parameters.

As was pointed out by the cppcheck[0] static code analysis utility we
can mark numerous function parameters as 'const'. This acts as a hint to
the compiler about our intentions and the compiler will tell us when we
deviate from them.

[0]: https://cppcheck.sourceforge.io/

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Removing unused tracking fields and functions.

The message tracking is unused since 1d84b9e4b459 commit.

This fixes the issue found by Coverity (CID 376263).

Fixed indentation.

Some lines (incorrectly) had an indentation of 3 or 5, or 7 or 9,
or 11 or 13, or 15 or 17 spaces instead of 4, 8, 12, or 16. Fix them.

Found with:

$ find src -type f | xargs g

Fixed indentation.

Some lines (incorrectly) had an indentation of 3 or 5, or 7 or 9,
or 11 or 13, or 15 or 17 spaces instead of 4, 8, 12, or 16. Fix them.

Found with:

$ find src -type f | xargs grep -n '^ [^ ]';
$ find src -type f | xargs grep -n '^ [^ *]';
$ find src -type f | xargs grep -n '^ [^ ]';
$ find src -type f | xargs grep -n '^ [^ *]';
$ find src -type f | xargs grep -n '^ [^ +]';
$ find src -type f | xargs grep -n '^ [^ *+]';
$ find src -type f | xargs grep -n '^ [^ +]';
$ find src -type f | xargs grep -n '^ [^ *+]';

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Fixing uninitialized structure field.

Port's "data" field may be used by application and thus need to be set to NULL.
The issue was introduced in the f8a0992944df commit.

Found by Coverity (CID 374

Fixing uninitialized structure field.

Port's "data" field may be used by application and thus need to be set to NULL.
The issue was introduced in the f8a0992944df commit.

Found by Coverity (CID 374352).

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Sending shared port to application prototype.

Application process started with shared port (and queue) already configured.
But still waits for PORT_ACK message from router to start request processin

Sending shared port to application prototype.

Application process started with shared port (and queue) already configured.
But still waits for PORT_ACK message from router to start request processing
(so-called "ready state").

Waiting for router confirmation is necessary. Otherwise, the application may
produce response and send it to router before the router have the information
about the application process. This is a subject of further optimizations.

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Fixed possible access to an uninitialized field.

The "recv_msg.incoming_buf" is checked after jumping to the "done" label
if nxt_socket_msg_oob_get_fds() returns an error.

Also moved initialization

Fixed possible access to an uninitialized field.

The "recv_msg.incoming_buf" is checked after jumping to the "done" label
if nxt_socket_msg_oob_get_fds() returns an error.

Also moved initialization of "port_msg" near to its first usage.

Found by Coverity (CID 373899).

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Introducing application prototype processes.

Introduced SCM_CREDENTIALS / SCM_CREDS in the socket control msgs.

Moving request limit control to libunit.

Introducting application graceful stop. For now only used when application
process reach request limit value.

This closes #585 issue on GitHub.

Fixing warnings on Solaris.

pthread_t on Solaris is an integer type with size not equal to pointer size.
To avoid warnings, type casts to and from pointer needs to be done via
uintptr_t type.

This

Fixing warnings on Solaris.

pthread_t on Solaris is an integer type with size not equal to pointer size.
To avoid warnings, type casts to and from pointer needs to be done via
uintptr_t type.

This change originally proposed by Juraj Lutter <juraj@lutter.sk>.

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Libunit: processing single port message.

This partially reverts the optimisation introduced in 1d84b9e4b459 to avoid an
unpredictable block in nxt_unit_process_port_msg(). Under high load, this
fun

Libunit: processing single port message.

This partially reverts the optimisation introduced in 1d84b9e4b459 to avoid an
unpredictable block in nxt_unit_process_port_msg(). Under high load, this
function may never return control to its caller, and the external event loop
(in Node.js and Python asyncio) won't be able to process other scheduled
events.

To reproduce the issue, two request processing types are needed: 'fast' and
'furious'. The 'fast' one simply returns a small response, while the 'furious'
schedules asynchronous calls to external resources. Thus, if Unit is subjected
to a large amount of 'fast' requests, the 'furious' request processing freezes
until the high load ends.

The issue was found by Wu Jian Ping (@wujjpp) during Node.js stream
implementation discussion and relates to PR #502 on GitHub.

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Libunit: fixed shared memory waiting.

The nxt_unit_ctx_port_recv() function may return the NXT_UNIT_AGAIN code, in
which case an attempt to reread the message should be made.

The issue was reproduc

Libunit: fixed shared memory waiting.

The nxt_unit_ctx_port_recv() function may return the NXT_UNIT_AGAIN code, in
which case an attempt to reread the message should be made.

The issue was reproduced in load testing with response sizes 16k and up.
In the rare case of a NXT_UNIT_AGAIN result, a buffer of size -1 was processed,
which triggered a 'message too small' alert; after that, the app process was
terminated.

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Limiting app queue notifications count in socket.

Under high load, a queue synchonization issue may occur, starting from the
steady state when an app queue message is dequeued immediately after it h

Limiting app queue notifications count in socket.

Under high load, a queue synchonization issue may occur, starting from the
steady state when an app queue message is dequeued immediately after it has been
enqueued. In this state, the router always puts the first message in the queue
and is forced to notify the app about a new message in an empty queue using a
socket pair. On the other hand, the application dequeues and processes the
message without reading the notification from the socket, so the socket buffer
overflows with notifications.

The issue was reproduced during Unit load tests. After a socket buffer
overflow, the router is unable to notify the app about a new first message.
When another message is enqueued, a notification is not required, so the queue
grows without being read by the app. As a result, request processing stops.

This patch changes the notification algorithm by counting the notifications in
the pipe instead of getting the number of messages in the queue.

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Libunit: improved error logging around initialization env variable.

Libunit: fixing read buffer leakage.

If shared queue is empty, allocated read buffer should be explicitly
released.

Found by Coverity (CID 363943).
The issue was introduced in f5ba5973a0a3.

Libunit: fixing read buffer allocations on exit.

Libunit: closing active requests on quit.

Libunit: making minor tweaks.

Removing unnecessary context operations from shared queue processing loop.
Initializing temporary queues only when required.

Go: removing C proxy functions and re-using goroutines.

Libunit: fixing racing condition in request struct recycling.

The issue occurred under highly concurrent request load in Go applications.
Such applications are multi-threaded but use a single libuni

Libunit: fixing racing condition in request struct recycling.

The issue occurred under highly concurrent request load in Go applications.
Such applications are multi-threaded but use a single libunit context; any
thread-safe code in the libunit context is only required for Go applications.

As a result of improper request state reset, the recycled request structure was
recovered in the released state, so further operations with this request
resulted in 'response already sent' warnings. However, the actual response was
never delivered to the router and the client.

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Libunit: fixing racing condition for port add / state change.

The issue only occurred in Go applications because "port_send" is overloaded
only in Go. To reproduce it, send multiple concurrent requ

Libunit: fixing racing condition for port add / state change.

The issue only occurred in Go applications because "port_send" is overloaded
only in Go. To reproduce it, send multiple concurrent requests to the
application after it has initialised. The warning message "[unit] [go] port
NNN:dd not found" is the first visible aspect of the issue; the second and more
valuable one is a closed connection, an error response, or a hanging response to
some requests.

When the application starts, it is unaware of the router's worker thread ports,
so it requests the ports from the router after receiving requests from the
corresponding router worker threads. When multiple requests are processed
simultaneously, the router port may be required by several requests, so request
processing starts only after the application receives the required port
information. The port should be added to the Go port repository after its
'ready' flag is updated. Otherwise, Unit may start processing some requests and
use the port before it is in the repository.

The issue was introduced in changeset 78836321a126.

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Libunit: improving logging consistency.

Debug logging depends on macros defined in nxt_auto_config.h.