Properly initialise some structures

[ac000]

While tracking down some memory leaks valgrind(1) was highlighting numerous issues. Including the following

==166470== Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
==166470==    at 0x4AE6514: sendmsg (sendmsg.c:28)
==166470==    by 0x42D86C: nxt_sendmsg (nxt_socket_msg.c:32)
==166470==    by 0x4FE6695: nxt_unit_sendmsg (nxt_unit.c:6013)
==166470==    by 0x4FEB6E2: nxt_unit_ready (nxt_unit.c:963)
==166470==    by 0x4FEB6E2: nxt_unit_init (nxt_unit.c:557)
==166470==    by 0x4FEEC56: nxt_php_start (nxt_php_sapi.c:507)
==166470==    by 0x426BA0: nxt_app_setup (nxt_application.c:1029)
==166470==    by 0x403153: nxt_process_do_start (nxt_process.c:718)
==166470==    by 0x4042A3: nxt_process_whoami_ok (nxt_process.c:846)
==166470==    by 0x407A28: nxt_port_rpc_handler (nxt_port_rpc.c:347)
==166470==    by 0x407E42: nxt_port_handler (nxt_port.c:184)
==166470==    by 0x40501B: nxt_port_read_msg_process (nxt_port_socket.c:1271)
==166470==    by 0x4055B3: nxt_port_read_handler (nxt_port_socket.c:778)
==166470==  Address 0x1ffefffc7f is on thread 1's stack
==166470==  in frame #3, created by nxt_unit_init (nxt_unit.c:428)
==166470==  Uninitialised value was created by a stack allocation
==166470==    at 0x4FEABFE: nxt_unit_init (nxt_unit.c:436)

==166470== Syscall param sendmsg(msg.msg_control) points to uninitialised byte(s)
==166470==    at 0x4AE6514: sendmsg (sendmsg.c:28)
==166470==    by 0x42D86C: nxt_sendmsg (nxt_socket_msg.c:32)
==166470==    by 0x4FE6695: nxt_unit_sendmsg (nxt_unit.c:6013)
==166470==    by 0x4FEB6E2: nxt_unit_ready (nxt_unit.c:963)
==166470==    by 0x4FEB6E2: nxt_unit_init (nxt_unit.c:557)
==166470==    by 0x4FEEC56: nxt_php_start (nxt_php_sapi.c:507)
==166470==    by 0x426BA0: nxt_app_setup (nxt_application.c:1029)
==166470==    by 0x403153: nxt_process_do_start (nxt_process.c:718)
==166470==    by 0x4042A3: nxt_process_whoami_ok (nxt_process.c:846)
==166470==    by 0x407A28: nxt_port_rpc_handler (nxt_port_rpc.c:347)
==166470==    by 0x407E42: nxt_port_handler (nxt_port.c:184)
==166470==    by 0x40501B: nxt_port_read_msg_process (nxt_port_socket.c:1271)
==166470==    by 0x4055B3: nxt_port_read_handler (nxt_port_socket.c:778)
==166470==  Address 0x1ffefffc9c is on thread 1's stack
==166470==  in frame #3, created by nxt_unit_init (nxt_unit.c:428)
==166470==  Uninitialised value was created by a stack allocation
==166470==    at 0x4FEABFE: nxt_unit_init (nxt_unit.c:436)

==166690== Syscall param sendmsg(msg.msg_iov[0]) points to uninitialised byte(s)
==166690==    at 0x4AE6514: sendmsg (sendmsg.c:28)
==166690==    by 0x42D871: nxt_sendmsg (nxt_socket_msg.c:32)
==166690==    by 0x4FE6695: nxt_unit_sendmsg (nxt_unit.c:6009)
==166690==    by 0x4FE69C8: nxt_unit_port_send (nxt_unit.c:5939)
==166690==    by 0x4FE8C77: nxt_unit_request_done (nxt_unit.c:3309)
==166690==    by 0x4FEE13B: nxt_php_execute (nxt_php_sapi.c:1257)
==166690==    by 0x4FEE2F1: nxt_php_dynamic_request (nxt_php_sapi.c:1128)
==166690==    by 0x4FEE79E: nxt_php_request_handler (nxt_php_sapi.c:1023)
==166690==    by 0x4FE92AD: nxt_unit_process_ready_req (nxt_unit.c:4846)
==166690==    by 0x4FED1B4: nxt_unit_run_once_impl (nxt_unit.c:4605)
==166690==    by 0x4FED3AE: nxt_unit_run (nxt_unit.c:4548)
==166690==    by 0x4FEEC2A: nxt_php_start (nxt_php_sapi.c:514)
==166690==  Address 0x1ffeffea5f is on thread 1's stack
==166690==  in frame #3, created by nxt_unit_port_send (nxt_unit.c:5907)
==166690==  Uninitialised value was created by a stack allocation
==166690==    at 0x4FE8C05: nxt_unit_request_done (nxt_unit.c:3255)

These are down to structures being passed around with uninitialised members.

(Note: There are some more similar cases but these commits resolve the above while being obviously correct and good in their own right).

The first commit Fully initialise nxt_port_msg_t msg structures resolves the first and last of the above alerts, by fully empty-initialising the msg structure, this then negates the need to further initialise some members to 0.

The second commit Fully initialise the oob struct in nxt_socket_msg_oob_init() resolves the middle of the above alerts, by fully empty-initialising the oob structure.

The following changes since commit 3b18ffe09370573f81220fda5e924124fcf8f0df:

  tests: Fix TLS tests with Python 3.13 (2025-03-27 23:39:32 +0000)

are available in the Git repository at:

  [email protected]:ac000/unit.git struct-init

for you to fetch changes up to 0c59a033b6fa5c02c98128cef9492264d489a32f:

  Fully initialise the oob struct in nxt_socket_msg_oob_init() (2025-04-09 17:46:14 +0100)

----------------------------------------------------------------
Andrew Clayton (2):
      Fully initialise nxt_port_msg_t msg structures
      Fully initialise the oob struct in nxt_socket_msg_oob_init()

 src/nxt_socket_msg.h |  2 ++
 src/nxt_unit.c       | 12 ++----------
 2 files changed, 4 insertions(+), 10 deletions(-)

[ac000]

Rebased with master

$ git range-diff 0c59a033...89149c06
-:  -------- > 1:  f2e97bf3 rust: Update rust crates
-:  -------- > 2:  0cbdcb15 pkg/contrib: Bump wasmtime to 31.0.0
1:  1f317c17 = 3:  326f42a5 Fully initialise nxt_port_msg_t msg structures
2:  0c59a033 = 4:  89149c06 Fully initialise the oob struct in nxt_socket_msg_oob_init()

[ac000]

Thanks Zhidao!