From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Alperen Erkan Date: Sat, 25 Jul 2026 00:00:00 +0300 Subject: [PATCH] Revert erroneous changes to ipc_mqueue_send The prior patch to ipc_mqueue.c introduced no genuine fix and several regressions, as pointed out in review: - Added an author/copyright claim for a handful of modified lines, which does not establish authorship. - Replaced assert(IP_VALID(port)) with a soft runtime check; the port is expected to already be validated by the caller, so this only hid a caller-side bug instead of catching it. - Added a NULL-kmsg guard for a value that is never NULL at this call site, for the same reason. - Introduced IPC_MQUEUE_HARD_LIMIT and used it to let MACH_SEND_ALWAYS sends past port->ip_qlimit, silently weakening the existing queue-limit enforcement. - Reformatted large parts of the function from tabs to spaces, mangling the diff and making the change hard to review. - Added a no-op reassignment (self->ith_state = MACH_MSG_SUCCESS) and a dead-code state clear before the switch, neither of which changes behavior. - Left a non-English comment in the code. This restores ipc_mqueue_send to its original, correct form. No functional change is being proposed for this file. --- gnumach/ipc/ipc_mqueue.c | 88 ++++++++++++++++------------------------------- 1 file changed, 30 insertions(+), 58 deletions(-) --- a/gnumach/ipc/ipc_mqueue.c 2026-07-25 08:14:49.874356085 +0000 +++ b/gnumach/ipc/ipc_mqueue.c 2026-07-25 08:14:49.875967700 +0000 @@ -27,11 +27,11 @@ * the rights to redistribute these changes. */ /* - * File: ipc/ipc_mqueue.c - * Author: Rich Draves / Alperen ERKAN - * Date: 2026 + * File: ipc/ipc_mqueue.c + * Author: Rich Draves + * Date: 2026 * - * Functions to manipulate IPC message queues. + * Functions to manipulate IPC message queues. */ #include @@ -51,12 +51,6 @@ #include #include -/* - * An absolute message queue upper limit to prevent OOM and memory exhaustion. - */ -#define IPC_MQUEUE_HARD_LIMIT 65536 - - /* * Routine: ipc_mqueue_init * Purpose: @@ -159,8 +153,6 @@ /* * Routine: ipc_mqueue_send - * Author : Alperen ERKAN - * 2026 * Purpose: * Send a message to a port. The message holds a reference * for the destination port in the msgh_remote_port field. @@ -185,16 +177,8 @@ { ipc_port_t port; - /* Defensive C: Checking the incoming message object and destination port */ - if (kmsg == IKM_NULL) { - return MACH_SEND_INVALID_DATA; - } - port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port; - - if (!IP_VALID(port)) { - return MACH_SEND_INVALID_DEST; - } + assert(IP_VALID(port)); ip_lock(port); @@ -243,17 +227,17 @@ } /* - * Don't block if: - * 1) We're under the queue limit. - * 2) Caller used MACH_SEND_ALWAYS but we are under the hard safety limit. - * 3) Message is sent to a send-once right. - */ - - if ((port->ip_msgcount < port->ip_qlimit) || - ((option & MACH_SEND_ALWAYS) && (port->ip_msgcount < IPC_MQUEUE_HARD_LIMIT)) || - (MACH_MSGH_BITS_REMOTE(kmsg->ikm_header.msgh_bits) == - MACH_MSG_TYPE_PORT_SEND_ONCE)) - break; + * Don't block if: + * 1) We're under the queue limit. + * 2) Caller used the MACH_SEND_ALWAYS internal option. + * 3) Message is sent to a send-once right. + */ + + if ((port->ip_msgcount < port->ip_qlimit) || + (option & MACH_SEND_ALWAYS) || + (MACH_MSGH_BITS_REMOTE(kmsg->ikm_header.msgh_bits) == + MACH_MSG_TYPE_PORT_SEND_ONCE)) + break; /* must block waiting for queue to clear */ @@ -272,53 +256,49 @@ ipc_thread_enqueue(&port->ip_blocked, self); self->ith_state = MACH_SEND_IN_PROGRESS; - ip_unlock(port); + ip_unlock(port); counter(c_ipc_mqueue_send_block++); thread_block(thread_no_continuation); ip_lock(port); - + /* why did we wake up? */ - if (self->ith_state == MACH_MSG_SUCCESS) { - self->ith_state = MACH_MSG_SUCCESS; // veya temiz durum sıfırlaması - continue; - } - assert(self->ith_state == MACH_SEND_IN_PROGRESS); - - /* take ourselves off blocked queue under port lock */ - ipc_thread_rmqueue(&port->ip_blocked, self); - - /* [DEFENSIVE]: Clear state to prevent stale status reuse */ - self->ith_state = MACH_MSG_SUCCESS; - - /* - * Thread wakeup-reason field tells us why - * the wait was interrupted. - */ - - switch (self->ith_wait_result) { - case THREAD_INTERRUPTED: - /* send was interrupted - give up */ - - ip_unlock(port); - return MACH_SEND_INTERRUPTED; - - case THREAD_TIMED_OUT: - /* timeout expired */ - - assert(option & MACH_SEND_TIMEOUT); - time_out = 0; - break; + if (self->ith_state == MACH_MSG_SUCCESS) + continue; + assert(self->ith_state == MACH_SEND_IN_PROGRESS); + + /* take ourselves off blocked queue */ + + ipc_thread_rmqueue(&port->ip_blocked, self); + + /* + * Thread wakeup-reason field tells us why + * the wait was interrupted. + */ + + switch (self->ith_wait_result) { + case THREAD_INTERRUPTED: + /* send was interrupted - give up */ + + ip_unlock(port); + return MACH_SEND_INTERRUPTED; + + case THREAD_TIMED_OUT: + /* timeout expired */ + + assert(option & MACH_SEND_TIMEOUT); + time_out = 0; + break; - case THREAD_RESTART: - default: + case THREAD_RESTART: + default: #if MACH_ASSERT - assert(!"ipc_mqueue_send: unexpected thread wakeup result"); + assert(!"ipc_mqueue_send"); #else - panic("ipc_mqueue_send"); + panic("ipc_mqueue_send"); #endif - } - } + } + } if (kmsg->ikm_header.msgh_bits & MACH_MSGH_BITS_CIRCULAR) { ip_unlock(port); -- 2.43.0