fixes

kernel/syscalls/channel.c

@@ -12,8 +12,14 @@
 #include <kernel/usercopy.h>
 
 zn_status_t syscall_channel_create(struct arch_context* ctx) {
-    __user zn_handle_t* end0 = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user zn_handle_t* end1 = (__user zn_handle_t*)ctx->ARCH_CTX_A2;
+    auto flags = (enum zn_channel_flags)ctx->a0;
+    auto end0 = (__user zn_handle_t*)ctx->a1;
+    auto end1 = (__user zn_handle_t*)ctx->a2;
+
+    // Validate flags before doing anything.
+    if (flags & !(ZN_CHANNEL_NONE | ZN_CHANNEL_NONBLOCK)) {
+        return ZN_ERR_INVALID;
+    }
 
     struct channel* ep0;
     struct channel* ep1;
@@ -61,11 +67,11 @@ zn_status_t syscall_channel_create(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_channel_write(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
-    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user void* bytes = (__user void*)ctx->ARCH_CTX_A2;
-    size_t num_handles = ctx->ARCH_CTX_A3;
-    size_t num_bytes = ctx->ARCH_CTX_A4;
+    auto ch_handle = (zn_handle_t)ctx->a0;
+    auto handles = (__user zn_handle_t*)ctx->a0;
+    auto bytes = (__user void*)ctx->a2;
+    size_t num_handles = ctx->a3;
+    size_t num_bytes = ctx->a4;
 
     struct task* current = percpu_get()->sched.current;
 
@@ -95,7 +101,7 @@ zn_status_t syscall_channel_write(struct arch_context* ctx) {
         }
     }
 
-    // Copy and transfer handles (move semantics).
+    // Copy and transfer handles.
     struct namespace_desc* descs = nullptr;
     if (num_handles > 0) {
         if (!handles) {
@@ -155,13 +161,13 @@ zn_status_t syscall_channel_write(struct arch_context* ctx) {
 }
 
 zn_status_t syscall_channel_read(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
-    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->ARCH_CTX_A1;
-    __user void* bytes = (__user void*)ctx->ARCH_CTX_A2;
-    size_t num_handles = ctx->ARCH_CTX_A3;
-    size_t num_bytes = ctx->ARCH_CTX_A4;
-    __user size_t* read_handles = (__user size_t*)ctx->ARCH_CTX_A5;
-    __user size_t* read_bytes = (__user size_t*)ctx->ARCH_CTX_A6;
+    zn_handle_t ch_handle = ctx->a0;
+    __user zn_handle_t* handles = (__user zn_handle_t*)ctx->a1;
+    __user void* bytes = (__user void*)ctx->a2;
+    size_t num_handles = ctx->a3;
+    size_t num_bytes = ctx->a4;
+    __user size_t* read_handles = (__user size_t*)ctx->a5;
+    __user size_t* read_bytes = (__user size_t*)ctx->a6;
 
     struct task* current = percpu_get()->sched.current;
     struct sched_percpu* sched = &percpu_get()->sched;
@@ -183,7 +189,7 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
 
         if (status == ZN_OK) {
             // Copy byte data to userspace.
-            size_t bytes_to_copy = msg->num_bytes < num_bytes ? msg->num_bytes : num_bytes;
+            size_t bytes_to_copy = MIN(msg->num_bytes, num_bytes);
             if (bytes_to_copy > 0 && bytes) {
                 if (!usercopy_write(bytes, msg->data, bytes_to_copy)) {
                     channel_msg_free(msg);
@@ -192,7 +198,7 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
             }
 
             // Transfer handle descriptors into the reader's namespace.
-            size_t handles_to_copy = msg->num_handles < num_handles ? msg->num_handles : num_handles;
+            size_t handles_to_copy = MIN(msg->num_handles, num_handles);
             if (handles_to_copy > 0 && handles) {
                 for (size_t i = 0; i < handles_to_copy; i++) {
                     zn_handle_t new_handle;
@@ -231,13 +237,13 @@ zn_status_t syscall_channel_read(struct arch_context* ctx) {
         if (status == ZN_ERR_BAD_HANDLE)
             return status;
 
-        // Empty but peer alive — block until a message arrives or peer closes.
+        // Block until a message arrives or peer closes.
         sched_block(sched, &ch->waiters);
     }
 }
 
 zn_status_t syscall_channel_wait(struct arch_context* ctx) {
-    zn_handle_t ch_handle = ctx->ARCH_CTX_A0;
+    zn_handle_t ch_handle = ctx->a0;
 
     struct task* current = percpu_get()->sched.current;
     struct sched_percpu* sched = &percpu_get()->sched;