Improved bus and device management

6 files changed, 43 insertions, 25 deletions

diff --git a/kernel/features/bus.c b/kernel/features/bus.c
index ad7352f..811ad88 100644
--- a/kernel/features/bus.c
+++ b/kernel/features/bus.c
@@ -93,6 +93,21 @@ static void bus_add_conn(u32 hash, u32 conn)
 	list_add(bus_conns, bus_conn);
 }
 
+static res bus_conn_ready(struct bus_conn *bus_conn)
+{
+	struct bus *bus = bus_find_bus(bus_conn->bus);
+	if (!bus)
+		return -ENOENT;
+
+	u8 ready = 0;
+	if (bus->pid == proc_current()->pid)
+		ready = !stack_empty(bus_conn->in);
+	else
+		ready = !stack_empty(bus_conn->out);
+
+	return ready ? EOK : -EAGAIN;
+}
+
 static res bus_register(const char *name)
 {
 	if (!memory_readable(name))
@@ -236,14 +251,14 @@ static res bus_receive(void *buf, u32 offset, u32 count)
 		struct node *iterator = bus_conns->head;
 		while (iterator) {
 			struct bus_conn *sub_bus = iterator->data;
-			if (sub_bus->bus == bus_owner->hash)
+			if (sub_bus->bus == bus_owner->hash && bus_conn_ready(sub_bus) == EOK)
 				return bus_conn_receive(sub_bus, buf, offset, count);
 
 			iterator = iterator->next;
 		}
 	}
 
-	if (bus_conn)
+	if (bus_conn && bus_conn_ready(bus_conn) == EOK)
 		return bus_conn_receive(bus_conn, buf, offset, count);
 
 	return -EAGAIN;
@@ -286,21 +301,6 @@ static res bus_read(void *buf, u32 offset, u32 count)
 	return bus_receive(buf, offset, count);
 }
 
-static res bus_conn_ready(struct bus_conn *bus_conn)
-{
-	struct bus *bus = bus_find_bus(bus_conn->bus);
-	if (!bus)
-		return -ENOENT;
-
-	u8 ready = 0;
-	if (bus->pid == proc_current()->pid)
-		ready = !stack_empty(bus_conn->in);
-	else
-		ready = !stack_empty(bus_conn->out);
-
-	return ready ? EOK : -EAGAIN;
-}
-
 static res bus_ready(void)
 {
 	struct bus *bus_owner = bus_find_owner(proc_current()->pid);
@@ -312,15 +312,15 @@ static res bus_ready(void)
 		struct node *iterator = bus_conns->head;
 		while (iterator) {
 			struct bus_conn *sub_bus = iterator->data;
-			if (sub_bus->bus == bus_owner->hash)
-				return bus_conn_ready(sub_bus);
+			if (sub_bus->bus == bus_owner->hash && bus_conn_ready(sub_bus) == EOK)
+				return EOK;
 
 			iterator = iterator->next;
 		}
 	}
 
-	if (bus_conn)
-		return bus_conn_ready(bus_conn);
+	if (bus_conn && bus_conn_ready(bus_conn) == EOK)
+		return EOK;
 
 	return -EAGAIN;
 }
diff --git a/kernel/features/dev.c b/kernel/features/dev.c
index ecc3f0c..0e082f9 100644
--- a/kernel/features/dev.c
+++ b/kernel/features/dev.c
@@ -63,6 +63,20 @@ static void dev_remove_group(u32 group)
 		group_id--;
 }
 
+void dev_remove_proc(struct proc *proc)
+{
+	for (u32 dev = DEV_MIN; dev < DEV_MAX; dev++) {
+		struct node *iterator = dev_listeners[dev]->head;
+		while (iterator) {
+			struct dev_listener *listener = iterator->data;
+			struct node *next = iterator->next;
+			if (listener->proc == proc)
+				list_remove(dev_listeners[dev], iterator);
+			iterator = next;
+		}
+	}
+}
+
 CLEAR void dev_add(enum dev_type type, struct dev_dev *dev)
 {
 	assert(dev_type_valid(type) && !dev_mappings[type]);
diff --git a/kernel/features/proc.c b/kernel/features/proc.c
index 70e3666..03f45c9 100644
--- a/kernel/features/proc.c
+++ b/kernel/features/proc.c
@@ -1,6 +1,7 @@
 // MIT License, Copyright (c) 2020 Marvin Borner
 
 #include <assert.h>
+#include <dev.h>
 #include <drivers/cpu.h>
 #include <drivers/gdt.h>
 #include <drivers/timer.h>
@@ -190,6 +191,7 @@ void proc_exit(s32 status)
 		printf("Process didn't leak memory!\n");
 	}
 
+	dev_remove_proc(proc);
 	stack_destroy(proc->messages);
 	list_destroy(proc->memory); // TODO: Decrement memory ref links
 	virtual_destroy_dir(proc->page_dir);
diff --git a/kernel/features/syscall.c b/kernel/features/syscall.c
index 997fa96..16a83d6 100644
--- a/kernel/features/syscall.c
+++ b/kernel/features/syscall.c
@@ -63,10 +63,11 @@ static u32 syscall_handler(u32 esp)
 		break;
 	}
 	case SYS_DEV_READ: {
-		res ready = dev_ready(frame->ebx);
-		if (ready == -EAGAIN) {
+		// TODO: This could be done more elegant (e.g. with better bus design)
+		res ready;
+		while ((ready = dev_ready(frame->ebx)) == -EAGAIN)
 			dev_block(frame->ebx, proc_current());
-		} else if (ready != EOK) {
+		if (ready != EOK) {
 			frame->eax = ready;
 			break;
 		}
diff --git a/kernel/inc/dev.h b/kernel/inc/dev.h
index fc5e424..c824009 100644
--- a/kernel/inc/dev.h
+++ b/kernel/inc/dev.h
@@ -17,6 +17,7 @@ struct dev_dev {
 
 void dev_install(void);
 void dev_add(enum dev_type type, struct dev_dev *dev) NONNULL;
+void dev_remove_proc(struct proc *proc) NONNULL;
 
 // No NONNULL on syscalls
 res dev_control(enum dev_type type, u32 request, void *arg1, void *arg2, void *arg3);
diff --git a/kernel/inc/proc.h b/kernel/inc/proc.h
index b2e5c8b..42ff75d 100644
--- a/kernel/inc/proc.h
+++ b/kernel/inc/proc.h
@@ -66,7 +66,7 @@ void proc_set_quantum(struct proc *proc, u32 value) NONNULL;
 void proc_reset_quantum(struct proc *proc) NONNULL;
 void proc_state(struct proc *proc, enum proc_state state) NONNULL;
 struct proc *proc_make(enum proc_priv priv);
-void proc_make_regs(struct proc *proc);
+void proc_make_regs(struct proc *proc) NONNULL;
 void proc_stack_user_push(struct proc *proc, const void *data, u32 size) NONNULL;
 void proc_stack_kernel_push(struct proc *proc, const void *data, u32 size) NONNULL;