Feat: POSIX signal

kernel/include/process.h

@@ -1,6 +1,8 @@
 #pragma once
 
 #include <stddef.h>
+#include <vector.h>
+#include <signal.h>
 
 typedef struct {
   uint64_t x0, x1;
@@ -38,6 +40,13 @@ typedef struct process {
   void *mem;
   size_t mem_size;
 
+  void *sigstack;
+  size_t sigstack_size;
+
+  bool sigstate[SIGNAL_NUM];
+  int32_t current_signal;
+  signal_handler_t sighandlers[SIGNAL_NUM];
+
   trapframe_t *regs;
 } process_t;
 
@@ -51,3 +60,4 @@ int32_t run_process(uint64_t process);
 process_t *fork_process(const process_t *from);
 
 extern int32_t global_pid_counter;
+extern vector_t *global_processes;