Feat: POSIX signal

kernel/lib/signal.c

@@ -0,0 +1,59 @@
+#include <signal.h>
+#include <logger.h>
+#include <string.h>
+#include <process.h>
+#include <thread.h>
+#include <kmalloc.h>
+#include <interrupt.h>
+#include <exec.h>
+
+static inline
+void _sighandler_wrapper(signal_handler_t handler)
+{
+  handler();
+  asm volatile(
+    "mov x8, #10" ENDL
+    "svc 0"
+    ::: "x8"
+  );
+}
+
+static inline
+void _sigkill_default_handler()
+{
+  thread_t *th = get_current();
+  th->status = THREAD_STATUS_ZOMBIE;
+}
+
+void run_signal(int32_t SIGNAL)
+{
+  LOG("run_signal"); DEBUG_SIGNAL(SIGNAL);
+  process_t *process = get_current()->process;
+  process->current_signal = SIGNAL;
+  trapframe_t *regs = kmalloc(sizeof(trapframe_t));
+  memcpy(regs, process->regs, sizeof(trapframe_t));
+
+  if (!process->sighandlers[SIGNAL]) {
+    switch (SIGNAL) {
+    case SIGKILL:
+      _sigkill_default_handler();
+      break;
+    default:
+      LOG("No default handler for this signal"); DEBUG_SIGNAL(SIGNAL);
+      return;
+    }
+  }
+
+  *regs = (trapframe_t){
+    .x0 = (uint64_t)process->sighandlers[SIGNAL],
+    .elr_el1 = (uint64_t)_sighandler_wrapper,
+    .sp_el0 = ((uint64_t)process->sigstack + process->sigstack_size - 64),
+  };
+
+  disable_interrupt();
+  process->current_signal = 0x0;
+  process->sigstate[SIGNAL] = false;
+  user_exec(regs);
+
+  __builtin_unreachable();
+}