Add dev_delhandle() syscall to delete a device handle from process resources

kernel/syscall/dev.c

@@ -135,3 +135,21 @@ int32_t SYSCALL4(sys_dev_cmd, dev1, cmd1, argbuf1, len1) {
 done:
   return ret;
 }
+
+int32_t SYSCALL1(sys_dev_delhandle, dev1) {
+  uint64_t *devh = (uint64_t *)dev1;
+  int32_t ret = E_OK;
+
+  if (devh == NULL) {
+    return E_NOMEMORY;
+  }
+
+  spinlock_acquire(&PROCS.spinlock);
+  Proc *proc = NULL;
+  LL_FINDPROP(PROCS.procs, proc, pid, _caller_pid);
+  spinlock_release(&PROCS.spinlock);
+
+  proc->devs[*devh] = NULL;
+
+  return ret;
+}

kernel/syscall/dev.h

@@ -9,5 +9,6 @@ int32_t SYSCALL2(sys_dev_gethandle, dev1, devname1);
 int32_t SYSCALL0(sys_dev_listsize);
 int32_t SYSCALL2(sys_dev_stat, devstat1, idx1);
 int32_t SYSCALL4(sys_dev_cmd, dev1, cmd1, argbuf1, len1);
+int32_t SYSCALL1(sys_dev_delhandle, dev1);
 
 #endif // SYSCALL_DEV_H_

kernel/syscall/syscall.c

@@ -64,6 +64,7 @@ SyscallFn SYSCALL_TABLE[SYSCALLS_MAX] = {
   [SYS_DEV_LISTSIZE]  = &sys_dev_listsize,
   [SYS_DEV_STAT]      = &sys_dev_stat,
   [SYS_DEV_CMD]       = &sys_dev_cmd,
+  [SYS_DEV_DELHANDLE] = &sys_dev_delhandle,
 
   [SYS_TIME]    = &sys_time,
 };