Merge pull request #1580 from Kijewski/thread_get

core: add `thread_get()`

core/include/thread.h

@@ -79,6 +79,16 @@ kernel_pid_t thread_create(char *stack,
                   void *(*function)(void *arg),
                   void *arg,
                   const char *name);
+
+/**
+ * @brief       Retreive a thread control block by PID.
+ * @details     This is a bound-checked variant of accessing `sched_threads[pid]` directly.
+ *              If you know that the PID is valid, then don't use this function.
+ * @param[in]   pid   Thread to retreive.
+ * @return      `NULL` if the PID is invalid or there is no such thread.
+ */
+volatile tcb_t *thread_get(kernel_pid_t pid);
+
 /**
  * @brief Returns the status of a process
  *

core/thread.c

@@ -37,22 +37,24 @@ inline kernel_pid_t thread_getpid(void)
     return sched_active_thread->pid;
 }
 
-int thread_getstatus(kernel_pid_t pid)
+volatile tcb_t *thread_get(kernel_pid_t pid)
 {
-    if (sched_threads[pid] == NULL) {
-        return STATUS_NOT_FOUND;
+    if ((pid != KERNEL_PID_UNDEF) && (0 <= pid) && (pid < MAXTHREADS)) {
+        return sched_threads[pid];
     }
+    return NULL;
+}
 
-    return sched_threads[pid]->status;
+int thread_getstatus(kernel_pid_t pid)
+{
+    volatile tcb_t *t = thread_get(pid);
+    return t ? t->status : STATUS_NOT_FOUND;
 }
 
 const char *thread_getname(kernel_pid_t pid)
 {
-    if (sched_threads[pid] == NULL) {
-        return NULL;
-    }
-
-    return sched_threads[pid]->name;
+    volatile tcb_t *t = thread_get(pid);
+    return t ? t->name : NULL;
 }
 
 void thread_sleep(void)