From: Matthias Kruk <m@m10k.eu>
Date: Sat, 4 Apr 2020 15:57:57 +0000 (+0900)
Subject: kernel/core: Make mailbox_get() return -EINTR if the call to sem_wait() failed
X-Git-Url: https://git.corax.cc/?a=commitdiff_plain;h=d416bbc58f70e557873bff6440d7851eaad97f32;p=corax

kernel/core: Make mailbox_get() return -EINTR if the call to sem_wait() failed
---

diff --git a/kernel/core/mailbox.c b/kernel/core/mailbox.c
index 1167995..1510e02 100644
--- a/kernel/core/mailbox.c
+++ b/kernel/core/mailbox.c
@@ -94,16 +94,18 @@ int mailbox_get(struct mailbox *mbox, void **dst)
 		 * This function always succeeds, so we don't have to
 		 * check its return value.
 		 */
-		sem_wait(&(mbox->mb_rsem));
+		ret_val = sem_wait(&(mbox->mb_rsem));
 
-		/* retrieve the message */
-		*dst = mbox->mb_msg;
-
-		/*
-		 * Rendevouz with the sender: Let them know we have
-		 * received their message.
-		 */
-		ret_val = sem_post(&(mbox->mb_ssem));
+		if(!ret_val) {
+			/* retrieve the message */
+			*dst = mbox->mb_msg;
+
+			/*
+			 * Rendevouz with the sender: Let them know we have
+			 * received their message.
+			 */
+			ret_val = sem_post(&(mbox->mb_ssem));
+		}
 	}
 
 	return(ret_val);
diff --git a/kernel/core/mailbox.h b/kernel/core/mailbox.h
index b5c50be..1f585d9 100644
--- a/kernel/core/mailbox.h
+++ b/kernel/core/mailbox.h
@@ -148,10 +148,14 @@ int mailbox_put(struct mailbox*, void*);
  *  message can be retrieved. The sending and receiving tasks will
  *  rendevouz during the message transmission, meaning that the sender
  *  will wait for the message to be retrieved by a receiving task.
+ *  If a signal is delivered to the task while it is waiting for a
+ *  message to be put into the mailbox, this function will return early,
+ *  leaving the mailbox unmodified.
  *
  * RETURN VALUE
  *           0 A message was successfully retrieved from the mailbox
  *     -EINVAL Invalid mailbox specified
+ *      -EINTR The function call was interrupted by a signal
  *  -EOVERFLOW An overflow occured during the rendevouz. This error
  *             means that the mailbox was overwritten with invalid
  *             data due to a kernel bug