Changeset e06da7e in mainline

Timestamp:

2009-03-07T15:59:32Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

411b6a6

Parents:

b11ee88

Message:

If the server cannot receive a call because it supplied a bad userspace address, the kernel will immediately answer the call with EPARTY.

Location:

kernel/generic

Files:

• include/errno.h (modified) (1 diff)
• src/ipc/sysipc.c (modified) (1 diff)

kernel/generic/include/errno.h

@@ -49 +49 @@
                                  * Used by answerbox to close the connection.
                                  */
-#define EEXISTS         -8      /* Entry already exists */
-#define EBADMEM         -9      /* Bad memory pointer */
-#define ENOTSUP         -10     /* Not supported */
-#define EADDRNOTAVAIL   -11     /* Address not available. */
-#define ETIMEOUT        -12     /* Timeout expired */
-#define EINVAL          -13     /* Invalid value */
-#define EBUSY           -14     /* Resource is busy */
-#define EOVERFLOW       -15     /* The result does not fit its size. */
-#define EINTR           -16     /* Operation was interrupted. */
+#define EPARTY          -8      /* The other party encountered an error when
+                                 * receiving the call.
+                                 */
+#define EEXISTS         -9      /* Entry already exists */
+#define EBADMEM         -10     /* Bad memory pointer */
+#define ENOTSUP         -11     /* Not supported */
+#define EADDRNOTAVAIL   -12     /* Address not available. */
+#define ETIMEOUT        -13     /* Timeout expired */
+#define EINVAL          -14     /* Invalid value */
+#define EBUSY           -15     /* Resource is busy */
+#define EOVERFLOW       -16     /* The result does not fit its size. */
+#define EINTR           -17     /* Operation was interrupted. */
 
 #endif

kernel/generic/src/ipc/sysipc.c

@@ -937 +937 @@
          * copy whole call->data, not only call->data.args */
         if (STRUCT_TO_USPACE(calldata, &call->data)) {
-                /* XXX
-                 * To avoid deadlocks in synchronous calls
-                 * this should be replaced by discarding
-                 * the call and notifying the caller.
+                /*
+                 * The callee will not receive this call and no one else has
+                 * a chance to answer it. Reply with the EPARTY error code.
                  */
+                ipc_data_t saved_data;
+                int saveddata = 0;
+
+                if (answer_need_old(call)) {
+                        memcpy(&saved_data, &call->data, sizeof(call->data));
+                        saveddata = 1;
+                }
+                
+                IPC_SET_RETVAL(call->data, EPARTY);
+                (void) answer_preprocess(call, saveddata ? &saved_data : NULL);
+                ipc_answer(&TASK->answerbox, call);
                 return 0;
         }