Changeset 2799 for trunk

Timestamp:

Aug 28, 2006, 4:01:58 AM (19 years ago)

Author:

bird

Message:

Lock the thread database before forking. Fixes #102. (from 0.6)

Location:

trunk/libc

Files:

• ChangeLog.LIBC (modified) (1 diff)
• src/libc/process/thread_internals.c (modified) (2 diffs)

trunk/libc/ChangeLog.LIBC

@@ -5 +5 @@
 2006-08-27: knut st. osmundsen <bird-gccos2-spam@anduin.net>
     - libc:
+        o Lock the thread database before forking. Fixes #102. (from 0.6)
         o Fixed log problem in fork() child. Fixes #119. (from 0.6)
         o Corrected DosSetFHState mask. Fixes #118.

trunk/libc/src/libc/process/thread_internals.c

@@ -63 +63 @@
 /** Number of threads in the zombie thread database. (Protected gmtxThrdDB.) */
 static unsigned         gcThrdDBZombies;
+/** Fork cleanup indicator. */
+static unsigned         gfForkCleanupDone;
 
 /** Head of the thread termination callback list. */
@@ -527 +529 @@
     LIBCLOG_RETURN_VOID();
 }
+
+
+#undef  __LIBC_LOG_GROUP
+#define __LIBC_LOG_GROUP    __LIBC_LOG_GRP_FORK
+
+
+/**
+ * Fork completion callback used to release the thread db lock.
+ *
+ * @param   pvArg   NULL.
+ * @param   rc      The fork() result. Negative on failure.
+ * @param   enmCtx  The calling context.
+ */
+static void threadForkCompletion(void *pvArg, int rc, __LIBC_FORKCTX enmCtx)
+{
+    LIBCLOG_ENTER("pvArg=%p rc=%d enmCtx=%d - gfForkCleanupDone=%d\n", pvArg, rc, enmCtx, gfForkCleanupDone);
+
+    if (!gfForkCleanupDone)
+    {
+        LIBCLOG_MSG("Unlocking the thread DB.\n");
+        if (enmCtx == __LIBC_FORK_CTX_PARENT)
+            _fmutex_release(&gmtxThrdDB);
+        else
+            _fmutex_release_fork(&gmtxThrdDB);
+        gfForkCleanupDone = 1;
+    }
+    LIBCLOG_RETURN_VOID();
+}
+
+
+/**
+ * Parent fork callback for locking down the thread db while forking.
+ *
+ * @returns 0 on success.
+ * @returns -errno on failure.
+ * @param   pForkHandle     Pointer to fork handle.
+ * @param   enmOperation    Fork operation.
+ */
+static int threadForkParent1(__LIBC_PFORKHANDLE pForkHandle, __LIBC_FORKOP enmOperation)
+{
+    LIBCLOG_ENTER("pForkHandle=%p enmOperation=%d\n", (void *)pForkHandle, enmOperation);
+
+    if (enmOperation != __LIBC_FORK_OP_EXEC_PARENT)
+        LIBCLOG_RETURN_INT(0);
+
+    /*
+     * Lock the thread database before fork() and schedule an unlocking completion callback.
+     */
+    LIBCLOG_MSG("Locking the thead DB.\n");
+    if (_fmutex_request(&gmtxThrdDB, 0))
+        LIBCLOG_ERROR_RETURN_INT(-EDEADLK);
+
+    gfForkCleanupDone = 0;
+    int rc = pForkHandle->pfnCompletionCallback(pForkHandle, threadForkCompletion, NULL, __LIBC_FORK_CTX_BOTH);
+    if (rc >= 0)
+        LIBCLOG_RETURN_INT(rc);
+
+    _fmutex_release(&gmtxThrdDB);
+    LIBCLOG_ERROR_RETURN_INT(rc);
+}
+
+
+_FORK_PARENT1(0xffffff02, threadForkParent1)
+