*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/storage/ipc/ipc.c,v 1.102 2009/01/01 17:23:47 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/storage/ipc/ipc.c,v 1.103 2009/05/05 20:06:07 tgl Exp $
*
*-------------------------------------------------------------------------
*/
*/
bool proc_exit_inprogress = false;
+/*
+ * This flag tracks whether we've called atexit(2) in the current process
+ * (or in the parent postmaster).
+ */
+static bool atexit_callback_setup = false;
+
+/* local functions */
+static void proc_exit_prepare(int code);
+
/* ----------------------------------------------------------------
* exit() handling stuff
*
* this function calls all the callbacks registered
* for it (to free resources) and then calls exit.
+ *
* This should be the only function to call exit().
* -cim 2/6/90
+ *
+ * Unfortunately, we can't really guarantee that add-on code
+ * obeys the rule of not calling exit() directly. So, while
+ * this is the preferred way out of the system, we also register
+ * an atexit callback that will make sure cleanup happens.
* ----------------------------------------------------------------
*/
void
proc_exit(int code)
{
- /*
- * Once we set this flag, we are committed to exit. Any ereport() will
- * NOT send control back to the main loop, but right back here.
- */
- proc_exit_inprogress = true;
-
- /*
- * Forget any pending cancel or die requests; we're doing our best to
- * close up shop already. Note that the signal handlers will not set
- * these flags again, now that proc_exit_inprogress is set.
- */
- InterruptPending = false;
- ProcDiePending = false;
- QueryCancelPending = false;
- /* And let's just make *sure* we're not interrupted ... */
- ImmediateInterruptOK = false;
- InterruptHoldoffCount = 1;
- CritSectionCount = 0;
-
- elog(DEBUG3, "proc_exit(%d)", code);
-
- /* do our shared memory exits first */
- shmem_exit(code);
-
- /*
- * call all the callbacks registered before calling exit().
- *
- * Note that since we decrement on_proc_exit_index each time, if a
- * callback calls ereport(ERROR) or ereport(FATAL) then it won't be
- * invoked again when control comes back here (nor will the
- * previously-completed callbacks). So, an infinite loop should not be
- * possible.
- */
- while (--on_proc_exit_index >= 0)
- (*on_proc_exit_list[on_proc_exit_index].function) (code,
- on_proc_exit_list[on_proc_exit_index].arg);
-
- elog(DEBUG3, "exit(%d)", code);
+ /* Clean up everything that must be cleaned up */
+ proc_exit_prepare(code);
#ifdef PROFILE_PID_DIR
{
*
* Note that we do this here instead of in an on_proc_exit() callback
* because we want to ensure that this code executes last - we don't
- * want to interfere with any other on_proc_exit() callback.
+ * want to interfere with any other on_proc_exit() callback. For
+ * the same reason, we do not include it in proc_exit_prepare ...
+ * so if you are exiting in the "wrong way" you won't drop your profile
+ * in a nice place.
*/
char gprofDirName[32];
}
#endif
+ elog(DEBUG3, "exit(%d)", code);
+
exit(code);
}
+/*
+ * Code shared between proc_exit and the atexit handler. Note that in
+ * normal exit through proc_exit, this will actually be called twice ...
+ * but the second call will have nothing to do.
+ */
+static void
+proc_exit_prepare(int code)
+{
+ /*
+ * Once we set this flag, we are committed to exit. Any ereport() will
+ * NOT send control back to the main loop, but right back here.
+ */
+ proc_exit_inprogress = true;
+
+ /*
+ * Forget any pending cancel or die requests; we're doing our best to
+ * close up shop already. Note that the signal handlers will not set
+ * these flags again, now that proc_exit_inprogress is set.
+ */
+ InterruptPending = false;
+ ProcDiePending = false;
+ QueryCancelPending = false;
+ /* And let's just make *sure* we're not interrupted ... */
+ ImmediateInterruptOK = false;
+ InterruptHoldoffCount = 1;
+ CritSectionCount = 0;
+
+ /* do our shared memory exits first */
+ shmem_exit(code);
+
+ elog(DEBUG3, "proc_exit(%d)", code);
+
+ /*
+ * call all the registered callbacks.
+ *
+ * Note that since we decrement on_proc_exit_index each time, if a
+ * callback calls ereport(ERROR) or ereport(FATAL) then it won't be
+ * invoked again when control comes back here (nor will the
+ * previously-completed callbacks). So, an infinite loop should not be
+ * possible.
+ */
+ while (--on_proc_exit_index >= 0)
+ (*on_proc_exit_list[on_proc_exit_index].function) (code,
+ on_proc_exit_list[on_proc_exit_index].arg);
+
+ on_proc_exit_index = 0;
+}
+
/* ------------------
* Run all of the on_shmem_exit routines --- but don't actually exit.
* This is used by the postmaster to re-initialize shared memory and
on_shmem_exit_index = 0;
}
+/* ----------------------------------------------------------------
+ * atexit_callback
+ *
+ * Backstop to ensure that direct calls of exit() don't mess us up.
+ *
+ * Somebody who was being really uncooperative could call _exit(),
+ * but for that case we have a "dead man switch" that will make the
+ * postmaster treat it as a crash --- see pmsignal.c.
+ * ----------------------------------------------------------------
+ */
+#ifdef HAVE_ATEXIT
+
+static void
+atexit_callback(void)
+{
+ /* Clean up everything that must be cleaned up */
+ /* ... too bad we don't know the real exit code ... */
+ proc_exit_prepare(-1);
+}
+
+#else /* assume we have on_exit instead */
+
+static void
+atexit_callback(int exitstatus, void *arg)
+{
+ /* Clean up everything that must be cleaned up */
+ proc_exit_prepare(exitstatus);
+}
+
+#endif /* HAVE_ATEXIT */
+
/* ----------------------------------------------------------------
* on_proc_exit
*
on_proc_exit_list[on_proc_exit_index].arg = arg;
++on_proc_exit_index;
+
+ if (!atexit_callback_setup)
+ {
+#ifdef HAVE_ATEXIT
+ atexit(atexit_callback);
+#else
+ on_exit(atexit_callback, NULL);
+#endif
+ atexit_callback_setup = true;
+ }
}
/* ----------------------------------------------------------------
on_shmem_exit_list[on_shmem_exit_index].arg = arg;
++on_shmem_exit_index;
+
+ if (!atexit_callback_setup)
+ {
+#ifdef HAVE_ATEXIT
+ atexit(atexit_callback);
+#else
+ on_exit(atexit_callback, NULL);
+#endif
+ atexit_callback_setup = true;
+ }
}
/* ----------------------------------------------------------------
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