/* Cleanup routines for GDB, the GNU debugger.
- Copyright (C) 1986, 1988-2012 Free Software Foundation, Inc.
+ Copyright (C) 1986-2013 Free Software Foundation, Inc.
This file is part of GDB.
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
+#include "gdb_assert.h"
+
+/* The cleanup list records things that have to be undone
+ if an error happens (descriptors to be closed, memory to be freed, etc.)
+ Each link in the chain records a function to call and an
+ argument to give it.
+
+ Use make_cleanup to add an element to the cleanup chain.
+ Use do_cleanups to do all cleanup actions back to a given
+ point in the chain. Use discard_cleanups to remove cleanups
+ from the chain back to a given point, not doing them.
+
+ If the argument is pointer to allocated memory, then you need
+ to additionally set the 'free_arg' member to a function that will
+ free that memory. This function will be called both when the cleanup
+ is executed and when it's discarded. */
+
+struct cleanup
+{
+ struct cleanup *next;
+ void (*function) (void *);
+ void (*free_arg) (void *);
+ void *arg;
+};
+
+/* Used to mark the end of a cleanup chain.
+ The value is chosen so that it:
+ - is non-NULL so that make_cleanup never returns NULL,
+ - causes a segv if dereferenced
+ [though this won't catch errors that a value of, say,
+ ((struct cleanup *) -1) will]
+ - displays as something useful when printed in gdb.
+ This is const for a bit of extra robustness.
+ It is initialized to coax gcc into putting it into .rodata.
+ All fields are initialized to survive -Wextra. */
+static const struct cleanup sentinel_cleanup = { 0, 0, 0, 0 };
+
+/* Handy macro to use when referring to sentinel_cleanup. */
+#define SENTINEL_CLEANUP ((struct cleanup *) &sentinel_cleanup)
/* Chain of cleanup actions established with make_cleanup,
to be executed if an error happens. */
+static struct cleanup *cleanup_chain = SENTINEL_CLEANUP;
-/* Cleaned up after a failed command. */
-static struct cleanup *cleanup_chain;
-
-/* Cleaned up when gdb exits. */
-static struct cleanup *final_cleanup_chain;
+/* Chain of cleanup actions established with make_final_cleanup,
+ to be executed when gdb exits. */
+static struct cleanup *final_cleanup_chain = SENTINEL_CLEANUP;
/* Main worker routine to create a cleanup.
PMY_CHAIN is a pointer to either cleanup_chain or final_cleanup_chain.
new->arg = arg;
*pmy_chain = new;
+ gdb_assert (old_chain != NULL);
return old_chain;
}
}
}
+/* Return a value that can be passed to do_cleanups, do_final_cleanups to
+ indicate perform all cleanups. */
+
+struct cleanup *
+all_cleanups (void)
+{
+ return SENTINEL_CLEANUP;
+}
+
/* Discard cleanups and do the actions they describe
until we get back to the point OLD_CHAIN in the cleanup_chain. */
{
struct cleanup *old_chain = *pmy_chain;
- *pmy_chain = 0;
+ *pmy_chain = SENTINEL_CLEANUP;
return old_chain;
}