ProcessControl.java revision 9883:903a2e023ffb 
1/*
2 * Copyright (c) 2001, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25package sun.jvm.hotspot.debugger.cdbg;
26
27import sun.jvm.hotspot.debugger.*;
28
29/** <P> A highly experimental interface for process control and debug
30    events. May not be sufficiently portable; for this reason it has
31    been factored out from the CDebugger interface and support for it
32    is optional. </P>
33
34    <P> The ProcessControl interface defines a process control and
35    event model for debugging. When a process is attached to by the
36    base Debugger, all threads in the target process are suspended.
37    The ProcessControl interface allows resumption and re-suspension
38    of the threads in the target process, setting of breakpoints, and
39    reception of debugging events (breakpoint hit, signal received,
40    etc.). </P>
41
42    <P> Debugging events are generated one at a time by the target
43    process. They must be queued up by the underlying debugging
44    mechanism so that an attempt to send a second debugging event
45    blocks until the first has been serviced with a call to
46    debugEventResume. </P> */
47
48public interface ProcessControl {
49  /** Suspends all threads in the target process. A process is already
50      suspended when attached to by {@link
51      sun.jvm.hotspot.debugger.Debugger.attach(int)}. The application
52      should check for the presence of a debug event via
53      debugEventPoll() upon re-suspending the target process (if one
54      is not yet known to be present.)
55
56      @throw DebuggerException if the process is already suspended or
57      if the suspension failed for some other reason. */
58  public void suspend() throws DebuggerException;
59
60  /** Resumes all threads in the target process.
61
62      @throw DebuggerException if the process is not suspended or if
63      the resumption failed for some other reason. */
64  public void resume() throws DebuggerException;
65
66  /** Indicates whether the target process is suspended. */
67  public boolean isSuspended() throws DebuggerException;
68
69  /** Sets a breakpoint at the given address. The target process must
70      be suspended in order to set a breakpoint.
71
72      @throw DebuggerException if the breakpoint could not be set for
73      some reason, including that a breakpoint is already set at that
74      address or that the underlying debugging mechanism does not
75      support that many breakpoints. */
76  public void setBreakpoint(Address addr)
77    throws UnmappedAddressException, DebuggerException;
78
79  /** Clears a breakpoint at the given address. The target process
80      must be suspended in order to clear a breakpoint.
81
82      @throw DebuggerException if the breakpoint could not be cleared
83      for some reason, including that there was no breakpoint at that
84      address. */
85  public void clearBreakpoint(Address addr) throws DebuggerException;
86
87  /** Indicates whether a breakpoint is set at the given address. */
88  public boolean isBreakpointSet(Address addr) throws DebuggerException;
89
90  /** Polls for the presence of a debug event. Does not wait for one
91      to be generated; returns null if none was pending. The target
92      process does not need to be suspended. Returns the same
93      DebugEvent object until the debug event is handled via
94      debugEventContinue. Typically the application will suspend the
95      target process upon reception of a debug event but before
96      handling it via a call to debugEventContinue. This ensures that
97      the state of the thread which generated the debug event is
98      precisely what it was when the event was generated.
99
100      @return The pending debug event, or null if none pending. */
101  public DebugEvent debugEventPoll() throws DebuggerException;
102
103  /** Informs the target process to resume past this debug event. The
104      target process does not need to be suspended. Breakpoint debug
105      events must be handled transparently by the implementation to
106      re-execute the instruction and replace the breakpoint. (Ideally
107      they should be replaced in such a way that there is no race
108      condition between the re-execution and the re-insertion of the
109      breakpoint.) All other kinds of exceptions or signals are passed
110      on to the target process.
111
112      @throw DebuggerException if no debug event is pending. */
113  public void debugEventContinue()
114    throws DebuggerException;
115}
116