1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
|
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package proc provides a platform-independent interface for
// tracing and controlling running processes. It supports
// multi-threaded processes and provides typical low-level debugging
// controls such as breakpoints, single stepping, and manipulating
// memory and registers.
package proc
// TODO(rsc): Have to import everything that proc_linux.go
// and proc_darwin.go do, because deps.bash only looks at
// this file.
import (
_ "container/vector"
_ "fmt"
_ "io"
"os"
_ "runtime"
"strconv"
_ "strings"
_ "sync"
_ "syscall"
)
type Word uint64
// A Cause explains why a thread is stopped.
type Cause interface {
String() string
}
// Regs is a set of named machine registers, including a program
// counter, link register, and stack pointer.
//
// TODO(austin) There's quite a proliferation of methods here. We
// could make a Reg interface with Get and Set and make this just PC,
// Link, SP, Names, and Reg. We could also put Index in Reg and that
// makes it easy to get the index of things like the PC (currently
// there's just no way to know that). This would also let us include
// other per-register information like how to print it.
type Regs interface {
// PC returns the value of the program counter.
PC() Word
// SetPC sets the program counter to val.
SetPC(val Word) os.Error
// Link returns the link register, if any.
Link() Word
// SetLink sets the link register to val.
SetLink(val Word) os.Error
// SP returns the value of the stack pointer.
SP() Word
// SetSP sets the stack pointer register to val.
SetSP(val Word) os.Error
// Names returns the names of all of the registers.
Names() []string
// Get returns the value of a register, where i corresponds to
// the index of the register's name in the array returned by
// Names.
Get(i int) Word
// Set sets the value of a register.
Set(i int, val Word) os.Error
}
// Thread is a thread in the process being traced.
type Thread interface {
// Step steps this thread by a single instruction. The thread
// must be stopped. If the thread is currently stopped on a
// breakpoint, this will step over the breakpoint.
//
// XXX What if it's stopped because of a signal?
Step() os.Error
// Stopped returns the reason that this thread is stopped. It
// is an error is the thread not stopped.
Stopped() (Cause, os.Error)
// Regs retrieves the current register values from this
// thread. The thread must be stopped.
Regs() (Regs, os.Error)
// Peek reads len(out) bytes from the address addr in this
// thread into out. The thread must be stopped. It returns
// the number of bytes successfully read. If an error occurs,
// such as attempting to read unmapped memory, this count
// could be short and an error will be returned. If this does
// encounter unmapped memory, it will read up to the byte
// preceding the unmapped area.
Peek(addr Word, out []byte) (int, os.Error)
// Poke writes b to the address addr in this thread. The
// thread must be stopped. It returns the number of bytes
// successfully written. If an error occurs, such as
// attempting to write to unmapped memory, this count could be
// short and an error will be returned. If this does
// encounter unmapped memory, it will write up to the byte
// preceding the unmapped area.
Poke(addr Word, b []byte) (int, os.Error)
}
// Process is a process being traced. It consists of a set of
// threads. A process can be running, stopped, or terminated. The
// process's state extends to all of its threads.
type Process interface {
// Threads returns an array of all threads in this process.
Threads() []Thread
// AddBreakpoint creates a new breakpoint at program counter
// pc. Breakpoints can only be created when the process is
// stopped. It is an error if a breakpoint already exists at
// pc.
AddBreakpoint(pc Word) os.Error
// RemoveBreakpoint removes the breakpoint at the program
// counter pc. It is an error if no breakpoint exists at pc.
RemoveBreakpoint(pc Word) os.Error
// Stop stops all running threads in this process before
// returning.
Stop() os.Error
// Continue resumes execution of all threads in this process.
// Any thread that is stopped on a breakpoint will be stepped
// over that breakpoint. Any thread that is stopped because
// of a signal (other than SIGSTOP or SIGTRAP) will receive
// the pending signal.
Continue() os.Error
// WaitStop waits until all threads in process p are stopped
// as a result of some thread hitting a breakpoint, receiving
// a signal, creating a new thread, or exiting.
WaitStop() os.Error
// Detach detaches from this process. All stopped threads
// will be resumed.
Detach() os.Error
}
// Stopped is a stop cause used for threads that are stopped either by
// user request (e.g., from the Stop method or after single stepping),
// or that are stopped because some other thread caused the program to
// stop.
type Stopped struct{}
func (c Stopped) String() string { return "stopped" }
// Breakpoint is a stop cause resulting from a thread reaching a set
// breakpoint.
type Breakpoint Word
// PC returns the program counter that the program is stopped at.
func (c Breakpoint) PC() Word { return Word(c) }
func (c Breakpoint) String() string {
return "breakpoint at 0x" + strconv.Uitob64(uint64(c.PC()), 16)
}
// Signal is a stop cause resulting from a thread receiving a signal.
// When the process is continued, the signal will be delivered.
type Signal string
// Signal returns the signal being delivered to the thread.
func (c Signal) Name() string { return string(c) }
func (c Signal) String() string { return c.Name() }
// ThreadCreate is a stop cause returned from an existing thread when
// it creates a new thread. The new thread exists in a primordial
// form at this point and will begin executing in earnest when the
// process is continued.
type ThreadCreate struct {
thread Thread
}
func (c *ThreadCreate) NewThread() Thread { return c.thread }
func (c *ThreadCreate) String() string { return "thread create" }
// ThreadExit is a stop cause resulting from a thread exiting. When
// this cause first arises, the thread will still be in the list of
// process threads and its registers and memory will still be
// accessible.
type ThreadExit struct {
exitStatus int
signal string
}
// Exited returns true if the thread exited normally.
func (c *ThreadExit) Exited() bool { return c.exitStatus != -1 }
// ExitStatus returns the exit status of the thread if it exited
// normally or -1 otherwise.
func (c *ThreadExit) ExitStatus() int { return c.exitStatus }
// Signaled returns true if the thread was terminated by a signal.
func (c *ThreadExit) Signaled() bool { return c.exitStatus == -1 }
// StopSignal returns the signal that terminated the thread, or "" if
// it was not terminated by a signal.
func (c *ThreadExit) StopSignal() string { return c.signal }
func (c *ThreadExit) String() string {
res := "thread exited "
switch {
case c.Exited():
res += "with status " + strconv.Itoa(c.ExitStatus())
case c.Signaled():
res += "from signal " + c.StopSignal()
default:
res += "from unknown cause"
}
return res
}
|
