proc

package
v0.7.0-alpha Latest Latest
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 Go to latest Published: Aug 14, 2015 License: MIT Imports: 24 Imported by: 0

Documentation

Overview

proc is a low-level package that provides methods to manipulate the process we are debugging.

proc implements all core functionality including: * creating / attaching to a process * process manipulation (step, next, continue, halt) * methods to explore the memory of the process

Index

Constants

View Source 
const (
	STATUS_SLEEPING   = 'S'
	STATUS_RUNNING    = 'R'
	STATUS_TRACE_STOP = 't'
	STATUS_ZOMBIE     = 'Z'
)

Process statuses

View Source 
const (
	ChanRecv = "chan receive"
	ChanSend = "chan send"
)

Variables

This section is empty.

Functions

func PtraceCont 

func PtraceCont(tid, sig int) error

func PtraceDetach 

func PtraceDetach(tid, sig int) error

func PtracePeekUser 

func PtracePeekUser(tid int, off uintptr) (uintptr, error)

func PtracePokeUser 

func PtracePokeUser(tid int, off, addr uintptr) error

func PtraceSingleStep 

func PtraceSingleStep(tid int) error

Types

type AMD64 

type AMD64 struct {
	// contains filtered or unexported fields
}

func AMD64Arch 

func AMD64Arch() *AMD64

func (*AMD64) BreakpointInstruction 

func (a *AMD64) BreakpointInstruction() []byte

func (*AMD64) BreakpointSize 

func (a *AMD64) BreakpointSize() int

func (*AMD64) GStructOffset 

func (a *AMD64) GStructOffset() uint64

func (*AMD64) HardwareBreakpointUsage 

func (a *AMD64) HardwareBreakpointUsage() []bool

func (*AMD64) PtrSize 

func (a *AMD64) PtrSize() int

func (*AMD64) SetGStructOffset 

func (a *AMD64) SetGStructOffset(ver GoVersion, isextld bool)

func (*AMD64) SetHardwareBreakpointUsage 

func (a *AMD64) SetHardwareBreakpointUsage(reg int, set bool)

type Arch 

type Arch interface {
	SetGStructOffset(ver GoVersion, iscgo bool)
	PtrSize() int
	BreakpointInstruction() []byte
	BreakpointSize() int
	GStructOffset() uint64
	HardwareBreakpointUsage() []bool
	SetHardwareBreakpointUsage(int, bool)
}

type Breakpoint 

type Breakpoint struct {
	// File & line information for printing.
	FunctionName string
	File         string
	Line         int

	Addr         uint64 // Address breakpoint is set for.
	OriginalData []byte // If software breakpoint, the data we replace with breakpoint instruction.
	ID           int    // Monotonically increasing ID.
	Temp         bool   // Whether this is a temp breakpoint (for next'ing).

	// Breakpoint information
	Tracepoint bool     // Tracepoint flag
	Stacktrace int      // Number of stack frames to retrieve
	Goroutine  bool     // Retrieve goroutine information
	Variables  []string // Variables to evaluate
	// contains filtered or unexported fields
}

Represents a single breakpoint. Stores information on the break point including the byte of data that originally was stored at that address.

func (*Breakpoint) Clear 

func (bp *Breakpoint) Clear(thread *Thread) (*Breakpoint, error)

Clear this breakpoint appropriately depending on whether it is a hardware or software breakpoint.

func (*Breakpoint) String 

func (bp *Breakpoint) String() string

type BreakpointExistsError 

type BreakpointExistsError struct {
	// contains filtered or unexported fields
}

Returned when trying to set a breakpoint at an address that already has a breakpoint set for it.

func (BreakpointExistsError) Error 

func (bpe BreakpointExistsError) Error() string

type G 

type G struct {
	Id         int    // Goroutine ID
	PC         uint64 // PC of goroutine when it was parked.
	SP         uint64 // SP of goroutine when it was parked.
	GoPC       uint64 // PC of 'go' statement that created this goroutine.
	WaitReason string // Reason for goroutine being parked.

	// Information on goroutine location.
	File string
	Line int
	Func *gosym.Func

	// PC of entry to top-most deferred function.
	DeferPC uint64
	// contains filtered or unexported fields
}

Represents a runtime G (goroutine) structure (at least the fields that Delve is interested in).

func (*G) ChanRecvBlocked 

func (g *G) ChanRecvBlocked() bool

Returns whether the goroutine is blocked on a channel read operation.

type GoVersion 

type GoVersion struct {
	Major int
	Minor int
	Rev   int
	Beta  int
	RC    int
}

func (*GoVersion) AfterOrEqual 

func (a *GoVersion) AfterOrEqual(b GoVersion) bool

func (*GoVersion) IsDevel 

func (v *GoVersion) IsDevel() bool

type GoroutineExitingError 

type GoroutineExitingError struct {
	// contains filtered or unexported fields
}

Go routine is exiting.

func (GoroutineExitingError) Error 

func (ge GoroutineExitingError) Error() string

type InvalidAddressError 

type InvalidAddressError struct {
	// contains filtered or unexported fields
}

InvalidAddressError represents the result of attempting to set a breakpoint at an invalid address.

func (InvalidAddressError) Error 

func (iae InvalidAddressError) Error() string

type Location 

type Location struct {
	PC   uint64
	File string
	Line int
	Fn   *gosym.Func
}

Represents the location of a thread. Holds information on the current instruction address, the source file:line, and the function.

type M 

type M struct {
	// contains filtered or unexported fields
}

Represents a runtime M (OS thread) structure.

type NoBreakpointError 

type NoBreakpointError struct {
	// contains filtered or unexported fields
}

Error thrown when trying to clear a breakpoint that does not exist.

func (NoBreakpointError) Error 

func (nbp NoBreakpointError) Error() string

type NoGError 

type NoGError struct {
	// contains filtered or unexported fields
}

NoGError returned when a G could not be found for a specific thread.

func (NoGError) Error 

func (ng NoGError) Error() string

type NullAddrError 

type NullAddrError struct{}

func (NullAddrError) Error 

func (n NullAddrError) Error() string

type OSProcessDetails 

type OSProcessDetails interface{}

Not actually needed for Linux.

type OSSpecificDetails 

type OSSpecificDetails struct {
	// contains filtered or unexported fields
}

Not actually used, but necessary to be defined.

type Process 

type Process struct {
	Pid     int         // Process Pid
	Process *os.Process // Pointer to process struct for the actual process we are debugging

	// Breakpoint table, hold information on software / hardware breakpoints.
	// Maps instruction address to Breakpoint struct.
	Breakpoints map[uint64]*Breakpoint

	// List of threads mapped as such: pid -> *Thread
	Threads map[int]*Thread

	// Active thread. This is the default thread used for setting breakpoints, evaluating variables, etc..
	CurrentThread *Thread
	// contains filtered or unexported fields
}

Process represents all of the information the debugger is holding onto regarding the process we are debugging.

func Attach 

func Attach(pid int) (*Process, error)

Attach to an existing process with the given PID.

func Launch 

func Launch(cmd []string) (*Process, error)

Create and begin debugging a new process. First entry in `cmd` is the program to run, and then rest are the arguments to be supplied to that process.

func New 

func New(pid int) *Process

func (*Process) ClearBreakpoint 

func (dbp *Process) ClearBreakpoint(addr uint64) (*Breakpoint, error)

Clears a breakpoint.

If it is a hardware assisted breakpoint, iterate through all threads and clear the debug register. Otherwise, restore original instruction.

func (*Process) Continue 

func (dbp *Process) Continue() error

Resume process.

func (*Process) CurrentBreakpoint 

func (dbp *Process) CurrentBreakpoint() *Breakpoint

Returns the PC of the current thread.

func (*Process) Detach 

func (dbp *Process) Detach(kill bool) (err error)

Detach from the process being debugged, optionally killing it.

func (*Process) DwarfReader 

func (dbp *Process) DwarfReader() *reader.Reader

Returns a reader for the dwarf data

func (*Process) EvalVariable 

func (dbp *Process) EvalVariable(name string) (*Variable, error)

Returns the value of the named symbol.

func (*Process) Exited 

func (dbp *Process) Exited() bool

Returns whether or not Delve thinks the debugged process has exited.

func (*Process) FindBreakpoint 

func (dbp *Process) FindBreakpoint(pc uint64) (*Breakpoint, bool)

Finds the breakpoint for the given pc.

func (*Process) FindBreakpointByID 

func (dbp *Process) FindBreakpointByID(id int) (*Breakpoint, bool)

Finds the breakpoint for the given ID.

func (*Process) FindFileLocation 

func (dbp *Process) FindFileLocation(fileName string, lineno int) (uint64, error)

func (*Process) FindFunctionLocation 

func (dbp *Process) FindFunctionLocation(funcName string, firstLine bool, lineOffset int) (uint64, error)

Finds address of a function's line If firstLine == true is passed FindFunctionLocation will attempt to find the first line of the function If lineOffset is passed FindFunctionLocation will return the address of that line Pass lineOffset == 0 and firstLine == false if you want the address for the function's entry point Note that setting breakpoints at that address will cause surprising behavior: https://github.com/derekparker/delve/issues/170

func (*Process) Funcs 

func (dbp *Process) Funcs() []gosym.Func

Returns list of functions present in the debugged program.

func (*Process) GoroutineLocation 

func (dbp *Process) GoroutineLocation(g *G) *Location

func (*Process) GoroutineStacktrace 

func (dbp *Process) GoroutineStacktrace(g *G, depth int) ([]Location, error)

Returns the stack trace for a goroutine. Note the locations in the array are return addresses not call addresses.

func (*Process) GoroutinesInfo 

func (dbp *Process) GoroutinesInfo() ([]*G, error)

Returns an array of G structures representing the information Delve cares about from the internal runtime G structure.

func (*Process) Halt 

func (dbp *Process) Halt() (err error)

Stop all threads.

func (*Process) Kill 

func (dbp *Process) Kill() (err error)

func (*Process) LoadInformation 

func (dbp *Process) LoadInformation(path string) error

Finds the executable and then uses it to parse the following information: * Dwarf .debug_frame section * Dwarf .debug_line section * Go symbol table.

func (*Process) Next 

func (dbp *Process) Next() error

Step over function calls.

func (*Process) PC 

func (dbp *Process) PC() (uint64, error)

Returns the PC of the current thread.

func (*Process) PCToLine 

func (dbp *Process) PCToLine(pc uint64) (string, int, *gosym.Func)

Converts an instruction address to a file/line/function.

func (*Process) Registers 

func (dbp *Process) Registers() (Registers, error)

Obtains register values from what Delve considers to be the current thread of the traced process.

func (*Process) RequestManualStop 

func (dbp *Process) RequestManualStop() error

Sends out a request that the debugged process halt execution. Sends SIGSTOP to all threads.

func (*Process) Running 

func (dbp *Process) Running() bool

Returns whether or not Delve thinks the debugged process is currently executing.

func (*Process) SetBreakpoint 

func (dbp *Process) SetBreakpoint(addr uint64) (*Breakpoint, error)

Sets a breakpoint at addr, and stores it in the process wide break point table. Setting a break point must be thread specific due to ptrace actions needing the thread to be in a signal-delivery-stop.

Depending on hardware support, Delve will choose to either set a hardware or software breakpoint. Essentially, if the hardware supports it, and there are free debug registers, Delve will set a hardware breakpoint. Otherwise we fall back to software breakpoints, which are a bit more work for us.

func (*Process) SetTempBreakpoint 

func (dbp *Process) SetTempBreakpoint(addr uint64) (*Breakpoint, error)

Sets a temp breakpoint, for the 'next' command.

func (*Process) Sources 

func (dbp *Process) Sources() map[string]*gosym.Obj

Returns list of source files that comprise the debugged binary.

func (*Process) Status 

func (dbp *Process) Status() *sys.WaitStatus

Returns the status of the current main thread context.

func (*Process) Step 

func (dbp *Process) Step() (err error)

Single step, will execute a single instruction.

func (*Process) SwitchThread 

func (dbp *Process) SwitchThread(tid int) error

Change from current thread to the thread specified by `tid`.

type ProcessExitedError 

type ProcessExitedError struct {
	Pid    int
	Status int
}

ProcessExitedError indicates that the process has exited and contains both process id and exit status.

func (ProcessExitedError) Error 

func (pe ProcessExitedError) Error() string

type Registers 

type Registers interface {
	PC() uint64
	SP() uint64
	CX() uint64
	TLS() uint64
	SetPC(*Thread, uint64) error
	String() string
}

An interface for a generic register type. The interface encapsulates the generic values / actions we need independant of arch. The concrete register types will be different depending on OS/Arch.

type Regs 

type Regs struct {
	// contains filtered or unexported fields
}

func (*Regs) CX 

func (r *Regs) CX() uint64

func (*Regs) PC 

func (r *Regs) PC() uint64

func (*Regs) SP 

func (r *Regs) SP() uint64

func (*Regs) SetPC 

func (r *Regs) SetPC(thread *Thread, pc uint64) (err error)

func (*Regs) String 

func (r *Regs) String() string

func (*Regs) TLS 

func (r *Regs) TLS() uint64

type Thread 

type Thread struct {
	Id                int             // Thread ID or mach port
	Status            *sys.WaitStatus // Status returned from last wait call
	CurrentBreakpoint *Breakpoint     // Breakpoint thread is currently stopped at
	// contains filtered or unexported fields
}

Thread represents a single thread in the traced process Id represents the thread id or port, Process holds a reference to the Process struct that contains info on the process as a whole, and Status represents the last result of a `wait` call on this thread.

func (*Thread) Continue 

func (thread *Thread) Continue() error

Continue the execution of this thread.

If we are currently at a breakpoint, we'll clear it first and then resume execution. Thread will continue until it hits a breakpoint or is signaled.

func (*Thread) EvalPackageVariable 

func (thread *Thread) EvalPackageVariable(name string) (*Variable, error)

func (*Thread) EvalVariable 

func (thread *Thread) EvalVariable(name string) (*Variable, error)

Returns the value of the named variable.

func (*Thread) FunctionArguments 

func (thread *Thread) FunctionArguments() ([]*Variable, error)

FunctionArguments returns the name, value, and type of all current function arguments.

func (*Thread) GetG 

func (thread *Thread) GetG() (g *G, err error)

Returns information on the G (goroutine) that is executing on this thread.

The G structure for a thread is stored in thread local memory. Execute instructions that move the *G structure into a CPU register, and then grab the new registers and parse the G structure.

We cannot simply use the allg linked list in order to find the M that represents the given OS thread and follow its G pointer because on Darwin mach ports are not universal, so our port for this thread would not map to the `id` attribute of the M structure. Also, when linked against libc, Go prefers the libc version of clone as opposed to the runtime version. This has the consequence of not setting M.id for any thread, regardless of OS.

In order to get around all this craziness, we read the address of the G structure for the current thread from the thread local storage area.

func (*Thread) Halt 

func (t *Thread) Halt() error

func (*Thread) LocalVariables 

func (thread *Thread) LocalVariables() ([]*Variable, error)

LocalVariables returns all local variables from the current function scope.

func (*Thread) Location 

func (thread *Thread) Location() (*Location, error)

Returns the threads location, including the file:line of the corresponding source code, the function we're in and the current instruction address.

func (*Thread) PC 

func (thread *Thread) PC() (uint64, error)

Returns the current PC for this thread.

func (*Thread) PackageVariables 

func (thread *Thread) PackageVariables() ([]*Variable, error)

PackageVariables returns the name, value, and type of all package variables in the application.

func (*Thread) Registers 

func (thread *Thread) Registers() (Registers, error)

Obtains register values from the debugged process.

func (*Thread) ReturnAddress 

func (thread *Thread) ReturnAddress() (uint64, error)

Takes an offset from RSP and returns the address of the instruction the current function is going to return to.

func (*Thread) SetNextBreakpoints 

func (thread *Thread) SetNextBreakpoints() (err error)

Set breakpoints for potential next lines.

There are two modes of operation for this method. First, if we are executing Go code, we can use the stdlib AST information to determine which lines we could potentially end up at. Parsing the source file into an AST and traversing it lets us gain insight into whether we're at a branch, and where that branch could end up at, etc...

However, if we are executing C code, we use the DWARF debug_line information and essentially set a breakpoint at every single line within the current function, and another at the functions return address, in case we're at the end.

func (*Thread) SetPC 

func (thread *Thread) SetPC(pc uint64) error

Sets the PC for this thread.

func (*Thread) Stacktrace 

func (thread *Thread) Stacktrace(depth int) ([]Location, error)

Returns the stack trace for thread. Note the locations in the array are return addresses not call addresses.

func (*Thread) Step 

func (thread *Thread) Step() (err error)

Step a single instruction.

Executes exactly one instruction and then returns. If the thread is at a breakpoint, we first clear it, execute the instruction, and then replace the breakpoint. Otherwise we simply execute the next instruction.

type Variable 

type Variable struct {
	Name  string
	Value string
	Type  string
}

Represents an evaluated variable.

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