mirror of
https://github.com/dutchcoders/transfer.sh.git
synced 2020-11-18 19:53:40 -08:00
125 lines
2.9 KiB
Go
125 lines
2.9 KiB
Go
// Copyright 2014 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package binutils
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import (
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"bufio"
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"bytes"
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"io"
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"os/exec"
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"strconv"
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"strings"
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"github.com/google/pprof/internal/plugin"
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)
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const (
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defaultNM = "nm"
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)
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// addr2LinerNM is a connection to an nm command for obtaining address
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// information from a binary.
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type addr2LinerNM struct {
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m []symbolInfo // Sorted list of addresses from binary.
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}
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type symbolInfo struct {
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address uint64
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name string
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}
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// newAddr2LinerNM starts the given nm command reporting information about the
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// given executable file. If file is a shared library, base should be
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// the address at which it was mapped in the program under
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// consideration.
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func newAddr2LinerNM(cmd, file string, base uint64) (*addr2LinerNM, error) {
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if cmd == "" {
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cmd = defaultNM
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}
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var b bytes.Buffer
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c := exec.Command(cmd, "-n", file)
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c.Stdout = &b
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if err := c.Run(); err != nil {
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return nil, err
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}
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return parseAddr2LinerNM(base, &b)
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}
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func parseAddr2LinerNM(base uint64, nm io.Reader) (*addr2LinerNM, error) {
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a := &addr2LinerNM{
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m: []symbolInfo{},
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}
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// Parse nm output and populate symbol map.
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// Skip lines we fail to parse.
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buf := bufio.NewReader(nm)
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for {
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line, err := buf.ReadString('\n')
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if line == "" && err != nil {
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if err == io.EOF {
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break
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}
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return nil, err
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}
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line = strings.TrimSpace(line)
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fields := strings.SplitN(line, " ", 3)
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if len(fields) != 3 {
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continue
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}
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address, err := strconv.ParseUint(fields[0], 16, 64)
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if err != nil {
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continue
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}
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a.m = append(a.m, symbolInfo{
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address: address + base,
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name: fields[2],
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})
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}
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return a, nil
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}
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// addrInfo returns the stack frame information for a specific program
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// address. It returns nil if the address could not be identified.
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func (a *addr2LinerNM) addrInfo(addr uint64) ([]plugin.Frame, error) {
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if len(a.m) == 0 || addr < a.m[0].address || addr > a.m[len(a.m)-1].address {
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return nil, nil
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}
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// Binary search. Search until low, high are separated by 1.
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low, high := 0, len(a.m)
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for low+1 < high {
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mid := (low + high) / 2
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v := a.m[mid].address
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if addr == v {
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low = mid
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break
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} else if addr > v {
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low = mid
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} else {
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high = mid
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}
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}
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// Address is between a.m[low] and a.m[high].
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// Pick low, as it represents [low, high).
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f := []plugin.Frame{
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{
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Func: a.m[low].name,
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},
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}
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return f, nil
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}
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