Debugging 如何使用BPF（BCC）跟踪go函数

我的客户有一些密码。这里看起来似乎只有mypackage是相关的：

package mypackage

import (
...

func (o *Client) CreateUser(ctx context.Context, user *User, ...) (User, error) {
    ...
    if err != nil ...
      return nil, err
    ...
    return &user, nil
}

我运行go build-o build/myclient cmd/myclient/main.go来获取二进制文件

λ bob [~]  → objdump -t ~/go/src/github.com/Corp/myclient/build/myclient | grep CreateUser
....
000000000087d490 l     F .text  0000000000000e55              github.com/Corp/myclient.(*Client).CreateUser

现在这个二进制文件被其他一些go程序使用并被加载

不知怎的，是这样的：

bob      745322  0.1  0.1 195556  33172 pts/1    Sl+  20:18   0:07 some-prog
bob      750774  0.0  0.0 1229316 14188 pts/1    Sl+  20:22   0:00 /home/bob/go/src/github.com/Corp/myclient/build/myclient

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:mypackage.*'  
could not determine address of symbol b'mypackage.*'

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.CreateUser'                          
could not determine address of symbol b'github.com/Corp/myclient.CreateUser'

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.(*Client).CreateUser'
error in probe '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.(*Client).CreateUser': expected format string in "s

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:*.CreateUser'                                                               
could not determine address of symbol b'*.CreateUser'

现在我尝试使用BCC工具进行跟踪/调试。这是因为在生产中发生了一些奇怪的错误，查看上面函数的参数和返回值非常重要。我的灵感来自：

在使用funccount时，通过调用some prog调用函数后，我在这里看到了这一点

λ bob [~]  → sudo funccount '/home/bob/go/src/github.com/Corp/myclient/build/myclient:*.CreateUser'
Tracing 5 functions for "b'/home/bob/go/src/github.com/Corp/myclient/build/myclient:*.CreateUser'"... Hit Ctrl-C to end.
^C
FUNC                                                    COUNT
...
b'github.com/Corp/myclient.(*Client).CreateUser'        1
Detaching...

但当我尝试使用trace或gotrace时，它看起来是这样的：

bob      745322  0.1  0.1 195556  33172 pts/1    Sl+  20:18   0:07 some-prog
bob      750774  0.0  0.0 1229316 14188 pts/1    Sl+  20:22   0:00 /home/bob/go/src/github.com/Corp/myclient/build/myclient

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:mypackage.*'  
could not determine address of symbol b'mypackage.*'

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.CreateUser'                          
could not determine address of symbol b'github.com/Corp/myclient.CreateUser'

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.(*Client).CreateUser'
error in probe '/home/bob/go/src/github.com/Corp/myclient/build/myclient:github.com/Corp/myclient.(*Client).CreateUser': expected format string in "s

λ bob [~]  → trace '/home/bob/go/src/github.com/Corp/myclient/build/myclient:*.CreateUser'                                                               
could not determine address of symbol b'*.CreateUser'

---

是否有可能使用BCC工具或eBPF/bpftrace跟踪此类go函数，尤其是检查结构参数和返回值？无需添加任何代码，trace是一个python脚本，您可以在vim中打开它，然后搜索名为_parse_probe的函数。在此函数中，第96行：

(spec, sig, rest) = re.match(r'([^ \t\(]+)(\([^\(]*\))?(.*)', text).groups()                                    

带有字符的golang函数符号分为3部分，而普通函数将匹配第一个正则子字符串。您可以修改正则表达式并删除零件，然后跟踪将起作用。祝你好运