CODEWITHSUNDEEP
gorefactoringruntime
Oleg
Oleg

Reputation: 3200

golang fetch all all filepathes from compiled file

I am trying to fetch all source files that where used during compilation. Function runtime.Caller() and panic with its stacktrace show this info.

I need something like this

func fetchUsedFiles() []string {
    ....
}
func main() {
    log.Println("Used Files",fetchUsedFiles())
}

UPD:

All what I need is read somehow "runtime.firstmoduledata" variable content. But it is not exported variable.

Upvotes: 1

Views: 477

Answers (1)

Oleg
Oleg

Reputation: 3200

Actually I have combined VonC answer and my runtime approcah.

All needed data stored at runtime.firstmoduledata - struct but they are not exported. To read data from there I read my executable file again (implemented only for ELF), find this symbol and do the other part like runtime.Caller() function. This method is not portable and can be broken by changes in runtime library but it works.

selfReflect function uses copies of private types from runtime lib

https://github.com/martende/restartable/blob/master/restartable.go#L208 

func selfReflect(filename string) ([]string,error) {
    f,err := elf.Open(filename)
    if err != nil {
        return nil,err
    }
    defer f.Close()
    syms,err := f.Symbols()
    if err != nil {
        return nil,err
    }
    var modSym elf.Symbol
    var modSymFound = false
    for _,v := range syms {
        if v.Name == "runtime.firstmoduledata" {
            modSym = v
            modSymFound = true
            break
        }
    }
    if ! modSymFound {
        return nil,errors.New("elfparse:nosym")
    }

    var datap = (*moduledata)(unsafe.Pointer(uintptr(modSym.Value)))

    files := make([]string,0)
    for i := range datap.filetab {
        bp := &datap.pclntable[datap.filetab[i]]
        file := C.GoString( (*C.char) (unsafe.Pointer(bp))  )
        if file != "<autogenerated>" && file != "@" {
            if _, err := os.Stat(file); err == nil {
                files = append(files ,file)
            }
        }
    }


    return files,nil
}

Upvotes: 1

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