liamzdenek / go-pthreads Goto Github PK

I could be mistaken but I feel that func Create (), can return address of a local variable which gets destroyed after the end func Create(). At line 55 in func Create (), pidptr is defined to point to address of function local variable "pid" which stores the pthread_t returned by pthread_create() library call. pthread_create() requires the address of a variable (as is normal for all kernel calls) to return the pthread_t value.
Now, since we return the address of local variable "pid" after converting it to a unsafe.Pointer, the garbage collector of 'go' will not add an extra reference to the local variable "pid" and when we return the said value, it may get overwritten. Any subsequent attempt to kill the thread represented by 'Thread' may now work or may not depending on whether the local variable value was overwritten or otherwise.
It's probably best to ask the user to supply a type 'Thread' as an argument to func Create() and return the pid in the passed caller variable, than allocating one on stack of func Create(). Makes sense ?

This might also perhaps explain the error seen by kryptodev.

I am a bit concerned about the things you claim this library does. To be absolutely clear, there is no mechanism on any modern operating system to "kill" a thread. In fact, your library using pthread_kill to send itself a SIGSEGV (which is a segmentation fault, by the way) will probably kill something, but almost certainly not the thing you intend.

By the way, the only difference between pthread_kill and kill is that you can use the pthread_t thread id to specify which task gets the signal. By default, the signal still applies to the entire process. Doing what you're doing in a C program will promptly exit the entire process. In Go, it probably leads to undefined behavior.

This library is broken by design, and I promise you that it's not doing what you think it's doing.

Hello,

I hope I am not simply making a mistake but I have noticed that when I create a pthread inside a new goroutine(not the main), and I try to call thread.kill(), it does not always work. Sometimes I does, other times it just gets stuck.

It would be very kind of you to investigate this in your free time.

Thank you

(This is not bug report or enhancement :)

I tested for long running routine and found there is no way to check the thread is alive or not. Of course Thread.Running is available but it seems to be incomplete. This is simple method to check whether long running routine is finished or not, using channel.

_ch := make(chan bool)

thread := pthread.Create(func() {
    ... long running routine ...

    _ch <- true
})

<- _ch

Thanks.