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digitalmars.D.learn - Issue with socket recieve

reply Tim <tim.oliver tutanota.com> writes:
Hi all,

I'm having a really terrible bug that seemed to come from nowhere 
and is really hard to narrow down. I have a threaded message 
service that works via local TcpSocket. Every time I run it, 
either an error saying:

Unable to open 'recv.c': Unable to read file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c' 
(Error: Unable to resolve non-existing file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c').


when socket.receive() is called. Sometimes I get the same thing 
but for socket.accept() instead (different file). This seems to 
generate a core.exception.InvalidMemoryOperationError that I 
can't catch.

Yesterday, this came up after a couple of minutes of the program 
running, now it happens straight away. I haven't touched this 
class in a week or so and can't think of why all of a sudden it 
has come up with this issue. Code dump below

---------------------------------------------



module message_service;

import std.stdio;
import std.socket;
import core.thread;


/**
Threaded socket manager to serve inter-service communication

Calls delegates when the appropriate command is received
*/
class MessageService : Thread{
    /// The socket over which communication is possible
    private Socket server;
    /// The connection to the client that sends commands
    private Socket client;
    /// Associative array of command strings and relative 
 functions to call
    private void delegate()[string] commands;
    /// Global buffer. Holds the command being recieved
    private char[1024] buffer = 0;
 

    ///
    this(ushort port, void delegate()[string] _commands){
        commands = _commands;
        server = new TcpSocket();
        server.setOption(SocketOptionLevel.SOCKET, 
 SocketOption.REUSEADDR, true);
        server.bind(new InternetAddress(port));
        writefln("Message service started on port %d", port);
        super(&mainLoop);
        start();
    }


    /// Loops over polling the client socket for commands
    void mainLoop(){
        while(true){
            pollMessages();
        }
    }


    /**
    Polls the client socket for characters to build up the 
 message buffer
 
    When a string command is found, it calls the appropriate 
 function
    */
    void pollMessages(){
        server.listen(1);
        if(client is null) client = server.accept();

        // Add to the message buffer
        auto buffLength = client.receive(buffer);

        if(buffLength){
            auto message = cast(string) buffer[0 .. buffLength];
 
            foreach(cmd; commands.byKey){
                if(cmd == message){
                    // Reset the message buffer
                    buffer = 0;
                    commands[cmd]();
                    return;
                }
            }
        }
    }
}
Jan 20 2021
next sibling parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Wednesday, 20 January 2021 at 21:31:54 UTC, Tim wrote:

Unable to open 'recv.c': Unable to read file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c' 
(Error: Unable to resolve non-existing file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c').


 [snip]
 generate a core.exception.InvalidMemoryOperationError that I 
 can't catch.



None of this makes much sense given the code you provided. 
InvalidMemoryOperationError (the scariest thing in D btw, such a 
pain to debug) is usually caused by a class destructor somewhere, 
and none of those should be trying to resolve those files.

Do you have any destructors defined?
Jan 20 2021
next sibling parent reply Tim <tim.oliver tutanota.com> writes:
On Thursday, 21 January 2021 at 03:21:41 UTC, Adam D. Ruppe wrote:

 On Wednesday, 20 January 2021 at 21:31:54 UTC, Tim wrote:

Unable to open 'recv.c': Unable to read file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c' (Error: Unable
to resolve non-existing file
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c').


 [snip]
 generate a core.exception.InvalidMemoryOperationError that I 
 can't catch.



 None of this makes much sense given the code you provided. 
 InvalidMemoryOperationError (the scariest thing in D btw, such 
 a pain to debug) is usually caused by a class destructor 
 somewhere, and none of those should be trying to resolve those 
 files.

 Do you have any destructors defined?


No, I don't. It should be all garbage collected right?

Hahahaha, about 50% of my troubles are 
InvalidMemoryOperationError! It's so frustrating. This whole 
project has been a nightmare
Jan 20 2021
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Thursday, 21 January 2021 at 03:24:13 UTC, Tim wrote:

 No, I don't. It should be all garbage collected right?


Yeah, but that's where the problem comes.

Note that by destructor, I mean *any* function in your code 
called `~this() {}`. If there are any and they call a memory 
allocation function, that's how you get the 
InvalidMemoryOperationError.

I'd have to look up if there's any other causes of that...
Jan 20 2021
parent Tim <tim.oliver tutanota.com> writes:
On Thursday, 21 January 2021 at 03:35:05 UTC, Adam D. Ruppe wrote:

 On Thursday, 21 January 2021 at 03:24:13 UTC, Tim wrote:

 No, I don't. It should be all garbage collected right?


 Yeah, but that's where the problem comes.

 Note that by destructor, I mean *any* function in your code 
 called `~this() {}`. If there are any and they call a memory 
 allocation function, that's how you get the 
 InvalidMemoryOperationError.

 I'd have to look up if there's any other causes of that...


I am aware of this, there is absolutely no ~this in *my* code
Jan 20 2021
prev sibling parent reply Tim <tim.oliver tutanota.com> writes:
On Thursday, 21 January 2021 at 03:21:41 UTC, Adam D. Ruppe wrote:

 On Wednesday, 20 January 2021 at 21:31:54 UTC, Tim wrote:

Unable to open 'recv.c': Unable to read file 
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c' (Error: Unable
to resolve non-existing file
'/build/glibc-ZN95T4/glibc-2.31/sysdeps/unix/sysv/linux/recv.c').


 [snip]
 generate a core.exception.InvalidMemoryOperationError that I 
 can't catch.



 None of this makes much sense given the code you provided. 
 InvalidMemoryOperationError (the scariest thing in D btw, such 
 a pain to debug) is usually caused by a class destructor 
 somewhere, and none of those should be trying to resolve those 
 files.

 Do you have any destructors defined?


You seem like a rather switched-on fellow. Would you be able to 
send me an email at some point at tim.oliver tutanota.com. I have 
a proposition for you.
Jan 20 2021
parent Imperatorn <johan_forsberg_86 hotmail.com> writes:
On Thursday, 21 January 2021 at 03:30:50 UTC, Tim wrote:

 On Thursday, 21 January 2021 at 03:21:41 UTC, Adam D. Ruppe 
 wrote:

 On Wednesday, 20 January 2021 at 21:31:54 UTC, Tim wrote:

[...]


 [snip]
 generate a core.exception.InvalidMemoryOperationError that I 
 can't catch.



 None of this makes much sense given the code you provided. 
 InvalidMemoryOperationError (the scariest thing in D btw, such 
 a pain to debug) is usually caused by a class destructor 
 somewhere, and none of those should be trying to resolve those 
 files.

 Do you have any destructors defined?


 You seem like a rather switched-on fellow. Would you be able to 
 send me an email at some point at tim.oliver tutanota.com. I 
 have a proposition for you.


On Discord fyi
Jan 22 2021
prev sibling parent Mike Parker <aldacron gmail.com> writes:
On Wednesday, 20 January 2021 at 21:31:54 UTC, Tim wrote:

 Hi all,

 I'm having a really terrible bug that seemed to come from 
 nowhere and is really hard to narrow down.


You may be hitting this issue:

https://issues.dlang.org/show_bug.cgi?id=7349

FWIW, popped onto the radar in the most recent Foundation meeting.
Jan 22 2021