unix domain socket filepaths should be translated

[hhm0]

Currently, paths for Unix domain sockets are not being translated to target paths..

This can prevent programs which depend on them to fail (which can cause filesystem errors which may not make sense to a user), or to need customized settings (e.g. tmux -S ./tmp/tmux, without / at beginning of filepath).

I think the fix would be to detect the bind system call when sockaddr.sun_family equals AF_UNIX, and then translate sockaddr.sun_path to a target filepath when it is found.

This came up while trying to use tmux on tal-dew on an Android phone. tmux tries to make a unix domain socket in /tmp, a directory Android does not have (in version 2.3 which I tested on).

[cedric-vincent]

Nice catch! I'm looking at this problem.

[hhm0]

Thank you! :-)

On Thu, Feb 21, 2013 at 3:28 AM, Cédric VINCENT notifications@github.comwrote:

Nice catch! I'm looking at this problem.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/8#issuecomment-13878088.

[cedric-vincent]

Commit 2001f0d should fix this problem.

[cedric-vincent]

Oops, the related test-case fails on Ubuntu: https://travis-ci.org/cedric-vincent/PRoot/builds/5039014/#L117

[cedric-vincent]

It works on Ubuntu locally. Maybe the problem is due to the Travis sandboxing: https://travis-ci.org/cedric-vincent/PRoot/builds/5039412/#L2729

[cedric-vincent]

I forgot to handle socketcall(2) too.

[cedric-vincent]

commit da92b78 fixes a critical bug in the previous implementation. I checked it now works with tmux on x86_64. Support for socketcall(2) and sendto(2) is still missing.

[cedric-vincent]

Hello @hhm0

Do you confirm the release v2.4.1 works as expected in this regard?

Regards,
Cedric.

[hhm0]

For tmux, and for socat using unix/unix-listen or
unix-sendto/unix-recv[from] it works fine, for
dtachhttp://dtach.sourceforge.net/ it
doesn't work. (doesnt show a terminal, just blank screen and keys not
working, detach key works ok though, detaching it.

Thanks for the fixes sofar! Awesome work! :-)

On Tue, Apr 9, 2013 at 4:55 AM, Cédric VINCENT notifications@github.comwrote:

Hello @hhm0 https://github.com/hhm0

Do you confirm the release v2.4.1 works as expected in this regard?

Regards,
Cedric.

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/8#issuecomment-16101330
.

[cedric-vincent]

Many thanks for all these tests! I'm able to reproduce the problem with dtach. I'll keep you informed.

[cedric-vincent]

As of my understanding, the issue with dtach under proot is due to the
fact that proot waits (for ptrace events) in the foreground, even if
all of its tracees were moved to the background. The problem is
reproducible with the code below: under proot, the terminal control is
never passed back to the parent shell, as it ought to be. In this
regard, proot is not transparent.

int main()
{
    daemon(0, 0);
    while (1)
        sleep(1);
    return 0;
}

I'll create a new entry for this issue.

Note: strace -f suffers the same issue.

[cedric-vincent]

The problem with dtach was moved to issue #11, feel free to re-open this issue if Unix domain sockets doesn't work as expected.

Thanks for your bug/test reports!

[pespin]

Please, implement this for sendto() too. I have a test case which works without proot but fails with proot as of v5.1.0:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <fcntl.h>
#include <strings.h>

int main(int argc, char *argv[]) {

        char * socket_path = "foobarSocket";

        // create
        int mSocketFD = socket(AF_UNIX,SOCK_DGRAM,0);
        if (mSocketFD<0) {
                perror("socket() failed");
                exit(1);
        }

        // bind
        struct sockaddr_un address;
        size_t length = sizeof(address);
        bzero(&address,length);
        address.sun_family = AF_UNIX;
        strcpy(address.sun_path, socket_path);
        unlink(socket_path);
        if (bind(mSocketFD,(struct sockaddr*)&address,length) < 0) {
                perror("bind() failed");
                exit(1);
        }

        //send info, will fail withj proot:
        int retVal = sendto(mSocketFD, "foobar", strlen("foobar"), 0,
                (struct sockaddr *)&address, sizeof(struct sockaddr_un));
        if (retVal == -1 ) {
                perror("sendto()) failed");
                exit(1);
        }
        printf("OK");
        return retVal;
}

[jopasserat]

Hi @pespin , thanks for reaching out!

Would you consider submitting a Pull Request?

[pespin]

Sure, I'll do it whenever I have some time soon if nobody does it before me.