shm_open doesn't work

[beelzetron]

Hi,
when I run a playbook inside the fedora-toolbox created container it returns the following error:
ERROR! Unable to use multiprocessing, this is normally caused by lack of access to /dev/shm: [Errno 30] Read-only file system

[debarshiray]

I can reproduce this with:

/* gcc shm.c -lrt */

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>

int
main (void)
{
  int fd;

  fd = shm_open ("/foo", O_CREAT | O_RDWR, 0664);
  if (fd == -1)
    {
      fprintf (stderr, "shm_open failed: %s\n", strerror (errno));
      return 1;
    }

  close (fd);
  return 0;
}

However, this works:

🔹[rishi@toolbox ~]$ echo hello world >/dev/shm/bar
🔹[rishi@toolbox ~]$ ls -l /dev/shm
total 4
-rw-rw-r--. 1 rishi rishi 12 Nov  6 18:48 bar
🔹[rishi@toolbox ~]$ cat /dev/shm/bar
hello world

[debarshiray]

That tells me that open works, but shm_open doesn't, which is not suprising because /dev/shm doesn't seem to be on a tmpfs:

🔹[rishi@toolbox ~]$ df -h /dev
Filesystem      Size  Used Avail Use% Mounted on
tmpfs            64M     0   64M   0% /dev
🔹[rishi@toolbox ~]$ df -h /dev/shm
Filesystem      Size  Used Avail Use% Mounted on
/dev/nvme0n1p5  415G   28G  366G   7% /dev/shm

[debarshiray]

Does PR #12 fix the problem for you?

[debarshiray]

I am closing this issue because the above shm_open reproducer now works for me. Feel free to reopen or leave a comment if you have reason to think otherwise.

Either way, thanks for trying fedora-toolbox and getting in touch!