Openbsd support (#562)

[landryb]

Isnt perfect yet, but would be nice to merge early so that the work isnt lost. Basic functionality needed by end users work...

[benoitc]

+1

[giampaolo]

I took a look back at this and updated the code here:
https://github.com/giampaolo/psutil/tree/landryb-openbsd
What's missing:

• Process.open_files()'s path is an empty string; kif->f_mntonname refers to the mountpoint (useless), kif->unp_path is always empty. lsof somehow manages to do it.
• Process.memory_maps() is not implemented (see code sample here: https://github.com/Bluerise/OpenBSD-src/blob/master/usr.sbin/procmap/procmap.c).
• Process.cmdline() does not return the actual cmdline; we get things such as ['pflogd: [running] -s 160 -i pflog0 -f /var/log/pflog'], ['sshd: user@notty'] and ['smtpd: scheduler'].
• Process.num_ctx_switches()'s involuntary field is always 0; I suppose this means it is just not supported on OpenBSD so it's OK to skip this test.
• user@openbsd~/psutil$ python -c "import psutil; print psutil.Process(0).exe()"
  python: Invalid argument

DONE:

• Process.threads() returns EINVAL. (fixed in 67da39e)
• Process.memory_info().vms (aka kp.p_vm_map_size) is always 0. "ps" manages to show VMS somehow; as a last resort we might parse ps output (fixed in eeac17f).
• Process.cwd() is not implemented; couldn't find any way to determine this. lsof somehow manages to get this. (fixed in 0410205).
• Process.num_threads() is not implemented. (fixed in 2ce156b)
• Process.connetions() and net_connections()'s status is always None. (fixed in 5808a06)
• Process.connetions() and net_connections()'s addr is always None for IPv6 sockets. (fixed in de97900)

[giampaolo]

Process.cwd() implemented in 0410205

[landryb]

Thanks for picking up this, i admit it feel out of the radar since i had no time for it...

[giampaolo]

OK, I merged everything in here #709 and b4625ab.
Last remaining issues are:

• Process.memory_maps() is not supported
• Process.open_files() return empty paths (also FreeBSD has this problem)
• Process.exe() is not fully implemented and currently relies on cmdline()

[landryb]

as i already said several times, open_files() will never get implemented, the kernel won't provide such an API.

[landryb]

But yay for seeing this merged \o/

[giampaolo]

as i already said several times, open_files() will never get implemented, the kernel won't provide such an API.

Do you know if this is a kernel bug? We have the same problem on FreeBSD which does provide the necessary API but the path sometimes is empty. Also OpenBSD should provide it (kif->unp_path) and it's empty. Any internet reference which explains any of this is welcome.

[giampaolo]

@landryb can you please comment about this?

psutil/psutil/arch/bsd/openbsd.c

Line 743 in fc1e59d

// TODO: why?

[landryb]

Do you know if this is a kernel bug? We have the same problem on FreeBSD which does provide the necessary API but the path sometimes is empty. Also OpenBSD should provide it (kif->unp_path) and it's empty. Any internet reference which explains any of this is welcome.

This is not a bug, it's on purpose for 'privacy reasons'. As for kif->unp_path, it's not filled much, see http://bxr.su/search?q=unp_path&project=OpenBSD

The only information you can get is the inode (see http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man1/fstat.1 from which you can list open inodes for a process), from which you could theoretically do lookups in the filesystem but this is cumbersome.

$fstat -p 21801   
USER     CMD          PID   FD MOUNT        INUM MODE       R/W    SZ|DV
landry   xfce4-session 21801 text /         1147672 -r-xr-xr-x   r   189368
landry   xfce4-session 21801   wd /home    29491840 drwxr-xr-x   r     7680
landry   xfce4-session 21801    0 /         1716753 crw-rw-rw-  rw     null
landry   xfce4-session 21801    1 /home    29496358 -rw-r--r--   w   407233
landry   xfce4-session 21801    2 /home    29496358 -rw-r--r--   w   407233
landry   xfce4-session 21801    3 /          572089 -rw-r--r--   w     2643
landry   xfce4-session 21801    4* unix stream 0x0
landry   xfce4-session 21801    5 pipe 0x0 state: 
landry   xfce4-session 21801    6 pipe 0x0 state: 
landry   xfce4-session 21801    7* unix stream 0x0
landry   xfce4-session 21801    8* unix stream 0x0
landry   xfce4-session 21801    9 /home    29492111 -rw-r--r--   w    11834
landry   xfce4-session 21801   10 pipe 0x0 state: 
landry   xfce4-session 21801   11 pipe 0x0 state: 
landry   xfce4-session 21801   12* unix stream 0x0
landry   xfce4-session 21801   13* unix stream 0x0
landry   xfce4-session 21801   14* unix stream 0x0
landry   xfce4-session 21801   15* unix stream 0x0
landry   xfce4-session 21801   16* unix stream 0x0
landry   xfce4-session 21801   17* unix stream 0x0

@landryb can you please comment about this?

psutil/psutil/arch/bsd/openbsd.c

Line 743 in fc1e59d

// TODO: why?

struct diskstats doesnt provide a breakdown between read and write time i think, see
http://bxr.su/OpenBSD/sys/sys/disk.h#62

[landryb]

As for the open files, the OS providing this information have to keep a cache of fd/inode/path around, and update it if the file is moved/hardlinked/etc - OpenBSD just doesnt do this.