I have a problem reconnecting to ISPF. After the TSO/E LOGON screen, the screen on the attached picture shows and says that logon reconnection is successful, but it doesn't proceed to ISPF. If I type any commands, ISPF, logoff, etc. it locks.
Make sure you are connecting with the same terminal settings(mod5, mod2, etc).
Sometime you need to use PA2 to force a rebuild of the current panel. If you disconnected while running a CLIST/EXEC/program, then you might need to ATTN out of it.
It could have been that you were in a process that was looping or hung, and you were simply reconnected to that looping/hanging process. Next time, try the ATTN key. I have seen some installations set up the logon screen/process where if you do not choose RECONNECT, your still-active prior session will be terminated prior to logging you on. This is a nice setup, especially for hang situations like you were probably in.
Related
I'm a beginner in Proxmox.
Actually, everything was working perfectly fine until I installed 2 additional hard disks in my server.
All of a sudden, I had an error mentioning that CPU was blocked for more then 25sec... I restarted and the server and now it's telling me that I'm in Emergency Mode...
I have 2 options:
Give root password for maintenance
press Control-D to continue
Control-D:
When I'm pressing control-D to continue it's saying: Reloading system manager configuration, starting default target. Then it starts asking the password for maintenance or press control-d... again and again...
Root Password
Is is the same password as the one I'm using to connect to the GUI? If that's the case, since I have a very long password with special characters, I need to see what I'm typing which is not the case by default... How can I check that?
What if I remove the 2 new additional hard disks ? Should it start normally ? Or I will still be in emergency mode ?
It's the same password and no, you cannot see what you are typing.
Remove drives, it should boot normally. You need to check and edit /etc/fstab so it's not using new drives as root. Maybe these two disks are not empty?
For a running script on a Linux VM with a regular console output: If I disconnect from the VM the output window disappears. If I restart the VM, the script is still running but how do I get back to the output-screen?
Easy solution: use GNU screen, or an alternative like tmux to run your scripts in a persistent session. Thus, if you accidentally disconnect from your SSH session (or must shut down your computer), you can still reattach to the screen session later.
Tutorial: Using GNU Screen to Manage Persistent Terminal Sessions
Another great feature is that screen can also log the console output to a file. I use it all the time for cron jobs or other unattended tasks. I also use screen for updates (using yum, dnf or whatever), because updates can take a lot of time, and sometimes may even have to restart the network service, which would terminate your SSH session.
If I open an ssh connection and start a long-running process, is there any way to close the ssh connection, and not only keep the process running, but be able to later ssh back in again, and "reattach" the process to the terminal?
I am able to do the following:
Ctrl-z
bg
disown
And that lets me keep the process running after I leave my ssh session, but I am not able to "reown" the job later; is there a way to do this? The real-world scenario is that I'd like to start a process at work, drive home, then log back in and check on it/interact with it.
I know that tmux is able to handle things like this, but I am often forgetful, or I just don't know ahead of time what process will be long-running and what won't, so I don't always remember to start the process from within tmux.
There are several ways to accomplish this. I used to use screen and that was a round about way of doing it. But check out mosh, built just for this: http://mosh.mit.edu/
I'm making a security software that is a parental control monitoring system and I don't want any user / administrator or a program to kill my process.
I have tried using SetSecurityInfo() but that didn't work. Then SetKernelObjectSecurity but that also didn't do what I wanted.
How would I do this?
I would also love to have a clear explanation of any code provided.
EDIT: If so, how do antivirus programs do it ???
Can you please help me. Im new to WINAPI I would like to know about something which is simple... Sorry to trouble you guys but at least you can show me the code for some 'watch dog' process or something . . .
This is not controlled by the process itself, and certainly not by its calling a magic API function. If it were, all malicious software would set itself up as "unkillable" and totally pwn your system. Rather, it is a security attribute of the executable file—specifically, the "Terminate" permission.
You can explore this for yourself by downloading Process Explorer:
Open the properties for your process
Switch to the "Security" tab
Click the "Permissions" button
Click the "Advanced" button
Select the desired user or group
Change the setting of the "Terminate" permission.
System processes have the "Terminate" permission denied to all users except the SYSTEM user. This is why even administrators receive the "Access Denied" message, because they lack the "Terminate" permission for system processes.
Of course, even setting this attribute correctly does not make the process "unkillable". It just makes it more difficult. There is plenty of software available online for a free download that allows users to kill such processes, and anyone with basic knowledge of the Windows security model can work around it without even requiring special software.
And none of this makes much sense for parental control software. You should be using the Windows security model to your advantage, not trying to work against it. Install the software as an administrator (i.e., the parent's account), and then set the child(ren) up with a limited user account. Limited user accounts won't be able to kill your process because they don't have the requisite permissions. If an administrator wants to kill your process, then you should let them, not give them some spurious "ACCESS DENIED" headache.
No it's not possible. No matter what you do, I can always turn the machine off.
First of all, lets make it clear it is impossible.
But, you can make it harder.
Besides, what "Code Gray" wrote I'm adding:
You can use another process to be a watchdog, and your process watches the watchdog as well (cyclic watchdog), so if one of you is being terminate, it re-runs the other one. You can bypass that by killing your process and the watchdog before any of them get the chance to start the other one.
1a. An attacker can freeze the process instead of terminating it, therefore (1) wouldn't work, so you can "ping" each other every N seconds, and if a ping is missing, something is wrong (not sure how to recover this, depends on the product).
If you are a service, you can set windows to recover your service once its down.
Just an idea, I would not do that in a product. You can API-hook an important function in an important process (a function that is being called quite a lot). Everytime the function is being called, check if your process is up, if not, REBOOT! :-P.
Another wild idea (That I wouldn't do in a product!!!), write a driver and look for a terminate event for your process. If it someone terminates your process, cause a blue screen! That will show 'em! 8-P
Good Luck!
Hooking NtTerminateProcess in kernel mode may helps you.
PS: Hook also NtTerminateThread, because I remember one version of NOD32 antivirus with dumb bug, when killing process was denied, but killing all threads was possible. :-)
On one of the servers I commonly work with (Ubuntu 11.04), I get a hanging logout whenever I do following:
Log in via SSH
Start screen
Run Vim
{edit files, etc}
Detach screen session
Log out of server ("exit")
After doing, it hangs. (says "logout", never seems to actually log out). Furthermore, the next time I log in and reattach my screen session, it seems that all of my key bindings are gone in Vim. This includes the entire functionality of some plugins, like NERDTree.
I tried a few different combinations of these actions. For example, if I exit Vim before detaching my screen, it doesn't do this. It also doesn't do this if I don't run Vim at all, or if I don't run screen at all.
Any idea what could be going on here?
I found out what the issue is. I had my SSH client configured to forward X for that server. Disabling that fixed the problem. I don't really understand the details of why, but that's what it is.