os.getlogin() not working

[ManickarajaKumarappan]

BPO	40821
Nosy	@tiran, @mephinet

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2021-12-10.11:54:44.241>
created_at = <Date 2020-05-29.20:31:30.406>
labels = ['extension-modules', 'invalid', 'type-bug', '3.7']
title = 'os.getlogin() not working'
updated_at = <Date 2021-12-10.11:54:44.241>
user = 'https://bugs.python.org/ManickarajaKumarappan'

bugs.python.org fields:

activity = <Date 2021-12-10.11:54:44.241>
actor = 'iritkatriel'
assignee = 'none'
closed = True
closed_date = <Date 2021-12-10.11:54:44.241>
closer = 'iritkatriel'
components = ['Extension Modules']
creation = <Date 2020-05-29.20:31:30.406>
creator = 'Manickaraja Kumarappan'
dependencies = []
files = []
hgrepos = []
issue_num = 40821
keywords = []
message_count = 3.0
messages = ['370336', '370369', '383161']
nosy_count = 3.0
nosy_names = ['christian.heimes', 'mephinet', 'Manickaraja Kumarappan']
pr_nums = []
priority = 'normal'
resolution = 'not a bug'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue40821'
versions = ['Python 3.7']

[ManickarajaKumarappan]

Hi,
We are using below command to get the original login user. In some cases folks sudo as different user and run commands. In some cases folks use switch to different user (su - <>) and then run command. In all cases we would like to get original user who logged into the terminal to run the command. We are using below command to get the same.

user=os.getlogin()

We got three RHEL linux systems with Python 3 and strangely on two of them this command works fine. However only on third system it is failing with below error

OSError: [Errno 6] No such device or address

Not sure if it is some o/s env setup which is causing this command to fail. Any pointers to run this command will be of great help so that we can pin point the issue.

Please note on faiing system if I do python and then run the command it works fine without any issue. However if it is triggered through our Scheduler (Control M) it is failing with above message.

Give below is the command how Scheduler triggers the job.

/bin/su - edwadm -c /bin/sh -x <>

Thanks
Manick.

[tiran]

On POSIX os.getlogin() is a thin wrapper around the glibc function getlogin() https://linux.die.net/man/3/getlogin . The error is coming from glibc.

[tiran]

errno 6 is ENXIO. According to https://www.man7.org/linux/man-pages/man3/getlogin.3.html the error code means "The calling process has no controlling terminal.".

os.getlogin() returns the name of the user logged in on the controlling terminal of the process. Typically processes in user session (tty, X session) have a controlling terminal. Processes spawned by a service manager like init, systemd, or upstart usually do not have a controlling terminal. You have to get the user information by other means. Our documentation for os.getlogin() recommends getpass.getuser().