Does a user have to log in to run a process and become its owner?
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In general, does a user have to log in to run a process and become its owner (ruid, or euid)? Does this apply to any user or any non-root user?
For example:
In the boot sequence of Linux, the kernel starts the init system as the first process, and then the init process runs
loginso that each user can login.
The init process is owned byroot, and does the userroothave to log in before starting theinitprocess? See Why is there a `systemd` process owned by each user that is logged in?When using
sshto run a command without starting an interactive shell, do we have to log in first or not to run the command?
If I don't need to log in to run a process as its owner, how can I do that?
Thanks.
linux process users root
asked Dec 19 at 13:13
Tim
26k74246455
add a comment |
In general, does a user have to log in to run a process and become its owner (ruid, or euid)? Does this apply to any user or any non-root user?
For example:
In the boot sequence of Linux, the kernel starts the init system as the first process, and then the init process runs
loginso that each user can login.
The init process is owned byroot, and does the userroothave to log in before starting theinitprocess? See Why is there a `systemd` process owned by each user that is logged in?When using
sshto run a command without starting an interactive shell, do we have to log in first or not to run the command?
If I don't need to log in to run a process as its owner, how can I do that?
Thanks.
linux process users root
asked Dec 19 at 13:13
Tim
26k74246455
When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may beinitor another process) and there may be some child processes. I'm not sure what you mean by "owner"...
– Stephen Harris
Dec 19 at 15:04
add a comment |
In general, does a user have to log in to run a process and become its owner (ruid, or euid)? Does this apply to any user or any non-root user?
For example:
In the boot sequence of Linux, the kernel starts the init system as the first process, and then the init process runs
loginso that each user can login.
The init process is owned byroot, and does the userroothave to log in before starting theinitprocess? See Why is there a `systemd` process owned by each user that is logged in?When using
sshto run a command without starting an interactive shell, do we have to log in first or not to run the command?
If I don't need to log in to run a process as its owner, how can I do that?
Thanks.
linux process users root
asked Dec 19 at 13:13
Tim
26k74246455
In general, does a user have to log in to run a process and become its owner (ruid, or euid)? Does this apply to any user or any non-root user?
For example:
In the boot sequence of Linux, the kernel starts the init system as the first process, and then the init process runs
loginso that each user can login.
The init process is owned byroot, and does the userroothave to log in before starting theinitprocess? See Why is there a `systemd` process owned by each user that is logged in?When using
sshto run a command without starting an interactive shell, do we have to log in first or not to run the command?
If I don't need to log in to run a process as its owner, how can I do that?
Thanks.
linux process users root
linux process users root
asked Dec 19 at 13:13
Tim
26k74246455
asked Dec 19 at 13:13
Tim
26k74246455
edited Dec 19 at 15:38
asked Dec 19 at 13:13
Tim
26k74246455
asked Dec 19 at 13:13
Tim
26k74246455
asked Dec 19 at 13:13
Tim
26k74246455
26k74246455
When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may beinitor another process) and there may be some child processes. I'm not sure what you mean by "owner"...
– Stephen Harris
Dec 19 at 15:04
add a comment |
When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may beinitor another process) and there may be some child processes. I'm not sure what you mean by "owner"...
– Stephen Harris
Dec 19 at 15:04
When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may be
init or another process) and there may be some child processes. I'm not sure what you mean by "owner"...– Stephen Harris
Dec 19 at 15:04
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may be
init or another process) and there may be some child processes. I'm not sure what you mean by "owner"...– Stephen Harris
Dec 19 at 15:04
add a comment |
1 Answer
1
active
oldest
votes
No, you don’t need to log in to start a process running as a given user. Logging in is a user-space construct; the kernel doesn’t care about that. There are multiple examples of this; for example, cron jobs can run as any user, without that user being logged in.
To address your specific questions:
- no, root doesn’t need to log in to start the
initprocess, thankfully (imagine handling a fleet of thousands of servers and millions of VMs otherwise); - connecting using SSH counts as logging in.
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
add a comment |
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1 Answer
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1 Answer
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oldest
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No, you don’t need to log in to start a process running as a given user. Logging in is a user-space construct; the kernel doesn’t care about that. There are multiple examples of this; for example, cron jobs can run as any user, without that user being logged in.
To address your specific questions:
- no, root doesn’t need to log in to start the
initprocess, thankfully (imagine handling a fleet of thousands of servers and millions of VMs otherwise); - connecting using SSH counts as logging in.
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
add a comment |
No, you don’t need to log in to start a process running as a given user. Logging in is a user-space construct; the kernel doesn’t care about that. There are multiple examples of this; for example, cron jobs can run as any user, without that user being logged in.
To address your specific questions:
- no, root doesn’t need to log in to start the
initprocess, thankfully (imagine handling a fleet of thousands of servers and millions of VMs otherwise); - connecting using SSH counts as logging in.
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
add a comment |
No, you don’t need to log in to start a process running as a given user. Logging in is a user-space construct; the kernel doesn’t care about that. There are multiple examples of this; for example, cron jobs can run as any user, without that user being logged in.
To address your specific questions:
- no, root doesn’t need to log in to start the
initprocess, thankfully (imagine handling a fleet of thousands of servers and millions of VMs otherwise); - connecting using SSH counts as logging in.
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
No, you don’t need to log in to start a process running as a given user. Logging in is a user-space construct; the kernel doesn’t care about that. There are multiple examples of this; for example, cron jobs can run as any user, without that user being logged in.
To address your specific questions:
- no, root doesn’t need to log in to start the
initprocess, thankfully (imagine handling a fleet of thousands of servers and millions of VMs otherwise); - connecting using SSH counts as logging in.
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
answered Dec 19 at 13:24
Stephen Kitt
164k24365444
164k24365444
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
add a comment |
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
Thanks. If I want run a process as its owner without logging in, how can I do that? Is the only way to call setuid() or seteuid() in the program run by the process?
– Tim
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
That’s another question.
– Stephen Kitt
Dec 19 at 13:39
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
Could you explain what you meant by "logging in"? That has led to several other questions.
– Tim
Dec 21 at 1:34
add a comment |
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When you SSH into a machine, you provide credentials (either by password or public key) to prove that you have adequate access right to the system as the user that you say you are. This constitutes a logging in. As for the first question, do you know the difference between a service account and an account for an interactive user? See e.g. What is the difference between user and service account?
– Kusalananda
Dec 19 at 13:19
Thanks. How can a service user start a process as its owner or become its owner later?
– Tim
Dec 19 at 14:08
What do you mean by "owner" in this context? A process runs under a uid, has a primary gid, a set of secondary gids, potentially a set of capabilities. There is a parent process (which may be
initor another process) and there may be some child processes. I'm not sure what you mean by "owner"...– Stephen Harris
Dec 19 at 15:04