11-17-2017
Quote:
Originally Posted by
bodisha
Thanks for the reply again... You sort of touched on the part of where I'm getting confused at. My understanding of a background process like a user ID for an Oracle database is it would be a non-interactive and non-login shell...
The shell is not actually in charge, it just helps arrange things. The shell isn't necessarily involved at all in creating the Oracle process, or creating any other process for that matter.
The one and only difference between "interactive" and "noninteractive" processes, as far as the kernel is concerned, is whether your process has a controlling terminal. The kernel knows what your terminal is even if your process doesn't - you can open it via /dev/tty. The kernel doesn't really
care whether you have a terminal.
In the old days terminals were really terminals - physical devices attached to serial ports. /bin/login did the job of holding those ports open and reading username/passwords from them. Each port would have one /bin/login process running for it. These days, things like ssh have mostly taken over the job of sitting around and waiting for user input, terminals have become imaginary devices which get created and destroyed at need.
The
login program creates your shell. It owns the terminal, and opens it, duplicating it onto file descriptors 0, 1, and 2 for you - standard input, standard output, and standard error. Then
login runs your shell and lets it take over from there.
Quote:
It specifies a script and not a process... Which makes me wonder how does a background process owned get the environment.
When a process is created, it receives a copy of the environment of its parent. So it comes down to where the parent got
its environment.
Last edited by Corona688; 11-17-2017 at 07:00 PM..
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LEARN ABOUT HPUX
getlogin
getlogin(3C) getlogin(3C)
NAME
getlogin(), getlogin_r() - get name of user logged in on this terminal
SYNOPSIS
DESCRIPTION
The function retrieves the name of the user currently logged in on a terminal associated with the calling process, as found in user-
accounting database maintained by utmpd(1M).
At least one of the standard input, standard output, or standard error must be a terminal. For the first of these found that is a termi-
nal, a user must have logged in on that terminal, and that terminal must be the controlling terminal of the session leader process of the
calling process's session.
The function can be used in conjunction with to locate the correct password file entry when the same user ID is shared by several login
names.
The recommended procedure to obtain the user name associated with the real user ID of the calling process is to call and if that fails, to
call
To get the user name associated with the effective user ID, call
performs the same operations as but returns the login name in the buffer to which buf points, whose size in bytes should be passed in
buflen. buf should have space for the name and the terminating null character. The maximum size of the login name can be obtained using
the API with as the argument.
APPLICATION USAGE
The return value from points to static data whose content is overwritten by each call.
RETURN VALUE
Upon successfully finding and validating the login name of the user logged in on the terminal, returns a pointer to the name. Otherwise,
it returns a null pointer, and sets to indicate the error.
Upon successfully finding, validating, and copying to the buffer the login name of the user logged in on the terminal, returns 0 upon suc-
cess and returns an error number upon failure.
ERRORS
and fail if any of the following is true:
[EACCES] Access permission to get the status of the terminal device file, was denied.
[EMFILE] Too many file descriptors are in use by this process.
[ENFILE] Too many file descriptors are in use on the system.
[ENOENT] The terminal device file cannot be found.
[ENOTTY] None of the standard input, standard output, or standard error is a terminal, or for the first of these that is a
terminal, no current login is registered on that terminal, or the session leader process of the calling process has
no controlling terminal.
[EPERM] One of the standard input, standard output, or standard error is a terminal, and a current login was found on that
terminal, but that terminal is not the same as the controlling terminal of the session of the calling process.
[ESRCH] The session leader process of the calling process is no longer running.
The error condition associated with [EPERM] prevents processes that have access to some other user's terminal from believing that they are
related to that other user's login session.
also fails if the following is true:
[ERANGE] The length of the name to be returned, including the terminating null byte, exceeds buflen.
WARNINGS
Users of should note now conforms with the POSIX.1c Threads standard. The old prototype of is supported for compatibility with existing
DCE applications only.
SEE ALSO
utmpd(1M), getuid(2), sysconf(2), getgrent(3C), getpwent(3C), thread_safety(5).
STANDARDS CONFORMANCE
getlogin(3C)