how init call login?

[frederick van tagero]

I think PAM is portable auth module, So it is only be called by init process, I think it could be init->login->pam, am I right?

but there is no login program, whether it is the login_utils?thanks for any tips.

Best Regards,
Frederick

[Goran Koruga · Accepted solution]

Well any application can use PAM, it's got nothing to do with init.

Many utilities that require authentication use PAM : FTP daemons, SSH daemon, telnet, rshd, POP3/IMAP daemons, screen
savers and so on.

G.

[Goran Koruga]

I forgot to answer your question.

login is usually started by getty, not by init.

G.

[Sergejs Svitnevs]

PAM (Pluggable Authentication Module) is a single executable binary file that can be loaded by the Linux-PAM interface library.

The init process doesn't call the PAM.

The service calls PAM, which at run-time determines which ``authentication modules'' are required by checking the configuration set by the local system administrator.

Example:
The init process spawns the getty process, the getty process invokes the login process.

The authentication process for login service specified via /etc/pam.d/login configuration file.

Regards,
Sergejs