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C function to test existence of a login

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# 1  
Old 03-01-2008
Data C function to test existence of a login
Hi everybody,

I need to check in C program whether a given login is known on the system. Is there any system function that could do this ?

So far, all I could find is getpwnam(), which answers my problem by parsing the local password database. But won't work if a user is authenticated by other means (PAM, Kerberos, ...).

I am surprised not to have found anything on that topic, because any shell is able to resolve a user's HOME while doing the tilde expansion, but how is it done? I had a look at the shell C sources, but I am a bit lost. Also, I don't have a system with network authentication handy, so I can't ktrace /bin/sh while doing a tilde expansion to see what function is called...

Thanks in advance, any help much appreciated.

Xavier
# 2  
Old 03-04-2008
Did you check man wtmp or man wtmpx?
# 3  
Old 03-04-2008
Hi, the discussion has moved here, indeed:

https://www.unix.com/unix-advanced-ex...xistence+login

X.
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