man/man3c/lckpwdf.3c

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 lckpwdf 3C "29 Dec 1996" "SunOS 5.11" "Standard C Library Functions"
 NAME
lckpwdf, ulckpwdf - manipulate shadow password database lock file
 SYNOPSIS

#include <shadow.h>

int lckpwdf(void);


int ulckpwdf(void);


 DESCRIPTION

The lckpwdf() and ulckpwdf() functions enable modification access
to the password databases through the lock file. A process first uses
lckpwdf() to lock the lock file, thereby gaining exclusive rights to
modify the /etc/passwd or /etc/shadow password database. See
passwd(4) and shadow(4). Upon completing modifications, a process
should release the lock on the lock file using ulckpwdf(). This mechanism
prevents simultaneous modification of the password databases. The lock file,
/etc/.pwd.lock, is used to coordinate modification access to the password
databases /etc/passwd and /etc/shadow.
 RETURN VALUES

If lckpwdf() is successful in locking the file within 15 seconds, it
returns 0. If unsuccessful (for example, /etc/.pwd.lock is already
locked), it returns -1.

If ulckpwdf() is successful in unlocking the file /etc/.pwd.lock,
it returns 0. If unsuccessful (for example, /etc/.pwd.lock is
already unlocked), it returns -1.
 USAGE

These routines are for internal use only; compatibility is not guaranteed.
 FILES

/etc/passwd

password database


/etc/shadow

shadow password database


/etc/.pwd.lock

lock file


 ATTRIBUTES

See attributes(5) for descriptions of the following attributes:


ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelMT-Safe


 SEE ALSO

getpwnam(3C), getspnam(3C), passwd(4), shadow(4),
attributes(5)