lckpwdf(3C) Standard C Library Functions lckpwdf(3C)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 lck‐
pwdf() to lock the lock file, thereby gaining exclusive rights to mod‐
ify 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 pass‐
word 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 guaran‐
teed.
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 TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOgetpwnam(3C), getspnam(3C), passwd(4), shadow(4), attributes(5)SunOS 5.10 29 Dec 1996 lckpwdf(3C)
