PW_LOCK(3)

NAME
pw_lock, pw_mkdb, pw_abort - passwd file update functions

SYNOPSIS
#include <util.h>
int
pw_lock(int retries);
int
pw_mkdb(char *username, int pwflags);
void
pw_abort(void);

DESCRIPTION
The pw_lock(), pw_mkdb(), and pw_abort() functions allow a program to update the system passwd database.

The pw_lock() function attempts to lock the passwd database by creating the file /etc/ptmp, and returns the file descriptor of that file. If retries is greater than zero, pw_lock() will try multiple times to open /etc/ptmp, waiting one second between tries. In addition to being a lock file, /etc/ptmp will also hold the contents of the new passwd file. A different lock file can be specified with pw_file(3).

pw_init(3) must be called before pw_lock().

The pw_mkdb() function updates the passwd file from the contents of /etc/ptmp via pwd_mkdb(8). If a username is specified, only the record for the specified user will be updated. The pwflags are specified by OR'ing the following values:

_PASSWORD_SECUREONLY
    only update the secure database file (/etc/spwd.db).
_PASSWORD_OMITV7
    do not update the legacy password file (/etc/passwd).

By default the secure and insecure password databases and the legacy password file /etc/passwd are updated. You should finish writing to and close the file descriptor returned by pw_lock() before calling pw_mkdb(). If pw_mkdb() fails and you do not wish to retry, you should make sure to call pw_abort() to clean up the lock file.

The pw_abort() function aborts a passwd file update by deleting /etc/ptmp. The passwd database remains unchanged.

RETURN VALUES
The pw_lock() function returns -1 on error and sets errno. The pw_mkdb() function returns -1 if it is unable to complete properly.

FILES
/etc/master.passwd
    Current password file.
/etc/passwd
    Legacy password file.
/etc/ptmp
    Password lock file.
/etc/pwd.db
    Insecure password database file.
/etc/spwd.db
    Secure password database file.

ERRORS

[EINVAL]
    pw_lock() was called before pw_init(3).

pw_lock() may also fail and set errno for any of the errors specified for the routine open(2).

SEE ALSO
pw_file(3), pw_init(3), pwd_mkdb(8)