PW_LOCK(3) BSD Programmer's Manual PW_LOCK(3)
pw_lock, pw_mkdb, pw_abort - passwd file update functions
#include <util.h>
int
pw_lock(int retries);
int
pw_mkdb(char *username, int pwflags);
void
pw_abort();
The pw_lock(), pw_mkdb(), and pw_abort() functions allow a program to up-
date the system passwd database.
The pw_lock() function attempts to lock the passwd database by creating
the file /etc/ptmp with an exclusive lock (using flock(2) semantics) 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.
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 Version 7 format password
file (/etc/passwd).
By default the secure, insecure and Version 7 format password databases
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.
The pw_lock() and pw_mkdb() functions return -1 if they are unable to
complete properly.
/etc/master.passwd current password file
/etc/ptmp password lock file
/etc/passwd a Version 7 format password file
/etc/pwd.db insecure password database file
/etc/spwd.db secure password database file
flock(2), pw_init(3), pwd_mkdb(8)
MirBSD #10-current August 20, 2001 1