struct passwd {
char *pw_name; /* user name */
char *pw_passwd; /* encrypted password */
uid_t pw_uid; /* user uid */
gid_t pw_gid; /* user gid */
time_t pw_change; /* password change time */
char *pw_class; /* user access class */
char *pw_gecos; /* Honeywell login info */
char *pw_dir; /* home directory */
char *pw_shell; /* default shell */
time_t pw_expire; /* account expiration */
};
The functions Fn getpwnam and Fn getpwuid search the password database for the given login name or user uid, respectively, always returning the first one encountered.
The Fn getpwent function sequentially reads the password database and is intended for programs that wish to process the complete list of users.
The Fn setpassent function accomplishes two purposes. First, it causes Fn getpwent to ``rewind'' to the beginning of the database. Additionally, if Fa stayopen is non-zero, file descriptors are left open, significantly speeding up subsequent accesses for all of the routines. (This latter functionality is unnecessary for Fn getpwent as it doesn't close its file descriptors by default.)
It is dangerous for long-running programs to keep the file descriptors open as the database will become out of date if it is updated while the program is running.
The Fn setpwent function is equivalent to Fn setpassent with an argument of zero.
The Fn endpwent function closes any open files.
These routines have been written to ``shadow'' the password file, e.g. allow only certain programs to have access to the encrypted password. If the process which calls them has an effective uid of 0, the encrypted password will be returned, otherwise, the password field of the returned structure will point to the string `*'
The routines Fn getpwent , Fn endpwent , Fn setpassent , and Fn setpwent are fairly useless in a networked environment and should be avoided, if possible.