GETPWENT(3) MachTen Programmer’s Manual GETPWENT(3)

NAME
getpwent, getpwnam, getpwuid, setpassent, setpwent, endpwent - password
database operations

SYNOPSIS
#include <sys/types.h>
#include <pwd.h>

struct passwd *
getpwent(void)

struct passwd *
getpwnam(const char *login)

struct passwd *
getpwuid(uid_t uid)

int
setpassent(int stayopen)

int
setpwent(void)

void
endpwent(void)

DESCRIPTION
These functions operate on the password database file which is described
in passwd(5). Each entry in the database is defined by the structure
passwd found in the include file <pwd.h>:

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 getpwnam() and getpwuid() search the password database for
the given login name or user uid, respectively, always returning the
first one encountered.

The getpwent() function sequentially reads the password database and is
intended for programs that wish to process the complete list of users.

The setpassent() function accomplishes two purposes. First, it causes
getpwent() to ‘‘rewind’’ to the beginning of the database. Additionally,
if 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 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open as the database will become out of date if it is updated while the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 setpwent() function is identical to setpassent() with an argument of
zero.

The 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 ‘*’.

RETURN VALUES
The functions getpwent(), getpwnam(), and getpwuid(), return a valid
pointer to a passwd structure on success and a null pointer if end-of-
file is reached or an error occurs. The functions setpassent() and
setpwent() return 0 on failure and 1 on success. The endpwent() function
has no return value.

FILES
/var/db/pwd.db The insecure password database file
/var/db/spwd.db The secure password database file
/etc/master.passwd The current password file
/etc/passwd A Version 7 format password file

SEE ALSO
getlogin(3), getgrent(3), passwd(5), pwd_mkdb(8), vipw(8)

HISTORY
The getpwent, getpwnam, getpwuid, setpwent, and endpwent functions ap-
peared in Version 7 AT&T UNIX. The setpassent function appeared in
4.3BSD-Reno.

BUGS
The functions getpwent(), getpwnam(), and getpwuid(), leave their results
in an internal static object and return a pointer to that object. Subse-
quent calls to the same function will modify the same object.

The routines getpwent(), endpwent(), setpassent(), and setpwent() are
fairly useless in a networked environment and should be avoided, if pos-
sible.

COMPATIBILITY
The historic function setpwfile(3), which allowed the specification of
alternate password databases, has been deprecated and is no longer avail-
able.

4.4BSD December 11, 1993 2