MirBSD manpage: endpwent(3), getpwent(3), getpwnam(3), getpwuid(3), setpassent(3), setpwent(3), setpwfile(3)

GETPWENT(3)                BSD Programmer's Manual                 GETPWENT(3)


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


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

     struct passwd *

     struct passwd *
     getpwnam(const char *login);

     struct passwd *
     getpwuid(uid_t uid);

     setpassent(int stayopen);




     These functions operate on the password database file which is described
     in passwd(5). Each entry in the database is defined by the structure
     struct 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 ID, respectively, always returning the first
     one encountered.

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

     setpassent() 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 sub-
     sequent accesses for all of the routines. (This latter functionality is
     unnecessary for getpwent() as it doesn't close its file descriptors by

     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     open as the database will become out of date if it is updated while the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.

     setpwent() is equivalent to setpassent() with an argument of zero.

     The endpwent() function closes any open files.

     These routines have been written to "shadow" the password file, i.e., al-
     low only certain programs to have access to the encrypted password. If
     the process which calls them has an effective UID of 0 or has the
     "_shadow" group in its group vector, the encrypted password will be re-
     turned, otherwise, the password field of the returned structure will
     point to the string '*'.


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


     /etc/pwd.db         insecure password database file
     /etc/spwd.db        secure password database file
     /etc/master.passwd  current password file
     /etc/passwd         a Version 7 format password file


     getlogin(2), getgrent(3), pw_dup(3), passwd(5), pwd_mkdb(8), vipw(8)


     The getpwent(), getpwnam(), getpwuid(), setpwent(), and endpwent() func-
     tions appeared in Version 7 AT&T UNIX. The setpassent() function appeared
     in 4.3BSD-Reno.

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


     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 any of these functions 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-

MirBSD #10-current            December 11, 1993                              1

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