endpwent



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


NAME

     getpwent, setpwent, endpwent - sequential password database access


SYNOPSIS

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

     struct passwd *
     getpwent(void);

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

     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     open as the database will become out of date if it is updated while the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.  Furthermore, programs that run child processes
     should be careful to call endpwent() to close these descriptors before
     calling execve(2) or system(3).

     setpwent() causes getpwent() to ``rewind'' to the beginning of the
     database.

     The endpwent() function closes any file descriptors opened by setpwent()
     or getpwent().

     These routines have been written to ``shadow'' the password file, that
     is, allow 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
     returned, otherwise, the password field of the returned structure will
     point to the string `*'.


YP SUPPORT

     If YP is active, getpwent() also uses the master.passwd.byname YP map (if
     available) or the passwd.byname YP map.  This is in addition to the
     passwd file, and respects the order of both normal and YP entries in the
     passwd file.


RETURN VALUES

     The getpwent() function returns a valid pointer to a passwd structure on
     success or a null pointer if end-of-file is reached or an error occurs.

     The endpwent() and setpwent() functions have no return value.


FILES

     /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


SEE ALSO

     getlogin(2), getgrent(3), getgrouplist(3), getpwnam(3), pw_dup(3),
     passwd(5), Makefile.yp(8), pwd_mkdb(8), vipw(8), yp(8)


HISTORY

     The getpwent(), setpwent(), and endpwent() functions appeared in
     Version 7 AT&T UNIX.

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


BUGS

     The getpwent() function stores its results in an internal static buffer
     and returns a pointer to that buffer.  Subsequent calls to getpwent(),
     getpwnam(), or getpwuid() will overwrite the same buffer.

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

OpenBSD 5.4                      June 5, 2013                      OpenBSD 5.4

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