2.11BSD/man/cat3/getpwnam.0

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



NAME
     getpwent, getpwnam, getpwuid, setpassent, setpwfile,
     setpwent, endpwent - get password file entries

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

     struct passwd *getpwent()

     struct passwd *getpwnam(login)
     char *login;

     struct passwd *getpwuid(uid)
     uid_t uid;

     int setpassent(stayopen)
     int stayopen;

     void setpwfile(file)
     char *file;

     int setpwent()

     void endpwent()

DESCRIPTION
     _G_e_t_p_w_e_n_t, _g_e_t_p_w_u_i_d, and _g_e_t_p_w_n_a_m each return a pointer to a
     structure containing the broken-out fields of a line in the
     password file.  This structure is defined by the include
     file <pwd.h>, and contains the following fields:

	  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 */
	  };

     These fields are more completely described in _p_a_s_s_w_d(5).

     _G_e_t_p_w_n_a_m and _g_e_t_p_w_u_i_d search the password database for a
     matching user name or user uid, respectively, returning the
     first one encountered.  Identical user names or user uids
     may result in undefined behavior.




Printed 11/26/99	February 23, 1989			1






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



     _G_e_t_p_w_e_n_t sequentially reads the password database and is
     intended for programs that wish to step through the complete
     list of users.

     All three routines will open the password file for reading,
     if necessary.

     _S_e_t_p_w_f_i_l_e changes the default password file to _f_i_l_e, thus
     allowing the use of alternate password files.

     _S_e_t_p_a_s_s_e_n_t opens the file or rewinds it if it is already
     open.  If _s_t_a_y_o_p_e_n is non-zero, file descriptors are left
     open, significantly speeding up subsequent calls.	This
     functionality is unnecessary for _g_e_t_p_w_e_n_t as it doesn't
     close its file descriptors by default.  It should also be
     noted that it is dangerous for long-running programs to use
     this functionality as the password file may be updated by
     _c_h_p_a_s_s(1), _p_a_s_s_w_d(1), or _v_i_p_w(8).

     _S_e_t_p_w_e_n_t is identical to _s_e_t_p_a_s_s_e_n_t with an argument of
     zero.

     _E_n_d_p_w_e_n_t 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.  This is done by using the
     _m_k_p_a_s_s_w_d(8) program, which creates _n_d_b_m(3) databases that
     correspond to the password file, with the single exception
     that, rather than storing the encrypted password in the
     database, it stores the offset in the password file where
     the encrypted password may be found.  _G_e_t_p_w_e_n_t, _g_e_t_p_w_n_a_m,
     and _g_e_t_p_w_u_i_d will use the _n_d_b_m files in preference to the
     ``real'' password files, only reading the password file
     itself, to obtain the encrypted password, if the process is
     running with an effective user id equivalent to super-user.
     If the password file itself is protected, and the _n_d_b_m files
     are not, this makes the password available only to programs
     running with super-user privileges.

FILES
     /etc/passwd

SEE ALSO
     getlogin(3), getgrent(3), ndbm(3), passwd(5)

DIAGNOSTICS
     The routines _g_e_t_p_w_e_n_t, _g_e_t_p_w_n_a_m, and _g_e_t_p_w_u_i_d, return a null
     pointer on EOF or error.  _S_e_t_p_a_s_s_e_n_t and _s_e_t_p_w_e_n_t return 0
     on failure and 1 on success.  _E_n_d_p_w_e_n_t and _s_e_t_p_w_f_i_l_e have no
     return value.




Printed 11/26/99	February 23, 1989			2






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



BUGS
     All information is contained in a static buffer which is
     overwritten by each new call.  It must be copied elsewhere
     to be retained.

     Intermixing calls to _g_e_t_p_w_e_n_t with calls to _g_e_t_p_w_n_a_m or
     _g_e_t_p_w_u_i_d, or intermixing calls to _g_e_t_p_w_n_a_m and _g_e_t_p_w_u_i_d,
     after using _s_e_t_p_a_s_s_e_n_t to require that file descriptors be
     left open, may result in undefined behavior.

     The routines _g_e_t_p_w_e_n_t, _e_n_d_p_w_e_n_t, _s_e_t_p_a_s_s_e_n_t, and _s_e_t_p_w_e_n_t
     are fairly useless in a networked environment and should be
     avoided, if possible.










































Printed 11/26/99	February 23, 1989			3