xref: /dragonfly/lib/libc/gen/getpwent.3 (revision b40e316c) 
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32.\"     From: @(#)getpwent.3	8.2 (Berkeley) 12/11/93
33.\" $FreeBSD: src/lib/libc/gen/getpwent.3,v 1.11.2.5 2002/02/01 15:51:16 ru Exp $
34.\" $DragonFly: src/lib/libc/gen/getpwent.3,v 1.2 2003/06/17 04:26:42 dillon Exp $
35.\"
36.Dd September 20, 1994
37.Dt GETPWENT 3
38.Os
39.Sh NAME
40.Nm getpwent ,
41.Nm getpwnam ,
42.Nm getpwuid ,
43.Nm setpassent ,
44.Nm setpwent ,
45.Nm endpwent
46.Nd password database operations
47.Sh LIBRARY
48.Lb libc
49.Sh SYNOPSIS
50.In sys/types.h
51.In pwd.h
52.Ft struct passwd *
53.Fn getpwent void
54.Ft struct passwd *
55.Fn getpwnam "const char *login"
56.Ft struct passwd *
57.Fn getpwuid "uid_t uid"
58.Ft int
59.Fn setpassent "int  stayopen"
60.Ft void
61.Fn setpwent void
62.Ft void
63.Fn endpwent void
64.Sh DESCRIPTION
65These functions
66operate on the password database file
67which is described
68in
69.Xr passwd 5 .
70Each entry in the database is defined by the structure
71.Ar passwd
72found in the include
73file
74.Aq Pa pwd.h :
75.Bd -literal -offset indent
76struct passwd {
77	char	*pw_name;	/* user name */
78	char	*pw_passwd;	/* encrypted password */
79	uid_t	pw_uid;		/* user uid */
80	gid_t	pw_gid;		/* user gid */
81	time_t	pw_change;	/* password change time */
82	char	*pw_class;	/* user access class */
83	char	*pw_gecos;	/* Honeywell login info */
84	char	*pw_dir;	/* home directory */
85	char	*pw_shell;	/* default shell */
86	time_t	pw_expire;	/* account expiration */
87	int	pw_fields;	/* internal: fields filled in */
88};
89.Ed
90.Pp
91The functions
92.Fn getpwnam
93and
94.Fn getpwuid
95search the password database for the given login name or user uid,
96respectively, always returning the first one encountered.
97.Pp
98The
99.Fn getpwent
100function
101sequentially reads the password database and is intended for programs
102that wish to process the complete list of users.
103.Pp
104The
105.Fn setpassent
106function
107accomplishes two purposes.
108First, it causes
109.Fn getpwent
110to ``rewind'' to the beginning of the database.
111Additionally, if
112.Fa stayopen
113is non-zero, file descriptors are left open, significantly speeding
114up subsequent accesses for all of the routines.
115(This latter functionality is unnecessary for
116.Fn getpwent
117as it doesn't close its file descriptors by default.)
118.Pp
119It is dangerous for long-running programs to keep the file descriptors
120open as the database will become out of date if it is updated while the
121program is running.
122.Pp
123The
124.Fn setpwent
125function
126is identical to
127.Fn setpassent
128with an argument of zero.
129.Pp
130The
131.Fn endpwent
132function
133closes any open files.
134.Pp
135These routines have been written to ``shadow'' the password file, e.g.\&
136allow only certain programs to have access to the encrypted password.
137If the process which calls them has an effective uid of 0, the encrypted
138password will be returned, otherwise, the password field of the returned
139structure will point to the string
140.Ql * .
141.Sh YP/NIS INTERACTION
142When the
143.Xr yp 8
144password database is enabled, the
145.Fn getpwnam
146and
147.Fn getpwuid
148functions use the YP maps
149.Dq Li passwd.byname
150and
151.Dq Li passwd.byuid ,
152respectively, if the requested password entry is not found in the
153local database.  The
154.Fn getpwent
155function will step through the YP map
156.Dq Li passwd.byname
157if the entire map is enabled as described in
158.Xr passwd 5 .
159.Sh RETURN VALUES
160The functions
161.Fn getpwent ,
162.Fn getpwnam ,
163and
164.Fn getpwuid ,
165return a valid pointer to a passwd structure on success
166and a null pointer if end-of-file is reached or an error occurs.
167The
168.Fn setpassent
169function returns 0 on failure and 1 on success.
170The
171.Fn endpwent
172and
173.Fn setpwent
174functions
175have no return value.
176.Sh FILES
177.Bl -tag -width /etc/master.passwd -compact
178.It Pa /etc/pwd.db
179The insecure password database file
180.It Pa /etc/spwd.db
181The secure password database file
182.It Pa /etc/master.passwd
183The current password file
184.It Pa /etc/passwd
185A Version 7 format password file
186.El
187.Sh SEE ALSO
188.Xr getlogin 2 ,
189.Xr getgrent 3 ,
190.Xr passwd 5 ,
191.Xr pwd_mkdb 8 ,
192.Xr vipw 8 ,
193.Xr yp 8
194.Sh HISTORY
195The
196.Fn getpwent ,
197.Fn getpwnam ,
198.Fn getpwuid ,
199.Fn setpwent ,
200and
201.Fn endpwent
202functions appeared in
203.At v7 .
204The
205.Fn setpassent
206function appeared in
207.Bx 4.3 Reno .
208.Sh COMPATIBILITY
209The historic function
210.Xr setpwfile 3 ,
211which allowed the specification of alternate password databases,
212has been deprecated and is no longer available.
213.Sh BUGS
214The functions
215.Fn getpwent ,
216.Fn getpwnam ,
217and
218.Fn getpwuid ,
219leave their results in an internal static object and return
220a pointer to that object.
221Subsequent calls to
222the same function
223will modify the same object.
224