xref: /freebsd/lib/libc/gen/getpwent.3 (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
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32.\"     From: @(#)getpwent.3	8.2 (Berkeley) 12/11/93
33.\" $FreeBSD$
34.\"
35.Dd September 20, 1994
36.Dt GETPWENT 3
37.Os
38.Sh NAME
39.Nm getpwent ,
40.Nm getpwnam ,
41.Nm getpwuid ,
42.Nm setpassent ,
43.Nm setpwent ,
44.Nm endpwent
45.Nd password database operations
46.Sh SYNOPSIS
47.Fd #include <sys/types.h>
48.Fd #include <pwd.h>
49.Ft struct passwd *
50.Fn getpwent void
51.Ft struct passwd *
52.Fn getpwnam "const char *login"
53.Ft struct passwd *
54.Fn getpwuid "uid_t uid"
55.Ft int
56.Fn setpassent "int  stayopen"
57.Ft void
58.Fn setpwent void
59.Ft void
60.Fn endpwent void
61.Sh DESCRIPTION
62These functions
63operate on the password database file
64which is described
65in
66.Xr passwd 5 .
67Each entry in the database is defined by the structure
68.Ar passwd
69found in the include
70file
71.Aq Pa pwd.h :
72.Bd -literal -offset indent
73struct passwd {
74	char	*pw_name;	/* user name */
75	char	*pw_passwd;	/* encrypted password */
76	uid_t	pw_uid;		/* user uid */
77	gid_t	pw_gid;		/* user gid */
78	time_t	pw_change;	/* password change time */
79	char	*pw_class;	/* user access class */
80	char	*pw_gecos;	/* Honeywell login info */
81	char	*pw_dir;	/* home directory */
82	char	*pw_shell;	/* default shell */
83	time_t	pw_expire;	/* account expiration */
84	int	pw_fields;	/* internal: fields filled in */
85};
86.Ed
87.Pp
88The functions
89.Fn getpwnam
90and
91.Fn getpwuid
92search the password database for the given login name or user uid,
93respectively, always returning the first one encountered.
94.Pp
95The
96.Fn getpwent
97function
98sequentially reads the password database and is intended for programs
99that wish to process the complete list of users.
100.Pp
101The
102.Fn setpassent
103function
104accomplishes two purposes.
105First, it causes
106.Fn getpwent
107to ``rewind'' to the beginning of the database.
108Additionally, if
109.Fa stayopen
110is non-zero, file descriptors are left open, significantly speeding
111up subsequent accesses for all of the routines.
112(This latter functionality is unnecessary for
113.Fn getpwent
114as it doesn't close its file descriptors by default.)
115.Pp
116It is dangerous for long-running programs to keep the file descriptors
117open as the database will become out of date if it is updated while the
118program is running.
119.Pp
120The
121.Fn setpwent
122function
123is identical to
124.Fn setpassent
125with an argument of zero.
126.Pp
127The
128.Fn endpwent
129function
130closes any open files.
131.Pp
132These routines have been written to ``shadow'' the password file, e.g.
133allow only certain programs to have access to the encrypted password.
134If the process which calls them has an effective uid of 0, the encrypted
135password will be returned, otherwise, the password field of the returned
136structure will point to the string
137.Ql * .
138.Sh YP/NIS INTERACTION
139When the
140.Xr yp 4
141password database is enabled, the
142.Fn getpwnam
143and
144.Fn getpwuid
145functions use the YP maps
146.Dq Li passwd.byname
147and
148.Dq Li passwd.byuid ,
149respectively, if the requested password entry is not found in the
150local database.  The
151.Fn getpwent
152function will step through the YP map
153.Dq Li passwd.byname
154if the entire map is enabled as described in
155.Xr passwd 5 .
156.Sh RETURN VALUES
157The functions
158.Fn getpwent ,
159.Fn getpwnam ,
160and
161.Fn getpwuid ,
162return a valid pointer to a passwd structure on success
163and a null pointer if end-of-file is reached or an error occurs.
164The
165.Fn setpassent
166function returns 0 on failure and 1 on success.
167The
168.Fn endpwent
169and
170.Fn setpwent
171functions
172have no return value.
173.Sh FILES
174.Bl -tag -width /etc/master.passwd -compact
175.It Pa /etc/pwd.db
176The insecure password database file
177.It Pa /etc/spwd.db
178The secure password database file
179.It Pa /etc/master.passwd
180The current password file
181.It Pa /etc/passwd
182A Version 7 format password file
183.El
184.Sh SEE ALSO
185.Xr getlogin 2 ,
186.Xr getgrent 3 ,
187.Xr yp 4 ,
188.Xr passwd 5 ,
189.Xr pwd_mkdb 8 ,
190.Xr vipw 8
191.Sh HISTORY
192The
193.Fn getpwent ,
194.Fn getpwnam ,
195.Fn getpwuid ,
196.Fn setpwent,
197and
198.Fn endpwent
199functions appeared in
200.At v7 .
201The
202.Fn setpassent
203function appeared in
204.Bx 4.3 Reno .
205.Sh COMPATIBILITY
206The historic function
207.Xr setpwfile 3 ,
208which allowed the specification of alternate password databases,
209has been deprecated and is no longer available.
210.Sh BUGS
211The functions
212.Fn getpwent ,
213.Fn getpwnam ,
214and
215.Fn getpwuid ,
216leave their results in an internal static object and return
217a pointer to that object. Subsequent calls to
218the same function
219will modify the same object.
220