xref: /freebsd/lib/libc/gen/getpwent.3 (revision 953a3198a35204535cc9d450f04da982a4fea59b)
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32.\"     From: @(#)getpwent.3	8.2 (Berkeley) 12/11/93
33.\"
34.Dd September 20, 1994
35.Dt GETPWENT 3
36.Os
37.Sh NAME
38.Nm getpwent ,
39.Nm getpwnam ,
40.Nm getpwuid ,
41.Nm setpassent ,
42.Nm setpwent ,
43.Nm endpwent
44.Nd password database operations
45.Sh SYNOPSIS
46.Fd #include <sys/types.h>
47.Fd #include <pwd.h>
48.Ft struct passwd *
49.Fn getpwent void
50.Ft struct passwd *
51.Fn getpwnam "const char *login"
52.Ft struct passwd *
53.Fn getpwuid "uid_t uid"
54.Ft int
55.Fn setpassent "int  stayopen"
56.Ft int
57.Fn setpwent void
58.Ft void
59.Fn endpwent void
60.Sh DESCRIPTION
61These functions
62operate on the password database file
63which is described
64in
65.Xr passwd 5 .
66Each entry in the database is defined by the structure
67.Ar passwd
68found in the include
69file
70.Aq Pa pwd.h :
71.Bd -literal -offset indent
72struct passwd {
73	char	*pw_name;	/* user name */
74	char	*pw_passwd;	/* encrypted password */
75	uid_t	pw_uid;		/* user uid */
76	gid_t	pw_gid;		/* user gid */
77	time_t	pw_change;	/* password change time */
78	char	*pw_class;	/* user access class */
79	char	*pw_gecos;	/* Honeywell login info */
80	char	*pw_dir;	/* home directory */
81	char	*pw_shell;	/* default shell */
82	time_t	pw_expire;	/* account expiration */
83};
84.Ed
85.Pp
86The functions
87.Fn getpwnam
88and
89.Fn getpwuid
90search the password database for the given login name or user uid,
91respectively, always returning the first one encountered.
92.Pp
93The
94.Fn getpwent
95function
96sequentially reads the password database and is intended for programs
97that wish to process the complete list of users.
98.Pp
99The
100.Fn setpassent
101function
102accomplishes two purposes.
103First, it causes
104.Fn getpwent
105to ``rewind'' to the beginning of the database.
106Additionally, if
107.Fa stayopen
108is non-zero, file descriptors are left open, significantly speeding
109up subsequent accesses for all of the routines.
110(This latter functionality is unnecessary for
111.Fn getpwent
112as it doesn't close its file descriptors by default.)
113.Pp
114It is dangerous for long-running programs to keep the file descriptors
115open as the database will become out of date if it is updated while the
116program is running.
117.Pp
118The
119.Fn setpwent
120function
121is identical to
122.Fn setpassent
123with an argument of zero.
124.Pp
125The
126.Fn endpwent
127function
128closes any open files.
129.Pp
130These routines have been written to ``shadow'' the password file, e.g.
131allow only certain programs to have access to the encrypted password.
132If the process which calls them has an effective uid of 0, the encrypted
133password will be returned, otherwise, the password field of the returned
134structure will point to the string
135.Ql * .
136.Sh YP/NIS INTERACTION
137When the
138.Xr yp 4
139password database is enabled, the
140.Fn getpwnam
141and
142.Fn getpwuid
143functions use the YP maps
144.Dq Li passwd.byname
145and
146.Dq Li passwd.byuid ,
147respectively, if the requested password entry is not found in the
148local database.  The
149.Fn getpwent
150function will step through the YP map
151.Dq Li passwd.byname
152if the entire map is enabled as described in
153.Xr passwd 5 .
154.Sh RETURN VALUES
155The functions
156.Fn getpwent ,
157.Fn getpwnam ,
158and
159.Fn getpwuid ,
160return a valid pointer to a passwd structure on success
161and a null pointer if end-of-file is reached or an error occurs.
162The functions
163.Fn setpassent
164and
165.Fn setpwent
166return 0 on failure and 1 on success.
167The
168.Fn endpwent
169function
170has no return value.
171.Sh FILES
172.Bl -tag -width /etc/master.passwd -compact
173.It Pa /var/db/pwd.db
174The insecure password database file
175.It Pa /var/db/spwd.db
176The secure password database file
177.It Pa /etc/master.passwd
178The current password file
179.It Pa /etc/passwd
180A Version 7 format password file
181.El
182.Sh SEE ALSO
183.Xr getlogin 3 ,
184.Xr getgrent 3 ,
185.Xr passwd 5 ,
186.Xr pwd_mkdb 8 ,
187.Xr vipw 8 ,
188.Xr yp 4
189.Sh HISTORY
190The
191.Nm getpwent ,
192.Nm getpwnam ,
193.Nm getpwuid ,
194.Nm setpwent,
195and
196.Nm endpwent
197functions appeared in
198.At v7 .
199The
200.Nm setpassent
201function appeared in
202.Bx 4.3 Reno .
203.Sh COMPATIBILITY
204The historic function
205.Xr setpwfile 3 ,
206which allowed the specification of alternate password databases,
207has been deprecated and is no longer available.
208.Sh BUGS
209The functions
210.Fn getpwent ,
211.Fn getpwnam ,
212and
213.Fn getpwuid ,
214leave their results in an internal static object and return
215a pointer to that object. Subsequent calls to
216the same function
217will modify the same object.
218