1 /* Copyright (C) 1996 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Library General Public License as
7 published by the Free Software Foundation; either version 2 of the
8 License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Library General Public License for more details.
15 You should have received a copy of the GNU Library General Public
16 License along with the GNU C Library; see the file COPYING.LIB. If
17 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA. */
29 /* XXX An alternative solution would be to call a SUID root program
30 which write the new value. */
33 pututline_r (const struct utmp
*utmp_ptr
, struct utmp_data
*utmp_data
)
39 /* Test whether ID has any of the legal types because we have to
40 prevent illegal entries. */
41 if (id
->ut_type
!= RUN_LVL
&& id
->ut_type
!= BOOT_TIME
42 && id
->ut_type
!= OLD_TIME
&& id
->ut_type
!= NEW_TIME
43 && id
->ut_type
!= INIT_PROCESS
&& id
->ut_type
!= LOGIN_PROCESS
44 && id
->ut_type
!= USER_PROCESS
&& id
->ut_type
!= DEAD_PROCESS
)
45 /* No, using '<' and '>' for the test is not possible. */
52 /* Open utmp file if not already done. */
53 if (utmp_data
->ut_fd
== -1)
55 setutent_r (utmp_data
);
56 if (utmp_data
->ut_fd
== -1)
61 /* Seek position to write. */
62 if (utmp_data
->ubuf
.ut_type
!= utmp_ptr
->ut_type
)
64 /* We must not overwrite the data in UTMP_DATA. */
65 struct utmp_data
*data_tmp
= alloca (sizeof (utmp_data
));
69 *data_tmp
= *utmp_data
;
72 if (getutid_r (utmp_ptr
, &dummy
, utmp_data
) < 0)
75 /* Some error occured. If no entry was found, the position
76 pointer now is at the end of the file. */
79 /* Set position pointer to position after adding of the record. */
80 utmp_data
->loc_utmp
+= sizeof (struct utmp
);
84 /* Find out how large the file is. */
85 if (fstat (utmp_data
->ut_fd
, &st
) < 0)
88 /* Position file correctly. */
89 if (utmp_data
->loc_utmp
<= st
.st_size
90 && lseek (utmp_data
->ut_fd
, utmp_data
->loc_utmp
- sizeof (struct utmp
),
94 /* Try to lock the file. */
95 if (flock (utmp_data
->ut_fd
, LOCK_EX
| LOCK_NB
) < 0 && errno
!= ENOSYS
)
97 /* Oh, oh. The file is already locked. Wait a bit and try again. */
100 /* This time we ignore the error. */
101 (void) flock (utmp_data
->ut_fd
, LOCK_EX
| LOCK_NB
);
104 /* Write the new data. */
105 if (write (utmp_data
->ut_fd
, utmp_ptr
, sizeof (struct utmp
))
106 != sizeof (struct utmp
))
108 /* If we appended a new record this is only partially written.
110 if (utmp_data
->loc_utmp
> st
.st_size
)
112 (void) ftruncate (utmp_data
->ut_fd
, st
.st_size
);
113 utmp_data
->loc_utmp
= st
.st_size
;
119 /* And unlock the file. */
120 (void) flock (utmp_data
->ut_fd
, LOCK_UN
);