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. */
30 /* XXX An alternative solution would be to call a SUID root program
31 which write the new value. */
34 __pututline_r (const struct utmp
*id
, struct utmp_data
*utmp_data
)
40 /* Test whether ID has any of the legal types because we have to
41 prevent illegal entries. */
42 if (id
->ut_type
!= RUN_LVL
&& id
->ut_type
!= BOOT_TIME
43 && id
->ut_type
!= OLD_TIME
&& id
->ut_type
!= NEW_TIME
44 && id
->ut_type
!= INIT_PROCESS
&& id
->ut_type
!= LOGIN_PROCESS
45 && id
->ut_type
!= USER_PROCESS
&& id
->ut_type
!= DEAD_PROCESS
)
46 /* No, using '<' and '>' for the test is not possible. */
53 /* Open utmp file if not already done. */
54 if (utmp_data
->ut_fd
== -1)
56 setutent_r (utmp_data
);
57 if (utmp_data
->ut_fd
== -1)
62 /* Check whether we need to reposition. Repositioning is necessary
63 either if the data in UTMP_DATA is not valid or if the ids don't
66 && (utmp_data
->loc_utmp
< (off_t
) sizeof (struct utmp
)
67 || strncmp (utmp_data
->ubuf
.ut_id
, id
->ut_id
,
68 sizeof (id
->ut_id
)) != 0))
70 /* We must not overwrite the data in UTMP_DATA since ID may be
72 struct utmp_data
*data_tmp
= alloca (sizeof (*data_tmp
));
75 *data_tmp
= *utmp_data
;
78 if (getutid_r (id
, &dummy
, utmp_data
) < 0 && errno
!= ESRCH
)
83 /* Try to lock the file. */
84 if (flock (utmp_data
->ut_fd
, LOCK_EX
| LOCK_NB
) < 0 && errno
!= ENOSYS
)
86 /* Oh, oh. The file is already locked. Wait a bit and try again. */
89 /* This time we ignore the error. */
90 (void) flock (utmp_data
->ut_fd
, LOCK_EX
| LOCK_NB
);
93 /* Find out how large the file is. */
94 result
= fstat (utmp_data
->ut_fd
, &st
);
97 /* Position file correctly. */
98 if (utmp_data
->loc_utmp
< (off_t
) sizeof (struct utmp
)
99 || utmp_data
->loc_utmp
- sizeof (struct utmp
) > st
.st_size
)
100 /* Not located at any valid entry. Add at the end. */
102 result
= lseek (utmp_data
->ut_fd
, 0L, SEEK_END
);
104 /* Where we'll be if the write succeeds. */
105 utmp_data
->loc_utmp
= st
.st_size
+ sizeof (struct utmp
);
109 lseek (utmp_data
->ut_fd
, utmp_data
->loc_utmp
- sizeof (struct utmp
),
113 /* Write the new data. */
114 if (write (utmp_data
->ut_fd
, id
, sizeof (struct utmp
))
115 != sizeof (struct utmp
))
117 /* If we appended a new record this is only partially written.
119 if (utmp_data
->loc_utmp
> st
.st_size
)
121 (void) ftruncate (utmp_data
->ut_fd
, st
.st_size
);
122 utmp_data
->loc_utmp
= st
.st_size
;
128 /* And unlock the file. */
129 (void) flock (utmp_data
->ut_fd
, LOCK_UN
);
133 weak_alias (__pututline_r
, pututline_r
)