1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
/*
* lib/krb5/os/lock_file.c
*
* Copyright 1990, 1998 by the Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*
*
* libos: krb5_lock_file routine
*/
#include "k5-int.h"
#include <stdio.h>
#if !defined(_MSDOS) && !defined(_WIN32) && !defined(HAVE_MACSOCK_H)
/* Unix version... */
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <errno.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if defined(HAVE_FCNTL_H) && defined(F_SETLKW) && defined(F_RDLCK)
#define POSIX_FILE_LOCKS
#endif
#ifdef HAVE_FLOCK
#ifndef sysvimp
#include <sys/file.h>
#endif
#else
#ifndef LOCK_SH
#define LOCK_SH 0
#define LOCK_EX 0
#define LOCK_UN 0
#endif
#endif
/*ARGSUSED*/
krb5_error_code
krb5_lock_file(context, fd, mode)
krb5_context context;
int fd;
int mode;
{
int lock_flag = -1;
krb5_error_code retval = 0;
#ifdef POSIX_FILE_LOCKS
int lock_cmd = F_SETLKW;
static struct flock flock_zero;
struct flock lock_arg;
lock_arg = flock_zero;
#endif
switch (mode & ~KRB5_LOCKMODE_DONTBLOCK) {
case KRB5_LOCKMODE_SHARED:
#ifdef POSIX_FILE_LOCKS
lock_arg.l_type = F_RDLCK;
#endif
lock_flag = LOCK_SH;
break;
case KRB5_LOCKMODE_EXCLUSIVE:
#ifdef POSIX_FILE_LOCKS
lock_arg.l_type = F_WRLCK;
#endif
lock_flag = LOCK_EX;
break;
case KRB5_LOCKMODE_UNLOCK:
#ifdef POSIX_FILE_LOCKS
lock_arg.l_type = F_UNLCK;
#endif
lock_flag = LOCK_UN;
break;
}
if (lock_flag == -1)
return(KRB5_LIBOS_BADLOCKFLAG);
if (mode & KRB5_LOCKMODE_DONTBLOCK) {
#ifdef POSIX_FILE_LOCKS
lock_cmd = F_SETLK;
#endif
#ifdef HAVE_FLOCK
lock_flag |= LOCK_NB;
#endif
}
#ifdef POSIX_FILE_LOCKS
lock_arg.l_whence = 0;
lock_arg.l_start = 0;
lock_arg.l_len = 0;
if (fcntl(fd, lock_cmd, &lock_arg) == -1) {
if (errno == EACCES || errno == EAGAIN) /* see POSIX/IEEE 1003.1-1988,
6.5.2.4 */
return(EAGAIN);
if (errno != EINVAL) /* Fall back to flock if we get EINVAL */
return(errno);
retval = errno;
} else
return 0; /* We succeeded. Yay. */
#endif
#ifdef HAVE_FLOCK
if (flock(fd, lock_flag) == -1)
retval = errno;
#endif
return retval;
}
#else /* MSDOS or Macintosh */
krb5_error_code
krb5_lock_file(context, fd, mode)
krb5_context context;
int fd;
int mode;
{
return 0;
}
#endif
|
