1 /* $NetBSD: flock.c,v 1.2 2017/01/28 21:31:50 christos Exp $ */
2
3 /*
4 * Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <config.h>
37
38 #ifndef HAVE_FLOCK
39
40 #include <krb5/roken.h>
41
42 #define OP_MASK (LOCK_SH | LOCK_EX | LOCK_UN)
43
44
45 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
rk_flock(int fd,int operation)46 rk_flock(int fd, int operation)
47 {
48 #if defined(HAVE_FCNTL) && defined(F_SETLK)
49 struct flock arg;
50 int code, cmd;
51
52 arg.l_whence = SEEK_SET;
53 arg.l_start = 0;
54 arg.l_len = 0; /* means to EOF */
55
56 if (operation & LOCK_NB)
57 cmd = F_SETLK;
58 else
59 cmd = F_SETLKW; /* Blocking */
60
61 switch (operation & OP_MASK) {
62 case LOCK_UN:
63 arg.l_type = F_UNLCK;
64 code = fcntl(fd, F_SETLK, &arg);
65 break;
66 case LOCK_SH:
67 arg.l_type = F_RDLCK;
68 code = fcntl(fd, cmd, &arg);
69 break;
70 case LOCK_EX:
71 arg.l_type = F_WRLCK;
72 code = fcntl(fd, cmd, &arg);
73 break;
74 default:
75 errno = EINVAL;
76 code = -1;
77 break;
78 }
79 return code;
80
81 #elif defined(_WIN32)
82 /* Windows */
83
84 #define FLOCK_OFFSET_LOW 0
85 #define FLOCK_OFFSET_HIGH 0
86 #define FLOCK_LENGTH_LOW 0x00000000
87 #define FLOCK_LENGTH_HIGH 0x80000000
88
89 HANDLE hFile;
90 OVERLAPPED ov;
91 BOOL rv = FALSE;
92 DWORD f = 0;
93
94 hFile = (HANDLE) _get_osfhandle(fd);
95 if (hFile == NULL || hFile == INVALID_HANDLE_VALUE) {
96 _set_errno(EBADF);
97 return -1;
98 }
99
100 ZeroMemory(&ov, sizeof(ov));
101 ov.hEvent = NULL;
102 ov.Offset = FLOCK_OFFSET_LOW;
103 ov.OffsetHigh = FLOCK_OFFSET_HIGH;
104
105 if (operation & LOCK_NB)
106 f = LOCKFILE_FAIL_IMMEDIATELY;
107
108 switch (operation & OP_MASK) {
109 case LOCK_UN: /* Unlock */
110 rv = UnlockFileEx(hFile, 0,
111 FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH, &ov);
112 break;
113
114 case LOCK_SH: /* Shared lock */
115 rv = LockFileEx(hFile, f, 0,
116 FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH, &ov);
117 break;
118
119 case LOCK_EX: /* Exclusive lock */
120 rv = LockFileEx(hFile, f|LOCKFILE_EXCLUSIVE_LOCK, 0,
121 FLOCK_LENGTH_LOW, FLOCK_LENGTH_HIGH,
122 &ov);
123 break;
124
125 default:
126 _set_errno(EINVAL);
127 return -1;
128 }
129
130 if (!rv) {
131 switch (GetLastError()) {
132 case ERROR_SHARING_VIOLATION:
133 case ERROR_LOCK_VIOLATION:
134 case ERROR_IO_PENDING:
135 _set_errno(EWOULDBLOCK);
136 break;
137
138 case ERROR_ACCESS_DENIED:
139 _set_errno(EACCES);
140 break;
141
142 default:
143 _set_errno(ENOLCK);
144 }
145 return -1;
146 }
147
148 return 0;
149
150 #else
151 return -1;
152 #endif
153 }
154
155 #endif
156
157