2 * Copyright (c) 2017, De Rais <derais@cock.li>
4 * Permission to use, copy, modify, and/or distribute this software for
5 * any purpose with or without fee is hereby granted, provided that the
6 * above copyright notice and this permission notice appear in all
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
10 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
11 * WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
12 * AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
13 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
14 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
15 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
16 * PERFORMANCE OF THIS SOFTWARE.
30 static int *lock_table
= 0;
31 static size_t lock_table_len
= 0;
34 * Set up the lock files and make sure we can connect to them.
38 * - setup_locks() was not invoked more recently than clean_locks().
40 * Postconditions (success):
42 * - Any other function in this file may be safely called.
44 int setup_locks(const struct configuration
*conf
)
54 if (!(lock_table
= calloc(conf
->boards_num
, sizeof *lock_table
))) {
55 PERROR_MESSAGE("malloc");
56 ERROR_MESSAGE("Cannot set up locks");
60 for (size_t j
= 0; j
< conf
->boards_num
; ++j
) {
64 for (size_t j
= 0; j
< conf
->boards_num
; ++j
) {
65 len
= snprintf(0, 0, "%s/lock_board_%s", conf
->work_path
,
66 conf
->boards
[j
].name
);
69 ERROR_MESSAGE("overflow");
73 if (!(path
= malloc(len
+ 1))) {
74 PERROR_MESSAGE("malloc");
78 sprintf(path
, "%s/lock_board_%s", conf
->work_path
,
79 conf
->boards
[j
].name
);
81 if (!(lock_table
[j
] = open(path
, O_RDWR
| O_CREAT
, 0700))) {
82 PERROR_MESSAGE("open");
83 ERROR_MESSAGE("Cannot open or create lock file %s",
93 lock_table_len
= conf
->boards_num
;
101 * Get a lock for a board
105 * - board_idx represents a board.
107 * - The lock for board_idx is not held in this program.
109 * Postconditions (success):
111 * - The lock for board_idx is now held by this program.
113 int lock_acquire(size_t board_idx
)
118 lock_table
[board_idx
] < 0) {
119 ERROR_MESSAGE("lock_table isn't set up yet");
123 if (lockf(lock_table
[board_idx
], F_LOCK
, 0) < 0) {
124 PERROR_MESSAGE("lockf");
125 ERROR_MESSAGE("Cannot lock board %zu", board_idx
);
136 * Release a lock for a board
140 * - board_idx represents a board.
142 * - The lock for board_idx is held in this program.
144 * Postconditions (success):
146 * - The lock for board_idx is now not held by this program.
148 int lock_release(size_t board_idx
)
151 lock_table
[board_idx
] < 0) {
155 if (lockf(lock_table
[board_idx
], F_ULOCK
, 0) < 0) {
156 PERROR_MESSAGE("lockf");
157 ERROR_MESSAGE("Cannot release lock for board %zu", board_idx
);
166 * Clean up any memory from this file
168 * Postconditions (success):
170 * - Valgrind won't report any memory leaks from this file.
172 * - setup_locks() can be safely called again.
174 int clean_locks(void)
180 for (size_t j
= 0; j
< lock_table_len
; ++j
) {
182 close(lock_table
[j
]);