summaryrefslogtreecommitdiff
path: root/lib/tdb2/test/run-locktimeout.c
blob: 44ae7d57e71af760328fa380eb327a3fd54b11c7 (plain)
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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
#include "tdb2-source.h"
#include <ccan/tap/tap.h>
#include "logging.h"
#include "external-agent.h"

#undef alarm
#define alarm fast_alarm

/* Speed things up by doing things in milliseconds. */
static unsigned int fast_alarm(unsigned int milli_seconds)
{
	struct itimerval it;

	it.it_interval.tv_sec = it.it_interval.tv_usec = 0;
	it.it_value.tv_sec = milli_seconds / 1000;
	it.it_value.tv_usec = milli_seconds * 1000;
	setitimer(ITIMER_REAL, &it, NULL);
	return 0;
}

#define CatchSignal(sig, handler) signal((sig), (handler))

static void do_nothing(int signum)
{
}

/* This example code is taken from SAMBA, so try not to change it. */
static struct flock flock_struct;

/* Return a value which is none of v1, v2 or v3. */
static inline short int invalid_value(short int v1, short int v2, short int v3)
{
	short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
	while (try == v1 || try == v2 || try == v3)
		try++;
	return try;
}

/* We invalidate in as many ways as we can, so the OS rejects it */
static void invalidate_flock_struct(int signum)
{
	flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
	flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
	flock_struct.l_start = -1;
	/* A large negative. */
	flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
}

static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
			void *_timeout)
{
	int ret, saved_errno = errno;
	unsigned int timeout = *(unsigned int *)_timeout;

	flock_struct.l_type = rw;
	flock_struct.l_whence = SEEK_SET;
	flock_struct.l_start = off;
	flock_struct.l_len = len;

	CatchSignal(SIGALRM, invalidate_flock_struct);
	alarm(timeout);

	for (;;) {
		if (waitflag)
			ret = fcntl(fd, F_SETLKW, &flock_struct);
		else
			ret = fcntl(fd, F_SETLK, &flock_struct);

		if (ret == 0)
			break;

		/* Not signalled?  Something else went wrong. */
		if (flock_struct.l_len == len) {
			if (errno == EAGAIN || errno == EINTR)
				continue;
			saved_errno = errno;
			break;
		} else {
			saved_errno = EINTR;
			break;
		}
	}

	alarm(0);
	errno = saved_errno;
	return ret;
}

static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
					       TDB_DATA key,
					       unsigned int timeout,
					       int rw_type)
{
	union tdb_attribute locking;
	enum TDB_ERROR ecode;

	if (timeout) {
		locking.base.attr = TDB_ATTRIBUTE_FLOCK;
		ecode = tdb_get_attribute(tdb, &locking);
		if (ecode != TDB_SUCCESS)
			return ecode;

		/* Replace locking function with our own. */
		locking.flock.data = &timeout;
		locking.flock.lock = timeout_lock;

		ecode = tdb_set_attribute(tdb, &locking);
		if (ecode != TDB_SUCCESS)
			return ecode;
	}
	if (rw_type == F_RDLCK)
		ecode = tdb_chainlock_read(tdb, key);
	else
		ecode = tdb_chainlock(tdb, key);

	if (timeout) {
		tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
	}
	return ecode;
}

int main(int argc, char *argv[])
{
	unsigned int i;
	struct tdb_context *tdb;
	TDB_DATA key = tdb_mkdata("hello", 5);
	int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
			TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT };
	struct agent *agent;

	plan_tests(sizeof(flags) / sizeof(flags[0]) * 15);

	agent = prepare_external_agent();

	for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
		enum TDB_ERROR ecode;
		tdb = tdb_open("run-locktimeout.tdb", flags[i],
			       O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
		if (!ok1(tdb))
			break;

		/* Simple cases: should succeed. */
		ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
							    F_RDLCK);
		ok1(ecode == TDB_SUCCESS);
		ok1(tap_log_messages == 0);

		tdb_chainunlock_read(tdb, key);
		ok1(tap_log_messages == 0);

		ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
							    F_WRLCK);
		ok1(ecode == TDB_SUCCESS);
		ok1(tap_log_messages == 0);

		tdb_chainunlock(tdb, key);
		ok1(tap_log_messages == 0);

		/* OK, get agent to start transaction, then we should time out. */
		ok1(external_agent_operation(agent, OPEN, "run-locktimeout.tdb")
		    == SUCCESS);
		ok1(external_agent_operation(agent, TRANSACTION_START, "")
		    == SUCCESS);
		ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
							    F_WRLCK);
		ok1(ecode == TDB_ERR_LOCK);
		ok1(tap_log_messages == 0);

		/* Even if we get a different signal, should be fine. */
		CatchSignal(SIGUSR1, do_nothing);
		external_agent_operation(agent, SEND_SIGNAL, "");
		ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
							    F_WRLCK);
		ok1(ecode == TDB_ERR_LOCK);
		ok1(tap_log_messages == 0);

		ok1(external_agent_operation(agent, TRANSACTION_COMMIT, "")
		    == SUCCESS);
		ok1(external_agent_operation(agent, CLOSE, "")
		    == SUCCESS);
		tdb_close(tdb);
	}
	free_external_agent(agent);
	return exit_status();
}