git.ozlabs.org Git - ccan/blob - ccan/tdb2/test/run-locktimeout.c

   1 #include <ccan/tdb2/tdb.c>
   2 #include <ccan/tdb2/open.c>
   3 #include <ccan/tdb2/free.c>
   4 #include <ccan/tdb2/lock.c>
   5 #include <ccan/tdb2/io.c>
   6 #include <ccan/tdb2/hash.c>
   7 #include <ccan/tdb2/transaction.c>
   8 #include <ccan/tdb2/check.c>
   9 #include <ccan/tap/tap.h>
  10 #include "logging.h"
  11 #include "external-agent.h"
  12
  13 #undef alarm
  14 #define alarm fast_alarm
  15
  16 /* Speed things up by doing things in milliseconds. */
  17 static unsigned int fast_alarm(unsigned int milli_seconds)
  18 {
  19         struct itimerval it;
  20
  21         it.it_interval.tv_sec = it.it_interval.tv_usec = 0;
  22         it.it_value.tv_sec = milli_seconds / 1000;
  23         it.it_value.tv_usec = milli_seconds * 1000;
  24         setitimer(ITIMER_REAL, &it, NULL);
  25         return 0;
  26 }
  27
  28 #define CatchSignal(sig, handler) signal((sig), (handler))
  29
  30 static void do_nothing(int signum)
  31 {
  32 }
  33
  34 /* This example code is taken from SAMBA, so try not to change it. */
  35 static struct flock flock_struct;
  36
  37 /* Return a value which is none of v1, v2 or v3. */
  38 static inline short int invalid_value(short int v1, short int v2, short int v3)
  39 {
  40         short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
  41         while (try == v1 || try == v2 || try == v3)
  42                 try++;
  43         return try;
  44 }
  45
  46 /* We invalidate in as many ways as we can, so the OS rejects it */
  47 static void invalidate_flock_struct(int signum)
  48 {
  49         flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
  50         flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
  51         flock_struct.l_start = -1;
  52         /* A large negative. */
  53         flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
  54 }
  55
  56 static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
  57                         void *_timeout)
  58 {
  59         int ret, saved_errno = errno;
  60         unsigned int timeout = *(unsigned int *)_timeout;
  61
  62         flock_struct.l_type = rw;
  63         flock_struct.l_whence = SEEK_SET;
  64         flock_struct.l_start = off;
  65         flock_struct.l_len = len;
  66
  67         CatchSignal(SIGALRM, invalidate_flock_struct);
  68         alarm(timeout);
  69
  70         for (;;) {
  71                 if (waitflag)
  72                         ret = fcntl(fd, F_SETLKW, &flock_struct);
  73                 else
  74                         ret = fcntl(fd, F_SETLK, &flock_struct);
  75
  76                 if (ret == 0)
  77                         break;
  78
  79                 /* Not signalled?  Something else went wrong. */
  80                 if (flock_struct.l_len == len) {
  81                         if (errno == EAGAIN || errno == EINTR)
  82                                 continue;
  83                         saved_errno = errno;
  84                         break;
  85                 } else {
  86                         saved_errno = EINTR;
  87                         break;
  88                 }
  89         }
  90
  91         alarm(0);
  92         errno = saved_errno;
  93         return ret;
  94 }
  95
  96 static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
  97                                                TDB_DATA key,
  98                                                unsigned int timeout,
  99                                                int rw_type)
 100 {
 101         union tdb_attribute locking;
 102         enum TDB_ERROR ecode;
 103
 104         if (timeout) {
 105                 locking.base.attr = TDB_ATTRIBUTE_FLOCK;
 106                 ecode = tdb_get_attribute(tdb, &locking);
 107                 if (ecode != TDB_SUCCESS)
 108                         return ecode;
 109
 110                 /* Replace locking function with our own. */
 111                 locking.flock.data = &timeout;
 112                 locking.flock.lock = timeout_lock;
 113
 114                 ecode = tdb_set_attribute(tdb, &locking);
 115                 if (ecode != TDB_SUCCESS)
 116                         return ecode;
 117         }
 118         if (rw_type == F_RDLCK)
 119                 ecode = tdb_chainlock_read(tdb, key);
 120         else
 121                 ecode = tdb_chainlock(tdb, key);
 122
 123         if (timeout) {
 124                 tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
 125         }
 126         return ecode;
 127 }
 128
 129 int main(int argc, char *argv[])
 130 {
 131         unsigned int i;
 132         struct tdb_context *tdb;
 133         TDB_DATA key = tdb_mkdata("hello", 5);
 134         int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
 135                         TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT };
 136         struct agent *agent;
 137
 138         plan_tests(sizeof(flags) / sizeof(flags[0]) * 15);
 139
 140         agent = prepare_external_agent();
 141
 142         for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
 143                 enum TDB_ERROR ecode;
 144                 tdb = tdb_open("run-locktimeout.tdb", flags[i],
 145                                O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
 146                 if (!ok1(tdb))
 147                         break;
 148
 149                 /* Simple cases: should succeed. */
 150                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 151                                                             F_RDLCK);
 152                 ok1(ecode == TDB_SUCCESS);
 153                 ok1(tap_log_messages == 0);
 154
 155                 tdb_chainunlock_read(tdb, key);
 156                 ok1(tap_log_messages == 0);
 157
 158                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 159                                                             F_WRLCK);
 160                 ok1(ecode == TDB_SUCCESS);
 161                 ok1(tap_log_messages == 0);
 162
 163                 tdb_chainunlock(tdb, key);
 164                 ok1(tap_log_messages == 0);
 165
 166                 /* OK, get agent to start transaction, then we should time out. */
 167                 ok1(external_agent_operation(agent, OPEN, "run-locktimeout.tdb")
 168                     == SUCCESS);
 169                 ok1(external_agent_operation(agent, TRANSACTION_START, "")
 170                     == SUCCESS);
 171                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 172                                                             F_WRLCK);
 173                 ok1(ecode == TDB_ERR_LOCK);
 174                 ok1(tap_log_messages == 0);
 175
 176                 /* Even if we get a different signal, should be fine. */
 177                 CatchSignal(SIGUSR1, do_nothing);
 178                 external_agent_operation(agent, SEND_SIGNAL, "");
 179                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 180                                                             F_WRLCK);
 181                 ok1(ecode == TDB_ERR_LOCK);
 182                 ok1(tap_log_messages == 0);
 183
 184                 ok1(external_agent_operation(agent, TRANSACTION_COMMIT, "")
 185                     == SUCCESS);
 186                 ok1(external_agent_operation(agent, CLOSE, "")
 187                     == SUCCESS);
 188                 tdb_close(tdb);
 189         }
 190         free_external_agent(agent);
 191         return exit_status();
 192 }