lib/tdb2/test/api-locktimeout.c

   1 #include "config.h"
   2 #include "tdb2.h"
   3 #include "tap-interface.h"
   4 #include "system/wait.h"
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <sys/time.h>
   8 #include <fcntl.h>
   9 #include <limits.h>
  10 #include <errno.h>
  11 #include "logging.h"
  12 #include "external-agent.h"
  13
  14 #undef alarm
  15 #define alarm fast_alarm
  16
  17 /* Speed things up by doing things in milliseconds. */
  18 static unsigned int fast_alarm(unsigned int milli_seconds)
  19 {
  20         struct itimerval it;
  21
  22         it.it_interval.tv_sec = it.it_interval.tv_usec = 0;
  23         it.it_value.tv_sec = milli_seconds / 1000;
  24         it.it_value.tv_usec = milli_seconds * 1000;
  25         setitimer(ITIMER_REAL, &it, NULL);
  26         return 0;
  27 }
  28
  29 #define CatchSignal(sig, handler) signal((sig), (handler))
  30
  31 static void do_nothing(int signum)
  32 {
  33 }
  34
  35 /* This example code is taken from SAMBA, so try not to change it. */
  36 static struct flock flock_struct;
  37
  38 /* Return a value which is none of v1, v2 or v3. */
  39 static inline short int invalid_value(short int v1, short int v2, short int v3)
  40 {
  41         short int try = (v1+v2+v3)^((v1+v2+v3) << 16);
  42         while (try == v1 || try == v2 || try == v3)
  43                 try++;
  44         return try;
  45 }
  46
  47 /* We invalidate in as many ways as we can, so the OS rejects it */
  48 static void invalidate_flock_struct(int signum)
  49 {
  50         flock_struct.l_type = invalid_value(F_RDLCK, F_WRLCK, F_UNLCK);
  51         flock_struct.l_whence = invalid_value(SEEK_SET, SEEK_CUR, SEEK_END);
  52         flock_struct.l_start = -1;
  53         /* A large negative. */
  54         flock_struct.l_len = (((off_t)1 << (sizeof(off_t)*CHAR_BIT - 1)) + 1);
  55 }
  56
  57 static int timeout_lock(int fd, int rw, off_t off, off_t len, bool waitflag,
  58                         void *_timeout)
  59 {
  60         int ret, saved_errno = errno;
  61         unsigned int timeout = *(unsigned int *)_timeout;
  62
  63         flock_struct.l_type = rw;
  64         flock_struct.l_whence = SEEK_SET;
  65         flock_struct.l_start = off;
  66         flock_struct.l_len = len;
  67
  68         CatchSignal(SIGALRM, invalidate_flock_struct);
  69         alarm(timeout);
  70
  71         for (;;) {
  72                 if (waitflag)
  73                         ret = fcntl(fd, F_SETLKW, &flock_struct);
  74                 else
  75                         ret = fcntl(fd, F_SETLK, &flock_struct);
  76
  77                 if (ret == 0)
  78                         break;
  79
  80                 /* Not signalled?  Something else went wrong. */
  81                 if (flock_struct.l_len == len) {
  82                         if (errno == EAGAIN || errno == EINTR)
  83                                 continue;
  84                         saved_errno = errno;
  85                         break;
  86                 } else {
  87                         saved_errno = EINTR;
  88                         break;
  89                 }
  90         }
  91
  92         alarm(0);
  93         errno = saved_errno;
  94         return ret;
  95 }
  96
  97 static int tdb_chainlock_with_timeout_internal(struct tdb_context *tdb,
  98                                                TDB_DATA key,
  99                                                unsigned int timeout,
 100                                                int rw_type)
 101 {
 102         union tdb_attribute locking;
 103         enum TDB_ERROR ecode;
 104
 105         if (timeout) {
 106                 locking.base.attr = TDB_ATTRIBUTE_FLOCK;
 107                 ecode = tdb_get_attribute(tdb, &locking);
 108                 if (ecode != TDB_SUCCESS)
 109                         return ecode;
 110
 111                 /* Replace locking function with our own. */
 112                 locking.flock.data = &timeout;
 113                 locking.flock.lock = timeout_lock;
 114
 115                 ecode = tdb_set_attribute(tdb, &locking);
 116                 if (ecode != TDB_SUCCESS)
 117                         return ecode;
 118         }
 119         if (rw_type == F_RDLCK)
 120                 ecode = tdb_chainlock_read(tdb, key);
 121         else
 122                 ecode = tdb_chainlock(tdb, key);
 123
 124         if (timeout) {
 125                 tdb_unset_attribute(tdb, TDB_ATTRIBUTE_FLOCK);
 126         }
 127         return ecode;
 128 }
 129
 130 int main(int argc, char *argv[])
 131 {
 132         unsigned int i;
 133         struct tdb_context *tdb;
 134         TDB_DATA key = tdb_mkdata("hello", 5);
 135         int flags[] = { TDB_DEFAULT, TDB_NOMMAP,
 136                         TDB_CONVERT, TDB_NOMMAP|TDB_CONVERT,
 137                         TDB_VERSION1, TDB_NOMMAP|TDB_VERSION1,
 138                         TDB_CONVERT|TDB_VERSION1,
 139                         TDB_NOMMAP|TDB_CONVERT|TDB_VERSION1 };
 140         struct agent *agent;
 141
 142         plan_tests(sizeof(flags) / sizeof(flags[0]) * 15);
 143
 144         agent = prepare_external_agent();
 145
 146         for (i = 0; i < sizeof(flags) / sizeof(flags[0]); i++) {
 147                 enum TDB_ERROR ecode;
 148                 tdb = tdb_open("run-locktimeout.tdb", flags[i],
 149                                O_RDWR|O_CREAT|O_TRUNC, 0600, &tap_log_attr);
 150                 if (!ok1(tdb))
 151                         break;
 152
 153                 /* Simple cases: should succeed. */
 154                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 155                                                             F_RDLCK);
 156                 ok1(ecode == TDB_SUCCESS);
 157                 ok1(tap_log_messages == 0);
 158
 159                 tdb_chainunlock_read(tdb, key);
 160                 ok1(tap_log_messages == 0);
 161
 162                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 163                                                             F_WRLCK);
 164                 ok1(ecode == TDB_SUCCESS);
 165                 ok1(tap_log_messages == 0);
 166
 167                 tdb_chainunlock(tdb, key);
 168                 ok1(tap_log_messages == 0);
 169
 170                 /* OK, get agent to start transaction, then we should time out. */
 171                 ok1(external_agent_operation(agent, OPEN, "run-locktimeout.tdb")
 172                     == SUCCESS);
 173                 ok1(external_agent_operation(agent, TRANSACTION_START, "")
 174                     == SUCCESS);
 175                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 176                                                             F_WRLCK);
 177                 ok1(ecode == TDB_ERR_LOCK);
 178                 ok1(tap_log_messages == 0);
 179
 180                 /* Even if we get a different signal, should be fine. */
 181                 CatchSignal(SIGUSR1, do_nothing);
 182                 external_agent_operation(agent, SEND_SIGNAL, "");
 183                 ecode = tdb_chainlock_with_timeout_internal(tdb, key, 20,
 184                                                             F_WRLCK);
 185                 ok1(ecode == TDB_ERR_LOCK);
 186                 ok1(tap_log_messages == 0);
 187
 188                 ok1(external_agent_operation(agent, TRANSACTION_COMMIT, "")
 189                     == SUCCESS);
 190                 ok1(external_agent_operation(agent, CLOSE, "")
 191                     == SUCCESS);
 192                 tdb_close(tdb);
 193         }
 194         free_external_agent(agent);
 195         return exit_status();
 196 }