lib/tdb2/test/api-locktimeout.c

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