static int
ketama_roller( ketama_continuum* contptr, char* filename, int roller_flag )
{
key_t key;
continuum_resource resource;
// if we have a string like "key:0x1234" that means we want to set up the infastructure
// but leave continuum creation until we manually add servers with ketama_add_server
char cont_filename[PATH_MAX];
time_t fmodtime;
snprintf(cont_filename, sizeof(cont_filename), "%s", filename);
key = get_key(cont_filename, &fmodtime);
if ( key == -1 ) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_roll failed to make a valid key from %s.\n", filename );
syslog1( LOG_INFO, k_error );
return 0;
}
// try to find an existsing resource with a shared memory segment in the array of tracked resources, or create a new attachment resource
if ( !get_shm_resource(key, &resource) ) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_roller failed to get a valid resource.\n" );
syslog1( LOG_INFO, k_error );
return 0;
}
// if the continuum is not stale or new, end here and track the resource if we somehow missed tracking it
if ( (resource.data->fmodtime == fmodtime) && (resource.data->cont_version != 0) ) {
**contptr = resource;
track_shm_resource(resource);
syslog( LOG_DEBUG, "Ketama: ketama_roll() successfully found a valid shared memory segment at %p with ID: %lu and key: %lu, stored into %p.\n",
resource.data, (long unsigned int) resource.shmid, (long unsigned int) resource.key, *contptr);
return 1;
}
// detach from the shared memory segment so that we can attach again in ketama_create to initialize the continuum
if ( ketama_shmdt(resource.data) == -1 ) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_roll failed to detatch from shared memory with errno: %d.\n", errno );
syslog1( LOG_INFO, k_error );
}
// if we've already attempted to run ketama_create then that subroutine failed and we want to fail out
if ( roller_flag != 0) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_create_continuum failed to create a valid continuum.\n" );
syslog1( LOG_INFO, k_error );
return 0;
}
// attempt to run ketama_create continuum
if ( !ketama_create_continuum( key, filename, contptr ) ) {
snprintf( k_error, sizeof(k_error), "Ketama: ketama_create_continuum failed!\n" );
syslog1( LOG_INFO, k_error );
return 0;
}
// if we reach this point then we've created the continuum and reran ketama_roll to check its validity, so just log this and exit
syslog1( LOG_INFO, "Ketama: ketama_create_continuum successfully finished.\n" );
return 1;
}
int
ketama_roll( ketama_continuum* contptr, char* filename )
{
strcpy( k_error, "" );
key_t key;
int shmid;
int *data;
int sem_set_id;
// setlogmask( LOG_UPTO ( LOG_NOTICE | LOG_ERR | LOG_INFO ) );
// openlog( "ketama", LOG_CONS | LOG_PID | LOG_NDELAY, LOG_LOCAL1 );
key = ftok( filename, 'R' );
if ( key == -1 )
{
sprintf( k_error, "Invalid filename specified: %s", filename );
return 0;
}
*contptr = malloc( sizeof( continuum ) );
(*contptr)->numpoints = 0;
(*contptr)->array = 0;
(*contptr)->modtime = 0;
sem_set_id = ketama_sem_init( key );
int sanity = 0;
while ( semctl( sem_set_id, 0, GETVAL, 0 ) == 2 )
{
// wait for the continuum creator to finish, but don't block others
usleep( 5 );
// if we are waiting for > 1 second, take drastic action:
if(++sanity > 1000000)
{
usleep( rand()%50000 );
ketama_sem_unlock( sem_set_id );
break;
}
}
time_t modtime = file_modtime( filename );
time_t* fmodtime = 0;
while ( !fmodtime || modtime != *fmodtime )
{
shmid = shmget( key, MC_SHMSIZE, 0 ); // read only attempt.
data = shmat( shmid, (void *)0, SHM_RDONLY );
if ( data == (void *)(-1) || (*contptr)->modtime != 0 )
{
ketama_sem_lock( sem_set_id );
// if ( (*contptr)->modtime == 0 )
// syslog( LOG_INFO, "Shared memory empty, creating and populating...\n" );
// else
// syslog( LOG_INFO, "Server definitions changed, reloading...\n" );
if ( !ketama_create_continuum( key, filename ) )
{
// strcpy( k_error, "Ketama_create_continuum() failed!" );
ketama_sem_unlock( sem_set_id );
return 0;
}
/* else
syslog( LOG_INFO, "ketama_create_continuum() successfully finished.\n" );*/
shmid = shmget( key, MC_SHMSIZE, 0 ); // read only attempt.
data = shmat( shmid, (void *)0, SHM_RDONLY );
ketama_sem_unlock( sem_set_id );
}
if ( data == (void *)(-1) )
{
strcpy( k_error, "Failed miserably to get pointer to shmemdata!" );
return 0;
}
(*contptr)->numpoints = *data;
(*contptr)->modtime = ++data;
(*contptr)->array = data + sizeof( void* );
fmodtime = (time_t*)( (*contptr)->modtime );
}
return 1;
}
