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fis-gtm/sr_unix/gtm_semutils.c

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/****************************************************************
* *
* Copyright 2011, 2012 Fidelity Information Services, Inc *
* *
* This source code contains the intellectual property *
* of its copyright holder(s), and is made available *
* under a license. If you do not know the terms of *
* the license, please stop and do not read further. *
* *
****************************************************************/
#include "mdef.h"
#include "gtm_ipc.h"
#include "gtm_unistd.h"
#include "gtm_string.h"
#include "gtm_stdlib.h"
#include "gtm_fcntl.h"
#include "gtm_stdio.h"
#include "gtm_stat.h"
#include "iosp.h"
#include <sys/mman.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/time.h>
#include <errno.h>
#include <signal.h> /* for kill(), SIGTERM, SIGQUIT */
#include "gdsroot.h"
#include "gdsbt.h"
#include "gdsfhead.h"
#include "eintr_wrapper_semop.h"
#include "gtm_sem.h"
#include "gtm_c_stack_trace.h"
#include "gtm_semutils.h"
#include "gtmimagename.h"
#include "do_semop.h"
GBLREF uint4 process_id;
GBLREF volatile uint4 heartbeat_counter;
error_def(ERR_CRITSEMFAIL);
error_def(ERR_SEMWT2LONG);
error_def(ERR_RESRCWAIT);
error_def(ERR_RESRCINTRLCKBYPAS);
error_def(ERR_TEXT);
#define FULLTIME(MAX_HRTBT_DELTA, START_HRTBT_CNTR) (MAX_HRTBT_DELTA - 1 == (heartbeat_counter - START_HRTBT_CNTR))
#define HALFTIME(MAX_HRTBT_DELTA, START_HRTBT_CNTR) (MAX_HRTBT_DELTA / 2 == (heartbeat_counter - START_HRTBT_CNTR))
#define STACKTRACE_TIME(MAX_HRTBT_DELTA, START_HRTBT_CNTR) (HALFTIME(MAX_HRTBT_DELTA, START_HRTBT_CNTR) || \
FULLTIME(MAX_HRTBT_DELTA, START_HRTBT_CNTR))
#define USER_SPECIFIED_TIME_EXPIRED(MAX_HRTBT_DELTA, START_HRTBT_CNTR) (MAX_HRTBT_DELTA <= (heartbeat_counter - START_HRTBT_CNTR))
#define IS_ACCESS_SEM (gtm_access_sem == semtype)
#define IS_FTOK_SEM (gtm_ftok_sem == semtype)
boolean_t do_blocking_semop(int semid, enum gtm_semtype semtype, uint4 start_hrtbt_cntr,
semwait_status_t *retstat, gd_region *reg, boolean_t *bypass)
{
boolean_t need_stacktrace, indefinite_wait;
char *msgstr;
int status = SS_NORMAL, save_errno, sem_pid, semval, i, sopcnt;
uint4 loopcnt = 0, max_hrtbt_delta, lcl_hrtbt_cntr, stuck_cnt = 0;
boolean_t stacktrace_issued = FALSE, is_editor; /* This is LKE or DSE editor image */
struct sembuf sop[3];
char *sem_names[2] = {"FTOK", "access control"}; /* based on gtm_semtype enum order */
DCL_THREADGBL_ACCESS;
SETUP_THREADGBL_ACCESS;
assert(IS_FTOK_SEM || IS_ACCESS_SEM);
/* Access control semaphore should not be increased when the process is readonly */
SET_GTM_SOP_ARRAY(sop, sopcnt, IS_FTOK_SEM || !reg->read_only, (SEM_UNDO | IPC_NOWAIT));
is_editor = (IS_DSE_IMAGE || IS_LKE_IMAGE);
max_hrtbt_delta = TREF(dbinit_max_hrtbt_delta);
assert(NO_SEMWAIT_ON_EAGAIN != max_hrtbt_delta);
if (indefinite_wait = (INDEFINITE_WAIT_ON_EAGAIN == max_hrtbt_delta))
max_hrtbt_delta = DEFAULT_DBINIT_MAX_HRTBT_DELTA;
need_stacktrace = (DEFAULT_DBINIT_MAX_HRTBT_DELTA <= max_hrtbt_delta) && !is_editor;
if (!need_stacktrace)
{ /* Since the user specified wait time is less than the default wait, wait that time without any stack trace */
if (is_editor)
{ /* Editors are able to bypass after 3 seconds of wait. IPC_NOWAIT smeop every second.
* The semaphore value must be at least 2 to make sure the shared memeory is already created.
*/
if (-1 == (semval = semctl(semid, 1, GETVAL))) /* semval = number of process attached */
RETURN_SEMWAIT_FAILURE(retstat, errno, op_semctl, ERR_CRITSEMFAIL, 0, 0);
if (semval > 1)
{
if (-1 == (sem_pid = semctl(semid, 0, GETPID)))
RETURN_SEMWAIT_FAILURE(retstat, errno, op_semctl, ERR_CRITSEMFAIL, 0, 0);
gtm_putmsg(VARLSTCNT(10) ERR_RESRCWAIT, 8, LEN_AND_STR(sem_names[semtype]), REG_LEN_STR(reg),
DB_LEN_STR(reg), sem_pid, semid);
i = 0;
do
{
SEMOP(semid, sop, sopcnt, status, NO_WAIT);
save_errno = errno;
LONG_SLEEP(1);
i++;
} while ((-1 == status) && (EAGAIN == save_errno) && (i < MAX_BYPASS_WAIT_SEC));
if (-1 != status)
return TRUE;
assert(EINTR != save_errno);
if (EAGAIN == save_errno)
{
*bypass = TRUE;
save_errno = 0;
send_msg(VARLSTCNT(12) ERR_RESRCINTRLCKBYPAS, 10,
LEN_AND_STR((IS_LKE_IMAGE ? "LKE" : "DSE")), process_id,
LEN_AND_STR(sem_names[semtype]), REG_LEN_STR(reg), DB_LEN_STR(reg), sem_pid);
/* If this is a readonly access, we don't increment access semaphore's counter. See
* SET_GTM_SOP_ARRAY definition in gtm_semutils.h and how it is called from db_init().
*/
if (IS_FTOK_SEM || !reg->read_only)
{
/* Increase the counter semaphore. */
save_errno = do_semop(semid, 1, 1, SEM_UNDO);
if (save_errno == 0)
return TRUE;
*bypass = FALSE; /* Semaphore removed when attempting to bypass. Abort bypass. */
} else
return TRUE;
}
}
}
if (!is_editor || (semval < 2))
{
/* Do not bypass. (We are not LKE/DSE OR) OR (There are less than 2 processes inside) */
sop[0].sem_flg = sop[1].sem_flg = sop[2].sem_flg = SEM_UNDO; /* Enable blocking wait. */
do
{
status = semop(semid, sop, sopcnt);
save_errno = errno;
} while ((-1 == status) && (EINTR == errno) && !USER_SPECIFIED_TIME_EXPIRED(max_hrtbt_delta,
start_hrtbt_cntr));
if (-1 != status)
return TRUE;
/* someone else is holding it and we are done waiting */
sem_pid = semctl(semid, 0, GETPID);
if (-1 != sem_pid)
RETURN_SEMWAIT_FAILURE(retstat, 0, op_invalid_sem_syscall, ERR_SEMWT2LONG, 0, sem_pid);
}
} else
{
sop[0].sem_flg = sop[1].sem_flg = sop[2].sem_flg = SEM_UNDO; /* Enable blocking wait. */
lcl_hrtbt_cntr = heartbeat_counter;
while (!USER_SPECIFIED_TIME_EXPIRED(max_hrtbt_delta, start_hrtbt_cntr))
{
loopcnt++;
status = semop(semid, sop, sopcnt);
if (-1 != status)
{
SENDMSG_SEMOP_SUCCESS_IF_NEEDED(stacktrace_issued, semtype);
return TRUE;
}
save_errno = errno;
if (EINTR != save_errno)
break;
if (lcl_hrtbt_cntr != heartbeat_counter)
{ /* We waited for at least one heartbeat. This is to ensure that we don't prematurely conclude
* that we waited enough for the semop to return before taking a stack trace of the holding
* process.
*/
sem_pid = semctl(semid, 0, GETPID);
if (-1 != sem_pid)
{
if (STACKTRACE_TIME(max_hrtbt_delta, start_hrtbt_cntr))
{ /* We want to take the stack trace at half-time and after the wait. But, since
* the loop will continue ONLY as long as the specified wait time has not yet
* elapsed, get the stack trace at half-time and at the penultimate heartbeat.
*/
stuck_cnt++;
if (IS_FTOK_SEM)
msgstr = (1 == stuck_cnt) ? "SEMWT2LONG_FTOK_INFO" : "SEMWT2LONG_FTOK";
else
msgstr = (1 == stuck_cnt) ? "SEMWT2LONG_ACCSEM_INFO" : "SEMWT2LONG_ACCSEM";
if ((0 != sem_pid) && (sem_pid != process_id))
{
GET_C_STACK_FROM_SCRIPT(msgstr, process_id, sem_pid, stuck_cnt);
if (TREF(gtm_environment_init))
stacktrace_issued = TRUE;
}
}
lcl_hrtbt_cntr = heartbeat_counter;
continue;
}
save_errno = errno; /* for the failed semctl, fall-through */
break;
}
}
if ((0 == loopcnt) || (EINTR == save_errno))
{ /* the timer has expired */
if (!indefinite_wait && !TREF(gtm_environment_init))
RETURN_SEMWAIT_FAILURE(retstat, 0, op_invalid_sem_syscall, ERR_SEMWT2LONG, 0, sem_pid);
SEMOP(semid, sop, sopcnt, status, NO_WAIT); /* ignore EINTR if asked for indefinite wait or run in-house */
if (-1 != status)
{
SENDMSG_SEMOP_SUCCESS_IF_NEEDED(stacktrace_issued, semtype);
return TRUE;
}
save_errno = errno;
if (TREF(gtm_environment_init) && SEM_REMOVED(save_errno))
{ /* If the semaphore is removed (possible by a concurrent gds_rundown), the caller will retry
* by doing semget once again. In most cases this will succeed and the process will get hold
* of the semaphore and so the SEM_REMOVED condition can be treated as if the semop succeeded
* So, log a SEMOP success message in the syslog.
*/
SENDMSG_SEMOP_SUCCESS_IF_NEEDED(stacktrace_issued, semtype);
}
/* else some other error occurred; fall-through */
}
/* else some other error occurred; fall-through */
}
assert(0 != save_errno);
RETURN_SEMWAIT_FAILURE(retstat, save_errno, op_semctl_or_semop, ERR_CRITSEMFAIL, 0, 0);
}
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