fis-gtm/sr_unix/db_ipcs_reset.c

200 lines
7.2 KiB
C

/****************************************************************
* *
* Copyright 2001, 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 <sys/mman.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <errno.h>
#include "gtm_unistd.h"
#include "gtm_string.h"
#include "gdsroot.h"
#include "gtm_facility.h"
#include "fileinfo.h"
#include "gdsbt.h"
#include "gdsblk.h"
#include "gtmio.h"
#include "gdsfhead.h"
#include "filestruct.h"
#include "io.h"
#include "iosp.h"
#include "eintr_wrappers.h"
#include "gtmsecshr.h"
#include "secshr_client.h"
#include "mu_rndwn_file.h"
#include "ftok_sems.h"
#include "ipcrmid.h"
#include "gtmmsg.h"
#include "dbfilop.h"
#include "db_ipcs_reset.h"
#include "jnl.h"
#include "do_semop.h"
GBLREF uint4 process_id;
GBLREF ipcs_mesg db_ipcs;
GBLREF gd_region *gv_cur_region;
GBLREF jnl_gbls_t jgbl;
error_def (ERR_TEXT);
error_def (ERR_CRITSEMFAIL);
error_def (ERR_DBFILERR);
error_def (ERR_FILEPARSE);
/* mu_rndwn_file gets a database access control semaphore - this counterpart releases it for one region. This module is invoked
* only by those processes that have previously done the mu_rndwn_file and hence guaranteed to hold the access control semaphore.
* Because of this, we do not ask for ftok semaphore (ftok_sem_lock) as that would cause an out-of-order request
* of locks.
*/
boolean_t db_ipcs_reset(gd_region *reg)
{
int status, semval, save_errno;
uint4 ustatus;
sgmnt_data_ptr_t csd;
file_control *fc;
unix_db_info *udi;
gd_region *temp_region;
char sgmnthdr_unaligned[SGMNT_HDR_LEN + 8], *sgmnthdr_8byte_aligned;
sgmnt_addrs *csa;
assert(reg);
temp_region = gv_cur_region; /* save gv_cur_region wherever there is scope for it to be changed */
gv_cur_region = reg; /* dbfilop needs gv_cur_region */
udi = NULL;
if (NULL != reg->dyn.addr->file_cntl)
udi = FILE_INFO(reg);
if ((NULL == udi) || (INVALID_SEMID == udi->semid))
{
assert(!reg->open);
gv_cur_region = temp_region;
return FALSE;
}
assert(udi->grabbed_access_sem);
csa = &udi->s_addrs;
sgmnthdr_8byte_aligned = &sgmnthdr_unaligned[0];
sgmnthdr_8byte_aligned = (char *)ROUND_UP2((unsigned long)sgmnthdr_8byte_aligned, 8);
csd = (sgmnt_data_ptr_t)&sgmnthdr_8byte_aligned[0];
fc = reg->dyn.addr->file_cntl;
fc->op = FC_OPEN;
status = dbfilop(fc);
gv_cur_region = temp_region;
if (SS_NORMAL != status)
{
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
return FALSE;
}
LSEEKREAD(udi->fd, (off_t)0, csd, SGMNT_HDR_LEN, status);
if (0 != status)
{
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
CLOSEFILE_RESET(udi->fd, status); /* resets "udi->fd" to FD_INVALID */
if (0 != status)
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
return FALSE;
}
assert((udi->semid == csd->semid) || (INVALID_SEMID == csd->semid));
semval = semctl(udi->semid, 1, GETVAL); /* Get the counter semaphore's value */
assert(1 <= semval);
if (1 < semval)
{
assert(jgbl.onlnrlbk); /* everyone else will have total standalone access and hence no one else can be attached */
assert(!reg->read_only); /* ONLINE ROLLBACK must be a read/write process */
if (!reg->read_only)
{
if (0 != (save_errno = do_semop(udi->semid, 1, -1, SEM_UNDO)))
{
gtm_putmsg(VARLSTCNT(8) ERR_CRITSEMFAIL, 2, DB_LEN_STR(reg), ERR_TEXT, 2,
RTS_ERROR_TEXT("db_ipcs_reset - write semaphore release"), save_errno);
return FALSE;
}
assert(1 == (semval = semctl(udi->semid, 0, GETVAL)));
if (0 != (save_errno = do_semop(udi->semid, 0, -1, SEM_UNDO)))
{
gtm_putmsg(VARLSTCNT(8) ERR_CRITSEMFAIL, 2, DB_LEN_STR(reg), ERR_TEXT, 2,
RTS_ERROR_TEXT("db_ipcs_reset - access control semaphore release"), save_errno);
return FALSE;
}
}
/* Since the semval is at least 2, we should NOT remove the semaphore as the other process that still exists
* will encounter an error during its gds_rundown. During the gds_rundown of the other process it will realize
* that it is the only attached process and will take care of we_are_last_writer cases in gds_rundown.
*/
} else
{ /* We are the only one. Remove the semaphore. Logic in db_init knows to handle when the semaphore is removed
* and will retry by creating a new one. But, it is important the semid/shmid fields in the file header is reset
* BEFORE removing the semaphore as otherwise the waiting process in db_init will notice the semaphore removal
* first and will read the file header and can potentially notice the stale semid/shmid values.
*/
if (!reg->read_only)
{
csd->semid = INVALID_SEMID;
csd->shmid = INVALID_SHMID;
csd->gt_sem_ctime.ctime = 0;
csd->gt_shm_ctime.ctime = 0;
LSEEKWRITE(udi->fd, (off_t)0, csd, SGMNT_HDR_LEN, status);
if (0 != status)
{
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
CLOSEFILE_RESET(udi->fd, status); /* resets "udi->fd" to FD_INVALID */
if (0 != status)
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
return FALSE;
}
} else
{
db_ipcs.semid = INVALID_SEMID;
db_ipcs.shmid = INVALID_SHMID;
db_ipcs.gt_sem_ctime = 0;
db_ipcs.gt_shm_ctime = 0;
if (!get_full_path((char *)DB_STR_LEN(reg), db_ipcs.fn, (unsigned int *)&db_ipcs.fn_len,
MAX_TRANS_NAME_LEN, &ustatus))
{
gtm_putmsg(VARLSTCNT(5) ERR_FILEPARSE, 2, DB_LEN_STR(reg), ustatus);
return FALSE;
}
db_ipcs.fn[db_ipcs.fn_len] = 0;
if (0 != (status = send_mesg2gtmsecshr(FLUSH_DB_IPCS_INFO, 0, (char *)NULL, 0)))
{
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
CLOSEFILE_RESET(udi->fd, status); /* resets "udi->fd" to FD_INVALID */
if (0 != status)
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
return FALSE;
}
}
if (0 != sem_rmid(udi->semid))
{
save_errno = errno;
gtm_putmsg(VARLSTCNT(8) ERR_CRITSEMFAIL, 2, DB_LEN_STR(reg), ERR_TEXT, 2,
RTS_ERROR_TEXT("db_ipcs_reset - sem_rmid"), save_errno);
return FALSE;
}
}
udi->grabbed_access_sem = FALSE;
CLOSEFILE_RESET(udi->fd, status); /* resets "udi->fd" to FD_INVALID */
if (0 != status)
gtm_putmsg(VARLSTCNT(5) ERR_DBFILERR, 2, DB_LEN_STR(reg), status);
/* Since we created the ftok semaphore in mu_rndwn_file, we release/remove it now. But, since we are exiting, we
* do not WAIT for the ftok semaphore if we did not get it in one shot (IPC_NOWAIT). The process that holds the
* ftok will eventually release it and so we are guaranteed that when the last process leaves the database, it will
* remove the ftok semaphore as well. This means, not able to lock or release the ftok semaphore is not treated
* as an error condition.
*/
if (ftok_sem_lock(reg, FALSE, TRUE)) /* immediate=TRUE because we don't want to wait while holding access semaphore */
ftok_sem_release(reg, TRUE, TRUE);
udi->semid = INVALID_SEMID;
udi->shmid = INVALID_SHMID;
udi->gt_sem_ctime = 0;
udi->gt_shm_ctime = 0;
return TRUE;
}