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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996-2002
* Sleepycat Software. All rights reserved.
*/
#include "db_config.h"
#ifndef lint
static const char revid[] = "$Id: env_region.c,v 1.1.1.1 2003/11/20 22:13:20 toshok Exp $";
#endif /* not lint */
#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#endif
#include "db_int.h"
#include "dbinc/db_shash.h"
#include "dbinc/lock.h"
#include "dbinc/log.h"
#include "dbinc/mp.h"
#include "dbinc/rep.h"
#include "dbinc/txn.h"
static int __db_des_destroy __P((DB_ENV *, REGION *));
static int __db_des_get __P((DB_ENV *, REGINFO *, REGINFO *, REGION **));
static int __db_e_remfile __P((DB_ENV *));
static int __db_faultmem __P((DB_ENV *, void *, size_t, int));
static void __db_region_destroy __P((DB_ENV *, REGINFO *));
/*
* __db_e_attach
* Join/create the environment
*
* PUBLIC: int __db_e_attach __P((DB_ENV *, u_int32_t *));
*/
int
__db_e_attach(dbenv, init_flagsp)
DB_ENV *dbenv;
u_int32_t *init_flagsp;
{
REGENV *renv;
REGENV_REF ref;
REGINFO *infop;
REGION *rp, tregion;
size_t size;
size_t nrw;
u_int32_t mbytes, bytes;
int retry_cnt, ret, segid;
char buf[sizeof(DB_REGION_FMT) + 20];
#if !defined(HAVE_MUTEX_THREADS)
/*
* !!!
* If we don't have spinlocks, we need a file descriptor for fcntl(2)
* locking. We use the file handle from the REGENV file for this
* purpose.
*
* Since we may be using shared memory regions, e.g., shmget(2), and
* not a mapped-in regular file, the backing file may be only a few
* bytes in length. So, this depends on the ability to call fcntl to
* lock file offsets much larger than the actual physical file. I
* think that's safe -- besides, very few systems actually need this
* kind of support, SunOS is the only one still in wide use of which
* I'm aware.
*
* The error case is if an application lacks spinlocks and wants to be
* threaded. That doesn't work because fcntl may lock the underlying
* process, including all its threads.
*/
if (F_ISSET(dbenv, DB_ENV_THREAD)) {
__db_err(dbenv,
"architecture lacks fast mutexes: applications cannot be threaded");
return (EINVAL);
}
#endif
/* Initialization */
retry_cnt = 0;
/* Repeated initialization. */
loop: renv = NULL;
/* Set up the DB_ENV's REG_INFO structure. */
if ((ret = __os_calloc(dbenv, 1, sizeof(REGINFO), &infop)) != 0)
return (ret);
infop->type = REGION_TYPE_ENV;
infop->id = REGION_ID_ENV;
infop->mode = dbenv->db_mode;
infop->flags = REGION_JOIN_OK;
if (F_ISSET(dbenv, DB_ENV_CREATE))
F_SET(infop, REGION_CREATE_OK);
/*
* We have to single-thread the creation of the REGENV region. Once
* it exists, we can do locking using locks in the region, but until
* then we have to be the only player in the game.
*
* If this is a private environment, we are only called once and there
* are no possible race conditions.
*
* If this is a public environment, we use the filesystem to ensure
* the creation of the environment file is single-threaded.
*/
if (F_ISSET(dbenv, DB_ENV_PRIVATE)) {
if ((ret = __os_strdup(dbenv,
"process-private", &infop->name)) != 0)
goto err;
goto creation;
}
/* Build the region name. */
(void)snprintf(buf, sizeof(buf), "%s", DB_REGION_ENV);
if ((ret = __db_appname(dbenv,
DB_APP_NONE, buf, 0, NULL, &infop->name)) != 0)
goto err;
/*
* Try to create the file, if we have the authority. We have to ensure
* that multiple threads/processes attempting to simultaneously create
* the file are properly ordered. Open using the O_CREAT and O_EXCL
* flags so that multiple attempts to create the region will return
* failure in all but one. POSIX 1003.1 requires that EEXIST be the
* errno return value -- I sure hope they're right.
*/
if (F_ISSET(dbenv, DB_ENV_CREATE)) {
if ((ret = __os_open(dbenv, infop->name,
DB_OSO_CREATE | DB_OSO_DIRECT | DB_OSO_EXCL | DB_OSO_REGION,
dbenv->db_mode, dbenv->lockfhp)) == 0)
goto creation;
if (ret != EEXIST) {
__db_err(dbenv,
"%s: %s", infop->name, db_strerror(ret));
goto err;
}
}
/*
* If we couldn't create the file, try and open it. (If that fails,
* we're done.)
*/
if ((ret = __os_open(dbenv, infop->name, DB_OSO_REGION | DB_OSO_DIRECT,
dbenv->db_mode, dbenv->lockfhp)) != 0)
goto err;
/*
* !!!
* The region may be in system memory not backed by the filesystem
* (more specifically, not backed by this file), and we're joining
* it. In that case, the process that created it will have written
* out a REGENV_REF structure as its only contents. We read that
* structure before we do anything further, e.g., we can't just map
* that file in and then figure out what's going on.
*
* All of this noise is because some systems don't have a coherent VM
* and buffer cache, and what's worse, when you mix operations on the
* VM and buffer cache, half the time you hang the system.
*
* If the file is the size of an REGENV_REF structure, then we know
* the real region is in some other memory. (The only way you get a
* file that size is to deliberately write it, as it's smaller than
* any possible disk sector created by writing a file or mapping the
* file into memory.) In which case, retrieve the structure from the
* file and use it to acquire the referenced memory.
*
* If the structure is larger than a REGENV_REF structure, then this
* file is backing the shared memory region, and we just map it into
* memory.
*
* And yes, this makes me want to take somebody and kill them. (I
* digress -- but you have no freakin' idea. This is unbelievably
* stupid and gross, and I've probably spent six months of my life,
* now, trying to make different versions of it work.)
*/
if ((ret = __os_ioinfo(dbenv, infop->name,
dbenv->lockfhp, &mbytes, &bytes, NULL)) != 0) {
__db_err(dbenv, "%s: %s", infop->name, db_strerror(ret));
goto err;
}
/*
* !!!
* A size_t is OK -- regions get mapped into memory, and so can't
* be larger than a size_t.
*/
size = mbytes * MEGABYTE + bytes;
/*
* If the size is less than the size of a REGENV_REF structure, the
* region (or, possibly, the REGENV_REF structure) has not yet been
* completely written. Wait awhile and try again.
*
* Otherwise, if the size is the size of a REGENV_REF structure,
* read it into memory and use it as a reference to the real region.
*/
if (size <= sizeof(ref)) {
if (size != sizeof(ref))
goto retry;
if ((ret = __os_read(dbenv, dbenv->lockfhp, &ref,
sizeof(ref), &nrw)) != 0 || nrw < (size_t)sizeof(ref)) {
if (ret == 0)
ret = EIO;
__db_err(dbenv,
"%s: unable to read system-memory information from: %s",
infop->name, db_strerror(ret));
goto err;
}
size = ref.size;
segid = ref.segid;
F_SET(dbenv, DB_ENV_SYSTEM_MEM);
} else if (F_ISSET(dbenv, DB_ENV_SYSTEM_MEM)) {
ret = EINVAL;
__db_err(dbenv,
"%s: existing environment not created in system memory: %s",
infop->name, db_strerror(ret));
goto err;
} else
segid = INVALID_REGION_SEGID;
/*
* If not doing thread locking, we need to save the file handle for
* fcntl(2) locking. Otherwise, discard the handle, we no longer
* need it, and the less contact between the buffer cache and the VM,
* the better.
*/
#ifdef HAVE_MUTEX_THREADS
__os_closehandle(dbenv, dbenv->lockfhp);
#endif
/* Call the region join routine to acquire the region. */
memset(&tregion, 0, sizeof(tregion));
tregion.size = (roff_t)size;
tregion.segid = segid;
if ((ret = __os_r_attach(dbenv, infop, &tregion)) != 0)
goto err;
/*
* The environment's REGENV structure has to live at offset 0 instead
* of the usual shalloc information. Set the primary reference and
* correct the "addr" value to reference the shalloc region. Note,
* this means that all of our offsets (R_ADDR/R_OFFSET) get shifted
* as well, but that should be fine.
*/
infop->primary = R_ADDR(infop, 0);
infop->addr = (u_int8_t *)infop->addr + sizeof(REGENV);
/*
* Check if the environment has had a catastrophic failure.
*
* Check the magic number to ensure the region is initialized. If the
* magic number isn't set, the lock may not have been initialized, and
* an attempt to use it could lead to random behavior.
*
* The panic and magic values aren't protected by any lock, so we never
* use them in any check that's more complex than set/not-set.
*
* !!!
* I'd rather play permissions games using the underlying file, but I
* can't because Windows/NT filesystems won't open files mode 0.
*/
renv = infop->primary;
if (renv->envpanic && !F_ISSET(dbenv, DB_ENV_NOPANIC)) {
ret = __db_panic_msg(dbenv);
goto err;
}
if (renv->magic != DB_REGION_MAGIC)
goto retry;
/* Make sure the region matches our build. */
if (renv->majver != DB_VERSION_MAJOR ||
renv->minver != DB_VERSION_MINOR ||
renv->patch != DB_VERSION_PATCH) {
__db_err(dbenv,
"Program version %d.%d.%d doesn't match environment version %d.%d.%d",
DB_VERSION_MAJOR, DB_VERSION_MINOR, DB_VERSION_PATCH,
renv->majver, renv->minver, renv->patch);
#ifndef DIAGNOSTIC
ret = EINVAL;
goto err;
#endif
}
/* Lock the environment. */
MUTEX_LOCK(dbenv, &renv->mutex);
/*
* Finally! We own the environment now. Repeat the panic check, it's
* possible that it was set while we waited for the lock.
*/
if (renv->envpanic && !F_ISSET(dbenv, DB_ENV_NOPANIC)) {
ret = __db_panic_msg(dbenv);
goto err_unlock;
}
/*
* Get a reference to the underlying REGION information for this
* environment.
*/
if ((ret = __db_des_get(dbenv, infop, infop, &rp)) != 0 || rp == NULL) {
MUTEX_UNLOCK(dbenv, &renv->mutex);
goto find_err;
}
infop->rp = rp;
/*
* There's still a possibility for inconsistent data. When we acquired
* the size of the region and attached to it, it might have still been
* growing as part of its creation. We can detect this by checking the
* size we originally found against the region's current size. (The
* region's current size has to be final, the creator finished growing
* it before releasing the environment for us to lock.)
*/
if (rp->size != size) {
err_unlock: MUTEX_UNLOCK(dbenv, &renv->mutex);
goto retry;
}
/* Increment the reference count. */
++renv->refcnt;
/*
* If our caller wants them, return the flags this environment was
* initialized with.
*/
if (init_flagsp != NULL)
*init_flagsp = renv->init_flags;
/* Discard our lock. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
/*
* Fault the pages into memory. Note, do this AFTER releasing the
* lock, because we're only reading the pages, not writing them.
*/
(void)__db_faultmem(dbenv, infop->primary, rp->size, 0);
/* Everything looks good, we're done. */
dbenv->reginfo = infop;
return (0);
creation:
/* Create the environment region. */
F_SET(infop, REGION_CREATE);
/*
* Allocate room for 50 REGION structures plus overhead (we're going
* to use this space for last-ditch allocation requests), although we
* should never need anything close to that.
*
* Encryption passwds are stored in the env region. Add that in too.
*/
memset(&tregion, 0, sizeof(tregion));
tregion.size = (roff_t)(50 * sizeof(REGION) +
dbenv->passwd_len + 2048);
tregion.segid = INVALID_REGION_SEGID;
if ((ret = __os_r_attach(dbenv, infop, &tregion)) != 0)
goto err;
/*
* Fault the pages into memory. Note, do this BEFORE we initialize
* anything, because we're writing the pages, not just reading them.
*/
(void)__db_faultmem(dbenv, infop->addr, tregion.size, 1);
/*
* The first object in the region is the REGENV structure. This is
* different from the other regions, and, from everything else in
* this region, where all objects are allocated from the pool, i.e.,
* there aren't any fixed locations. The remaining space is made
* available for later allocation.
*
* The allocation space must be size_t aligned, because that's what
* the initialization routine is going to store there. To make sure
* that happens, the REGENV structure was padded with a final size_t.
* No other region needs to worry about it because all of them treat
* the entire region as allocation space.
*
* Set the primary reference and correct the "addr" value to reference
* the shalloc region. Note, this requires that we "uncorrect" it at
* region detach, and that all of our offsets (R_ADDR/R_OFFSET) will be
* shifted as well, but that should be fine.
*/
infop->primary = R_ADDR(infop, 0);
infop->addr = (u_int8_t *)infop->addr + sizeof(REGENV);
__db_shalloc_init(infop->addr, tregion.size - sizeof(REGENV));
/*
* Initialize the rest of the REGENV structure, except for the magic
* number which validates the file/environment.
*/
renv = infop->primary;
renv->envpanic = 0;
db_version(&renv->majver, &renv->minver, &renv->patch);
SH_LIST_INIT(&renv->regionq);
renv->refcnt = 1;
renv->cipher_off = INVALID_ROFF;
renv->rep_off = INVALID_ROFF;
/*
* Initialize init_flags to store the flags that any other environment
* handle that uses DB_JOINENV to join this environment will need.
*/
renv->init_flags = (init_flagsp == NULL) ? 0 : *init_flagsp;
/*
* Lock the environment.
*
* Check the lock call return. This is the first lock we initialize
* and acquire, and we have to know if it fails. (It CAN fail, e.g.,
* SunOS, when using fcntl(2) for locking and using an in-memory
* filesystem as the database home. But you knew that, I'm sure -- it
* probably wasn't even worth mentioning.)
*/
if ((ret = __db_mutex_setup(dbenv, infop, &renv->mutex,
MUTEX_NO_RECORD | MUTEX_NO_RLOCK)) != 0) {
__db_err(dbenv, "%s: unable to initialize environment lock: %s",
infop->name, db_strerror(ret));
goto err;
}
if (!F_ISSET(&renv->mutex, MUTEX_IGNORE) &&
(ret = __db_mutex_lock(dbenv, &renv->mutex)) != 0) {
__db_err(dbenv, "%s: unable to acquire environment lock: %s",
infop->name, db_strerror(ret));
goto err;
}
/*
* Get the underlying REGION structure for this environment. Note,
* we created the underlying OS region before we acquired the REGION
* structure, which is backwards from the normal procedure. Update
* the REGION structure.
*/
if ((ret = __db_des_get(dbenv, infop, infop, &rp)) != 0) {
find_err: __db_err(dbenv,
"%s: unable to find environment", infop->name);
if (ret == 0)
ret = EINVAL;
goto err;
}
infop->rp = rp;
rp->size = tregion.size;
rp->segid = tregion.segid;
/*
* !!!
* If we create an environment where regions are public and in system
* memory, we have to inform processes joining the environment how to
* attach to the shared memory segment. So, we write the shared memory
* identifier into the file, to be read by those other processes.
*
* XXX
* This is really OS-layer information, but I can't see any easy way
* to move it down there without passing down information that it has
* no right to know, e.g., that this is the one-and-only REGENV region
* and not some other random region.
*/
if (tregion.segid != INVALID_REGION_SEGID) {
ref.size = tregion.size;
ref.segid = tregion.segid;
if ((ret = __os_write(
dbenv, dbenv->lockfhp, &ref, sizeof(ref), &nrw)) != 0) {
__db_err(dbenv,
"%s: unable to write out public environment ID: %s",
infop->name, db_strerror(ret));
goto err;
}
}
/*
* If not doing thread locking, we need to save the file handle for
* fcntl(2) locking. Otherwise, discard the handle, we no longer
* need it, and the less contact between the buffer cache and the VM,
* the better.
*/
#if defined(HAVE_MUTEX_THREADS)
if (F_ISSET(dbenv->lockfhp, DB_FH_VALID))
__os_closehandle(dbenv, dbenv->lockfhp);
#endif
/* Validate the file. */
renv->magic = DB_REGION_MAGIC;
/* Discard our lock. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
/* Everything looks good, we're done. */
dbenv->reginfo = infop;
return (0);
err:
retry: /* Close any open file handle. */
if (F_ISSET(dbenv->lockfhp, DB_FH_VALID))
(void)__os_closehandle(dbenv, dbenv->lockfhp);
/*
* If we joined or created the region, detach from it. If we created
* it, destroy it. Note, there's a path in the above code where we're
* using a temporary REGION structure because we haven't yet allocated
* the real one. In that case the region address (addr) will be filled
* in, but the REGION pointer (rp) won't. Fix it.
*/
if (infop->addr != NULL) {
if (infop->rp == NULL)
infop->rp = &tregion;
/* Reset the addr value that we "corrected" above. */
infop->addr = infop->primary;
(void)__os_r_detach(dbenv,
infop, F_ISSET(infop, REGION_CREATE));
}
/* Free the allocated name and/or REGINFO structure. */
if (infop->name != NULL)
__os_free(dbenv, infop->name);
__os_free(dbenv, infop);
/* If we had a temporary error, wait awhile and try again. */
if (ret == 0) {
if (++retry_cnt > 3) {
__db_err(dbenv, "unable to join the environment");
ret = EAGAIN;
} else {
__os_sleep(dbenv, retry_cnt * 3, 0);
goto loop;
}
}
return (ret);
}
/*
* __db_e_detach --
* Detach from the environment.
*
* PUBLIC: int __db_e_detach __P((DB_ENV *, int));
*/
int
__db_e_detach(dbenv, destroy)
DB_ENV *dbenv;
int destroy;
{
REGENV *renv;
REGINFO *infop;
infop = dbenv->reginfo;
renv = infop->primary;
if (F_ISSET(dbenv, DB_ENV_PRIVATE))
destroy = 1;
/* Lock the environment. */
MUTEX_LOCK(dbenv, &renv->mutex);
/* Decrement the reference count. */
if (renv->refcnt == 0) {
__db_err(dbenv,
"region %lu (environment): reference count went negative",
infop->rp->id);
} else
--renv->refcnt;
/* Release the lock. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
/* Close the locking file handle. */
if (F_ISSET(dbenv->lockfhp, DB_FH_VALID))
(void)__os_closehandle(dbenv, dbenv->lockfhp);
/* Reset the addr value that we "corrected" above. */
infop->addr = infop->primary;
/*
* If we are destroying the environment, we need to
* destroy any system resources backing the mutex, as well
* as any system resources that the replication system may have
* acquired and put in the main region.
*
* Do these now before we free the memory in __os_r_detach.
*/
if (destroy) {
__rep_region_destroy(dbenv);
__db_mutex_destroy(&renv->mutex);
__db_mutex_destroy(&infop->rp->mutex);
}
/*
* Release the region, and kill our reference.
*
* We set the DB_ENV->reginfo field to NULL here and discard its memory.
* DB_ENV->remove calls __dbenv_remove to do the region remove, and
* __dbenv_remove attached and then detaches from the region. We don't
* want to return to DB_ENV->remove with a non-NULL DB_ENV->reginfo
* field because it will attempt to detach again as part of its cleanup.
*/
(void)__os_r_detach(dbenv, infop, destroy);
if (infop->name != NULL)
__os_free(dbenv, infop->name);
__os_free(dbenv, dbenv->reginfo);
dbenv->reginfo = NULL;
return (0);
}
/*
* __db_e_remove --
* Discard an environment if it's not in use.
*
* PUBLIC: int __db_e_remove __P((DB_ENV *, u_int32_t));
*/
int
__db_e_remove(dbenv, flags)
DB_ENV *dbenv;
u_int32_t flags;
{
REGENV *renv;
REGINFO *infop, reginfo;
REGION *rp;
u_int32_t db_env_reset;
int force, ret;
force = LF_ISSET(DB_FORCE) ? 1 : 0;
/*
* This routine has to walk a nasty line between not looking into
* the environment (which may be corrupted after an app or system
* crash), and removing everything that needs removing. What we
* do is:
* 1. Connect to the environment (so it better be OK).
* 2. If the environment is in use (reference count is non-zero),
* return EBUSY.
* 3. Overwrite the magic number so that any threads of control
* attempting to connect will backoff and retry.
* 4. Walk the list of regions. Connect to each region and then
* disconnect with the destroy flag set. This shouldn't cause
* any problems, even if the region is corrupted, because we
* should never be looking inside the region.
* 5. Walk the list of files in the directory, unlinking any
* files that match a region name. Unlink the environment
* file last.
*
* If the force flag is set, we do not acquire any locks during this
* process.
*/
db_env_reset = F_ISSET(dbenv, DB_ENV_NOLOCKING | DB_ENV_NOPANIC);
if (force)
F_SET(dbenv, DB_ENV_NOLOCKING);
F_SET(dbenv, DB_ENV_NOPANIC);
/* Join the environment. */
if ((ret = __db_e_attach(dbenv, NULL)) != 0) {
/*
* If we can't join it, we assume that's because it doesn't
* exist. It would be better to know why we failed, but it
* probably isn't important.
*/
ret = 0;
if (force)
goto remfiles;
goto done;
}
infop = dbenv->reginfo;
renv = infop->primary;
/* Lock the environment. */
MUTEX_LOCK(dbenv, &renv->mutex);
/*
* If it's in use, we're done unless we're forcing the issue or the
* environment has panic'd. (Presumably, if the environment panic'd,
* the thread holding the reference count may not have cleaned up.)
*/
if (renv->refcnt == 1 || renv->envpanic == 1 || force) {
/*
* Set the panic flag and overwrite the magic number.
*
* !!!
* From this point on, there's no going back, we pretty
* much ignore errors, and just whack on whatever we can.
*/
renv->envpanic = 1;
renv->magic = 0;
/*
* Unlock the environment. We should no longer need the lock
* because we've poisoned the pool, but we can't continue to
* hold it either, because other routines may want it.
*/
MUTEX_UNLOCK(dbenv, &renv->mutex);
/*
* Attach to each sub-region and destroy it.
*
* !!!
* The REGION_CREATE_OK flag is set for Windows/95 -- regions
* are zero'd out when the last reference to the region goes
* away, in which case the underlying OS region code requires
* callers be prepared to create the region in order to join it.
*/
memset(®info, 0, sizeof(reginfo));
restart: for (rp = SH_LIST_FIRST(&renv->regionq, __db_region);
rp != NULL; rp = SH_LIST_NEXT(rp, q, __db_region)) {
if (rp->type == REGION_TYPE_ENV)
continue;
reginfo.id = rp->id;
reginfo.flags = REGION_CREATE_OK;
if ((ret = __db_r_attach(dbenv, ®info, 0)) != 0) {
__db_err(dbenv,
"region %s attach: %s", db_strerror(ret));
continue;
}
R_UNLOCK(dbenv, ®info);
if ((ret = __db_r_detach(dbenv, ®info, 1)) != 0) {
__db_err(dbenv,
"region detach: %s", db_strerror(ret));
continue;
}
/*
* If we have an error, we continue so we eventually
* reach the end of the list. If we succeed, restart
* the list because it was relinked when we destroyed
* the entry.
*/
goto restart;
}
/* Destroy the environment's region. */
(void)__db_e_detach(dbenv, 1);
/* Discard any remaining physical files. */
remfiles: (void)__db_e_remfile(dbenv);
} else {
/* Unlock the environment. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
/* Discard the environment. */
(void)__db_e_detach(dbenv, 0);
ret = EBUSY;
}
done: F_CLR(dbenv, DB_ENV_NOLOCKING | DB_ENV_NOPANIC);
F_SET(dbenv, db_env_reset);
return (ret);
}
/*
* __db_e_remfile --
* Discard any region files in the filesystem.
*/
static int
__db_e_remfile(dbenv)
DB_ENV *dbenv;
{
static char *old_region_names[] = {
"__db_lock.share",
"__db_log.share",
"__db_mpool.share",
"__db_txn.share",
NULL
};
int cnt, fcnt, lastrm, ret;
u_int8_t saved_byte;
const char *dir;
char *p, **names, *path, buf[sizeof(DB_REGION_FMT) + 20];
/* Get the full path of a file in the environment. */
(void)snprintf(buf, sizeof(buf), "%s", DB_REGION_ENV);
if ((ret = __db_appname(dbenv, DB_APP_NONE, buf, 0, NULL, &path)) != 0)
return (ret);
/* Get the parent directory for the environment. */
if ((p = __db_rpath(path)) == NULL) {
p = path;
saved_byte = *p;
dir = PATH_DOT;
} else {
saved_byte = *p;
*p = '\0';
dir = path;
}
/* Get the list of file names. */
if ((ret = __os_dirlist(dbenv, dir, &names, &fcnt)) != 0)
__db_err(dbenv, "%s: %s", dir, db_strerror(ret));
/* Restore the path, and free it. */
*p = saved_byte;
__os_free(dbenv, path);
if (ret != 0)
return (ret);
/*
* Search for valid region names, and remove them. We remove the
* environment region last, because it's the key to this whole mess.
*/
for (lastrm = -1, cnt = fcnt; --cnt >= 0;) {
if (strlen(names[cnt]) != DB_REGION_NAME_LENGTH ||
memcmp(names[cnt], DB_REGION_FMT, DB_REGION_NAME_NUM) != 0)
continue;
if (strcmp(names[cnt], DB_REGION_ENV) == 0) {
lastrm = cnt;
continue;
}
for (p = names[cnt] + DB_REGION_NAME_NUM;
*p != '\0' && isdigit((int)*p); ++p)
;
if (*p != '\0')
continue;
if (__db_appname(dbenv,
DB_APP_NONE, names[cnt], 0, NULL, &path) == 0) {
if (F_ISSET(dbenv, DB_ENV_OVERWRITE))
(void)__db_overwrite(dbenv, path);
(void)__os_unlink(dbenv, path);
__os_free(dbenv, path);
}
}
if (lastrm != -1)
if (__db_appname(dbenv,
DB_APP_NONE, names[lastrm], 0, NULL, &path) == 0) {
if (F_ISSET(dbenv, DB_ENV_OVERWRITE))
(void)__db_overwrite(dbenv, path);
(void)__os_unlink(dbenv, path);
__os_free(dbenv, path);
}
__os_dirfree(dbenv, names, fcnt);
/*
* !!!
* Backward compatibility -- remove region files from releases
* before 2.8.XX.
*/
for (names = (char **)old_region_names; *names != NULL; ++names)
if (__db_appname(dbenv,
DB_APP_NONE, *names, 0, NULL, &path) == 0) {
(void)__os_unlink(dbenv, path);
__os_free(dbenv, path);
}
return (0);
}
/*
* __db_e_stat
* Statistics for the environment.
*
* PUBLIC: int __db_e_stat __P((DB_ENV *,
* PUBLIC: REGENV *, REGION *, int *, u_int32_t));
*/
int
__db_e_stat(dbenv, arg_renv, arg_regions, arg_regions_cnt, flags)
DB_ENV *dbenv;
REGENV *arg_renv;
REGION *arg_regions;
int *arg_regions_cnt;
u_int32_t flags;
{
REGENV *renv;
REGINFO *infop;
REGION *rp;
int n, ret;
infop = dbenv->reginfo;
renv = infop->primary;
rp = infop->rp;
if ((ret = __db_fchk(dbenv,
"DB_ENV->stat", flags, DB_STAT_CLEAR)) != 0)
return (ret);
/* Lock the environment. */
MUTEX_LOCK(dbenv, &rp->mutex);
*arg_renv = *renv;
if (LF_ISSET(DB_STAT_CLEAR)) {
renv->mutex.mutex_set_nowait = 0;
renv->mutex.mutex_set_wait = 0;
}
for (n = 0, rp = SH_LIST_FIRST(&renv->regionq, __db_region);
n < *arg_regions_cnt && rp != NULL;
++n, rp = SH_LIST_NEXT(rp, q, __db_region)) {
arg_regions[n] = *rp;
if (LF_ISSET(DB_STAT_CLEAR)) {
rp->mutex.mutex_set_nowait = 0;
rp->mutex.mutex_set_wait = 0;
}
}
/* Release the lock. */
rp = infop->rp;
MUTEX_UNLOCK(dbenv, &rp->mutex);
*arg_regions_cnt = n == 0 ? n : n - 1;
return (0);
}
/*
* __db_r_attach
* Join/create a region.
*
* PUBLIC: int __db_r_attach __P((DB_ENV *, REGINFO *, size_t));
*/
int
__db_r_attach(dbenv, infop, size)
DB_ENV *dbenv;
REGINFO *infop;
size_t size;
{
REGENV *renv;
REGION *rp;
int ret;
char buf[sizeof(DB_REGION_FMT) + 20];
renv = ((REGINFO *)dbenv->reginfo)->primary;
/* Lock the environment. */
MUTEX_LOCK(dbenv, &renv->mutex);
/*
* Find or create a REGION structure for this region. If we create
* it, the REGION_CREATE flag will be set in the infop structure.
*/
F_CLR(infop, REGION_CREATE);
if ((ret = __db_des_get(dbenv, dbenv->reginfo, infop, &rp)) != 0) {
MUTEX_UNLOCK(dbenv, &renv->mutex);
return (ret);
}
infop->rp = rp;
infop->type = rp->type;
infop->id = rp->id;
/* If we're creating the region, set the desired size. */
if (F_ISSET(infop, REGION_CREATE))
rp->size = (roff_t)size;
/* Join/create the underlying region. */
(void)snprintf(buf, sizeof(buf), DB_REGION_FMT, infop->id);
if ((ret = __db_appname(dbenv,
DB_APP_NONE, buf, 0, NULL, &infop->name)) != 0)
goto err;
if ((ret = __os_r_attach(dbenv, infop, rp)) != 0)
goto err;
/*
* Fault the pages into memory. Note, do this BEFORE we initialize
* anything because we're writing pages in created regions, not just
* reading them.
*/
(void)__db_faultmem(dbenv,
infop->addr, rp->size, F_ISSET(infop, REGION_CREATE));
/*
* !!!
* The underlying layer may have just decided that we are going
* to create the region. There are various system issues that
* can result in a useless region that requires re-initialization.
*
* If we created the region, initialize it for allocation.
*/
if (F_ISSET(infop, REGION_CREATE)) {
((REGION *)(infop->addr))->magic = DB_REGION_MAGIC;
(void)__db_shalloc_init(infop->addr, rp->size);
}
/*
* If the underlying REGION isn't the environment, acquire a lock
* for it and release our lock on the environment.
*/
if (infop->type != REGION_TYPE_ENV) {
MUTEX_LOCK(dbenv, &rp->mutex);
MUTEX_UNLOCK(dbenv, &renv->mutex);
}
return (0);
/* Discard the underlying region. */
err: if (infop->addr != NULL)
(void)__os_r_detach(dbenv,
infop, F_ISSET(infop, REGION_CREATE));
infop->rp = NULL;
infop->id = INVALID_REGION_ID;
/* Discard the REGION structure if we created it. */
if (F_ISSET(infop, REGION_CREATE)) {
(void)__db_des_destroy(dbenv, rp);
F_CLR(infop, REGION_CREATE);
}
/* Release the environment lock. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
return (ret);
}
/*
* __db_r_detach --
* Detach from a region.
*
* PUBLIC: int __db_r_detach __P((DB_ENV *, REGINFO *, int));
*/
int
__db_r_detach(dbenv, infop, destroy)
DB_ENV *dbenv;
REGINFO *infop;
int destroy;
{
REGENV *renv;
REGION *rp;
int ret, t_ret;
renv = ((REGINFO *)dbenv->reginfo)->primary;
rp = infop->rp;
if (F_ISSET(dbenv, DB_ENV_PRIVATE))
destroy = 1;
/* Lock the environment. */
MUTEX_LOCK(dbenv, &renv->mutex);
/* Acquire the lock for the REGION. */
MUTEX_LOCK(dbenv, &rp->mutex);
/*
* We need to call destroy on per-subsystem info before
* we free the memory associated with the region.
*/
if (destroy)
__db_region_destroy(dbenv, infop);
/* Detach from the underlying OS region. */
ret = __os_r_detach(dbenv, infop, destroy);
/* Release the REGION lock. */
MUTEX_UNLOCK(dbenv, &rp->mutex);
/* If we destroyed the region, discard the REGION structure. */
if (destroy &&
((t_ret = __db_des_destroy(dbenv, rp)) != 0) && ret == 0)
ret = t_ret;
/* Release the environment lock. */
MUTEX_UNLOCK(dbenv, &renv->mutex);
/* Destroy the structure. */
if (infop->name != NULL)
__os_free(dbenv, infop->name);
return (ret);
}
/*
* __db_des_get --
* Return a reference to the shared information for a REGION,
* optionally creating a new entry.
*/
static int
__db_des_get(dbenv, env_infop, infop, rpp)
DB_ENV *dbenv;
REGINFO *env_infop, *infop;
REGION **rpp;
{
REGENV *renv;
REGION *rp, *first_type;
u_int32_t maxid;
int ret;
/*
* !!!
* Called with the environment already locked.
*/
*rpp = NULL;
renv = env_infop->primary;
/*
* If the caller wants to join a region, walk through the existing
* regions looking for a matching ID (if ID specified) or matching
* type (if type specified). If we return based on a matching type
* return the "primary" region, that is, the first region that was
* created of this type.
*
* Track the maximum region ID so we can allocate a new region,
* note that we have to start at 1 because the primary environment
* uses ID == 1.
*/
maxid = REGION_ID_ENV;
for (first_type = NULL,
rp = SH_LIST_FIRST(&renv->regionq, __db_region);
rp != NULL; rp = SH_LIST_NEXT(rp, q, __db_region)) {
if (infop->id != INVALID_REGION_ID) {
if (infop->id == rp->id)
break;
continue;
}
if (infop->type == rp->type &&
F_ISSET(infop, REGION_JOIN_OK) &&
(first_type == NULL || first_type->id > rp->id))
first_type = rp;
if (rp->id > maxid)
maxid = rp->id;
}
if (rp == NULL)
rp = first_type;
/*
* If we didn't find a region and we can't create the region, fail.
* The caller generates any error message.
*/
if (rp == NULL && !F_ISSET(infop, REGION_CREATE_OK))
return (ENOENT);
/*
* If we didn't find a region, create and initialize a REGION structure
* for the caller. If id was set, use that value, otherwise we use the
* next available ID.
*/
if (rp == NULL) {
if ((ret = __db_shalloc(env_infop->addr,
sizeof(REGION), MUTEX_ALIGN, &rp)) != 0)
return (ret);
/* Initialize the region. */
memset(rp, 0, sizeof(*rp));
if ((ret = __db_mutex_setup(dbenv, env_infop, &rp->mutex,
MUTEX_NO_RECORD | MUTEX_NO_RLOCK)) != 0) {
__db_shalloc_free(env_infop->addr, rp);
return (ret);
}
rp->segid = INVALID_REGION_SEGID;
/*
* Set the type and ID; if no region ID was specified,
* allocate one.
*/
rp->type = infop->type;
rp->id = infop->id == INVALID_REGION_ID ? maxid + 1 : infop->id;
SH_LIST_INSERT_HEAD(&renv->regionq, rp, q, __db_region);
F_SET(infop, REGION_CREATE);
}
*rpp = rp;
return (0);
}
/*
* __db_des_destroy --
* Destroy a reference to a REGION.
*/
static int
__db_des_destroy(dbenv, rp)
DB_ENV *dbenv;
REGION *rp;
{
REGINFO *infop;
/*
* !!!
* Called with the environment already locked.
*/
infop = dbenv->reginfo;
SH_LIST_REMOVE(rp, q, __db_region);
__db_mutex_destroy(&rp->mutex);
__db_shalloc_free(infop->addr, rp);
return (0);
}
/*
* __db_faultmem --
* Fault the region into memory.
*/
static int
__db_faultmem(dbenv, addr, size, created)
DB_ENV *dbenv;
void *addr;
size_t size;
int created;
{
int ret;
u_int8_t *p, *t;
/*
* It's sometimes significantly faster to page-fault in all of the
* region's pages before we run the application, as we see nasty
* side-effects when we page-fault while holding various locks, i.e.,
* the lock takes a long time to acquire because of the underlying
* page fault, and the other threads convoy behind the lock holder.
*
* If we created the region, we write a non-zero value so that the
* system can't cheat. If we're just joining the region, we can
* only read the value and try to confuse the compiler sufficiently
* that it doesn't figure out that we're never really using it.
*/
ret = 0;
if (F_ISSET(dbenv, DB_ENV_REGION_INIT)) {
if (created)
for (p = addr, t = (u_int8_t *)addr + size;
p < t; p += OS_VMPAGESIZE)
p[0] = 0xdb;
else
for (p = addr, t = (u_int8_t *)addr + size;
p < t; p += OS_VMPAGESIZE)
ret |= p[0];
}
return (ret);
}
/*
* __db_region_destroy --
* Destroy per-subsystem region information.
* Called with the region already locked.
*/
static void
__db_region_destroy(dbenv, infop)
DB_ENV *dbenv;
REGINFO *infop;
{
switch (infop->type) {
case REGION_TYPE_LOCK:
__lock_region_destroy(dbenv, infop);
break;
case REGION_TYPE_LOG:
__log_region_destroy(dbenv, infop);
break;
case REGION_TYPE_MPOOL:
__mpool_region_destroy(dbenv, infop);
break;
case REGION_TYPE_TXN:
__txn_region_destroy(dbenv, infop);
break;
case REGION_TYPE_ENV:
case REGION_TYPE_MUTEX:
break;
default:
DB_ASSERT(0);
break;
}
}
|