Initial revision

CVS patchset: 4644
CVS date: 2001/03/21 18:33:35

1 files changed, 440 insertions, 0 deletions

diff --git a/db/os_vxworks/os_map.c b/db/os_vxworks/os_map.c
new file mode 100644
index 000000000..7397995d1
--- /dev/null
+++ b/db/os_vxworks/os_map.c
@@ -0,0 +1,440 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1998, 1999, 2000
+ *	Sleepycat Software.  All rights reserved.
+ *
+ * This code is derived from software contributed to Sleepycat Software by
+ * Frederick G.M. Roeber of Netscape Communications Corp.
+ */
+
+#include "db_config.h"
+
+#ifndef lint
+static const char revid[] = "$Id: os_map.c,v 1.14 2000/12/04 19:01:43 sue Exp $";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+#include <string.h>
+#endif
+
+#include "db_int.h"
+#include "common_ext.h"
+
+/*
+ * DB uses memory-mapped files for two things:
+ *	faster access of read-only databases, and
+ *	shared memory for process synchronization and locking.
+ * The code carefully does not mix the two uses.  The first-case uses are
+ * actually written such that memory-mapping isn't really required -- it's
+ * merely a convenience -- so we don't have to worry much about it.  In the
+ * second case, it's solely used as a shared memory mechanism, so that's
+ * all we have to replace.
+ *
+ * All memory in VxWorks is shared, and a task can allocate memory and keep
+ * notes.  So I merely have to allocate memory, remember the "filename" for
+ * that memory, and issue small-integer segment IDs which index the list of
+ * these shared-memory segments. Subsequent opens are checked against the
+ * list of already open segments.
+ */
+typedef struct {
+	void *segment;			/* Segment address. */
+	u_int32_t size;			/* Segment size. */
+	char *name;			/* Segment name. */
+	long segid;			/* Segment ID. */
+} os_segdata_t;
+
+static os_segdata_t *__os_segdata;	/* Segment table. */
+static int __os_segdata_size;		/* Segment table size. */
+
+#define	OS_SEGDATA_STARTING_SIZE 16
+#define	OS_SEGDATA_INCREMENT	 16
+
+static int __os_segdata_allocate
+	       __P((DB_ENV *, const char *, REGINFO *, REGION *));
+static int __os_segdata_find_byname
+	       __P((DB_ENV *, const char *, REGINFO *, REGION *));
+static int __os_segdata_init __P((DB_ENV *));
+static int __os_segdata_new __P((DB_ENV *, int *));
+static int __os_segdata_release __P((DB_ENV *, REGION *, int));
+
+/*
+ * __os_r_sysattach --
+ *	Create/join a shared memory region.
+ *
+ * PUBLIC: int __os_r_sysattach __P((DB_ENV *, REGINFO *, REGION *));
+ */
+int
+__os_r_sysattach(dbenv, infop, rp)
+	DB_ENV *dbenv;
+	REGINFO *infop;
+	REGION *rp;
+{
+	int ret;
+
+	if (__os_segdata == NULL)
+		__os_segdata_init(dbenv);
+
+	DB_BEGIN_SINGLE_THREAD;
+
+	/* Try to find an already existing segment. */
+	ret = __os_segdata_find_byname(dbenv, infop->name, infop, rp);
+
+	/*
+	 * If we are trying to join a region, it is easy, either we
+	 * found it and we return, or we didn't find it and we return
+	 * an error that it doesn't exist.
+	 */
+	if (!F_ISSET(infop, REGION_CREATE)) {
+		if (ret != 0) {
+			__db_err(dbenv, "segment %s does not exist",
+			    infop->name);
+			ret = EAGAIN;
+		}
+		goto out;
+	}
+
+	/*
+	 * If we get here, we are trying to create the region.
+	 * There are several things to consider:
+	 * - if we have an error (not a found or not-found value), return.
+	 * - they better have shm_key set.
+	 * - if the region is already there (ret == 0 from above),
+	 * assume the application crashed and we're restarting.
+	 * Delete the old region.
+	 * - try to create the region.
+	 */
+	if (ret != 0 && ret != ENOENT)
+		goto out;
+
+	if (dbenv->shm_key == INVALID_REGION_SEGID) {
+		__db_err(dbenv, "no base shared memory ID specified");
+		ret = EAGAIN;
+		goto out;
+	}
+	if (ret == 0 && __os_segdata_release(dbenv, rp, 1) != 0) {
+		__db_err(dbenv,
+		    "key: %ld: shared memory region already exists",
+		    dbenv->shm_key + (infop->id - 1));
+		ret = EAGAIN;
+		goto out;
+	}
+
+	ret = __os_segdata_allocate(dbenv, infop->name, infop, rp);
+out:
+	DB_END_SINGLE_THREAD;
+	return (ret);
+}
+
+/*
+ * __os_r_sysdetach --
+ *	Detach from a shared region.
+ *
+ * PUBLIC: int __os_r_sysdetach __P((DB_ENV *, REGINFO *, int));
+ */
+int
+__os_r_sysdetach(dbenv, infop, destroy)
+	DB_ENV *dbenv;
+	REGINFO *infop;
+	int destroy;
+{
+	/*
+	 * If just detaching, there is no mapping to discard.
+	 * If destroying, remove the region.
+	 */
+	if (destroy)
+		return (__os_segdata_release(dbenv, infop->rp, 0));
+	return (0);
+}
+
+/*
+ * __os_mapfile --
+ *	Map in a shared memory file.
+ *
+ * PUBLIC: int __os_mapfile __P((DB_ENV *,
+ * PUBLIC:    char *, DB_FH *, size_t, int, void **));
+ */
+int
+__os_mapfile(dbenv, path, fhp, len, is_rdonly, addrp)
+	DB_ENV *dbenv;
+	char *path;
+	DB_FH *fhp;
+	int is_rdonly;
+	size_t len;
+	void **addrp;
+{
+	/* We cannot map in regular files in VxWorks. */
+	COMPQUIET(dbenv, NULL);
+	COMPQUIET(path, NULL);
+	COMPQUIET(fhp, NULL);
+	COMPQUIET(is_rdonly, 0);
+	COMPQUIET(len, 0);
+	COMPQUIET(addrp, NULL);
+	return (EINVAL);
+}
+
+/*
+ * __os_unmapfile --
+ *	Unmap the shared memory file.
+ *
+ * PUBLIC: int __os_unmapfile __P((DB_ENV *, void *, size_t));
+ */
+int
+__os_unmapfile(dbenv, addr, len)
+	DB_ENV *dbenv;
+	void *addr;
+	size_t len;
+{
+	/* We cannot map in regular files in VxWorks. */
+	COMPQUIET(addr, NULL);
+	COMPQUIET(len, 0);
+	return (EINVAL);
+}
+
+/*
+ * __os_segdata_init --
+ *	Initializes the library's table of shared memory segments.
+ *	Called once on the first time through __os_segdata_new().
+ */
+static int
+__os_segdata_init(dbenv)
+	DB_ENV *dbenv;
+{
+	int ret;
+
+	if (__os_segdata != NULL) {
+		__db_err(dbenv, "shared memory segment already exists");
+		return (EEXIST);
+	}
+
+	/*
+	 * The lock init call returns a locked lock.
+	 */
+	DB_BEGIN_SINGLE_THREAD;
+	__os_segdata_size = OS_SEGDATA_STARTING_SIZE;
+	ret = __os_calloc(dbenv,
+	    __os_segdata_size, sizeof(os_segdata_t), &__os_segdata);
+	DB_END_SINGLE_THREAD;
+	return (ret);
+}
+
+/*
+ * __os_segdata_destroy --
+ *	Destroys the library's table of shared memory segments.  It also
+ *	frees all linked data: the segments themselves, and their names.
+ *	Currently not called.  This function should be called if the
+ *	user creates a function to unload or shutdown.
+ *
+ * PUBLIC: int __os_segdata_destroy __P((void));
+ */
+int
+__os_segdata_destroy()
+{
+	os_segdata_t *p;
+	int i;
+
+	if (__os_segdata == NULL)
+		return (0);
+
+	DB_BEGIN_SINGLE_THREAD;
+	for (i = 0; i < __os_segdata_size; i++) {
+		p = &__os_segdata[i];
+		if (p->name != NULL) {
+			__os_freestr(p->name);
+			p->name = NULL;
+		}
+		if (p->segment != NULL) {
+			__os_free(p->segment, p->size);
+			p->segment = NULL;
+		}
+		p->size = 0;
+	}
+
+	__os_free(__os_segdata, __os_segdata_size * sizeof(os_segdata_t));
+	__os_segdata = NULL;
+	__os_segdata_size = 0;
+	DB_END_SINGLE_THREAD;
+
+	return (0);
+}
+
+/*
+ * __os_segdata_allocate --
+ *	Creates a new segment of the specified size, optionally with the
+ *	specified name.
+ *
+ * Assumes it is called with the SEGDATA lock taken.
+ */
+static int
+__os_segdata_allocate(dbenv, name, infop, rp)
+	DB_ENV *dbenv;
+	const char *name;
+	REGINFO *infop;
+	REGION *rp;
+{
+	os_segdata_t *p;
+	int id, ret;
+
+	if ((ret = __os_segdata_new(dbenv, &id)) != 0)
+		return (ret);
+
+	p = &__os_segdata[id];
+	if ((ret = __os_calloc(dbenv, 1, rp->size, &p->segment)) != 0)
+		return (ret);
+	if ((ret = __os_strdup(dbenv, name, &p->name)) != 0) {
+		__os_free(p->segment, rp->size);
+		p->segment = NULL;
+		return (ret);
+	}
+	p->size = rp->size;
+	p->segid = dbenv->shm_key + infop->id - 1;
+
+	infop->addr = p->segment;
+	rp->segid = id;
+
+	return (0);
+}
+
+/*
+ * __os_segdata_new --
+ *	Finds a new segdata slot.  Does not initialise it, so the fd returned
+ *	is only valid until you call this again.
+ *
+ * Assumes it is called with the SEGDATA lock taken.
+ */
+static int
+__os_segdata_new(dbenv, segidp)
+	DB_ENV *dbenv;
+	int *segidp;
+{
+	os_segdata_t *p;
+	int i, newsize, ret;
+
+	if (__os_segdata == NULL) {
+		__db_err(dbenv, "shared memory segment not initialized");
+		return (EAGAIN);
+	}
+
+	for (i = 0; i < __os_segdata_size; i++) {
+		p = &__os_segdata[i];
+		if (p->segment == NULL) {
+			*segidp = i;
+			return (0);
+		}
+	}
+
+	/*
+	 * No more free slots, expand.
+	 */
+	newsize = __os_segdata_size + OS_SEGDATA_INCREMENT;
+	if ((ret = __os_realloc(dbenv, newsize * sizeof(os_segdata_t),
+	    NULL, &__os_segdata)) != 0)
+		return (ret);
+	memset(&__os_segdata[__os_segdata_size],
+	    0, OS_SEGDATA_INCREMENT * sizeof(os_segdata_t));
+
+	*segidp = __os_segdata_size;
+	__os_segdata_size = newsize;
+
+	return (0);
+}
+
+/*
+ * __os_segdata_find_byname --
+ *	Finds a segment by its name and shm_key.
+ *
+ * Assumes it is called with the SEGDATA lock taken.
+ *
+ * PUBLIC: __os_segdata_find_byname
+ * PUBLIC:     __P((DB_ENV *, const char *, REGINFO *, REGION *));
+ */
+static int
+__os_segdata_find_byname(dbenv, name, infop, rp)
+	DB_ENV *dbenv;
+	const char *name;
+	REGINFO *infop;
+	REGION *rp;
+{
+	os_segdata_t *p;
+	long segid;
+	int i;
+
+	if (__os_segdata == NULL) {
+		__db_err(dbenv, "shared memory segment not initialized");
+		return (EAGAIN);
+	}
+
+	if (name == NULL) {
+		__db_err(dbenv, "no segment name given");
+		return (EAGAIN);
+	}
+
+	/*
+	 * If we are creating the region, compute the segid.
+	 * If we are joining the region, we use the segid in the
+	 * index we are given.
+	 */
+	if (F_ISSET(infop, REGION_CREATE))
+		segid = dbenv->shm_key + (infop->id - 1);
+	else {
+		if (rp->segid >= __os_segdata_size ||
+		    rp->segid == INVALID_REGION_SEGID) {
+			__db_err(dbenv, "Invalid segment id given");
+			return (EAGAIN);
+		}
+		segid = __os_segdata[rp->segid].segid;
+	}
+	for (i = 0; i < __os_segdata_size; i++) {
+		p = &__os_segdata[i];
+		if (p->name != NULL && strcmp(name, p->name) == 0 &&
+		    p->segid == segid) {
+			infop->addr = p->segment;
+			rp->segid = i;
+			return (0);
+		}
+	}
+	return (ENOENT);
+}
+
+/*
+ * __os_segdata_release --
+ *	Free a segdata entry.
+ */
+static int
+__os_segdata_release(dbenv, rp, is_locked)
+	DB_ENV *dbenv;
+	REGION *rp;
+	int is_locked;
+{
+	os_segdata_t *p;
+
+	if (__os_segdata == NULL) {
+		__db_err(dbenv, "shared memory segment not initialized");
+		return (EAGAIN);
+	}
+
+	if (rp->segid < 0 || rp->segid >= __os_segdata_size) {
+		__db_err(dbenv, "segment id %ld out of range", rp->segid);
+		return (EINVAL);
+	}
+
+	if (is_locked == 0)
+		DB_BEGIN_SINGLE_THREAD;
+	p = &__os_segdata[rp->segid];
+	if (p->name != NULL) {
+		__os_freestr(p->name);
+		p->name = NULL;
+	}
+	if (p->segment != NULL) {
+		__os_free(p->segment, p->size);
+		p->segment = NULL;
+	}
+	p->size = 0;
+	if (is_locked == 0)
+		DB_END_SINGLE_THREAD;
+
+	/* Any shrink-table logic could go here */
+
+	return (0);
+}