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authorUlrich Drepper <drepper@redhat.com>1997-08-27 20:26:10 +0000
committerUlrich Drepper <drepper@redhat.com>1997-08-27 20:26:10 +0000
commit92f1da4da04a7a86ddee91be5eaf0b10c333ac64 (patch)
tree2a10ce9e4e407e7e5b5ca092ca0947d234b5ff60 /db2/mutex
parent22be878ecbc66606371bd33258f56e6711e6ba7a (diff)
downloadglibc-92f1da4da04a7a86ddee91be5eaf0b10c333ac64.tar.gz
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glibc-92f1da4da04a7a86ddee91be5eaf0b10c333ac64.zip
1997-08-10 19:17  Philip Blundell  <Philip.Blundell@pobox.com>

	* nss/nss_db/db-XXX.c: Include <db_185.h> not <db.h>.  Somebody
	should update this to use the new db API.
	* nss/nss_db/db-netgrp.c: Likewise.
	* nss/nss_db/db-alias.c: Likewise.
	* db2/Makefile: Makefile for db-2.x in glibc.

1997-08-27 21:20  Ulrich Drepper  <drepper@cygnus.com>

	* csu/Makefile (before-compile): New goal.  Make sure abi-tag.h
	is generated.
	[$(elf)=yes] (asm-CPPFLAGS): Make sure abi-tag.h file can be found.

	* Makeconfig [$(build-omitfp)=yes] (CFLAGS-.o): Add
	-D__USE_STRING_INLINES.
	* string/string.f: Move strnlen optimization after inclusion of
	<bits/string.h>.  Include <bits/string.h> only if __USE_STRING_INLINES
	is defined.
	* sysdeps/generic/memcpy.c: Undef memcpy to allow macro of this name
	in <bits/string.h>.
	* sysdeps/generic/memset.c: Likewise.
	* sysdeps/i386/string.h: i386 optimized string functions.
	* sysdeps/i386/i486string.h: i486+ optimized string functions.

	* Makefile (subdirs): Change db to db2.
	* shlib-versions: Bump libdb verion number to 3.
	* include/db.h: Include from db2 directory.
	* include/db_185.h: New file.
	* sysdeps/i386/Makefile [$(subdirs)=db2] (CPPFLAGS): Add macros
	to provide spinlock information for db2.
	* sysdeps/m68k/m68020/Makefile: New file.  Likewise.
	* sysdeps/sparc/Makefile: New file.  Likewise.
	* sysdeps/unix/sysv/linux/Makefile [$(subdirs)=db2] (CPPFLAGS):
	Add -DHAVE_LLSEEK.
	* db2/config.h: Hand-edited config file for db2 in glibc.
	* db2/compat.h: New file from db-2.3.4.
	* db2/db.h: Likewise.
	* db2/db_185.h: Likewise.
	* db2/db_int.h: Likewise.
	* db2/makedb.c: Likewise.
	* db2/btree/bt_close.c: Likewise.
	* db2/btree/bt_compare.c: Likewise.
	* db2/btree/bt_conv.c: Likewise.
	* db2/btree/bt_cursor.c: Likewise.
	* db2/btree/bt_delete.c: Likewise.
	* db2/btree/bt_open.c: Likewise.
	* db2/btree/bt_page.c: Likewise.
	* db2/btree/bt_put.c: Likewise.
	* db2/btree/bt_rec.c: Likewise.
	* db2/btree/bt_recno.c: Likewise.
	* db2/btree/btree_auto.c: Likewise.
	* db2/btree/bt_rsearch.c: Likewise.
	* db2/btree/bt_search.c: Likewise.
	* db2/btree/bt_split.c: Likewise.
	* db2/btree/bt_stat.c: Likewise.
	* db2/btree/btree.src: Likewise.
	* db2/common/db_appinit.c: Likewise.
	* db2/common/db_err.c: Likewise.
	* db2/common/db_byteorder.c: Likewise.
	* db2/common/db_apprec.c: Likewise.
	* db2/common/db_salloc.c: Likewise.
	* db2/common/db_log2.c: Likewise.
	* db2/common/db_region.c: Likewise.
	* db2/common/db_shash.c: Likewise.
	* db2/db/db.c: Likewise.
	* db2/db/db.src: Likewise.
	* db2/db/db_conv.c: Likewise.
	* db2/db/db_dispatch.c: Likewise.
	* db2/db/db_dup.c: Likewise.
	* db2/db/db_overflow.c: Likewise.
	* db2/db/db_pr.c: Likewise.
	* db2/db/db_rec.c: Likewise.
	* db2/db/db_ret.c: Likewise.
	* db2/db/db_thread.c: Likewise.
	* db2/db/db_auto.c: Likewise.
	* db2/db185/db185.c: Likewise.
	* db2/db185/db185_int.h: Likewise.
	* db2/dbm/dbm.c: Likewise.
	* db2/hash/hash.c: Likewise.
	* db2/hash/hash.src: Likewise.
	* db2/hash/hash_page.c: Likewise.
	* db2/hash/hash_conv.c: Likewise.
	* db2/hash/hash_debug.c: Likewise.
	* db2/hash/hash_stat.c: Likewise.
	* db2/hash/hash_rec.c: Likewise.
	* db2/hash/hash_dup.c: Likewise.
	* db2/hash/hash_func.c: Likewise.
	* db2/hash/hash_auto.c: Likewise.
	* db2/include/mp.h: Likewise.
	* db2/include/btree.h: Likewise.
	* db2/include/db.h.src: Likewise.
	* db2/include/db_int.h.src: Likewise.
	* db2/include/db_shash.h: Likewise.
	* db2/include/db_swap.h: Likewise.
	* db2/include/db_185.h.src: Likewise.
	* db2/include/txn.h: Likewise.
	* db2/include/db_am.h: Likewise.
	* db2/include/shqueue.h: Likewise.
	* db2/include/hash.h: Likewise.
	* db2/include/db_dispatch.h: Likewise.
	* db2/include/lock.h: Likewise.
	* db2/include/db_page.h: Likewise.
	* db2/include/log.h: Likewise.
	* db2/include/db_auto.h: Likewise.
	* db2/include/btree_auto.h: Likewise.
	* db2/include/hash_auto.h: Likewise.
	* db2/include/log_auto.h: Likewise.
	* db2/include/txn_auto.h: Likewise.
	* db2/include/db_ext.h: Likewise.
	* db2/include/btree_ext.h: Likewise.
	* db2/include/clib_ext.h: Likewise.
	* db2/include/common_ext.h: Likewise.
	* db2/include/hash_ext.h: Likewise.
	* db2/include/lock_ext.h: Likewise.
	* db2/include/log_ext.h: Likewise.
	* db2/include/mp_ext.h: Likewise.
	* db2/include/mutex_ext.h: Likewise.
	* db2/include/os_ext.h: Likewise.
	* db2/include/txn_ext.h: Likewise.
	* db2/include/cxx_int.h: Likewise.
	* db2/include/db_cxx.h: Likewise.
	* db2/include/queue.h: Likewise.
	* db2/lock/lock.c: Likewise.
	* db2/lock/lock_conflict.c: Likewise.
	* db2/lock/lock_util.c: Likewise.
	* db2/lock/lock_deadlock.c: Likewise.
	* db2/log/log.c: Likewise.
	* db2/log/log_get.c: Likewise.
	* db2/log/log.src: Likewise.
	* db2/log/log_compare.c: Likewise.
	* db2/log/log_put.c: Likewise.
	* db2/log/log_rec.c: Likewise.
	* db2/log/log_archive.c: Likewise.
	* db2/log/log_register.c: Likewise.
	* db2/log/log_auto.c: Likewise.
	* db2/log/log_findckp.c: Likewise.
	* db2/mp/mp_bh.c: Likewise.
	* db2/mp/mp_fget.c: Likewise.
	* db2/mp/mp_fopen.c: Likewise.
	* db2/mp/mp_fput.c: Likewise.
	* db2/mp/mp_fset.c: Likewise.
	* db2/mp/mp_open.c: Likewise.
	* db2/mp/mp_region.c: Likewise.
	* db2/mp/mp_pr.c: Likewise.
	* db2/mp/mp_sync.c: Likewise.
	* db2/mutex/68020.gcc: Likewise.
	* db2/mutex/mutex.c: Likewise.
	* db2/mutex/README: Likewise.
	* db2/mutex/x86.gcc: Likewise.
	* db2/mutex/sparc.gcc: Likewise.
	* db2/mutex/uts4.cc.s: Likewise.
	* db2/mutex/alpha.dec: Likewise.
	* db2/mutex/alpha.gcc: Likewise.
	* db2/mutex/parisc.gcc: Likewise.
	* db2/mutex/parisc.hp: Likewise.
	* db2/os/db_os_abs.c: Likewise.
	* db2/os/db_os_dir.c: Likewise.
	* db2/os/db_os_fid.c: Likewise.
	* db2/os/db_os_lseek.c: Likewise.
	* db2/os/db_os_mmap.c: Likewise.
	* db2/os/db_os_open.c: Likewise.
	* db2/os/db_os_rw.c: Likewise.
	* db2/os/db_os_sleep.c: Likewise.
	* db2/os/db_os_stat.c: Likewise.
	* db2/os/db_os_unlink.c: Likewise.
	* db2/txn/txn.c: Likewise.
	* db2/txn/txn.src: Likewise.
	* db2/txn/txn_rec.c: Likewise.
	* db2/txn/txn_auto.c: Likewise.
	* db2/clib/getlong.c: Likewise.
	* db2/progs/db_archive/db_archive.c: Likewise.
	* db2/progs/db_checkpoint/db_checkpoint.c: Likewise.
	* db2/progs/db_deadlock/db_deadlock.c: Likewise.
	* db2/progs/db_dump/db_dump.c: Likewise.
	* db2/progs/db_dump185/db_dump185.c: Likewise.
	* db2/progs/db_load/db_load.c: Likewise.
	* db2/progs/db_printlog/db_printlog.c: Likewise.
	* db2/progs/db_recover/db_recover.c: Likewise.
	* db2/progs/db_stat/db_stat.c: Likewise.

	* libio/stdio.h [__cplusplus] (__STDIO_INLINE): Define as inline.

	* po/de.po, po/sv.po: Update from 2.0.5 translations.

	* sysdeps/unix/sysv/linux/netinet/tcp.h: Pretty print.

	* sunrpc/rpc/xdr.h (XDR): Don't define argument of x_destroy callback
	as const.
	* sunrpc/xdr_mem.c (xdrmem_destroy): Don't define argument as const.
	* sunrpx/xdr_rec.c (xdrrec_destroy): Likewise.
	* sunrpx/xdr_stdio.c (xdrstdio_destroy): Likewise.

1997-08-27 18:47  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/unix/sysv/linux/if_index.c: Include <errno.h>.
	Reported by Benjamin Kosnik <bkoz@cygnus.com>.

1997-08-27 02:27  Roland McGrath  <roland@baalperazim.frob.com>

	* abi-tags: New file.
	* csu/Makefile (distribute): Remove abi-tag.h.
	($(objpfx)abi-tag.h): New target.
	* Makefile (distribute): Add abi-tags.
	* sysdeps/unix/sysv/linux/abi-tag.h: File removed.
	* sysdeps/mach/hurd/abi-tag.h: File removed.
	* sysdeps/stub/abi-tag.h: File removed.

1997-08-25  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/unix/make-syscalls.sh: Change output so that it
	generates compilation rules only for the currently selected object
	suffixes.

1997-08-25  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* sysdeps/m68k/dl-machine.h (RTLD_START): Switch back to previous
	section to avoid confusing the compiler.
	* sysdeps/alpha/dl-machine.h (RTLD_START): Likewise.
	* sysdeps/i386/dl-machine.h (RTLD_START): Likewise.
	* sysdeps/mips/dl-machine.h (RTLD_START): Likewise.
	* sysdeps/mips/mips64/dl-machine.h (RTLD_START): Likewise.
	* sysdeps/sparc/sparc32/dl-machine.h (RTLD_START): Likewise.

	* sysdeps/m68k/dl-machine.h (elf_machine_load_address): Use a GOT
	relocation instead of a constant to avoid text relocation.
	(ELF_MACHINE_BEFORE_RTLD_RELOC): Removed.
	(RTLD_START): Declare global labels as functions and add size
	directive.

1997-08-25 17:01  Ulrich Drepper  <drepper@cygnus.com>

	* sysdeps/i386/bits/select.h: Correct assembler versions to work even
	for descriptors >= 32.

	* stdlib/alloca.h: Don't define alloca to __alloca since if gcc
	is used __alloca is not defined to __builtin_alloca and so might
	not be available.
	Reported by Uwe Ohse <uwe@ohse.de>.

	* sysdeps/unix/sysv/linux/sys/sysmacros.h: Define macros in a special
	way if gcc is not used and so dev_t is an array.
	Reported by Uwe Ohse <uwe@ohse.de>.

1997-08-23  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* manual/libc.texinfo: Reorder chapters to match logical order.

1997-08-25 12:22  Ulrich Drepper  <drepper@cygnus.com>

	* sunrpc/rpc/xdr.h: Change name of parameters in prototypes of
	xdr_reference, xdrmem_create, and xdrstdio_create because of clash
	with g++ internal symbols.
	Patch by Sudish Joseph <sj@eng.mindspring.net>.

	* elf/dl-deps.c: Implement handling of DT_FILTER.
Diffstat (limited to 'db2/mutex')
-rw-r--r--db2/mutex/68020.gcc19
-rw-r--r--db2/mutex/README105
-rw-r--r--db2/mutex/alpha.dec25
-rw-r--r--db2/mutex/alpha.gcc52
-rw-r--r--db2/mutex/mutex.c280
-rw-r--r--db2/mutex/parisc.gcc40
-rw-r--r--db2/mutex/parisc.hp29
-rw-r--r--db2/mutex/sparc.gcc33
-rw-r--r--db2/mutex/uts4.cc.s21
-rw-r--r--db2/mutex/x86.gcc17
10 files changed, 621 insertions, 0 deletions
diff --git a/db2/mutex/68020.gcc b/db2/mutex/68020.gcc
new file mode 100644
index 0000000000..9d8be641d8
--- /dev/null
+++ b/db2/mutex/68020.gcc
@@ -0,0 +1,19 @@
+/*
+ * @(#)68020.gcc	10.1 (Sleepycat) 4/12/97
+ *
+ * For gcc/68K, 0 is clear, 1 is set.
+ */
+#define TSL_SET(tsl) ({							\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	    asm volatile("tas  %1; \n					\
+			  seq  %0"					\
+		: "=dm" (__r), "=m" (*__l)				\
+		: "1" (*__l)						\
+		);							\
+	__r & 1;							\
+})
+
+#define	TSL_UNSET(tsl)	(*(tsl) = 0)
+#define	TSL_INIT(tsl)	TSL_UNSET(tsl)
+
diff --git a/db2/mutex/README b/db2/mutex/README
new file mode 100644
index 0000000000..30d6b6a7d1
--- /dev/null
+++ b/db2/mutex/README
@@ -0,0 +1,105 @@
+# @(#)README	10.1 (Sleepycat) 4/12/97
+
+Resource locking routines: lock based on a db_mutex_t.  All this gunk
+(including trying to make assembly code portable), is necessary because
+System V semaphores require system calls for uncontested locks and we
+don't want to make two system calls per resource lock.
+
+First, this is how it works.  The db_mutex_t structure contains a resource
+test-and-set lock (tsl), a file offset, a pid for debugging and statistics
+information.
+
+If HAVE_SPINLOCKS is defined (i.e. we know how to do test-and-sets for
+this compiler/architecture combination), we try and lock the resource tsl
+TSL_DEFAULT_SPINS times.  If we can't acquire the lock that way, we use
+a system call to sleep for 10ms, 20ms, 40ms, etc.  (The time is bounded
+at 1 second, just in case.)  Using the timer backoff means that there are
+two assumptions: that locks are held for brief periods (never over system
+calls or I/O) and that locks are not hotly contested.
+
+If HAVE_SPINLOCKS is not defined, i.e. we can't do test-and-sets, we use
+a file descriptor to do byte locking on a file at a specified offset.  In
+this case, ALL of the locking is done in the kernel.  Because file
+descriptors are allocated per process, we have to provide the file
+descriptor as part of the lock/unlock call.  We still have to do timer
+backoff because we need to be able to block ourselves, i.e. the lock
+manager causes processes to wait by having the process acquire a mutex
+and then attempting to re-acquire the mutex.  There's no way to use kernel
+locking to block yourself, i.e. if you hold a lock and attempt to
+re-acquire it, the attempt will succeed.
+
+Next, let's talk about why it doesn't work the way a reasonable person
+would think it should work.
+
+Ideally, we'd have the ability to try to lock the resource tsl, and if
+that fails, increment a counter of waiting processes, then block in the
+kernel until the tsl is released.  The process holding the resource tsl
+would see the wait counter when it went to release the resource tsl, and
+would wake any waiting processes up after releasing the lock.  This would
+actually require both another tsl (call it the mutex tsl) and
+synchronization between the call that blocks in the kernel and the actual
+resource tsl.  The mutex tsl would be used to protect accesses to the
+db_mutex_t itself.  Locking the mutex tsl would be done by a busy loop,
+which is safe because processes would never block holding that tsl (all
+they would do is try to obtain the resource tsl and set/check the wait
+count).  The problem in this model is that the blocking call into the
+kernel requires a blocking semaphore, i.e. one whose normal state is
+locked.
+
+The only portable forms of locking under UNIX are fcntl(2) on a file
+descriptor/offset, and System V semaphores.  Neither of these locking
+methods are sufficient to solve the problem.
+
+The problem with fcntl locking is that only the process that obtained the
+lock can release it.  Remember, we want the normal state of the kernel
+semaphore to be locked.  So, if the creator of the db_mutex_t were to
+initialize the lock to "locked", then a second process locks the resource
+tsl, and then a third process needs to block, waiting for the resource
+tsl, when the second process wants to wake up the third process, it can't
+because it's not the holder of the lock!  For the second process to be
+the holder of the lock, we would have to make a system call per
+uncontested lock, which is what we were trying to get away from in the
+first place.
+
+There are some hybrid schemes, such as signaling the holder of the lock,
+or using a different blocking offset depending on which process is
+holding the lock, but it gets complicated fairly quickly.  I'm open to
+suggestions, but I'm not holding my breath.
+
+Regardless, we use this form of locking when HAVE_SPINLOCKS is not
+defined, (i.e. we're locking in the kernel) because it doesn't have the
+limitations found in System V semaphores, and because the normal state of
+the kernel object in that case is unlocked, so the process releasing the
+lock is also the holder of the lock.
+
+The System V semaphore design has a number of other limitations that make
+it inappropriate for this task.  Namely:
+
+First, the semaphore key name space is separate from the file system name
+space (although there exist methods for using file names to create
+semaphore keys).  If we use a well-known key, there's no reason to believe
+that any particular key will not already be in use, either by another
+instance of the DB application or some other application, in which case
+the DB application will fail.  If we create a key, then we have to use a
+file system name to rendezvous and pass around the key.
+
+Second, System V semaphores traditionally have compile-time, system-wide
+limits on the number of semaphore keys that you can have.  Typically, that
+number is far too low for any practical purpose.  Since the semaphores
+permit more than a single slot per semaphore key, we could try and get
+around that limit by using multiple slots, but that means that the file
+that we're using for rendezvous is going to have to contain slot
+information as well as semaphore key information, and we're going to be
+reading/writing it on every db_mutex_t init or destroy operation.  Anyhow,
+similar compile-time, system-wide limits on the numbers of slots per
+semaphore key kick in, and you're right back where you started.
+
+My fantasy is that once POSIX.1 standard mutexes are in wide-spread use,
+we can switch to them.  My guess is that it won't happen, because the
+POSIX semaphores are only required to work for threads within a process,
+and not independent processes.
+
+Note: there are races in the statistics code, but since it's just that,
+I didn't bother fixing them.  (The fix requires a mutex tsl, so, when/if
+this code is fixed to do rational locking (see above), then change the
+statistics update code to acquire/release the mutex tsl.
diff --git a/db2/mutex/alpha.dec b/db2/mutex/alpha.dec
new file mode 100644
index 0000000000..83ed371136
--- /dev/null
+++ b/db2/mutex/alpha.dec
@@ -0,0 +1,25 @@
+/*
+ * @(#)alpha.dec	8.3 (Sleepycat Software) 1/18/97
+ *
+ * The DEC C asm acts as a pseudo-call.  The first argument is the assembly
+ * code, and the remaining arguments are assigned as in a procedure call, to
+ * r16, r17, etc. (represented in asm as %a0, %a1, and so forth).
+ *
+ * From: Dave Butenhof.
+ */
+
+#include <c_asm.h>
+
+#define	TSL_SET(tsl)	(asm ("mb;					\
+    10:	ldl_l	%v0,(%a0) ;						\
+	bne	%v0,30f ;						\
+	or	%v0,1,%r1 ;						\
+	stl_c	%r1,(%a0) ;						\
+	beq	%r1,20f ;						\
+	mb	;							\
+	br	%r31,30f ;						\
+    20:	br	%r31,10b ;						\
+    30:	", (tsl)))
+
+THIS WAS NOT CONVERTED TO TAKE A POINTER AS AN ARGUMENT...
+#define	TSL_UNSET(tsl)	(asm ("mb"), *(tsl) = 0)
diff --git a/db2/mutex/alpha.gcc b/db2/mutex/alpha.gcc
new file mode 100644
index 0000000000..247d04cf31
--- /dev/null
+++ b/db2/mutex/alpha.gcc
@@ -0,0 +1,52 @@
+/*
+ * @(#)alpha.gcc	10.1 (Sleepycat) 4/12/97
+ *
+ * The code appearing below is taken from Richard L. Sites, ed.  "Alpha
+ * Architecture Reference Manual", Digital Press, 1992, page 5-7 and 5-8.
+ * There are 2 modifications:
+ *
+ * 1. The jump from blbs __r1,30f to !__r1, which is dictated by the way the
+ * TSL_SET macro is used.  The code suggested in Sites includes the main loop
+ * of the spin lock, whereas in this code the rest the loop is specified in C.
+ * The generated code might be suboptimal if the compiler generates a forward
+ * branch for the usual case in which the mutex is uncontested.
+ *
+ * 2. At label 20, Sites suggests including code for testing for an excessive
+ * number of _processor_ lock conflicts.  (The seq_c instruction stores its
+ * first argument provided that no other processor has written to a byte range
+ * including its memory-location argument.)  Absent such checking the code
+ * below could conceivably stall silently on a multiprocessor alpha, depending
+ * on how often processor/processor conflicts occur in a particular byte range.
+ *
+ * Note that the mb ("memory-barrier") instruction in TSL_UNSET is critical to
+ * correct operation in a multiprocessor alpha (as is, of course, the mb in
+ * the TSL_SET macro).  Without the mb, changes to shared memory that occurred
+ * inside the critical section (before the TSL_UNSET) might reach shared memory
+ * _after_ the change of tsl to 0, thereby permitting another processor to see
+ * an inconsistent view of the data protected by the mutex.
+ *
+ * For gcc/alpha, 0 is clear, 1 is set.
+ */
+#define TSL_SET(tsl) ({							\
+	register tsl_t *__l = (tsl);					\
+	register tsl_t __r1, __r2;					\
+	__asm__ volatile("						\n\
+	   10: ldq_l %0,(%2)						\n\
+	       blbs  %0,30f						\n\
+	       or    %0,1,%1						\n\
+	       stq_c %1,(%2)						\n\
+	       beq   %1,20f						\n\
+	       mb							\n\
+	       br    30f						\n\
+	   20: br    10b						\n\
+	   30: "							\
+	  : "=&r" (__r1), "=&r" (__r2)					\
+	  : "r" (__l));							\
+	!__r1;								\
+})
+
+#define TSL_UNSET(tsl) ({						\
+	register tsl_t *__l = (tsl);					\
+	__asm__ volatile("mb; stq $31,(%0);" : : "r" (__l));		\
+})
+#define	TSL_INIT(tsl)	TSL_UNSET(tsl)
diff --git a/db2/mutex/mutex.c b/db2/mutex/mutex.c
new file mode 100644
index 0000000000..b23f738ad7
--- /dev/null
+++ b/db2/mutex/mutex.c
@@ -0,0 +1,280 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997
+ *	Sleepycat Software.  All rights reserved.
+ */
+
+#include "config.h"
+
+#ifndef lint
+static const char sccsid[] = "@(#)mutex.c	10.22 (Sleepycat) 8/21/97";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#endif
+
+#include "db_int.h"
+#include "common_ext.h"
+
+#ifdef HAVE_SPINLOCKS
+
+#ifdef HAVE_FUNC_AIX
+#define	TSL_INIT(x)
+#define	TSL_SET(x)	(!_check_lock(x, 0, 1))
+#define	TSL_UNSET(x)	_clear_lock(x, 0)
+#endif
+
+#ifdef HAVE_ASSEM_MC68020_GCC
+#include "68020.gcc"
+#endif
+
+#if defined(HAVE_FUNC_MSEM)
+/*
+ * XXX
+ * Should we not use MSEM_IF_NOWAIT and let the system block for us?
+ * I've no idea if this will block all threads in the process or not.
+ */
+#define	TSL_INIT(x)	msem_init(x, MSEM_UNLOCKED)
+#define	TSL_SET(x)	(!msem_lock(x, MSEM_IF_NOWAIT))
+#define	TSL_UNSET(x)	msem_unlock(x, 0)
+#endif
+
+#ifdef HAVE_FUNC_SGI
+#define	TSL_INIT(x)	init_lock(x)
+#define	TSL_SET(x)	(!acquire_lock(x))
+#define	TSL_UNSET(x)	release_lock(x)
+#endif
+
+#ifdef HAVE_FUNC_SOLARIS
+/*
+ * Semaphore calls don't work on Solaris 5.5.
+ *
+ * #define	TSL_INIT(x)	sema_init(x, 1, USYNC_PROCESS, NULL)
+ * #define	TSL_SET(x)	(sema_wait(x) == 0)
+ * #define	TSL_UNSET(x)	sema_post(x)
+ */
+#define	TSL_INIT(x)
+#define	TSL_SET(x)	(_lock_try(x))
+#define	TSL_UNSET(x)	_lock_clear(x)
+#endif
+
+#ifdef HAVE_ASSEM_SPARC_GCC
+#include "sparc.gcc"
+#endif
+
+#ifdef HAVE_ASSEM_UTS4_CC
+#define TSL_INIT(x)
+#define TSL_SET(x)	(!uts_lock(x, 1))
+#define TSL_UNSET(x)	(*(x) = 0)
+#endif
+
+#ifdef HAVE_ASSEM_X86_GCC
+#include "x86.gcc"
+#endif
+
+#if defined(_WIN32)
+/* DBDB this needs to be byte-aligned!! */
+#define	TSL_INIT(tsl)
+#define	TSL_SET(tsl)	(!InterlockedExchange((PLONG)tsl, 1))
+#define	TSL_UNSET(tsl)	(*(tsl) = 0)
+#endif
+
+#ifdef macintosh
+/* Mac spinlocks are simple because we cannot possibly be preempted. */
+#define	TSL_INIT(tsl)
+#define	TSL_SET(tsl)	(*(tsl) = 1)
+#define	TSL_UNSET(tsl)	(*(tsl) = 0)
+#endif
+
+#endif /* HAVE_SPINLOCKS */
+
+#ifdef	MORE_THAN_ONE_PROCESSOR
+#define	TSL_DEFAULT_SPINS	5	/* Default spins before block. */
+#else
+#define	TSL_DEFAULT_SPINS	1	/* Default spins before block. */
+#endif
+
+/*
+ * __db_mutex_init --
+ *	Initialize a DB mutex structure.
+ *
+ * PUBLIC: void __db_mutex_init __P((db_mutex_t *, off_t));
+ */
+void
+__db_mutex_init(mp, off)
+	db_mutex_t *mp;
+	off_t off;
+{
+#ifdef DEBUG
+	if ((ALIGNTYPE)mp & (MUTEX_ALIGNMENT - 1)) {
+		(void)fprintf(stderr,
+		    "MUTEX ERROR: mutex NOT %d-byte aligned!\n",
+		    MUTEX_ALIGNMENT);
+		abort();
+	}
+#endif
+	memset(mp, 0, sizeof(db_mutex_t));
+
+#ifdef HAVE_SPINLOCKS
+	TSL_INIT(&mp->tsl_resource);
+#else
+	mp->off = off;
+#endif
+}
+
+#define	MS(n)		((n) * 1000)	/* Milliseconds to micro-seconds. */
+#define	SECOND		(MS(1000))	/* A second's worth of micro-seconds. */
+
+/*
+ * __db_mutex_lock
+ *	Lock on a mutex, logically blocking if necessary.
+ *
+ * PUBLIC: int __db_mutex_lock __P((db_mutex_t *, int, int (*)(void)));
+ */
+int
+__db_mutex_lock(mp, fd, yield)
+	db_mutex_t *mp;
+	int fd;
+	int (*yield) __P((void));
+{
+	u_long usecs;
+
+#ifdef HAVE_SPINLOCKS
+	int nspins;
+
+	for (usecs = MS(10);;) {
+		/*
+		 * Try and acquire the uncontested resource lock for
+		 * TSL_DEFAULT_SPINS.
+		 */
+		for (nspins = TSL_DEFAULT_SPINS; nspins > 0; --nspins)
+			if (TSL_SET(&mp->tsl_resource)) {
+#ifdef DEBUG
+				if (mp->pid != 0) {
+					(void)fprintf(stderr,
+		    "MUTEX ERROR: __db_mutex_lock: lock currently locked\n");
+					abort();
+				}
+				mp->pid = getpid();
+#endif
+#ifdef MUTEX_STATISTICS
+				if (usecs == MS(10))
+					++mp->mutex_set_nowait;
+				else
+					++mp->mutex_set_wait;
+#endif
+				return (0);
+			}
+
+		/* Yield the processor; wait 10ms initially, up to 1 second. */
+		if (yield == NULL || yield() != 0) {
+			(void)__db_sleep(0, usecs);
+			if ((usecs <<= 1) > SECOND)
+				usecs = SECOND;
+		}
+	}
+	/* NOTREACHED */
+
+#else /* !HAVE_SPINLOCKS */
+	struct flock k_lock;
+	pid_t mypid;
+	int locked;
+
+	/* Initialize the lock. */
+	k_lock.l_whence = SEEK_SET;
+	k_lock.l_start = mp->off;
+	k_lock.l_len = 1;
+
+	for (locked = 0, mypid = getpid();;) {
+		/*
+		 * Wait for the lock to become available; wait 10ms initially,
+		 * up to 1 second.
+		 */
+		for (usecs = MS(10); mp->pid != 0;)
+			if (yield == NULL || yield() != 0) {
+				(void)__db_sleep(0, usecs);
+				if ((usecs <<= 1) > SECOND)
+					usecs = SECOND;
+			}
+
+		/* Acquire an exclusive kernel lock. */
+		k_lock.l_type = F_WRLCK;
+		if (fcntl(fd, F_SETLKW, &k_lock))
+			return (1);
+
+		/* If the resource tsl is still available, it's ours. */
+		if (mp->pid == 0) {
+			locked = 1;
+			mp->pid = mypid;
+		}
+
+		/* Release the kernel lock. */
+		k_lock.l_type = F_UNLCK;
+		if (fcntl(fd, F_SETLK, &k_lock))
+			return (1);
+
+		/*
+		 * If we got the resource tsl we're done.
+		 *
+		 * !!!
+		 * We can't check to see if the lock is ours, because we may
+		 * be trying to block ourselves in the lock manager, and so
+		 * the holder of the lock that's preventing us from getting
+		 * the lock may be us!  (Seriously.)
+		 */
+		if (locked)
+			break;
+	}
+
+#ifdef MUTEX_STATISTICS
+	++mp->mutex_set_wait;
+#endif
+	return (0);
+#endif /* !HAVE_SPINLOCKS */
+}
+
+/*
+ * __db_mutex_unlock --
+ *	Release a lock.
+ *
+ * PUBLIC: int __db_mutex_unlock __P((db_mutex_t *, int));
+ */
+int
+__db_mutex_unlock(mp, fd)
+	db_mutex_t *mp;
+	int fd;
+{
+#ifdef DEBUG
+	if (mp->pid == 0) {
+		(void)fprintf(stderr,
+	    "MUTEX ERROR: __db_mutex_unlock: lock already unlocked\n");
+		abort();
+	}
+#endif
+
+#ifdef HAVE_SPINLOCKS
+#ifdef DEBUG
+	mp->pid = 0;
+#endif
+
+	/* Release the resource tsl. */
+	TSL_UNSET(&mp->tsl_resource);
+#else
+	/*
+	 * Release the resource tsl.  We don't have to acquire any locks
+	 * because processes trying to acquire the lock are checking for
+	 * a pid of 0, not a specific value.
+	 */
+	mp->pid = 0;
+#endif
+	return (0);
+}
diff --git a/db2/mutex/parisc.gcc b/db2/mutex/parisc.gcc
new file mode 100644
index 0000000000..e15f6f2dba
--- /dev/null
+++ b/db2/mutex/parisc.gcc
@@ -0,0 +1,40 @@
+/* 
+ * @(#)parisc.gcc	8.5 (Sleepycat) 1/18/97
+ *
+ * Copyright (c) 1996-1997, The University of Utah and the Computer Systems
+ * Laboratory at the University of Utah (CSL).  All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the Computer
+ * Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ */
+
+/*
+ * The PA-RISC has a "load and clear" instead of a "test and set" instruction.
+ * The 32-bit word used by that instruction must be 16-byte aligned hence we
+ * allocate 16 bytes for a tsl_t and use the word that is properly aligned.
+ * We could use the "aligned" attribute in GCC but that doesn't work for stack
+ * variables.
+ */
+#define	TSL_SET(tsl) ({							\
+	int *__l = (int *)(((int)(tsl)+15)&~15);			\
+	int __r;							\
+	asm volatile("ldcws 0(%1),%0" : "=r" (__r) : "r" (__l));	\
+	__r & 1;							\
+})
+
+#define	TSL_UNSET(tsl) ({						\
+	int *__l = (int *)(((int)(tsl)+15)&~15);			\
+	*__l = -1;							\
+})
diff --git a/db2/mutex/parisc.hp b/db2/mutex/parisc.hp
new file mode 100644
index 0000000000..d10807b7f1
--- /dev/null
+++ b/db2/mutex/parisc.hp
@@ -0,0 +1,29 @@
+/* 
+ * @(#)parisc.hp	8.5 (Sleepycat) 1/18/97
+ *
+ * Copyright (c) 1996-1997, The University of Utah and the Computer Systems
+ * Laboratory at the University of Utah (CSL).  All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the Computer
+ * Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ */
+
+/*
+ * The PA-RISC has a "load and clear" instead of a "test and set" instruction.
+ * The 32-bit word used by that instruction must be 16-byte aligned hence we
+ * allocate 16 bytes for a tsl_t and use the word that is properly aligned.
+ */
+#define	TSL_SET(tsl)	tsl_set(tsl)
+#define	TSL_UNSET(tsl)	tsl_unset(tsl)
diff --git a/db2/mutex/sparc.gcc b/db2/mutex/sparc.gcc
new file mode 100644
index 0000000000..8445a0629b
--- /dev/null
+++ b/db2/mutex/sparc.gcc
@@ -0,0 +1,33 @@
+/*
+ * @(#)sparc.gcc	10.1 (Sleepycat) 4/12/97
+ *
+ * The ldstub instruction takes the location specified by its first argument
+ * (a register containing a memory address) and loads its contents into its
+ * second argument (a register) and atomically sets the contents the location
+ * specified by its first argument to a byte of 1s.  (The value in the second
+ * argument is never read, but only overwritten.)
+ *
+ * The membar instructions are needed to ensure that writes to the lock are
+ * correctly ordered with writes that occur later in the instruction stream.
+ *
+ * For gcc/sparc, 0 is clear, 1 is set.
+ */
+
+#if defined(__sparcv9__)
+Does the following code need membar instructions for V9 processors?
+#endif
+
+#define	TSL_SET(tsl) ({							\
+	register tsl_t *__l = (tsl);					\
+	register tsl_t __r;						\
+	__asm__ volatile						\
+	    ("ldstub [%1],%0"						\
+	    : "=r"( __r) : "r" (__l));					\
+	!__r;								\
+})
+
+#define	TSL_UNSET(tsl) ({						\
+         register tsl_t *__l = (tsl);					\
+        __asm__ volatile ("stb %%g0,[%0]" : : "r" (__l));		\
+})
+#define	TSL_INIT(tsl)	TSL_UNSET(tsl)
diff --git a/db2/mutex/uts4.cc.s b/db2/mutex/uts4.cc.s
new file mode 100644
index 0000000000..ee5f4143bd
--- /dev/null
+++ b/db2/mutex/uts4.cc.s
@@ -0,0 +1,21 @@
+ /
+ / int uts_lock ( int *p, int i );
+ /             Update the lock word pointed to by p with the
+ /             value i, using compare-and-swap.
+ /             Returns 0 if update was successful.
+ /             Returns 1 if update failed.
+ /
+         entry   uts_lock
+ uts_lock:
+         using   .,r15
+         st      r2,8(sp)        / Save R2
+         l       r2,64+0(sp)     / R2 -> word to update
+         slr     r0, r0          / R0 = current lock value must be 0
+         l       r1,64+4(sp)     / R1 = new lock value
+         cs      r0,r1,0(r2)     / Try the update ...
+         be      x               /  ... Success.  Return 0
+         la      r0,1            /  ... Failure.  Return 1
+ x:                              /
+         l       r2,8(sp)        / Restore R2
+         b       2(,r14)         / Return to caller
+         drop    r15
diff --git a/db2/mutex/x86.gcc b/db2/mutex/x86.gcc
new file mode 100644
index 0000000000..886a6811a2
--- /dev/null
+++ b/db2/mutex/x86.gcc
@@ -0,0 +1,17 @@
+/*
+ * @(#)x86.gcc	10.2 (Sleepycat) 6/21/97
+ *
+ * For gcc/x86, 0 is clear, 1 is set.
+ */
+#define	TSL_SET(tsl) ({							\
+	register tsl_t *__l = (tsl);					\
+	int __r;							\
+	asm volatile("movl $1,%%eax; xchgb %1,%%al; xorl $1,%%eax"	\
+	    : "=&a" (__r), "=m" (*__l)					\
+	    : "1" (*__l)						\
+	    );								\
+	__r & 1;							\
+})
+
+#define	TSL_UNSET(tsl)	(*(tsl) = 0)
+#define	TSL_INIT(tsl)	TSL_UNSET(tsl)