cef5dfd75a
(user_info::version): Make LONG to accommodate spinlock use. (user_info::create): New static function renamed from user_info_create. (user_info::initialize): New private function renamed from user_info_initialize. (SHARED_VERSION): Delete. (SHARED_VERSION_MAGIC): Ditto. (USER_VERSION_MAGIC): Ditto. (SHARED_INFO_CB): Ditto. (USER_VERSION): Ditto. (USER_VERSION_MAGIC): Ditto. (CURR_SHARED_MAGIC): Update. (CURR_USER_MAGIC): Ditto. (shared_info::version): Make LONG to accommodate spinlock use. (shared_info::create): New static function mirroring user_info::create. (dll_crt0_1): Accommodate change to user_info::initialize. * spinlock.h (spinlock::setto): New variable member. (spinlock::done): New function. (spinlock::spinlock): Generalize to allow arbitrary values and timeouts. Call done() when lock is not needed. * ntdll.h: Make multiple-inclusion safe. (NtQuerySystemTime): Declare. * shared.cc (installation_root_inited): Rename from shared_mem_inited. (init_installation_root): Make inline. Use a spinlock to ensure that this is initialized only once per session. (user_info::initialize): Rename from user_shared_initialize. Protect with spinlock on sversion and remove other spinlock-like things. Remove reference to user_shared since it is now implicit. Refer to spinlock version of multiple_cygwin_problem to ensure that any spinlock is released. (user_info::create): Rename from user_shared_create. Accommodate change from user_shared_initialize to user_info::initialize. (shared_info::create): New inline function. (shared_info::initialize): Protect with spinlock on sversion. Move heap_init back under specific control of shared_info spinlock. Remove reference to SHARED_INFO_CB and just use sizeof(*this). (memory_init): Move all locking into respective functions where it is needed. Accommodate name changes. Remove call to heap_init(). * syscalls.cc (seteuid32): Accommodate name change to user_info::create(). * mount.cc (mount_info::create_root_entry): Report on errors from add_item since they should be nonexistent. (mount_info::init): Don't initialize nmounts. It should already be zero. Give more verbose error when root_idx < 0. Implicitly use this pointer rather than explicitly referencing mount_table->. (mount_info::add_item): Minor whitespace fix.
81 lines
2.3 KiB
C++
81 lines
2.3 KiB
C++
/* spinlock.h: Header file for cygwin time-sensitive synchronization primitive.
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Copyright 2010 Red Hat, Inc.
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#ifndef _SPINLOCK_H
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#define _SPINLOCK_H
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#include "ntdll.h"
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#define SPINLOCK_WAIT (15000LL * 10000LL)
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class spinlock
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{
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LONG *locker;
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LONG val;
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LONG setto;
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void done (LONG what)
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{
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if (locker)
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{
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InterlockedExchange (locker, what);
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locker = NULL;
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}
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}
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long long time ()
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{
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LARGE_INTEGER t;
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if (NtQuerySystemTime (&t) == STATUS_SUCCESS)
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return get_ll (t);
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return 0LL;
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}
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public:
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spinlock (LONG& locktest, LONG wanted_val = 1, LONGLONG timeout = SPINLOCK_WAIT):
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locker (&locktest), setto (wanted_val)
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{
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/* Quick test to see if we're already initialized */
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if ((val = locktest) == wanted_val)
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locker = NULL;
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/* Slightly less quick test to see if we are the first cygwin process */
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else if ((val = InterlockedExchange (locker, -1)) == 0)
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/* We're armed and dangerous */;
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else if (val == wanted_val)
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done (val); /* This was initialized while we weren't looking */
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else
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{
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long long then = time ();
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/* Loop waiting for some other process to set locktest to something
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other than -1, indicating that initialization has finished. Or,
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wait a default of 15 seconds for that to happen and, if it doesn't
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just grab the lock ourselves. */
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while ((val = InterlockedExchange (locker, -1)) == -1
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&& (time () - then) < timeout)
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yield ();
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/* Reset the lock back to wanted_value under the assumption that is
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what caused the above loop to kick out. */
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if (val == -1)
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val = 0; /* Timed out. We'll initialize things ourselves. */
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else
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done (val); /* Put back whatever was there before, assuming that
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it is actually wanted_val. */
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}
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}
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~spinlock () {done (setto);}
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operator LONG () const {return val;}
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/* FIXME: This should be handled in a more general fashion, probably by
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establishing a linked list of spinlocks which are freed on process exit. */
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void multiple_cygwin_problem (const char *w, unsigned m, unsigned v)
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{
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done (val);
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::multiple_cygwin_problem (w, m, v);
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}
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};
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#endif /*_SPINLOCK_H*/
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