From 2a0ba856de23293e7d82ca43cdd1d51d2cee82a7 Mon Sep 17 00:00:00 2001 From: Ian Lynagh Date: Wed, 26 Oct 2011 23:27:17 +0100 Subject: [PATCH] Stop enforcing single-writer/multi-reader file access --- includes/Rts.h | 1 - includes/rts/FileLock.h | 24 -------- rts/Linker.c | 2 - rts/RtsStartup.c | 11 ---- rts/posix/FileLock.c | 145 ----------------------------------------------- 5 files changed, 0 insertions(+), 183 deletions(-) delete mode 100644 includes/rts/FileLock.h delete mode 100644 rts/posix/FileLock.c diff --git a/includes/Rts.h b/includes/Rts.h index 91ec76d..dadd526 100644 --- a/includes/Rts.h +++ b/includes/Rts.h @@ -202,7 +202,6 @@ void _assertFail(const char *filename, unsigned int linenum) #include "rts/Hpc.h" #include "rts/Flags.h" #include "rts/Adjustor.h" -#include "rts/FileLock.h" #include "rts/Globals.h" #include "rts/IOManager.h" #include "rts/Linker.h" diff --git a/includes/rts/FileLock.h b/includes/rts/FileLock.h deleted file mode 100644 index a7d8d3c..0000000 --- a/includes/rts/FileLock.h +++ /dev/null @@ -1,24 +0,0 @@ -/* ----------------------------------------------------------------------------- - * - * (c) The GHC Team, 2007-2009 - * - * File locking support as required by Haskell - * - * Do not #include this file directly: #include "Rts.h" instead. - * - * To understand the structure of the RTS headers, see the wiki: - * http://hackage.haskell.org/trac/ghc/wiki/Commentary/SourceTree/Includes - * - * ---------------------------------------------------------------------------*/ - -#ifndef RTS_FILELOCK_H -#define RTS_FILELOCK_H - -#ifdef HAVE_SYS_TYPES_H -#include -#endif - -int lockFile(int fd, dev_t dev, ino_t ino, int for_writing); -int unlockFile(int fd); - -#endif /* RTS_FILELOCK_H */ diff --git a/rts/Linker.c b/rts/Linker.c index f5b90d4..acf1336 100644 --- a/rts/Linker.c +++ b/rts/Linker.c @@ -269,8 +269,6 @@ typedef struct _RtsSymbolVal { SymI_HasProto(__hscore_get_saved_termios) \ SymI_HasProto(__hscore_set_saved_termios) \ SymI_HasProto(shutdownHaskellAndSignal) \ - SymI_HasProto(lockFile) \ - SymI_HasProto(unlockFile) \ SymI_HasProto(signal_handlers) \ SymI_HasProto(stg_sig_install) \ SymI_HasProto(rtsTimerSignal) \ diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c index dc62143..d0bc96d 100644 --- a/rts/RtsStartup.c +++ b/rts/RtsStartup.c @@ -52,7 +52,6 @@ void exitLinker( void ); // there is no Linker.h file to include #if !defined(mingw32_HOST_OS) #include "posix/TTY.h" -#include "posix/FileLock.h" #endif #ifdef HAVE_UNISTD_H @@ -189,11 +188,6 @@ hs_init(int *argc, char **argv[]) /* initialise the shared Typeable store */ initGlobalStore(); - /* initialise file locking, if necessary */ -#if !defined(mingw32_HOST_OS) - initFileLocking(); -#endif - #if defined(DEBUG) /* initialise thread label table (tso->char*) */ initThreadLabelTable(); @@ -348,11 +342,6 @@ hs_exit_(rtsBool wait_foreign) /* free linker data */ exitLinker(); - /* free file locking tables, if necessary */ -#if !defined(mingw32_HOST_OS) - freeFileLocking(); -#endif - /* free the stable pointer table */ exitStablePtrTable(); diff --git a/rts/posix/FileLock.c b/rts/posix/FileLock.c deleted file mode 100644 index cb36366..0000000 --- a/rts/posix/FileLock.c +++ /dev/null @@ -1,145 +0,0 @@ -/* ----------------------------------------------------------------------------- - * - * (c) The GHC Team, 2007 - * - * File locking support as required by Haskell - * - * ---------------------------------------------------------------------------*/ - -#include "PosixSource.h" -#include "Rts.h" - -#include "FileLock.h" -#include "Hash.h" -#include "RtsUtils.h" - -#include -#include -#include -#include - -typedef struct { - dev_t device; - ino_t inode; - int readers; // >0 : readers, <0 : writers -} Lock; - -// Two hash tables. The first maps objects (device/inode pairs) to -// Lock objects containing the number of active readers or writers. The -// second maps file descriptors to lock objects, so that we can unlock -// by FD without needing to fstat() again. -static HashTable *obj_hash; -static HashTable *fd_hash; - -#ifdef THREADED_RTS -static Mutex file_lock_mutex; -#endif - -static int cmpLocks(StgWord w1, StgWord w2) -{ - Lock *l1 = (Lock *)w1; - Lock *l2 = (Lock *)w2; - return (l1->device == l2->device && l1->inode == l2->inode); -} - -static int hashLock(HashTable *table, StgWord w) -{ - Lock *l = (Lock *)w; - // Just xor the dev_t with the ino_t, hope this is good enough. - return hashWord(table, (StgWord)l->inode ^ (StgWord)l->device); -} - -void -initFileLocking(void) -{ - obj_hash = allocHashTable_(hashLock, cmpLocks); - fd_hash = allocHashTable(); /* ordinary word-based table */ -#ifdef THREADED_RTS - initMutex(&file_lock_mutex); -#endif -} - -static void -freeLock(void *lock) -{ - stgFree(lock); -} - -void -freeFileLocking(void) -{ - freeHashTable(obj_hash, freeLock); - freeHashTable(fd_hash, NULL); -#ifdef THREADED_RTS - closeMutex(&file_lock_mutex); -#endif -} - -int -lockFile(int fd, dev_t dev, ino_t ino, int for_writing) -{ - Lock key, *lock; - - ACQUIRE_LOCK(&file_lock_mutex); - - key.device = dev; - key.inode = ino; - - lock = lookupHashTable(obj_hash, (StgWord)&key); - - if (lock == NULL) - { - lock = stgMallocBytes(sizeof(Lock), "lockFile"); - lock->device = dev; - lock->inode = ino; - lock->readers = for_writing ? -1 : 1; - insertHashTable(obj_hash, (StgWord)lock, (void *)lock); - insertHashTable(fd_hash, fd, lock); - RELEASE_LOCK(&file_lock_mutex); - return 0; - } - else - { - // single-writer/multi-reader locking: - if (for_writing || lock->readers < 0) { - RELEASE_LOCK(&file_lock_mutex); - return -1; - } - insertHashTable(fd_hash, fd, lock); - lock->readers++; - RELEASE_LOCK(&file_lock_mutex); - return 0; - } -} - -int -unlockFile(int fd) -{ - Lock *lock; - - ACQUIRE_LOCK(&file_lock_mutex); - - lock = lookupHashTable(fd_hash, fd); - if (lock == NULL) { - // errorBelch("unlockFile: fd %d not found", fd); - // This is normal: we didn't know when calling unlockFile - // whether this FD referred to a locked file or not. - RELEASE_LOCK(&file_lock_mutex); - return 1; - } - - if (lock->readers < 0) { - lock->readers++; - } else { - lock->readers--; - } - - if (lock->readers == 0) { - removeHashTable(obj_hash, (StgWord)lock, NULL); - stgFree(lock); - } - removeHashTable(fd_hash, fd, NULL); - - RELEASE_LOCK(&file_lock_mutex); - return 0; -} -- 1.7.2.5