From 027491f6af1ca919f9c1d20995e3e150e03bc978 Mon Sep 17 00:00:00 2001 From: Alexandre Julliard Date: Thu, 18 Jan 2007 12:18:29 +0100 Subject: [PATCH] ntdll: Avoid heap allocation in fd cache. Fixed a couple of races. --- dlls/ntdll/file.c | 6 +++- dlls/ntdll/om.c | 9 +++-- dlls/ntdll/server.c | 85 +++++++++++++++++++++------------------------ 3 files changed, 52 insertions(+), 48 deletions(-) diff --git a/dlls/ntdll/file.c b/dlls/ntdll/file.c index 543fcfb8747..a79d227f5b6 100644 --- a/dlls/ntdll/file.c +++ b/dlls/ntdll/file.c @@ -1107,7 +1107,11 @@ NTSTATUS WINAPI NtFsControlFile(HANDLE handle, HANDLE event, PIO_APC_ROUTINE apc { req->handle = handle; io->u.Status = wine_server_call(req); - if (!io->u.Status) server_remove_fd_from_cache( handle ); + if (!io->u.Status) + { + int fd = server_remove_fd_from_cache( handle ); + if (fd != -1) close( fd ); + } } SERVER_END_REQ; break; diff --git a/dlls/ntdll/om.c b/dlls/ntdll/om.c index af03e7d7d25..56612dca323 100644 --- a/dlls/ntdll/om.c +++ b/dlls/ntdll/om.c @@ -313,7 +313,10 @@ NTSTATUS WINAPI NtDuplicateObject( HANDLE source_process, HANDLE source, { if (dest) *dest = reply->handle; if (reply->closed) - server_remove_fd_from_cache( source ); + { + int fd = server_remove_fd_from_cache( source ); + if (fd != -1) close( fd ); + } else if (options & DUPLICATE_CLOSE_SOURCE) WARN( "failed to close handle %p in process %p\n", source, source_process ); } @@ -337,13 +340,15 @@ NTSTATUS WINAPI NtDuplicateObject( HANDLE source_process, HANDLE source, NTSTATUS WINAPI NtClose( HANDLE Handle ) { NTSTATUS ret; + int fd = server_remove_fd_from_cache( Handle ); + SERVER_START_REQ( close_handle ) { req->handle = Handle; ret = wine_server_call( req ); - if (!ret) server_remove_fd_from_cache( Handle ); } SERVER_END_REQ; + if (fd != -1) close( fd ); return ret; } diff --git a/dlls/ntdll/server.c b/dlls/ntdll/server.c index a333082011f..6d8c24e329d 100644 --- a/dlls/ntdll/server.c +++ b/dlls/ntdll/server.c @@ -458,10 +458,8 @@ static int receive_fd( obj_handle_t *handle ) } -inline static unsigned int handle_to_index( obj_handle_t handle ) -{ - return ((unsigned long)handle >> 2) - 1; -} +/***********************************************************************/ +/* fd cache support */ struct fd_cache_entry { @@ -469,8 +467,19 @@ struct fd_cache_entry enum server_fd_type type; }; -static struct fd_cache_entry *fd_cache; -static unsigned int fd_cache_size; +#define FD_CACHE_BLOCK_SIZE (65536 / sizeof(struct fd_cache_entry)) +#define FD_CACHE_ENTRIES 128 + +static struct fd_cache_entry *fd_cache[FD_CACHE_ENTRIES]; +static struct fd_cache_entry fd_cache_initial_block[FD_CACHE_BLOCK_SIZE]; + +inline static unsigned int handle_to_index( obj_handle_t handle, unsigned int *entry ) +{ + unsigned long idx = ((unsigned long)handle >> 2) - 1; + *entry = idx / FD_CACHE_BLOCK_SIZE; + return idx % FD_CACHE_BLOCK_SIZE; +} + /*********************************************************************** * add_fd_to_cache @@ -479,35 +488,31 @@ static unsigned int fd_cache_size; */ static int add_fd_to_cache( obj_handle_t handle, int fd, enum server_fd_type type ) { - unsigned int idx = handle_to_index( handle ); + unsigned int entry, idx = handle_to_index( handle, &entry ); + int prev_fd; - if (idx >= fd_cache_size) + if (entry >= FD_CACHE_ENTRIES) { - unsigned int i, size = max( 32, fd_cache_size * 2 ); - struct fd_cache_entry *new_cache; + FIXME( "too many allocated handles, not caching %p\n", handle ); + return 0; + } - if (size <= idx) size = idx + 1; - if (fd_cache) - new_cache = RtlReAllocateHeap( GetProcessHeap(), 0, fd_cache, size*sizeof(fd_cache[0]) ); + if (!fd_cache[entry]) /* do we need to allocate a new block of entries? */ + { + if (!entry) fd_cache[0] = fd_cache_initial_block; else - new_cache = RtlAllocateHeap( GetProcessHeap(), 0, size*sizeof(fd_cache[0]) ); - - if (new_cache) { - for (i = fd_cache_size; i < size; i++) new_cache[i].fd = -1; - fd_cache = new_cache; - fd_cache_size = size; + void *ptr = wine_anon_mmap( NULL, FD_CACHE_BLOCK_SIZE * sizeof(struct fd_cache_entry), + PROT_READ | PROT_WRITE, 0 ); + if (ptr == MAP_FAILED) return 0; + fd_cache[entry] = ptr; } } - if (idx < fd_cache_size) - { - assert( fd_cache[idx].fd == -1 ); - fd_cache[idx].fd = fd; - fd_cache[idx].type = type; - TRACE("added %p (%d) type %d to cache\n", handle, fd, type ); - return 1; - } - return 0; + /* store fd+1 so that 0 can be used as the unset value */ + prev_fd = interlocked_xchg( &fd_cache[entry][idx].fd, fd + 1 ) - 1; + fd_cache[entry][idx].type = type; + if (prev_fd != -1) close( prev_fd ); + return 1; } @@ -518,13 +523,13 @@ static int add_fd_to_cache( obj_handle_t handle, int fd, enum server_fd_type typ */ static inline int get_cached_fd( obj_handle_t handle, enum server_fd_type *type ) { - unsigned int idx = handle_to_index( handle ); + unsigned int entry, idx = handle_to_index( handle, &entry ); int fd = -1; - if (idx < fd_cache_size) + if (entry < FD_CACHE_ENTRIES && fd_cache[entry]) { - fd = fd_cache[idx].fd; - if (type) *type = fd_cache[idx].type; + fd = fd_cache[entry][idx].fd - 1; + if (type) *type = fd_cache[entry][idx].type; } return fd; } @@ -535,22 +540,12 @@ static inline int get_cached_fd( obj_handle_t handle, enum server_fd_type *type */ int server_remove_fd_from_cache( obj_handle_t handle ) { - unsigned int idx = handle_to_index( handle ); + unsigned int entry, idx = handle_to_index( handle, &entry ); int fd = -1; - RtlEnterCriticalSection( &fd_cache_section ); - if (idx < fd_cache_size) - { - fd = fd_cache[idx].fd; - fd_cache[idx].fd = -1; - } - RtlLeaveCriticalSection( &fd_cache_section ); + if (entry < FD_CACHE_ENTRIES && fd_cache[entry]) + fd = interlocked_xchg( &fd_cache[entry][idx].fd, 0 ) - 1; - if (fd != -1) - { - close( fd ); - TRACE("removed %p (%d) from cache\n", handle, fd ); - } return fd; }