7 files changed, 357 insertions, 14 deletions

diff --git a/backends/plugins/elf/elf-loader.cpp b/backends/plugins/elf/elf-loader.cpp
index f7b151ecee..43477e06e2 100644
--- a/backends/plugins/elf/elf-loader.cpp
+++ b/backends/plugins/elf/elf-loader.cpp
@@ -28,6 +28,7 @@
 #if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER)
 
 #include "backends/plugins/elf/elf-loader.h"
+#include "backends/plugins/elf/memory-manager.h"
 
 #include "common/debug.h"
 #include "common/file.h"
@@ -52,7 +53,7 @@ DLObject::DLObject() :
 
 DLObject::~DLObject() {
 	discardSymtab();
-	free(_segment);
+	ELFMemMan.pluginDeallocate(_segment);
 	_segment = 0;
 }
 
@@ -71,7 +72,7 @@ void DLObject::discardSymtab() {
 void DLObject::unload() {
 	discardSymtab();
 
-	free(_segment);
+	ELFMemMan.pluginDeallocate(_segment);
 
 	_segment = 0;
 	_segmentSize = 0;
@@ -165,7 +166,7 @@ bool DLObject::readProgramHeaders(Elf32_Ehdr *ehdr, Elf32_Phdr *phdr, Elf32_Half
 }
 
 bool DLObject::loadSegment(Elf32_Phdr *phdr) {
-	_segment = (byte *)memalign(phdr->p_align, phdr->p_memsz);
+	_segment = (byte *)ELFMemMan.pluginAllocate(phdr->p_align, phdr->p_memsz);
 
 	if (!_segment) {
 		warning("elfloader: Out of memory.");
@@ -222,19 +223,27 @@ Elf32_Shdr * DLObject::loadSectionHeaders(Elf32_Ehdr *ehdr) {
 	return shdr;
 }
 
-int DLObject::loadSymbolTable(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
-	assert(_file);
-
+int DLObject::findSymbolTableSection(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
+	int SymbolTableSection = -1;
+	
 	// Loop over sections, looking for symbol table linked to a string table
 	for (uint32 i = 0; i < ehdr->e_shnum; i++) {
 		if (shdr[i].sh_type == SHT_SYMTAB &&
 				shdr[i].sh_entsize == sizeof(Elf32_Sym) &&
 				shdr[i].sh_link < ehdr->e_shnum &&
-				shdr[shdr[i].sh_link].sh_type == SHT_STRTAB &&
-				_symtab_sect < 0) {
-			_symtab_sect = i;
+				shdr[shdr[i].sh_link].sh_type == SHT_STRTAB) {
+			SymbolTableSection = i;
+			break;
 		}
 	}
+	
+	return SymbolTableSection;
+}
+
+int DLObject::loadSymbolTable(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr) {
+	assert(_file);
+
+	_symtab_sect = findSymbolTableSection(ehdr, shdr);
 
 	// Check for no symbol table
 	if (_symtab_sect < 0) {
@@ -308,6 +317,43 @@ void DLObject::relocateSymbols(ptrdiff_t offset) {
 	}
 }
 
+// Track the size of the plugin through memory manager without loading
+// the plugin into memory. 
+//
+void DLObject::trackSize(const char *path) {
+	
+	_file = Common::FSNode(path).createReadStream();
+	
+	if (!_file) {
+		warning("elfloader: File %s not found.", path);
+		return;
+	}
+
+	Elf32_Ehdr ehdr;
+	Elf32_Phdr phdr;
+
+	if (!readElfHeader(&ehdr))
+		return;
+	
+	ELFMemMan.trackPlugin(true);	// begin tracking the plugin size
+	
+	// Load the segments
+	for (uint32 i = 0; i < ehdr.e_phnum; i++) {	
+		debug(2, "elfloader: Loading segment %d", i);
+
+		if (!readProgramHeaders(&ehdr, &phdr, i))
+			return;
+
+		if (phdr.p_flags & PF_X) {	// check for executable, allocated segment
+			ELFMemMan.trackAlloc(phdr.p_align, phdr.p_memsz);
+		}
+	}
+	
+	ELFMemMan.trackPlugin(false);	// we're done tracking the plugin size
+
+	// No need to track the symbol table sizes -- they get discarded
+}
+
 bool DLObject::load() {
 	Elf32_Ehdr ehdr;
 	Elf32_Phdr phdr;
@@ -315,7 +361,8 @@ bool DLObject::load() {
 	if (readElfHeader(&ehdr) == false)
 		return false;
 
-	for (uint32 i = 0; i < ehdr.e_phnum; i++) {	//Load our segments
+	//Load the segments
+	for (uint32 i = 0; i < ehdr.e_phnum; i++) {	
 		debug(2, "elfloader: Loading segment %d", i);
 
 		if (readProgramHeaders(&ehdr, &phdr, i) == false)
diff --git a/backends/plugins/elf/elf-loader.h b/backends/plugins/elf/elf-loader.h
index 2825cc9d8d..e11aaf1ad0 100644
--- a/backends/plugins/elf/elf-loader.h
+++ b/backends/plugins/elf/elf-loader.h
@@ -67,6 +67,7 @@ protected:
 	bool readProgramHeaders(Elf32_Ehdr *ehdr, Elf32_Phdr *phdr, Elf32_Half num);
 	virtual bool loadSegment(Elf32_Phdr *phdr);
 	Elf32_Shdr *loadSectionHeaders(Elf32_Ehdr *ehdr);
+	int findSymbolTableSection(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr);
 	int loadSymbolTable(Elf32_Ehdr *ehdr, Elf32_Shdr *shdr);
 	bool loadStringTable(Elf32_Shdr *shdr);
 	virtual void relocateSymbols(ptrdiff_t offset);
@@ -90,6 +91,11 @@ public:
 	DLObject();
 	virtual ~DLObject();
 
+	/**
+	 * Test the size of the plugin in memory using the memory manager.
+	 * @param path			Path of file
+	 */
+	void trackSize(const char *path);
 	bool open(const char *path);
 	bool close();
 	void *symbol(const char *name);
diff --git a/backends/plugins/elf/elf-provider.cpp b/backends/plugins/elf/elf-provider.cpp
index b241379934..393010fd6f 100644
--- a/backends/plugins/elf/elf-provider.cpp
+++ b/backends/plugins/elf/elf-provider.cpp
@@ -33,6 +33,7 @@
 
 #include "backends/plugins/elf/elf-provider.h"
 #include "backends/plugins/dynamic-plugin.h"
+#include "backends/plugins/elf/memory-manager.h"
 
 #include "common/debug.h"
 #include "common/fs.h"
@@ -96,6 +97,17 @@ DynamicPlugin::VoidFunc ELFPlugin::findSymbol(const char *symbol) {
 	return tmp;
 }
 
+ /**
+  * Test the size of the plugin.
+  */
+void ELFPlugin::trackSize() {
+	// All we need to do is create our object, track its size, then delete it
+	DLObject *obj = makeDLObject();
+	
+	obj->trackSize(_filename.c_str());
+	delete obj;
+}
+
 bool ELFPlugin::loadPlugin() {
 	assert(!_dlHandle);
 
@@ -162,6 +174,30 @@ void ELFPlugin::unloadPlugin() {
 	}
 }
 
+ /**
+  * We override this function in FilePluginProvider to allow the single
+  * plugin method to create a non-fragmenting memory allocation. We take
+  * the plugins found and tell the memory manager to allocate space for
+  * them.
+  */
+PluginList ELFPluginProvider::getPlugins() {
+	PluginList pl = FilePluginProvider::getPlugins();
+
+#if defined(ONE_PLUGIN_AT_A_TIME) && !defined(ELF_NO_MEM_MANAGER) 	
+	// This static downcast is safe because all of the plugins must
+	// be ELF plugins
+	for (PluginList::iterator p = pl.begin(); p != pl.end(); ++p) {
+		(static_cast<ELFPlugin *>(*p))->trackSize();
+	}
+
+	// The Memory Manager should now allocate space based on the information
+	// it collected
+	ELFMemMan.allocateHeap();
+#endif	
+	
+	return pl;
+}
+
 bool ELFPluginProvider::isPluginFilename(const Common::FSNode &node) const {
 	// Check the plugin suffix
 	Common::String filename = node.getName();
diff --git a/backends/plugins/elf/elf-provider.h b/backends/plugins/elf/elf-provider.h
index 4d05c0956b..fe8346f95e 100644
--- a/backends/plugins/elf/elf-provider.h
+++ b/backends/plugins/elf/elf-provider.h
@@ -67,8 +67,9 @@ public:
 
 	virtual DLObject *makeDLObject() = 0;
 
-	bool loadPlugin();
-	void unloadPlugin();
+	virtual bool loadPlugin();
+	virtual void unloadPlugin();
+	void trackSize();
 };
 
 template<class T>
@@ -87,6 +88,7 @@ public:
 class ELFPluginProvider : public FilePluginProvider {
 protected:
 	virtual Plugin *createPlugin(const Common::FSNode &node) const = 0;
+	virtual PluginList getPlugins();
 
 	bool isPluginFilename(const Common::FSNode &node) const;
 };
diff --git a/backends/plugins/elf/memory-manager.cpp b/backends/plugins/elf/memory-manager.cpp
new file mode 100644
index 0000000000..6e573088e2
--- /dev/null
+++ b/backends/plugins/elf/memory-manager.cpp
@@ -0,0 +1,168 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "common/scummsys.h" 
+#include "common/util.h"
+#include "backends/plugins/elf/memory-manager.h"
+ 
+DECLARE_SINGLETON(ELFMemoryManager); 
+
+ELFMemoryManager::ELFMemoryManager() : 
+	_heap(0), _heapSize(0), _heapAlign(0), 
+	_trackAllocs(false), _measuredSize(0), _measuredAlign(0), 
+	_bytesAllocated(0) {}
+
+ELFMemoryManager::~ELFMemoryManager() {
+	free(_heap);
+	_heap = 0;
+}
+
+void ELFMemoryManager::trackPlugin(bool value) {
+	assert(!_heap);
+
+	if (value == _trackAllocs)
+		return;
+	
+	_trackAllocs = value;
+	
+	if (_trackAllocs) {	// start measuring
+		// start tracking allocations
+		_measuredAlign = 0;
+		
+	} else {	// we're done measuring
+		// get the total allocated size
+		size_t measuredSize = _allocList.back().end() - _allocList.front().start;
+
+		_heapSize = MAX(_heapSize, measuredSize);
+		_heapAlign = MAX(_heapAlign, _measuredAlign);
+		
+		_allocList.clear();
+		_bytesAllocated = 0;	// reset
+		
+		debug(2, "measured a plugin of size %d. Max size %d. Max align %d", measuredSize, _heapSize, _heapAlign);
+	}
+}
+
+void ELFMemoryManager::trackAlloc(size_t align, size_t size) {
+	if (!_measuredAlign)
+		_measuredAlign = align;
+		
+	// use the allocate function to simulate allocation
+	allocateOnHeap(align, size);
+}
+
+void ELFMemoryManager::allocateHeap() {
+	// The memory manager should only allocate once
+	assert (!_heap);
+	assert (_heapSize);
+	
+	// clear the list
+	_allocList.clear();
+	_bytesAllocated = 0;
+	
+	debug(2, "ELFMemoryManager: allocating %d bytes aligned at %d as the \
+			plugin heap", _heapSize, _heapAlign);
+	
+	// prepare the heap
+	if (_heapAlign) 
+		_heap = ::memalign(_heapAlign, _heapSize);
+	else
+		_heap = ::malloc(_heapSize);
+		
+	assert(_heap);
+}
+
+void *ELFMemoryManager::pluginAllocate(size_t size) {
+	if (_heap) {
+		return pluginAllocate(sizeof(void *), size);
+	}
+	return ::malloc(size);
+}
+
+void *ELFMemoryManager::pluginAllocate(size_t align, size_t size) {
+	if (_heap) {
+		return allocateOnHeap(align, size);
+	} 
+	return ::memalign(align, size);
+}
+
+void ELFMemoryManager::pluginDeallocate(void *ptr) {
+	if (_heap) {
+		return deallocateFromHeap(ptr);
+	}
+	return ::free(ptr);
+}
+
+// Allocate space for the request in our heap
+void *ELFMemoryManager::allocateOnHeap(size_t align, size_t size) {
+	byte *lastAddress = (byte *)_heap;
+	
+	// We can't allow allocations smaller than sizeof(Allocation). This could
+	// only be from non-plugin allocations and would cause infinite recursion 
+	// when allocating our Allocation in the list.
+	if (size <= sizeof(Allocation))
+		return 0;
+	
+	Common::List<Allocation>::iterator i;
+	for (i = _allocList.begin(); i != _allocList.end(); i++) {
+		if (i->start - lastAddress > (int)size) 
+			break;
+		lastAddress = i->end();
+		// align to desired alignment
+		if (align) {
+			lastAddress = (byte *)( ((size_t)lastAddress + align - 1) & ~(align - 1) );
+		}
+	}
+	
+	// Check if we exceeded our heap limit
+	// We skip this case if we're only tracking allocations
+	if (!_trackAllocs && ((size_t)lastAddress + size > (size_t)_heap + _heapSize)) {
+		debug(2, "failed to find space to allocate %d bytes", size);
+		return 0;
+	}
+	
+	_allocList.insert(i, Allocation(lastAddress, size));
+	_bytesAllocated += size;
+	
+	debug(7, "ELFMemoryManager: allocated %d bytes at %p. Total %d bytes", 
+		size, lastAddress, _bytesAllocated);
+	
+	return lastAddress;
+}
+
+void ELFMemoryManager::deallocateFromHeap(void *ptr) {
+	Common::List<Allocation>::iterator i;
+	for (i = _allocList.begin(); i != _allocList.end(); i++) {
+		if (i->start == ptr) {
+			_bytesAllocated -= (*i).size;
+			
+			debug(7, "ELFMemoryManager: freed %d bytes at %p. Total %d bytes", 
+				(*i).size, (*i).start, _bytesAllocated);
+			
+			_allocList.erase(i);
+			break;
+		}
+	}	
+}
diff --git a/backends/plugins/elf/memory-manager.h b/backends/plugins/elf/memory-manager.h
new file mode 100644
index 0000000000..5121ed163d
--- /dev/null
+++ b/backends/plugins/elf/memory-manager.h
@@ -0,0 +1,83 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#ifndef ELF_MEMORY_MANAGER_H
+#define ELF_MEMORY_MANAGER_H
+
+#include "common/singleton.h"
+#include "common/list.h"
+#include "common/mutex.h"
+ 
+/**
+ * A 'foolproof' way to prevent memory fragmentation. This class is used to 
+ * serve as a permanent allocation to prevent the process of loading and 
+ * unloading plugins from causing heavy fragmentation.
+ **/
+ 
+#define ELFMemMan		ELFMemoryManager::instance()
+ 
+class ELFMemoryManager : public Common::Singleton<ELFMemoryManager> {
+public:	
+	void trackPlugin(bool value);
+	void trackAlloc(size_t align, size_t size);
+
+	void allocateHeap();
+
+	void *pluginAllocate(size_t size);
+	void *pluginAllocate(uint32 align, uint32 size);
+	void pluginDeallocate(void *ptr);
+	
+private:
+   friend class Common::Singleton<ELFMemoryManager>;
+
+	ELFMemoryManager();
+	~ELFMemoryManager();
+
+	void *allocateOnHeap(size_t align, size_t size);
+	void deallocateFromHeap(void *ptr);
+	
+	struct Allocation {
+		byte *start;
+		size_t size;
+		byte *end() { return start + size; }
+		Allocation(byte *a, size_t b) : start(a), size(b) {}
+	};
+
+	// heap
+	void *_heap;
+	size_t _heapAlign;			// alignment of the heap
+	size_t _heapSize;			// size of the heap
+	
+	// tracking allocations
+	bool _trackAllocs;		// whether we are currently tracking
+	size_t _measuredSize; 
+	size_t _measuredAlign;	
+	
+	// real allocations
+	Common::List<Allocation> _allocList;
+	uint32 _bytesAllocated;
+};
+ 
+#endif /* ELF_MEMORY_MANAGER_H */
diff --git a/backends/plugins/elf/mips-loader.cpp b/backends/plugins/elf/mips-loader.cpp
index b25017af98..42af831ef4 100644
--- a/backends/plugins/elf/mips-loader.cpp
+++ b/backends/plugins/elf/mips-loader.cpp
@@ -28,6 +28,7 @@
 #if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) && defined(MIPS_TARGET)
 
 #include "backends/plugins/elf/mips-loader.h"
+#include "backends/plugins/elf/memory-manager.h"
 
 #include "common/debug.h"
 
@@ -281,7 +282,7 @@ bool MIPSDLObject::loadSegment(Elf32_Phdr *phdr) {
 	// We need to take account of non-allocated segment for shorts
 	if (phdr->p_flags & PF_X) {	// This is a relocated segment
 		// Attempt to allocate memory for segment
-		_segment = (byte *)memalign(phdr->p_align, phdr->p_memsz);
+		_segment = (byte *)ELFMemMan.pluginAllocate(phdr->p_align, phdr->p_memsz);
 
 		if (!_segment) {
 			warning("elfloader: Out of memory.");
@@ -289,7 +290,7 @@ bool MIPSDLObject::loadSegment(Elf32_Phdr *phdr) {
 		}
 
 		debug(2, "elfloader: Allocated segment @ %p", _segment);
-
+		
 		// Get offset to load segment into
 		baseAddress = _segment;
 		_segmentSize = phdr->p_memsz;