149 lines
3.3 KiB
C++
149 lines
3.3 KiB
C++
//========= Copyright Valve Corporation, All rights reserved. ============//
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//
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// Purpose: Shared library loading and symbol lookup.
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//
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// $NoKeywords: $
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//=============================================================================//
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#include "pch_tier0.h"
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#include "tier0/dynfunction.h"
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#if defined(WIN32)
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typedef HMODULE LibraryHandle;
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#define LoadLibraryHandle(libname) LoadLibrary(libname)
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#define CloseLibraryHandle(handle) FreeLibrary(handle)
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#define LookupInLibraryHandle(handle, fn) GetProcAddress(handle, fn)
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#elif defined(POSIX)
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#include <dlfcn.h>
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typedef void *LibraryHandle;
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#define LoadLibraryHandle(libname) dlopen(libname, RTLD_NOW)
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#define CloseLibraryHandle(handle) dlclose(handle)
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#define LookupInLibraryHandle(handle, fn) dlsym(handle, fn)
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#else
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#error Please define your platform.
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#endif
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#if 1
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static inline void dbgdynfn(const char *fmt, ...) {}
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#else
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#define dbgdynfn printf
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#endif
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// NOTE: This has to be the last file included!
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#include "tier0/memdbgon.h"
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class CSharedLibraryCache
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{
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public:
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static CSharedLibraryCache &GetCache()
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{
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static CSharedLibraryCache Singleton;
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return Singleton;
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}
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struct CSharedLibraryItem
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{
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CSharedLibraryItem(LibraryHandle handle, const char *name)
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{
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m_handle = handle;
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m_name = new char[strlen(name) + 1];
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m_next = NULL;
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strcpy(m_name, name);
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}
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~CSharedLibraryItem()
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{
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dbgdynfn("CDynamicFunction: Closing library '%s' (%p)\n", m_name, (void *) m_handle);
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CloseLibraryHandle(m_handle);
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delete[] m_name;
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delete m_next;
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}
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char *m_name;
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CSharedLibraryItem *m_next;
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LibraryHandle m_handle;
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};
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CSharedLibraryCache() : m_pList(NULL) {}
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~CSharedLibraryCache() { CloseAllLibraries(); }
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LibraryHandle GetHandle(const char *name)
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{
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CSharedLibraryItem *item = GetCacheItem(name);
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if (item == NULL)
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{
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LibraryHandle lib = LoadLibraryHandle(name);
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dbgdynfn("CDynamicFunction: Loading library '%s' (%p)\n", name, (void *) lib);
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if (lib == NULL)
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return NULL;
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item = new CSharedLibraryItem(lib, name);
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item->m_next = m_pList;
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m_pList = item;
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}
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return item->m_handle;
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}
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void CloseLibrary(const char *name)
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{
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CSharedLibraryItem *item = GetCacheItem(name);
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if (item)
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{
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assert(item == m_pList);
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m_pList = item->m_next;
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item->m_next = NULL;
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delete item;
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}
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}
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void CloseAllLibraries()
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{
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delete m_pList;
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}
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private:
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CSharedLibraryItem *GetCacheItem(const char *name)
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{
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CSharedLibraryItem *prev = NULL;
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CSharedLibraryItem *item = m_pList;
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while (item)
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{
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if (strcmp(item->m_name, name) == 0)
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{
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// move this item to the front of the list, since there will
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// probably be a big pile of these lookups in a row
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// and then none ever again.
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if (prev != NULL)
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{
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prev->m_next = item->m_next;
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item->m_next = m_pList;
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m_pList = item;
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}
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return item;
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}
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prev = item;
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item = item->m_next;
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}
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return NULL; // not found.
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}
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CSharedLibraryItem *m_pList;
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};
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void *VoidFnPtrLookup_Tier0(const char *libname, const char *fn, void *fallback)
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{
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LibraryHandle lib = CSharedLibraryCache::GetCache().GetHandle(libname);
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void *retval = NULL;
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if (lib != NULL)
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{
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retval = LookupInLibraryHandle(lib, fn);
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dbgdynfn("CDynamicFunction: Lookup of '%s' in '%s': %p\n", fn, libname, retval);
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}
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if (retval == NULL)
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retval = fallback;
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return retval;
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}
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