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#include "stdafx.h"
#include "Driver.h"
#include "Exception.h"
#include "Core/Convert.h"
#ifdef POSIX
#include <dlfcn.h>
#endif
#ifndef LOAD_LIBRARY_SEARCH_SYSTEM32
#define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
#endif
namespace sql {
// Note: These are globals, as loading of dynamic libraries is truly a global concern. It is not
// tied to different Engines.
// Lock to protect globals here.
util::Lock pgDriverLock;
// Global object that contains function pointers to the library.
PGDriver pgDriver;
// Instances that are active.
size_t pgInstances = 0;
static void throwNameError(Engine &e, const char *name) {
StrBuf *msg = new (e) StrBuf();
*msg << S("Could not find the function '") << toWChar(e, name)->v << S("' in the pqsql library.");
throw new (e) SQLError(msg->toS());
}
#if defined(WINDOWS)
// MSVC "hack" to get the address of the module:
extern "C" IMAGE_DOS_HEADER __ImageBase;
// Try to load a DLL relative to the specified module.
static HMODULE tryLoad(HMODULE relative, const wchar_t *name, StrBuf *error) {
std::vector<wchar_t> buffer(MAX_PATH + 1, 0);
do {
GetModuleFileName(relative, &buffer[0], DWORD(buffer.size()));
if (GetLastError() == ERROR_INSUFFICIENT_BUFFER) {
buffer.resize(buffer.size() * 2);
continue;
}
} while (false);
// Find the last backslash:
size_t pathEnd = buffer.size();
while (pathEnd > 0) {
if (buffer[pathEnd - 1] == '\\' || buffer[pathEnd - 1] == '/')
break;
pathEnd--;
}
// Try the path we are in.
buffer.resize(pathEnd + wcslen(name) + 1);
for (size_t j = 0; name[j]; j++)
buffer[pathEnd + j] = name[j];
buffer[buffer.size() - 1] = 0;
// Does the file exist at all?
if (GetFileAttributes(&buffer[0]) == INVALID_FILE_ATTRIBUTES)
return NULL;
// The LOAD_WITH_ALTERED_SEARCH_PATH is important to ensure that the dependent dlls are
// found by the loader.
HMODULE result = LoadLibraryEx(&buffer[0], NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
DWORD lastError = GetLastError();
if (lastError == ERROR_BAD_EXE_FORMAT) {
*error << S("\nThe file ") << &buffer[0] << S(" is for an incompatible platform.");
} else if (lastError == ERROR_MOD_NOT_FOUND) {
*error << S("\nOne of the dependent DLLs for the file ") << &buffer[0] << S(" was not found.");
}
return result;
}
void loadPgDriver(Engine &e) {
const wchar_t *name = L"libpq.dll";
HMODULE moduleHandle = (HMODULE)&__ImageBase;
#if 0
// Try to get the current DLL handle. Only needed if we are not compiling on MSVC.
if (!GetModuleHandleEx(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
| GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
(LPWSTR)&findDriverLib, // ptr to some function in the modle
&moduleHandle)) {
throw new (e) SQLError(new (e) Str(S("Could not find the path to the SQL lib DLL file.")));
}
#endif
StrBuf *errors = new (e) StrBuf();
*errors << S("Could not find and load the PostgreSQL driver (libpq.dll).");
// Relative to the SQL dll.
HMODULE lib = tryLoad(moduleHandle, name, errors);
if (!lib)
// Relative to the Storm.exe.
lib = tryLoad(NULL, name, errors);
if (!lib)
// In system paths.
lib = LoadLibraryEx(name, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
if (!lib)
throw new (e) SQLError(errors->toS());
#define PG_OPTIONAL_FUNCTION(name, result, ...) \
pgDriver.name = (PGDriver::Ptr ## name)GetProcAddress(lib, #name);
#define PG_FUNCTION(name, result, ...) \
PG_OPTIONAL_FUNCTION(name, result, __VA_ARGS__) \
if (!pgDriver.name) \
throwNameError(e, #name);
#include "DriverFns.inc"
#undef PG_FUNCTION
#undef PG_OPTIONAL_FUNCTION
}
#elif defined(POSIX)
void loadPgDriver(Engine &e) {
const char *names[] = {
"libpq.so.5",
"libpq.so",
null,
};
void *loaded = null;
for (const char **name = names; loaded == null && *name != null; name++) {
// Note: This respects rpath of the library if se wet it.
loaded = dlopen(*name, RTLD_NOW | RTLD_LOCAL);
}
if (!loaded) {
StrBuf *msg = new (e) StrBuf();
*msg << S("Failed to load the MariaDB library. Is it installed?\n");
*msg << S("Searched for the following names:");
for (const char **name = names; loaded == null && *name != null; name++) {
*msg << S("\n") << toWChar(e, *name)->v;
}
throw new (e) SQLError(msg->toS());
}
#define PG_OPTIONAL_FUNCTION(name, result, ...) \
pgDriver.name = (PGDriver::Ptr ## name)dlsym(loaded, #name);
#define PG_FUNCTION(name, result, ...) \
PG_OPTIONAL_FUNCTION(name, result, __VA_ARGS__) \
if (!pgDriver.name) \
throwNameError(e, #name);
#include "DriverFns.inc"
#undef PG_FUNCTION
#undef PG_OPTIONAL_FUNCTION
}
#endif
const PGDriver *createPGDriver(Engine &e) {
util::Lock::L z(pgDriverLock);
if (!pgDriver.PQconnectdb) {
loadPgDriver(e);
}
pgInstances++;
return &pgDriver;
}
void destroyPGDriver(const PGDriver *driver) {
util::Lock::L z(pgDriverLock);
pgInstances--;
// TODO: Unload after a delay?
}
}
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