These macros are soooooooo ugly!
why not do this simply like other examples in OpenVPN code, if I
recall correctly in CryptoAPI module.
On Wed, Aug 17, 2011 at 4:42 PM, Heiko Hund <heiko.h...@sophos.com> wrote:
> MinGW is missing support for winhttp.dll which will be used for automatic
> proxy server detection in Windows. Until it becomes available the workaround
> performed is to provide wrapper functions and dynamically map the missing
> library into the address space, get the function pointer for the actual API
> and call it with the arguments provided.
>
> To keep things managable and short in the source code two preprocessor macros
> are defined that do most of the work.
>
> Signed-off-by: Heiko Hund <heiko.h...@sophos.com>
> ---
> configure.ac | 30 ++++++++++++++++
> win32.c | 108
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> win32.h | 61 ++++++++++++++++++++++++++++++++
> 3 files changed, 199 insertions(+), 0 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index a3789d9..42d46cb 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -665,6 +665,36 @@ if test "${WIN32}" = "yes"; then
> fi
>
> dnl
> +dnl Check if MinGW knows about WinHTTP API
> +dnl
> +if test "${WIN32}" = "yes"; then
> + AC_MSG_CHECKING([if MinGW knows about WinHTTP])
> + AC_TRY_LINK([
> + #include <windows.h>
> + #include <winhttp.h>
> + ], [
> + LPWSTR *url;
> + HINTERNET session;
> + WINHTTP_PROXY_INFO proxy_info;
> + WINHTTP_AUTOPROXY_OPTIONS proxy_options;
> + WINHTTP_CURRENT_USER_IE_PROXY_CONFIG ie_proxy_info;
> +
> + WinHttpGetDefaultProxyConfiguration (&proxy_info);
> + WinHttpGetIEProxyConfigForCurrentUser (&ie_proxy_info);
> + WinHttpDetectAutoProxyConfigUrl (WINHTTP_AUTO_DETECT_TYPE_DHCP |
> WINHTTP_AUTO_DETECT_TYPE_DNS_A, url);
> + session = WinHttpOpen (NULL, WINHTTP_ACCESS_TYPE_NO_PROXY,
> WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
> + WinHttpGetProxyForUrl (session, L"http://openvpn.net";,
> &proxy_options, &proxy_info);
> + WinHttpCloseHandle (session);
> + ], [
> + AC_MSG_RESULT([yes])
> + ], [
> + AC_MSG_RESULT([no.])
> + AC_MSG_NOTICE([Enabling WinHTTP compatibility layer.])
> + AC_DEFINE(USE_WINHTTP_COMPAT, 1, [Use the WinHTTP compatibility
> layer])
> + ])
> +fi
> +
> +dnl
> dnl check for LZO library
> dnl
>
> diff --git a/win32.c b/win32.c
> index cf6cc2d..15743a8 100644
> --- a/win32.c
> +++ b/win32.c
> @@ -1128,4 +1128,112 @@ win_get_tempdir()
> }
> return tmpdir;
> }
> +
> +
> +#ifdef USE_WINHTTP_COMPAT
> +
> +/*
> + * MinGW is missing support for winhttp.dll which is used for automatic
> + * proxy server detection. Until it becomes available the workaround is
> + * to dynamically map the library into the address space and get the
> + * function pointers for the APIs that are used. The two macros below
> + * do just that.
> + *
> + * PROVIDE_WIN32_LIBRARY provides means to access API functions.
> + * Arguments: LIB - name of the DLL to load
> + *
> + * DEFINE_WIN32_WRAPPER defines a wrapper function around the
> + * original API provoded by the library. The original API can
> + * be accessed within the wrapper as <LIB>_<FUNC> (see Arguments).
> + * Arguments: LIB name of the DLL the function is exported in
> + * ERR value to return in case something goes wrong
> + * RET API function's return value type
> + * FUNC exported name of the API function
> + * ARGS declaration of the API function arguments
> + * BODY the wrapper function's body
> + */
> +
> +#define PROVIDE_WIN32_LIBRARY(LIB) \
> + static HMODULE get_ ## LIB ## _library () \
> + { \
> + static HMODULE lib = NULL; \
> + \
> + if (lib == NULL) \
> + { \
> + char name[MAX_PATH]; \
> + UINT len = GetSystemDirectory (name, sizeof (name)); \
> + if (len == 0) \
> + return NULL; \
> + \
> + strncpy (name + len, "\\" #LIB ".dll", sizeof (name) - len); \
> + name[sizeof (name) - 1] = '\0'; \
> + \
> + lib = LoadLibrary (name); \
> + } \
> + \
> + return lib; \
> + }
> +
> +#define DEFINE_WIN32_WRAPPER(LIB, ERR, RET, FUNC, ARGS, BODY) \
> + RET FUNC ARGS \
> + { \
> + typedef RET (WINAPI *(FUNC ## _fn)) ARGS; \
> + static FUNC ## _fn LIB ## _ ## FUNC = NULL; \
> + \
> + if ((LIB ## _ ## FUNC) == NULL) \
> + { \
> + union { \
> + FUNC ## _fn *type; \
> + FARPROC *ptr; \
> + } u = { .type = &(LIB ## _ ## FUNC) }; \
> + \
> + HMODULE lib = get_ ## LIB ## _library (); \
> + if (lib == NULL) \
> + return (ERR); \
> + \
> + *(u.ptr) = GetProcAddress (lib, (#FUNC)); \
> + if ((LIB ## _ ## FUNC) == NULL) \
> + return (ERR); \
> + } \
> + \
> + BODY \
> + }
> +
> +
> +PROVIDE_WIN32_LIBRARY (winhttp)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, NULL, HINTERNET,
> +WinHttpOpen, (LPCWSTR user_agent, DWORD access_type, LPCWSTR proxy, LPCWSTR
> bypass, DWORD flags),
> + return winhttp_WinHttpOpen (user_agent, access_type, proxy, bypass, flags);
> +)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, FALSE, BOOL,
> +WinHttpCloseHandle, (HINTERNET session),
> + return winhttp_WinHttpCloseHandle (session);
> +)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, FALSE, BOOL,
> +WinHttpGetDefaultProxyConfiguration, (WINHTTP_PROXY_INFO *proxy_info),
> + return winhttp_WinHttpGetDefaultProxyConfiguration (proxy_info);
> +)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, FALSE, BOOL,
> +WinHttpGetIEProxyConfigForCurrentUser, (WINHTTP_CURRENT_USER_IE_PROXY_CONFIG
> *proxy_config),
> + return winhttp_WinHttpGetIEProxyConfigForCurrentUser(proxy_config);
> +)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, FALSE, BOOL,
> +WinHttpDetectAutoProxyConfigUrl, (DWORD flags, LPWSTR *url),
> + return winhttp_WinHttpDetectAutoProxyConfigUrl (flags, url);
> +)
> +
> +DEFINE_WIN32_WRAPPER (winhttp, FALSE, BOOL,
> +WinHttpGetProxyForUrl, (HINTERNET session, LPCWSTR url,
> + WINHTTP_AUTOPROXY_OPTIONS *options,
> + WINHTTP_PROXY_INFO *proxy_info),
> + return winhttp_WinHttpGetProxyForUrl (session, url, options, proxy_info);
> +)
> +
> +#endif /* USE_WINHTTP_COMPAT */
> +
> #endif
> diff --git a/win32.h b/win32.h
> index 87d8ecc..2ff4b8c 100644
> --- a/win32.h
> +++ b/win32.h
> @@ -288,5 +288,66 @@ int inet_pton(int af, const char *src, void *st);
> /* Find temporary directory */
> const char *win_get_tempdir();
>
> +/*
> + * If MinGW does not know about the WinHTTP C API functions and
> + * constants that are used for automatic proxy server detection
> + * they are declared here. For detailed information see:
> + * http://msdn.microsoft.com/en-us/library/aa384252%28v=VS.85%29.aspx
> + */
> +#ifdef USE_WINHTTP_COMPAT
> +
> +#include <windows.h>
> +#include <wininet.h>
> +
> +/* WINHTTP_PROXY_INFO dwAccessType constants */
> +/* and WinHttpOpen() access_type */
> +#define WINHTTP_ACCESS_TYPE_NO_PROXY 1
> +#define WINHTTP_ACCESS_TYPE_NAMED_PROXY 3
> +
> +/* WinHttpDetectAutoProxyConfigUrl() flags */
> +#define WINHTTP_AUTO_DETECT_TYPE_DHCP 1
> +#define WINHTTP_AUTO_DETECT_TYPE_DNS_A 2
> +
> +/* WINHTTP_AUTOPROXY_OPTIONS dwFlags */
> +#define WINHTTP_AUTOPROXY_CONFIG_URL 2
> +
> +/* WinHttpOpen() proxy and bypass values */
> +#define WINHTTP_NO_PROXY_NAME 0
> +#define WINHTTP_NO_PROXY_BYPASS 0
> +
> +typedef struct {
> + DWORD dwAccessType;
> + LPWSTR lpszProxy;
> + LPWSTR lpszProxyBypass;
> +} WINHTTP_PROXY_INFO;
> +
> +typedef struct {
> + BOOL fAutoDetect;
> + LPWSTR lpszAutoConfigUrl;
> + LPWSTR lpszProxy;
> + LPWSTR lpszProxyBypass;
> +} WINHTTP_CURRENT_USER_IE_PROXY_CONFIG;
> +
> +typedef struct {
> + DWORD dwFlags;
> + DWORD dwAutoDetectFlags;
> + LPCWSTR lpszAutoConfigUrl;
> + LPVOID lpvReserved;
> + DWORD dwReserved;
> + BOOL fAutoLogonIfChallenged;
> +} WINHTTP_AUTOPROXY_OPTIONS;
> +
> +HINTERNET WinHttpOpen (LPCWSTR user_agent, DWORD access_type,
> + LPCWSTR proxy, LPCWSTR bypass, DWORD flags);
> +BOOL WinHttpCloseHandle (HINTERNET session);
> +BOOL WinHttpGetDefaultProxyConfiguration (WINHTTP_PROXY_INFO *proxy_info);
> +BOOL WinHttpGetIEProxyConfigForCurrentUser
> (WINHTTP_CURRENT_USER_IE_PROXY_CONFIG *proxy_config);
> +BOOL WinHttpDetectAutoProxyConfigUrl (DWORD flags, LPWSTR *url);
> +BOOL WinHttpGetProxyForUrl (HINTERNET session, LPCWSTR url,
> + WINHTTP_AUTOPROXY_OPTIONS *options,
> + WINHTTP_PROXY_INFO *proxy_info);
> +
> +#endif /* USE_WINHTTP_COMPAT */
> +
> #endif
> #endif
> --
> 1.7.5.4
>
>
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