[patch] load wininet dynamically in cygcheck
Brian Dessent
brian@dessent.net
Fri Jan 13 18:49:00 GMT 2006
This uses LoadLibrary and GetProcAddress instead of -lwininet so that systems
lacking IE3 can still run cygcheck. Tested on XP and NT4, and verified that
with WININET.DLL renamed cygcheck can still function.
2006-01-13 Brian Dessent <brian@dessent.net>
* Makefile.in (cygcheck.exe): Do not link against libwininet.a.
* cygcheck.cc (pInternetCloseHandle): Define global function pointer.
(display_internet_error): Use it.
(package_grep): Attempt to load wininet.dll at runtime. Call WinInet
API through function pointers throughout.
Brian
-------------- next part --------------
Index: Makefile.in
===================================================================
RCS file: /cvs/src/src/winsup/utils/Makefile.in,v
retrieving revision 1.58
diff -u -p -r1.58 Makefile.in
--- Makefile.in 22 Nov 2005 17:19:17 -0000 1.58
+++ Makefile.in 13 Jan 2006 18:39:16 -0000
@@ -99,15 +99,15 @@ else
$(CXX) $(MINGW_CXXFLAGS) -o $@ ${wordlist 1,2,$^} -B$(mingw_build)/ $(MINGW_LDFLAGS)
endif
-cygcheck.exe: cygcheck.o path.o dump_setup.o $(MINGW_DEP_LDLIBS) $(w32api_lib)/libwininet.a
+cygcheck.exe: cygcheck.o path.o dump_setup.o $(MINGW_DEP_LDLIBS)
ifeq "$(libz)" ""
@echo '*** Building cygcheck without package content checking due to missing mingw libz.a.'
endif
ifdef VERBOSE
- $(CXX) $(MINGW_CXXFLAGS) -o $@ ${wordlist 1,3,$^} -B$(mingw_build)/ $(MINGW_LDFLAGS) $(libz) $(w32api_lib)/libwininet.a
+ $(CXX) $(MINGW_CXXFLAGS) -o $@ ${wordlist 1,3,$^} -B$(mingw_build)/ $(MINGW_LDFLAGS) $(libz)
else
- @echo $(CXX) -o $@ ${wordlist 1,3,$^} ${filter-out -B%, $(MINGW_CXXFLAGS) $(MINGW_LDFLAGS)} $(libz) $(w32api_lib)/libwininet.a;\
- $(CXX) $(MINGW_CXXFLAGS) -o $@ ${wordlist 1,3,$^} -B$(mingw_build)/ $(MINGW_LDFLAGS) $(libz) $(w32api_lib)/libwininet.a
+ @echo $(CXX) -o $@ ${wordlist 1,3,$^} ${filter-out -B%, $(MINGW_CXXFLAGS) $(MINGW_LDFLAGS)} $(libz);\
+ $(CXX) $(MINGW_CXXFLAGS) -o $@ ${wordlist 1,3,$^} -B$(mingw_build)/ $(MINGW_LDFLAGS) $(libz)
endif
dumper.o: dumper.cc dumper.h
Index: cygcheck.cc
===================================================================
RCS file: /cvs/src/src/winsup/utils/cygcheck.cc,v
retrieving revision 1.83
diff -u -p -r1.83 cygcheck.cc
--- cygcheck.cc 13 Jan 2006 13:39:05 -0000 1.83
+++ cygcheck.cc 13 Jan 2006 18:39:16 -0000
@@ -37,6 +37,10 @@ int find_package = 0;
int list_package = 0;
int grep_packages = 0;
+/* This is global because it's used in both internet_display_error as well
+ as package_grep. */
+BOOL (WINAPI *pInternetCloseHandle) (HINTERNET);
+
#ifdef __GNUC__
typedef long long longlong;
#else
@@ -161,7 +165,7 @@ display_internet_error (const char *mess
va_start (hptr, message);
while ((h = va_arg (hptr, HINTERNET)) != 0)
- InternetCloseHandle (h);
+ pInternetCloseHandle (h);
va_end (hptr);
return 1;
@@ -1588,6 +1592,43 @@ package_grep (char *search)
{
char buf[1024];
+ /* Attempt to dynamically load the necessary WinInet API functions so that
+ cygcheck can still function on older systems without IE. */
+ HMODULE hWinInet;
+ if (!(hWinInet = LoadLibrary ("wininet.dll")))
+ {
+ fputs ("Unable to locate WININET.DLL. This feature requires Microsoft "
+ "Internet Explorer v3 or later to function.\n", stderr);
+ return 1;
+ }
+
+ /* InternetCloseHandle is used outside this function so it is declared
+ global. The rest of these functions are only used here, so declare them
+ and call GetProcAddress for each of them with the following macro. */
+
+ pInternetCloseHandle = (BOOL (WINAPI *) (HINTERNET))
+ GetProcAddress (hWinInet, "InternetCloseHandle");
+#define make_func_pointer(name, ret, args) ret (WINAPI * p##name) args = \
+ (ret (WINAPI *) args) GetProcAddress (hWinInet, #name);
+ make_func_pointer (InternetAttemptConnect, DWORD, (DWORD));
+ make_func_pointer (InternetOpenA, HINTERNET, (LPCSTR, DWORD, LPCSTR, LPCSTR,
+ DWORD));
+ make_func_pointer (InternetOpenUrlA, HINTERNET, (HINTERNET, LPCSTR, LPCSTR,
+ DWORD, DWORD, DWORD));
+ make_func_pointer (InternetReadFile, BOOL, (HINTERNET, PVOID, DWORD, PDWORD));
+ make_func_pointer (HttpQueryInfoA, BOOL, (HINTERNET, DWORD, PVOID, PDWORD,
+ PDWORD));
+#undef make_func_pointer
+
+ if(!pInternetCloseHandle || !pInternetAttemptConnect || !pInternetOpenA
+ || !pInternetOpenUrlA || !pInternetReadFile || !pHttpQueryInfoA)
+ {
+ fputs ("Unable to load one or more functions from WININET.DLL. This "
+ "feature requires Microsoft Internet Explorer v3 or later to "
+ "function.\n", stderr);
+ return 1;
+ }
+
/* construct the actual URL by escaping */
char *url = (char *) alloca (sizeof (base_url) + strlen (search) * 3);
strcpy (url, base_url);
@@ -1610,7 +1651,7 @@ package_grep (char *search)
*dest = 0;
/* Connect to the net and open the URL. */
- if (InternetAttemptConnect (0) != ERROR_SUCCESS)
+ if (pInternetAttemptConnect (0) != ERROR_SUCCESS)
{
fputs ("An internet connection is required for this function.\n", stderr);
return 1;
@@ -1618,16 +1659,16 @@ package_grep (char *search)
/* Initialize WinInet and attempt to fetch our URL. */
HINTERNET hi = NULL, hurl = NULL;
- if (!(hi = InternetOpen ("cygcheck", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0)))
+ if (!(hi = pInternetOpenA ("cygcheck", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0)))
return display_internet_error ("InternetOpen() failed", NULL);
- if (!(hurl = InternetOpenUrl (hi, url, NULL, 0, 0, 0)))
+ if (!(hurl = pInternetOpenUrlA (hi, url, NULL, 0, 0, 0)))
return display_internet_error ("unable to contact cygwin.com site, "
"InternetOpenUrl() failed", hi, NULL);
/* Check the HTTP response code. */
DWORD rc = 0, rc_s = sizeof (DWORD);
- if (!HttpQueryInfo (hurl, HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER,
+ if (!pHttpQueryInfoA (hurl, HTTP_QUERY_STATUS_CODE | HTTP_QUERY_FLAG_NUMBER,
(void *) &rc, &rc_s, NULL))
return display_internet_error ("HttpQueryInfo() failed", hurl, hi, NULL);
@@ -1642,15 +1683,15 @@ package_grep (char *search)
DWORD numread;
do
{
- if (!InternetReadFile (hurl, (void *) buf, sizeof (buf), &numread))
+ if (!pInternetReadFile (hurl, (void *) buf, sizeof (buf), &numread))
return display_internet_error ("InternetReadFile failed", hurl, hi, NULL);
if (numread)
fwrite ((void *) buf, (size_t) numread, 1, stdout);
}
while (numread);
- InternetCloseHandle (hurl);
- InternetCloseHandle (hi);
+ pInternetCloseHandle (hurl);
+ pInternetCloseHandle (hi);
return 0;
}
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