[vlc-devel] [PATCH 1/2] [RFC] core: add a function to load a system shared library
Steve Lhomme
robux4 at gmail.com
Thu Mar 9 16:55:34 CET 2017
On Thu, Mar 9, 2017 at 4:14 PM, Rémi Denis-Courmont <remi at remlab.net> wrote:
> On March 9, 2017 12:50:14 PM GMT+02:00, Steve Lhomme <robux4 at videolabs.io> wrote:
>>it cannot be loaded from anywhere but the system
>>---
>> include/vlc_modules.h | 13 ++++++++++++
>> src/libvlccore.sym | 1 +
>> src/missing.c | 7 +++++++
>> src/network/udp.c | 3 ++-
>> src/text/url.c | 2 +-
>>src/win32/plugin.c | 57
>>+++++++++++++++++++++++++++++++++++++++++++++++++++
>> 6 files changed, 81 insertions(+), 2 deletions(-)
>>
>>diff --git a/include/vlc_modules.h b/include/vlc_modules.h
>>index 7f45217969..ec5c69c36a 100644
>>--- a/include/vlc_modules.h
>>+++ b/include/vlc_modules.h
>>@@ -65,6 +65,19 @@ VLC_API const char * module_get_capability( const
>>module_t *m ) VLC_USED;
>> VLC_API int module_get_score( const module_t *m ) VLC_USED;
>>VLC_API const char * module_gettext( const module_t *, const char * )
>>VLC_USED;
>>
>>+#ifdef _WIN32
>>+typedef HMODULE vlc_lib_handle_t;
>>+#else
>>+typedef void *vlc_lib_handle_t;
>>+#endif
>>+
>>+/**
>>+ * Load a system library (DLL) in memory.
>>+ *
>>+ * @param libname the name of system library to load.
>>+ */
>>+VLC_API vlc_lib_handle_t vlc_load_syslib(const char *libname);
>>+
>> VLC_USED static inline module_t *module_get_main (void)
>> {
>> return module_find ("core");
>>diff --git a/src/libvlccore.sym b/src/libvlccore.sym
>>index 57c83495a3..1c0e6ee0a3 100644
>>--- a/src/libvlccore.sym
>>+++ b/src/libvlccore.sym
>>@@ -462,6 +462,7 @@ us_vasprintf
>> vlc_close
>> vlc_fopen
>> utf8_fprintf
>>+vlc_load_syslib
>> vlc_loaddir
>> vlc_lstat
>> vlc_mkdir
>>diff --git a/src/missing.c b/src/missing.c
>>index c76e99a4bc..99670c8e95 100644
>>--- a/src/missing.c
>>+++ b/src/missing.c
>>@@ -442,3 +442,10 @@ update_release_t *update_GetRelease(update_t *u)
>> vlc_assert_unreachable();
>> }
>> #endif /* !UPDATE_CHECK */
>>+
>>+#ifndef _WIN32
>>+void *vlc_load_syslib(const char *libname)
>>+{
>>+ return NULL;
>>+}
>>+#endif
>>diff --git a/src/network/udp.c b/src/network/udp.c
>>index d098fb1425..bf3dc2266a 100644
>>--- a/src/network/udp.c
>>+++ b/src/network/udp.c
>>@@ -36,6 +36,7 @@
>> #include <errno.h>
>> #include <assert.h>
>>
>>+#include <vlc_modules.h>
>> #include <vlc_network.h>
>>
>> #ifdef _WIN32
>>@@ -105,7 +106,7 @@ static int net_SetupDgramSocket (vlc_object_t
>>*p_obj, int fd,
>> * receive buffer if that isn't present
>> */
>> #if (_WIN32_WINNT < _WIN32_WINNT_WIN8)
>>- HINSTANCE h_Network = LoadLibrary(TEXT("Windows.Networking.dll"));
>>+ HMODULE h_Network = vlc_load_syslib("Windows.Networking.dll");
>> if( (h_Network == NULL) ||
>>(GetProcAddress( h_Network, "SetSocketMediaStreamingMode" ) == NULL ) )
>> {
>>diff --git a/src/text/url.c b/src/text/url.c
>>index 1b602b599e..682ea9665d 100644
>>--- a/src/text/url.c
>>+++ b/src/text/url.c
>>@@ -837,7 +837,7 @@ char *vlc_uri_fixup(const char *str)
>> # define IDN_ALLOW_UNASSIGNED 0x01
>>static int IdnToAscii(DWORD flags, LPCWSTR str, int len, LPWSTR buf,
>>int size)
>> {
>>- HMODULE h = LoadLibrary(_T("Normaliz.dll"));
>>+ HMODULE h = vlc_load_syslib("Normaliz.dll");
>> if (h == NULL)
>> {
>> errno = ENOSYS;
>>diff --git a/src/win32/plugin.c b/src/win32/plugin.c
>>index 1a65521fca..6bade68fbc 100644
>>--- a/src/win32/plugin.c
>>+++ b/src/win32/plugin.c
>>@@ -29,6 +29,7 @@
>>
>> #include <vlc_common.h>
>> #include <vlc_charset.h>
>>+#include <vlc_modules.h>
>> #include "modules/modules.h"
>> #include <windows.h>
>> #include <wchar.h>
>>@@ -133,3 +134,59 @@ void *module_Lookup( module_handle_t handle, const
>>char *psz_function )
>> {
>> return (void *)GetProcAddress( handle, (char *)psz_function );
>> }
>>+
>>+HMODULE vlc_load_syslib(const char *libname)
>>+{
>>+ HMODULE module;
>>+ bool has_KB2533623 = true;
>>+ TCHAR *tlibname;
>>+#if (_WIN32_WINNT < _WIN32_WINNT_WIN8)
>>+ /* check for KB2533623 */
>>+ if (GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")),
>>+ "SetDefaultDllDirectories") ==
>>NULL)
>>+ has_KB2533623 = false;
>>+#endif
>>+
>>+#ifdef UNICODE
>>+ tlibname = ToWide(libname);
>>+ if (unlikely(tlibname==NULL))
>>+ return NULL;
>>+#else
>>+ tlibname = libname;
>>+#endif
>>+
>>+ if (false && has_KB2533623)
>>+ module = LoadLibraryEx(tlibname, NULL,
>>LOAD_LIBRARY_SEARCH_SYSTEM32);
>>+ else
>>+ {
>>+ /* force the path of the DLL inside system32 */
>>+ DWORD systemLen = GetSystemDirectory(NULL, 0);
>>+ if (systemLen) {
>>+ systemLen += 1 + _tcslen(tlibname);
>>+ TCHAR *sysdir = malloc(systemLen * sizeof(*sysdir));
>>+ if (likely(sysdir!=NULL)) {
>>+ if (GetSystemDirectory(sysdir, systemLen)) {
>>+ _tcsncat(sysdir, _T("\\"), systemLen);
>>+ _tcsncat(sysdir, tlibname, systemLen);
>>+
>>+#ifdef UNICODE
>>+ free(tlibname);
>>+#endif
>>+ tlibname = sysdir;
>>+ }
>>+ }
>>+ }
>>+
>>+ module = LoadLibrary(tlibname);
>>+
>>+ if ((const char*)tlibname != libname) {
>>+ free(tlibname);
>>+ tlibname = NULL; /* no double free on unicode */
>>+ }
>>+ }
>>+
>>+#ifdef UNICODE
>>+ free(tlibname);
>>+#endif
>>+ return module;
>>+}
>>--
>>2.11.1
>>
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>
> This looks rather out of place as it is too platform specific.
It would be used multiple times in the core and in many modules. Also
it might be useful on other OSes too. For example it may be possible
to hack an OS X .app bundle by adding fake system shared libraries in
it.
> --
> Rémi Denis-Courmont
> _______________________________________________
> vlc-devel mailing list
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