Wrap Single .so file

[alcubierre-drive]

I was wondering whether it would be possible to use the functionality of this project to wrap a single library to provide an aarch64 version of a x86_64 .so file.

[ptitSeb]

It maybe be possible yes. It would depend on the lib. C lib might work. C++ or other language probably not.

[alcubierre-drive]

I'm particularly interested in wrapping libwidevinecdm.so as this library doesn't exist on aarch64... It should be C, not C++

[ptitSeb]

a nm -D libwidevinecdm.so would give some insight on how many symbols are present.
The other difficulty would be to find the signature of the functions (maybe in chrome sources?).

[alcubierre-drive]

             U abort
             U bcmp
             U catclose
             U catgets
             U catopen
             U clock_gettime

0000000000446890 T CreateCdmInstance
U __ctype_get_mb_cur_max
U __cxa_atexit
w __cxa_finalize
0000000000446850 T DeinitializeCdmModule
U dlclose
U dlsym
U __errno_location
U exp
U fclose
U fcntl
U fflush
U fgets
U fopen64
U fprintf
U fputc
U freelocale
U fwrite
U getauxval
U getc
0000000000446a20 T GetCdmVersion
U getenv
U getpid
U gettimeofday
w gmon_start
0000000000446820 T InitializeCdmModule_4
U __isnan
U __isoc99_sscanf
U __isoc99_vsscanf
w _ITM_deregisterTMCloneTable
w _ITM_registerTMCloneTable
U __libc_calloc
U __libc_free
U __libc_malloc
U __libc_memalign
U __libc_realloc
U localtime_r
U longjmp
U madvise
U mbrtowc
U mbsnrtowcs
U mbsrtowcs
U mbtowc
U memcmp
U memcpy
U __memcpy_chk
U memmove
U memset
U mmap64
U munmap
U nanosleep
U newlocale
U open64
w OPENSSL_memory_alloc
w OPENSSL_memory_free
w OPENSSL_memory_get_size
U perror
U prctl
U pthread_attr_destroy
U pthread_attr_init
U pthread_attr_setstacksize
U pthread_cond_broadcast
U pthread_cond_destroy
U pthread_cond_init
U pthread_cond_signal
U pthread_cond_wait
U pthread_create
U pthread_getspecific
U pthread_join
U pthread_key_create
U pthread_mutexattr_destroy
U pthread_mutexattr_init
U pthread_mutex_destroy
U pthread_mutex_init
U pthread_mutex_lock
U pthread_mutex_trylock
U pthread_mutex_unlock
U pthread_once
U pthread_rwlock_destroy
U pthread_rwlock_init
U pthread_rwlock_rdlock
U pthread_rwlock_unlock
U pthread_rwlock_wrlock
U pthread_self
U pthread_setspecific
U qsort
U rand
U read
U __register_atfork
U __sched_cpucount
U sched_getaffinity
w sdallocx
U sem_destroy
U sem_init
U sem_post
U sem_trywait
U sem_wait
U _setjmp
U snprintf
U __stack_chk_fail
U stderr
U stdin
U stdout
U strchr
U strcmp
U strerror_r
U strftime_l
U strlen
U strtod_l
U strtof_l
U strtol
U strtold_l
U strtoll_l
U strtoul
U strtoull_l
U syscall
U sysconf
U __tls_get_addr
U ungetc
U _Unwind_DeleteException
U _Unwind_GetIP
U _Unwind_GetLanguageSpecificData
U _Unwind_GetRegionStart
U _Unwind_RaiseException
U _Unwind_Resume
U _Unwind_SetGR
U _Unwind_SetIP
U uselocale
U usleep
U vasprintf
0000000000446a30 T VerifyCdmHost_0
U vfprintf
U vsnprintf
U __vsnprintf_chk
U wcrtomb
U wcslen
U wcsnrtombs
U wmemcpy
U wmemmove
U wmemset

[alcubierre-drive]

The nm -D output is easy to get, for the signatures I'd have to dig through the chromium sources more thoroughly...

[alcubierre-drive]

I could actually find it!

[ptitSeb]

Seems to quite heavy on the c++ side. I need to study that later, but it seems heavy / difficult yes.

[alcubierre-drive]

CDM_API void INITIALIZE_CDM_MODULE();

CDM_API void DeinitializeCdmModule();

// Returns a pointer to the requested CDM Host interface upon success.
// Returns NULL if the requested CDM Host interface is not supported.
// The caller should cast the returned pointer to the type matching
// |host_interface_version|.
typedef void* (*GetCdmHostFunc)(int host_interface_version, void* user_data);

// Returns a pointer to the requested CDM upon success.
// Returns NULL if an error occurs or the requested |cdm_interface_version| or
// |key_system| is not supported or another error occurs.
// The caller should cast the returned pointer to the type matching
// |cdm_interface_version|.
// Caller retains ownership of arguments and must call Destroy() on the returned
// object.
CDM_API void* CreateCdmInstance(int cdm_interface_version,
                                const char* key_system,
                                uint32_t key_system_size,
                                GetCdmHostFunc get_cdm_host_func,
                                void* user_data);

CDM_API const char* GetCdmVersion();

[alcubierre-drive]

These should be the corresponding c functions/types

[ptitSeb]

Ses, but the issue is with this callback: GetCdmHostFunc that will basicaly just return a void* that need to be casted to the relevant signature function, like a glXGetProcAddress(...), and this is were things gets messy.