I did a little bit more research. The combination that actually fails is RTLD_LAZY | RTLD_GLOBAL (what guile uses). So, you can actually use:
- RTLD_LAZY | RTLD_GLOBAL - RTLD_NOW | RTLD_GLOBAL - RTLD_NOW | RTLD_LOCAL I found the source code of dyld https://opensource.apple.com/source/dyld/dyld-852.2/ But I have no clue how to build this, I tried it but failed with missing dependencies. In any case, I provided a patch so at least we can use Guile on macOS. Best, Aleix On Sat, Sep 4, 2021 at 10:48 PM Aleix Conchillo Flaqué <aconchi...@gmail.com> wrote: > > Hi, > > I'm trying to load guile-grcypt with guile 3.0.7 and after my previous > fix > (https://git.savannah.gnu.org/cgit/guile.git/commit/?id=1f100a4f20c3a6e57922fb26fce212997e2a03cb) > guile-gcrypt still does not load properly. > > TLDR; Using RTLD_LOCAL instead of RTLD_GLOBAL (default) causes issues on > macOS. > > https://git.savannah.gnu.org/cgit/guile.git/tree/module/system/foreign-library.scm#n181 > > In the case of guile-gcrypt this is what I'm getting: > > ------------------------- > scheme@(guile-user)> (use-modules (gcrypt hmac)) > dyld: lazy symbol binding failed: Symbol not found: __gcry_check_version > Referenced from: /usr/local/lib/libgcrypt.dylib > Expected in: flat namespace > > dyld: Symbol not found: __gcry_check_version > Referenced from: /usr/local/lib/libgcrypt.dylib > Expected in: flat namespace > ------------------------- > > Looking at gcrypt symbols I can see: > > ❯ nm -gU /usr/local/lib/libgcrypt.dylib | grep gcry_check_version > 0000000000005954 T __gcry_check_version > 0000000000002aa7 T _gcry_check_version > > Actually in libgcrypt the public functions are: gcry_check_version and > _gcry_check_version (no extra underscore). I think extra underscores > are automatically added when building the library but I'm not sure why > and when and what systems. And when you call dlsym() you don't need to > add those extra underscores. > > The following code (which uses RTLD_GLOBAL) works fine: > > ./a.out gcry_check_version > > ------------------------- > #include <dlfcn.h> > #include <stdio.h> > > int > main(int argc, char *argv[]) > { > char* (*fptr)(char *); > void *handle = dlopen("/usr/local/lib/libgcrypt.dylib", RTLD_LAZY | > RTLD_GLOBAL); > if (handle == NULL) { > printf("OOOPS: %s\n", dlerror()); > } else { > *(void **)(&fptr) = dlsym(handle, argv[1]); > if (fptr == NULL) { > printf("NOT FOUND: %s : %s\n", argv[1], dlerror()); > } else { > printf("FOUND: %s %s\n", argv[1], (*fptr)(NULL)); > } > } > return 0; > } > ------------------------- > > But if we change to RTLD_LOCAL we get a crash like in guile's case. > > Sorry for being too vague but I'm not familiar with how all this > works. All I know is that using RTLD_GLOBAL fixes the issue. > > Also, from dlopen man page I read: > > ------------------------- > RTLD_GLOBAL Symbols exported from this image (dynamic library or > bundle) will be available to any images build with -flat_namespace > option to > ld(1) or to calls to dlsym() when using a special handle. > > RTLD_LOCAL Symbols exported from this image (dynamic library or > bundle) are generally hidden and only availble to dlsym() when > directly using > the handle returned by this call to dlopen(). > ------------------------- > > But I don't fully get what this means. > > Any help would be really appreciated. > > Thank you, > > Aleix
