| // MACHO-specific support for sections. |
| // Copyright (C) 2021 Free Software Foundation, Inc. |
| |
| // GCC is free software; you can redistribute it and/or modify it under |
| // the terms of the GNU General Public License as published by the Free |
| // Software Foundation; either version 3, or (at your option) any later |
| // version. |
| |
| // GCC is distributed in the hope that it will be useful, but WITHOUT ANY |
| // WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| // FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| // for more details. |
| |
| // Under Section 7 of GPL version 3, you are granted additional |
| // permissions described in the GCC Runtime Library Exception, version |
| // 3.1, as published by the Free Software Foundation. |
| |
| // You should have received a copy of the GNU General Public License and |
| // a copy of the GCC Runtime Library Exception along with this program; |
| // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
| // <http://www.gnu.org/licenses/>. |
| |
| module gcc.sections.macho; |
| |
| version (OSX): |
| |
| import core.memory; |
| import core.stdc.stdlib; |
| import core.sys.darwin.dlfcn; |
| import core.sys.darwin.mach.dyld; |
| import core.sys.darwin.mach.getsect; |
| import core.sys.posix.pthread; |
| import rt.minfo; |
| import rt.util.container.array; |
| import rt.util.container.hashtab; |
| import gcc.sections.common; |
| |
| version (GNU_EMUTLS) |
| import gcc.emutls; |
| |
| alias DSO SectionGroup; |
| struct DSO |
| { |
| static int opApply(scope int delegate(ref DSO) dg) |
| { |
| foreach (dso; _loadedDSOs) |
| { |
| if (auto res = dg(*dso)) |
| return res; |
| } |
| return 0; |
| } |
| |
| static int opApplyReverse(scope int delegate(ref DSO) dg) |
| { |
| foreach_reverse (dso; _loadedDSOs) |
| { |
| if (auto res = dg(*dso)) |
| return res; |
| } |
| return 0; |
| } |
| |
| @property immutable(ModuleInfo*)[] modules() const nothrow @nogc |
| { |
| return _moduleGroup.modules; |
| } |
| |
| @property ref inout(ModuleGroup) moduleGroup() inout nothrow @nogc |
| { |
| return _moduleGroup; |
| } |
| |
| @property inout(void[])[] gcRanges() inout nothrow @nogc |
| { |
| return _gcRanges[]; |
| } |
| |
| private: |
| |
| invariant() |
| { |
| safeAssert(_moduleGroup.modules.length > 0, "No modules for DSO."); |
| } |
| |
| void** _slot; |
| ModuleGroup _moduleGroup; |
| Array!(void[]) _gcRanges; |
| |
| version (Shared) |
| { |
| Array!(void[]) _codeSegments; // array of code segments |
| Array!(DSO*) _deps; // D libraries needed by this DSO |
| void* _handle; // corresponding handle |
| } |
| } |
| |
| /**** |
| * Boolean flag set to true while the runtime is initialized. |
| */ |
| __gshared bool _isRuntimeInitialized; |
| |
| /**** |
| * Gets called on program startup just before GC is initialized. |
| */ |
| void initSections() nothrow @nogc |
| { |
| _isRuntimeInitialized = true; |
| } |
| |
| /*** |
| * Gets called on program shutdown just after GC is terminated. |
| */ |
| void finiSections() nothrow @nogc |
| { |
| _isRuntimeInitialized = false; |
| } |
| |
| alias ScanDG = void delegate(void* pbeg, void* pend) nothrow; |
| |
| version (Shared) |
| { |
| import gcc.sections : pinLoadedLibraries, unpinLoadedLibraries, |
| inheritLoadedLibraries, cleanupLoadedLibraries; |
| |
| /*** |
| * Called once per thread; returns array of thread local storage ranges |
| */ |
| Array!(ThreadDSO)* initTLSRanges() @nogc nothrow |
| { |
| return &_loadedDSOs(); |
| } |
| |
| void finiTLSRanges(Array!(ThreadDSO)* tdsos) @nogc nothrow |
| { |
| // Nothing to do here. tdsos used to point to the _loadedDSOs instance |
| // in the dying thread's TLS segment and as such is not valid anymore. |
| // The memory for the array contents was already reclaimed in |
| // cleanupLoadedLibraries(). |
| } |
| |
| void scanTLSRanges(Array!(ThreadDSO)* tdsos, scope ScanDG dg) nothrow |
| { |
| version (GNU_EMUTLS) |
| _d_emutls_scan(dg); |
| else |
| static assert(0, "Native TLS unimplemented"); |
| } |
| |
| // interface for core.thread to inherit loaded libraries |
| pragma(mangle, gcc.sections.pinLoadedLibraries.mangleof) |
| void* pinLoadedLibraries() nothrow @nogc |
| { |
| auto res = cast(Array!(ThreadDSO)*)calloc(1, Array!(ThreadDSO).sizeof); |
| res.length = _loadedDSOs.length; |
| foreach (i, ref tdso; _loadedDSOs) |
| { |
| (*res)[i] = tdso; |
| if (tdso._addCnt) |
| { |
| // Increment the dlopen ref for explicitly loaded libraries to pin them. |
| const success = .dlopen(nameForDSO(tdso._pdso), RTLD_LAZY) !is null; |
| safeAssert(success, "Failed to increment dlopen ref."); |
| (*res)[i]._addCnt = 1; // new array takes over the additional ref count |
| } |
| } |
| return res; |
| } |
| |
| pragma(mangle, gcc.sections.unpinLoadedLibraries.mangleof) |
| void unpinLoadedLibraries(void* p) nothrow @nogc |
| { |
| auto pary = cast(Array!(ThreadDSO)*)p; |
| // In case something failed we need to undo the pinning. |
| foreach (ref tdso; *pary) |
| { |
| if (tdso._addCnt) |
| { |
| auto handle = tdso._pdso._handle; |
| safeAssert(handle !is null, "Invalid library handle."); |
| .dlclose(handle); |
| } |
| } |
| pary.reset(); |
| .free(pary); |
| } |
| |
| // Called before TLS ctors are ran, copy over the loaded libraries |
| // of the parent thread. |
| pragma(mangle, gcc.sections.inheritLoadedLibraries.mangleof) |
| void inheritLoadedLibraries(void* p) nothrow @nogc |
| { |
| safeAssert(_loadedDSOs.empty, "DSOs have already been registered for this thread."); |
| _loadedDSOs.swap(*cast(Array!(ThreadDSO)*)p); |
| .free(p); |
| } |
| |
| // Called after all TLS dtors ran, decrements all remaining dlopen refs. |
| pragma(mangle, gcc.sections.cleanupLoadedLibraries.mangleof) |
| void cleanupLoadedLibraries() nothrow @nogc |
| { |
| foreach (ref tdso; _loadedDSOs) |
| { |
| if (tdso._addCnt == 0) continue; |
| |
| auto handle = tdso._pdso._handle; |
| safeAssert(handle !is null, "Invalid DSO handle."); |
| for (; tdso._addCnt > 0; --tdso._addCnt) |
| .dlclose(handle); |
| } |
| |
| // Free the memory for the array contents. |
| _loadedDSOs.reset(); |
| } |
| } |
| else |
| { |
| /*** |
| * Called once per thread; returns array of thread local storage ranges |
| */ |
| Array!(void[])* initTLSRanges() nothrow @nogc |
| { |
| return null; |
| } |
| |
| void finiTLSRanges(Array!(void[])* rngs) nothrow @nogc |
| { |
| } |
| |
| void scanTLSRanges(Array!(void[])* rngs, scope ScanDG dg) nothrow |
| { |
| version (GNU_EMUTLS) |
| _d_emutls_scan(dg); |
| else |
| static assert(0, "Native TLS unimplemented"); |
| } |
| } |
| |
| private: |
| |
| version (Shared) |
| { |
| /* |
| * Array of thread local DSO metadata for all libraries loaded and |
| * initialized in this thread. |
| * |
| * Note: |
| * A newly spawned thread will inherit these libraries. |
| * Note: |
| * We use an array here to preserve the order of |
| * initialization. If that became a performance issue, we |
| * could use a hash table and enumerate the DSOs during |
| * loading so that the hash table values could be sorted when |
| * necessary. |
| */ |
| struct ThreadDSO |
| { |
| DSO* _pdso; |
| static if (_pdso.sizeof == 8) uint _refCnt, _addCnt; |
| else static if (_pdso.sizeof == 4) ushort _refCnt, _addCnt; |
| else static assert(0, "unimplemented"); |
| alias _pdso this; |
| } |
| |
| @property ref Array!(ThreadDSO) _loadedDSOs() @nogc nothrow |
| { |
| static Array!(ThreadDSO) x; |
| return x; |
| } |
| |
| /* |
| * Set to true during rt_loadLibrary/rt_unloadLibrary calls. |
| */ |
| bool _rtLoading; |
| |
| /* |
| * Hash table to map the native handle (as returned by dlopen) |
| * to the corresponding DSO*, protected by a mutex. |
| */ |
| __gshared pthread_mutex_t _handleToDSOMutex; |
| @property ref HashTab!(void*, DSO*) _handleToDSO() @nogc nothrow |
| { |
| __gshared HashTab!(void*, DSO*) x; |
| return x; |
| } |
| } |
| else |
| { |
| /* |
| * Static DSOs loaded by the runtime linker. This includes the |
| * executable. These can't be unloaded. |
| */ |
| @property ref Array!(DSO*) _loadedDSOs() @nogc nothrow |
| { |
| __gshared Array!(DSO*) x; |
| return x; |
| } |
| |
| enum _rtLoading = false; |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Compiler to runtime interface. |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| struct MachHeader |
| { |
| const(mach_header)* header; // the mach header of the image |
| intptr_t slide; // virtural memory address slide amount |
| } |
| |
| /**** |
| * This data structure is generated by the compiler, and then passed to |
| * _d_dso_registry(). |
| */ |
| struct CompilerDSOData |
| { |
| size_t _version; // currently 1 |
| void** _slot; // can be used to store runtime data |
| immutable(object.ModuleInfo*)* _minfo_beg, _minfo_end; // array of modules in this object file |
| } |
| |
| T[] toRange(T)(T* beg, T* end) { return beg[0 .. end - beg]; } |
| |
| /* For each shared library and executable, the compiler generates code that |
| * sets up CompilerDSOData and calls _d_dso_registry(). |
| * A pointer to that code is inserted into both the .ctors and .dtors |
| * segment so it gets called by the loader on startup and shutdown. |
| */ |
| extern(C) void _d_dso_registry(CompilerDSOData* data) |
| { |
| // only one supported currently |
| safeAssert(data._version >= 1, "Incompatible compiler-generated DSO data version."); |
| |
| // no backlink => register |
| if (*data._slot is null) |
| { |
| immutable firstDSO = _loadedDSOs.empty; |
| if (firstDSO) initLocks(); |
| |
| DSO* pdso = cast(DSO*).calloc(1, DSO.sizeof); |
| assert(typeid(DSO).initializer().ptr is null); |
| pdso._slot = data._slot; |
| *data._slot = pdso; // store backlink in library record |
| |
| pdso._moduleGroup = ModuleGroup(toRange(data._minfo_beg, data._minfo_end)); |
| |
| MachHeader header = void; |
| const headerFound = findImageHeaderForAddr(data._slot, header); |
| safeAssert(headerFound, "Failed to find image header."); |
| |
| scanSegments(header, pdso); |
| |
| version (Shared) |
| { |
| auto handle = handleForAddr(data._slot); |
| |
| getDependencies(header, pdso._deps); |
| pdso._handle = handle; |
| setDSOForHandle(pdso, pdso._handle); |
| |
| if (!_rtLoading) |
| { |
| /* This DSO was not loaded by rt_loadLibrary which |
| * happens for all dependencies of an executable or |
| * the first dlopen call from a C program. |
| * In this case we add the DSO to the _loadedDSOs of this |
| * thread with a refCnt of 1 and call the TlsCtors. |
| */ |
| immutable ushort refCnt = 1, addCnt = 0; |
| _loadedDSOs.insertBack(ThreadDSO(pdso, refCnt, addCnt)); |
| } |
| } |
| else |
| { |
| foreach (p; _loadedDSOs) |
| safeAssert(p !is pdso, "DSO already registered."); |
| _loadedDSOs.insertBack(pdso); |
| } |
| |
| // don't initialize modules before rt_init was called |
| if (_isRuntimeInitialized) |
| { |
| registerGCRanges(pdso); |
| // rt_loadLibrary will run tls ctors, so do this only for dlopen |
| immutable runTlsCtors = !_rtLoading; |
| runModuleConstructors(pdso, runTlsCtors); |
| } |
| } |
| // has backlink => unregister |
| else |
| { |
| DSO* pdso = cast(DSO*)*data._slot; |
| *data._slot = null; |
| |
| // don't finalizes modules after rt_term was called (see Bugzilla 11378) |
| if (_isRuntimeInitialized) |
| { |
| // rt_unloadLibrary already ran tls dtors, so do this only for dlclose |
| immutable runTlsDtors = !_rtLoading; |
| runModuleDestructors(pdso, runTlsDtors); |
| unregisterGCRanges(pdso); |
| // run finalizers after module dtors (same order as in rt_term) |
| version (Shared) runFinalizers(pdso); |
| } |
| |
| version (Shared) |
| { |
| if (!_rtLoading) |
| { |
| /* This DSO was not unloaded by rt_unloadLibrary so we |
| * have to remove it from _loadedDSOs here. |
| */ |
| foreach (i, ref tdso; _loadedDSOs) |
| { |
| if (tdso._pdso == pdso) |
| { |
| _loadedDSOs.remove(i); |
| break; |
| } |
| } |
| } |
| |
| unsetDSOForHandle(pdso, pdso._handle); |
| } |
| else |
| { |
| // static DSOs are unloaded in reverse order |
| safeAssert(pdso == _loadedDSOs.back, "DSO being unregistered isn't current last one."); |
| _loadedDSOs.popBack(); |
| } |
| |
| freeDSO(pdso); |
| |
| // last DSO being unloaded => shutdown registry |
| if (_loadedDSOs.empty) |
| { |
| version (GNU_EMUTLS) |
| _d_emutls_destroy(); |
| version (Shared) |
| { |
| safeAssert(_handleToDSO.empty, "_handleToDSO not in sync with _loadedDSOs."); |
| _handleToDSO.reset(); |
| } |
| finiLocks(); |
| } |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // dynamic loading |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| // Shared D libraries are only supported when linking against a shared druntime library. |
| |
| version (Shared) |
| { |
| ThreadDSO* findThreadDSO(DSO* pdso) nothrow @nogc |
| { |
| foreach (ref tdata; _loadedDSOs) |
| if (tdata._pdso == pdso) return &tdata; |
| return null; |
| } |
| |
| void incThreadRef(DSO* pdso, bool incAdd) |
| { |
| if (auto tdata = findThreadDSO(pdso)) // already initialized |
| { |
| if (incAdd && ++tdata._addCnt > 1) return; |
| ++tdata._refCnt; |
| } |
| else |
| { |
| foreach (dep; pdso._deps) |
| incThreadRef(dep, false); |
| immutable ushort refCnt = 1, addCnt = incAdd ? 1 : 0; |
| _loadedDSOs.insertBack(ThreadDSO(pdso, refCnt, addCnt)); |
| pdso._moduleGroup.runTlsCtors(); |
| } |
| } |
| |
| void decThreadRef(DSO* pdso, bool decAdd) |
| { |
| auto tdata = findThreadDSO(pdso); |
| safeAssert(tdata !is null, "Failed to find thread DSO."); |
| safeAssert(!decAdd || tdata._addCnt > 0, "Mismatching rt_unloadLibrary call."); |
| |
| if (decAdd && --tdata._addCnt > 0) return; |
| if (--tdata._refCnt > 0) return; |
| |
| pdso._moduleGroup.runTlsDtors(); |
| foreach (i, ref td; _loadedDSOs) |
| if (td._pdso == pdso) _loadedDSOs.remove(i); |
| foreach (dep; pdso._deps) |
| decThreadRef(dep, false); |
| } |
| |
| extern(C) void* rt_loadLibrary(const char* name) |
| { |
| immutable save = _rtLoading; |
| _rtLoading = true; |
| scope (exit) _rtLoading = save; |
| |
| auto handle = .dlopen(name, RTLD_LAZY); |
| if (handle is null) return null; |
| |
| // if it's a D library |
| if (auto pdso = dsoForHandle(handle)) |
| incThreadRef(pdso, true); |
| return handle; |
| } |
| |
| extern(C) int rt_unloadLibrary(void* handle) |
| { |
| if (handle is null) return false; |
| |
| immutable save = _rtLoading; |
| _rtLoading = true; |
| scope (exit) _rtLoading = save; |
| |
| // if it's a D library |
| if (auto pdso = dsoForHandle(handle)) |
| decThreadRef(pdso, true); |
| return .dlclose(handle) == 0; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // helper functions |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| void initLocks() nothrow @nogc |
| { |
| version (Shared) |
| !pthread_mutex_init(&_handleToDSOMutex, null) || assert(0); |
| } |
| |
| void finiLocks() nothrow @nogc |
| { |
| version (Shared) |
| !pthread_mutex_destroy(&_handleToDSOMutex) || assert(0); |
| } |
| |
| void runModuleConstructors(DSO* pdso, bool runTlsCtors) |
| { |
| pdso._moduleGroup.sortCtors(); |
| pdso._moduleGroup.runCtors(); |
| if (runTlsCtors) pdso._moduleGroup.runTlsCtors(); |
| } |
| |
| void runModuleDestructors(DSO* pdso, bool runTlsDtors) |
| { |
| if (runTlsDtors) pdso._moduleGroup.runTlsDtors(); |
| pdso._moduleGroup.runDtors(); |
| } |
| |
| void registerGCRanges(DSO* pdso) nothrow @nogc |
| { |
| foreach (rng; pdso._gcRanges) |
| GC.addRange(rng.ptr, rng.length); |
| } |
| |
| void unregisterGCRanges(DSO* pdso) nothrow @nogc |
| { |
| foreach (rng; pdso._gcRanges) |
| GC.removeRange(rng.ptr); |
| } |
| |
| version (Shared) void runFinalizers(DSO* pdso) |
| { |
| foreach (seg; pdso._codeSegments) |
| GC.runFinalizers(seg); |
| } |
| |
| void freeDSO(DSO* pdso) nothrow @nogc |
| { |
| pdso._gcRanges.reset(); |
| version (Shared) |
| { |
| pdso._codeSegments.reset(); |
| pdso._deps.reset(); |
| pdso._handle = null; |
| } |
| .free(pdso); |
| } |
| |
| version (Shared) |
| { |
| @nogc nothrow: |
| const(char)* nameForDSO(in DSO* pdso) |
| { |
| Dl_info info = void; |
| const success = dladdr(pdso._slot, &info) != 0; |
| safeAssert(success, "Failed to get DSO info."); |
| return info.dli_fname; |
| } |
| |
| DSO* dsoForHandle(void* handle) |
| { |
| DSO* pdso; |
| !pthread_mutex_lock(&_handleToDSOMutex) || assert(0); |
| if (auto ppdso = handle in _handleToDSO) |
| pdso = *ppdso; |
| !pthread_mutex_unlock(&_handleToDSOMutex) || assert(0); |
| return pdso; |
| } |
| |
| void setDSOForHandle(DSO* pdso, void* handle) |
| { |
| !pthread_mutex_lock(&_handleToDSOMutex) || assert(0); |
| safeAssert(handle !in _handleToDSO, "DSO already registered."); |
| _handleToDSO[handle] = pdso; |
| !pthread_mutex_unlock(&_handleToDSOMutex) || assert(0); |
| } |
| |
| void unsetDSOForHandle(DSO* pdso, void* handle) |
| { |
| !pthread_mutex_lock(&_handleToDSOMutex) || assert(0); |
| safeAssert(_handleToDSO[handle] == pdso, "Handle doesn't match registered DSO."); |
| _handleToDSO.remove(handle); |
| !pthread_mutex_unlock(&_handleToDSOMutex) || assert(0); |
| } |
| |
| void getDependencies(in MachHeader info, ref Array!(DSO*) deps) |
| { |
| // FIXME: Not implemented yet. |
| } |
| |
| void* handleForName(const char* name) |
| { |
| auto handle = .dlopen(name, RTLD_NOLOAD | RTLD_LAZY); |
| if (handle !is null) .dlclose(handle); // drop reference count |
| return handle; |
| } |
| } |
| |
| /////////////////////////////////////////////////////////////////////////////// |
| // Mach-O program header iteration |
| /////////////////////////////////////////////////////////////////////////////// |
| |
| /************ |
| * Scan segments in the image header and store |
| * the writeable data segments in *pdso. |
| */ |
| |
| void scanSegments(in MachHeader info, DSO* pdso) |
| { |
| foreach (e; dataSegs) |
| { |
| auto sect = getSection(info.header, info.slide, e.seg.ptr, e.sect.ptr); |
| if (sect != null) |
| pdso._gcRanges.insertBack((cast(void*)sect.ptr)[0 .. sect.length]); |
| } |
| |
| version (Shared) |
| { |
| void[] text = getSection(info.header, info.slide, "__TEXT", "__text"); |
| if (!text) |
| assert(0, "Failed to get text section."); |
| pdso._codeSegments.insertBack(text); |
| } |
| } |
| |
| /************************** |
| * Input: |
| * result where the output is to be written |
| * Returns: |
| * true if found, and *result is filled in |
| */ |
| |
| bool findImageHeaderForAddr(in void* addr, out MachHeader result) |
| { |
| Dl_info info; |
| if (dladdr(addr, &info) == 0) |
| return false; |
| |
| foreach (i; 0 .. _dyld_image_count()) |
| { |
| if (info.dli_fbase == _dyld_get_image_header(i)) |
| { |
| result.header = cast(const(mach_header)*)info.dli_fbase; |
| result.slide = _dyld_get_image_vmaddr_slide(i); |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /************************** |
| * Input: |
| * addr an internal address of a DSO |
| * Returns: |
| * the dlopen handle for that DSO or null if addr is not within a loaded DSO |
| */ |
| version (Shared) void* handleForAddr(void* addr) nothrow @nogc |
| { |
| Dl_info info = void; |
| if (dladdr(addr, &info) != 0) |
| return handleForName(info.dli_fname); |
| return null; |
| } |
| |
| struct SegRef |
| { |
| string seg; |
| string sect; |
| } |
| |
| static immutable SegRef[] dataSegs = [{SEG_DATA, SECT_DATA}, |
| {SEG_DATA, SECT_BSS}, |
| {SEG_DATA, SECT_COMMON}]; |
| |
| /** |
| * Returns the section for the named section in the named segment |
| * for the mach_header pointer passed, or null if not found. |
| */ |
| ubyte[] getSection(in mach_header* header, intptr_t slide, |
| in char* segmentName, in char* sectionName) |
| { |
| version (D_LP64) |
| { |
| assert(header.magic == MH_MAGIC_64); |
| auto sect = getsectbynamefromheader_64(cast(mach_header_64*)header, |
| segmentName, |
| sectionName); |
| } |
| else |
| { |
| assert(header.magic == MH_MAGIC); |
| auto sect = getsectbynamefromheader(header, |
| segmentName, |
| sectionName); |
| } |
| |
| if (sect !is null && sect.size > 0) |
| return (cast(ubyte*)sect.addr + slide)[0 .. cast(size_t)sect.size]; |
| return null; |
| } |