engine: android: restore dlsym hack for old Android(<5.0)

engine/platform/android/dlsym-weak.cpp

@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2008, 2009 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifdef __ANDROID__
+#include <android/log.h>
+#include "linker.h"
+
+static Elf_Sym* soinfo_elf_lookup(soinfo* si, unsigned hash, const char* name) {
+    Elf_Sym* symtab = si->symtab;
+    const char* strtab = si->strtab;
+
+    for (unsigned n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]) {
+        Elf_Sym* s = symtab + n;
+        if (strcmp(strtab + s->st_name, name)) continue;
+
+            /* only concern ourselves with global and weak symbol definitions */
+        switch (ELF_ST_BIND(s->st_info)) {
+        case STB_GLOBAL:
+        case STB_WEAK:
+            if (s->st_shndx == SHN_UNDEF) {
+                continue;
+            }
+            return s;
+        }
+    }
+
+    return NULL;
+}
+
+static unsigned elfhash(const char* _name) {
+    const unsigned char* name = (const unsigned char*) _name;
+    unsigned h = 0, g;
+
+    while(*name) {
+        h = (h << 4) + *name++;
+        g = h & 0xf0000000;
+        h ^= g;
+        h ^= g >> 24;
+    }
+    return h;
+}
+
+/* This is used by dlsym(3).  It performs symbol lookup only within the
+   specified soinfo object and not in any of its dependencies.
+
+   TODO: Only looking in the specified soinfo seems wrong. dlsym(3) says
+   that it should do a breadth first search through the dependency
+   tree. This agrees with the ELF spec (aka System V Application
+   Binary Interface) where in Chapter 5 it discuss resolving "Shared
+   Object Dependencies" in breadth first search order.
+ */
+Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name) {
+    return soinfo_elf_lookup(si, elfhash(name), name);
+}
+
+extern "C" void* dlsym_weak(void* handle, const char* symbol) {
+
+  soinfo* found = NULL;
+  Elf_Sym* sym = NULL;
+  found = reinterpret_cast<soinfo*>(handle);
+  sym = dlsym_handle_lookup(found, symbol);
+
+  if (sym != NULL) {
+    return reinterpret_cast<void*>(sym->st_value + found->base/*load_bias*/);
+  }
+  __android_log_print(ANDROID_LOG_ERROR, "dlsym-weak", "Failed when looking up %s\n", symbol);
+  return NULL;
+}
+#endif

engine/platform/android/dlsym-weak.h

@@ -0,0 +1,21 @@
+/*
+dlsym-weak.h -- custom dlsym() function to override bionic libc bug on Android <5.0
+Copyright (C) 2015-2017 Flying With Gauss
+
+This program 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 of the License, or
+(at your option) any later version.
+
+This program 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.
+*/
+#ifndef DLSYM_WEAH_H
+#define DLSYM_WEAK_H
+
+// ------------ dlsym-weak.cpp ------------ //
+void* dlsym_weak(void* handle, const char* symbol);
+
+#endif

engine/platform/android/lib_android.c

@@ -18,8 +18,8 @@ GNU General Public License for more details.
 #include "library.h"
 #include "filesystem.h"
 #include "server.h"
-#include "platform/android/android_lib.h"
+#include "platform/android/lib_android.h"
-#include "platform/android/dlsym_weak.h" // Android < 5.0
+#include "platform/android/dlsym-weak.h" // Android < 5.0
 
 void *ANDROID_LoadLibrary( const char *dllname )
 {

engine/platform/android/linker.h

@@ -0,0 +1,202 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef _LINKER_H_
+#define _LINKER_H_
+#ifdef __ANDROID__
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <elf.h>
+#include <sys/exec_elf.h>
+
+#include <link.h>
+
+// Returns the address of the page containing address 'x'.
+#define PAGE_START(x)  ((x) & PAGE_MASK)
+
+// Returns the offset of address 'x' in its page.
+#define PAGE_OFFSET(x) ((x) & ~PAGE_MASK)
+
+// Returns the address of the next page after address 'x', unless 'x' is
+// itself at the start of a page.
+#define PAGE_END(x)    PAGE_START((x) + (PAGE_SIZE-1))
+
+// Magic shared structures that GDB knows about.
+
+struct link_map_t {
+  uintptr_t l_addr;
+  char*  l_name;
+  uintptr_t l_ld;
+  link_map_t* l_next;
+  link_map_t* l_prev;
+};
+
+// Values for r_debug->state
+enum {
+  RT_CONSISTENT,
+  RT_ADD,
+  RT_DELETE
+};
+#if 0
+struct r_debug {
+  int32_t r_version;
+  link_map_t* r_map;
+  void (*r_brk)(void);
+  int32_t r_state;
+  uintptr_t r_ldbase;
+};
+#endif
+#define FLAG_LINKED     0x00000001
+#define FLAG_EXE        0x00000004 // The main executable
+#define FLAG_LINKER     0x00000010 // The linker itself
+
+#define SOINFO_NAME_LEN 128
+
+typedef void (*linker_function_t)();
+
+// Android uses REL for 32-bit but only uses RELA for 64-bit.
+#if defined(__LP64__)
+#define USE_RELA 1
+#endif
+
+struct soinfo {
+ public:
+  char name[SOINFO_NAME_LEN];
+  const Elf_Phdr* phdr;
+  size_t phnum;
+  Elf_Addr entry;
+  Elf_Addr base;
+  unsigned size;
+
+#ifndef __LP64__
+  uint32_t unused1;  // DO NOT USE, maintained for compatibility.
+#endif
+
+  Elf_Dyn* dynamic;
+
+#ifndef __LP64__
+  uint32_t unused2; // DO NOT USE, maintained for compatibility
+  uint32_t unused3; // DO NOT USE, maintained for compatibility
+#endif
+
+  soinfo* next;
+  unsigned flags;
+
+  const char* strtab;
+  Elf_Sym* symtab;
+
+  size_t nbucket;
+  size_t nchain;
+  unsigned* bucket;
+  unsigned* chain;
+
+#if !defined(__LP64__)
+  // This is only used by 32-bit MIPS, but needs to be here for
+  // all 32-bit architectures to preserve binary compatibility.
+  unsigned* plt_got;
+#endif
+
+#if defined(USE_RELA)
+  Elf_Rela* plt_rela;
+  size_t plt_rela_count;
+
+  Elf_Rela* rela;
+  size_t rela_count;
+#else
+  Elf_Rel* plt_rel;
+  size_t plt_rel_count;
+
+  Elf_Rel* rel;
+  size_t rel_count;
+#endif
+
+  linker_function_t* preinit_array;
+  size_t preinit_array_count;
+
+  linker_function_t* init_array;
+  size_t init_array_count;
+  linker_function_t* fini_array;
+  size_t fini_array_count;
+
+  linker_function_t init_func;
+  linker_function_t fini_func;
+
+#if defined(__arm__)
+  // ARM EABI section used for stack unwinding.
+  unsigned* ARM_exidx;
+  size_t ARM_exidx_count;
+#elif defined(__mips__)
+  unsigned mips_symtabno;
+  unsigned mips_local_gotno;
+  unsigned mips_gotsym;
+#endif
+
+  size_t ref_count;
+  link_map_t link_map;
+
+  bool constructors_called;
+
+  // When you read a virtual address from the ELF file, add this
+  // value to get the corresponding address in the process' address space.
+  Elf_Addr load_bias;
+
+#if !defined(__LP64__)
+  bool has_text_relocations;
+#endif
+  bool has_DT_SYMBOLIC;
+
+  void CallConstructors();
+  void CallDestructors();
+  void CallPreInitConstructors();
+
+ private:
+  void CallArray(const char* array_name, linker_function_t* functions, size_t count, bool reverse);
+  void CallFunction(const char* function_name, linker_function_t function);
+};
+
+extern soinfo libdl_info;
+
+void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);
+soinfo* do_dlopen(const char* name, int flags);
+int do_dlclose(soinfo* si);
+
+Elf_Sym* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start);
+soinfo* find_containing_library(const void* addr);
+
+Elf_Sym* dladdr_find_symbol(soinfo* si, const void* addr);
+Elf_Sym* dlsym_handle_lookup(soinfo* si, const char* name);
+
+void debuggerd_init();
+extern "C" void notify_gdb_of_libraries();
+
+char* linker_get_error_buffer();
+size_t linker_get_error_buffer_size();
+
+#endif
+#endif