upload android base code part3

android/bionic/linker/linker_block_allocator.cpp

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2014 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.
+ */
+
+#include "linker_block_allocator.h"
+#include <inttypes.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+#include "private/bionic_prctl.h"
+
+// the multiplier should be power of 2
+static constexpr size_t round_up(size_t size, size_t multiplier) {
+  return (size + (multiplier - 1)) & ~(multiplier-1);
+}
+
+struct LinkerBlockAllocatorPage {
+  LinkerBlockAllocatorPage* next;
+  uint8_t bytes[PAGE_SIZE - 16] __attribute__((aligned(16)));
+};
+
+struct FreeBlockInfo {
+  void* next_block;
+  size_t num_free_blocks;
+};
+
+LinkerBlockAllocator::LinkerBlockAllocator(size_t block_size)
+  : block_size_(
+      round_up(block_size < sizeof(FreeBlockInfo) ? sizeof(FreeBlockInfo) : block_size, 16)),
+    page_list_(nullptr),
+    free_block_list_(nullptr)
+{}
+
+void* LinkerBlockAllocator::alloc() {
+  if (free_block_list_ == nullptr) {
+    create_new_page();
+  }
+
+  FreeBlockInfo* block_info = reinterpret_cast<FreeBlockInfo*>(free_block_list_);
+  if (block_info->num_free_blocks > 1) {
+    FreeBlockInfo* next_block_info = reinterpret_cast<FreeBlockInfo*>(
+      reinterpret_cast<char*>(free_block_list_) + block_size_);
+    next_block_info->next_block = block_info->next_block;
+    next_block_info->num_free_blocks = block_info->num_free_blocks - 1;
+    free_block_list_ = next_block_info;
+  } else {
+    free_block_list_ = block_info->next_block;
+  }
+
+  memset(block_info, 0, block_size_);
+
+  return block_info;
+}
+
+void LinkerBlockAllocator::free(void* block) {
+  if (block == nullptr) {
+    return;
+  }
+
+  LinkerBlockAllocatorPage* page = find_page(block);
+
+  if (page == nullptr) {
+    abort();
+  }
+
+  ssize_t offset = reinterpret_cast<uint8_t*>(block) - page->bytes;
+
+  if (offset % block_size_ != 0) {
+    abort();
+  }
+
+  memset(block, 0, block_size_);
+
+  FreeBlockInfo* block_info = reinterpret_cast<FreeBlockInfo*>(block);
+
+  block_info->next_block = free_block_list_;
+  block_info->num_free_blocks = 1;
+
+  free_block_list_ = block_info;
+}
+
+void LinkerBlockAllocator::protect_all(int prot) {
+  for (LinkerBlockAllocatorPage* page = page_list_; page != nullptr; page = page->next) {
+    if (mprotect(page, PAGE_SIZE, prot) == -1) {
+      abort();
+    }
+  }
+}
+
+void LinkerBlockAllocator::create_new_page() {
+  static_assert(sizeof(LinkerBlockAllocatorPage) == PAGE_SIZE,
+                "Invalid sizeof(LinkerBlockAllocatorPage)");
+
+  LinkerBlockAllocatorPage* page = reinterpret_cast<LinkerBlockAllocatorPage*>(
+      mmap(nullptr, PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0));
+
+  if (page == MAP_FAILED) {
+    abort(); // oom
+  }
+
+  prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, page, PAGE_SIZE, "linker_alloc");
+
+  FreeBlockInfo* first_block = reinterpret_cast<FreeBlockInfo*>(page->bytes);
+  first_block->next_block = free_block_list_;
+  first_block->num_free_blocks = (PAGE_SIZE - sizeof(LinkerBlockAllocatorPage*))/block_size_;
+
+  free_block_list_ = first_block;
+
+  page->next = page_list_;
+  page_list_ = page;
+}
+
+LinkerBlockAllocatorPage* LinkerBlockAllocator::find_page(void* block) {
+  if (block == nullptr) {
+    abort();
+  }
+
+  LinkerBlockAllocatorPage* page = page_list_;
+  while (page != nullptr) {
+    const uint8_t* page_ptr = reinterpret_cast<const uint8_t*>(page);
+    if (block >= (page_ptr + sizeof(page->next)) && block < (page_ptr + PAGE_SIZE)) {
+      return page;
+    }
+
+    page = page->next;
+  }
+
+  abort();
+}