1 files changed, 185 insertions, 0 deletions
diff --git a/externals/breakpad/src/common/linux/elf_symbols_to_module.cc b/externals/breakpad/src/common/linux/elf_symbols_to_module.cc
new file mode 100644
index 0000000000..70d50f891e
--- /dev/null
+++ b/externals/breakpad/src/common/linux/elf_symbols_to_module.cc
@@ -0,0 +1,185 @@
+// -*- mode: c++ -*-
+
+// Copyright 2011 Google LLC
+//
+// 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.
+//     * Neither the name of Google LLC nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// 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.
+
+// Original author: Ted Mielczarek <ted.mielczarek@gmail.com>
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>  // Must come first
+#endif
+
+#include "common/linux/elf_symbols_to_module.h"
+
+#include <cxxabi.h>
+#include <elf.h>
+#include <string.h>
+
+#include <memory>
+#include <utility>
+
+#include "common/byte_cursor.h"
+#include "common/module.h"
+
+namespace google_breakpad {
+
+class ELFSymbolIterator {
+public:
+  // The contents of an ELF symbol, adjusted for the host's endianness,
+  // word size, and so on. Corresponds to the data in Elf32_Sym / Elf64_Sym.
+  struct Symbol {
+    // True if this iterator has reached the end of the symbol array. When
+    // this is set, the other members of this structure are not valid.
+    bool at_end;
+
+    // The number of this symbol within the list.
+    size_t index;
+
+    // The current symbol's name offset. This is the offset within the
+    // string table.
+    size_t name_offset;
+
+    // The current symbol's value, size, info and shndx fields.
+    uint64_t value;
+    uint64_t size;
+    unsigned char info;
+    uint16_t shndx;
+  };
+
+  // Create an ELFSymbolIterator walking the symbols in BUFFER. Treat the
+  // symbols as big-endian if BIG_ENDIAN is true, as little-endian
+  // otherwise. Assume each symbol has a 'value' field whose size is
+  // VALUE_SIZE.
+  //
+  ELFSymbolIterator(const ByteBuffer* buffer, bool big_endian,
+                    size_t value_size)
+    : value_size_(value_size), cursor_(buffer, big_endian) {
+    // Actually, weird sizes could be handled just fine, but they're
+    // probably mistakes --- expressed in bits, say.
+    assert(value_size == 4 || value_size == 8);
+    symbol_.index = 0;
+    Fetch();
+  }
+
+  // Move to the next symbol. This function's behavior is undefined if
+  // at_end() is true when it is called.
+  ELFSymbolIterator& operator++() { Fetch(); symbol_.index++; return *this; }
+
+  // Dereferencing this iterator produces a reference to an Symbol structure
+  // that holds the current symbol's values. The symbol is owned by this
+  // SymbolIterator, and will be invalidated at the next call to operator++.
+  const Symbol& operator*() const { return symbol_; }
+  const Symbol* operator->() const { return &symbol_; }
+
+private:
+  // Read the symbol at cursor_, and set symbol_ appropriately.
+  void Fetch() {
+    // Elf32_Sym and Elf64_Sym have different layouts.
+    unsigned char other;
+    if (value_size_ == 4) {
+      // Elf32_Sym
+      cursor_
+        .Read(4, false, &symbol_.name_offset)
+        .Read(4, false, &symbol_.value)
+        .Read(4, false, &symbol_.size)
+        .Read(1, false, &symbol_.info)
+        .Read(1, false, &other)
+        .Read(2, false, &symbol_.shndx);
+    } else {
+      // Elf64_Sym
+      cursor_
+        .Read(4, false, &symbol_.name_offset)
+        .Read(1, false, &symbol_.info)
+        .Read(1, false, &other)
+        .Read(2, false, &symbol_.shndx)
+        .Read(8, false, &symbol_.value)
+        .Read(8, false, &symbol_.size);
+    }
+    symbol_.at_end = !cursor_;
+  }
+
+  // The size of symbols' value field, in bytes.
+  size_t value_size_;
+
+  // A byte cursor traversing buffer_.
+  ByteCursor cursor_;
+
+  // Values for the symbol this iterator refers to.
+  Symbol symbol_;
+};
+
+const char* SymbolString(ptrdiff_t offset, ByteBuffer& strings) {
+  if (offset < 0 || (size_t) offset >= strings.Size()) {
+    // Return the null string.
+    offset = 0;
+  }
+  return reinterpret_cast<const char*>(strings.start + offset);
+}
+
+bool ELFSymbolsToModule(const uint8_t* symtab_section,
+                        size_t symtab_size,
+                        const uint8_t* string_section,
+                        size_t string_size,
+                        const bool big_endian,
+                        size_t value_size,
+                        Module* module) {
+  ByteBuffer symbols(symtab_section, symtab_size);
+  // Ensure that the string section is null-terminated.
+  if (string_section[string_size - 1] != '\0') {
+    const void* null_terminator = memrchr(string_section, '\0', string_size);
+    string_size = reinterpret_cast<const uint8_t*>(null_terminator)
+      - string_section;
+  }
+  ByteBuffer strings(string_section, string_size);
+
+  // The iterator walking the symbol table.
+  ELFSymbolIterator iterator(&symbols, big_endian, value_size);
+
+  while(!iterator->at_end) {
+    if (ELF32_ST_TYPE(iterator->info) == STT_FUNC &&
+        iterator->shndx != SHN_UNDEF) {
+      auto ext = std::make_unique<Module::Extern>(iterator->value);
+      ext->name = SymbolString(iterator->name_offset, strings);
+#if !defined(__ANDROID__)  // Android NDK doesn't provide abi::__cxa_demangle.
+      int status = 0;
+      char* demangled =
+          abi::__cxa_demangle(ext->name.c_str(), NULL, NULL, &status);
+      if (demangled) {
+        if (status == 0)
+          ext->name = demangled;
+        free(demangled);
+      }
+#endif
+      module->AddExtern(std::move(ext));
+    }
+    ++iterator;
+  }
+  return true;
+}
+
+}  // namespace google_breakpad