1 files changed, 363 insertions, 0 deletions
diff --git a/Source/cmMachO.cxx b/Source/cmMachO.cxx
new file mode 100644
index 000000000..a4350f7ce
--- /dev/null
+++ b/Source/cmMachO.cxx
@@ -0,0 +1,363 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmMachO.h"
+
+#include "cmsys/FStream.hxx"
+#include <algorithm>
+#include <stddef.h>
+#include <string>
+#include <vector>
+
+// Include the Mach-O format information system header.
+#include <mach-o/fat.h>
+#include <mach-o/loader.h>
+
+/**
+
+  https://developer.apple.com/library/mac/documentation/
+          DeveloperTools/Conceptual/MachORuntime/index.html
+
+  A Mach-O file has 3 major regions: header, load commands and segments.
+  Data Structures are provided from <mach-o/loader.h> which
+  correspond to the file structure.
+
+  The header can be either a struct mach_header or struct mach_header_64.
+  One can peek at the first 4 bytes to identify the type of header.
+
+  Following is the load command region which starts with
+  struct load_command, and is followed by n number of load commands.
+
+  In the case of a universal binary (an archive of multiple Mach-O files),
+  the file begins with a struct fat_header and is followed by multiple
+  struct fat_arch instances.  The struct fat_arch indicates the offset
+  for each Mach-O file.
+
+  */
+
+namespace {
+
+// peek in the file
+template <typename T>
+bool peek(cmsys::ifstream& fin, T& v)
+{
+  std::streampos p = fin.tellg();
+  if (!fin.read(reinterpret_cast<char*>(&v), sizeof(T))) {
+    return false;
+  }
+  fin.seekg(p);
+  return fin.good();
+}
+
+// read from the file and fill a data structure
+template <typename T>
+bool read(cmsys::ifstream& fin, T& v)
+{
+  if (!fin.read(reinterpret_cast<char*>(&v), sizeof(T))) {
+    return false;
+  }
+  return true;
+}
+
+// read from the file and fill multiple data structures where
+// the vector has been resized
+template <typename T>
+bool read(cmsys::ifstream& fin, std::vector<T>& v)
+{
+  // nothing to read
+  if (v.empty()) {
+    return true;
+  }
+  if (!fin.read(reinterpret_cast<char*>(&v[0]), sizeof(T) * v.size())) {
+    return false;
+  }
+  return true;
+}
+}
+
+// Contains header and load commands for a single Mach-O file
+class cmMachOHeaderAndLoadCommands
+{
+public:
+  // A load_command and its associated data
+  struct RawLoadCommand
+  {
+    uint32_t type(const cmMachOHeaderAndLoadCommands* m) const
+    {
+      if (this->LoadCommand.size() < sizeof(load_command)) {
+        return 0;
+      }
+      const load_command* cmd =
+        reinterpret_cast<const load_command*>(&this->LoadCommand[0]);
+      return m->swap(cmd->cmd);
+    }
+    std::vector<char> LoadCommand;
+  };
+
+  cmMachOHeaderAndLoadCommands(bool _swap)
+    : Swap(_swap)
+  {
+  }
+  virtual ~cmMachOHeaderAndLoadCommands() {}
+
+  virtual bool read_mach_o(cmsys::ifstream& fin) = 0;
+
+  const std::vector<RawLoadCommand>& load_commands() const
+  {
+    return this->LoadCommands;
+  }
+
+  uint32_t swap(uint32_t v) const
+  {
+    if (this->Swap) {
+      char* c = reinterpret_cast<char*>(&v);
+      std::swap(c[0], c[3]);
+      std::swap(c[1], c[2]);
+    }
+    return v;
+  }
+
+protected:
+  bool read_load_commands(uint32_t ncmds, uint32_t sizeofcmds,
+                          cmsys::ifstream& fin);
+
+  bool Swap;
+  std::vector<RawLoadCommand> LoadCommands;
+};
+
+// Implementation for reading Mach-O header and load commands.
+// This is 32 or 64 bit arch specific.
+template <class T>
+class cmMachOHeaderAndLoadCommandsImpl : public cmMachOHeaderAndLoadCommands
+{
+public:
+  cmMachOHeaderAndLoadCommandsImpl(bool _swap)
+    : cmMachOHeaderAndLoadCommands(_swap)
+  {
+  }
+  bool read_mach_o(cmsys::ifstream& fin)
+  {
+    if (!read(fin, this->Header)) {
+      return false;
+    }
+    this->Header.cputype = swap(this->Header.cputype);
+    this->Header.cpusubtype = swap(this->Header.cpusubtype);
+    this->Header.filetype = swap(this->Header.filetype);
+    this->Header.ncmds = swap(this->Header.ncmds);
+    this->Header.sizeofcmds = swap(this->Header.sizeofcmds);
+    this->Header.flags = swap(this->Header.flags);
+
+    return read_load_commands(this->Header.ncmds, this->Header.sizeofcmds,
+                              fin);
+  }
+
+protected:
+  T Header;
+};
+
+bool cmMachOHeaderAndLoadCommands::read_load_commands(uint32_t ncmds,
+                                                      uint32_t sizeofcmds,
+                                                      cmsys::ifstream& fin)
+{
+  uint32_t size_read = 0;
+  this->LoadCommands.resize(ncmds);
+  for (uint32_t i = 0; i < ncmds; i++) {
+    load_command lc;
+    if (!peek(fin, lc)) {
+      return false;
+    }
+    lc.cmd = swap(lc.cmd);
+    lc.cmdsize = swap(lc.cmdsize);
+    size_read += lc.cmdsize;
+
+    RawLoadCommand& c = this->LoadCommands[i];
+    c.LoadCommand.resize(lc.cmdsize);
+    if (!read(fin, c.LoadCommand)) {
+      return false;
+    }
+  }
+
+  if (size_read != sizeofcmds) {
+    this->LoadCommands.clear();
+    return false;
+  }
+
+  return true;
+}
+
+class cmMachOInternal
+{
+public:
+  cmMachOInternal(const char* fname);
+  ~cmMachOInternal();
+
+  // read a Mach-O file
+  bool read_mach_o(uint32_t file_offset);
+
+  // the file we are reading
+  cmsys::ifstream Fin;
+
+  // The archs in the universal binary
+  // If the binary is not a universal binary, this will be empty.
+  std::vector<fat_arch> FatArchs;
+
+  // the error message while parsing
+  std::string ErrorMessage;
+
+  // the list of Mach-O's
+  std::vector<cmMachOHeaderAndLoadCommands*> MachOList;
+};
+
+cmMachOInternal::cmMachOInternal(const char* fname)
+  : Fin(fname)
+{
+  // Quit now if the file could not be opened.
+  if (!this->Fin || !this->Fin.get()) {
+    this->ErrorMessage = "Error opening input file.";
+    return;
+  }
+
+  if (!this->Fin.seekg(0)) {
+    this->ErrorMessage = "Error seeking to beginning of file.";
+    return;
+  }
+
+  // Read the binary identification block.
+  uint32_t magic = 0;
+  if (!peek(this->Fin, magic)) {
+    this->ErrorMessage = "Error reading Mach-O identification.";
+    return;
+  }
+
+  // Verify the binary identification.
+  if (!(magic == MH_CIGAM || magic == MH_MAGIC || magic == MH_CIGAM_64 ||
+        magic == MH_MAGIC_64 || magic == FAT_CIGAM || magic == FAT_MAGIC)) {
+    this->ErrorMessage = "File does not have a valid Mach-O identification.";
+    return;
+  }
+
+  if (magic == FAT_MAGIC || magic == FAT_CIGAM) {
+    // this is a universal binary
+    fat_header header;
+    if (!read(this->Fin, header)) {
+      this->ErrorMessage = "Error reading fat header.";
+      return;
+    }
+
+    // read fat_archs
+    this->FatArchs.resize(OSSwapBigToHostInt32(header.nfat_arch));
+    if (!read(this->Fin, this->FatArchs)) {
+      this->ErrorMessage = "Error reading fat header archs.";
+      return;
+    }
+
+    // parse each Mach-O file
+    for (size_t i = 0; i < this->FatArchs.size(); i++) {
+      const fat_arch& arch = this->FatArchs[i];
+      if (!this->read_mach_o(OSSwapBigToHostInt32(arch.offset))) {
+        return;
+      }
+    }
+  } else {
+    // parse Mach-O file at the beginning of the file
+    this->read_mach_o(0);
+  }
+}
+
+cmMachOInternal::~cmMachOInternal()
+{
+  for (size_t i = 0; i < this->MachOList.size(); i++) {
+    delete this->MachOList[i];
+  }
+}
+
+bool cmMachOInternal::read_mach_o(uint32_t file_offset)
+{
+  if (!this->Fin.seekg(file_offset)) {
+    this->ErrorMessage = "Failed to locate Mach-O content.";
+    return false;
+  }
+
+  uint32_t magic;
+  if (!peek(this->Fin, magic)) {
+    this->ErrorMessage = "Error reading Mach-O identification.";
+    return false;
+  }
+
+  cmMachOHeaderAndLoadCommands* f = NULL;
+  if (magic == MH_CIGAM || magic == MH_MAGIC) {
+    bool swap = false;
+    if (magic == MH_CIGAM) {
+      swap = true;
+    }
+    f = new cmMachOHeaderAndLoadCommandsImpl<mach_header>(swap);
+  } else if (magic == MH_CIGAM_64 || magic == MH_MAGIC_64) {
+    bool swap = false;
+    if (magic == MH_CIGAM_64) {
+      swap = true;
+    }
+    f = new cmMachOHeaderAndLoadCommandsImpl<mach_header_64>(swap);
+  }
+
+  if (f && f->read_mach_o(this->Fin)) {
+    this->MachOList.push_back(f);
+  } else {
+    delete f;
+    this->ErrorMessage = "Failed to read Mach-O header.";
+    return false;
+  }
+
+  return true;
+}
+
+//============================================================================
+// External class implementation.
+
+cmMachO::cmMachO(const char* fname)
+  : Internal(0)
+{
+  this->Internal = new cmMachOInternal(fname);
+}
+
+cmMachO::~cmMachO()
+{
+  delete this->Internal;
+}
+
+std::string const& cmMachO::GetErrorMessage() const
+{
+  return this->Internal->ErrorMessage;
+}
+
+bool cmMachO::Valid() const
+{
+  return !this->Internal->MachOList.empty();
+}
+
+bool cmMachO::GetInstallName(std::string& install_name)
+{
+  if (this->Internal->MachOList.empty()) {
+    return false;
+  }
+
+  // grab the first Mach-O and get the install name from that one
+  cmMachOHeaderAndLoadCommands* macho = this->Internal->MachOList[0];
+  for (size_t i = 0; i < macho->load_commands().size(); i++) {
+    const cmMachOHeaderAndLoadCommands::RawLoadCommand& cmd =
+      macho->load_commands()[i];
+    uint32_t lc_cmd = cmd.type(macho);
+    if (lc_cmd == LC_ID_DYLIB || lc_cmd == LC_LOAD_WEAK_DYLIB ||
+        lc_cmd == LC_LOAD_DYLIB) {
+      if (sizeof(dylib_command) < cmd.LoadCommand.size()) {
+        uint32_t namelen = cmd.LoadCommand.size() - sizeof(dylib_command);
+        install_name.assign(&cmd.LoadCommand[sizeof(dylib_command)], namelen);
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+void cmMachO::PrintInfo(std::ostream& /*os*/) const
+{
+}