Allow to retrieve id of a module from memory instead of going to disk for iOS.

 Allow macho_id and macho_walker to read data from memory.
 Wire up this when reading module on iOS.
Review URL: http://breakpad.appspot.com/319001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@873 4c0a9323-5329-0410-9bdc-e9ce6186880e

4 files changed, 77 insertions, 24 deletions

diff --git a/src/common/mac/macho_id.cc b/src/common/mac/macho_id.cc
index 44e78205..ce0ecff3 100644
--- a/src/common/mac/macho_id.cc
+++ b/src/common/mac/macho_id.cc
@@ -52,17 +52,24 @@ extern "C" {  // necessary for Leopard
 namespace MacFileUtilities {
 
 MachoID::MachoID(const char *path)
-   : file_(0), 
+   : memory_(0),
+     memory_size_(0),
+     crc_(0), 
+     md5_context_(), 
+     update_function_(NULL) {
+  strlcpy(path_, path, sizeof(path_));
+}
+
+MachoID::MachoID(const char *path, void *memory, size_t size)
+   : memory_(memory),
+     memory_size_(size),
      crc_(0), 
      md5_context_(), 
      update_function_(NULL) {
   strlcpy(path_, path, sizeof(path_));
-  file_ = open(path, O_RDONLY);
 }
 
 MachoID::~MachoID() {
-  if (file_ != -1)
-    close(file_);
 }
 
 // The CRC info is from http://en.wikipedia.org/wiki/Adler-32
@@ -144,10 +151,8 @@ void MachoID::Update(MachoWalker *walker, off_t offset, size_t size) {
 
 bool MachoID::UUIDCommand(int cpu_type, unsigned char bytes[16]) {
   struct breakpad_uuid_command uuid_cmd;
-  MachoWalker walker(path_, UUIDWalkerCB, &uuid_cmd);
-
   uuid_cmd.cmd = 0;
-  if (!walker.WalkHeader(cpu_type))
+  if (!WalkHeader(cpu_type, UUIDWalkerCB, &uuid_cmd))
     return false;
 
   // If we found the command, we'll have initialized the uuid_command
@@ -162,10 +167,8 @@ bool MachoID::UUIDCommand(int cpu_type, unsigned char bytes[16]) {
 
 bool MachoID::IDCommand(int cpu_type, unsigned char identifier[16]) {
   struct dylib_command dylib_cmd;
-  MachoWalker walker(path_, IDWalkerCB, &dylib_cmd);
-
   dylib_cmd.cmd = 0;
-  if (!walker.WalkHeader(cpu_type))
+  if (!WalkHeader(cpu_type, IDWalkerCB, &dylib_cmd))
     return false;
 
   // If we found the command, we'll have initialized the dylib_command
@@ -204,29 +207,39 @@ bool MachoID::IDCommand(int cpu_type, unsigned char identifier[16]) {
 }
 
 uint32_t MachoID::Adler32(int cpu_type) {
-  MachoWalker walker(path_, WalkerCB, this);
   update_function_ = &MachoID::UpdateCRC;
   crc_ = 0;
 
-  if (!walker.WalkHeader(cpu_type))
+  if (!WalkHeader(cpu_type, WalkerCB, this))
     return 0;
 
   return crc_;
 }
 
 bool MachoID::MD5(int cpu_type, unsigned char identifier[16]) {
-  MachoWalker walker(path_, WalkerCB, this);
   update_function_ = &MachoID::UpdateMD5;
 
   MD5Init(&md5_context_);
 
-  if (!walker.WalkHeader(cpu_type))
+  if (!WalkHeader(cpu_type, WalkerCB, this))
     return false;
 
   MD5Final(identifier, &md5_context_);
   return true;
 }
 
+bool MachoID::WalkHeader(int cpu_type,
+                         MachoWalker::LoadCommandCallback callback,
+                         void *context) {
+  if (memory_) {
+    MachoWalker walker(memory_, memory_size_, callback, context);
+    return walker.WalkHeader(cpu_type);
+  } else {
+    MachoWalker walker(path_, callback, context);
+    return walker.WalkHeader(cpu_type);
+  }
+}
+
 // static
 bool MachoID::WalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
                        bool swap, void *context) {
diff --git a/src/common/mac/macho_id.h b/src/common/mac/macho_id.h
index 9bcefc56..a5338120 100644
--- a/src/common/mac/macho_id.h
+++ b/src/common/mac/macho_id.h
@@ -37,15 +37,15 @@
 #include <limits.h>
 #include <mach-o/loader.h>
 
+#include "common/mac/macho_walker.h"
 #include "common/md5.h"
 
 namespace MacFileUtilities {
 
-class MachoWalker;
-
 class MachoID {
  public:
   MachoID(const char *path);
+  MachoID(const char *path, void *memory, size_t size);
   ~MachoID();
 
   // For the given |cpu_type|, return a UUID from the LC_UUID command.
@@ -80,6 +80,10 @@ class MachoID {
   // Bottleneck for update routines
   void Update(MachoWalker *walker, off_t offset, size_t size);
 
+  // Factory for the MachoWalker
+  bool WalkHeader(int cpu_type, MachoWalker::LoadCommandCallback callback,
+                  void *context);
+
   // The callback from the MachoWalker for CRC and MD5
   static bool WalkerCB(MachoWalker *walker, load_command *cmd, off_t offset,
                        bool swap, void *context);
@@ -95,8 +99,11 @@ class MachoID {
   // File path
   char path_[PATH_MAX];
 
-  // File descriptor
-  int file_;
+  // Memory region to read from
+  void *memory_;
+
+  // Size of the memory region
+  size_t memory_size_;
 
   // The current crc value
   uint32_t crc_;
diff --git a/src/common/mac/macho_walker.cc b/src/common/mac/macho_walker.cc
index 3e8fe211..00fde03e 100644
--- a/src/common/mac/macho_walker.cc
+++ b/src/common/mac/macho_walker.cc
@@ -52,6 +52,8 @@ namespace MacFileUtilities {
 MachoWalker::MachoWalker(const char *path, LoadCommandCallback callback,
                          void *context)
     : file_(0),
+      memory_(NULL),
+      memory_size_(0),
       callback_(callback),
       callback_context_(context),
       current_header_(NULL),
@@ -60,6 +62,18 @@ MachoWalker::MachoWalker(const char *path, LoadCommandCallback callback,
   file_ = open(path, O_RDONLY);
 }
 
+MachoWalker::MachoWalker(void *memory, size_t size,
+                         LoadCommandCallback callback, void *context)
+    : file_(0),
+      memory_(memory),
+      memory_size_(size),
+      callback_(callback),
+      callback_context_(context),
+      current_header_(NULL),
+      current_header_size_(0),
+      current_header_offset_(0) {
+}
+
 MachoWalker::~MachoWalker() {
   if (file_ != -1)
     close(file_);
@@ -90,7 +104,19 @@ bool MachoWalker::WalkHeader(int cpu_type) {
 }
 
 bool MachoWalker::ReadBytes(void *buffer, size_t size, off_t offset) {
-  return pread(file_, buffer, size, offset) == (ssize_t)size;
+  if (memory_) {
+    bool result = true;
+    if (offset + size > memory_size_) {
+      size = memory_size_ - offset;
+      result = false;
+    }
+    if (size < 0)
+      return false;
+    memcpy(buffer, static_cast<char *>(memory_) + offset, size);
+    return result;
+  } else {
+    return pread(file_, buffer, size, offset) == (ssize_t)size;
+  }
 }
 
 bool MachoWalker::CurrentHeader(struct mach_header_64 *header, off_t *offset) {
diff --git a/src/common/mac/macho_walker.h b/src/common/mac/macho_walker.h
index 0d30b5c0..cee3eb8d 100644
--- a/src/common/mac/macho_walker.h
+++ b/src/common/mac/macho_walker.h
@@ -52,7 +52,8 @@ class MachoWalker {
                                       off_t offset, bool swap, void *context);
 
   MachoWalker(const char *path, LoadCommandCallback callback, void *context);
-  MachoWalker(int file_descriptor, LoadCommandCallback callback, void *context);
+  MachoWalker(void *memory, size_t size, LoadCommandCallback callback,
+              void *context);
   ~MachoWalker();
 
   // Begin walking the header for |cpu_type|.  If |cpu_type| is 0, then the
@@ -68,7 +69,7 @@ class MachoWalker {
 
   // Read |size| bytes from the opened file at |offset| into |buffer|
   bool ReadBytes(void *buffer, size_t size, off_t offset);
-  
+
   // Return the current header and header offset
   bool CurrentHeader(struct mach_header_64 *header, off_t *offset);
 
@@ -87,19 +88,25 @@ class MachoWalker {
   // File descriptor to the opened file
   int file_;
 
+  // Memory location to read from.
+  void *memory_;
+
+  // Size of the memory segment we can read from.
+  size_t memory_size_;
+
   // User specified callback & context
   LoadCommandCallback callback_;
   void *callback_context_;
-  
+
   // Current header, size, and offset.  The mach_header_64 is used for both
   // 32-bit and 64-bit headers because they only differ in their last field
-  // (reserved).  By adding the |current_header_size_| and the 
+  // (reserved).  By adding the |current_header_size_| and the
   // |current_header_offset_|, you can determine the offset in the file just
   // after the header.
   struct mach_header_64 *current_header_;
   unsigned long current_header_size_;
   off_t current_header_offset_;
-  
+
  private:
   MachoWalker(const MachoWalker &);
   MachoWalker &operator=(const MachoWalker &);