Some plumbing for the beginning of getting handles into snapshot/minidump

compat/non_win/dbghelp.h

Index: compat/non_win/dbghelp.h
diff --git a/compat/non_win/dbghelp.h b/compat/non_win/dbghelp.h
index 6fed86bdaaeb5b77674a2c0375d71df2f02fca46..cd5fa1ba71c8fd735e49b2e8ff089862ae7b9c72 100644
--- a/compat/non_win/dbghelp.h
+++ b/compat/non_win/dbghelp.h
@@ -621,6 +621,75 @@ struct __attribute__((packed, aligned(4))) MINIDUMP_MEMORY_LIST {
   MINIDUMP_MEMORY_DESCRIPTOR MemoryRanges[0];
 };
 
+//! \brief Contains the state of an individual system handle at the time the
+//!     snapshot was taken.
+//!
+//! \sa MINIDUMP_HANDLE_DESCRIPTOR_2
+struct __attribute__((packed, aligned(4))) MINIDUMP_HANDLE_DESCRIPTOR {
+  //! \brief The operating system handle value.
+  uint64_t Handle;
+
+  //! \brief An RVA to a MINIDUMP_STRING structure that specifies the object
+  //!     type of the handle. This member can be zero.
+  RVA TypeNameRva;
+
+  //! \brief An RVA to a MINIDUMP_STRING structure that specifies the object
+  //!     name of the handle. This member can be zero.
+  RVA ObjectNameRva;
+
+  //! \brief The meaning of this member depends on the handle type and the
+  //!     operating system. On Windows, this corresponds to `OBJ_INHERIT`,

[Mark Mentovai, 2015/10/14 23:55:13]

You got this documentation verbatim from Microsoft, but the meaning of
“operating system” to them is entirely different than its meaning in Crashpad,
which runs on non-Microsoft operating systems.

Your “on Windows” addition is then a little weird, because HANDLEs aren’t a
thing on non-Windows at all, and we wouldn’t see a MINIDUMP_HANDLE_DESCRIPTOR. I
think that Microsoft meant what we’d call the OS version.

Same for the remainder of the fields in this structure.

[scottmg, 2015/10/16 20:51:01]

Done.

+  //!     `OBJ_CASE_INSENSITIVE`, etc.
+  uint32_t Attributes;
+
+  //! \brief The meaning of this member depends on the handle type and the
+  //!     operating system. On Windows, this is the value of an `ACCESS_MASK`.
+  uint32_t GrantedAccess;
+
+  //! \brief The meaning of this member depends on the handle type and the
+  //!     operating system. On Windows, this is the number of open handles to
+  //!     the object that this handle refers to.
+  uint32_t HandleCount;
+
+  //! \brief The meaning of this member depends on the handle type and the
+  //!     operating system. On Windows, this is the number kernel references
+  //!     to the object that this handle refers to.
+  uint32_t PointerCount;
+};
+
+//! \brief Contains the state of an individual system handle at the time the
+//!     snapshot was taken.
+//!
+//! \sa MINIDUMP_HANDLE_DESCRIPTOR
+struct __attribute__((packed, aligned(4))) MINIDUMP_HANDLE_DESCRIPTOR_2
+    : public MINIDUMP_HANDLE_DESCRIPTOR {
+  //! \brief An RVA to a MINIDUMP_HANDLE_OBJECT_INFORMATION structure that
+  //!     specifies object-specific information. This member can be zero if
+  //!     there is no extra information.
+  RVA ObjectInfoRva;
+
+  //! \brief Must be zero.
+  uint32_t Reserved0;
+};
+
+//! \brief Represents the header for a handle data stream.
+struct __attribute((packed, aligned(4))) MINIDUMP_HANDLE_DATA_STREAM {
+  //! \brief The size of the header information for the stream, in bytes. This
+  //!     value is `sizeof(MINIDUMP_HANDLE_DATA_STREAM)`.
+  uint32_t SizeOfHeader;
+
+  //! \brief The size of a descriptor in the stream, in bytes. This value is
+  //!     `sizeof(MINIDUMP_HANDLE_DESCRIPTOR)` or
+  //!     `sizeof(MINIDUMP_HANDLE_DESCRIPTOR_2)`.
+  uint32_t SizeOfDescriptor;
+
+  //! \brief The number of descriptors in the stream.
+  uint32_t NumberOfDescriptors;
+
+  //! \brief Must be zero.
+  uint32_t Reserved;
+};
+
 //! \anchor MINIDUMP_MISCx
 //! \name MINIDUMP_MISC*
 //!