[haiku-bugs] Re: [Haiku] #8520: runtime loader should check elf headers for things like architecture.
- From: "bonefish" <trac@xxxxxxxxxxxx>
- Date: Fri, 04 May 2012 21:11:53 -0000
#8520: runtime loader should check elf headers for things like architecture.
-------------------------------------+----------------------------
Reporter: kallisti5 | Owner: bonefish
Type: enhancement | Status: new
Priority: normal | Milestone: R1/alpha4
Component: System/runtime_loader | Version: R1/Development
Resolution: | Keywords:
Blocked By: | Blocking:
Has a Patch: 1 | Platform: All
-------------------------------------+----------------------------
Comment (by bonefish):
@kallisti5: The check should not only be done in `test_executable()`. That
function is called for an executable that is asked to be executed. It is
not called for libraries or add-ons being loaded. So a check in
`parse_elf_header()` is required as well.
Regarding the patch:
- The new error macro definitions should be appended to the block for the
runtime loader errors, continuing the sequence.
- I don't see what error condition `B_BAD_IMAGE_PLATFORM` would indicate.
- For `B_BAD_IMAGE_ARCHITECTURE` I would find "MISMATCHING" instead of
"BAD" more fitting. I'd also drop the "IMAGE".
- I doubt `test_architecture()` even compiles. It declares `char
name[128]`, but assigns string literals to the variable.
- I would organize the architecture check differently: In some header
define a macro `ELF_MACHINE` for the expected ELF machine via #ifdef
chain. The check in `test_architecture()` becomes `elfMachine ==
ELF_MACHINE`. The debug output is not needed IMO, so `test_architecture()`
becomes superfluous; the check can be inlined in both `test_executable()`
and `parse_elf_header()`.
Regarding your TODO question: No, the i386/x86_64 check cannot be done in
the runtime loader. The kernel already needs to load the respective
runtime loader matching the architecture.
@X512: No, it isn't that simple. At some points (whether it is shared
object boundaries or the kernel interface and client-server protocols) the
emulated program needs to interface with the native system. At these
points a translation has to happen that qemu cannot possibly know about.
E.g. a C structure that is passed to the kernel doesn't necessarily have
the same layout for all architectures (certain datatypes may or may not
change width depending on the architecture). The information for such a
conversion is not present in the object code.
--
Ticket URL: <http://dev.haiku-os.org/ticket/8520#comment:11>
Haiku <http://dev.haiku-os.org>
Haiku - the operating system.
Other related posts: