glibc/malloc/Versions, branch master

Remove unused scratch_buffer_dupfree

2022-10-28T17:43:58Z

Turns out scratch_buffer_dupfree internal API was unused since commit ef0700004bf0dccf493a5e8e21f71d9e7972ea9f stdlib: Simplify buffer management in canonicalize And the related test in malloc/tst-scratch_buffer had issues so it's better to remove it completely. Reviewed-by: Florian Weimer

Move malloc_{g,s}et_state to libc_malloc_debug

2021-07-22T13:08:10Z

These deprecated functions are only safe to call from __malloc_initialize_hook and as a result, are not useful in the general case. Move the implementations to libc_malloc_debug so that existing binaries that need it will now have to preload the debug DSO to work correctly. This also allows simplification of the core malloc implementation by dropping all the undumping support code that was added to make malloc_set_state work. One known breakage is that of ancient emacs binaries that depend on this. They will now crash when running with this libc. With LD_BIND_NOW=1, it will terminate immediately because of not being able to find malloc_set_state but with lazy binding it will crash in unpredictable ways. It will need a preloaded libc_malloc_debug.so so that its initialization hook is executed to allow its malloc implementation to work properly. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell

glibc.malloc.check: Wean away from malloc hooks

2021-07-22T13:08:08Z

The malloc-check debugging feature is tightly integrated into glibc malloc, so thanks to an idea from Florian Weimer, much of the malloc implementation has been moved into libc_malloc_debug.so to support malloc-check. Due to this, glibc malloc and malloc-check can no longer work together; they use altogether different (but identical) structures for heap management. This should not make a difference though since the malloc check hook is not disabled anywhere. malloc_set_state does, but it does so early enough that it shouldn't cause any problems. The malloc check tunable is now in the debug DSO and has no effect when the DSO is not preloaded. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell

mtrace: Wean away from malloc hooks

2021-07-22T13:08:06Z

Wean mtrace away from the malloc hooks and move them into the debug DSO. Split the API away from the implementation so that we can add the API to libc.so as well as libc_malloc_debug.so, with the libc implementations being empty. Update localplt data since memalign no longer has any callers after this change. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell

mcheck: Wean away from malloc hooks [BZ #23489]

2021-07-22T13:08:02Z

Split the mcheck implementation into the debugging hooks and API so that the API can be replicated in libc and libc_malloc_debug.so. The libc APIs always result in failure. The mcheck implementation has also been moved entirely into libc_malloc_debug.so and with it, all of the hook initialization code can now be moved into the debug library. Now the initialization can be done independently of libc internals. With this patch, libc_malloc_debug.so can no longer be used with older libcs, which is not its goal anyway. tst-vfork3 breaks due to this since it spawns shell scripts, which in turn execute using the system glibc. Move the test to tests-container so that only the built glibc is used. This move also fixes bugs in the mcheck version of memalign and realloc, thus allowing removal of the tests from tests-mcheck exclusion list. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell

Move malloc hooks into a compat DSO

2021-07-22T13:07:59Z

Remove all malloc hook uses from core malloc functions and move it into a new library libc_malloc_debug.so. With this, the hooks now no longer have any effect on the core library. libc_malloc_debug.so is a malloc interposer that needs to be preloaded to get hooks functionality back so that the debugging features that depend on the hooks, i.e. malloc-check, mcheck and mtrace work again. Without the preloaded DSO these debugging features will be nops. These features will be ported away from hooks in subsequent patches. Similarly, legacy applications that need hooks functionality need to preload libc_malloc_debug.so. The symbols exported by libc_malloc_debug.so are maintained at exactly the same version as libc.so. Finally, static binaries will no longer be able to use malloc debugging features since they cannot preload the debugging DSO. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell

Move mcheck symbol from stdlib to malloc

2021-07-08T13:17:21Z

It is defined in malloc, so it belongs there. Verified on x86_64 that the built libraries are identical despite this change.

malloc: Drop __malloc_initialized from Versions

2021-06-22T14:44:31Z

__malloc_initialized is mentioned in Versions when it is actually an internal symbol. The resultant binaries are identical.

malloc: Add scratch_buffer_dupfree

2021-01-05T14:33:16Z

It returns a copy of the buffer up to a defined size. It will be used on realpath sync with gnulib.

Update mallinfo2 ABI, and test

2020-09-17T22:49:30Z

This patch adds the ABI-related bits to reflect the new mallinfo2 function, and adds a test case to verify basic functionality. Reviewed-by: Adhemerval Zanella