From 2d2d9f2b48a943fa556301db532103d09800da4d Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Thu, 22 Jul 2021 18:37:59 +0530 Subject: Move malloc hooks into a compat DSO 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 --- resolv/Makefile | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'resolv') diff --git a/resolv/Makefile b/resolv/Makefile index e138a1fdac..59e599535c 100644 --- a/resolv/Makefile +++ b/resolv/Makefile @@ -215,19 +215,22 @@ $(objpfx)tst-res_hconf_reorder: $(shared-thread-library) tst-res_hconf_reorder-ENV = RESOLV_REORDER=on $(objpfx)tst-leaks: $(objpfx)libresolv.so -tst-leaks-ENV = MALLOC_TRACE=$(objpfx)tst-leaks.mtrace +tst-leaks-ENV = MALLOC_TRACE=$(objpfx)tst-leaks.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so $(objpfx)mtrace-tst-leaks.out: $(objpfx)tst-leaks.out $(common-objpfx)malloc/mtrace $(objpfx)tst-leaks.mtrace > $@; \ $(evaluate-test) -tst-leaks2-ENV = MALLOC_TRACE=$(objpfx)tst-leaks2.mtrace +tst-leaks2-ENV = MALLOC_TRACE=$(objpfx)tst-leaks2.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so $(objpfx)mtrace-tst-leaks2.out: $(objpfx)tst-leaks2.out { test -r $(objpfx)tst-leaks2.mtrace \ || ( echo "tst-leaks2.mtrace does not exist"; exit 77; ) \ && $(common-objpfx)malloc/mtrace $(objpfx)tst-leaks2.mtrace; } > $@; \ $(evaluate-test) -tst-resolv-res_ninit-ENV = MALLOC_TRACE=$(objpfx)tst-resolv-res_ninit.mtrace +tst-resolv-res_ninit-ENV = MALLOC_TRACE=$(objpfx)tst-resolv-res_ninit.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so $(objpfx)mtrace-tst-resolv-res_ninit.out: $(objpfx)tst-resolv-res_ninit.out $(common-objpfx)malloc/mtrace \ $(objpfx)tst-resolv-res_ninit.mtrace > $@; \ -- cgit 1.4.1