Date: Tue, 6 May 2014 18:07:59 +0000 (UTC) From: Mark Johnston <markj@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r265456 - head/libexec/rtld-elf Message-ID: <201405061807.s46I7xxt048377@svn.freebsd.org>
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Author: markj Date: Tue May 6 18:07:58 2014 New Revision: 265456 URL: http://svnweb.freebsd.org/changeset/base/265456 Log: Add a postinit debugger hook to rtld. This will be used by dtrace(1) to halt the victim process before its entry point is called, at which point probes and DOF data are registered with the kernel. The r_debug_state hook cannot be used for this purpose, as it is called before the program's init routines are invoked and in particular before DOF data is registered (via drti.o). Reviewed by: kib MFC after: 2 weeks Modified: head/libexec/rtld-elf/Symbol.map head/libexec/rtld-elf/rtld.c Modified: head/libexec/rtld-elf/Symbol.map ============================================================================== --- head/libexec/rtld-elf/Symbol.map Tue May 6 16:51:07 2014 (r265455) +++ head/libexec/rtld-elf/Symbol.map Tue May 6 18:07:58 2014 (r265456) @@ -30,4 +30,5 @@ FBSDprivate_1.0 { _rtld_atfork_post; _rtld_addr_phdr; _rtld_get_stack_prot; + _rtld_debug_postinit; }; Modified: head/libexec/rtld-elf/rtld.c ============================================================================== --- head/libexec/rtld-elf/rtld.c Tue May 6 16:51:07 2014 (r265455) +++ head/libexec/rtld-elf/rtld.c Tue May 6 18:07:58 2014 (r265456) @@ -162,6 +162,7 @@ static bool matched_symbol(SymLook *, co const unsigned long); void r_debug_state(struct r_debug *, struct link_map *) __noinline; +void _r_debug_postinit(struct link_map *) __noinline; /* * Data declarations. @@ -637,6 +638,7 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_ if (obj_main->crt_no_init) preinit_main(); objlist_call_init(&initlist, &lockstate); + _r_debug_postinit(&obj_main->linkmap); objlist_clear(&initlist); dbg("loading filtees"); for (obj = obj_list->next; obj != NULL; obj = obj->next) { @@ -3553,6 +3555,19 @@ r_debug_state(struct r_debug* rd, struct } /* + * A function called after init routines have completed. This can be used to + * break before a program's entry routine is called, and can be used when + * main is not available in the symbol table. + */ +void +_r_debug_postinit(struct link_map *m) +{ + + /* See r_debug_state(). */ + __asm __volatile("" : : : "memory"); +} + +/* * Get address of the pointer variable in the main program. * Prefer non-weak symbol over the weak one. */
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