diff options
Diffstat (limited to 'elf/rtld.c')
| -rw-r--r-- | elf/rtld.c | 100 |
1 files changed, 65 insertions, 35 deletions
@@ -371,7 +371,6 @@ struct rtld_global_ro _rtld_global_ro attribute_relro = ._dl_error_free = _dl_error_free, ._dl_tls_get_addr_soft = _dl_tls_get_addr_soft, ._dl_libc_freeres = __rtld_libc_freeres, - ._dl_readonly_area = _dl_readonly_area, }; /* If we would use strong_alias here the compiler would see a non-hidden definition. This would undo the effect of the previous @@ -428,7 +427,6 @@ static ElfW(Addr) _dl_start_final (void *arg, /* These are defined magically by the linker. */ extern const ElfW(Ehdr) __ehdr_start attribute_hidden; -extern char _etext[] attribute_hidden; extern char _end[] attribute_hidden; @@ -459,6 +457,7 @@ _dl_start_final (void *arg, struct dl_start_final_info *info) /* Do not use an initializer for these members because it would interfere with __rtld_static_init. */ GLRO (dl_find_object) = &_dl_find_object; + GLRO (dl_readonly_area) = &_dl_readonly_area; /* If it hasn't happen yet record the startup time. */ rtld_timer_start (&start_time); @@ -477,8 +476,10 @@ _dl_start_final (void *arg, struct dl_start_final_info *info) #endif _dl_setup_hash (&_dl_rtld_map); _dl_rtld_map.l_real = &_dl_rtld_map; - _dl_rtld_map.l_map_start = (ElfW(Addr)) &__ehdr_start; - _dl_rtld_map.l_map_end = (ElfW(Addr)) _end; + _dl_rtld_map.l_map_start + = (ElfW(Addr)) DL_ADDRESS_WITHOUT_RELOC (&__ehdr_start); + _dl_rtld_map.l_map_end + = (ElfW(Addr)) DL_ADDRESS_WITHOUT_RELOC (_end); /* Copy the TLS related data if necessary. */ #ifndef DONT_USE_BOOTSTRAP_MAP # if NO_TLS_OFFSET != 0 @@ -1238,6 +1239,60 @@ rtld_setup_main_map (struct link_map *main_map) return has_interp; } +/* Set up the program header information for the dynamic linker + itself. It can be accessed via _r_debug and dl_iterate_phdr + callbacks, and it is used by _dl_find_object. */ +static void +rtld_setup_phdr (void) +{ + /* Starting from binutils-2.23, the linker will define the magic + symbol __ehdr_start to point to our own ELF header if it is + visible in a segment that also includes the phdrs. */ + + const ElfW(Ehdr) *rtld_ehdr = &__ehdr_start; + assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr); + assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr))); + + const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff; + + _dl_rtld_map.l_phdr = rtld_phdr; + _dl_rtld_map.l_phnum = rtld_ehdr->e_phnum; + + + _dl_rtld_map.l_contiguous = 1; + /* The linker may not have produced a contiguous object. The kernel + will load the object with actual gaps (unlike the glibc loader + for shared objects, which always produces a contiguous mapping). + See similar logic in rtld_setup_main_map above. */ + { + ElfW(Addr) expected_load_address = 0; + for (const ElfW(Phdr) *ph = rtld_phdr; ph < &rtld_phdr[rtld_ehdr->e_phnum]; + ++ph) + if (ph->p_type == PT_LOAD) + { + ElfW(Addr) mapstart = ph->p_vaddr & ~(GLRO(dl_pagesize) - 1); + if (_dl_rtld_map.l_contiguous && expected_load_address != 0 + && expected_load_address != mapstart) + _dl_rtld_map.l_contiguous = 0; + ElfW(Addr) allocend = ph->p_vaddr + ph->p_memsz; + /* The next expected address is the page following this load + segment. */ + expected_load_address = ((allocend + GLRO(dl_pagesize) - 1) + & ~(GLRO(dl_pagesize) - 1)); + } + } + + /* PT_GNU_RELRO is usually the last phdr. */ + size_t cnt = rtld_ehdr->e_phnum; + while (cnt-- > 0) + if (rtld_phdr[cnt].p_type == PT_GNU_RELRO) + { + _dl_rtld_map.l_relro_addr = rtld_phdr[cnt].p_vaddr; + _dl_rtld_map.l_relro_size = rtld_phdr[cnt].p_memsz; + break; + } +} + /* Adjusts the contents of the stack and related globals for the user entry point. The ld.so processed skip_args arguments and bumped _dl_argv and _dl_argc accordingly. Those arguments are removed from @@ -1704,33 +1759,7 @@ dl_main (const ElfW(Phdr) *phdr, ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded; ++GL(dl_load_adds); - /* Starting from binutils-2.23, the linker will define the magic symbol - __ehdr_start to point to our own ELF header if it is visible in a - segment that also includes the phdrs. If that's not available, we use - the old method that assumes the beginning of the file is part of the - lowest-addressed PT_LOAD segment. */ - - /* Set up the program header information for the dynamic linker - itself. It is needed in the dl_iterate_phdr callbacks. */ - const ElfW(Ehdr) *rtld_ehdr = &__ehdr_start; - assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr); - assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr))); - - const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff; - - _dl_rtld_map.l_phdr = rtld_phdr; - _dl_rtld_map.l_phnum = rtld_ehdr->e_phnum; - - - /* PT_GNU_RELRO is usually the last phdr. */ - size_t cnt = rtld_ehdr->e_phnum; - while (cnt-- > 0) - if (rtld_phdr[cnt].p_type == PT_GNU_RELRO) - { - _dl_rtld_map.l_relro_addr = rtld_phdr[cnt].p_vaddr; - _dl_rtld_map.l_relro_size = rtld_phdr[cnt].p_memsz; - break; - } + rtld_setup_phdr (); /* Add the dynamic linker to the TLS list if it also uses TLS. */ if (_dl_rtld_map.l_tls_blocksize != 0) @@ -1777,8 +1806,7 @@ dl_main (const ElfW(Phdr) *phdr, elf_setup_debug_entry (main_map, r); /* We start adding objects. */ - r->r_state = RT_ADD; - _dl_debug_state (); + _dl_debug_change_state (r, RT_ADD); LIBC_PROBE (init_start, 2, LM_ID_BASE, r); /* Auditing checkpoint: we are ready to signal that the initial map @@ -2313,6 +2341,9 @@ dl_main (const ElfW(Phdr) *phdr, __rtld_mutex_init (); __rtld_malloc_init_real (main_map); + + /* Update copy-relocated _r_debug if necessary. */ + _dl_debug_post_relocate (main_map); } /* All ld.so initialization is complete. Apply RELRO. */ @@ -2333,8 +2364,7 @@ dl_main (const ElfW(Phdr) *phdr, /* Notify the debugger all new objects are now ready to go. We must re-get the address since by now the variable might be in another object. */ r = _dl_debug_update (LM_ID_BASE); - r->r_state = RT_CONSISTENT; - _dl_debug_state (); + _dl_debug_change_state (r, RT_CONSISTENT); LIBC_PROBE (init_complete, 2, LM_ID_BASE, r); /* Auditing checkpoint: we have added all objects. */ |