diff options
| -rw-r--r-- | elf/rtld.c | 303 |
1 files changed, 159 insertions, 144 deletions
diff --git a/elf/rtld.c b/elf/rtld.c index 39cab66e6b..4e0581e2c6 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1129,17 +1129,172 @@ rtld_chain_load (struct link_map *main_map, char *argv0) rtld_soname, pathname, errcode); } +/* Called to complete the initialization of the link map for the main + executable. Returns true if there is a PT_INTERP segment. */ +static bool +rtld_setup_main_map (struct link_map *main_map) +{ + /* This have already been filled in right after _dl_new_object, or + as part of _dl_map_object. */ + const ElfW(Phdr) *phdr = main_map->l_phdr; + ElfW(Word) phnum = main_map->l_phnum; + + bool has_interp = false; + + main_map->l_map_end = 0; + main_map->l_text_end = 0; + /* Perhaps the executable has no PT_LOAD header entries at all. */ + main_map->l_map_start = ~0; + /* And it was opened directly. */ + ++main_map->l_direct_opencount; + + /* Scan the program header table for the dynamic section. */ + for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph) + switch (ph->p_type) + { + case PT_PHDR: + /* Find out the load address. */ + main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr; + break; + case PT_DYNAMIC: + /* This tells us where to find the dynamic section, + which tells us everything we need to do. */ + main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr; + main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; + break; + case PT_INTERP: + /* This "interpreter segment" was used by the program loader to + find the program interpreter, which is this program itself, the + dynamic linker. We note what name finds us, so that a future + dlopen call or DT_NEEDED entry, for something that wants to link + against the dynamic linker as a shared library, will know that + the shared object is already loaded. */ + _dl_rtld_libname.name = ((const char *) main_map->l_addr + + ph->p_vaddr); + /* _dl_rtld_libname.next = NULL; Already zero. */ + GL(dl_rtld_map).l_libname = &_dl_rtld_libname; + + /* Ordinarilly, we would get additional names for the loader from + our DT_SONAME. This can't happen if we were actually linked as + a static executable (detect this case when we have no DYNAMIC). + If so, assume the filename component of the interpreter path to + be our SONAME, and add it to our name list. */ + if (GL(dl_rtld_map).l_ld == NULL) + { + const char *p = NULL; + const char *cp = _dl_rtld_libname.name; + + /* Find the filename part of the path. */ + while (*cp != '\0') + if (*cp++ == '/') + p = cp; + + if (p != NULL) + { + _dl_rtld_libname2.name = p; + /* _dl_rtld_libname2.next = NULL; Already zero. */ + _dl_rtld_libname.next = &_dl_rtld_libname2; + } + } + + has_interp = true; + break; + case PT_LOAD: + { + ElfW(Addr) mapstart; + ElfW(Addr) allocend; + + /* Remember where the main program starts in memory. */ + mapstart = (main_map->l_addr + + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1))); + if (main_map->l_map_start > mapstart) + main_map->l_map_start = mapstart; + + /* Also where it ends. */ + allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz; + if (main_map->l_map_end < allocend) + main_map->l_map_end = allocend; + if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end) + main_map->l_text_end = allocend; + } + break; + + case PT_TLS: + if (ph->p_memsz > 0) + { + /* Note that in the case the dynamic linker we duplicate work + here since we read the PT_TLS entry already in + _dl_start_final. But the result is repeatable so do not + check for this special but unimportant case. */ + main_map->l_tls_blocksize = ph->p_memsz; + main_map->l_tls_align = ph->p_align; + if (ph->p_align == 0) + main_map->l_tls_firstbyte_offset = 0; + else + main_map->l_tls_firstbyte_offset = (ph->p_vaddr + & (ph->p_align - 1)); + main_map->l_tls_initimage_size = ph->p_filesz; + main_map->l_tls_initimage = (void *) ph->p_vaddr; + + /* This image gets the ID one. */ + GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1; + } + break; + + case PT_GNU_STACK: + GL(dl_stack_flags) = ph->p_flags; + break; + + case PT_GNU_RELRO: + main_map->l_relro_addr = ph->p_vaddr; + main_map->l_relro_size = ph->p_memsz; + break; + } + /* Process program headers again, but scan them backwards so + that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */ + for (const ElfW(Phdr) *ph = &phdr[phnum]; ph != phdr; --ph) + switch (ph[-1].p_type) + { + case PT_NOTE: + _dl_process_pt_note (main_map, -1, &ph[-1]); + break; + case PT_GNU_PROPERTY: + _dl_process_pt_gnu_property (main_map, -1, &ph[-1]); + break; + } + + /* Adjust the address of the TLS initialization image in case + the executable is actually an ET_DYN object. */ + if (main_map->l_tls_initimage != NULL) + main_map->l_tls_initimage + = (char *) main_map->l_tls_initimage + main_map->l_addr; + if (! main_map->l_map_end) + main_map->l_map_end = ~0; + if (! main_map->l_text_end) + main_map->l_text_end = ~0; + if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name) + { + /* We were invoked directly, so the program might not have a + PT_INTERP. */ + _dl_rtld_libname.name = GL(dl_rtld_map).l_name; + /* _dl_rtld_libname.next = NULL; Already zero. */ + GL(dl_rtld_map).l_libname = &_dl_rtld_libname; + } + else + assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */ + + return has_interp; +} + static void dl_main (const ElfW(Phdr) *phdr, ElfW(Word) phnum, ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv) { - const ElfW(Phdr) *ph; struct link_map *main_map; size_t file_size; char *file; - bool has_interp = false; unsigned int i; bool prelinked = false; bool rtld_is_main = false; @@ -1353,7 +1508,7 @@ dl_main (const ElfW(Phdr) *phdr, load the program below unless it has a PT_GNU_STACK indicating nonexecutable stack is ok. */ - for (ph = phdr; ph < &phdr[phnum]; ++ph) + for (const ElfW(Phdr) *ph = phdr; ph < &phdr[phnum]; ++ph) if (ph->p_type == PT_GNU_STACK) { GL(dl_stack_flags) = ph->p_flags; @@ -1472,147 +1627,7 @@ dl_main (const ElfW(Phdr) *phdr, information for the program. */ } - main_map->l_map_end = 0; - main_map->l_text_end = 0; - /* Perhaps the executable has no PT_LOAD header entries at all. */ - main_map->l_map_start = ~0; - /* And it was opened directly. */ - ++main_map->l_direct_opencount; - - /* Scan the program header table for the dynamic section. */ - for (ph = phdr; ph < &phdr[phnum]; ++ph) - switch (ph->p_type) - { - case PT_PHDR: - /* Find out the load address. */ - main_map->l_addr = (ElfW(Addr)) phdr - ph->p_vaddr; - break; - case PT_DYNAMIC: - /* This tells us where to find the dynamic section, - which tells us everything we need to do. */ - main_map->l_ld = (void *) main_map->l_addr + ph->p_vaddr; - main_map->l_ld_readonly = (ph->p_flags & PF_W) == 0; - break; - case PT_INTERP: - /* This "interpreter segment" was used by the program loader to - find the program interpreter, which is this program itself, the - dynamic linker. We note what name finds us, so that a future - dlopen call or DT_NEEDED entry, for something that wants to link - against the dynamic linker as a shared library, will know that - the shared object is already loaded. */ - _dl_rtld_libname.name = ((const char *) main_map->l_addr - + ph->p_vaddr); - /* _dl_rtld_libname.next = NULL; Already zero. */ - GL(dl_rtld_map).l_libname = &_dl_rtld_libname; - - /* Ordinarilly, we would get additional names for the loader from - our DT_SONAME. This can't happen if we were actually linked as - a static executable (detect this case when we have no DYNAMIC). - If so, assume the filename component of the interpreter path to - be our SONAME, and add it to our name list. */ - if (GL(dl_rtld_map).l_ld == NULL) - { - const char *p = NULL; - const char *cp = _dl_rtld_libname.name; - - /* Find the filename part of the path. */ - while (*cp != '\0') - if (*cp++ == '/') - p = cp; - - if (p != NULL) - { - _dl_rtld_libname2.name = p; - /* _dl_rtld_libname2.next = NULL; Already zero. */ - _dl_rtld_libname.next = &_dl_rtld_libname2; - } - } - - has_interp = true; - break; - case PT_LOAD: - { - ElfW(Addr) mapstart; - ElfW(Addr) allocend; - - /* Remember where the main program starts in memory. */ - mapstart = (main_map->l_addr - + (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1))); - if (main_map->l_map_start > mapstart) - main_map->l_map_start = mapstart; - - /* Also where it ends. */ - allocend = main_map->l_addr + ph->p_vaddr + ph->p_memsz; - if (main_map->l_map_end < allocend) - main_map->l_map_end = allocend; - if ((ph->p_flags & PF_X) && allocend > main_map->l_text_end) - main_map->l_text_end = allocend; - } - break; - - case PT_TLS: - if (ph->p_memsz > 0) - { - /* Note that in the case the dynamic linker we duplicate work - here since we read the PT_TLS entry already in - _dl_start_final. But the result is repeatable so do not - check for this special but unimportant case. */ - main_map->l_tls_blocksize = ph->p_memsz; - main_map->l_tls_align = ph->p_align; - if (ph->p_align == 0) - main_map->l_tls_firstbyte_offset = 0; - else - main_map->l_tls_firstbyte_offset = (ph->p_vaddr - & (ph->p_align - 1)); - main_map->l_tls_initimage_size = ph->p_filesz; - main_map->l_tls_initimage = (void *) ph->p_vaddr; - - /* This image gets the ID one. */ - GL(dl_tls_max_dtv_idx) = main_map->l_tls_modid = 1; - } - break; - - case PT_GNU_STACK: - GL(dl_stack_flags) = ph->p_flags; - break; - - case PT_GNU_RELRO: - main_map->l_relro_addr = ph->p_vaddr; - main_map->l_relro_size = ph->p_memsz; - break; - } - /* Process program headers again, but scan them backwards so - that PT_NOTE can be skipped if PT_GNU_PROPERTY exits. */ - for (ph = &phdr[phnum]; ph != phdr; --ph) - switch (ph[-1].p_type) - { - case PT_NOTE: - _dl_process_pt_note (main_map, -1, &ph[-1]); - break; - case PT_GNU_PROPERTY: - _dl_process_pt_gnu_property (main_map, -1, &ph[-1]); - break; - } - - /* Adjust the address of the TLS initialization image in case - the executable is actually an ET_DYN object. */ - if (main_map->l_tls_initimage != NULL) - main_map->l_tls_initimage - = (char *) main_map->l_tls_initimage + main_map->l_addr; - if (! main_map->l_map_end) - main_map->l_map_end = ~0; - if (! main_map->l_text_end) - main_map->l_text_end = ~0; - if (! GL(dl_rtld_map).l_libname && GL(dl_rtld_map).l_name) - { - /* We were invoked directly, so the program might not have a - PT_INTERP. */ - _dl_rtld_libname.name = GL(dl_rtld_map).l_name; - /* _dl_rtld_libname.next = NULL; Already zero. */ - GL(dl_rtld_map).l_libname = &_dl_rtld_libname; - } - else - assert (GL(dl_rtld_map).l_libname); /* How else did we get here? */ + bool has_interp = rtld_setup_main_map (main_map); /* If the current libname is different from the SONAME, add the latter as well. */ |