From f133c09767993fddcdd790a361fd11d6410a84b2 Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Mon, 12 Nov 2001 21:04:45 +0000 Subject: [PATCH] Update. 2001-11-12 Ulrich Drepper * elf/dl-reloc.c (_dl_relocate_object): Avoid iterating over program header twice. Construct list with the needed information. --- ChangeLog | 5 +++ elf/dl-reloc.c | 99 ++++++++++++++++++++++++++++++---------------------------- 2 files changed, 56 insertions(+), 48 deletions(-) diff --git a/ChangeLog b/ChangeLog index dd3843b..bc96841 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2001-11-12 Ulrich Drepper + + * elf/dl-reloc.c (_dl_relocate_object): Avoid iterating over + program header twice. Construct list with the needed information. + 2001-11-10 Ulrich Drepper * po/ca.po: Update from translation team. diff --git a/elf/dl-reloc.c b/elf/dl-reloc.c index da964b7..4d4ca14 100644 --- a/elf/dl-reloc.c +++ b/elf/dl-reloc.c @@ -35,6 +35,16 @@ void _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], int lazy, int consider_profiling) { + struct textrels + { + caddr_t start; + size_t len; + int prot; + struct textrels *next; + } *textrels = NULL; + /* Initialize it to make the compiler happy. */ + const char *errstring = NULL; + if (l->l_relocated) return; @@ -48,6 +58,9 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], _dl_printf ("\nrelocation processing: %s%s\n", l->l_name[0] ? l->l_name : _dl_argv[0], lazy ? " (lazy)" : ""); + /* DT_TEXTREL is now in level 2 and might phase out at some time. + But we rewrite the DT_FLAGS entry to a DT_TEXTREL entry to make + testing easier and therefore it will be available at all time. */ if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0)) { /* Bletch. We must make read-only segments writable @@ -56,15 +69,36 @@ _dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[], for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph) if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0) { - caddr_t mapstart = ((caddr_t) l->l_addr + - (ph->p_vaddr & ~(_dl_pagesize - 1))); - caddr_t mapend = ((caddr_t) l->l_addr + - ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) - & ~(_dl_pagesize - 1))); - if (__builtin_expect (__mprotect (mapstart, mapend - mapstart, - PROT_READ|PROT_WRITE), 0) < 0) - _dl_signal_error (errno, l->l_name, NULL, N_("\ -cannot make segment writable for relocation")); + struct textrels *newp; + + newp = (struct textrels *) alloca (sizeof (*newp)); + newp->len = (((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) + & ~(_dl_pagesize - 1)) + - (ph->p_vaddr & ~(_dl_pagesize - 1))); + newp->start = ((ph->p_vaddr & ~(_dl_pagesize - 1)) + + (caddr_t) l->l_addr); + + if (__mprotect (newp->start, newp->len, PROT_READ|PROT_WRITE) < 0) + { + errstring = N_("cannot make segment writable for relocation"); + call_error: + _dl_signal_error (errno, l->l_name, NULL, errstring); + } + +#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7 + newp->prot = (PF_TO_PROT + >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf; +#else + newp->prot = 0; + if (ph->p_flags & PF_R) + newp->prot |= PROT_READ; + if (ph->p_flags & PF_W) + newp->prot |= PROT_WRITE; + if (ph->p_flags & PF_X) + newp->prot |= PROT_EXEC; +#endif + newp->next = textrels; + textrels = newp; } } @@ -122,8 +156,6 @@ cannot make segment writable for relocation")); if (__builtin_expect (consider_profiling, 0)) { - const char *errstring = NULL; - /* Allocate the array which will contain the already found relocations. If the shared object lacks a PLT (for example if it only contains lead function) the l_info[DT_PLTRELSZ] @@ -152,45 +184,16 @@ cannot make segment writable for relocation")); /* Mark the object so we know this work has been done. */ l->l_relocated = 1; - /* DT_TEXTREL is now in level 2 and might phase out at some time. - But we rewrite the DT_FLAGS entry to make testing easier and - therefore it will be available at all time. */ - if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0)) + /* Undo the segment protection changes. */ + while (__builtin_expect (textrels != NULL, 0)) { - /* Undo the protection change we made before relocating. */ - const ElfW(Phdr) *ph; - for (ph = l->l_phdr; ph < &l->l_phdr[l->l_phnum]; ++ph) - if (ph->p_type == PT_LOAD && (ph->p_flags & PF_W) == 0) - { - caddr_t mapstart = ((caddr_t) l->l_addr + - (ph->p_vaddr & ~(_dl_pagesize - 1))); - caddr_t mapend = ((caddr_t) l->l_addr + - ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1) - & ~(_dl_pagesize - 1))); - int prot; + if (__mprotect (textrels->start, textrels->len, textrels->prot) < 0) + { + errstring = N_("cannot restore segment prot after reloc"); + goto call_error; + } -#if (PF_R | PF_W | PF_X) == 7 && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7 - prot = (PF_TO_PROT - >> ((ph->p_flags & (PF_R | PF_W | PF_X)) * 4)) & 0xf; -#else - prot = 0; - if (ph->p_flags & PF_R) - prot |= PROT_READ; - if (ph->p_flags & PF_W) - prot |= PROT_WRITE; - if (ph->p_flags & PF_X) - prot |= PROT_EXEC; -#endif - - if (__builtin_expect (__mprotect (mapstart, mapend - mapstart, - prot), 0) < 0) - _dl_signal_error (errno, l->l_name, NULL, - N_("can't restore segment prot after reloc")); - -#ifdef CLEAR_CACHE - CLEAR_CACHE (mapstart, mapend); -#endif - } + textrels = textrels->next; } } -- 2.7.4