diff options
Diffstat (limited to 'elf/dl-fptr.c')
| -rw-r--r-- | elf/dl-fptr.c | 322 |
1 files changed, 0 insertions, 322 deletions
diff --git a/elf/dl-fptr.c b/elf/dl-fptr.c deleted file mode 100644 index 575406ae44..0000000000 --- a/elf/dl-fptr.c +++ /dev/null @@ -1,322 +0,0 @@ -/* Manage function descriptors. Generic version. - Copyright (C) 1999-2024 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - <https://www.gnu.org/licenses/>. */ - -#include <libintl.h> -#include <unistd.h> -#include <string.h> -#include <sys/param.h> -#include <sys/mman.h> -#include <link.h> -#include <ldsodefs.h> -#include <elf/dynamic-link.h> -#include <dl-fptr.h> -#include <dl-unmap-segments.h> -#include <atomic.h> - -#ifndef ELF_MACHINE_BOOT_FPTR_TABLE_LEN -/* ELF_MACHINE_BOOT_FPTR_TABLE_LEN should be greater than the number of - dynamic symbols in ld.so. */ -# define ELF_MACHINE_BOOT_FPTR_TABLE_LEN 256 -#endif - -#ifndef ELF_MACHINE_LOAD_ADDRESS -# error "ELF_MACHINE_LOAD_ADDRESS is not defined." -#endif - -#ifndef COMPARE_AND_SWAP -# define COMPARE_AND_SWAP(ptr, old, new) \ - (catomic_compare_and_exchange_bool_acq (ptr, new, old) == 0) -#endif - -ElfW(Addr) _dl_boot_fptr_table [ELF_MACHINE_BOOT_FPTR_TABLE_LEN]; - -static struct local - { - struct fdesc_table *root; - struct fdesc *free_list; - unsigned int npages; /* # of pages to allocate */ - /* the next to members MUST be consecutive! */ - struct fdesc_table boot_table; - struct fdesc boot_fdescs[1024]; - } -local = - { - .root = &local.boot_table, - .npages = 2, - .boot_table = - { - .len = sizeof (local.boot_fdescs) / sizeof (local.boot_fdescs[0]), - .first_unused = 0 - } - }; - -/* Create a new fdesc table and return a pointer to the first fdesc - entry. The fdesc lock must have been acquired already. */ - -static struct fdesc_table * -new_fdesc_table (struct local *l, size_t *size) -{ - size_t old_npages = l->npages; - size_t new_npages = old_npages + old_npages; - struct fdesc_table *new_table; - - /* If someone has just created a new table, we return NULL to tell - the caller to use the new table. */ - if (! COMPARE_AND_SWAP (&l->npages, old_npages, new_npages)) - return (struct fdesc_table *) NULL; - - *size = old_npages * GLRO(dl_pagesize); - new_table = __mmap (NULL, *size, - PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0); - if (new_table == MAP_FAILED) - _dl_signal_error (errno, NULL, NULL, - N_("cannot map pages for fdesc table")); - - new_table->len - = (*size - sizeof (*new_table)) / sizeof (struct fdesc); - new_table->first_unused = 1; - return new_table; -} - - -static ElfW(Addr) -make_fdesc (ElfW(Addr) ip, ElfW(Addr) gp) -{ - struct fdesc *fdesc = NULL; - struct fdesc_table *root; - unsigned int old; - struct local *l; - - ELF_MACHINE_LOAD_ADDRESS (l, local); - - retry: - root = l->root; - while (1) - { - old = root->first_unused; - if (old >= root->len) - break; - else if (COMPARE_AND_SWAP (&root->first_unused, old, old + 1)) - { - fdesc = &root->fdesc[old]; - goto install; - } - } - - if (l->free_list) - { - /* Get it from free-list. */ - do - { - fdesc = l->free_list; - if (fdesc == NULL) - goto retry; - } - while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list, - (ElfW(Addr)) fdesc, fdesc->ip)); - } - else - { - /* Create a new fdesc table. */ - size_t size; - struct fdesc_table *new_table = new_fdesc_table (l, &size); - - if (new_table == NULL) - goto retry; - - new_table->next = root; - if (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->root, - (ElfW(Addr)) root, - (ElfW(Addr)) new_table)) - { - /* Someone has just installed a new table. Return NULL to - tell the caller to use the new table. */ - __munmap (new_table, size); - goto retry; - } - - /* Note that the first entry was reserved while allocating the - memory for the new page. */ - fdesc = &new_table->fdesc[0]; - } - - install: - fdesc->ip = ip; - fdesc->gp = gp; - - return (ElfW(Addr)) fdesc; -} - - -static inline ElfW(Addr) * __attribute__ ((always_inline)) -make_fptr_table (struct link_map *map) -{ - const ElfW(Sym) *symtab - = (const void *) D_PTR (map, l_info[DT_SYMTAB]); - const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]); - ElfW(Addr) *fptr_table; - size_t size; - size_t len; - - /* XXX Apparently the only way to find out the size of the dynamic - symbol section is to assume that the string table follows right - afterwards... */ - len = ((strtab - (char *) symtab) - / map->l_info[DT_SYMENT]->d_un.d_val); - size = ((len * sizeof (fptr_table[0]) + GLRO(dl_pagesize) - 1) - & -GLRO(dl_pagesize)); - /* XXX We don't support here in the moment systems without MAP_ANON. - There probably are none for IA-64. In case this is proven wrong - we will have to open /dev/null here and use the file descriptor - instead of the hard-coded -1. */ - fptr_table = __mmap (NULL, size, - PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, - -1, 0); - if (fptr_table == MAP_FAILED) - _dl_signal_error (errno, NULL, NULL, - N_("cannot map pages for fptr table")); - - if (COMPARE_AND_SWAP ((ElfW(Addr) *) &map->l_mach.fptr_table, - (ElfW(Addr)) NULL, (ElfW(Addr)) fptr_table)) - map->l_mach.fptr_table_len = len; - else - __munmap (fptr_table, len * sizeof (fptr_table[0])); - - return map->l_mach.fptr_table; -} - - -ElfW(Addr) -_dl_make_fptr (struct link_map *map, const ElfW(Sym) *sym, - ElfW(Addr) ip) -{ - ElfW(Addr) *ftab = map->l_mach.fptr_table; - const ElfW(Sym) *symtab; - Elf_Symndx symidx; - struct local *l; - - if (__glibc_unlikely (ftab == NULL)) - ftab = make_fptr_table (map); - - symtab = (const void *) D_PTR (map, l_info[DT_SYMTAB]); - symidx = sym - symtab; - - if (symidx >= map->l_mach.fptr_table_len) - _dl_signal_error (0, NULL, NULL, - N_("internal error: symidx out of range of fptr table")); - - while (ftab[symidx] == 0) - { - /* GOT has already been relocated in elf_get_dynamic_info - - don't try to relocate it again. */ - ElfW(Addr) fdesc - = make_fdesc (ip, map->l_info[DT_PLTGOT]->d_un.d_ptr); - - if (__builtin_expect (COMPARE_AND_SWAP (&ftab[symidx], (ElfW(Addr)) NULL, - fdesc), 1)) - { - /* No one has updated the entry and the new function - descriptor has been installed. */ -#if 0 - const char *strtab - = (const void *) D_PTR (map, l_info[DT_STRTAB]); - - ELF_MACHINE_LOAD_ADDRESS (l, local); - if (l->root != &l->boot_table - || l->boot_table.first_unused > 20) - _dl_debug_printf ("created fdesc symbol `%s' at %lx\n", - strtab + sym->st_name, ftab[symidx]); -#endif - break; - } - else - { - /* We created a duplicated function descriptor. We put it on - free-list. */ - struct fdesc *f = (struct fdesc *) fdesc; - - ELF_MACHINE_LOAD_ADDRESS (l, local); - - do - f->ip = (ElfW(Addr)) l->free_list; - while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &l->free_list, - f->ip, fdesc)); - } - } - - return ftab[symidx]; -} - - -void -_dl_unmap (struct link_map *map) -{ - ElfW(Addr) *ftab = map->l_mach.fptr_table; - struct fdesc *head = NULL, *tail = NULL; - size_t i; - - _dl_unmap_segments (map); - - if (ftab == NULL) - return; - - /* String together the fdesc structures that are being freed. */ - for (i = 0; i < map->l_mach.fptr_table_len; ++i) - { - if (ftab[i]) - { - *(struct fdesc **) ftab[i] = head; - head = (struct fdesc *) ftab[i]; - if (tail == NULL) - tail = head; - } - } - - /* Prepend the new list to the free_list: */ - if (tail) - do - tail->ip = (ElfW(Addr)) local.free_list; - while (! COMPARE_AND_SWAP ((ElfW(Addr) *) &local.free_list, - tail->ip, (ElfW(Addr)) head)); - - __munmap (ftab, (map->l_mach.fptr_table_len - * sizeof (map->l_mach.fptr_table[0]))); - - map->l_mach.fptr_table = NULL; -} - - -ElfW(Addr) -_dl_lookup_address (const void *address) -{ - ElfW(Addr) addr = (ElfW(Addr)) address; - struct fdesc_table *t; - unsigned long int i; - - for (t = local.root; t != NULL; t = t->next) - { - i = (struct fdesc *) addr - &t->fdesc[0]; - if (i < t->first_unused && addr == (ElfW(Addr)) &t->fdesc[i]) - { - addr = t->fdesc[i].ip; - break; - } - } - - return addr; -} |