/* Relocate a shared object and resolve its references to other loaded objects.
- Copyright (C) 1995-2004, 2005, 2006 Free Software Foundation, Inc.
+ Copyright (C) 1995-2023 Free Software Foundation, Inc.
+ Copyright The GNU Toolchain Authors.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
+ License along with the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
#include <errno.h>
#include <libintl.h>
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/types.h>
+#include <_itoa.h>
+#include <libc-pointer-arith.h>
#include "dynamic-link.h"
/* Statistics function. */
/* We are trying to perform a static TLS relocation in MAP, but it was
dynamically loaded. This can only work if there is enough surplus in
the static TLS area already allocated for each running thread. If this
- object's TLS segment is too big to fit, we fail. If it fits,
- we set MAP->l_tls_offset and return.
- This function intentionally does not return any value but signals error
- directly, as static TLS should be rare and code handling it should
- not be inlined as much as possible. */
-void
-internal_function __attribute_noinline__
-_dl_allocate_static_tls (struct link_map *map)
+ object's TLS segment is too big to fit, we fail with -1. If it fits,
+ we set MAP->l_tls_offset and return 0.
+ A portion of the surplus static TLS can be optionally used to optimize
+ dynamic TLS access (with TLSDESC or powerpc TLS optimizations).
+ If OPTIONAL is true then TLS is allocated for such optimization and
+ the caller must have a fallback in case the optional portion of surplus
+ TLS runs out. If OPTIONAL is false then the entire surplus TLS area is
+ considered and the allocation only fails if that runs out. */
+int
+_dl_try_allocate_static_tls (struct link_map *map, bool optional)
{
/* If we've already used the variable with dynamic access, or if the
alignment requirements are too high, fail. */
if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
- || map->l_tls_align > GL(dl_tls_static_align))
+ || map->l_tls_align > GLRO (dl_tls_static_align))
{
fail:
- _dl_signal_error (0, map->l_name, NULL, N_("\
-cannot allocate memory in static TLS block"));
+ return -1;
}
#if TLS_TCB_AT_TP
- size_t freebytes;
- size_t n;
- size_t blsize;
-
- freebytes = GL(dl_tls_static_size) - GL(dl_tls_static_used) - TLS_TCB_SIZE;
+ size_t freebytes = GLRO (dl_tls_static_size) - GL(dl_tls_static_used);
+ if (freebytes < TLS_TCB_SIZE)
+ goto fail;
+ freebytes -= TLS_TCB_SIZE;
- blsize = map->l_tls_blocksize + map->l_tls_firstbyte_offset;
+ size_t blsize = map->l_tls_blocksize + map->l_tls_firstbyte_offset;
if (freebytes < blsize)
goto fail;
- n = (freebytes - blsize) / map->l_tls_align;
+ size_t n = (freebytes - blsize) / map->l_tls_align;
- size_t offset = GL(dl_tls_static_used) + (freebytes - n * map->l_tls_align
- - map->l_tls_firstbyte_offset);
+ /* Account optional static TLS surplus usage. */
+ size_t use = freebytes - n * map->l_tls_align - map->l_tls_firstbyte_offset;
+ if (optional && use > GL(dl_tls_static_optional))
+ goto fail;
+ else if (optional)
+ GL(dl_tls_static_optional) -= use;
+
+ size_t offset = GL(dl_tls_static_used) + use;
map->l_tls_offset = GL(dl_tls_static_used) = offset;
#elif TLS_DTV_AT_TP
- size_t used;
- size_t check;
-
- size_t offset = roundup (GL(dl_tls_static_used), map->l_tls_align);
- used = offset + map->l_tls_blocksize;
- check = used;
/* dl_tls_static_used includes the TCB at the beginning. */
+ size_t offset = (ALIGN_UP(GL(dl_tls_static_used)
+ - map->l_tls_firstbyte_offset,
+ map->l_tls_align)
+ + map->l_tls_firstbyte_offset);
+ size_t used = offset + map->l_tls_blocksize;
+
+ if (used > GLRO (dl_tls_static_size))
+ goto fail;
- if (check > GL(dl_tls_static_size))
+ /* Account optional static TLS surplus usage. */
+ size_t use = used - GL(dl_tls_static_used);
+ if (optional && use > GL(dl_tls_static_optional))
goto fail;
+ else if (optional)
+ GL(dl_tls_static_optional) -= use;
map->l_tls_offset = offset;
+ map->l_tls_firstbyte_offset = GL(dl_tls_static_used);
GL(dl_tls_static_used) = used;
#else
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
(void) _dl_update_slotinfo (map->l_tls_modid);
#endif
- GL(dl_init_static_tls) (map);
+ dl_init_static_tls (map);
}
else
map->l_need_tls_init = 1;
+
+ return 0;
+}
+
+/* This function intentionally does not return any value but signals error
+ directly, as static TLS should be rare and code handling it should
+ not be inlined as much as possible. */
+void
+__attribute_noinline__
+_dl_allocate_static_tls (struct link_map *map)
+{
+ if (map->l_tls_offset == FORCED_DYNAMIC_TLS_OFFSET
+ || _dl_try_allocate_static_tls (map, false))
+ {
+ _dl_signal_error (0, map->l_name, NULL, N_("\
+cannot allocate memory in static TLS block"));
+ }
}
+#if !PTHREAD_IN_LIBC
/* Initialize static TLS area and DTV for current (only) thread.
libpthread implementations should provide their own hook
to handle all threads. */
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
#endif
- /* Fill in the DTV slot so that a later LD/GD access will find it. */
- dtv_t *dtv = THREAD_DTV ();
- assert (map->l_tls_modid <= dtv[-1].counter);
- dtv[map->l_tls_modid].pointer.val = dest;
- dtv[map->l_tls_modid].pointer.is_static = true;
-
/* Initialize the memory. */
memset (__mempcpy (dest, map->l_tls_initimage, map->l_tls_initimage_size),
'\0', map->l_tls_blocksize - map->l_tls_initimage_size);
}
+#endif /* !PTHREAD_IN_LIBC */
+static __always_inline lookup_t
+resolve_map (lookup_t l, struct r_scope_elem *scope[], const ElfW(Sym) **ref,
+ const struct r_found_version *version, unsigned long int r_type)
+{
+ if (ELFW(ST_BIND) ((*ref)->st_info) == STB_LOCAL
+ || __glibc_unlikely (dl_symbol_visibility_binds_local_p (*ref)))
+ return l;
+
+ if (__glibc_unlikely (*ref == l->l_lookup_cache.sym)
+ && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class)
+ {
+ bump_num_cache_relocations ();
+ *ref = l->l_lookup_cache.ret;
+ }
+ else
+ {
+ const int tc = elf_machine_type_class (r_type);
+ l->l_lookup_cache.type_class = tc;
+ l->l_lookup_cache.sym = *ref;
+ const char *undef_name
+ = (const char *) D_PTR (l, l_info[DT_STRTAB]) + (*ref)->st_name;
+ const struct r_found_version *v = NULL;
+ if (version != NULL && version->hash != 0)
+ v = version;
+ lookup_t lr = _dl_lookup_symbol_x (
+ undef_name, l, ref, scope, v, tc,
+ DL_LOOKUP_ADD_DEPENDENCY | DL_LOOKUP_FOR_RELOCATE, NULL);
+ l->l_lookup_cache.ret = *ref;
+ l->l_lookup_cache.value = lr;
+ }
+ return l->l_lookup_cache.value;
+}
+
+/* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
+#define RESOLVE_MAP resolve_map
+
+#include "dynamic-link.h"
void
_dl_relocate_object (struct link_map *l, struct r_scope_elem *scope[],
- int lazy, int consider_profiling)
+ int reloc_mode, int consider_profiling)
{
struct textrels
{
} *textrels = NULL;
/* Initialize it to make the compiler happy. */
const char *errstring = NULL;
+ int lazy = reloc_mode & RTLD_LAZY;
+ int skip_ifunc = reloc_mode & __RTLD_NOIFUNC;
#ifdef SHARED
+ bool consider_symbind = false;
/* If we are auditing, install the same handlers we need for profiling. */
- consider_profiling |= GLRO(dl_audit) != NULL;
+ if ((reloc_mode & __RTLD_AUDIT) == 0)
+ {
+ struct audit_ifaces *afct = GLRO(dl_audit);
+ for (unsigned int cnt = 0; cnt < GLRO(dl_naudit); ++cnt)
+ {
+ /* Profiling is needed only if PLT hooks are provided. */
+ if (afct->ARCH_LA_PLTENTER != NULL
+ || afct->ARCH_LA_PLTEXIT != NULL)
+ consider_profiling = 1;
+ if (afct->symbind != NULL)
+ consider_symbind = true;
+
+ afct = afct->next;
+ }
+ }
#elif defined PROF
/* Never use dynamic linker profiling for gprof profiling code. */
# define consider_profiling 0
+#else
+# define consider_symbind 0
#endif
if (l->l_relocated)
&& __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
lazy = 0;
- if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_RELOC, 0))
+ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_RELOC))
_dl_debug_printf ("\nrelocation processing: %s%s\n",
- l->l_name[0] ? l->l_name : rtld_progname,
- lazy ? " (lazy)" : "");
+ DSO_FILENAME (l->l_name), 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))
+ if (__glibc_unlikely (l->l_info[DT_TEXTREL] != NULL))
{
/* Bletch. We must make read-only segments writable
long enough to relocate them. */
struct textrels *newp;
newp = (struct textrels *) alloca (sizeof (*newp));
- newp->len = (((ph->p_vaddr + ph->p_memsz + GLRO(dl_pagesize) - 1)
- & ~(GLRO(dl_pagesize) - 1))
- - (ph->p_vaddr & ~(GLRO(dl_pagesize) - 1)));
- newp->start = ((ph->p_vaddr & ~(GLRO(dl_pagesize) - 1))
- + (caddr_t) l->l_addr);
+ newp->len = ALIGN_UP (ph->p_vaddr + ph->p_memsz, GLRO(dl_pagesize))
+ - ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize));
+ newp->start = PTR_ALIGN_DOWN (ph->p_vaddr, GLRO(dl_pagesize))
+ + (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;
newp->prot |= PROT_WRITE;
if (ph->p_flags & PF_X)
newp->prot |= PROT_EXEC;
-#endif
+
+ if (__mprotect (newp->start, newp->len, newp->prot|PROT_WRITE) < 0)
+ {
+ errstring = N_("cannot make segment writable for relocation");
+ call_error:
+ _dl_signal_error (errno, l->l_name, NULL, errstring);
+ }
+
newp->next = textrels;
textrels = newp;
}
{
/* Do the actual relocation of the object's GOT and other data. */
- /* String table object symbols. */
- const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
-
- /* This macro is used as a callback from the ELF_DYNAMIC_RELOCATE code. */
-#define RESOLVE_MAP(ref, version, r_type) \
- (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
- ? ((__builtin_expect ((*ref) == l->l_lookup_cache.sym, 0) \
- && elf_machine_type_class (r_type) == l->l_lookup_cache.type_class) \
- ? (bump_num_cache_relocations (), \
- (*ref) = l->l_lookup_cache.ret, \
- l->l_lookup_cache.value) \
- : ({ lookup_t _lr; \
- int _tc = elf_machine_type_class (r_type); \
- l->l_lookup_cache.type_class = _tc; \
- l->l_lookup_cache.sym = (*ref); \
- const struct r_found_version *v = NULL; \
- int flags = DL_LOOKUP_ADD_DEPENDENCY; \
- if ((version) != NULL && (version)->hash != 0) \
- { \
- v = (version); \
- flags = 0; \
- } \
- _lr = _dl_lookup_symbol_x (strtab + (*ref)->st_name, l, (ref), \
- scope, v, _tc, flags, NULL); \
- l->l_lookup_cache.ret = (*ref); \
- l->l_lookup_cache.value = _lr; })) \
- : l)
-
- /* This macro is used as a callback from elf_machine_rel{a,} when a
- static TLS reloc is about to be performed. Since (in dl-load.c) we
- permit dynamic loading of objects that might use such relocs, we
- have to check whether each use is actually doable. If the object
- whose TLS segment the reference resolves to was allocated space in
- the static TLS block at startup, then it's ok. Otherwise, we make
- an attempt to allocate it in surplus space on the fly. If that
- can't be done, we fall back to the error that DF_STATIC_TLS is
- intended to produce. */
-#define CHECK_STATIC_TLS(map, sym_map) \
- do { \
- if (__builtin_expect ((sym_map)->l_tls_offset == NO_TLS_OFFSET \
- || ((sym_map)->l_tls_offset \
- == FORCED_DYNAMIC_TLS_OFFSET), 0)) \
- _dl_allocate_static_tls (sym_map); \
- } while (0)
-
-#include "dynamic-link.h"
-
- ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
+ ELF_DYNAMIC_RELOCATE (l, scope, lazy, consider_profiling, skip_ifunc);
#ifndef PROF
- if (__builtin_expect (consider_profiling, 0))
+ if ((consider_profiling || consider_symbind)
+ && l->l_info[DT_PLTRELSZ] != 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]
will be NULL. */
- if (l->l_info[DT_PLTRELSZ] == NULL)
- {
- errstring = N_("%s: no PLTREL found in object %s\n");
- fatal:
- _dl_fatal_printf (errstring,
- rtld_progname ?: "<program name unknown>",
- l->l_name);
- }
+ size_t sizeofrel = l->l_info[DT_PLTREL]->d_un.d_val == DT_RELA
+ ? sizeof (ElfW(Rela))
+ : sizeof (ElfW(Rel));
+ size_t relcount = l->l_info[DT_PLTRELSZ]->d_un.d_val / sizeofrel;
+ l->l_reloc_result = calloc (sizeof (l->l_reloc_result[0]), relcount);
- l->l_reloc_result = calloc (sizeof (l->l_reloc_result[0]),
- l->l_info[DT_PLTRELSZ]->d_un.d_val);
if (l->l_reloc_result == NULL)
{
errstring = N_("\
%s: out of memory to store relocation results for %s\n");
- goto fatal;
+ _dl_fatal_printf (errstring, RTLD_PROGNAME, l->l_name);
}
}
#endif
goto call_error;
}
+#ifdef CLEAR_CACHE
+ CLEAR_CACHE (textrels->start, textrels->start + textrels->len);
+#endif
+
textrels = textrels->next;
}
}
-void internal_function
+void
_dl_protect_relro (struct link_map *l)
{
- ElfW(Addr) start = ((l->l_addr + l->l_relro_addr)
- & ~(GLRO(dl_pagesize) - 1));
- ElfW(Addr) end = ((l->l_addr + l->l_relro_addr + l->l_relro_size)
- & ~(GLRO(dl_pagesize) - 1));
-
+ ElfW(Addr) start = ALIGN_DOWN((l->l_addr
+ + l->l_relro_addr),
+ GLRO(dl_pagesize));
+ ElfW(Addr) end = ALIGN_DOWN((l->l_addr
+ + l->l_relro_addr
+ + l->l_relro_size),
+ GLRO(dl_pagesize));
if (start != end
&& __mprotect ((void *) start, end - start, PROT_READ) < 0)
{
}
void
-internal_function __attribute_noinline__
+__attribute_noinline__
_dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
{
- extern const char INTUSE(_itoa_lower_digits)[] attribute_hidden;
-#define DIGIT(b) INTUSE(_itoa_lower_digits)[(b) & 0xf];
+#define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
/* XXX We cannot translate these messages. */
static const char msg[2][32
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