/* Relocate a shared object and resolve its references to other loaded objects.
- Copyright (C) 1995,96,97,98,99,2000 Free Software Foundation, Inc.
+ Copyright (C) 1995-2019 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 Library General Public License as
- published by the Free Software Foundation; either version 2 of the
- License, or (at your option) any later version.
+ 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
- Library General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU Library General Public
- License along with the GNU C Library; see the file COPYING.LIB. If not,
- write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
#include <errno.h>
+#include <libintl.h>
#include <stdlib.h>
#include <unistd.h>
#include <ldsodefs.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. */
+#ifdef SHARED
+# define bump_num_cache_relocations() ++GL(dl_num_cache_relocations)
+#else
+# define bump_num_cache_relocations() ((void) 0)
+#endif
+
+
+/* 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. */
+int
+_dl_try_allocate_static_tls (struct link_map *map)
+{
+ /* 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))
+ {
+ fail:
+ return -1;
+ }
+
+#if TLS_TCB_AT_TP
+ size_t freebytes = GL(dl_tls_static_size) - GL(dl_tls_static_used);
+ if (freebytes < TLS_TCB_SIZE)
+ goto fail;
+ freebytes -= TLS_TCB_SIZE;
+
+ size_t blsize = map->l_tls_blocksize + map->l_tls_firstbyte_offset;
+ if (freebytes < blsize)
+ goto fail;
+
+ 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);
+
+ map->l_tls_offset = GL(dl_tls_static_used) = offset;
+#elif TLS_DTV_AT_TP
+ /* 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 > GL(dl_tls_static_size))
+ goto fail;
+
+ 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"
+#endif
+
+ /* If the object is not yet relocated we cannot initialize the
+ static TLS region. Delay it. */
+ if (map->l_real->l_relocated)
+ {
+#ifdef SHARED
+ if (__builtin_expect (THREAD_DTV()[0].counter != GL(dl_tls_generation),
+ 0))
+ /* Update the slot information data for at least the generation of
+ the DSO we are allocating data for. */
+ (void) _dl_update_slotinfo (map->l_tls_modid);
+#endif
+
+ GL(dl_init_static_tls) (map);
+ }
+ else
+ map->l_need_tls_init = 1;
+
+ return 0;
+}
+
+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))
+ {
+ _dl_signal_error (0, map->l_name, NULL, N_("\
+cannot allocate memory in static TLS block"));
+ }
+}
+
+/* Initialize static TLS area and DTV for current (only) thread.
+ libpthread implementations should provide their own hook
+ to handle all threads. */
+void
+_dl_nothread_init_static_tls (struct link_map *map)
+{
+#if TLS_TCB_AT_TP
+ void *dest = (char *) THREAD_SELF - map->l_tls_offset;
+#elif TLS_DTV_AT_TP
+ void *dest = (char *) THREAD_SELF + map->l_tls_offset + TLS_PRE_TCB_SIZE;
+#else
+# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
+#endif
+
+ /* 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);
+}
+
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
+ {
+ caddr_t start;
+ size_t len;
+ int prot;
+ struct textrels *next;
+ } *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
+ /* If we are auditing, install the same handlers we need for profiling. */
+ if ((reloc_mode & __RTLD_AUDIT) == 0)
+ consider_profiling |= GLRO(dl_audit) != NULL;
+#elif defined PROF
+ /* Never use dynamic linker profiling for gprof profiling code. */
+# define consider_profiling 0
+#endif
+
if (l->l_relocated)
return;
/* If DT_BIND_NOW is set relocate all references in this object. We
do not do this if we are profiling, of course. */
- if (!consider_profiling && l->l_info[DT_BIND_NOW])
+ // XXX Correct for auditing?
+ if (!consider_profiling
+ && __builtin_expect (l->l_info[DT_BIND_NOW] != NULL, 0))
lazy = 0;
- if (__builtin_expect (_dl_debug_reloc, 0))
- _dl_debug_message (1, "\nrelocation processing: ",
- l->l_name[0] ? l->l_name : _dl_argv[0],
- lazy ? " (lazy)\n" : "\n", NULL);
+ if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_RELOC))
+ _dl_debug_printf ("\nrelocation processing: %s%s\n",
+ DSO_FILENAME (l->l_name), lazy ? " (lazy)" : "");
- if (__builtin_expect (l->l_info[DT_TEXTREL] != NULL, 0))
+ /* 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 (__glibc_unlikely (l->l_info[DT_TEXTREL] != NULL))
{
/* Bletch. We must make read-only segments writable
long enough to relocate them. */
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 (__mprotect (mapstart, mapend - mapstart,
- PROT_READ|PROT_WRITE) < 0)
- _dl_signal_error (errno, l->l_name,
- "cannot make segment writable for relocation");
+ struct textrels *newp;
+
+ newp = (struct textrels *) alloca (sizeof (*newp));
+ 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;
+
+ 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;
+
+ 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;
}
}
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, flags) \
- (ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
- ? ((version) != NULL && (version)->hash != 0 \
- ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, l, (ref), \
- scope, (version), (flags)) \
- : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), scope, \
- (flags))) \
+#define RESOLVE_MAP(ref, version, r_type) \
+ ((ELFW(ST_BIND) ((*ref)->st_info) != STB_LOCAL \
+ && __glibc_likely (!dl_symbol_visibility_binds_local_p (*ref))) \
+ ? ((__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; \
+ if ((version) != NULL && (version)->hash != 0) \
+ v = (version); \
+ _lr = _dl_lookup_symbol_x (strtab + (*ref)->st_name, l, (ref), \
+ scope, v, _tc, \
+ DL_LOOKUP_ADD_DEPENDENCY, NULL); \
+ l->l_lookup_cache.ret = (*ref); \
+ l->l_lookup_cache.value = _lr; })) \
: l)
-#define RESOLVE(ref, version, flags) \
- (__builtin_expect (ELFW(ST_VISIBILITY) ((*ref)->st_other), 0) == 0 \
- ? ((version) != NULL && (version)->hash != 0 \
- ? _dl_lookup_versioned_symbol (strtab + (*ref)->st_name, l, (ref), \
- scope, (version), (flags)) \
- : _dl_lookup_symbol (strtab + (*ref)->st_name, l, (ref), scope, \
- (flags))) \
- : l->l_addr)
#include "dynamic-link.h"
- ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling);
- if (__builtin_expect (_dl_profile != NULL, 0))
+ ELF_DYNAMIC_RELOCATE (l, lazy, consider_profiling, skip_ifunc);
+
+#ifndef PROF
+ if (__glibc_unlikely (consider_profiling)
+ && l->l_info[DT_PLTRELSZ] != NULL)
{
/* Allocate the array which will contain the already found
- relocations. */
- l->l_reloc_result =
- (ElfW(Addr) *) calloc (sizeof (ElfW(Addr)),
- l->l_info[DT_PLTRELSZ]->d_un.d_val);
+ relocations. If the shared object lacks a PLT (for example
+ if it only contains lead function) the l_info[DT_PLTRELSZ]
+ will be NULL. */
+ 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);
+
if (l->l_reloc_result == NULL)
- _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
- "cannot allocate memory for profiling", NULL);
+ {
+ errstring = N_("\
+%s: out of memory to store relocation results for %s\n");
+ _dl_fatal_printf (errstring, RTLD_PROGNAME, l->l_name);
+ }
}
+#endif
}
/* 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)));
- extern unsigned char _dl_pf_to_prot[8];
- int prot;
-
- if ((PF_R | PF_W | PF_X) == 7
- && (PROT_READ | PROT_WRITE | PROT_EXEC) == 7)
- prot = _dl_pf_to_prot[ph->p_flags & (PF_R | PF_X)];
- else
- {
- prot = 0;
- if (ph->p_flags & PF_R)
- prot |= PROT_READ;
- if (ph->p_flags & PF_X)
- prot |= PROT_EXEC;
- }
-
- if (__mprotect (mapstart, mapend - mapstart, prot) < 0)
- _dl_signal_error (errno, l->l_name,
- "can't restore segment prot after reloc");
+ if (__mprotect (textrels->start, textrels->len, textrels->prot) < 0)
+ {
+ errstring = N_("cannot restore segment prot after reloc");
+ goto call_error;
+ }
#ifdef CLEAR_CACHE
- CLEAR_CACHE (mapstart, mapend);
+ CLEAR_CACHE (textrels->start, textrels->start + textrels->len);
#endif
- }
+
+ textrels = textrels->next;
}
+
+ /* In case we can protect the data now that the relocations are
+ done, do it. */
+ if (l->l_relro_size != 0)
+ _dl_protect_relro (l);
}
-#include "../stdio-common/_itoa.h"
-#define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
void
-internal_function
-_dl_reloc_bad_type (struct link_map *map, uint_fast8_t type, int plt)
+_dl_protect_relro (struct link_map *l)
{
- extern const char _itoa_lower_digits[];
- if (plt)
+ 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)
{
- char msg[] = "unexpected reloc type 0x??";
- msg[sizeof msg - 3] = DIGIT(type >> 8);
- msg[sizeof msg - 2] = DIGIT(type);
- _dl_signal_error (0, map->l_name, msg);
+ static const char errstring[] = N_("\
+cannot apply additional memory protection after relocation");
+ _dl_signal_error (errno, l->l_name, NULL, errstring);
}
- else
+}
+
+void
+__attribute_noinline__
+_dl_reloc_bad_type (struct link_map *map, unsigned int type, int plt)
+{
+#define DIGIT(b) _itoa_lower_digits[(b) & 0xf];
+
+ /* XXX We cannot translate these messages. */
+ static const char msg[2][32
+#if __ELF_NATIVE_CLASS == 64
+ + 6
+#endif
+ ] = { "unexpected reloc type 0x",
+ "unexpected PLT reloc type 0x" };
+ char msgbuf[sizeof (msg[0])];
+ char *cp;
+
+ cp = __stpcpy (msgbuf, msg[plt]);
+#if __ELF_NATIVE_CLASS == 64
+ if (__builtin_expect(type > 0xff, 0))
{
- char msg[] = "unexpected PLT reloc type 0x??";
- msg[sizeof msg - 3] = DIGIT(type >> 8);
- msg[sizeof msg - 2] = DIGIT(type);
- _dl_signal_error (0, map->l_name, msg);
+ *cp++ = DIGIT (type >> 28);
+ *cp++ = DIGIT (type >> 24);
+ *cp++ = DIGIT (type >> 20);
+ *cp++ = DIGIT (type >> 16);
+ *cp++ = DIGIT (type >> 12);
+ *cp++ = DIGIT (type >> 8);
}
+#endif
+ *cp++ = DIGIT (type >> 4);
+ *cp++ = DIGIT (type);
+ *cp = '\0';
+
+ _dl_signal_error (0, map->l_name, NULL, msgbuf);
}
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