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Re: [PATCH 1/4] Set up the data structures for vDSO in libc.a
On Thu, Oct 04, 2012 at 02:16:47PM -0700, Roland McGrath wrote:
>
> > + [BZ #14557]
> > + * elf/dl-support.c: Include <assert.h>.
> > + (_dl_sysinfo_map): New.
> > + Incldue "get-dynamic-info.h" and "setup-vdso.h".
>
> Typo.
Fixed.
>
> > + (_dl_non_dynamic_init): Call setup_vdso.
> > + * elf/dynamic-link.h: Remove elf_get_dynamic_info.
> > + Include "get-dynamic-info.h".
> > + * elf/get-dynamic-info.h: New file.
>
> The usual thing to write is:
>
> * elf/dynamic-link.h (elf_get_dynamic_info): Moved to ...
> * elf/get-dynamic-info.h: ... this new file.
> * elf/dynamic-link.h: Include that.
>
> > + * elf/setup-vdso.h: Likewise.
> > + * elf/rtld.c: Include "setup-vdso.h".
> > + (dl_main): Call setup_vdso.
>
> * elf/rtld.c (dl_main): Break out vDSO setup code into ...
> * elf/setup-vdso.h (setup_vdso): ... this new file and function.
> * elf/rtld.c: Include that.
> (dl_main): Call setup_vdso.
Fixed.
>
> > diff --git a/elf/dl-support.c b/elf/dl-support.c
> > index 2bb468a..23c4e53 100644
> > --- a/elf/dl-support.c
> > +++ b/elf/dl-support.c
> > @@ -33,6 +33,7 @@
> > #include <unsecvars.h>
> > #include <hp-timing.h>
> > #include <stackinfo.h>
> > +#include <assert.h>
>
> There is no use of assert in this file, so this does not belong here.
> elf_get_dynamic_info uses assert, so get-dynamic-info.h should include it.
Fixed.
>
> > extern char *__progname;
> > char **_dl_argv = &__progname; /* This is checked for some error messages. */
> > @@ -161,6 +162,11 @@ uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
> > #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
> > /* Address of the ELF headers in the vsyscall page. */
> > const ElfW(Ehdr) *_dl_sysinfo_dso;
> > +
> > +struct link_map *_dl_sysinfo_map;
> > +
> > +#include "get-dynamic-info.h"
> > +#include "setup-vdso.h"
> > #endif
>
> These should be "# include" since they're inside one level of #if.
Fixed.
>
> > /* During the program run we must not modify the global data of
> > @@ -266,6 +272,14 @@ _dl_non_dynamic_init (void)
> >
> > _dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
> >
> > +#if defined HAVE_AUX_VECTOR \
> > + && (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO)
> > + /* Set up the data structures for the system-supplied DSO early,
> > + so they can influence _dl_init_paths. */
> > + if (GLRO(dl_sysinfo_dso) != NULL)
> > + setup_vdso ();
> > +#endif
>
> Why is the HAVE_AUX_VECTOR conditional there? It's not in the rtld.c
> instance. Since you're duplicating the #if and the if here, I think
> instead it should just be an unconditional:
>
> _dl_sysinfo_setup ();
>
> and have setup-vdso.h contain the common conditionalization.
Fixed. I kept setup_vdso name since it is always inlined. Otherwise,
it won't work in rtld.c.
>
> > +static inline void __attribute__ ((always_inline))
> > +# ifdef IS_IN_rtld
> > +setup_vdso (struct link_map *main_map, struct link_map ***first_preload)
> > +# else
> > +setup_vdso (void)
> > +# endif
>
> Just give it a single signature. The dl-support.c case can pass NULL for
> both arguments, and you can check that. The check should be optimized away.
>
The new patch has a single signature. But I have to check IS_IN_rtld
in setup_vdso since main_map and dl_rtld_map are only available in
rtld.c. I verified that the text section size of elf/rtld.os are the
same before and after the patch on x86-64 and i686. OK to install?
Thanks.
H.J.
---
elf/dl-support.c | 9 +++
elf/dynamic-link.h | 145 +-------------------------------------------
elf/get-dynamic-info.h | 161 +++++++++++++++++++++++++++++++++++++++++++++++++
elf/rtld.c | 96 +----------------------------
elf/setup-vdso.h | 119 ++++++++++++++++++++++++++++++++++++
6 files changed, 306 insertions(+), 238 deletions(-)
create mode 100644 ChangeLog.pr14557
create mode 100644 elf/get-dynamic-info.h
create mode 100644 elf/setup-vdso.h
[BZ #14557]
* elf/dl-support.c (_dl_sysinfo_map): New.
Include "get-dynamic-info.h" and "setup-vdso.h".
(_dl_non_dynamic_init): Call setup_vdso.
* elf/dynamic-link.h: Don't include <assert.h>.
(elf_get_dynamic_info): Moved to ...
* elf/get-dynamic-info.h: Here. New file.
* elf/dynamic-link.h: Include "get-dynamic-info.h".
* elf/rtld.c (dl_main): Break out vDSO setup code into ...
* elf/setup-vdso.h: Here. New file.
* elf/rtld.c: Include "setup-vdso.h".
(dl_main): Call setup_vdso.
diff --git a/elf/dl-support.c b/elf/dl-support.c
index 2bb468a..424ca6d 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -161,6 +161,11 @@ uintptr_t _dl_sysinfo = DL_SYSINFO_DEFAULT;
#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
/* Address of the ELF headers in the vsyscall page. */
const ElfW(Ehdr) *_dl_sysinfo_dso;
+
+struct link_map *_dl_sysinfo_map;
+
+# include "get-dynamic-info.h"
+# include "setup-vdso.h"
#endif
/* During the program run we must not modify the global data of
@@ -266,6 +271,10 @@ _dl_non_dynamic_init (void)
_dl_verbose = *(getenv ("LD_WARN") ?: "") == '\0' ? 0 : 1;
+ /* Set up the data structures for the system-supplied DSO early,
+ so they can influence _dl_init_paths. */
+ setup_vdso (NULL, NULL);
+
/* Initialize the data structures for the search paths for shared
objects. */
_dl_init_paths (getenv ("LD_LIBRARY_PATH"));
diff --git a/elf/dynamic-link.h b/elf/dynamic-link.h
index d982c52..ad30d23 100644
--- a/elf/dynamic-link.h
+++ b/elf/dynamic-link.h
@@ -42,7 +42,6 @@
int internal_function _dl_try_allocate_static_tls (struct link_map *map);
#include <elf.h>
-#include <assert.h>
#ifdef RESOLVE_MAP
/* We pass reloc_addr as a pointer to void, as opposed to a pointer to
@@ -88,149 +87,7 @@ elf_machine_lazy_rel (struct link_map *map,
#include <dl-machine.h>
-
-/* Read the dynamic section at DYN and fill in INFO with indices DT_*. */
-#ifndef RESOLVE_MAP
-static
-#else
-auto
-#endif
-inline void __attribute__ ((unused, always_inline))
-elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
-{
- ElfW(Dyn) *dyn = l->l_ld;
- ElfW(Dyn) **info;
-#if __ELF_NATIVE_CLASS == 32
- typedef Elf32_Word d_tag_utype;
-#elif __ELF_NATIVE_CLASS == 64
- typedef Elf64_Xword d_tag_utype;
-#endif
-
-#ifndef RTLD_BOOTSTRAP
- if (dyn == NULL)
- return;
-#endif
-
- info = l->l_info;
-
- while (dyn->d_tag != DT_NULL)
- {
- if ((d_tag_utype) dyn->d_tag < DT_NUM)
- info[dyn->d_tag] = dyn;
- else if (dyn->d_tag >= DT_LOPROC &&
- dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
- info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
- else if ((d_tag_utype) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
- info[VERSYMIDX (dyn->d_tag)] = dyn;
- else if ((d_tag_utype) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
- info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
- + DT_VERSIONTAGNUM] = dyn;
- else if ((d_tag_utype) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
- info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
- + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
- else if ((d_tag_utype) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
- info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
- + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
- ++dyn;
- }
-
-#define DL_RO_DYN_TEMP_CNT 8
-
-#ifndef DL_RO_DYN_SECTION
- /* Don't adjust .dynamic unnecessarily. */
- if (l->l_addr != 0)
- {
- ElfW(Addr) l_addr = l->l_addr;
- int cnt = 0;
-
-# define ADJUST_DYN_INFO(tag) \
- do \
- if (info[tag] != NULL) \
- { \
- if (temp) \
- { \
- temp[cnt].d_tag = info[tag]->d_tag; \
- temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr; \
- info[tag] = temp + cnt++; \
- } \
- else \
- info[tag]->d_un.d_ptr += l_addr; \
- } \
- while (0)
-
- ADJUST_DYN_INFO (DT_HASH);
- ADJUST_DYN_INFO (DT_PLTGOT);
- ADJUST_DYN_INFO (DT_STRTAB);
- ADJUST_DYN_INFO (DT_SYMTAB);
-# if ! ELF_MACHINE_NO_RELA
- ADJUST_DYN_INFO (DT_RELA);
-# endif
-# if ! ELF_MACHINE_NO_REL
- ADJUST_DYN_INFO (DT_REL);
-# endif
- ADJUST_DYN_INFO (DT_JMPREL);
- ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
- ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM
- + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM);
-# undef ADJUST_DYN_INFO
- assert (cnt <= DL_RO_DYN_TEMP_CNT);
- }
-#endif
- if (info[DT_PLTREL] != NULL)
- {
-#if ELF_MACHINE_NO_RELA
- assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
-#elif ELF_MACHINE_NO_REL
- assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
-#else
- assert (info[DT_PLTREL]->d_un.d_val == DT_REL
- || info[DT_PLTREL]->d_un.d_val == DT_RELA);
-#endif
- }
-#if ! ELF_MACHINE_NO_RELA
- if (info[DT_RELA] != NULL)
- assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
-# endif
-# if ! ELF_MACHINE_NO_REL
- if (info[DT_REL] != NULL)
- assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
-#endif
-#ifdef RTLD_BOOTSTRAP
- /* Only the bind now flags are allowed. */
- assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
- || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
- assert (info[DT_FLAGS] == NULL
- || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
- /* Flags must not be set for ld.so. */
- assert (info[DT_RUNPATH] == NULL);
- assert (info[DT_RPATH] == NULL);
-#else
- if (info[DT_FLAGS] != NULL)
- {
- /* Flags are used. Translate to the old form where available.
- Since these l_info entries are only tested for NULL pointers it
- is ok if they point to the DT_FLAGS entry. */
- l->l_flags = info[DT_FLAGS]->d_un.d_val;
-
- if (l->l_flags & DF_SYMBOLIC)
- info[DT_SYMBOLIC] = info[DT_FLAGS];
- if (l->l_flags & DF_TEXTREL)
- info[DT_TEXTREL] = info[DT_FLAGS];
- if (l->l_flags & DF_BIND_NOW)
- info[DT_BIND_NOW] = info[DT_FLAGS];
- }
- if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
- {
- l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
-
- if (l->l_flags_1 & DF_1_NOW)
- info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
- }
- if (info[DT_RUNPATH] != NULL)
- /* If both RUNPATH and RPATH are given, the latter is ignored. */
- info[DT_RPATH] = NULL;
-#endif
-}
+#include "get-dynamic-info.h"
#ifdef RESOLVE_MAP
diff --git a/elf/get-dynamic-info.h b/elf/get-dynamic-info.h
new file mode 100644
index 0000000..ffac75f
--- /dev/null
+++ b/elf/get-dynamic-info.h
@@ -0,0 +1,161 @@
+/* Read the dynamic section at DYN and fill in INFO with indices DT_*.
+ Copyright (C) 2012 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
+ <http://www.gnu.org/licenses/>. */
+
+#include <assert.h>
+
+#ifndef RESOLVE_MAP
+static
+#else
+auto
+#endif
+inline void __attribute__ ((unused, always_inline))
+elf_get_dynamic_info (struct link_map *l, ElfW(Dyn) *temp)
+{
+ ElfW(Dyn) *dyn = l->l_ld;
+ ElfW(Dyn) **info;
+#if __ELF_NATIVE_CLASS == 32
+ typedef Elf32_Word d_tag_utype;
+#elif __ELF_NATIVE_CLASS == 64
+ typedef Elf64_Xword d_tag_utype;
+#endif
+
+#ifndef RTLD_BOOTSTRAP
+ if (dyn == NULL)
+ return;
+#endif
+
+ info = l->l_info;
+
+ while (dyn->d_tag != DT_NULL)
+ {
+ if ((d_tag_utype) dyn->d_tag < DT_NUM)
+ info[dyn->d_tag] = dyn;
+ else if (dyn->d_tag >= DT_LOPROC &&
+ dyn->d_tag < DT_LOPROC + DT_THISPROCNUM)
+ info[dyn->d_tag - DT_LOPROC + DT_NUM] = dyn;
+ else if ((d_tag_utype) DT_VERSIONTAGIDX (dyn->d_tag) < DT_VERSIONTAGNUM)
+ info[VERSYMIDX (dyn->d_tag)] = dyn;
+ else if ((d_tag_utype) DT_EXTRATAGIDX (dyn->d_tag) < DT_EXTRANUM)
+ info[DT_EXTRATAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
+ + DT_VERSIONTAGNUM] = dyn;
+ else if ((d_tag_utype) DT_VALTAGIDX (dyn->d_tag) < DT_VALNUM)
+ info[DT_VALTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
+ + DT_VERSIONTAGNUM + DT_EXTRANUM] = dyn;
+ else if ((d_tag_utype) DT_ADDRTAGIDX (dyn->d_tag) < DT_ADDRNUM)
+ info[DT_ADDRTAGIDX (dyn->d_tag) + DT_NUM + DT_THISPROCNUM
+ + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM] = dyn;
+ ++dyn;
+ }
+
+#define DL_RO_DYN_TEMP_CNT 8
+
+#ifndef DL_RO_DYN_SECTION
+ /* Don't adjust .dynamic unnecessarily. */
+ if (l->l_addr != 0)
+ {
+ ElfW(Addr) l_addr = l->l_addr;
+ int cnt = 0;
+
+# define ADJUST_DYN_INFO(tag) \
+ do \
+ if (info[tag] != NULL) \
+ { \
+ if (temp) \
+ { \
+ temp[cnt].d_tag = info[tag]->d_tag; \
+ temp[cnt].d_un.d_ptr = info[tag]->d_un.d_ptr + l_addr; \
+ info[tag] = temp + cnt++; \
+ } \
+ else \
+ info[tag]->d_un.d_ptr += l_addr; \
+ } \
+ while (0)
+
+ ADJUST_DYN_INFO (DT_HASH);
+ ADJUST_DYN_INFO (DT_PLTGOT);
+ ADJUST_DYN_INFO (DT_STRTAB);
+ ADJUST_DYN_INFO (DT_SYMTAB);
+# if ! ELF_MACHINE_NO_RELA
+ ADJUST_DYN_INFO (DT_RELA);
+# endif
+# if ! ELF_MACHINE_NO_REL
+ ADJUST_DYN_INFO (DT_REL);
+# endif
+ ADJUST_DYN_INFO (DT_JMPREL);
+ ADJUST_DYN_INFO (VERSYMIDX (DT_VERSYM));
+ ADJUST_DYN_INFO (DT_ADDRTAGIDX (DT_GNU_HASH) + DT_NUM + DT_THISPROCNUM
+ + DT_VERSIONTAGNUM + DT_EXTRANUM + DT_VALNUM);
+# undef ADJUST_DYN_INFO
+ assert (cnt <= DL_RO_DYN_TEMP_CNT);
+ }
+#endif
+ if (info[DT_PLTREL] != NULL)
+ {
+#if ELF_MACHINE_NO_RELA
+ assert (info[DT_PLTREL]->d_un.d_val == DT_REL);
+#elif ELF_MACHINE_NO_REL
+ assert (info[DT_PLTREL]->d_un.d_val == DT_RELA);
+#else
+ assert (info[DT_PLTREL]->d_un.d_val == DT_REL
+ || info[DT_PLTREL]->d_un.d_val == DT_RELA);
+#endif
+ }
+#if ! ELF_MACHINE_NO_RELA
+ if (info[DT_RELA] != NULL)
+ assert (info[DT_RELAENT]->d_un.d_val == sizeof (ElfW(Rela)));
+# endif
+# if ! ELF_MACHINE_NO_REL
+ if (info[DT_REL] != NULL)
+ assert (info[DT_RELENT]->d_un.d_val == sizeof (ElfW(Rel)));
+#endif
+#ifdef RTLD_BOOTSTRAP
+ /* Only the bind now flags are allowed. */
+ assert (info[VERSYMIDX (DT_FLAGS_1)] == NULL
+ || (info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val & ~DF_1_NOW) == 0);
+ assert (info[DT_FLAGS] == NULL
+ || (info[DT_FLAGS]->d_un.d_val & ~DF_BIND_NOW) == 0);
+ /* Flags must not be set for ld.so. */
+ assert (info[DT_RUNPATH] == NULL);
+ assert (info[DT_RPATH] == NULL);
+#else
+ if (info[DT_FLAGS] != NULL)
+ {
+ /* Flags are used. Translate to the old form where available.
+ Since these l_info entries are only tested for NULL pointers it
+ is ok if they point to the DT_FLAGS entry. */
+ l->l_flags = info[DT_FLAGS]->d_un.d_val;
+
+ if (l->l_flags & DF_SYMBOLIC)
+ info[DT_SYMBOLIC] = info[DT_FLAGS];
+ if (l->l_flags & DF_TEXTREL)
+ info[DT_TEXTREL] = info[DT_FLAGS];
+ if (l->l_flags & DF_BIND_NOW)
+ info[DT_BIND_NOW] = info[DT_FLAGS];
+ }
+ if (info[VERSYMIDX (DT_FLAGS_1)] != NULL)
+ {
+ l->l_flags_1 = info[VERSYMIDX (DT_FLAGS_1)]->d_un.d_val;
+
+ if (l->l_flags_1 & DF_1_NOW)
+ info[DT_BIND_NOW] = info[VERSYMIDX (DT_FLAGS_1)];
+ }
+ if (info[DT_RUNPATH] != NULL)
+ /* If both RUNPATH and RPATH are given, the latter is ignored. */
+ info[DT_RPATH] = NULL;
+#endif
+}
diff --git a/elf/rtld.c b/elf/rtld.c
index 8a02645..b0126e5 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -873,6 +873,7 @@ security_init (void)
_dl_random = NULL;
}
+#include "setup-vdso.h"
/* The library search path. */
static const char *library_path attribute_relro;
@@ -1329,102 +1330,9 @@ of this helper program; chances are you did not intend to run this program.\n\
}
struct link_map **first_preload = &GL(dl_rtld_map).l_next;
-#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
/* Set up the data structures for the system-supplied DSO early,
so they can influence _dl_init_paths. */
- if (GLRO(dl_sysinfo_dso) != NULL)
- {
- /* Do an abridged version of the work _dl_map_object_from_fd would do
- to map in the object. It's already mapped and prelinked (and
- better be, since it's read-only and so we couldn't relocate it).
- We just want our data structures to describe it as if we had just
- mapped and relocated it normally. */
- struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
- 0, LM_ID_BASE);
- if (__builtin_expect (l != NULL, 1))
- {
- static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
-
- l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
- + GLRO(dl_sysinfo_dso)->e_phoff);
- l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
- for (uint_fast16_t i = 0; i < l->l_phnum; ++i)
- {
- const ElfW(Phdr) *const ph = &l->l_phdr[i];
- if (ph->p_type == PT_DYNAMIC)
- {
- l->l_ld = (void *) ph->p_vaddr;
- l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
- }
- else if (ph->p_type == PT_LOAD)
- {
- if (! l->l_addr)
- l->l_addr = ph->p_vaddr;
- if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)
- l->l_map_end = ph->p_vaddr + ph->p_memsz;
- if ((ph->p_flags & PF_X)
- && ph->p_vaddr + ph->p_memsz >= l->l_text_end)
- l->l_text_end = ph->p_vaddr + ph->p_memsz;
- }
- else
- /* There must be no TLS segment. */
- assert (ph->p_type != PT_TLS);
- }
- l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);
- l->l_addr = l->l_map_start - l->l_addr;
- l->l_map_end += l->l_addr;
- l->l_text_end += l->l_addr;
- l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
- elf_get_dynamic_info (l, dyn_temp);
- _dl_setup_hash (l);
- l->l_relocated = 1;
-
- /* The vDSO is always used. */
- l->l_used = 1;
-
- /* Initialize l_local_scope to contain just this map. This allows
- the use of dl_lookup_symbol_x to resolve symbols within the vdso.
- So we create a single entry list pointing to l_real as its only
- element */
- l->l_local_scope[0]->r_nlist = 1;
- l->l_local_scope[0]->r_list = &l->l_real;
-
- /* Now that we have the info handy, use the DSO image's soname
- so this object can be looked up by name. Note that we do not
- set l_name here. That field gives the file name of the DSO,
- and this DSO is not associated with any file. */
- if (l->l_info[DT_SONAME] != NULL)
- {
- /* Work around a kernel problem. The kernel cannot handle
- addresses in the vsyscall DSO pages in writev() calls. */
- const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB])
- + l->l_info[DT_SONAME]->d_un.d_val);
- size_t len = strlen (dsoname);
- char *copy = malloc (len);
- if (copy == NULL)
- _dl_fatal_printf ("out of memory\n");
- l->l_libname->name = l->l_name = memcpy (copy, dsoname, len);
- }
-
- /* Add the vDSO to the object list. */
- _dl_add_to_namespace_list (l, LM_ID_BASE);
-
- /* Rearrange the list so this DSO appears after rtld_map. */
- assert (l->l_next == NULL);
- assert (l->l_prev == main_map);
- GL(dl_rtld_map).l_next = l;
- l->l_prev = &GL(dl_rtld_map);
- first_preload = &l->l_next;
-
- /* We have a prelinked DSO preloaded by the system. */
- GLRO(dl_sysinfo_map) = l;
-# ifdef NEED_DL_SYSINFO
- if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT)
- GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr;
-# endif
- }
- }
-#endif
+ setup_vdso (main_map, &first_preload);
#ifdef DL_SYSDEP_OSCHECK
DL_SYSDEP_OSCHECK (_dl_fatal_printf);
diff --git a/elf/setup-vdso.h b/elf/setup-vdso.h
new file mode 100644
index 0000000..1b969a0
--- /dev/null
+++ b/elf/setup-vdso.h
@@ -0,0 +1,119 @@
+/* Set up the data structures for the system-supplied DSO.
+ Copyright (C) 2012 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
+ <http://www.gnu.org/licenses/>. */
+
+static inline void __attribute__ ((always_inline))
+setup_vdso (struct link_map *main_map __attribute__ ((unused)),
+ struct link_map ***first_preload __attribute__ ((unused)))
+{
+#if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO
+ if (GLRO(dl_sysinfo_dso) == NULL)
+ return;
+
+ /* Do an abridged version of the work _dl_map_object_from_fd would do
+ to map in the object. It's already mapped and prelinked (and
+ better be, since it's read-only and so we couldn't relocate it).
+ We just want our data structures to describe it as if we had just
+ mapped and relocated it normally. */
+ struct link_map *l = _dl_new_object ((char *) "", "", lt_library, NULL,
+ 0, LM_ID_BASE);
+ if (__builtin_expect (l != NULL, 1))
+ {
+ static ElfW(Dyn) dyn_temp[DL_RO_DYN_TEMP_CNT] attribute_relro;
+
+ l->l_phdr = ((const void *) GLRO(dl_sysinfo_dso)
+ + GLRO(dl_sysinfo_dso)->e_phoff);
+ l->l_phnum = GLRO(dl_sysinfo_dso)->e_phnum;
+ for (uint_fast16_t i = 0; i < l->l_phnum; ++i)
+ {
+ const ElfW(Phdr) *const ph = &l->l_phdr[i];
+ if (ph->p_type == PT_DYNAMIC)
+ {
+ l->l_ld = (void *) ph->p_vaddr;
+ l->l_ldnum = ph->p_memsz / sizeof (ElfW(Dyn));
+ }
+ else if (ph->p_type == PT_LOAD)
+ {
+ if (! l->l_addr)
+ l->l_addr = ph->p_vaddr;
+ if (ph->p_vaddr + ph->p_memsz >= l->l_map_end)
+ l->l_map_end = ph->p_vaddr + ph->p_memsz;
+ if ((ph->p_flags & PF_X)
+ && ph->p_vaddr + ph->p_memsz >= l->l_text_end)
+ l->l_text_end = ph->p_vaddr + ph->p_memsz;
+ }
+ else
+ /* There must be no TLS segment. */
+ assert (ph->p_type != PT_TLS);
+ }
+ l->l_map_start = (ElfW(Addr)) GLRO(dl_sysinfo_dso);
+ l->l_addr = l->l_map_start - l->l_addr;
+ l->l_map_end += l->l_addr;
+ l->l_text_end += l->l_addr;
+ l->l_ld = (void *) ((ElfW(Addr)) l->l_ld + l->l_addr);
+ elf_get_dynamic_info (l, dyn_temp);
+ _dl_setup_hash (l);
+ l->l_relocated = 1;
+
+ /* The vDSO is always used. */
+ l->l_used = 1;
+
+ /* Initialize l_local_scope to contain just this map. This allows
+ the use of dl_lookup_symbol_x to resolve symbols within the vdso.
+ So we create a single entry list pointing to l_real as its only
+ element */
+ l->l_local_scope[0]->r_nlist = 1;
+ l->l_local_scope[0]->r_list = &l->l_real;
+
+ /* Now that we have the info handy, use the DSO image's soname
+ so this object can be looked up by name. Note that we do not
+ set l_name here. That field gives the file name of the DSO,
+ and this DSO is not associated with any file. */
+ if (l->l_info[DT_SONAME] != NULL)
+ {
+ /* Work around a kernel problem. The kernel cannot handle
+ addresses in the vsyscall DSO pages in writev() calls. */
+ const char *dsoname = ((char *) D_PTR (l, l_info[DT_STRTAB])
+ + l->l_info[DT_SONAME]->d_un.d_val);
+ size_t len = strlen (dsoname);
+ char *copy = malloc (len);
+ if (copy == NULL)
+ _dl_fatal_printf ("out of memory\n");
+ l->l_libname->name = l->l_name = memcpy (copy, dsoname, len);
+ }
+
+ /* Add the vDSO to the object list. */
+ _dl_add_to_namespace_list (l, LM_ID_BASE);
+
+# ifdef IS_IN_rtld
+ /* Rearrange the list so this DSO appears after rtld_map. */
+ assert (l->l_next == NULL);
+ assert (l->l_prev == main_map);
+ GL(dl_rtld_map).l_next = l;
+ l->l_prev = &GL(dl_rtld_map);
+ *first_preload = &l->l_next;
+# endif
+
+ /* We have a prelinked DSO preloaded by the system. */
+ GLRO(dl_sysinfo_map) = l;
+# ifdef NEED_DL_SYSINFO
+ if (GLRO(dl_sysinfo) == DL_SYSINFO_DEFAULT)
+ GLRO(dl_sysinfo) = GLRO(dl_sysinfo_dso)->e_entry + l->l_addr;
+# endif
+ }
+#endif
+}
--
1.7.11.4