[v2,1/5] elf: Merge dl-sysdep.c into the Linux version

Message ID 5a97c0f8a98b24b29ddb334194b23341db71a9ae.1643886336.git.fweimer@redhat.com
State Committed
Commit 91c0a47ffb66e7cd802de870686465db3b3976a0
Headers
Series Linux: Auxiliary vector parsing cleanups |

Checks

Context Check Description
dj/TryBot-apply_patch success Patch applied to master at the time it was sent

Commit Message

Florian Weimer Feb. 3, 2022, 11:08 a.m. UTC
  The generic version is the de-facto Linux implementation.  It
requires an auxiliary vector, so Hurd does not use it.
---
 elf/dl-sysdep.c                     | 352 +---------------------------
 sysdeps/unix/sysv/linux/dl-sysdep.c | 347 ++++++++++++++++++++++++++-
 2 files changed, 337 insertions(+), 362 deletions(-)
  

Comments

Adhemerval Zanella Netto Feb. 8, 2022, 8:09 p.m. UTC | #1
On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote:
> The generic version is the de-facto Linux implementation.  It
> requires an auxiliary vector, so Hurd does not use it.

LGTM, thanks.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> ---
>  elf/dl-sysdep.c                     | 352 +---------------------------
>  sysdeps/unix/sysv/linux/dl-sysdep.c | 347 ++++++++++++++++++++++++++-
>  2 files changed, 337 insertions(+), 362 deletions(-)
> 
> diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
> index f1dba8ef24..7aa90ad6ee 100644
> --- a/elf/dl-sysdep.c
> +++ b/elf/dl-sysdep.c
> @@ -1,4 +1,4 @@
> -/* Operating system support for run-time dynamic linker.  Generic Unix version.
> +/* Operating system support for run-time dynamic linker.  Stub version.
>     Copyright (C) 1995-2022 Free Software Foundation, Inc.
>     This file is part of the GNU C Library.
>  
> @@ -16,352 +16,4 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -/* We conditionalize the whole of this file rather than simply eliding it
> -   from the static build, because other sysdeps/ versions of this file
> -   might define things needed by a static build.  */
> -
> -#ifdef SHARED
> -
> -#include <assert.h>
> -#include <elf.h>
> -#include <errno.h>
> -#include <fcntl.h>
> -#include <libintl.h>
> -#include <stdlib.h>
> -#include <string.h>
> -#include <unistd.h>
> -#include <sys/types.h>
> -#include <sys/stat.h>
> -#include <sys/mman.h>
> -#include <ldsodefs.h>
> -#include <_itoa.h>
> -#include <fpu_control.h>
> -
> -#include <entry.h>
> -#include <dl-machine.h>
> -#include <dl-procinfo.h>
> -#include <dl-osinfo.h>
> -#include <libc-internal.h>
> -#include <tls.h>
> -
> -#include <dl-tunables.h>
> -#include <dl-auxv.h>
> -#include <dl-hwcap-check.h>
> -
> -extern char **_environ attribute_hidden;
> -extern char _end[] attribute_hidden;
> -
> -/* Protect SUID program against misuse of file descriptors.  */
> -extern void __libc_check_standard_fds (void);
> -
> -int __libc_enable_secure attribute_relro = 0;
> -rtld_hidden_data_def (__libc_enable_secure)
> -/* This variable contains the lowest stack address ever used.  */
> -void *__libc_stack_end attribute_relro = NULL;
> -rtld_hidden_data_def(__libc_stack_end)
> -void *_dl_random attribute_relro = NULL;
> -
> -#ifndef DL_FIND_ARG_COMPONENTS
> -# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
> -  do {									      \
> -    void **_tmp;							      \
> -    (argc) = *(long int *) cookie;					      \
> -    (argv) = (char **) ((long int *) cookie + 1);			      \
> -    (envp) = (argv) + (argc) + 1;					      \
> -    for (_tmp = (void **) (envp); *_tmp; ++_tmp)			      \
> -      continue;								      \
> -    (auxp) = (void *) ++_tmp;						      \
> -  } while (0)
> -#endif
> -
> -#ifndef DL_STACK_END
> -# define DL_STACK_END(cookie) ((void *) (cookie))
> -#endif
> -
> -ElfW(Addr)
> -_dl_sysdep_start (void **start_argptr,
> -		  void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
> -				   ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
> -{
> -  const ElfW(Phdr) *phdr = NULL;
> -  ElfW(Word) phnum = 0;
> -  ElfW(Addr) user_entry;
> -  ElfW(auxv_t) *av;
> -#ifdef HAVE_AUX_SECURE
> -# define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
> -# define set_seen_secure() ((void) 0)
> -#else
> -  uid_t uid = 0;
> -  gid_t gid = 0;
> -  unsigned int seen = 0;
> -# define set_seen_secure() (seen = -1)
> -# ifdef HAVE_AUX_XID
> -#  define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
> -# else
> -#  define M(type) (1 << (type))
> -#  define set_seen(tag) seen |= M ((tag)->a_type)
> -# endif
> -#endif
> -#ifdef NEED_DL_SYSINFO
> -  uintptr_t new_sysinfo = 0;
> -#endif
> -
> -  __libc_stack_end = DL_STACK_END (start_argptr);
> -  DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ,
> -			  GLRO(dl_auxv));
> -
> -  user_entry = (ElfW(Addr)) ENTRY_POINT;
> -  GLRO(dl_platform) = NULL; /* Default to nothing known about the platform.  */
> -
> -  /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
> -  _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
> -		  "CONSTANT_MINSIGSTKSZ is constant");
> -  GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
> -
> -  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
> -    switch (av->a_type)
> -      {
> -      case AT_PHDR:
> -	phdr = (void *) av->a_un.a_val;
> -	break;
> -      case AT_PHNUM:
> -	phnum = av->a_un.a_val;
> -	break;
> -      case AT_PAGESZ:
> -	GLRO(dl_pagesize) = av->a_un.a_val;
> -	break;
> -      case AT_ENTRY:
> -	user_entry = av->a_un.a_val;
> -	break;
> -#ifndef HAVE_AUX_SECURE
> -      case AT_UID:
> -      case AT_EUID:
> -	uid ^= av->a_un.a_val;
> -	break;
> -      case AT_GID:
> -      case AT_EGID:
> -	gid ^= av->a_un.a_val;
> -	break;
> -#endif
> -      case AT_SECURE:
> -#ifndef HAVE_AUX_SECURE
> -	seen = -1;
> -#endif
> -	__libc_enable_secure = av->a_un.a_val;
> -	break;
> -      case AT_PLATFORM:
> -	GLRO(dl_platform) = (void *) av->a_un.a_val;
> -	break;
> -      case AT_HWCAP:
> -	GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
> -	break;
> -      case AT_HWCAP2:
> -	GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
> -	break;
> -      case AT_CLKTCK:
> -	GLRO(dl_clktck) = av->a_un.a_val;
> -	break;
> -      case AT_FPUCW:
> -	GLRO(dl_fpu_control) = av->a_un.a_val;
> -	break;
> -#ifdef NEED_DL_SYSINFO
> -      case AT_SYSINFO:
> -	new_sysinfo = av->a_un.a_val;
> -	break;
> -#endif
> -#ifdef NEED_DL_SYSINFO_DSO
> -      case AT_SYSINFO_EHDR:
> -	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
> -	break;
> -#endif
> -      case AT_RANDOM:
> -	_dl_random = (void *) av->a_un.a_val;
> -	break;
> -      case AT_MINSIGSTKSZ:
> -	GLRO(dl_minsigstacksize) = av->a_un.a_val;
> -	break;
> -      DL_PLATFORM_AUXV
> -      }
> -
> -  dl_hwcap_check ();
> -
> -#ifndef HAVE_AUX_SECURE
> -  if (seen != -1)
> -    {
> -      /* Fill in the values we have not gotten from the kernel through the
> -	 auxiliary vector.  */
> -# ifndef HAVE_AUX_XID
> -#  define SEE(UID, var, uid) \
> -   if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
> -      SEE (UID, uid, uid);
> -      SEE (EUID, uid, euid);
> -      SEE (GID, gid, gid);
> -      SEE (EGID, gid, egid);
> -# endif
> -
> -      /* If one of the two pairs of IDs does not match this is a setuid
> -	 or setgid run.  */
> -      __libc_enable_secure = uid | gid;
> -    }
> -#endif
> -
> -#ifndef HAVE_AUX_PAGESIZE
> -  if (GLRO(dl_pagesize) == 0)
> -    GLRO(dl_pagesize) = __getpagesize ();
> -#endif
> -
> -#ifdef NEED_DL_SYSINFO
> -  if (new_sysinfo != 0)
> -    {
> -# ifdef NEED_DL_SYSINFO_DSO
> -      /* Only set the sysinfo value if we also have the vsyscall DSO.  */
> -      if (GLRO(dl_sysinfo_dso) != 0)
> -# endif
> -        GLRO(dl_sysinfo) = new_sysinfo;
> -    }
> -#endif
> -
> -  __tunables_init (_environ);
> -
> -  /* Initialize DSO sorting algorithm after tunables.  */
> -  _dl_sort_maps_init ();
> -
> -#ifdef DL_SYSDEP_INIT
> -  DL_SYSDEP_INIT;
> -#endif
> -
> -#ifdef DL_PLATFORM_INIT
> -  DL_PLATFORM_INIT;
> -#endif
> -
> -  /* Determine the length of the platform name.  */
> -  if (GLRO(dl_platform) != NULL)
> -    GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
> -
> -  if (__sbrk (0) == _end)
> -    /* The dynamic linker was run as a program, and so the initial break
> -       starts just after our bss, at &_end.  The malloc in dl-minimal.c
> -       will consume the rest of this page, so tell the kernel to move the
> -       break up that far.  When the user program examines its break, it
> -       will see this new value and not clobber our data.  */
> -    __sbrk (GLRO(dl_pagesize)
> -	    - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1)));
> -
> -  /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
> -     allocated.  If necessary we are doing it ourself.  If it is not
> -     possible we stop the program.  */
> -  if (__builtin_expect (__libc_enable_secure, 0))
> -    __libc_check_standard_fds ();
> -
> -  (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
> -  return user_entry;
> -}
> -
> -void
> -_dl_sysdep_start_cleanup (void)
> -{
> -}
> -
> -void
> -_dl_show_auxv (void)
> -{
> -  char buf[64];
> -  ElfW(auxv_t) *av;
> -
> -  /* Terminate string.  */
> -  buf[63] = '\0';
> -
> -  /* The following code assumes that the AT_* values are encoded
> -     starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
> -     close by (otherwise the array will be too large).  In case we have
> -     to support a platform where these requirements are not fulfilled
> -     some alternative implementation has to be used.  */
> -  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av)
> -    {
> -      static const struct
> -      {
> -	const char label[22];
> -	enum { unknown = 0, dec, hex, str, ignore } form : 8;
> -      } auxvars[] =
> -	{
> -	  [AT_EXECFD - 2] =		{ "EXECFD:            ", dec },
> -	  [AT_EXECFN - 2] =		{ "EXECFN:            ", str },
> -	  [AT_PHDR - 2] =		{ "PHDR:              0x", hex },
> -	  [AT_PHENT - 2] =		{ "PHENT:             ", dec },
> -	  [AT_PHNUM - 2] =		{ "PHNUM:             ", dec },
> -	  [AT_PAGESZ - 2] =		{ "PAGESZ:            ", dec },
> -	  [AT_BASE - 2] =		{ "BASE:              0x", hex },
> -	  [AT_FLAGS - 2] =		{ "FLAGS:             0x", hex },
> -	  [AT_ENTRY - 2] =		{ "ENTRY:             0x", hex },
> -	  [AT_NOTELF - 2] =		{ "NOTELF:            ", hex },
> -	  [AT_UID - 2] =		{ "UID:               ", dec },
> -	  [AT_EUID - 2] =		{ "EUID:              ", dec },
> -	  [AT_GID - 2] =		{ "GID:               ", dec },
> -	  [AT_EGID - 2] =		{ "EGID:              ", dec },
> -	  [AT_PLATFORM - 2] =		{ "PLATFORM:          ", str },
> -	  [AT_HWCAP - 2] =		{ "HWCAP:             ", hex },
> -	  [AT_CLKTCK - 2] =		{ "CLKTCK:            ", dec },
> -	  [AT_FPUCW - 2] =		{ "FPUCW:             ", hex },
> -	  [AT_DCACHEBSIZE - 2] =	{ "DCACHEBSIZE:       0x", hex },
> -	  [AT_ICACHEBSIZE - 2] =	{ "ICACHEBSIZE:       0x", hex },
> -	  [AT_UCACHEBSIZE - 2] =	{ "UCACHEBSIZE:       0x", hex },
> -	  [AT_IGNOREPPC - 2] =		{ "IGNOREPPC", ignore },
> -	  [AT_SECURE - 2] =		{ "SECURE:            ", dec },
> -	  [AT_BASE_PLATFORM - 2] =	{ "BASE_PLATFORM:     ", str },
> -	  [AT_SYSINFO - 2] =		{ "SYSINFO:           0x", hex },
> -	  [AT_SYSINFO_EHDR - 2] =	{ "SYSINFO_EHDR:      0x", hex },
> -	  [AT_RANDOM - 2] =		{ "RANDOM:            0x", hex },
> -	  [AT_HWCAP2 - 2] =		{ "HWCAP2:            0x", hex },
> -	  [AT_MINSIGSTKSZ - 2] =	{ "MINSIGSTKSZ:       ", dec },
> -	  [AT_L1I_CACHESIZE - 2] =	{ "L1I_CACHESIZE:     ", dec },
> -	  [AT_L1I_CACHEGEOMETRY - 2] =	{ "L1I_CACHEGEOMETRY: 0x", hex },
> -	  [AT_L1D_CACHESIZE - 2] =	{ "L1D_CACHESIZE:     ", dec },
> -	  [AT_L1D_CACHEGEOMETRY - 2] =	{ "L1D_CACHEGEOMETRY: 0x", hex },
> -	  [AT_L2_CACHESIZE - 2] =	{ "L2_CACHESIZE:      ", dec },
> -	  [AT_L2_CACHEGEOMETRY - 2] =	{ "L2_CACHEGEOMETRY:  0x", hex },
> -	  [AT_L3_CACHESIZE - 2] =	{ "L3_CACHESIZE:      ", dec },
> -	  [AT_L3_CACHEGEOMETRY - 2] =	{ "L3_CACHEGEOMETRY:  0x", hex },
> -	};
> -      unsigned int idx = (unsigned int) (av->a_type - 2);
> -
> -      if ((unsigned int) av->a_type < 2u
> -	  || (idx < sizeof (auxvars) / sizeof (auxvars[0])
> -	      && auxvars[idx].form == ignore))
> -	continue;
> -
> -      assert (AT_NULL == 0);
> -      assert (AT_IGNORE == 1);
> -
> -      /* Some entries are handled in a special way per platform.  */
> -      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
> -	continue;
> -
> -      if (idx < sizeof (auxvars) / sizeof (auxvars[0])
> -	  && auxvars[idx].form != unknown)
> -	{
> -	  const char *val = (char *) av->a_un.a_val;
> -
> -	  if (__builtin_expect (auxvars[idx].form, dec) == dec)
> -	    val = _itoa ((unsigned long int) av->a_un.a_val,
> -			 buf + sizeof buf - 1, 10, 0);
> -	  else if (__builtin_expect (auxvars[idx].form, hex) == hex)
> -	    val = _itoa ((unsigned long int) av->a_un.a_val,
> -			 buf + sizeof buf - 1, 16, 0);
> -
> -	  _dl_printf ("AT_%s%s\n", auxvars[idx].label, val);
> -
> -	  continue;
> -	}
> -
> -      /* Unknown value: print a generic line.  */
> -      char buf2[17];
> -      buf2[sizeof (buf2) - 1] = '\0';
> -      const char *val2 = _itoa ((unsigned long int) av->a_un.a_val,
> -				buf2 + sizeof buf2 - 1, 16, 0);
> -      const char *val =  _itoa ((unsigned long int) av->a_type,
> -				buf + sizeof buf - 1, 16, 0);
> -      _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2);
> -    }
> -}
> -
> -#endif
> +#error dl-sysdep support missing.
> diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
> index 66ba489cd3..4f60cecf98 100644
> --- a/sysdeps/unix/sysv/linux/dl-sysdep.c
> +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c
> @@ -16,29 +16,352 @@
>     License along with the GNU C Library; if not, see
>     <https://www.gnu.org/licenses/>.  */
>  
> -/* Linux needs some special initialization, but otherwise uses
> -   the generic dynamic linker system interface code.  */
> -
> -#include <string.h>
> +#include <_itoa.h>
> +#include <assert.h>
> +#include <dl-auxv.h>
> +#include <dl-hwcap-check.h>
> +#include <dl-osinfo.h>
> +#include <dl-procinfo.h>
> +#include <dl-tunables.h>
> +#include <elf.h>
> +#include <entry.h>
> +#include <errno.h>
>  #include <fcntl.h>
> -#include <unistd.h>
> -#include <sys/param.h>
> -#include <sys/utsname.h>
> +#include <fpu_control.h>
>  #include <ldsodefs.h>
> +#include <libc-internal.h>
> +#include <libintl.h>
>  #include <not-cancel.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <sys/param.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <sys/utsname.h>
> +#include <tls.h>
> +#include <unistd.h>
> +
> +#include <dl-machine.h>
>  
>  #ifdef SHARED
> -# define DL_SYSDEP_INIT frob_brk ()
> +extern char **_environ attribute_hidden;
> +extern char _end[] attribute_hidden;
> +
> +/* Protect SUID program against misuse of file descriptors.  */
> +extern void __libc_check_standard_fds (void);
>  
> -static inline void
> -frob_brk (void)
> +int __libc_enable_secure attribute_relro = 0;
> +rtld_hidden_data_def (__libc_enable_secure)
> +/* This variable contains the lowest stack address ever used.  */
> +void *__libc_stack_end attribute_relro = NULL;
> +rtld_hidden_data_def(__libc_stack_end)
> +void *_dl_random attribute_relro = NULL;
> +
> +#ifndef DL_FIND_ARG_COMPONENTS
> +# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
> +  do {									      \
> +    void **_tmp;							      \
> +    (argc) = *(long int *) cookie;					      \
> +    (argv) = (char **) ((long int *) cookie + 1);			      \
> +    (envp) = (argv) + (argc) + 1;					      \
> +    for (_tmp = (void **) (envp); *_tmp; ++_tmp)			      \
> +      continue;								      \
> +    (auxp) = (void *) ++_tmp;						      \
> +  } while (0)
> +#endif
> +
> +#ifndef DL_STACK_END
> +# define DL_STACK_END(cookie) ((void *) (cookie))
> +#endif
> +
> +ElfW(Addr)
> +_dl_sysdep_start (void **start_argptr,
> +		  void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
> +				   ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
>  {
> +  const ElfW(Phdr) *phdr = NULL;
> +  ElfW(Word) phnum = 0;
> +  ElfW(Addr) user_entry;
> +  ElfW(auxv_t) *av;
> +#ifdef HAVE_AUX_SECURE
> +# define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
> +# define set_seen_secure() ((void) 0)
> +#else
> +  uid_t uid = 0;
> +  gid_t gid = 0;
> +  unsigned int seen = 0;
> +# define set_seen_secure() (seen = -1)
> +# ifdef HAVE_AUX_XID
> +#  define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
> +# else
> +#  define M(type) (1 << (type))
> +#  define set_seen(tag) seen |= M ((tag)->a_type)
> +# endif
> +#endif
> +#ifdef NEED_DL_SYSINFO
> +  uintptr_t new_sysinfo = 0;
> +#endif
> +
> +  __libc_stack_end = DL_STACK_END (start_argptr);
> +  DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ,
> +			  GLRO(dl_auxv));
> +
> +  user_entry = (ElfW(Addr)) ENTRY_POINT;
> +  GLRO(dl_platform) = NULL; /* Default to nothing known about the platform.  */
> +
> +  /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
> +  _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
> +		  "CONSTANT_MINSIGSTKSZ is constant");
> +  GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
> +
> +  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
> +    switch (av->a_type)
> +      {
> +      case AT_PHDR:
> +	phdr = (void *) av->a_un.a_val;
> +	break;
> +      case AT_PHNUM:
> +	phnum = av->a_un.a_val;
> +	break;
> +      case AT_PAGESZ:
> +	GLRO(dl_pagesize) = av->a_un.a_val;
> +	break;
> +      case AT_ENTRY:
> +	user_entry = av->a_un.a_val;
> +	break;
> +#ifndef HAVE_AUX_SECURE
> +      case AT_UID:
> +      case AT_EUID:
> +	uid ^= av->a_un.a_val;
> +	break;
> +      case AT_GID:
> +      case AT_EGID:
> +	gid ^= av->a_un.a_val;
> +	break;
> +#endif
> +      case AT_SECURE:
> +#ifndef HAVE_AUX_SECURE
> +	seen = -1;
> +#endif
> +	__libc_enable_secure = av->a_un.a_val;
> +	break;
> +      case AT_PLATFORM:
> +	GLRO(dl_platform) = (void *) av->a_un.a_val;
> +	break;
> +      case AT_HWCAP:
> +	GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
> +	break;
> +      case AT_HWCAP2:
> +	GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
> +	break;
> +      case AT_CLKTCK:
> +	GLRO(dl_clktck) = av->a_un.a_val;
> +	break;
> +      case AT_FPUCW:
> +	GLRO(dl_fpu_control) = av->a_un.a_val;
> +	break;
> +#ifdef NEED_DL_SYSINFO
> +      case AT_SYSINFO:
> +	new_sysinfo = av->a_un.a_val;
> +	break;
> +#endif
> +#ifdef NEED_DL_SYSINFO_DSO
> +      case AT_SYSINFO_EHDR:
> +	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
> +	break;
> +#endif
> +      case AT_RANDOM:
> +	_dl_random = (void *) av->a_un.a_val;
> +	break;
> +      case AT_MINSIGSTKSZ:
> +	GLRO(dl_minsigstacksize) = av->a_un.a_val;
> +	break;
> +      DL_PLATFORM_AUXV
> +      }
> +
> +  dl_hwcap_check ();
> +
> +#ifndef HAVE_AUX_SECURE
> +  if (seen != -1)
> +    {
> +      /* Fill in the values we have not gotten from the kernel through the
> +	 auxiliary vector.  */
> +# ifndef HAVE_AUX_XID
> +#  define SEE(UID, var, uid) \
> +   if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
> +      SEE (UID, uid, uid);
> +      SEE (EUID, uid, euid);
> +      SEE (GID, gid, gid);
> +      SEE (EGID, gid, egid);
> +# endif
> +
> +      /* If one of the two pairs of IDs does not match this is a setuid
> +	 or setgid run.  */
> +      __libc_enable_secure = uid | gid;
> +    }
> +#endif
> +
> +#ifndef HAVE_AUX_PAGESIZE
> +  if (GLRO(dl_pagesize) == 0)
> +    GLRO(dl_pagesize) = __getpagesize ();
> +#endif
> +
> +#ifdef NEED_DL_SYSINFO
> +  if (new_sysinfo != 0)
> +    {
> +# ifdef NEED_DL_SYSINFO_DSO
> +      /* Only set the sysinfo value if we also have the vsyscall DSO.  */
> +      if (GLRO(dl_sysinfo_dso) != 0)
> +# endif
> +        GLRO(dl_sysinfo) = new_sysinfo;
> +    }
> +#endif
> +
> +  __tunables_init (_environ);
> +
> +  /* Initialize DSO sorting algorithm after tunables.  */
> +  _dl_sort_maps_init ();
> +
>    __brk (0);			/* Initialize the break.  */
> -}
>  
> -# include <elf/dl-sysdep.c>
> +#ifdef DL_PLATFORM_INIT
> +  DL_PLATFORM_INIT;
>  #endif
>  
> +  /* Determine the length of the platform name.  */
> +  if (GLRO(dl_platform) != NULL)
> +    GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
> +
> +  if (__sbrk (0) == _end)
> +    /* The dynamic linker was run as a program, and so the initial break
> +       starts just after our bss, at &_end.  The malloc in dl-minimal.c
> +       will consume the rest of this page, so tell the kernel to move the
> +       break up that far.  When the user program examines its break, it
> +       will see this new value and not clobber our data.  */
> +    __sbrk (GLRO(dl_pagesize)
> +	    - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1)));
> +
> +  /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
> +     allocated.  If necessary we are doing it ourself.  If it is not
> +     possible we stop the program.  */
> +  if (__builtin_expect (__libc_enable_secure, 0))
> +    __libc_check_standard_fds ();
> +
> +  (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
> +  return user_entry;
> +}
> +
> +void
> +_dl_sysdep_start_cleanup (void)
> +{
> +}
> +
> +void
> +_dl_show_auxv (void)
> +{
> +  char buf[64];
> +  ElfW(auxv_t) *av;
> +
> +  /* Terminate string.  */
> +  buf[63] = '\0';
> +
> +  /* The following code assumes that the AT_* values are encoded
> +     starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
> +     close by (otherwise the array will be too large).  In case we have
> +     to support a platform where these requirements are not fulfilled
> +     some alternative implementation has to be used.  */
> +  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av)
> +    {
> +      static const struct
> +      {
> +	const char label[22];
> +	enum { unknown = 0, dec, hex, str, ignore } form : 8;
> +      } auxvars[] =
> +	{
> +	  [AT_EXECFD - 2] =		{ "EXECFD:            ", dec },
> +	  [AT_EXECFN - 2] =		{ "EXECFN:            ", str },
> +	  [AT_PHDR - 2] =		{ "PHDR:              0x", hex },
> +	  [AT_PHENT - 2] =		{ "PHENT:             ", dec },
> +	  [AT_PHNUM - 2] =		{ "PHNUM:             ", dec },
> +	  [AT_PAGESZ - 2] =		{ "PAGESZ:            ", dec },
> +	  [AT_BASE - 2] =		{ "BASE:              0x", hex },
> +	  [AT_FLAGS - 2] =		{ "FLAGS:             0x", hex },
> +	  [AT_ENTRY - 2] =		{ "ENTRY:             0x", hex },
> +	  [AT_NOTELF - 2] =		{ "NOTELF:            ", hex },
> +	  [AT_UID - 2] =		{ "UID:               ", dec },
> +	  [AT_EUID - 2] =		{ "EUID:              ", dec },
> +	  [AT_GID - 2] =		{ "GID:               ", dec },
> +	  [AT_EGID - 2] =		{ "EGID:              ", dec },
> +	  [AT_PLATFORM - 2] =		{ "PLATFORM:          ", str },
> +	  [AT_HWCAP - 2] =		{ "HWCAP:             ", hex },
> +	  [AT_CLKTCK - 2] =		{ "CLKTCK:            ", dec },
> +	  [AT_FPUCW - 2] =		{ "FPUCW:             ", hex },
> +	  [AT_DCACHEBSIZE - 2] =	{ "DCACHEBSIZE:       0x", hex },
> +	  [AT_ICACHEBSIZE - 2] =	{ "ICACHEBSIZE:       0x", hex },
> +	  [AT_UCACHEBSIZE - 2] =	{ "UCACHEBSIZE:       0x", hex },
> +	  [AT_IGNOREPPC - 2] =		{ "IGNOREPPC", ignore },
> +	  [AT_SECURE - 2] =		{ "SECURE:            ", dec },
> +	  [AT_BASE_PLATFORM - 2] =	{ "BASE_PLATFORM:     ", str },
> +	  [AT_SYSINFO - 2] =		{ "SYSINFO:           0x", hex },
> +	  [AT_SYSINFO_EHDR - 2] =	{ "SYSINFO_EHDR:      0x", hex },
> +	  [AT_RANDOM - 2] =		{ "RANDOM:            0x", hex },
> +	  [AT_HWCAP2 - 2] =		{ "HWCAP2:            0x", hex },
> +	  [AT_MINSIGSTKSZ - 2] =	{ "MINSIGSTKSZ:       ", dec },
> +	  [AT_L1I_CACHESIZE - 2] =	{ "L1I_CACHESIZE:     ", dec },
> +	  [AT_L1I_CACHEGEOMETRY - 2] =	{ "L1I_CACHEGEOMETRY: 0x", hex },
> +	  [AT_L1D_CACHESIZE - 2] =	{ "L1D_CACHESIZE:     ", dec },
> +	  [AT_L1D_CACHEGEOMETRY - 2] =	{ "L1D_CACHEGEOMETRY: 0x", hex },
> +	  [AT_L2_CACHESIZE - 2] =	{ "L2_CACHESIZE:      ", dec },
> +	  [AT_L2_CACHEGEOMETRY - 2] =	{ "L2_CACHEGEOMETRY:  0x", hex },
> +	  [AT_L3_CACHESIZE - 2] =	{ "L3_CACHESIZE:      ", dec },
> +	  [AT_L3_CACHEGEOMETRY - 2] =	{ "L3_CACHEGEOMETRY:  0x", hex },
> +	};
> +      unsigned int idx = (unsigned int) (av->a_type - 2);
> +
> +      if ((unsigned int) av->a_type < 2u
> +	  || (idx < sizeof (auxvars) / sizeof (auxvars[0])
> +	      && auxvars[idx].form == ignore))
> +	continue;
> +
> +      assert (AT_NULL == 0);
> +      assert (AT_IGNORE == 1);
> +
> +      /* Some entries are handled in a special way per platform.  */
> +      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
> +	continue;
> +
> +      if (idx < sizeof (auxvars) / sizeof (auxvars[0])
> +	  && auxvars[idx].form != unknown)
> +	{
> +	  const char *val = (char *) av->a_un.a_val;
> +
> +	  if (__builtin_expect (auxvars[idx].form, dec) == dec)
> +	    val = _itoa ((unsigned long int) av->a_un.a_val,
> +			 buf + sizeof buf - 1, 10, 0);
> +	  else if (__builtin_expect (auxvars[idx].form, hex) == hex)
> +	    val = _itoa ((unsigned long int) av->a_un.a_val,
> +			 buf + sizeof buf - 1, 16, 0);
> +
> +	  _dl_printf ("AT_%s%s\n", auxvars[idx].label, val);
> +
> +	  continue;
> +	}
> +
> +      /* Unknown value: print a generic line.  */
> +      char buf2[17];
> +      buf2[sizeof (buf2) - 1] = '\0';
> +      const char *val2 = _itoa ((unsigned long int) av->a_un.a_val,
> +				buf2 + sizeof buf2 - 1, 16, 0);
> +      const char *val =  _itoa ((unsigned long int) av->a_type,
> +				buf + sizeof buf - 1, 16, 0);
> +      _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2);
> +    }
> +}
> +
> +#endif /* SHARED */
> +
>  
>  int
>  attribute_hidden
  

Patch

diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
index f1dba8ef24..7aa90ad6ee 100644
--- a/elf/dl-sysdep.c
+++ b/elf/dl-sysdep.c
@@ -1,4 +1,4 @@ 
-/* Operating system support for run-time dynamic linker.  Generic Unix version.
+/* Operating system support for run-time dynamic linker.  Stub version.
    Copyright (C) 1995-2022 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -16,352 +16,4 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-/* We conditionalize the whole of this file rather than simply eliding it
-   from the static build, because other sysdeps/ versions of this file
-   might define things needed by a static build.  */
-
-#ifdef SHARED
-
-#include <assert.h>
-#include <elf.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <libintl.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <ldsodefs.h>
-#include <_itoa.h>
-#include <fpu_control.h>
-
-#include <entry.h>
-#include <dl-machine.h>
-#include <dl-procinfo.h>
-#include <dl-osinfo.h>
-#include <libc-internal.h>
-#include <tls.h>
-
-#include <dl-tunables.h>
-#include <dl-auxv.h>
-#include <dl-hwcap-check.h>
-
-extern char **_environ attribute_hidden;
-extern char _end[] attribute_hidden;
-
-/* Protect SUID program against misuse of file descriptors.  */
-extern void __libc_check_standard_fds (void);
-
-int __libc_enable_secure attribute_relro = 0;
-rtld_hidden_data_def (__libc_enable_secure)
-/* This variable contains the lowest stack address ever used.  */
-void *__libc_stack_end attribute_relro = NULL;
-rtld_hidden_data_def(__libc_stack_end)
-void *_dl_random attribute_relro = NULL;
-
-#ifndef DL_FIND_ARG_COMPONENTS
-# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
-  do {									      \
-    void **_tmp;							      \
-    (argc) = *(long int *) cookie;					      \
-    (argv) = (char **) ((long int *) cookie + 1);			      \
-    (envp) = (argv) + (argc) + 1;					      \
-    for (_tmp = (void **) (envp); *_tmp; ++_tmp)			      \
-      continue;								      \
-    (auxp) = (void *) ++_tmp;						      \
-  } while (0)
-#endif
-
-#ifndef DL_STACK_END
-# define DL_STACK_END(cookie) ((void *) (cookie))
-#endif
-
-ElfW(Addr)
-_dl_sysdep_start (void **start_argptr,
-		  void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
-				   ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
-{
-  const ElfW(Phdr) *phdr = NULL;
-  ElfW(Word) phnum = 0;
-  ElfW(Addr) user_entry;
-  ElfW(auxv_t) *av;
-#ifdef HAVE_AUX_SECURE
-# define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
-# define set_seen_secure() ((void) 0)
-#else
-  uid_t uid = 0;
-  gid_t gid = 0;
-  unsigned int seen = 0;
-# define set_seen_secure() (seen = -1)
-# ifdef HAVE_AUX_XID
-#  define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
-# else
-#  define M(type) (1 << (type))
-#  define set_seen(tag) seen |= M ((tag)->a_type)
-# endif
-#endif
-#ifdef NEED_DL_SYSINFO
-  uintptr_t new_sysinfo = 0;
-#endif
-
-  __libc_stack_end = DL_STACK_END (start_argptr);
-  DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ,
-			  GLRO(dl_auxv));
-
-  user_entry = (ElfW(Addr)) ENTRY_POINT;
-  GLRO(dl_platform) = NULL; /* Default to nothing known about the platform.  */
-
-  /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
-  _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
-		  "CONSTANT_MINSIGSTKSZ is constant");
-  GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
-
-  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
-    switch (av->a_type)
-      {
-      case AT_PHDR:
-	phdr = (void *) av->a_un.a_val;
-	break;
-      case AT_PHNUM:
-	phnum = av->a_un.a_val;
-	break;
-      case AT_PAGESZ:
-	GLRO(dl_pagesize) = av->a_un.a_val;
-	break;
-      case AT_ENTRY:
-	user_entry = av->a_un.a_val;
-	break;
-#ifndef HAVE_AUX_SECURE
-      case AT_UID:
-      case AT_EUID:
-	uid ^= av->a_un.a_val;
-	break;
-      case AT_GID:
-      case AT_EGID:
-	gid ^= av->a_un.a_val;
-	break;
-#endif
-      case AT_SECURE:
-#ifndef HAVE_AUX_SECURE
-	seen = -1;
-#endif
-	__libc_enable_secure = av->a_un.a_val;
-	break;
-      case AT_PLATFORM:
-	GLRO(dl_platform) = (void *) av->a_un.a_val;
-	break;
-      case AT_HWCAP:
-	GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
-	break;
-      case AT_HWCAP2:
-	GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
-	break;
-      case AT_CLKTCK:
-	GLRO(dl_clktck) = av->a_un.a_val;
-	break;
-      case AT_FPUCW:
-	GLRO(dl_fpu_control) = av->a_un.a_val;
-	break;
-#ifdef NEED_DL_SYSINFO
-      case AT_SYSINFO:
-	new_sysinfo = av->a_un.a_val;
-	break;
-#endif
-#ifdef NEED_DL_SYSINFO_DSO
-      case AT_SYSINFO_EHDR:
-	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
-	break;
-#endif
-      case AT_RANDOM:
-	_dl_random = (void *) av->a_un.a_val;
-	break;
-      case AT_MINSIGSTKSZ:
-	GLRO(dl_minsigstacksize) = av->a_un.a_val;
-	break;
-      DL_PLATFORM_AUXV
-      }
-
-  dl_hwcap_check ();
-
-#ifndef HAVE_AUX_SECURE
-  if (seen != -1)
-    {
-      /* Fill in the values we have not gotten from the kernel through the
-	 auxiliary vector.  */
-# ifndef HAVE_AUX_XID
-#  define SEE(UID, var, uid) \
-   if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
-      SEE (UID, uid, uid);
-      SEE (EUID, uid, euid);
-      SEE (GID, gid, gid);
-      SEE (EGID, gid, egid);
-# endif
-
-      /* If one of the two pairs of IDs does not match this is a setuid
-	 or setgid run.  */
-      __libc_enable_secure = uid | gid;
-    }
-#endif
-
-#ifndef HAVE_AUX_PAGESIZE
-  if (GLRO(dl_pagesize) == 0)
-    GLRO(dl_pagesize) = __getpagesize ();
-#endif
-
-#ifdef NEED_DL_SYSINFO
-  if (new_sysinfo != 0)
-    {
-# ifdef NEED_DL_SYSINFO_DSO
-      /* Only set the sysinfo value if we also have the vsyscall DSO.  */
-      if (GLRO(dl_sysinfo_dso) != 0)
-# endif
-        GLRO(dl_sysinfo) = new_sysinfo;
-    }
-#endif
-
-  __tunables_init (_environ);
-
-  /* Initialize DSO sorting algorithm after tunables.  */
-  _dl_sort_maps_init ();
-
-#ifdef DL_SYSDEP_INIT
-  DL_SYSDEP_INIT;
-#endif
-
-#ifdef DL_PLATFORM_INIT
-  DL_PLATFORM_INIT;
-#endif
-
-  /* Determine the length of the platform name.  */
-  if (GLRO(dl_platform) != NULL)
-    GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
-
-  if (__sbrk (0) == _end)
-    /* The dynamic linker was run as a program, and so the initial break
-       starts just after our bss, at &_end.  The malloc in dl-minimal.c
-       will consume the rest of this page, so tell the kernel to move the
-       break up that far.  When the user program examines its break, it
-       will see this new value and not clobber our data.  */
-    __sbrk (GLRO(dl_pagesize)
-	    - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1)));
-
-  /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
-     allocated.  If necessary we are doing it ourself.  If it is not
-     possible we stop the program.  */
-  if (__builtin_expect (__libc_enable_secure, 0))
-    __libc_check_standard_fds ();
-
-  (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
-  return user_entry;
-}
-
-void
-_dl_sysdep_start_cleanup (void)
-{
-}
-
-void
-_dl_show_auxv (void)
-{
-  char buf[64];
-  ElfW(auxv_t) *av;
-
-  /* Terminate string.  */
-  buf[63] = '\0';
-
-  /* The following code assumes that the AT_* values are encoded
-     starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
-     close by (otherwise the array will be too large).  In case we have
-     to support a platform where these requirements are not fulfilled
-     some alternative implementation has to be used.  */
-  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av)
-    {
-      static const struct
-      {
-	const char label[22];
-	enum { unknown = 0, dec, hex, str, ignore } form : 8;
-      } auxvars[] =
-	{
-	  [AT_EXECFD - 2] =		{ "EXECFD:            ", dec },
-	  [AT_EXECFN - 2] =		{ "EXECFN:            ", str },
-	  [AT_PHDR - 2] =		{ "PHDR:              0x", hex },
-	  [AT_PHENT - 2] =		{ "PHENT:             ", dec },
-	  [AT_PHNUM - 2] =		{ "PHNUM:             ", dec },
-	  [AT_PAGESZ - 2] =		{ "PAGESZ:            ", dec },
-	  [AT_BASE - 2] =		{ "BASE:              0x", hex },
-	  [AT_FLAGS - 2] =		{ "FLAGS:             0x", hex },
-	  [AT_ENTRY - 2] =		{ "ENTRY:             0x", hex },
-	  [AT_NOTELF - 2] =		{ "NOTELF:            ", hex },
-	  [AT_UID - 2] =		{ "UID:               ", dec },
-	  [AT_EUID - 2] =		{ "EUID:              ", dec },
-	  [AT_GID - 2] =		{ "GID:               ", dec },
-	  [AT_EGID - 2] =		{ "EGID:              ", dec },
-	  [AT_PLATFORM - 2] =		{ "PLATFORM:          ", str },
-	  [AT_HWCAP - 2] =		{ "HWCAP:             ", hex },
-	  [AT_CLKTCK - 2] =		{ "CLKTCK:            ", dec },
-	  [AT_FPUCW - 2] =		{ "FPUCW:             ", hex },
-	  [AT_DCACHEBSIZE - 2] =	{ "DCACHEBSIZE:       0x", hex },
-	  [AT_ICACHEBSIZE - 2] =	{ "ICACHEBSIZE:       0x", hex },
-	  [AT_UCACHEBSIZE - 2] =	{ "UCACHEBSIZE:       0x", hex },
-	  [AT_IGNOREPPC - 2] =		{ "IGNOREPPC", ignore },
-	  [AT_SECURE - 2] =		{ "SECURE:            ", dec },
-	  [AT_BASE_PLATFORM - 2] =	{ "BASE_PLATFORM:     ", str },
-	  [AT_SYSINFO - 2] =		{ "SYSINFO:           0x", hex },
-	  [AT_SYSINFO_EHDR - 2] =	{ "SYSINFO_EHDR:      0x", hex },
-	  [AT_RANDOM - 2] =		{ "RANDOM:            0x", hex },
-	  [AT_HWCAP2 - 2] =		{ "HWCAP2:            0x", hex },
-	  [AT_MINSIGSTKSZ - 2] =	{ "MINSIGSTKSZ:       ", dec },
-	  [AT_L1I_CACHESIZE - 2] =	{ "L1I_CACHESIZE:     ", dec },
-	  [AT_L1I_CACHEGEOMETRY - 2] =	{ "L1I_CACHEGEOMETRY: 0x", hex },
-	  [AT_L1D_CACHESIZE - 2] =	{ "L1D_CACHESIZE:     ", dec },
-	  [AT_L1D_CACHEGEOMETRY - 2] =	{ "L1D_CACHEGEOMETRY: 0x", hex },
-	  [AT_L2_CACHESIZE - 2] =	{ "L2_CACHESIZE:      ", dec },
-	  [AT_L2_CACHEGEOMETRY - 2] =	{ "L2_CACHEGEOMETRY:  0x", hex },
-	  [AT_L3_CACHESIZE - 2] =	{ "L3_CACHESIZE:      ", dec },
-	  [AT_L3_CACHEGEOMETRY - 2] =	{ "L3_CACHEGEOMETRY:  0x", hex },
-	};
-      unsigned int idx = (unsigned int) (av->a_type - 2);
-
-      if ((unsigned int) av->a_type < 2u
-	  || (idx < sizeof (auxvars) / sizeof (auxvars[0])
-	      && auxvars[idx].form == ignore))
-	continue;
-
-      assert (AT_NULL == 0);
-      assert (AT_IGNORE == 1);
-
-      /* Some entries are handled in a special way per platform.  */
-      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
-	continue;
-
-      if (idx < sizeof (auxvars) / sizeof (auxvars[0])
-	  && auxvars[idx].form != unknown)
-	{
-	  const char *val = (char *) av->a_un.a_val;
-
-	  if (__builtin_expect (auxvars[idx].form, dec) == dec)
-	    val = _itoa ((unsigned long int) av->a_un.a_val,
-			 buf + sizeof buf - 1, 10, 0);
-	  else if (__builtin_expect (auxvars[idx].form, hex) == hex)
-	    val = _itoa ((unsigned long int) av->a_un.a_val,
-			 buf + sizeof buf - 1, 16, 0);
-
-	  _dl_printf ("AT_%s%s\n", auxvars[idx].label, val);
-
-	  continue;
-	}
-
-      /* Unknown value: print a generic line.  */
-      char buf2[17];
-      buf2[sizeof (buf2) - 1] = '\0';
-      const char *val2 = _itoa ((unsigned long int) av->a_un.a_val,
-				buf2 + sizeof buf2 - 1, 16, 0);
-      const char *val =  _itoa ((unsigned long int) av->a_type,
-				buf + sizeof buf - 1, 16, 0);
-      _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2);
-    }
-}
-
-#endif
+#error dl-sysdep support missing.
diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
index 66ba489cd3..4f60cecf98 100644
--- a/sysdeps/unix/sysv/linux/dl-sysdep.c
+++ b/sysdeps/unix/sysv/linux/dl-sysdep.c
@@ -16,29 +16,352 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-/* Linux needs some special initialization, but otherwise uses
-   the generic dynamic linker system interface code.  */
-
-#include <string.h>
+#include <_itoa.h>
+#include <assert.h>
+#include <dl-auxv.h>
+#include <dl-hwcap-check.h>
+#include <dl-osinfo.h>
+#include <dl-procinfo.h>
+#include <dl-tunables.h>
+#include <elf.h>
+#include <entry.h>
+#include <errno.h>
 #include <fcntl.h>
-#include <unistd.h>
-#include <sys/param.h>
-#include <sys/utsname.h>
+#include <fpu_control.h>
 #include <ldsodefs.h>
+#include <libc-internal.h>
+#include <libintl.h>
 #include <not-cancel.h>
+#include <stdlib.h>
+#include <string.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/utsname.h>
+#include <tls.h>
+#include <unistd.h>
+
+#include <dl-machine.h>
 
 #ifdef SHARED
-# define DL_SYSDEP_INIT frob_brk ()
+extern char **_environ attribute_hidden;
+extern char _end[] attribute_hidden;
+
+/* Protect SUID program against misuse of file descriptors.  */
+extern void __libc_check_standard_fds (void);
 
-static inline void
-frob_brk (void)
+int __libc_enable_secure attribute_relro = 0;
+rtld_hidden_data_def (__libc_enable_secure)
+/* This variable contains the lowest stack address ever used.  */
+void *__libc_stack_end attribute_relro = NULL;
+rtld_hidden_data_def(__libc_stack_end)
+void *_dl_random attribute_relro = NULL;
+
+#ifndef DL_FIND_ARG_COMPONENTS
+# define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp)	\
+  do {									      \
+    void **_tmp;							      \
+    (argc) = *(long int *) cookie;					      \
+    (argv) = (char **) ((long int *) cookie + 1);			      \
+    (envp) = (argv) + (argc) + 1;					      \
+    for (_tmp = (void **) (envp); *_tmp; ++_tmp)			      \
+      continue;								      \
+    (auxp) = (void *) ++_tmp;						      \
+  } while (0)
+#endif
+
+#ifndef DL_STACK_END
+# define DL_STACK_END(cookie) ((void *) (cookie))
+#endif
+
+ElfW(Addr)
+_dl_sysdep_start (void **start_argptr,
+		  void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum,
+				   ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv))
 {
+  const ElfW(Phdr) *phdr = NULL;
+  ElfW(Word) phnum = 0;
+  ElfW(Addr) user_entry;
+  ElfW(auxv_t) *av;
+#ifdef HAVE_AUX_SECURE
+# define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
+# define set_seen_secure() ((void) 0)
+#else
+  uid_t uid = 0;
+  gid_t gid = 0;
+  unsigned int seen = 0;
+# define set_seen_secure() (seen = -1)
+# ifdef HAVE_AUX_XID
+#  define set_seen(tag) (tag)	/* Evaluate for the side effects.  */
+# else
+#  define M(type) (1 << (type))
+#  define set_seen(tag) seen |= M ((tag)->a_type)
+# endif
+#endif
+#ifdef NEED_DL_SYSINFO
+  uintptr_t new_sysinfo = 0;
+#endif
+
+  __libc_stack_end = DL_STACK_END (start_argptr);
+  DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, _dl_argv, _environ,
+			  GLRO(dl_auxv));
+
+  user_entry = (ElfW(Addr)) ENTRY_POINT;
+  GLRO(dl_platform) = NULL; /* Default to nothing known about the platform.  */
+
+  /* NB: Default to a constant CONSTANT_MINSIGSTKSZ.  */
+  _Static_assert (__builtin_constant_p (CONSTANT_MINSIGSTKSZ),
+		  "CONSTANT_MINSIGSTKSZ is constant");
+  GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
+
+  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
+    switch (av->a_type)
+      {
+      case AT_PHDR:
+	phdr = (void *) av->a_un.a_val;
+	break;
+      case AT_PHNUM:
+	phnum = av->a_un.a_val;
+	break;
+      case AT_PAGESZ:
+	GLRO(dl_pagesize) = av->a_un.a_val;
+	break;
+      case AT_ENTRY:
+	user_entry = av->a_un.a_val;
+	break;
+#ifndef HAVE_AUX_SECURE
+      case AT_UID:
+      case AT_EUID:
+	uid ^= av->a_un.a_val;
+	break;
+      case AT_GID:
+      case AT_EGID:
+	gid ^= av->a_un.a_val;
+	break;
+#endif
+      case AT_SECURE:
+#ifndef HAVE_AUX_SECURE
+	seen = -1;
+#endif
+	__libc_enable_secure = av->a_un.a_val;
+	break;
+      case AT_PLATFORM:
+	GLRO(dl_platform) = (void *) av->a_un.a_val;
+	break;
+      case AT_HWCAP:
+	GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val;
+	break;
+      case AT_HWCAP2:
+	GLRO(dl_hwcap2) = (unsigned long int) av->a_un.a_val;
+	break;
+      case AT_CLKTCK:
+	GLRO(dl_clktck) = av->a_un.a_val;
+	break;
+      case AT_FPUCW:
+	GLRO(dl_fpu_control) = av->a_un.a_val;
+	break;
+#ifdef NEED_DL_SYSINFO
+      case AT_SYSINFO:
+	new_sysinfo = av->a_un.a_val;
+	break;
+#endif
+#ifdef NEED_DL_SYSINFO_DSO
+      case AT_SYSINFO_EHDR:
+	GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val;
+	break;
+#endif
+      case AT_RANDOM:
+	_dl_random = (void *) av->a_un.a_val;
+	break;
+      case AT_MINSIGSTKSZ:
+	GLRO(dl_minsigstacksize) = av->a_un.a_val;
+	break;
+      DL_PLATFORM_AUXV
+      }
+
+  dl_hwcap_check ();
+
+#ifndef HAVE_AUX_SECURE
+  if (seen != -1)
+    {
+      /* Fill in the values we have not gotten from the kernel through the
+	 auxiliary vector.  */
+# ifndef HAVE_AUX_XID
+#  define SEE(UID, var, uid) \
+   if ((seen & M (AT_##UID)) == 0) var ^= __get##uid ()
+      SEE (UID, uid, uid);
+      SEE (EUID, uid, euid);
+      SEE (GID, gid, gid);
+      SEE (EGID, gid, egid);
+# endif
+
+      /* If one of the two pairs of IDs does not match this is a setuid
+	 or setgid run.  */
+      __libc_enable_secure = uid | gid;
+    }
+#endif
+
+#ifndef HAVE_AUX_PAGESIZE
+  if (GLRO(dl_pagesize) == 0)
+    GLRO(dl_pagesize) = __getpagesize ();
+#endif
+
+#ifdef NEED_DL_SYSINFO
+  if (new_sysinfo != 0)
+    {
+# ifdef NEED_DL_SYSINFO_DSO
+      /* Only set the sysinfo value if we also have the vsyscall DSO.  */
+      if (GLRO(dl_sysinfo_dso) != 0)
+# endif
+        GLRO(dl_sysinfo) = new_sysinfo;
+    }
+#endif
+
+  __tunables_init (_environ);
+
+  /* Initialize DSO sorting algorithm after tunables.  */
+  _dl_sort_maps_init ();
+
   __brk (0);			/* Initialize the break.  */
-}
 
-# include <elf/dl-sysdep.c>
+#ifdef DL_PLATFORM_INIT
+  DL_PLATFORM_INIT;
 #endif
 
+  /* Determine the length of the platform name.  */
+  if (GLRO(dl_platform) != NULL)
+    GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
+
+  if (__sbrk (0) == _end)
+    /* The dynamic linker was run as a program, and so the initial break
+       starts just after our bss, at &_end.  The malloc in dl-minimal.c
+       will consume the rest of this page, so tell the kernel to move the
+       break up that far.  When the user program examines its break, it
+       will see this new value and not clobber our data.  */
+    __sbrk (GLRO(dl_pagesize)
+	    - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1)));
+
+  /* If this is a SUID program we make sure that FDs 0, 1, and 2 are
+     allocated.  If necessary we are doing it ourself.  If it is not
+     possible we stop the program.  */
+  if (__builtin_expect (__libc_enable_secure, 0))
+    __libc_check_standard_fds ();
+
+  (*dl_main) (phdr, phnum, &user_entry, GLRO(dl_auxv));
+  return user_entry;
+}
+
+void
+_dl_sysdep_start_cleanup (void)
+{
+}
+
+void
+_dl_show_auxv (void)
+{
+  char buf[64];
+  ElfW(auxv_t) *av;
+
+  /* Terminate string.  */
+  buf[63] = '\0';
+
+  /* The following code assumes that the AT_* values are encoded
+     starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values
+     close by (otherwise the array will be too large).  In case we have
+     to support a platform where these requirements are not fulfilled
+     some alternative implementation has to be used.  */
+  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; ++av)
+    {
+      static const struct
+      {
+	const char label[22];
+	enum { unknown = 0, dec, hex, str, ignore } form : 8;
+      } auxvars[] =
+	{
+	  [AT_EXECFD - 2] =		{ "EXECFD:            ", dec },
+	  [AT_EXECFN - 2] =		{ "EXECFN:            ", str },
+	  [AT_PHDR - 2] =		{ "PHDR:              0x", hex },
+	  [AT_PHENT - 2] =		{ "PHENT:             ", dec },
+	  [AT_PHNUM - 2] =		{ "PHNUM:             ", dec },
+	  [AT_PAGESZ - 2] =		{ "PAGESZ:            ", dec },
+	  [AT_BASE - 2] =		{ "BASE:              0x", hex },
+	  [AT_FLAGS - 2] =		{ "FLAGS:             0x", hex },
+	  [AT_ENTRY - 2] =		{ "ENTRY:             0x", hex },
+	  [AT_NOTELF - 2] =		{ "NOTELF:            ", hex },
+	  [AT_UID - 2] =		{ "UID:               ", dec },
+	  [AT_EUID - 2] =		{ "EUID:              ", dec },
+	  [AT_GID - 2] =		{ "GID:               ", dec },
+	  [AT_EGID - 2] =		{ "EGID:              ", dec },
+	  [AT_PLATFORM - 2] =		{ "PLATFORM:          ", str },
+	  [AT_HWCAP - 2] =		{ "HWCAP:             ", hex },
+	  [AT_CLKTCK - 2] =		{ "CLKTCK:            ", dec },
+	  [AT_FPUCW - 2] =		{ "FPUCW:             ", hex },
+	  [AT_DCACHEBSIZE - 2] =	{ "DCACHEBSIZE:       0x", hex },
+	  [AT_ICACHEBSIZE - 2] =	{ "ICACHEBSIZE:       0x", hex },
+	  [AT_UCACHEBSIZE - 2] =	{ "UCACHEBSIZE:       0x", hex },
+	  [AT_IGNOREPPC - 2] =		{ "IGNOREPPC", ignore },
+	  [AT_SECURE - 2] =		{ "SECURE:            ", dec },
+	  [AT_BASE_PLATFORM - 2] =	{ "BASE_PLATFORM:     ", str },
+	  [AT_SYSINFO - 2] =		{ "SYSINFO:           0x", hex },
+	  [AT_SYSINFO_EHDR - 2] =	{ "SYSINFO_EHDR:      0x", hex },
+	  [AT_RANDOM - 2] =		{ "RANDOM:            0x", hex },
+	  [AT_HWCAP2 - 2] =		{ "HWCAP2:            0x", hex },
+	  [AT_MINSIGSTKSZ - 2] =	{ "MINSIGSTKSZ:       ", dec },
+	  [AT_L1I_CACHESIZE - 2] =	{ "L1I_CACHESIZE:     ", dec },
+	  [AT_L1I_CACHEGEOMETRY - 2] =	{ "L1I_CACHEGEOMETRY: 0x", hex },
+	  [AT_L1D_CACHESIZE - 2] =	{ "L1D_CACHESIZE:     ", dec },
+	  [AT_L1D_CACHEGEOMETRY - 2] =	{ "L1D_CACHEGEOMETRY: 0x", hex },
+	  [AT_L2_CACHESIZE - 2] =	{ "L2_CACHESIZE:      ", dec },
+	  [AT_L2_CACHEGEOMETRY - 2] =	{ "L2_CACHEGEOMETRY:  0x", hex },
+	  [AT_L3_CACHESIZE - 2] =	{ "L3_CACHESIZE:      ", dec },
+	  [AT_L3_CACHEGEOMETRY - 2] =	{ "L3_CACHEGEOMETRY:  0x", hex },
+	};
+      unsigned int idx = (unsigned int) (av->a_type - 2);
+
+      if ((unsigned int) av->a_type < 2u
+	  || (idx < sizeof (auxvars) / sizeof (auxvars[0])
+	      && auxvars[idx].form == ignore))
+	continue;
+
+      assert (AT_NULL == 0);
+      assert (AT_IGNORE == 1);
+
+      /* Some entries are handled in a special way per platform.  */
+      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
+	continue;
+
+      if (idx < sizeof (auxvars) / sizeof (auxvars[0])
+	  && auxvars[idx].form != unknown)
+	{
+	  const char *val = (char *) av->a_un.a_val;
+
+	  if (__builtin_expect (auxvars[idx].form, dec) == dec)
+	    val = _itoa ((unsigned long int) av->a_un.a_val,
+			 buf + sizeof buf - 1, 10, 0);
+	  else if (__builtin_expect (auxvars[idx].form, hex) == hex)
+	    val = _itoa ((unsigned long int) av->a_un.a_val,
+			 buf + sizeof buf - 1, 16, 0);
+
+	  _dl_printf ("AT_%s%s\n", auxvars[idx].label, val);
+
+	  continue;
+	}
+
+      /* Unknown value: print a generic line.  */
+      char buf2[17];
+      buf2[sizeof (buf2) - 1] = '\0';
+      const char *val2 = _itoa ((unsigned long int) av->a_un.a_val,
+				buf2 + sizeof buf2 - 1, 16, 0);
+      const char *val =  _itoa ((unsigned long int) av->a_type,
+				buf + sizeof buf - 1, 16, 0);
+      _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2);
+    }
+}
+
+#endif /* SHARED */
+
 
 int
 attribute_hidden