Re: [PATCH v2 2/5] Linux: Remove HAVE_AUX_SECURE, HAVE_AUX_XID, HAVE_AUX_PAGESIZE

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 03/02/2022 08:08, Florian Weimer via Libc-alpha wrote:
> They are always defined.

LGTM, thanks.

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

> ---
>  sysdeps/unix/sysv/linux/dl-sysdep.c | 55 +----------------------------
>  sysdeps/unix/sysv/linux/ldsodefs.h  | 12 -------
>  2 files changed, 1 insertion(+), 66 deletions(-)
> 
> diff --git a/sysdeps/unix/sysv/linux/dl-sysdep.c b/sysdeps/unix/sysv/linux/dl-sysdep.c
> index 4f60cecf98..72aa109f2f 100644
> --- a/sysdeps/unix/sysv/linux/dl-sysdep.c
> +++ b/sysdeps/unix/sysv/linux/dl-sysdep.c
> @@ -85,21 +85,6 @@ _dl_sysdep_start (void **start_argptr,
>    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
> @@ -116,7 +101,7 @@ _dl_sysdep_start (void **start_argptr,
>  		  "CONSTANT_MINSIGSTKSZ is constant");
>    GLRO(dl_minsigstacksize) = CONSTANT_MINSIGSTKSZ;
>  
> -  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; set_seen (av++))
> +  for (av = GLRO(dl_auxv); av->a_type != AT_NULL; av++)
>      switch (av->a_type)
>        {
>        case AT_PHDR:
> @@ -131,20 +116,7 @@ _dl_sysdep_start (void **start_argptr,
>        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:
> @@ -183,31 +155,6 @@ _dl_sysdep_start (void **start_argptr,
>  
>    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)
>      {
> diff --git a/sysdeps/unix/sysv/linux/ldsodefs.h b/sysdeps/unix/sysv/linux/ldsodefs.h
> index 011756ddc1..af108991f0 100644
> --- a/sysdeps/unix/sysv/linux/ldsodefs.h
> +++ b/sysdeps/unix/sysv/linux/ldsodefs.h
> @@ -24,16 +24,4 @@
>  /* Get the real definitions.  */
>  #include_next <ldsodefs.h>
>  
> -/* We can assume that the kernel always provides the AT_UID, AT_EUID,
> -   AT_GID, and AT_EGID values in the auxiliary vector from 2.4.0 or so on.  */
> -#define HAVE_AUX_XID
> -
> -/* We can assume that the kernel always provides the AT_SECURE value
> -   in the auxiliary vector from 2.5.74 or so on.  */
> -#define HAVE_AUX_SECURE
> -
> -/* Starting with one of the 2.4.0 pre-releases the Linux kernel passes
> -   up the page size information.  */
> -#define HAVE_AUX_PAGESIZE
> -
>  #endif /* ldsodefs.h */