/* Initialization code for TLS in statically linked application.

   Copyright (C) 2002-2018 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 <startup.h>

#include <errno.h>

#include <ldsodefs.h>

#include <tls.h>

#include <unistd.h>

#include <stdio.h>

#include <sys/param.h>

#ifdef SHARED

 #error makefile bug, this file is for static only

#endif

dtv_t _dl_static_dtv[2 + TLS_SLOTINFO_SURPLUS];

static struct

{

  struct dtv_slotinfo_list si;

  /* The dtv_slotinfo_list data structure does not include the actual

     information since it is defined as an array of size zero.  We define

     here the necessary entries.  Note that it is not important whether

     there is padding or not since we will always access the information

     through the 'si' element.  */

  struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];

} static_slotinfo;

/* Highest dtv index currently needed.  */

size_t _dl_tls_max_dtv_idx;

/* Flag signalling whether there are gaps in the module ID allocation.  */

bool _dl_tls_dtv_gaps;

/* Information about the dtv slots.  */

struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;

/* Number of modules in the static TLS block.  */

size_t _dl_tls_static_nelem;

/* Size of the static TLS block.  Giving this initialized value

   preallocates some surplus bytes in the static TLS area.  */

size_t _dl_tls_static_size = 2048;

/* Size actually allocated in the static TLS block.  */

size_t _dl_tls_static_used;

/* Alignment requirement of the static TLS block.  */

size_t _dl_tls_static_align;

/* Generation counter for the dtv.  */

size_t _dl_tls_generation;

/* Additional definitions needed by TLS initialization.  */

#ifdef TLS_INIT_HELPER

TLS_INIT_HELPER

#endif

static void

init_slotinfo (void)

{

  /* Create the slotinfo list.  */

  static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)

			     - (char *) &static_slotinfo.si.slotinfo[0])

			    / sizeof static_slotinfo.si.slotinfo[0]);

  // static_slotinfo.si.next = NULL;	already zero

  /* The slotinfo list.  Will be extended by the code doing dynamic

     linking.  */

  GL(dl_tls_max_dtv_idx) = 1;

  GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;

}

static void

init_static_tls (size_t memsz, size_t align)

{

  /* That is the size of the TLS memory for this object.  The initialized

     value of _dl_tls_static_size is provided by dl-open.c to request some

     surplus that permits dynamic loading of modules with IE-model TLS.  */

  GL(dl_tls_static_size) = roundup (memsz + GL(dl_tls_static_size),

				    TLS_TCB_ALIGN);

#if TLS_TCB_AT_TP

  GL(dl_tls_static_size) += TLS_TCB_SIZE;

#endif

  GL(dl_tls_static_used) = memsz;

  /* The alignment requirement for the static TLS block.  */

  GL(dl_tls_static_align) = align;

  /* Number of elements in the static TLS block.  */

  GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);

}

void

__libc_setup_tls (void)

{

  void *tlsblock;

  size_t memsz = 0;

  size_t filesz = 0;

  void *initimage = NULL;

  size_t align = 0;

  size_t max_align = TCB_ALIGNMENT;

  size_t tcb_offset;

  const ElfW(Phdr) *phdr;

  struct link_map *main_map = GL(dl_ns)[LM_ID_BASE]._ns_loaded;

  /* Look through the TLS segment if there is any.  */

  if (_dl_phdr != NULL)

    for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)

      if (phdr->p_type == PT_TLS)

	{

	  /* Remember the values we need.  */

	  memsz = phdr->p_memsz;

	  filesz = phdr->p_filesz;

	  initimage = (void *) phdr->p_vaddr + main_map->l_addr;

	  align = phdr->p_align;

	  if (phdr->p_align > max_align)

	    max_align = phdr->p_align;

	  break;

	}

  /* We have to set up the TCB block which also (possibly) contains

     'errno'.  Therefore we avoid 'malloc' which might touch 'errno'.

     Instead we use 'sbrk' which would only uses 'errno' if it fails.

     In this case we are right away out of memory and the user gets

     what she/he deserves.

     The initialized value of _dl_tls_static_size is provided by dl-open.c

     to request some surplus that permits dynamic loading of modules with

     IE-model TLS.  */

#if TLS_TCB_AT_TP

  /* Align the TCB offset to the maximum alignment, as

     _dl_allocate_tls_storage (in elf/dl-tls.c) does using __libc_memalign

     and dl_tls_static_align.  */

  tcb_offset = roundup (memsz + GL(dl_tls_static_size), max_align);

  tlsblock = __sbrk (tcb_offset + TLS_INIT_TCB_SIZE + max_align);

#elif TLS_DTV_AT_TP

  tcb_offset = roundup (TLS_INIT_TCB_SIZE, align ?: 1);

  tlsblock = __sbrk (tcb_offset + memsz + max_align

		     + TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));

  tlsblock += TLS_PRE_TCB_SIZE;

#else

  /* In case a model with a different layout for the TCB and DTV

     is defined add another #elif here and in the following #ifs.  */

# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"

#endif

  /* Align the TLS block.  */

  tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)

		       & ~(max_align - 1));

  /* Initialize the dtv.  [0] is the length, [1] the generation counter.  */

  _dl_static_dtv[0].counter = (sizeof (_dl_static_dtv) / sizeof (_dl_static_dtv[0])) - 2;

  // _dl_static_dtv[1].counter = 0;		would be needed if not already done

  /* Initialize the TLS block.  */

#if TLS_TCB_AT_TP

  _dl_static_dtv[2].pointer.val = ((char *) tlsblock + tcb_offset

			       - roundup (memsz, align ?: 1));

  main_map->l_tls_offset = roundup (memsz, align ?: 1);

#elif TLS_DTV_AT_TP

  _dl_static_dtv[2].pointer.val = (char *) tlsblock + tcb_offset;

  main_map->l_tls_offset = tcb_offset;

#else

# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"

#endif

  _dl_static_dtv[2].pointer.to_free = NULL;

  /* sbrk gives us zero'd memory, so we don't need to clear the remainder.  */

  memcpy (_dl_static_dtv[2].pointer.val, initimage, filesz);

  /* Install the pointer to the dtv.  */

  /* Initialize the thread pointer.  */

#if TLS_TCB_AT_TP

  INSTALL_DTV ((char *) tlsblock + tcb_offset, _dl_static_dtv);

  const char *lossage = TLS_INIT_TP ((char *) tlsblock + tcb_offset);

#elif TLS_DTV_AT_TP

  INSTALL_DTV (tlsblock, _dl_static_dtv);

  const char *lossage = TLS_INIT_TP (tlsblock);

#else

# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"

#endif

  if (__builtin_expect (lossage != NULL, 0))

    _startup_fatal (lossage);

  /* Update the executable's link map with enough information to make

     the TLS routines happy.  */

  main_map->l_tls_align = align;

  main_map->l_tls_blocksize = memsz;

  main_map->l_tls_initimage = initimage;

  main_map->l_tls_initimage_size = filesz;

  main_map->l_tls_modid = 1;

  init_slotinfo ();

  // static_slotinfo.si.slotinfo[1].gen = 0; already zero

  static_slotinfo.si.slotinfo[1].map = main_map;

  memsz = roundup (memsz, align ?: 1);

#if TLS_DTV_AT_TP

  memsz += tcb_offset;

#endif

  init_static_tls (memsz, MAX (TLS_TCB_ALIGN, max_align));

}