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Update.
2002-07-23 Ulrich Drepper <drepper@redhat.com> * sysdeps/generic/libc-tls.c: New file. * csu/Makefile (routines): Add libc-tls. (static-only-routines): Add libc-tls. * elf/dl-support.c (_dl_phdr): New variable. (_dl_phnum): New variable. (_dl_aux_init): Initialize _dl_phdr and _dl_phnum from aux vector. * sysdeps/generic/libc-start.c (__libc_start_main): Reorganize code for !SHARED. First look through auxiliary vector. If TLS always call __pthread_initialize_minimal. * sysdeps/generic/dl-tls.c (_dl_allocate_tls): Make sure size argument in mmap call is never zero.
This commit is contained in:
Ulrich Drepper
182
sysdeps/generic/libc-tls.c
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182
sysdeps/generic/libc-tls.c
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/* Initialization code for TLS in statically linked application.
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Copyright (C) 2002 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <ldsodefs.h>
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#include <tls.h>
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#include <unistd.h>
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#ifdef USE_TLS
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extern ElfW(Phdr) *_dl_phdr;
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extern size_t _dl_phnum;
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/* DTV with just one element plus overhead. */
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static dtv_t static_dtv[3];
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static struct
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{
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struct dtv_slotinfo_list si;
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/* The dtv_slotinfo_list data structure does not include the actual
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informatin since it is defined as an array of size zero. We
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define here the necessary entries. Not that it is not important
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whether there is padding or not since we will always access the
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informatin through the 'si' element. */
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struct dtv_slotinfo info[2 + TLS_SLOTINFO_SURPLUS];
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} static_slotinfo;
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/* Fake link map for the application. */
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static struct link_map static_map;
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void
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__libc_setup_tls (size_t tcbsize, size_t tcbalign)
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{
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void *tlsblock;
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size_t memsz = 0;
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size_t filesz = 0;
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off_t offset = 0;
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size_t align = 0;
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size_t max_align = tcbalign;
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size_t loadaddr = ~0ul;
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size_t tcb_offset;
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/* Look through the TLS segment if there is any. */
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if (_dl_phdr != NULL)
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{
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ElfW(Phdr) *phdr = _dl_phdr;
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size_t phnum = _dl_phnum;
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while (phnum-- > 0)
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if (phdr->p_type == PT_TLS)
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{
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/* Remember the values we need. */
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memsz = phdr->p_memsz;
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filesz = phdr->p_filesz;
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offset = phdr->p_offset;
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align = phdr->p_align;
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if (phdr->p_align > max_align)
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max_align = phdr->p_align;
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}
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else if (phdr->p_type == PT_LOAD)
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{
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/* We have to find the load address which is not easy.
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Look for the load segment with the lowest address. */
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if (phdr->p_vaddr < loadaddr)
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loadaddr = phdr->p_type;
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}
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}
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if (memsz == 0 && tcbsize == 0)
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/* We do not need a TLS block and no thread descriptor. */
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return;
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/* We have to set up the TCB block which also (possibly) contains
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'errno'. Therefore we avoid 'malloc' which might touch 'errno'.
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Instead we use 'sbrk' which would only uses 'errno' if it fails.
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In this case we are right away out of memory and the user gets
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what she/he deserves. */
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# if TLS_TCB_AT_TP
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tlsblock = __sbrk (roundup (memsz, tcbalign) + tcbsize + max_align);
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# elif TLS_DTV_AT_TP
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tlsblock = __sbrk (roundup (tcbsize, align) + memsz + max_align);
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# else
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/* In case a model with a different layout for the TCB and DTV
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is defined add another #elif here and in the following #ifs. */
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# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
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# endif
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/* Align the TLS block. */
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tlsblock = (void *) (((uintptr_t) tlsblock + max_align - 1)
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& ~(max_align - 1));
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/* Initialize the dtv. [0] is the length, [1] the generation counter. */
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static_dtv[0].counter = 1;
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// static_dtv[1].counter = 0; would be needed if not already done
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/* Initialize the TLS block. */
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# if TLS_TCB_AT_TP
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static_dtv[2].pointer = tlsblock;
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# elif TLS_DTV_AT_TP
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tcb_offset = roundup (tcbsize, align);
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static_dtv[2].pointer = (char *) tlsblock + tcb_offset;
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# else
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# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
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# endif
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memset (__mempcpy (static_dtv[2].pointer, (char *) loadaddr + offset,
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filesz),
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'\0', memsz - filesz);
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/* Install the pointer to the dtv. */
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/* Initialize the thread pointer. */
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# if TLS_TCB_AT_TP
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tcb_offset = roundup (memsz, tcbalign);
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INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);
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TLS_INIT_TP ((char *) tlsblock + tcb_offset);
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# elif TLS_DTV_AT_TP
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INSTALL_DTV (tlsblock, static_dtv);
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TLS_INIT_TP (tlsblock);
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# else
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# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
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# endif
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/* We have to create a fake link map which normally would be created
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by the dynamic linker. It just has to have enough informatino to
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make the TLS routines happy. */
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static_map.l_tls_align = align;
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static_map.l_tls_blocksize = memsz;
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static_map.l_tls_initimage_size = filesz;
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static_map.l_tls_offset = offset;
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static_map.l_type = lt_executable;
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static_map.l_tls_modid = 1;
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/* Create the slotinfo list. */
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static_slotinfo.si.len = 1; /* Only one element. */
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// static_slotinfo.si.next = NULL; already zero
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static_slotinfo.si.slotinfo[1].gen = 0;
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static_slotinfo.si.slotinfo[1].map = &static_map;
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/* The slotinfo list. Will be extended by the code doing dynamic
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linking. */
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GL(dl_tls_max_dtv_idx) = 1;
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GL(dl_tls_dtv_slotinfo_list) = &static_slotinfo.si;
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/* That is the size of the TLS memory for this object. */
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# if TLS_TCB_AT_TP
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GL(dl_tls_static_size) = roundup (memsz, align ?: 1) + tcbsize;
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#else
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GL(dl_tls_static_size) = roundup (memsz, align ?: 1);
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#endif
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}
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/* This is the minimal initialization function used when libpthread is
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not used. */
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void
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__attribute__ ((weak))
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__pthread_initialize_minimal (void)
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{
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__libc_setup_tls (0, 1);
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}
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#endif
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