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Moved to csu/errno-loc.c.
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Ulrich Drepper
263
csu/libc-tls.c
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263
csu/libc-tls.c
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/* Initialization code for TLS in statically linked application.
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Copyright (C) 2002, 2003, 2004, 2005 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 <errno.h>
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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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#include <stdio.h>
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#include <sys/param.h>
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#ifdef SHARED
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#error makefile bug, this file is for static only
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#endif
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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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static dtv_t static_dtv[2 + TLS_SLOTINFO_SURPLUS];
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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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information since it is defined as an array of size zero. We define
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here the necessary entries. Note that it is not important whether
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there is padding or not since we will always access the information
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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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/* Highest dtv index currently needed. */
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size_t _dl_tls_max_dtv_idx;
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/* Flag signalling whether there are gaps in the module ID allocation. */
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bool _dl_tls_dtv_gaps;
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/* Information about the dtv slots. */
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struct dtv_slotinfo_list *_dl_tls_dtv_slotinfo_list;
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/* Number of modules in the static TLS block. */
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size_t _dl_tls_static_nelem;
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/* Size of the static TLS block. Giving this initialized value
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preallocates some surplus bytes in the static TLS area. */
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size_t _dl_tls_static_size = 2048;
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/* Size actually allocated in the static TLS block. */
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size_t _dl_tls_static_used;
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/* Alignment requirement of the static TLS block. */
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size_t _dl_tls_static_align;
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/* Generation counter for the dtv. */
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size_t _dl_tls_generation;
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/* Additional definitions needed by TLS initialization. */
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#ifdef TLS_INIT_HELPER
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TLS_INIT_HELPER
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#endif
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static inline void
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init_slotinfo (void)
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{
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/* Create the slotinfo list. */
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static_slotinfo.si.len = (((char *) (&static_slotinfo + 1)
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- (char *) &static_slotinfo.si.slotinfo[0])
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/ sizeof static_slotinfo.si.slotinfo[0]);
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// static_slotinfo.si.next = NULL; already zero
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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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}
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static inline void
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init_static_tls (size_t memsz, size_t align)
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{
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/* That is the size of the TLS memory for this object. The initialized
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value of _dl_tls_static_size is provided by dl-open.c to request some
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surplus that permits dynamic loading of modules with IE-model TLS. */
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GL(dl_tls_static_size) = roundup (memsz + GL(dl_tls_static_size),
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TLS_TCB_ALIGN);
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GL(dl_tls_static_used) = memsz;
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/* The alignment requirement for the static TLS block. */
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GL(dl_tls_static_align) = align;
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/* Number of elements in the static TLS block. */
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GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx);
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}
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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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void *initimage = NULL;
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size_t align = 0;
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size_t max_align = tcbalign;
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size_t tcb_offset;
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ElfW(Phdr) *phdr;
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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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for (phdr = _dl_phdr; phdr < &_dl_phdr[_dl_phnum]; ++phdr)
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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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initimage = (void *) phdr->p_vaddr;
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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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break;
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}
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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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The initialized value of _dl_tls_static_size is provided by dl-open.c
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to request some surplus that permits dynamic loading of modules with
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IE-model TLS. */
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# if TLS_TCB_AT_TP
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tcb_offset = roundup (memsz + GL(dl_tls_static_size), tcbalign);
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tlsblock = __sbrk (tcb_offset + tcbsize + max_align);
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# elif TLS_DTV_AT_TP
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tcb_offset = roundup (tcbsize, align ?: 1);
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tlsblock = __sbrk (tcb_offset + memsz + max_align
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+ TLS_PRE_TCB_SIZE + GL(dl_tls_static_size));
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tlsblock += TLS_PRE_TCB_SIZE;
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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 = (sizeof (static_dtv) / sizeof (static_dtv[0])) - 2;
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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.val = ((char *) tlsblock + tcb_offset
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- roundup (memsz, align ?: 1));
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static_map.l_tls_offset = roundup (memsz, align ?: 1);
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# elif TLS_DTV_AT_TP
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static_dtv[2].pointer.val = (char *) tlsblock + tcb_offset;
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static_map.l_tls_offset = 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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static_dtv[2].pointer.is_static = true;
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/* sbrk gives us zero'd memory, so we don't need to clear the remainder. */
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memcpy (static_dtv[2].pointer.val, initimage, 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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INSTALL_DTV ((char *) tlsblock + tcb_offset, static_dtv);
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const char *lossage = TLS_INIT_TP ((char *) tlsblock + tcb_offset, 0);
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# elif TLS_DTV_AT_TP
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INSTALL_DTV (tlsblock, static_dtv);
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const char *lossage = TLS_INIT_TP (tlsblock, 0);
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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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if (__builtin_expect (lossage != NULL, 0))
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__libc_fatal (lossage);
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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 information 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 = initimage;
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static_map.l_tls_initimage_size = filesz;
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static_map.l_type = lt_executable;
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static_map.l_tls_modid = 1;
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init_slotinfo ();
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// static_slotinfo.si.slotinfo[1].gen = 0; already zero
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static_slotinfo.si.slotinfo[1].map = &static_map;
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memsz = roundup (memsz, align ?: 1);
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# if TLS_TCB_AT_TP
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memsz += tcbsize;
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# elif TLS_DTV_AT_TP
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memsz += tcb_offset;
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# endif
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init_static_tls (memsz, MAX (TLS_TCB_ALIGN, max_align));
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}
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/* This is called only when the data structure setup was skipped at startup,
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when there was no need for it then. Now we have dynamically loaded
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something needing TLS, or libpthread needs it. */
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int
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internal_function
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_dl_tls_setup (void)
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{
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init_slotinfo ();
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init_static_tls (
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# if TLS_TCB_AT_TP
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TLS_TCB_SIZE,
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# else
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0,
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# endif
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TLS_TCB_ALIGN);
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return 0;
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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 (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
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}
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#elif defined NONTLS_INIT_TP
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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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NONTLS_INIT_TP;
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}
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#endif
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