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2.5-18.1
This commit is contained in:
Jakub Jelinek
843
elf/dl-tls.c
Normal file
843
elf/dl-tls.c
Normal file
@ -0,0 +1,843 @@
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||||
/* Thread-local storage handling in the ELF dynamic linker. Generic version.
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||||
Copyright (C) 2002,2003,2004,2005,2006 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, write to the Free
|
||||
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
||||
02111-1307 USA. */
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||||
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#include <assert.h>
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#include <errno.h>
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#include <libintl.h>
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sys/param.h>
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#include <tls.h>
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/* We don't need any of this if TLS is not supported. */
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#ifdef USE_TLS
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# include <dl-tls.h>
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# include <ldsodefs.h>
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/* Amount of excess space to allocate in the static TLS area
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to allow dynamic loading of modules defining IE-model TLS data. */
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# define TLS_STATIC_SURPLUS 64 + DL_NNS * 100
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/* Value used for dtv entries for which the allocation is delayed. */
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# define TLS_DTV_UNALLOCATED ((void *) -1l)
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/* Out-of-memory handler. */
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# ifdef SHARED
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static void
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__attribute__ ((__noreturn__))
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oom (void)
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{
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_dl_fatal_printf ("cannot allocate memory for thread-local data: ABORT\n");
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}
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# endif
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size_t
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internal_function
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_dl_next_tls_modid (void)
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{
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size_t result;
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if (__builtin_expect (GL(dl_tls_dtv_gaps), false))
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{
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size_t disp = 0;
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struct dtv_slotinfo_list *runp = GL(dl_tls_dtv_slotinfo_list);
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/* Note that this branch will never be executed during program
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start since there are no gaps at that time. Therefore it
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does not matter that the dl_tls_dtv_slotinfo is not allocated
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yet when the function is called for the first times.
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NB: the offset +1 is due to the fact that DTV[0] is used
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for something else. */
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result = GL(dl_tls_static_nelem) + 1;
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if (result <= GL(dl_tls_max_dtv_idx))
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do
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{
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while (result - disp < runp->len)
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{
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if (runp->slotinfo[result - disp].map == NULL)
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break;
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++result;
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assert (result <= GL(dl_tls_max_dtv_idx) + 1);
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}
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if (result - disp < runp->len)
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break;
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disp += runp->len;
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}
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while ((runp = runp->next) != NULL);
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if (result > GL(dl_tls_max_dtv_idx))
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{
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/* The new index must indeed be exactly one higher than the
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previous high. */
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assert (result == GL(dl_tls_max_dtv_idx) + 1);
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/* There is no gap anymore. */
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GL(dl_tls_dtv_gaps) = false;
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goto nogaps;
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}
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}
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else
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{
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/* No gaps, allocate a new entry. */
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nogaps:
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result = ++GL(dl_tls_max_dtv_idx);
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}
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return result;
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}
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# ifdef SHARED
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void
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internal_function
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_dl_determine_tlsoffset (void)
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{
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size_t max_align = TLS_TCB_ALIGN;
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size_t freetop = 0;
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size_t freebottom = 0;
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/* The first element of the dtv slot info list is allocated. */
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assert (GL(dl_tls_dtv_slotinfo_list) != NULL);
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/* There is at this point only one element in the
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dl_tls_dtv_slotinfo_list list. */
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assert (GL(dl_tls_dtv_slotinfo_list)->next == NULL);
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struct dtv_slotinfo *slotinfo = GL(dl_tls_dtv_slotinfo_list)->slotinfo;
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/* Determining the offset of the various parts of the static TLS
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block has several dependencies. In addition we have to work
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around bugs in some toolchains.
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Each TLS block from the objects available at link time has a size
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and an alignment requirement. The GNU ld computes the alignment
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||||
requirements for the data at the positions *in the file*, though.
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I.e, it is not simply possible to allocate a block with the size
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of the TLS program header entry. The data is layed out assuming
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that the first byte of the TLS block fulfills
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p_vaddr mod p_align == &TLS_BLOCK mod p_align
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This means we have to add artificial padding at the beginning of
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the TLS block. These bytes are never used for the TLS data in
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this module but the first byte allocated must be aligned
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according to mod p_align == 0 so that the first byte of the TLS
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block is aligned according to p_vaddr mod p_align. This is ugly
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and the linker can help by computing the offsets in the TLS block
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assuming the first byte of the TLS block is aligned according to
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p_align.
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The extra space which might be allocated before the first byte of
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the TLS block need not go unused. The code below tries to use
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that memory for the next TLS block. This can work if the total
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memory requirement for the next TLS block is smaller than the
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gap. */
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# if TLS_TCB_AT_TP
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/* We simply start with zero. */
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size_t offset = 0;
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for (size_t cnt = 0; slotinfo[cnt].map != NULL; ++cnt)
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{
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assert (cnt < GL(dl_tls_dtv_slotinfo_list)->len);
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size_t firstbyte = (-slotinfo[cnt].map->l_tls_firstbyte_offset
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& (slotinfo[cnt].map->l_tls_align - 1));
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size_t off;
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max_align = MAX (max_align, slotinfo[cnt].map->l_tls_align);
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if (freebottom - freetop >= slotinfo[cnt].map->l_tls_blocksize)
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{
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off = roundup (freetop + slotinfo[cnt].map->l_tls_blocksize
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- firstbyte, slotinfo[cnt].map->l_tls_align)
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+ firstbyte;
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if (off <= freebottom)
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{
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freetop = off;
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/* XXX For some architectures we perhaps should store the
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negative offset. */
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slotinfo[cnt].map->l_tls_offset = off;
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continue;
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}
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}
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off = roundup (offset + slotinfo[cnt].map->l_tls_blocksize - firstbyte,
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slotinfo[cnt].map->l_tls_align) + firstbyte;
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if (off > offset + slotinfo[cnt].map->l_tls_blocksize
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+ (freebottom - freetop))
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{
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freetop = offset;
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freebottom = off - slotinfo[cnt].map->l_tls_blocksize;
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}
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offset = off;
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/* XXX For some architectures we perhaps should store the
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negative offset. */
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slotinfo[cnt].map->l_tls_offset = off;
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}
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GL(dl_tls_static_used) = offset;
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GL(dl_tls_static_size) = (roundup (offset + TLS_STATIC_SURPLUS, max_align)
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+ TLS_TCB_SIZE);
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# elif TLS_DTV_AT_TP
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/* The TLS blocks start right after the TCB. */
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size_t offset = TLS_TCB_SIZE;
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for (size_t cnt = 0; slotinfo[cnt].map != NULL; ++cnt)
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{
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assert (cnt < GL(dl_tls_dtv_slotinfo_list)->len);
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size_t firstbyte = (-slotinfo[cnt].map->l_tls_firstbyte_offset
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& (slotinfo[cnt].map->l_tls_align - 1));
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size_t off;
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max_align = MAX (max_align, slotinfo[cnt].map->l_tls_align);
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if (slotinfo[cnt].map->l_tls_blocksize <= freetop - freebottom)
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{
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off = roundup (freebottom, slotinfo[cnt].map->l_tls_align);
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if (off - freebottom < firstbyte)
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off += slotinfo[cnt].map->l_tls_align;
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if (off + slotinfo[cnt].map->l_tls_blocksize - firstbyte <= freetop)
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{
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slotinfo[cnt].map->l_tls_offset = off - firstbyte;
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freebottom = (off + slotinfo[cnt].map->l_tls_blocksize
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- firstbyte);
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continue;
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}
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}
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off = roundup (offset, slotinfo[cnt].map->l_tls_align);
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if (off - offset < firstbyte)
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off += slotinfo[cnt].map->l_tls_align;
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slotinfo[cnt].map->l_tls_offset = off - firstbyte;
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if (off - firstbyte - offset > freetop - freebottom)
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{
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freebottom = offset;
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freetop = off - firstbyte;
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}
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offset = off + slotinfo[cnt].map->l_tls_blocksize - firstbyte;
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}
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GL(dl_tls_static_used) = offset;
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GL(dl_tls_static_size) = roundup (offset + TLS_STATIC_SURPLUS,
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TLS_TCB_ALIGN);
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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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/* The alignment requirement for the static TLS block. */
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GL(dl_tls_static_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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assert (GL(dl_tls_dtv_slotinfo_list) == NULL);
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assert (GL(dl_tls_max_dtv_idx) == 0);
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const size_t nelem = 2 + TLS_SLOTINFO_SURPLUS;
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GL(dl_tls_dtv_slotinfo_list)
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= calloc (1, (sizeof (struct dtv_slotinfo_list)
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+ nelem * sizeof (struct dtv_slotinfo)));
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if (GL(dl_tls_dtv_slotinfo_list) == NULL)
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return -1;
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GL(dl_tls_dtv_slotinfo_list)->len = nelem;
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/* Number of elements in the static TLS block. It can't be zero
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because of various assumptions. The one element is null. */
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GL(dl_tls_static_nelem) = GL(dl_tls_max_dtv_idx) = 1;
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/* This initializes more variables for us. */
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_dl_determine_tlsoffset ();
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return 0;
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}
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rtld_hidden_def (_dl_tls_setup)
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# endif
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static void *
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||||
internal_function
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||||
allocate_dtv (void *result)
|
||||
{
|
||||
dtv_t *dtv;
|
||||
size_t dtv_length;
|
||||
|
||||
/* We allocate a few more elements in the dtv than are needed for the
|
||||
initial set of modules. This should avoid in most cases expansions
|
||||
of the dtv. */
|
||||
dtv_length = GL(dl_tls_max_dtv_idx) + DTV_SURPLUS;
|
||||
dtv = calloc (dtv_length + 2, sizeof (dtv_t));
|
||||
if (dtv != NULL)
|
||||
{
|
||||
/* This is the initial length of the dtv. */
|
||||
dtv[0].counter = dtv_length;
|
||||
|
||||
/* The rest of the dtv (including the generation counter) is
|
||||
Initialize with zero to indicate nothing there. */
|
||||
|
||||
/* Add the dtv to the thread data structures. */
|
||||
INSTALL_DTV (result, dtv);
|
||||
}
|
||||
else
|
||||
result = NULL;
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
|
||||
/* Get size and alignment requirements of the static TLS block. */
|
||||
void
|
||||
internal_function
|
||||
_dl_get_tls_static_info (size_t *sizep, size_t *alignp)
|
||||
{
|
||||
*sizep = GL(dl_tls_static_size);
|
||||
*alignp = GL(dl_tls_static_align);
|
||||
}
|
||||
|
||||
|
||||
void *
|
||||
internal_function
|
||||
_dl_allocate_tls_storage (void)
|
||||
{
|
||||
void *result;
|
||||
size_t size = GL(dl_tls_static_size);
|
||||
|
||||
# if TLS_DTV_AT_TP
|
||||
/* Memory layout is:
|
||||
[ TLS_PRE_TCB_SIZE ] [ TLS_TCB_SIZE ] [ TLS blocks ]
|
||||
^ This should be returned. */
|
||||
size += (TLS_PRE_TCB_SIZE + GL(dl_tls_static_align) - 1)
|
||||
& ~(GL(dl_tls_static_align) - 1);
|
||||
# endif
|
||||
|
||||
/* Allocate a correctly aligned chunk of memory. */
|
||||
result = __libc_memalign (GL(dl_tls_static_align), size);
|
||||
if (__builtin_expect (result != NULL, 1))
|
||||
{
|
||||
/* Allocate the DTV. */
|
||||
void *allocated = result;
|
||||
|
||||
# if TLS_TCB_AT_TP
|
||||
/* The TCB follows the TLS blocks. */
|
||||
result = (char *) result + size - TLS_TCB_SIZE;
|
||||
|
||||
/* Clear the TCB data structure. We can't ask the caller (i.e.
|
||||
libpthread) to do it, because we will initialize the DTV et al. */
|
||||
memset (result, '\0', TLS_TCB_SIZE);
|
||||
# elif TLS_DTV_AT_TP
|
||||
result = (char *) result + size - GL(dl_tls_static_size);
|
||||
|
||||
/* Clear the TCB data structure and TLS_PRE_TCB_SIZE bytes before it.
|
||||
We can't ask the caller (i.e. libpthread) to do it, because we will
|
||||
initialize the DTV et al. */
|
||||
memset ((char *) result - TLS_PRE_TCB_SIZE, '\0',
|
||||
TLS_PRE_TCB_SIZE + TLS_TCB_SIZE);
|
||||
# endif
|
||||
|
||||
result = allocate_dtv (result);
|
||||
if (result == NULL)
|
||||
free (allocated);
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
|
||||
void *
|
||||
internal_function
|
||||
_dl_allocate_tls_init (void *result)
|
||||
{
|
||||
if (result == NULL)
|
||||
/* The memory allocation failed. */
|
||||
return NULL;
|
||||
|
||||
dtv_t *dtv = GET_DTV (result);
|
||||
struct dtv_slotinfo_list *listp;
|
||||
size_t total = 0;
|
||||
size_t maxgen = 0;
|
||||
|
||||
/* We have to prepare the dtv for all currently loaded modules using
|
||||
TLS. For those which are dynamically loaded we add the values
|
||||
indicating deferred allocation. */
|
||||
listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
while (1)
|
||||
{
|
||||
size_t cnt;
|
||||
|
||||
for (cnt = total == 0 ? 1 : 0; cnt < listp->len; ++cnt)
|
||||
{
|
||||
struct link_map *map;
|
||||
void *dest;
|
||||
|
||||
/* Check for the total number of used slots. */
|
||||
if (total + cnt > GL(dl_tls_max_dtv_idx))
|
||||
break;
|
||||
|
||||
map = listp->slotinfo[cnt].map;
|
||||
if (map == NULL)
|
||||
/* Unused entry. */
|
||||
continue;
|
||||
|
||||
/* Keep track of the maximum generation number. This might
|
||||
not be the generation counter. */
|
||||
maxgen = MAX (maxgen, listp->slotinfo[cnt].gen);
|
||||
|
||||
if (map->l_tls_offset == NO_TLS_OFFSET)
|
||||
{
|
||||
/* For dynamically loaded modules we simply store
|
||||
the value indicating deferred allocation. */
|
||||
dtv[map->l_tls_modid].pointer.val = TLS_DTV_UNALLOCATED;
|
||||
dtv[map->l_tls_modid].pointer.is_static = false;
|
||||
continue;
|
||||
}
|
||||
|
||||
assert (map->l_tls_modid == cnt);
|
||||
assert (map->l_tls_blocksize >= map->l_tls_initimage_size);
|
||||
# if TLS_TCB_AT_TP
|
||||
assert ((size_t) map->l_tls_offset >= map->l_tls_blocksize);
|
||||
dest = (char *) result - map->l_tls_offset;
|
||||
# elif TLS_DTV_AT_TP
|
||||
dest = (char *) result + map->l_tls_offset;
|
||||
# else
|
||||
# error "Either TLS_TCB_AT_TP or TLS_DTV_AT_TP must be defined"
|
||||
# endif
|
||||
|
||||
/* Copy the initialization image and clear the BSS part. */
|
||||
dtv[map->l_tls_modid].pointer.val = dest;
|
||||
dtv[map->l_tls_modid].pointer.is_static = true;
|
||||
memset (__mempcpy (dest, map->l_tls_initimage,
|
||||
map->l_tls_initimage_size), '\0',
|
||||
map->l_tls_blocksize - map->l_tls_initimage_size);
|
||||
}
|
||||
|
||||
total += cnt;
|
||||
if (total >= GL(dl_tls_max_dtv_idx))
|
||||
break;
|
||||
|
||||
listp = listp->next;
|
||||
assert (listp != NULL);
|
||||
}
|
||||
|
||||
/* The DTV version is up-to-date now. */
|
||||
dtv[0].counter = maxgen;
|
||||
|
||||
return result;
|
||||
}
|
||||
rtld_hidden_def (_dl_allocate_tls_init)
|
||||
|
||||
void *
|
||||
internal_function
|
||||
_dl_allocate_tls (void *mem)
|
||||
{
|
||||
return _dl_allocate_tls_init (mem == NULL
|
||||
? _dl_allocate_tls_storage ()
|
||||
: allocate_dtv (mem));
|
||||
}
|
||||
rtld_hidden_def (_dl_allocate_tls)
|
||||
|
||||
|
||||
void
|
||||
internal_function
|
||||
_dl_deallocate_tls (void *tcb, bool dealloc_tcb)
|
||||
{
|
||||
dtv_t *dtv = GET_DTV (tcb);
|
||||
|
||||
/* We need to free the memory allocated for non-static TLS. */
|
||||
for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt)
|
||||
if (! dtv[1 + cnt].pointer.is_static
|
||||
&& dtv[1 + cnt].pointer.val != TLS_DTV_UNALLOCATED)
|
||||
free (dtv[1 + cnt].pointer.val);
|
||||
|
||||
/* The array starts with dtv[-1]. */
|
||||
#ifdef SHARED
|
||||
if (dtv != GL(dl_initial_dtv))
|
||||
#endif
|
||||
free (dtv - 1);
|
||||
|
||||
if (dealloc_tcb)
|
||||
{
|
||||
# if TLS_TCB_AT_TP
|
||||
/* The TCB follows the TLS blocks. Back up to free the whole block. */
|
||||
tcb -= GL(dl_tls_static_size) - TLS_TCB_SIZE;
|
||||
# elif TLS_DTV_AT_TP
|
||||
/* Back up the TLS_PRE_TCB_SIZE bytes. */
|
||||
tcb -= (TLS_PRE_TCB_SIZE + GL(dl_tls_static_align) - 1)
|
||||
& ~(GL(dl_tls_static_align) - 1);
|
||||
# endif
|
||||
free (tcb);
|
||||
}
|
||||
}
|
||||
rtld_hidden_def (_dl_deallocate_tls)
|
||||
|
||||
|
||||
# ifdef SHARED
|
||||
/* The __tls_get_addr function has two basic forms which differ in the
|
||||
arguments. The IA-64 form takes two parameters, the module ID and
|
||||
offset. The form used, among others, on IA-32 takes a reference to
|
||||
a special structure which contain the same information. The second
|
||||
form seems to be more often used (in the moment) so we default to
|
||||
it. Users of the IA-64 form have to provide adequate definitions
|
||||
of the following macros. */
|
||||
# ifndef GET_ADDR_ARGS
|
||||
# define GET_ADDR_ARGS tls_index *ti
|
||||
# endif
|
||||
# ifndef GET_ADDR_MODULE
|
||||
# define GET_ADDR_MODULE ti->ti_module
|
||||
# endif
|
||||
# ifndef GET_ADDR_OFFSET
|
||||
# define GET_ADDR_OFFSET ti->ti_offset
|
||||
# endif
|
||||
|
||||
|
||||
static void *
|
||||
allocate_and_init (struct link_map *map)
|
||||
{
|
||||
void *newp;
|
||||
|
||||
newp = __libc_memalign (map->l_tls_align, map->l_tls_blocksize);
|
||||
if (newp == NULL)
|
||||
oom ();
|
||||
|
||||
/* Initialize the memory. */
|
||||
memset (__mempcpy (newp, map->l_tls_initimage, map->l_tls_initimage_size),
|
||||
'\0', map->l_tls_blocksize - map->l_tls_initimage_size);
|
||||
|
||||
return newp;
|
||||
}
|
||||
|
||||
|
||||
struct link_map *
|
||||
_dl_update_slotinfo (unsigned long int req_modid)
|
||||
{
|
||||
struct link_map *the_map = NULL;
|
||||
dtv_t *dtv = THREAD_DTV ();
|
||||
|
||||
/* The global dl_tls_dtv_slotinfo array contains for each module
|
||||
index the generation counter current when the entry was created.
|
||||
This array never shrinks so that all module indices which were
|
||||
valid at some time can be used to access it. Before the first
|
||||
use of a new module index in this function the array was extended
|
||||
appropriately. Access also does not have to be guarded against
|
||||
modifications of the array. It is assumed that pointer-size
|
||||
values can be read atomically even in SMP environments. It is
|
||||
possible that other threads at the same time dynamically load
|
||||
code and therefore add to the slotinfo list. This is a problem
|
||||
since we must not pick up any information about incomplete work.
|
||||
The solution to this is to ignore all dtv slots which were
|
||||
created after the one we are currently interested. We know that
|
||||
dynamic loading for this module is completed and this is the last
|
||||
load operation we know finished. */
|
||||
unsigned long int idx = req_modid;
|
||||
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
|
||||
while (idx >= listp->len)
|
||||
{
|
||||
idx -= listp->len;
|
||||
listp = listp->next;
|
||||
}
|
||||
|
||||
if (dtv[0].counter < listp->slotinfo[idx].gen)
|
||||
{
|
||||
/* The generation counter for the slot is higher than what the
|
||||
current dtv implements. We have to update the whole dtv but
|
||||
only those entries with a generation counter <= the one for
|
||||
the entry we need. */
|
||||
size_t new_gen = listp->slotinfo[idx].gen;
|
||||
size_t total = 0;
|
||||
|
||||
/* We have to look through the entire dtv slotinfo list. */
|
||||
listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
do
|
||||
{
|
||||
for (size_t cnt = total == 0 ? 1 : 0; cnt < listp->len; ++cnt)
|
||||
{
|
||||
size_t gen = listp->slotinfo[cnt].gen;
|
||||
|
||||
if (gen > new_gen)
|
||||
/* This is a slot for a generation younger than the
|
||||
one we are handling now. It might be incompletely
|
||||
set up so ignore it. */
|
||||
continue;
|
||||
|
||||
/* If the entry is older than the current dtv layout we
|
||||
know we don't have to handle it. */
|
||||
if (gen <= dtv[0].counter)
|
||||
continue;
|
||||
|
||||
/* If there is no map this means the entry is empty. */
|
||||
struct link_map *map = listp->slotinfo[cnt].map;
|
||||
if (map == NULL)
|
||||
{
|
||||
/* If this modid was used at some point the memory
|
||||
might still be allocated. */
|
||||
if (! dtv[total + cnt].pointer.is_static
|
||||
&& dtv[total + cnt].pointer.val != TLS_DTV_UNALLOCATED)
|
||||
{
|
||||
free (dtv[total + cnt].pointer.val);
|
||||
dtv[total + cnt].pointer.val = TLS_DTV_UNALLOCATED;
|
||||
}
|
||||
|
||||
continue;
|
||||
}
|
||||
|
||||
/* Check whether the current dtv array is large enough. */
|
||||
size_t modid = map->l_tls_modid;
|
||||
assert (total + cnt == modid);
|
||||
if (dtv[-1].counter < modid)
|
||||
{
|
||||
/* Reallocate the dtv. */
|
||||
dtv_t *newp;
|
||||
size_t newsize = GL(dl_tls_max_dtv_idx) + DTV_SURPLUS;
|
||||
size_t oldsize = dtv[-1].counter;
|
||||
|
||||
assert (map->l_tls_modid <= newsize);
|
||||
|
||||
if (dtv == GL(dl_initial_dtv))
|
||||
{
|
||||
/* This is the initial dtv that was allocated
|
||||
during rtld startup using the dl-minimal.c
|
||||
malloc instead of the real malloc. We can't
|
||||
free it, we have to abandon the old storage. */
|
||||
|
||||
newp = malloc ((2 + newsize) * sizeof (dtv_t));
|
||||
if (newp == NULL)
|
||||
oom ();
|
||||
memcpy (newp, &dtv[-1], oldsize * sizeof (dtv_t));
|
||||
}
|
||||
else
|
||||
{
|
||||
newp = realloc (&dtv[-1],
|
||||
(2 + newsize) * sizeof (dtv_t));
|
||||
if (newp == NULL)
|
||||
oom ();
|
||||
}
|
||||
|
||||
newp[0].counter = newsize;
|
||||
|
||||
/* Clear the newly allocated part. */
|
||||
memset (newp + 2 + oldsize, '\0',
|
||||
(newsize - oldsize) * sizeof (dtv_t));
|
||||
|
||||
/* Point dtv to the generation counter. */
|
||||
dtv = &newp[1];
|
||||
|
||||
/* Install this new dtv in the thread data
|
||||
structures. */
|
||||
INSTALL_NEW_DTV (dtv);
|
||||
}
|
||||
|
||||
/* If there is currently memory allocate for this
|
||||
dtv entry free it. */
|
||||
/* XXX Ideally we will at some point create a memory
|
||||
pool. */
|
||||
if (! dtv[modid].pointer.is_static
|
||||
&& dtv[modid].pointer.val != TLS_DTV_UNALLOCATED)
|
||||
/* Note that free is called for NULL is well. We
|
||||
deallocate even if it is this dtv entry we are
|
||||
supposed to load. The reason is that we call
|
||||
memalign and not malloc. */
|
||||
free (dtv[modid].pointer.val);
|
||||
|
||||
/* This module is loaded dynamically- We defer memory
|
||||
allocation. */
|
||||
dtv[modid].pointer.is_static = false;
|
||||
dtv[modid].pointer.val = TLS_DTV_UNALLOCATED;
|
||||
|
||||
if (modid == req_modid)
|
||||
the_map = map;
|
||||
}
|
||||
|
||||
total += listp->len;
|
||||
}
|
||||
while ((listp = listp->next) != NULL);
|
||||
|
||||
/* This will be the new maximum generation counter. */
|
||||
dtv[0].counter = new_gen;
|
||||
}
|
||||
|
||||
return the_map;
|
||||
}
|
||||
|
||||
|
||||
/* The generic dynamic and local dynamic model cannot be used in
|
||||
statically linked applications. */
|
||||
void *
|
||||
__tls_get_addr (GET_ADDR_ARGS)
|
||||
{
|
||||
dtv_t *dtv = THREAD_DTV ();
|
||||
struct link_map *the_map = NULL;
|
||||
void *p;
|
||||
|
||||
if (__builtin_expect (dtv[0].counter != GL(dl_tls_generation), 0))
|
||||
the_map = _dl_update_slotinfo (GET_ADDR_MODULE);
|
||||
|
||||
p = dtv[GET_ADDR_MODULE].pointer.val;
|
||||
|
||||
if (__builtin_expect (p == TLS_DTV_UNALLOCATED, 0))
|
||||
{
|
||||
/* The allocation was deferred. Do it now. */
|
||||
if (the_map == NULL)
|
||||
{
|
||||
/* Find the link map for this module. */
|
||||
size_t idx = GET_ADDR_MODULE;
|
||||
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
|
||||
while (idx >= listp->len)
|
||||
{
|
||||
idx -= listp->len;
|
||||
listp = listp->next;
|
||||
}
|
||||
|
||||
the_map = listp->slotinfo[idx].map;
|
||||
}
|
||||
|
||||
p = dtv[GET_ADDR_MODULE].pointer.val = allocate_and_init (the_map);
|
||||
dtv[GET_ADDR_MODULE].pointer.is_static = false;
|
||||
}
|
||||
|
||||
return (char *) p + GET_ADDR_OFFSET;
|
||||
}
|
||||
# endif
|
||||
|
||||
|
||||
/* Look up the module's TLS block as for __tls_get_addr,
|
||||
but never touch anything. Return null if it's not allocated yet. */
|
||||
void *
|
||||
internal_function
|
||||
_dl_tls_get_addr_soft (struct link_map *l)
|
||||
{
|
||||
if (__builtin_expect (l->l_tls_modid == 0, 0))
|
||||
/* This module has no TLS segment. */
|
||||
return NULL;
|
||||
|
||||
dtv_t *dtv = THREAD_DTV ();
|
||||
if (__builtin_expect (dtv[0].counter != GL(dl_tls_generation), 0))
|
||||
{
|
||||
/* This thread's DTV is not completely current,
|
||||
but it might already cover this module. */
|
||||
|
||||
if (l->l_tls_modid >= dtv[-1].counter)
|
||||
/* Nope. */
|
||||
return NULL;
|
||||
|
||||
size_t idx = l->l_tls_modid;
|
||||
struct dtv_slotinfo_list *listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
while (idx >= listp->len)
|
||||
{
|
||||
idx -= listp->len;
|
||||
listp = listp->next;
|
||||
}
|
||||
|
||||
/* We've reached the slot for this module.
|
||||
If its generation counter is higher than the DTV's,
|
||||
this thread does not know about this module yet. */
|
||||
if (dtv[0].counter < listp->slotinfo[idx].gen)
|
||||
return NULL;
|
||||
}
|
||||
|
||||
void *data = dtv[l->l_tls_modid].pointer.val;
|
||||
if (__builtin_expect (data == TLS_DTV_UNALLOCATED, 0))
|
||||
/* The DTV is current, but this thread has not yet needed
|
||||
to allocate this module's segment. */
|
||||
data = NULL;
|
||||
|
||||
return data;
|
||||
}
|
||||
|
||||
|
||||
void
|
||||
_dl_add_to_slotinfo (struct link_map *l)
|
||||
{
|
||||
/* Now that we know the object is loaded successfully add
|
||||
modules containing TLS data to the dtv info table. We
|
||||
might have to increase its size. */
|
||||
struct dtv_slotinfo_list *listp;
|
||||
struct dtv_slotinfo_list *prevp;
|
||||
size_t idx = l->l_tls_modid;
|
||||
|
||||
/* Find the place in the dtv slotinfo list. */
|
||||
listp = GL(dl_tls_dtv_slotinfo_list);
|
||||
prevp = NULL; /* Needed to shut up gcc. */
|
||||
do
|
||||
{
|
||||
/* Does it fit in the array of this list element? */
|
||||
if (idx < listp->len)
|
||||
break;
|
||||
idx -= listp->len;
|
||||
prevp = listp;
|
||||
listp = listp->next;
|
||||
}
|
||||
while (listp != NULL);
|
||||
|
||||
if (listp == NULL)
|
||||
{
|
||||
/* When we come here it means we have to add a new element
|
||||
to the slotinfo list. And the new module must be in
|
||||
the first slot. */
|
||||
assert (idx == 0);
|
||||
|
||||
listp = prevp->next = (struct dtv_slotinfo_list *)
|
||||
malloc (sizeof (struct dtv_slotinfo_list)
|
||||
+ TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo));
|
||||
if (listp == NULL)
|
||||
{
|
||||
/* We ran out of memory. We will simply fail this
|
||||
call but don't undo anything we did so far. The
|
||||
application will crash or be terminated anyway very
|
||||
soon. */
|
||||
|
||||
/* We have to do this since some entries in the dtv
|
||||
slotinfo array might already point to this
|
||||
generation. */
|
||||
++GL(dl_tls_generation);
|
||||
|
||||
_dl_signal_error (ENOMEM, "dlopen", NULL, N_("\
|
||||
cannot create TLS data structures"));
|
||||
}
|
||||
|
||||
listp->len = TLS_SLOTINFO_SURPLUS;
|
||||
listp->next = NULL;
|
||||
memset (listp->slotinfo, '\0',
|
||||
TLS_SLOTINFO_SURPLUS * sizeof (struct dtv_slotinfo));
|
||||
}
|
||||
|
||||
/* Add the information into the slotinfo data structure. */
|
||||
listp->slotinfo[idx].map = l;
|
||||
listp->slotinfo[idx].gen = GL(dl_tls_generation) + 1;
|
||||
}
|
||||
#endif /* use TLS */
|
||||
Reference in New Issue
Block a user