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Re: Bug in >64k-section ELF handling when linking (with -r)
On Mon, Nov 04, 2002 at 12:54:15PM +0100, Hans-Peter Nilsson wrote:
> It might be that Alan wants to tweak the way allocation of
> finfo.symshndxbuf is handled to that of his patch.
Yes, I think it's worth allocating a signifigantly larger buffer
to start with. max_sym_count, the largest number of local syms
in input bfds, has little to do with the output sym table size.
> Plus it zeros the contents, as the standard says.
Thanks for catching this. :)
> * elf.c (assign_section_numbers): When present, clear reserved
> entries in i_shdrp.
I'm going to simplify this one to just bfd_zalloc the whole array.
Makes it a little more bomb proof.
* elflink.h (struct elf_final_link_info): Add shndxbuf_size.
(elf_bfd_final_link): Don't bother zeroing symtab_hdr fields.
Set up a larger symshndxbuf, and write it out. Free it on
exit rather than freeing symbuf twice. Correct section index
on output section symbol loop.
(elf_link_output_sym): Accumulate symbol extension section
indices, reallocating symshndxbuf rather than writing it out.
(elf_link_flush_output_syms): Don't flush symshndxbuf.
* elf.c (assign_section_numbers): Init i_shdrp to all zero.
Use bfd_zalloc to clear i_shdrp[0] too.
Committed mainline. I'm not too fussed whether this makes it to the
2.13.1 release or not.
Index: bfd/elf.c
===================================================================
RCS file: /cvs/src/src/bfd/elf.c,v
retrieving revision 1.164
diff -u -p -r1.164 elf.c
--- bfd/elf.c 19 Oct 2002 13:52:58 -0000 1.164
+++ bfd/elf.c 4 Nov 2002 12:54:58 -0000
@@ -2671,18 +2671,17 @@ assign_section_numbers (abfd)
/* Set up the list of section header pointers, in agreement with the
indices. */
amt = section_number * sizeof (Elf_Internal_Shdr *);
- i_shdrp = (Elf_Internal_Shdr **) bfd_alloc (abfd, amt);
+ i_shdrp = (Elf_Internal_Shdr **) bfd_zalloc (abfd, amt);
if (i_shdrp == NULL)
return false;
amt = sizeof (Elf_Internal_Shdr);
- i_shdrp[0] = (Elf_Internal_Shdr *) bfd_alloc (abfd, amt);
+ i_shdrp[0] = (Elf_Internal_Shdr *) bfd_zalloc (abfd, amt);
if (i_shdrp[0] == NULL)
{
bfd_release (abfd, i_shdrp);
return false;
}
- memset (i_shdrp[0], 0, sizeof (Elf_Internal_Shdr));
elf_elfsections (abfd) = i_shdrp;
Index: bfd/elflink.h
===================================================================
RCS file: /cvs/src/src/bfd/elflink.h,v
retrieving revision 1.192
diff -u -p -r1.192 elflink.h
--- bfd/elflink.h 22 Oct 2002 21:00:10 -0000 1.192
+++ bfd/elflink.h 4 Nov 2002 12:55:03 -0000
@@ -4494,6 +4494,8 @@ struct elf_final_link_info
size_t symbuf_count;
/* Number of symbols which fit in symbuf. */
size_t symbuf_size;
+ /* And same for symshndxbuf. */
+ size_t shndxbuf_size;
};
static boolean elf_link_output_sym
@@ -4919,6 +4921,7 @@ elf_bfd_final_link (abfd, info)
Elf_Internal_Sym elfsym;
unsigned int i;
Elf_Internal_Shdr *symtab_hdr;
+ Elf_Internal_Shdr *symtab_shndx_hdr;
Elf_Internal_Shdr *symstrtab_hdr;
struct elf_backend_data *bed = get_elf_backend_data (abfd);
struct elf_outext_info eoinfo;
@@ -4972,6 +4975,7 @@ elf_bfd_final_link (abfd, info)
finfo.symbuf = NULL;
finfo.symshndxbuf = NULL;
finfo.symbuf_count = 0;
+ finfo.shndxbuf_size = 0;
finfo.first_tls_sec = NULL;
for (o = abfd->sections; o != (asection *) NULL; o = o->next)
if ((o->flags & SEC_THREAD_LOCAL) != 0
@@ -5192,9 +5196,7 @@ elf_bfd_final_link (abfd, info)
symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
/* sh_name is set in prep_headers. */
symtab_hdr->sh_type = SHT_SYMTAB;
- symtab_hdr->sh_flags = 0;
- symtab_hdr->sh_addr = 0;
- symtab_hdr->sh_size = 0;
+ /* sh_flags, sh_addr and sh_size all start off zero. */
symtab_hdr->sh_entsize = sizeof (Elf_External_Sym);
/* sh_link is set in assign_section_numbers. */
/* sh_info is set below. */
@@ -5221,9 +5223,11 @@ elf_bfd_final_link (abfd, info)
goto error_return;
if (elf_numsections (abfd) > SHN_LORESERVE)
{
- amt = finfo.symbuf_size;
+ /* Wild guess at number of output symbols. realloc'd as needed. */
+ amt = 2 * max_sym_count + elf_numsections (abfd) + 1000;
+ finfo.shndxbuf_size = amt;
amt *= sizeof (Elf_External_Sym_Shndx);
- finfo.symshndxbuf = (Elf_External_Sym_Shndx *) bfd_malloc (amt);
+ finfo.symshndxbuf = (Elf_External_Sym_Shndx *) bfd_zmalloc (amt);
if (finfo.symshndxbuf == NULL)
goto error_return;
}
@@ -5283,7 +5287,7 @@ elf_bfd_final_link (abfd, info)
if (! elf_link_output_sym (&finfo, (const char *) NULL,
&elfsym, o))
goto error_return;
- if (i == SHN_LORESERVE)
+ if (i == SHN_LORESERVE - 1)
i += SHN_HIRESERVE + 1 - SHN_LORESERVE;
}
}
@@ -5558,6 +5562,24 @@ elf_bfd_final_link (abfd, info)
/* Now we know the size of the symtab section. */
off += symtab_hdr->sh_size;
+ symtab_shndx_hdr = &elf_tdata (abfd)->symtab_shndx_hdr;
+ if (symtab_shndx_hdr->sh_name != 0)
+ {
+ symtab_shndx_hdr->sh_type = SHT_SYMTAB_SHNDX;
+ symtab_shndx_hdr->sh_entsize = sizeof (Elf_External_Sym_Shndx);
+ symtab_shndx_hdr->sh_addralign = sizeof (Elf_External_Sym_Shndx);
+ amt = bfd_get_symcount (abfd) * sizeof (Elf_External_Sym_Shndx);
+ symtab_shndx_hdr->sh_size = amt;
+
+ off = _bfd_elf_assign_file_position_for_section (symtab_shndx_hdr,
+ off, true);
+
+ if (bfd_seek (abfd, symtab_shndx_hdr->sh_offset, SEEK_SET) != 0
+ || (bfd_bwrite ((PTR) finfo.symshndxbuf, amt, abfd) != amt))
+ return false;
+ }
+
+
/* Finish up and write out the symbol string table (.strtab)
section. */
symstrtab_hdr = &elf_tdata (abfd)->strtab_hdr;
@@ -5866,7 +5888,7 @@ elf_bfd_final_link (abfd, info)
if (finfo.symbuf != NULL)
free (finfo.symbuf);
if (finfo.symshndxbuf != NULL)
- free (finfo.symbuf);
+ free (finfo.symshndxbuf);
for (o = abfd->sections; o != NULL; o = o->next)
{
if ((o->flags & SEC_RELOC) != 0
@@ -5900,7 +5922,7 @@ elf_bfd_final_link (abfd, info)
if (finfo.symbuf != NULL)
free (finfo.symbuf);
if (finfo.symshndxbuf != NULL)
- free (finfo.symbuf);
+ free (finfo.symshndxbuf);
for (o = abfd->sections; o != NULL; o = o->next)
{
if ((o->flags & SEC_RELOC) != 0
@@ -5959,11 +5981,24 @@ elf_link_output_sym (finfo, name, elfsym
dest = finfo->symbuf + finfo->symbuf_count;
destshndx = finfo->symshndxbuf;
if (destshndx != NULL)
- destshndx += finfo->symbuf_count;
- elf_swap_symbol_out (finfo->output_bfd, elfsym, (PTR) dest, (PTR) destshndx);
- ++finfo->symbuf_count;
+ {
+ if (bfd_get_symcount (finfo->output_bfd) >= finfo->shndxbuf_size)
+ {
+ bfd_size_type amt;
- ++ bfd_get_symcount (finfo->output_bfd);
+ amt = finfo->shndxbuf_size * sizeof (Elf_External_Sym_Shndx);
+ finfo->symshndxbuf = destshndx = bfd_realloc (destshndx, amt * 2);
+ if (destshndx == NULL)
+ return false;
+ memset ((char *) destshndx + amt, 0, amt);
+ finfo->shndxbuf_size *= 2;
+ }
+ destshndx += bfd_get_symcount (finfo->output_bfd);
+ }
+
+ elf_swap_symbol_out (finfo->output_bfd, elfsym, (PTR) dest, (PTR) destshndx);
+ finfo->symbuf_count += 1;
+ bfd_get_symcount (finfo->output_bfd) += 1;
return true;
}
@@ -5988,20 +6023,6 @@ elf_link_flush_output_syms (finfo)
return false;
hdr->sh_size += amt;
-
- if (finfo->symshndxbuf != NULL)
- {
- hdr = &elf_tdata (finfo->output_bfd)->symtab_shndx_hdr;
- pos = hdr->sh_offset + hdr->sh_size;
- amt = finfo->symbuf_count * sizeof (Elf_External_Sym_Shndx);
- if (bfd_seek (finfo->output_bfd, pos, SEEK_SET) != 0
- || (bfd_bwrite ((PTR) finfo->symshndxbuf, amt, finfo->output_bfd)
- != amt))
- return false;
-
- hdr->sh_size += amt;
- }
-
finfo->symbuf_count = 0;
}
--
Alan Modra
IBM OzLabs - Linux Technology Centre