libio: Remove the usage of __libc_IO_vtables

Instead of using a special ELF section along with a linker script
directive to put the IO vtables within the RELRO section, the libio
vtables are all moved to an array marked as data.relro (so linker
will place in the RELRO segment without the need of extra directives).

To avoid static linking namespace issues and including all vtable
referenced objects, all required function pointers are set to weak alias.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 0 insertions, 25 deletions

diff --git a/libio/iopopen.c b/libio/iopopen.c
index d0545ad5ea..a64033e60f 100644
--- a/libio/iopopen.c
+++ b/libio/iopopen.c
@@ -45,8 +45,6 @@ struct _IO_proc_file
 };
 typedef struct _IO_proc_file _IO_proc_file;
 
-static const struct _IO_jump_t _IO_proc_jumps;
-
 static struct _IO_proc_file *proc_file_chain;
 
 #ifdef _IO_MTSAFE_IO
@@ -297,29 +295,6 @@ _IO_new_proc_close (FILE *fp)
   return wstatus;
 }
 
-static const struct _IO_jump_t _IO_proc_jumps libio_vtable = {
-  JUMP_INIT_DUMMY,
-  JUMP_INIT(finish, _IO_new_file_finish),
-  JUMP_INIT(overflow, _IO_new_file_overflow),
-  JUMP_INIT(underflow, _IO_new_file_underflow),
-  JUMP_INIT(uflow, _IO_default_uflow),
-  JUMP_INIT(pbackfail, _IO_default_pbackfail),
-  JUMP_INIT(xsputn, _IO_new_file_xsputn),
-  JUMP_INIT(xsgetn, _IO_default_xsgetn),
-  JUMP_INIT(seekoff, _IO_new_file_seekoff),
-  JUMP_INIT(seekpos, _IO_default_seekpos),
-  JUMP_INIT(setbuf, _IO_new_file_setbuf),
-  JUMP_INIT(sync, _IO_new_file_sync),
-  JUMP_INIT(doallocate, _IO_file_doallocate),
-  JUMP_INIT(read, _IO_file_read),
-  JUMP_INIT(write, _IO_new_file_write),
-  JUMP_INIT(seek, _IO_file_seek),
-  JUMP_INIT(close, _IO_new_proc_close),
-  JUMP_INIT(stat, _IO_file_stat),
-  JUMP_INIT(showmanyc, _IO_default_showmanyc),
-  JUMP_INIT(imbue, _IO_default_imbue)
-};
-
 strong_alias (_IO_new_popen, __new_popen)
 versioned_symbol (libc, _IO_new_popen, _IO_popen, GLIBC_2_1);
 versioned_symbol (libc, __new_popen, popen, GLIBC_2_1);