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, 2 insertions, 77 deletions

diff --git a/libio/wfileops.c b/libio/wfileops.c
index cecea21c1c..f16f6db1c3 100644
--- a/libio/wfileops.c
+++ b/libio/wfileops.c
@@ -328,7 +328,7 @@ _IO_wfile_underflow (FILE *fp)
 libc_hidden_def (_IO_wfile_underflow)
 
 
-static wint_t
+wint_t
 _IO_wfile_underflow_mmap (FILE *fp)
 {
   struct _IO_codecvt *cd;
@@ -389,7 +389,7 @@ _IO_wfile_underflow_mmap (FILE *fp)
   return WEOF;
 }
 
-static wint_t
+wint_t
 _IO_wfile_underflow_maybe_mmap (FILE *fp)
 {
   /* This is the first read attempt.  Doing the underflow will choose mmap
@@ -1017,78 +1017,3 @@ _IO_wfile_xsputn (FILE *f, const void *data, size_t n)
   return n - to_do;
 }
 libc_hidden_def (_IO_wfile_xsputn)
-
-
-const struct _IO_jump_t _IO_wfile_jumps libio_vtable =
-{
-  JUMP_INIT_DUMMY,
-  JUMP_INIT(finish, _IO_new_file_finish),
-  JUMP_INIT(overflow, (_IO_overflow_t) _IO_wfile_overflow),
-  JUMP_INIT(underflow, (_IO_underflow_t) _IO_wfile_underflow),
-  JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
-  JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wdefault_pbackfail),
-  JUMP_INIT(xsputn, _IO_wfile_xsputn),
-  JUMP_INIT(xsgetn, _IO_file_xsgetn),
-  JUMP_INIT(seekoff, _IO_wfile_seekoff),
-  JUMP_INIT(seekpos, _IO_default_seekpos),
-  JUMP_INIT(setbuf, _IO_new_file_setbuf),
-  JUMP_INIT(sync, (_IO_sync_t) _IO_wfile_sync),
-  JUMP_INIT(doallocate, _IO_wfile_doallocate),
-  JUMP_INIT(read, _IO_file_read),
-  JUMP_INIT(write, _IO_new_file_write),
-  JUMP_INIT(seek, _IO_file_seek),
-  JUMP_INIT(close, _IO_file_close),
-  JUMP_INIT(stat, _IO_file_stat),
-  JUMP_INIT(showmanyc, _IO_default_showmanyc),
-  JUMP_INIT(imbue, _IO_default_imbue)
-};
-libc_hidden_data_def (_IO_wfile_jumps)
-
-
-const struct _IO_jump_t _IO_wfile_jumps_mmap libio_vtable =
-{
-  JUMP_INIT_DUMMY,
-  JUMP_INIT(finish, _IO_new_file_finish),
-  JUMP_INIT(overflow, (_IO_overflow_t) _IO_wfile_overflow),
-  JUMP_INIT(underflow, (_IO_underflow_t) _IO_wfile_underflow_mmap),
-  JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
-  JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wdefault_pbackfail),
-  JUMP_INIT(xsputn, _IO_wfile_xsputn),
-  JUMP_INIT(xsgetn, _IO_file_xsgetn),
-  JUMP_INIT(seekoff, _IO_wfile_seekoff),
-  JUMP_INIT(seekpos, _IO_default_seekpos),
-  JUMP_INIT(setbuf, _IO_file_setbuf_mmap),
-  JUMP_INIT(sync, (_IO_sync_t) _IO_wfile_sync),
-  JUMP_INIT(doallocate, _IO_wfile_doallocate),
-  JUMP_INIT(read, _IO_file_read),
-  JUMP_INIT(write, _IO_new_file_write),
-  JUMP_INIT(seek, _IO_file_seek),
-  JUMP_INIT(close, _IO_file_close_mmap),
-  JUMP_INIT(stat, _IO_file_stat),
-  JUMP_INIT(showmanyc, _IO_default_showmanyc),
-  JUMP_INIT(imbue, _IO_default_imbue)
-};
-
-const struct _IO_jump_t _IO_wfile_jumps_maybe_mmap libio_vtable =
-{
-  JUMP_INIT_DUMMY,
-  JUMP_INIT(finish, _IO_new_file_finish),
-  JUMP_INIT(overflow, (_IO_overflow_t) _IO_wfile_overflow),
-  JUMP_INIT(underflow, (_IO_underflow_t) _IO_wfile_underflow_maybe_mmap),
-  JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
-  JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wdefault_pbackfail),
-  JUMP_INIT(xsputn, _IO_wfile_xsputn),
-  JUMP_INIT(xsgetn, _IO_file_xsgetn),
-  JUMP_INIT(seekoff, _IO_wfile_seekoff),
-  JUMP_INIT(seekpos, _IO_default_seekpos),
-  JUMP_INIT(setbuf, _IO_file_setbuf_mmap),
-  JUMP_INIT(sync, (_IO_sync_t) _IO_wfile_sync),
-  JUMP_INIT(doallocate, _IO_wfile_doallocate),
-  JUMP_INIT(read, _IO_file_read),
-  JUMP_INIT(write, _IO_new_file_write),
-  JUMP_INIT(seek, _IO_file_seek),
-  JUMP_INIT(close, _IO_file_close),
-  JUMP_INIT(stat, _IO_file_stat),
-  JUMP_INIT(showmanyc, _IO_default_showmanyc),
-  JUMP_INIT(imbue, _IO_default_imbue)
-};