esp-idf/components/esp_rom/esp32s2/ld/esp32s2.rom.newlib-time.ld
Ivan Grokhotkov 24c20d188e esp_rom: remove functions which depend on sizeof(struct stat)
...and all their callers.

With the upcoming switch from sizeof(time_t)==4 to sizeof(time_t)==8,
sizeof(struct stat) is also increasing.

A few newlib functions present in ROM allocate 'struct stat' on the
stack and call _fstat_r on this structure. The implementation of
fstat is provided in ESP-IDF. This implementation will often do
memset(st, 0, sizeof(*st)), where st is 'struct stat*', before setting
some fields of this structure. If IDF is built with sizeof(st)
different from sizeof(st) which ROM was built with, this will lead
to an out-of-bounds write and a stack corruption.

This commit removes problematic ROM functions from the linker script.
Here are the functions which allocate 'struct stat':
* _isatty_r (in ROM)
* __swhatbuf_r, called by __smakebuf_r, called by __swsetup_r and
  __srefill_r (in ROM)
* _fseeko_r (not in ROM)
* glob2 (not in ROM)
* _gettemp (not in ROM)

As a result, these functions are used from libc.a, and use correct
size of 'stat' structure.

Closes https://github.com/espressif/esp-idf/issues/7980
2022-01-06 15:20:04 +01:00

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/*
* SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
/* These are the newlib functions and the .bss/.data symbols which are related to 'time_t'
or other structures which include 'time_t' (like 'struct stat').
These ROM functions were compiled with sizeof(time_t) == 4.
When compiling with sizeof(time_t) == 8, these functions should be excluded from the build.
*/
__swsetup_r = 0x40001690;
__smakebuf_r = 0x40001954;
__swhatbuf_r = 0x400018f8;
__sfvwrite_r = 0x40001310;
_isatty_r = 0x400078a0;