esp-idf/components/esp_rom/esp32/ld/esp32.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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/* These are the newlib functions and the .bss/.data symbols necessary for these functions present in ESP32 ROM.
They should not be used when you need to solve the Y2K38 problem.
Because these functions were compiled with 32-bit width for the time_t structure.
*/
asctime = 0x40059588;
asctime_r = 0x40000ec8;
ctime = 0x400595b0;
ctime_r = 0x400595c4;
__gettzinfo = 0x40001fcc;
__get_current_time_locale = 0x40001834;
gmtime = 0x40059848;
gmtime_r = 0x40059868;
localtime = 0x400595dc;
localtime_r = 0x400595fc;
mktime = 0x4005a5e8;
strftime = 0x40059ab4;
time = 0x40001844;
__time_load_locale = 0x4000183c;
tzset = 0x40001a1c;
_tzset_r = 0x40001a28;
__tzcalc_limits = 0x400018a0;
__tz_lock = 0x40001a04;
__tz_unlock = 0x40001a10;
/* The .bss/.data symbols necessary for these functions */
_timezone = 0x3ffae0a0;
_tzname = 0x3ffae030;
_daylight = 0x3ffae0a4;
__month_lengths = 0x3ff9609c;
/* These functions don't use time_t, but use other structures which include time_t.
* For example, 'struct stat' contains time_t.
*/
_isatty_r = 0x40000ea0;
__sfvwrite_r = 0x4005893c;
__smakebuf_r = 0x40059108;
__srefill_r = 0x400593d4;
__swsetup_r = 0x40058cc8;