updates an environment variable of a running process

export_process

# updates an environment variable of a running process (needs sudo)
# example: sudo export_pid <variable=value> <pid>

export_process(){
  script=/tmp/.gdb.$2
  echo -e "attach $2\ncall putenv (\"$1\")\ndetach\n" > $script
  gdb -q -batch -x $script &>/dev/null
  rm $script
}

If I attach gdb to the current shell and try to set env variable it remains the same(or doesn't exist):

$] sudo gdb -p $$
(gdb) call putenv("TEST=1234")
$1 = 0
(gdb) call (char*) getenv("TEST")
$2 = 0x0
(gdb) detach
(gdb) quit
$] echo "TEST=$TEST"
TEST=

I've found out that putenv doesn't work, but setenv does:

$] sudo gdb -p $$
(gdb) call (int) setenv("TEST", "1234", 1)
$1 = 0
(gdb) call (char*) getenv("TEST")
$2 = 0x55f19ff5edc0 "1234"
(gdb) detach
(gdb) quit
$] echo "TEST=$TEST"
TEST=1234

According to the documentation

int setenv(const char *envname,
           const char *envval,
           int overwrite);