This patch adds the ability for termios to send SIGINTR on receipt
of VINTR and SIGQUIT for VKILL and return -1/EINTR from read() on
a termios channel. Importantly, this patch does not alter the default
behavior or force POSIX signal code in just because termios is used.
The application must explicitly enable the POSIX behavior of generating
a signal upon receipt of these characters. This is discussed in the
POSIX standard:
https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap11.html
Closes#3800.
--
Overview of newlib support (newlib is from CYGNUS)
Each task can have its own libc state including:
open stdio files
strtok
multi precision arithmetic state
etc.
This is implemented by a reentrancy data structure for each task.
When a task is "started" (in RTEMS sense) the reentrancy structure
is allocated.
When task is switched to, the value of global variable _impure_ptr
is changed to the value of the new tasks reentrancy structure.
When a task is deleted
atexit() processing (for that task) happens
task's stdio buffers are flushed
When exit(3) is called
calling task's atexit processing done
global libc state atexit processing done
(this will include any atexit routines installed by drivers)
executive is shutdown
causes a context switch back to bsp land
NOTE:
libc extension are installed by bsp_libc_init()
iff we are using clock interrupts.
This hack is necessary to allow the tmtests to avoid
timing the extensions.
667501a314