forked from Imagelibrary/rtems
d8a9155512
* include/rtems/libio_.h, libc/chroot.c, libc/privateenv.c:
Private environment and chroot() enhancements and fixes. Comments:
+ privateenv has been modified to let at chroot() to be more
POSIX like Sergei Organov recommended.
+ A task owner lets that rtems_set_private_env() will be
called twice or more times.
+ chroot() can be called without a previous
rtems_set_private_env(); (transpanrently)
+ The second call of rtems_set_private_env() makes a internal
chroot("/") into global imfs_root.
+ chroot() runs like chdir() without a previous chdir("/") with
the global root.
+ The current directory can be in a wrong place like Linux and
many other Unices.
--
-- $Id$
--
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. Its address is stored in notepad[NOTEPAD_LAST].
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.