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.
Cases
This is a list of cases to consider when implementing a file system:
+ Given a tree of this form:
a ----- b
/
c
Where a and b are directories and c is a link to directory b. Consider
this sequence:
- rmdir a/b
- mknod c/b/x
- unlink c
TODO
newlib 1.8.0 has the wrong prototype for at least read() and write().
There should be a "eat it" stub for all system calls which are
available to make filling out an operations table easier.
See device_lseek() for an example of where this would be nice.
Fix strerror() so it prints all error numbers.
Check the node allocation coment in the fchdir call.
64fe53a855