and PID allocation MP-safe. A new process state is added: SDEAD. This
state indicates that a process is dead, but not yet a zombie (has not
yet been processed by the process reaper).
SDEAD processes exist on both the zombproc list (via p_list) and deadproc
(via p_hash; the proc has been removed from the pidhash earlier in the exit
path). When the reaper deals with a process, it changes the state to
SZOMB, so that wait4 can process it.
Add a P_ZOMBIE() macro, which treats a proc in SZOMB or SDEAD as a zombie,
and update various parts of the kernel to reflect the new state.
array of ARG_MAX size. ARG_MAX is currently 256k, which causes a rather
serious stack overflow (kernel stacks are not very large, usually 8k).
Fixes memory corruption problems observed after accessig /proc/1/cmdline
during tests. Problem in my case manifested itself as massive lossage
in ffs_sync(), resulting in a crash, and sometimes, pooched file systems.
XXX This could, and probably should, be rewritten to use a much smaller
temporary buffer, and a loop around uiomove().
- Don't error out on P_SYSTEM or SZOMB processes; instead, do what ps(1)
would do, i.e. the p_comm in parenthesis.
- Use uvm_io() (or procfs_rwmem() if !UVM) to read the target process's
psstrings and argument vector. Using copyin() is problematic, because
it operates on the current processes! That is, the old code would
always get the `cmdline' of the process reading the file, not that of
the target process.
thorpej