freebsd-dev

History

marcel 0c624002d4 sigset_t change (part 2 of 5) ----------------------------- The core of the signalling code has been rewritten to operate on the new sigset_t. No methodological changes have been made. Most references to a sigset_t object are through macros (see signalvar.h) to create a level of abstraction and to provide a basis for further improvements. The NSIG constant has not been changed to reflect the maximum number of signals possible. The reason is that it breaks programs (especially shells) which assume that all signals have a non-null name in sys_signame. See src/bin/sh/trap.c for an example. Instead _SIG_MAXSIG has been introduced to hold the maximum signal possible with the new sigset_t. struct sigprop has been moved from signalvar.h to kern_sig.c because a) it is only used there, and b) access must be done though function sigprop(). The latter because the table doesn't holds properties for all signals, but only for the first NSIG signals. signal.h has been reorganized to make reading easier and to add the new and/or modified structures. The "old" structures are moved to signalvar.h to prevent namespace polution. Especially the coda filesystem suffers from the change, because it contained lines like (p->p_sigmask == SIGIO), which is easy to do for integral types, but not for compound types. NOTE: kdump (and port linux_kdump) must be recompiled. Thanks to Garrett Wollman and Daniel Eischen for pressing the importance of changing sigreturn as well.		1999-09-29 15:03:48 +00:00
..
procfs_ctl.c	sigset_t change (part 2 of 5)	1999-09-29 15:03:48 +00:00
procfs_dbregs.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_fpregs.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_map.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_mem.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_note.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_regs.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_rlimit.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_status.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_subr.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_type.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs_vfsops.c	Seperate the export check in VFS_FHTOVP, exports are now checked via	1999-09-11 00:46:08 +00:00
procfs_vnops.c	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
procfs.h	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00
README	$Id$ -> $FreeBSD$	1999-08-28 01:08:13 +00:00

README

saute procfs lyonnais

procfs supports two levels of directory.  the filesystem root
directory contains a representation of the system process table.
this consists of an entry for each active and zombie process, and
an additional entry "curproc" which always represents the process
making the lookup request.

each of the sub-directories contains several files.  these files
are used to control and interrogate processes.  the files implemented
are:

	file	- xxx.  the exec'ed file.

	status  - r/o.  returns process status.

	ctl	- w/o.  sends a control message to the process.
			for example:
				echo hup > /proc/curproc/note
			will send a SIGHUP to the shell.
			whereas
				echo attach > /proc/1293/ctl
			would set up process 1293 for debugging.
			see below for more details.

	mem	- r/w.  virtual memory image of the process.
			parts of the address space are readable
			only if they exist in the target process.
			a more reasonable alternative might be
			to return zero pages instead of an error.
			comments?

	note	- w/o.  writing a string here sends the
			equivalent note to the process.
			[ not implemented. ]

	notepg	- w/o.  the same as note, but sends to all
			members of the process group.
			[ not implemented. ]

	regs	- r/w.	process register set.  this can be read
			or written any time even if the process
			is not stopped.  since the bsd kernel
			is single-processor, this implementation
			will get the "right" register values.
			a multi-proc kernel would need to do some
			synchronisation.

this then looks like:

% ls -li /proc
total 0
   9 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 0
  17 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 1
  89 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 10
  25 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 2
2065 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 257
2481 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 309
 265 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 32
3129 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 390
3209 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 400
3217 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 401
3273 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 408
 393 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 48
 409 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 50
 465 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 57
 481 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 59
 537 dr-xr-xr-x  2 root  kmem   0 Sep 21 15:06 66
 545 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 67
 657 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 81
 665 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 82
 673 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 83
 681 dr-xr-xr-x  2 root  wheel  0 Sep 21 15:06 84
3273 dr-xr-xr-x  2 jsp   staff  0 Sep 21 15:06 curproc
% ls -li /proc/curproc
total 408
3341 --w-------  1 jsp  staff       0 Sep 21 15:06 ctl
1554 -r-xr-xr-x  1 bin  bin     90112 Mar 29 04:52 file
3339 -rw-------  1 jsp  staff  118784 Sep 21 15:06 mem
3343 --w-------  1 jsp  staff       0 Sep 21 15:06 note
3344 --w-------  1 jsp  staff       0 Sep 21 15:06 notepg
3340 -rw-------  1 jsp  staff       0 Sep 21 15:06 regs
3342 -r--r--r--  1 jsp  staff       0 Sep 21 15:06 status
% df /proc/curproc /proc/curproc/file
Filesystem  512-blocks    Used   Avail Capacity  Mounted on
proc                 2       2       0   100%    /proc
/dev/wd0a        16186   13548    1018    93%    /
% cat /proc/curproc/status
cat 446 439 400 81 12,0 ctty 748620684 270000 0 0 0 20000 nochan 11 20 20 20 0 21 117



the basic sequence of commands written to "ctl" would be

	attach		- this stops the target process and
			  arranges for the sending process
			  to become the debug control process
	wait		- wait for the target process to come to
			  a steady state ready for debugging.
	step		- single step, with no signal delivery.
	run		- continue running, with no signal delivery,
			  until next trap or breakpoint.
	<signame>	- deliver signal <signame> and continue running.
	detach		- continue execution of the target process
			  and remove it from control by the debug process

in a normal debugging environment, where the target is fork/exec'd by
the debugger, the debugger should fork and the child should stop itself
(with a self-inflicted SIGSTOP).  the parent should do a "wait" then an
"attach".  as before, the child will hit a breakpoint on the first
instruction in any newly exec'd image.

$FreeBSD$