As far as I can remember the new `dc` argument added to the `mount`
system call is the only API innovation that I imported from Harvey-OS
in the Jehanne's kernel.
It's a great idea of Ronald G. Minnich, introduced at
72777a1fab
Since he didn't amended the copyright statements in Harvey, I forgot
to amend it here.
Sorry, my fault.
I'm very grateful to Charles Forsyth for creating most of Jehanne's kernel
and to 9front's guys for all the code and ideas they freely share.
Here I make their copyrights explicit as they had been erroneusly omitted
or messed up before. Sorry.
While sending Tflush after a wakeup, we might call sleep.
Since the awake was not yet consumed, the new sleep was interrupted
causing a new Tflush, in an infinite loop that consumes all tags.
After sending the "clone" request to /proc/$pid/ns, the current process
will be moved to the working directory of $pid.
Otherwise the current process could still access the file and folders
on the service providing its dot, even if such service was not visible to $pid.
Also, keeping the original working directory means that the 'cd' line of the
current process's ns file would be different from that of $pid: the two ns
files must match since the command asked for a "clone".
See also https://marc.info/?l=9fans&m=150893734909969&w=2
Calling resrcwait in awake_gc_proc (that is called from pexit and thus
from sys_exits) means that we have to ignore errors that could cause
the syscall to return.
The funny part here was that one single test for newlib showed the
issue by faulting in a note handler AFTER completing with success:
/arch/amd64/qa/lib/newlib/sigchld/213-sigqueue
The fact was that in the executable, the function notifier() was
located just after the exits() function, whose last line was a call
to _exits().
Thus, when the _exits returned, the notifier() code was executed.
In _procfdprint print additional informations in the second column:
E is printed if the file was open with OCEXEC flag
D is printed if the file was open with ORCLOSE flag
Example output:
3 rE 9 46 (0000000000000001 0 00) 8192 13 /dev/cons
Any process X can get a new copy of the namespace of a target
process Y by writing the string "clone" to the ns file of Y.
The same user must own both processes.
The process writing the ns file must be allowed to mount.
The Pgrp of the calling process is then replaced with a new copy of
the Pgrp of the target process.
After the operation, any change done by X to its own namespace does
not affect Y. Also, if mount was forbidden for Y, it will also be
forbidden for X after the clone.
The img_get macro used to subtract 1 to the argument provided before
computing the porinter to the image. I can't remember why it did so.
However the expression was wrong.
Coverity found the issue:
Operands don't affect result (CONSTANT_EXPRESSION_RESULT)
CID: 155616, 155606, 155598, 155597, 155596, 155587,
155580, 155578, 155577, 155576, 155568, 155566
Simply removing the subtraction seems the obvious fix.
This large commit address several issues
- removed 386 directory: Jehanne is 64bit only
- simplified kernel options management
- rewritten boot process
- ported memory related stuff from 9front's 9/pc64
- removed devacpi
- removed old code
- deep refactor of awake syscall
- removed MCACHE support for mount
- fix libc's setjmp/longjmp
This commit introduce a special rendezvous point at (void*)~0 that
cannot be reached by any process, since it's not added to the
rendezvous group.
This turns the rendezvous syscall to a cheap way to block until
either a note or a wakeup from awake(2) occurs.
This new feature is used in libc's sleep: the test qa/kern/fork_chain
has shown that using a stack address as rendezvous point is not safe enougth
for sleep, since two different process forked from the same function can
call sleep with the same base pointer. This lead the wakeup variable in
jehanne_sleep to have the same address on both process.
TODO add a test that show this behaviour in the old code.
This way sleep() knows that it should not interrupt the process
to serve awake().
Also rename Proc.insyscall to Proc.inkernel since that's the meaning
of the flag, which is only read to serve awake()'s mechanics and
to accounttime(). Indeed faultAmd64 was setting insyscall to 1.
The "write on closed pipe" note should be posted only
if the write occurred on a closed pipe.
Before this fix, on any interrupt caused the note to be sent,
despite the pipe being open and fully working.
Awake can now interrupt several blocking syscalls (even
during note handling).
Among others, it can interrupt await, pread and pwrite.
It cannot interrupt several others for different reasons:
- awake cannot be interrupted by awake;
- syscalls like remove and create can be used for kernel comunication
and it would be hard to know if the effect occurred in the
receiving fs if they were interrupted;
- other syscalls do not need awake since they just provide access
to kernel infos (eg seek or fd2path)
NOTE: awakes registered before a note cannot occur during the note
handling and will be deferred till the next call to noted.
With this commit all functions declared in libc.h have been renamed
with the "jehanne_" prefix. This is done for several reason:
- it removes conflicts during symbol resolution when linking
standard C libraries like newlib or musl
- it allows programs depending on a standard C library to directly
link to a library depending on our non standard libc (eg libsec).
To ease transiction two files are provided:
- sys/include/lib9.h that can be included instead of <libc.h> to use
the old names (via a simple set of macros)
- sys/src/lib/c/lib9.c that can be compiled with a program where the
macro provided by lib9.h are too dumb (see for example rc or grep).
In the kernel port/lib.h has been modified accordingly and some of
the functions it directly provides has been renamed too (eg malloc
in qmalloc.c and print in devcons.c).
Giacomo Tesio