just use _foo() <-- foo(). In the case of a libpthread that doesn't do
call conversion (such as linuxthreads and our upcoming libpthread), this
is adequate. In the case of libc_r, we still need three names, which are
now _thread_sys_foo() <-- _foo() <-- foo().
Convert all internal libc usage of: aio_suspend(), close(), fsync(), msync(),
nanosleep(), open(), fcntl(), read(), and write() to _foo() instead of foo().
Remove all internal libc usage of: creat(), pause(), sleep(), system(),
tcdrain(), wait(), and waitpid().
Make thread cancellation fully POSIX-compliant.
Suggested by: deischen
points. For library functions, the pattern is __sleep() <--
_libc_sleep() <-- sleep(). The arrows represent weak aliases. For
system calls, the pattern is _read() <-- _libc_read() <-- read().
mode. This addresses a well-known race condition that can cause
servers to hang in accept(). The relevant case is when somebody
connects to the server and then immediately kills the connection
by sending a TCP reset. On the server this causes select to report
a ready condition on the socket, after which the accept call blocks
because there is no longer any pending connection to accept.
In -current there is already a work-around for this in the kernel.
It was merged into -stable some time ago, but then David Greenman
reverted it because it seemed to be causing a socket leak in some
cases. (See uipc_socket.c revision 1.51.2.3.) Hence this userland
fix is needed in -stable, and I plan to merge it into that branch
soon because it fixes a potential DoS attack. It may also be needed
in -current if the suspected socket leak turns out to be real. In
any case, after thinking it over I believe the fix belongs in
userland. An application shouldn't assume that a ready return from
select guarantees that the subsequent I/O operation cannot block.
A lot can happen between the select and the accept.
A similar fix should most likely be applied to the Unix domain
socket transport too.
Submitted by: peter
Reviewed by: jdp
It used to loop back up to the accept() call and block there,
shutting out all other transports until a new connection came in.
Now it returns instead after dropping the connection. That will
take it back to the select() loop where all transports can be
serviced. I intend to MFC this within a day or two since it
fixes a DoS vulnerability.
uses readtcp() to gather data from the network; readtcp() uses select(),
with a timeout of 35 seconds. The problem with this is that if you
connect to a TCP server, send two bytes of data, then just pause, the
server will remain blocked in readtcp() for up to 35 seconds, which is
sort of a long time. If you keep doing this every 35 seconds, you can
keep the server occupied indefinitely.
To fix this, I modified readtcp() (and its cousin, readunix() in svc_unix.c)
to monitor all service transport handles instead of just the current socket.
This allows the server to keep handling new connections that arrive while
readtcp() is running. This prevents one client from potentially monopolizing
a server.
Also, while I was here, I fixed a bug in the timeout calculations. Someone
attempted to adjust the timeout so that if select() returned EINTR and the
loop was restarted, the timeout would be reduced so that rather than waiting
for another 35 seconds, you could never wait for more than 35 seconds total.
Unfortunately, the calculation was wrong, and the timeout could expire much
sooner than 35 seconds.
recently in BUGTRAQ. If a stream oriented transport fails to properly decode
an RPC message header structure where there should be one, it should mark
the stream as dead so that the connection will be dropped.
This concludes tonight's entertainment. Once I'm sure I haven't destroyed
the world with all these changes, I'll import the utilities. Everything
should continue to work as before. If it doesn't let me know.
Special thanks to Mark Murray for running a test 'make world' for me to
shake out the bugs, which, hopefully, I have fixed.
(And there was much rejoicing.)
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
1. Added missing function prototypes.
2. Added missing function return types.
3. Added missing function argument types.
4. Added missing headers for system function prototypes.
5. Corrected format specifier in printf().
6. Added extra parentheses around assignment used as truth value.
7. Added missing "default" cases in switch statements.
8. Added casts for function pointers.
9. Did *not* change int declarations of uid and gid to uid_t/gid_t
because I don't know if that would affect the protocol. Put in
explicit casts to int instead, to make things more obvious.
10. Moved declarations of variables that are only used if YP is
defined inside the '#ifdef YP' conditionals.
1. Added missing function prototypes.
2. Added missing function return types.
3. Added missing function argument types.
4. Added missing headers for system function prototypes.
5. Got rid of "extern int errno" rubbish.
but a commit mail got lost, it's the same as for this commit:
lib/libc/gen confstr.c crypt.c disklabel.c fstab.c getcap.c
getgrent.c getgrouplist.c getpass.c getpwent.c
initgroups.c nlist.c psignal.c pwcache.c setmode.c
sleep.c sysconf.c sysctl.c syslog.c usleep.c
lib/libc/locale none.c read_runemagi.c setlocale.c
lib/libc/net gethostbydns.c getnetbydns.c getnetbynis.c
lib/libc/nls msgcat.c
lib/libc/quad Makefile.inc
lib/libc/regex engine.c regcomp.c regerror.c
Minor cleanup, mostly unused vars and missing #includes.
Limit the number of quad functions we pull in for 'i386'.
I still belive the quad stuff should go back into gcc.
Add compile-time warnings about crypt functions.
