- We now serialize the file descriptor table when spawning / executing
processes on Windows. This means you can now inherit more stuff than
just standard i/o. It's needed by bash, which duplicates the console
to file descriptor #255. We also now do a better job serializing the
environment variables, so you're less likely to encounter E2BIG when
using your bash shell. We also no longer coerce environ to uppercase
- execve() on Windows now remotely controls its parent process to make
them spawn a replacement for itself. Then it'll be able to terminate
immediately once the spawn succeeds, without having to linger around
for the lifetime as a shell process for proxying the exit code. When
process worker thread running in the parent sees the child die, it's
given a handle to the new child, to replace it in the process table.
- execve() and posix_spawn() on Windows will now provide CreateProcess
an explicit handle list. This allows us to remove handle locks which
enables better fork/spawn concurrency, with seriously correct thread
safety. Other codebases like Go use the same technique. On the other
hand fork() still favors the conventional WIN32 inheritence approach
which can be a little bit messy, but is *controlled* by guaranteeing
perfectly clean slates at both the spawning and execution boundaries
- sigset_t is now 64 bits. Having it be 128 bits was a mistake because
there's no reason to use that and it's only supported by FreeBSD. By
using the system word size, signal mask manipulation on Windows goes
very fast. Furthermore @asyncsignalsafe funcs have been rewritten on
Windows to take advantage of signal masking, now that it's much more
pleasant to use.
- All the overlapped i/o code on Windows has been rewritten for pretty
good signal and cancelation safety. We're now able to ensure overlap
data structures are cleaned up so long as you don't longjmp() out of
out of a signal handler that interrupted an i/o operation. Latencies
are also improved thanks to the removal of lots of "busy wait" code.
Waits should be optimal for everything except poll(), which shall be
the last and final demon we slay in the win32 i/o horror show.
- getrusage() on Windows is now able to report RUSAGE_CHILDREN as well
as RUSAGE_SELF, thanks to aggregation in the process manager thread.
- Improved async signal safety of read() particularly for longjmp()
- Started adding cancel cleanup handlers for locks / etc on Windows
- Make /dev/tty work better particularly for uses like `foo | less`
- Eagerly read console input into a linked list, so poll can signal
- Fix some libc definitional bugs, which configure scripts detected
- Every unit test now passes on Apple Silicon. The final piece of this
puzzle was porting our POSIX threads cancelation support, since that
works differently on ARM64 XNU vs. AMD64. Our semaphore support on
Apple Silicon is also superior now compared to AMD64, thanks to the
grand central dispatch library which lets *NSYNC locks go faster.
- The Cosmopolitan runtime is now more stable, particularly on Windows.
To do this, thread local storage is mandatory at all runtime levels,
and the innermost packages of the C library is no longer being built
using ASAN. TLS is being bootstrapped with a 128-byte TIB during the
process startup phase, and then later on the runtime re-allocates it
either statically or dynamically to support code using _Thread_local.
fork() and execve() now do a better job cooperating with threads. We
can now check how much stack memory is left in the process or thread
when functions like kprintf() / execve() etc. call alloca(), so that
ENOMEM can be raised, reduce a buffer size, or just print a warning.
- POSIX signal emulation is now implemented the same way kernels do it
with pthread_kill() and raise(). Any thread can interrupt any other
thread, regardless of what it's doing. If it's blocked on read/write
then the killer thread will cancel its i/o operation so that EINTR can
be returned in the mark thread immediately. If it's doing a tight CPU
bound operation, then that's also interrupted by the signal delivery.
Signal delivery works now by suspending a thread and pushing context
data structures onto its stack, and redirecting its execution to a
trampoline function, which calls SetThreadContext(GetCurrentThread())
when it's done.
- We're now doing a better job managing locks and handles. On NetBSD we
now close semaphore file descriptors in forked children. Semaphores on
Windows can now be canceled immediately, which means mutexes/condition
variables will now go faster. Apple Silicon semaphores can be canceled
too. We're now using Apple's pthread_yield() funciton. Apple _nocancel
syscalls are now used on XNU when appropriate to ensure pthread_cancel
requests aren't lost. The MbedTLS library has been updated to support
POSIX thread cancelations. See tool/build/runitd.c for an example of
how it can be used for production multi-threaded tls servers. Handles
on Windows now leak less often across processes. All i/o operations on
Windows are now overlapped, which means file pointers can no longer be
inherited across dup() and fork() for the time being.
- We now spawn a thread on Windows to deliver SIGCHLD and wakeup wait4()
which means, for example, that posix_spawn() now goes 3x faster. POSIX
spawn is also now more correct. Like Musl, it's now able to report the
failure code of execve() via a pipe although our approach favors using
shared memory to do that on systems that have a true vfork() function.
- We now spawn a thread to deliver SIGALRM to threads when setitimer()
is used. This enables the most precise wakeups the OS makes possible.
- The Cosmopolitan runtime now uses less memory. On NetBSD for example,
it turned out the kernel would actually commit the PT_GNU_STACK size
which caused RSS to be 6mb for every process. Now it's down to ~4kb.
On Apple Silicon, we reduce the mandatory upstream thread size to the
smallest possible size to reduce the memory overhead of Cosmo threads.
The examples directory has a program called greenbean which can spawn
a web server on Linux with 10,000 worker threads and have the memory
usage of the process be ~77mb. The 1024 byte overhead of POSIX-style
thread-local storage is now optional; it won't be allocated until the
pthread_setspecific/getspecific functions are called. On Windows, the
threads that get spawned which are internal to the libc implementation
use reserve rather than commit memory, which shaves a few hundred kb.
- sigaltstack() is now supported on Windows, however it's currently not
able to be used to handle stack overflows, since crash signals are
still generated by WIN32. However the crash handler will still switch
to the alt stack, which is helpful in environments with tiny threads.
- Test binaries are now smaller. Many of the mandatory dependencies of
the test runner have been removed. This ensures many programs can do a
better job only linking the the thing they're testing. This caused the
test binaries for LIBC_FMT for example, to decrease from 200kb to 50kb
- long double is no longer used in the implementation details of libc,
except in the APIs that define it. The old code that used long double
for time (instead of struct timespec) has now been thoroughly removed.
- ShowCrashReports() is now much tinier in MODE=tiny. Instead of doing
backtraces itself, it'll just print a command you can run on the shell
using our new `cosmoaddr2line` program to view the backtrace.
- Crash report signal handling now works in a much better way. Instead
of terminating the process, it now relies on SA_RESETHAND so that the
default SIG_IGN behavior can terminate the process if necessary.
- Our pledge() functionality has now been fully ported to AARCH64 Linux.
The new asynchronous signal delivery technique is now also being used
for tkill(), raise(), etc. Many subtle issues have been addresesd. We
now signal handling on Windows that's remarkably similar to the POSIX
behaviors. However that's just across threads. We're lacking a way to
have the signal semantics work well, across multiple WIN32 processes.
This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.
- Get SIGWINCH working again on the New Technology
- Correctly handle O_NOFOLLOW in open() on Windows
- Implement synthetic umask() functionality on Windows
- Do a better job managing file execute access on Windows
- Fill in `st_uid` and `st_gid` with username hash on Windows
- Munge UNICODE control pictures into control codes on Windows
- Do a better job ensuring Windows console settings are restored
- Introduce KPRINTF_LOG environment variable to log kprintf to a file
This change makes posix_spawn_test no longer flaky on Windows, by (1)
fixing a race condition in wait(), and (2) removing a misguided vfork
implementation which was letting Windows bypass pthread_atfork().
- Fix unused local variable errors
- Remove yoinks from sigaction() header
- Add nox87 and aarch64 to github actions
- Fix cosmocc -fportcosmo in linking mode
- It's now possible to build `make m=llvm o/llvm/libc`
- Exhaustively document cancellation points
- Rename SIGCANCEL to SIGTHR just like BSDs
- Further improve POSIX thread cancellations
- Ensure asynchronous cancellations work correctly
- Elevate the quality of getrandom() and getentropy()
- Make futexes cancel correctly on OpenBSD 6.x and 7.x
- Add reboot.com and shutdown.com to examples directory
- Remove underscore prefix from awesome timespec_*() APIs
- Create assertions that help verify our cancellation points
- Remove bad timespec APIs (cmp generalizes eq/ne/gt/gte/lt/lte)
This change makes some miracle modifications to the System Five system
call support, which lets us have safe, correct, and atomic handling of
thread cancellations. It all turned out to be cheaper than anticipated
because it wasn't necessary to modify the system call veneers. We were
able to encode the cancellability of each system call into the magnums
found in libc/sysv/syscalls.sh. Since cancellations are so waq, we are
also supporting a lovely Musl Libc mask feature for raising ECANCELED.
This change also found a few POSIX compliance bugs with errnos. Another
bug was discovered where, on Windows, pread() and pwrite() could modify
the file position in cases where ReadFile() returned an error e.g. when
seeking past the end of file. We also have more tests!
This makes breaking changes to add underscores to many non-standard
function names provided by the c library. MODE=tiny is now tinier and
we now use smaller locks that are better for tiny apps in this mode.
Some headers have been renamed to be in the same folder as the build
package, so it'll be easier to know which build dependency is needed.
Certain old misguided interfaces have been removed. Intel intrinsics
headers are now listed in libc/isystem (but not in the amalgamation)
to help further improve open source compatibility. Header complexity
has also been reduced. Lastly, more shell scripts are now available.
- Introduce __assert_disable global
- Improve strsignal() thread safety
- Make system call tracing thread safe
- Fix SO_RCVTIMEO / SO_SNDTIMEO on Windows
- Refactor DescribeFoo() functions into one place
- Fix fork() on Windows when TLS and MAP_STACK exist
- Round upwards in setsockopt(SO_RCVTIMEO) on Windows
- Disable futexes on OpenBSD which seem extremely broken
- Implement a better kludge for monotonic time on Windows
- Get threads working on NetBSD
- Get threads working on OpenBSD
- Fix Emacs config for Emacs v28
- Improve --strace logging of sigset_t
- Improve --strace logging of struct stat
- Improve memory safety of DescribeThing functions
- Refactor auto stack allocation into LIBC_RUNTIME
- Introduce shell.com example which works on Windows
- Refactor __strace_thing into DescribeThing functions
- Document the CHECK macros and improve them in NDEBUG mode
- Rewrite MAP_STACK so it uses FreeBSD behavior across platforms
- Deprecate and discourage the use of MAP_GROWSDOWN (it's weird)
This change makes further effort towards improving our poll()
implementation on the New Technology. The stdin worker didn't work out
so well for Python so it's not being used for now. System call tracing
with the --strace flag should now be less noisy now on Windows unless
you modify the strace.internal.h defines to turn on some optional ones
that are most useful for debugging the system call wrappers.
- Fix bugs in kDos2Errno definition
- malloc() should now be thread safe
- Fix bug in rollup.com header generator
- Fix open(O_APPEND) on the New Technology
- Fix select() on the New Technology and test it
- Work towards refactoring i/o for thread safety
- Socket reads and writes on NT now poll for signals
- Work towards i/o completion ports on the New Technology
- Make read() and write() intermittently check for signals
- Blinkenlights keyboard i/o so much better on NT w/ poll()
- You can now poll() files and sockets at the same time on NT
- Fix bug in appendr() that manifests with dlmalloc footers off
- Introduce fast spinlock API
- Double rand64() perf w/ spinlock
- Improve raise() on New Technology
- Support gettid() across platforms
- Implement SA_NODEFER on New Technology
- Move the lock intrinsics into LIBC_INTRIN
- Make SIGTRAP recoverable on New Technology
- Block SIGCHLD in wait4() on New Technology
- Add threading prototypes for XNU and FreeBSD
- Rewrite abort() fixing its minor bugs on XNU/NT
- Shave down a lot of the content in libc/bits/bits.h
- Let signal handlers modify CPU registers on New Technology
- Fix sigsuspend() on XNU
- Fix strsignal() on non-Linux
- Add unit tests for strsignal()
- Add unit tests for setitimer()
- Add unit tests for sigsuspend()
- Rewrite setitimer() for New Technology
- Rewrite nanosleep() for New Technology
- Polyfill SIGALRM on the New Technology
- select(0,0,0,0) on NT now calls pause()
- Remove some NTDLL calls that aren't needed
- Polyfill SA_NOCLDWAIT on the New Technology
- Polyfill SA_RESETHAND on the New Technology
- Polyfill sigprocmask() on the New Technology
- Polyfill SIGCHLD+SIG_IGN on the New Technology
- Polyfill SA_RESTART masking on the New Technology
- Deliver console signals from main thread on New Technology
- Document SA_RESTART behavior w/ @sarestartable / @norestart
- System call trace in MODE=dbg now prints inherited FDs and signal mask
This is similar to the --ftrace (c function call trace) flag, except
it's less noisy since it only logs system calls to stderr. Having this
flag is valuable because (1) system call tracing tells us a lot about
the behavior of complex programs and (2) it's usually very hard to get
system call tracing on various operating systems, e.g. strace, ktrace,
dtruss, truss, nttrace, etc. Especially on Apple platforms where even
with the special boot trick, debuggers still aren't guaranteed to work.
make -j8 o//examples
o//examples/hello.com --strace
This is enabled by default in MODE=, MODE=opt, and MODE=dbg. In MODE=dbg
extra information will be printed.
make -j8 MODE=dbg o/dbg/examples
o/dbg/examples/hello.com --strace |& less
This change also changes:
- Rename IsText() → _istext()
- Rename IsUtf8() → _isutf8()
- Fix madvise() on Windows NT
- Fix empty string case of inet_ntop()
- vfork() wrapper now saves and restores errno
- Update xsigaction() to yoink syscall support
The ZIP filesystem has a breaking change. You now need to use /zip/ to
open() / opendir() / etc. assets within the ZIP structure of your APE
binary, instead of the previous convention of using zip: or zip! URIs.
This is needed because Python likes to use absolute paths, and having
ZIP paths encoded like URIs simply broke too many things.
Many more system calls have been updated to be able to operate on ZIP
files and file descriptors. In particular fcntl() and ioctl() since
Python would do things like ask if a ZIP file is a terminal and get
confused when the old implementation mistakenly said yes, because the
fastest way to guarantee native file descriptors is to dup(2). This
change also improves the async signal safety of zipos and ensures it
doesn't maintain any open file descriptors beyond that which the user
has opened.
This change makes a lot of progress towards adding magic numbers that
are specific to platforms other than Linux. The philosophy here is that,
if you use an operating system like FreeBSD, then you should be able to
take advantage of FreeBSD exclusive features, even if we don't polyfill
them on other platforms. For example, you can now open() a file with the
O_VERIFY flag. If your program runs on other platforms, then Cosmo will
automatically set O_VERIFY to zero. This lets you safely use it without
the need for #ifdef or ifstatements which detract from readability.
One of the blindspots of the ASAN memory hardening we use to offer Rust
like assurances has always been that memory passed to the kernel via
system calls (e.g. writev) can't be checked automatically since the
kernel wasn't built with MODE=asan. This change makes more progress
ensuring that each system call will verify the soundness of memory
before it's passed to the kernel. The code for doing these checks is
fast, particularly for buffers, where it can verify 64 bytes a cycle.
- Correct O_LOOP definition on NT
- Introduce program_executable_name
- Add ASAN guards to more system calls
- Improve termios compatibility with BSDs
- Fix bug in Windows auxiliary value encoding
- Add BSD and XNU specific errnos and open flags
- Add check to ensure build doesn't talk to internet
I wanted a tiny scriptable meltdown proof way to run userspace programs
and visualize how program execution impacts memory. It helps to explain
how things like Actually Portable Executable works. It can show you how
the GCC generated code is going about manipulating matrices and more. I
didn't feel fully comfortable with Qemu and Bochs because I'm not smart
enough to understand them. I wanted something like gVisor but with much
stronger levels of assurances. I wanted a single binary that'll run, on
all major operating systems with an embedded GPL barrier ZIP filesystem
that is tiny enough to transpile to JavaScript and run in browsers too.
https://justine.storage.googleapis.com/emulator625.mp4
