Sometimes we need to interact with code that wasn't compiled using
`-fno-omit-frame-pointer`. For example, if a function pointer gets
passed and called by a foreign function, linked by cosmo_dlopen().
Function call tracing will now detect backtrace pointer corruption
and simply reduce the indentation level back to zero, as a result.
This change upgrades to GCC 12.3 and GNU binutils 2.42. The GNU linker
appears to have changed things so that only a single de-duplicated str
table is present in the binary, and it gets placed wherever the linker
wants, regardless of what the linker script says. To cope with that we
need to stop using .ident to embed licenses. As such, this change does
significant work to revamp how third party licenses are defined in the
codebase, using `.section .notice,"aR",@progbits`.
This new GCC 12.3 toolchain has support for GNU indirect functions. It
lets us support __target_clones__ for the first time. This is used for
optimizing the performance of libc string functions such as strlen and
friends so far on x86, by ensuring AVX systems favor a second codepath
that uses VEX encoding. It shaves some latency off certain operations.
It's a useful feature to have for scientific computing for the reasons
explained by the test/libcxx/openmp_test.cc example which compiles for
fifteen different microarchitectures. Thanks to the upgrades, it's now
also possible to use newer instruction sets, such as AVX512FP16, VNNI.
Cosmo now uses the %gs register on x86 by default for TLS. Doing it is
helpful for any program that links `cosmo_dlopen()`. Such programs had
to recompile their binaries at startup to change the TLS instructions.
That's not great, since it means every page in the executable needs to
be faulted. The work of rewriting TLS-related x86 opcodes, is moved to
fixupobj.com instead. This is great news for MacOS x86 users, since we
previously needed to morph the binary every time for that platform but
now that's no longer necessary. The only platforms where we need fixup
of TLS x86 opcodes at runtime are now Windows, OpenBSD, and NetBSD. On
Windows we morph TLS to point deeper into the TIB, based on a TlsAlloc
assignment, and on OpenBSD/NetBSD we morph %gs back into %fs since the
kernels do not allow us to specify a value for the %gs register.
OpenBSD users are now required to use APE Loader to run Cosmo binaries
and assimilation is no longer possible. OpenBSD kernel needs to change
to allow programs to specify a value for the %gs register, or it needs
to stop marking executable pages loaded by the kernel as mimmutable().
This release fixes __constructor__, .ctor, .init_array, and lastly the
.preinit_array so they behave the exact same way as glibc.
We no longer use hex constants to define math.h symbols like M_PI.
- Introduce portable sched_getcpu() api
- Support GCC's __target_clones__ feature
- Make fma() go faster on x86 in default mode
- Remove some asan checks from core libraries
- WinMain() now ensures $HOME and $USER are defined
1. `libc/isystem/complex.h` (included when you do `#include <complex.h>`)
defines `_COMPLEX_H`, and then proceeds to include `libc/complex.h`,
which contains the actual complex-related declarations. However, they
are *also* guarded by `_COMPLEX_H` and hence effectively ignored.
Fix this by changing `_COMPLEX_H` to `COSMOPOLITAN_LIBC_COMPLEX_H_`,
which is consistent with what the other headers (such as `math.h`) do.
2. Cosmopolitan could only support IPv4 multicast requests for sockets,
since a declaration for `struct ipv6_mreq` was missing. Add support
for IPv6, too, by adding the missing declaration.
- Let OpenMP be usable via cosmocc
- Let libunwind be usable via cosmocc
- Make X86_HAVE(AVXVNNI) work correctly
- Avoid using MAP_GROWSDOWN on qemu-aarch64
- Introduce in6addr_any and in6addr_loopback
- Have thread stacks use MAP_GROWSDOWN by default
- Ask OpenMP to not use filesystem to manage threads
- Make NI_MAXHOST and NI_MAXSERV available w/o _GNU_SOURCE
We recently broke MODE=dbg support when we added C++ exception support.
This change adds the missing UBSAN interfaces, needed to get it working
again. Some of the ASAN checking in the SJLJ guts needed to be disabled
since I doubt anyone's combined the two features until now.
Embedding Blink builds in Cosmo executables was a failed experiment. It
turned out to be easier than expected to let the mono repo have support
for multiple architectures. Blink still works great; it's supported and
recommended; just please use it as a separate program. For example, you
can use Blink to run Cosmo binaries on architectures like i486 / s390x.
If you install qemu-user from apt then glibc links a lot of address
space bloat that causes pthread_create() to ENOMEM (a.k.a. EAGAIN).
Boosting the virtual memory quota from 512m to 2048m will hopefully
future proof the build for the future, as Linux distros get fatter.
Please note this only applies to MODE=aarch64 on x86_64 builds when
you're using QEMU from Debian/Ubuntu rather than installing the one
cosmo provides in third_party/qemu/qemu-aarch64.gz. This change may
also be useful to people who are using the host compiler toolchain.
- `__cxa_*` runtime functions are expected to be in the `abi` namespace,
which is currently an alias for `__cxxabiv1`.
- Rely on the header provided by `libcxxabi` for functions that we do
not implement ourselves anymore.
This will help C++ code that uses exceptions to be tinier. For example,
this change shaves away 1000 lines of assembly code from LLVM's libcxx,
which is 0.7% of all assembly instructions in the entire library.
We now store values in jmp_buf where the compiler wants them to be. This
fixes code that calls __builtin_setjmp() and __builtin_longjmp() such as
libunwind. All libcxxabi tests are now passing on ARM64.
See #1076
Renaming gc() to _gc() was a mistake since the better thing to do is put
it behind the _COSMO_SOURCE macro. We need this change because I haven't
wanted to use my amazing garbage collector ever since we renamed it. You
now need to define _COSMO_SOURCE yourself when using amalgamation header
and cosmocc users need to pass the -mcosmo flag to get the gc() function
Some other issues relating to cancelation have been fixed along the way.
We're also now putting cosmocc in a folder named `.cosmocc` so it can be
more safely excluded by grep --exclude-dir=.cosmocc --exclude-dir=o etc.
* third_party: Add libcxxabi
Added libcxxabi from LLVM 17.0.6
The library implements the Itanium C++ exception handling ABI.
* third_party/libcxxabi: Enable __cxa_thread_atexit
Enable `__cxa_thread_atexit` from libcxxabi.
`__cxa_thread_atexit_impl` is still implemented by the cosmo libc.
The original `__cxa_thread_atexit` has been removed.
* third_party/libcxx: Build with exceptions
Build libcxx with exceptions enabled.
- Removed `_LIBCPP_NO_EXCEPTIONS` from `__config`.
- Switched the exception implementation to `libcxxabi`. These two files
are taken from the same `libcxx` version as mentioned in `README.cosmo`.
- Removed `new_handler_fallback` in favor of `libcxxabi` implementation.
- Enable `-fexceptions` and `-frtti` for `libcxx`.
- Removed `THIRD_PARTY_LIBCXX` dependency from `libcxxabi` and
`libunwind`. These libraries do not use any runtime `libcxx` functions,
just headers.
* libc: Remove remaining redundant cxa functions
- `__cxa_pure_virtual` in `libcxxabi` is also a stub similar to the
existing one.
- `__cxa_guard_*` from `libcxxabi` is used instead of the ones from
Android.
Now there should be no more duplicate implementations.
`__cxa_thread_atexit_impl`, `__cxa_atexit`, and related supporting
functions, are still left to other libraries as in `libcxxabi`.
`libcxxabi` is also now added to `cosmopolitan.a` to make up for the
removed functions.
Affected in-tree libraries (`third_party/double-conversion`) have been
updated.
The AMD HIP SDK for Linux ships prebuilt DSOs with an RWX PT_GNU_STACK
since old versions of GCC made it nearly impossible to build artifacts
where that wasn't the case, however modern glibc systems will flat out
refuse to link RWX DSOs from an execuatble that uses PT_GNU_STACK = RW
The cosmo_dlsym() function now returns the raw function address. You
need to call cosmo_dltramp() on the result, to make it safe to call.
This change is important, because cosmo_dltramp() magic can't always
work; for some tricky functions, you need to translate ABIs by hand.
Now we do them for assimilated binaries (except on OpenBSD or XNU
non-Silicon), for XnuSilicon, and for binaries with the preserve-
argv[0] auxv flag set. We check whether to pass the argv[0] value
at the test site rather than the Child site. We move a lot of the
test initialization into Child in the non-child case, in order to
get at the pre-init value of `__program_executable_name`. Finally,
we print out info about what we are skipping.
If cosmo_dlopen() is linked on AMD64 then the runtime will switch to
using %gs for thread-local storage. This eliminates the need for the
imported symbol trampoline. It's now safer to pass function pointers
back and forth with imported libraries. Your program gets recompiled
at runtime to make it happen and the overhead is a few milliseconds.
The toolchain will now be downloaded going forward from multiple pinned
URLs which have shasums. Either wget or curl must be installed.
This change unblocks #1053
Our dynamic linking implementation is now able to support functions with
dozens of parameters. In addition to having extra integral arguments you
can now pass vector registers using intrinsic types. Lastly, you can now
return multiple values, which is useful for functions returning structs.
* Reorder Launch arguments, pass aarch64 os
Third and fourth arguments are now identical between cosmo and Launch.
By passing sp as argument 4, we save a bit of register juggling.
Fourth argument (os) is now always passed by the loader on aarch64. It
is not yet processed by cosmo. Pushing this change separately, as the
cosmo side turns out to be somewhat more involved.
* cosmo2 receives os from loader
FreeBSD aarch64 now traps early rather than pretending to be Linux.
o/aarch64/examples/env.com still works on Linux and Xnu.
Now that our socket system call polyfills are good enough to support
Musl's DNS library we should be using that rather than the barebones
domain name system implementation we rolled on our own. There's many
benefits to making this change. So many, that I myself wouldn't feel
qualified to enumerate them all. The Musl DNS code had to be changed
in order to support Windows of course, which looks very solid so far
Missed this when changing the code back to be like the old version.
com is now a parameter.
The only plausible way to trigger this would be to pass a loader
pathname close to MAX_PATH characters long, and then remove that
path prior to the first sys_faccessat.
This implements proposals 1 and 2a from this gist:
https://gist.github.com/mrdomino/2222cab61715fd527e82e036ba4156b1
The only reason to use realpath from the loader was to try to prevent a
TOCTOU between the loader and the binary. But this is only a real issue
in set-id contexts, and in those cases there is already a canonical way
to do it: `/dev/fd`, passed by the kernel to the loader, so all we have
to do is pass that along to the binary.
Aside from realpath, there is no reason to absolutize the path we supply
to the binary, since it can call `getcwd` as well as we can, and on non-
M1 the binary is in a much better position to make that call.
Since we no longer absolutize the path, the binary does need to do this,
so we make its argv-parsing code generic and apply that to the different
possible places the path could come from. This means that `_` is finally
usable as a relative path, as a nice side benefit.
The M1 realpath code had a significant bug - it uses the wrong offset to
truncate the `.ape` in the `$prog.ape` case.
This PR also fixes a regression in `ape $progname` out of `$PATH` on the
two BSDs (Free and Net) that did not implement `RealPath`.
Fixes a regression in GetProgramExecutableName on Linux against old
loaders. In the loader case, /proc/self/exe gives the loader's path.
We tried to detect this by checking for `/usr/bin/ape`. But that is
only one of the possible places the loader could be.
Somehow or another, I previously had missed `BUILD.mk` files.
In the process I found a few straggler cases where the modeline was
different from the file, including one very involved manual fix where a
file had been treated like it was ts=2 and ts=8 on separate occasions.
The commit history in the PR shows the gory details; the BUILD.mk was
automated, everything else was mostly manual.
The ape loader now passes the program executable name directly as a
register. `x2` is used on aarch64, `%rdx` on x86_64. This is passed
as the third argument to `cosmo()` (M1) or `Launch` (non-M1) and is
assigned to the global `__program_executable_name`.
`GetProgramExecutableName` now returns this global's value, setting
it if it is initially null. `InitProgramExecutableName` first tries
exotic, secure methods: `KERN_PROC_PATHNAME` on FreeBSD/NetBSD, and
`/proc` on Linux. If those produce a reasonable response (i.e., not
`"/usr/bin/ape"`, which happens with the loader before this change),
that is used. Otherwise, if `issetugid()`, the empty string is used.
Otherwise, the old argv/envp parsing code is run.
The value returned from the loader is always the full absolute path
of the binary to be executed, having passed through `realpath`. For
the non-M1 loader, this necessitated writing `RealPath`, which uses
`readlinkat` of `"/proc/self/fd/[progfd]"` on Linux, `F_GETPATH` on
Xnu, and the `__realpath` syscall on OpenBSD. On FreeBSD/NetBSD, it
punts to `GetProgramExecutableName`, which is secure on those OSes.
With the loader, all platforms now have a secure program executable
name. With no loader or an old loader, everything still works as it
did, but setuid/setgid is not supported if the insecure pathfinding
code would have been needed.
Fixes#991.
We have received multiple reports of GCC breaking builds when compiler
flags like `-std=c11` were being passed. The workaround until the next
release is to simply not define `__STRICT_ANSI__` which is a bad idea.
At least in neovim, `│vi:` is not recognized as a modeline because it
has no preceding whitespace. After fixing this, opening a file yields
an error because `net` is not an option. (`noet`, however, is.)
* Introduce env.com
Handy tool for debugging environment issues.
* Inject path as COSMOPOLITAN_PROGRAM_EXECUTABLE
`argv[0]` was previously being used as a communication channel between
the loader and the binary, giving the binary its full path for use e.g.
in `GetProgramExecutableName`. But `argv[0]` is not a good channel for
this; much of what made 2a3813c6 so gross is due to that.
This change fixes the issue by preserving `argv[0]` and establishing a
new communication channel: `COSMOPOLITAN_PROGRAM_EXECUTABLE`.
The M1 loader will always set this as the first variable. Linux should
soon follow. On the other side, `GetProgramExecutableName` checks that
variable first. If it sees it, it trusts it as-is.
A lot of the churn in `ape/ape-m1.c` in this change is actually backing
out hacks introduced in 2a3813c6; the best comparison is:
git diff 2a3813c6^..
* Better refcounting
Cribbed from [Rust Arc][1] and the [Boost docs][2]:
"""
Increasing the reference counter can always be done with
memory_order_relaxed: New references to an object can only be formed
from an existing reference, and passing an existing reference from one
thread to another must already provide any required synchronization.
It is important to enforce any possible access to the object in one
thread (through an existing reference) to happen before deleting the
object in a different thread. This is achieved by a "release" operation
after dropping a reference (any access to the object through this
reference must obviously happened before), and an "acquire" operation
before deleting the object.
It would be possible to use memory_order_acq_rel for the fetch_sub
operation, but this results in unneeded "acquire" operations when the
reference counter does not yet reach zero and may impose a performance
penalty.
"""
[1] https://moshg.github.io/rust-std-ja/src/alloc/arc.rs.html
[2] https://www.boost.org/doc/libs/1_55_0/doc/html/atomic/usage_examples.html
* Make ZiposHandle's pos atomic
Implements a somewhat stronger guarantee than POSIX specifies: reads and
seeks are atomic. They may be arbitrarily reordered between threads, but
each one happens all the way and leaves the fd in a consistent state.
This is achieved by "locking" pos in __zipos_read by storing SIZE_MAX to
pos during the operation, so only one can be in-flight at a time. Seeks,
on the other hand, just update pos in one go, and rerun if it changed in
the meantime.
I used `LIKELY` / `UNLIKELY` to pessimize the concurrent case; hopefully
that buys back some performance.
* Implement __zipos_dup
Makes ZiposHandle reference-counted by an `rc` field in a union with its
freelist `next` pointer. The functions `__zipos_free` and `__zipos_keep`
function as incref/decref for it. Adds `__zipos_postdup` to fix metadata
on file descriptors after dup-like operations, and adds zipos support to
`sys_dup_nt` + `sys_close_nt`.
* Remove noop __zipos_postdup
rc is never a zipos file because it is always a previously unused file
descriptor. fd is never a zipos file because that case has been handled
above by __zipos_fcntl.
On UNIX if dup2(newfd) was a ZipOS file descriptor, then its resources
weren't being released, and the newly created file descriptor would be
mistaken for ZipOS due to its memory not being cleared. On Windows, an
issue also existed relating to newfd resources not being released.
