A program that names an interpreter in PT_INTERP gets it loaded too, at
the bottom of the mmap area, and started instead -- with AT_PHDR,
AT_PHENT, AT_PHNUM, AT_BASE and AT_ENTRY to find the program by. ET_DYN
images are placed at a base: the interpreter there, a PIE program where
a fixed one would go. Static musl programs get AT_PHDR now as well,
which is how musl finds their TLS template.
mmap(MAP_FIXED) of a file handed back zeroed pages whatever the
descriptor said, and kept no record of them, so fork() did not copy
them. A dynamic linker maps every library segment after the first that
way. Fixed mappings now read the file and are recorded wherever no
mapping already covers them.
musl is built shared as well as static, and libc.so ships as
/lib/ld-musl-x86_64.so.1 -- libc and loader in one file. Every port
still links -static on purpose.
cmd/dynhello is the test: against libc.so and a library of its own,
checking TLS, the heap, and a fork whose child still has both.
mprotect is accepted and not enforced yet.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
Nexoniarz is the sole author and SchOS was never published under
Apache-2.0, so this is a straight relicence. LICENSE is the FSF GPLv2 text,
every first-party SPDX header moves to GPL-2.0-or-later, and NOTICE,
README.md, docs/licensing.md and the site say so. projects/schfs-linux
follows the rest of the tree.
The GPL gives copyleft: a fork has to ship its source. It also lifts the
old "Linux drivers, never" rule, since GPL-2.0-only code combines with
GPL-2.0-or-later. "Or later" leaves room for GPLv3, but one binary still
has to pick one version, so docs/licensing.md now keeps Apache-2.0 and
GPLv3 code out of the kernel to keep Linux code possible there. BSD
4-clause code goes from "avoid" to "no", because the advertising clause
is GPL-incompatible.
LDLS still ships no .ko. That boundary is now project policy rather than
a legal requirement, and ldls.md, devices.md and licensing.md section 6
say so. refmod declares license=GPL, and ldls-check passes (27 checks).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Developed from both Windows and Linux, so nothing in the build should
care which host it runs on. It did, in four places.
Toolchain: one path instead of two. clang is a cross-compiler by
construction, so a single LLVM install targets bare-metal ELF, 16/32-bit
code below 1 MB, and Linux/musl userland from any host -- which is how
the Windows build already worked. The GNU branch beside it had drifted
into passing --no-warn-rwx-segments, a hard error on lld, which is the
default linker on both FreeBSD and macOS; and it required a brewed
x86_64-elf-gcc before anything built on a Mac at all. GNU is kept as a
fallback (USE_GNU=1) but clang+lld is chosen whenever both are present.
Host tools use the host's own cc; only mingw needs naming explicitly.
tools/mkschfs.c included <sys/sysmacros.h> unconditionally on non-mingw
hosts. That header is glibc/musl only -- macOS and the BSDs have neither
the header nor a need for it, since major()/minor() come from
<sys/types.h> there. Now guarded on __linux__.
Ports verified tarballs with `sha256sum -c -`, which does not exist on
macOS (shasum), FreeBSD/NetBSD (sha256), or OpenBSD (cksum -a sha256),
and each spells its check mode differently. tools/sha256check.sh picks
whichever of the five the host has and compares digests itself.
nproc is coreutils, so absent on macOS and BSD; falls through to sysctl
-n hw.ncpu before defaulting to 4.
The PowerShell tools now run under pwsh on any OS: QEMU is found on PATH
(the scoop location is a Windows-only fallback), and path literals use
forward slashes -- Join-Path $root 'build\x' produces a *filename
containing a backslash* on a Unix host. The backslash sweep is limited
to known directory prefixes on purpose: bootcheck sends
printf 'caf\303\251' to the guest to test UTF-8, and a blanket
substitution would have quietly changed what that asserts.
Also fixes six tools left booting build/fs.img, which stopped being
bootable when SchFS became the root filesystem: crashshot, dispshot,
fbshot, splashshot, textshot and ttyshot all take build/schfs.img now,
and the -SchFS switches that used to select it are gone.
Verified on Windows: full build, and bootcheck green. The Linux, macOS
and BSD paths are written from their documented behaviour and are NOT
executed here -- this machine has no WSL and no second host.
Removes the "-unix" element and with it any trademark exposure to The
Open Group.
The split follows the ecosystem layout: SchOS is the system, and the
kernel has its own name. Kernel-identity strings are the only places
that take SchIFT -- uname(2) sysname, /proc/version, and the two licence
sentences that say "kernel" outright. That is what every Unix does here:
`uname -s` on Linux reports the kernel, not the distribution. Everything
a user reads as the product -- panic screen, boot menu, error prefixes,
docs, LICENSE, NOTICE -- is SchOS.
schunix.img is schos.img, the logo assets and the musl TLS patch are
renamed, and __SCHUNIX__ is __SCHOS__ (the define and the patch that
consumes it moved together).
Two things the rename broke, both found by the bootcheck suite:
- shmtest wrote "SCHUNIX-MMAP-OK" with a hardcoded length of 15 and
compared it back by hand-counted offsets (m[3]=='U', m[14]=='K').
The shorter marker left the write running two bytes past the literal
and the compare reading past the data, failing a file-backed mmap
that was working correctly. Now written and compared through one
constant with sizeof.
- bootcheck asserted a 31-byte file after appending to
"hello-from-schunix"; the shorter string makes it 29.
Both are the same mistake: a string literal whose length is written out
somewhere else. Full suite green -- base, Tty, Ps, Sock, Fb, Usb, Evdev.
An x86-64 operating system built from xv6, now largely rewritten: SMP,
a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF
rasteriser, and a Linux-numbered syscall ABI.
No history before this point -- the tree was never under version control.
This commit exists so the rename that follows has something to undo to.
