14f0e4d0e2
Porting zsh found four defects in the kernel and one in the filesystem. None of them were about zsh; all of them had been there the whole time. **exec threw the environment away.** kernel/fs/exec.c wrote a single zero for envp with the comment "(no environment)" -- not yet, but ever, for every process. musl has been passing a perfectly good envp to execve (Linux 59, which SchOS answers) and it was never read. So $TERM was unset, $PATH was whatever each program invented, and a variable exported in a shell did not survive the exec meant to carry it. exec() takes an envp, sys_exec reads argument three, and schinit manifests grew an Environment key. The userland two-argument exec(path, argv) stays as a wrapper that passes null explicitly -- the raw stub is execve now, so a short caller cannot leave %rdx holding a stray pointer. **Which overflowed the kernel stack.** Three pointer arrays, ~1.8 KB, on a 4096-byte stack, under exec -> loaduvm -> readi -> SchFS -> btree. Pid 1 went down on the first exec. The canary caught it and named the process, which is what it is for. They live in one kalloc'd page now. **waitpid returned a bare -1** for both "no children" and "interrupted". musl reads [-4095,-1] as -errno, so userspace saw EPERM; zsh printed "wait failed: operation not permitted" and abandoned the rest of /etc/zsh/zshrc. -ECHILD and -EINTR now. Third time a bare -1 has cost real time -- on a system with no permission model, EPERM should be read as "a syscall returned -1". **NVMA was 64.** musl's allocator takes a mapping per size class and does not release them eagerly, so compinit ran out of slots and got -1, which is EPERM, which malloc turns into NULL, which zsh reports as "fatal error: out of memory" -- on a machine with 1000 MB free. 256 slots, and -ENOMEM. **And a small write to SchFS costs 58 ms.** 200 writes to one open file take 11.75 s; the same to /dev/null take 0.14 s. That is the design stated at the top of kmount.c -- one transaction group per operation, and a commit is two flushes and an uberblock -- not a bug. But compdump writes its digest with thousands of separate prints, so it takes minutes and looks like a hang. compinit -D, which skips the dump, finishes in 3.6 s. This one is a decision rather than a fix, so it is written up and left: /etc/zsh/zshrc keeps compinit switched off and explains exactly why, with the measurements. zsh runs as /bin/zsh and is the console shell. ZLE works -- arrow keys recall history through terminfo, $COLUMNS reads the real 160 because TIOCGWINSZ was fixed, colour and prompt expansion work, startup is 0.14 s. mksh keeps /bin/sh, so schinit's no-jobs fallback is a different program from the one that could have failed. Also fixed while here: AT_CLKTCK was the literal 100 and is USER_HZ; the extract rule in four ports could move a source tree inside itself when make re-ran it, which is how zsh's configure came to write modfile=zsh-5.9/... into config.modules and fail three steps later. schfs-check passes. Full writeup in docs/history/kernel.md section 14. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2
39 lines
1.5 KiB
Makefile
39 lines
1.5 KiB
Makefile
# SPDX-License-Identifier: Apache-2.0
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# SchOS ports — third-party software, one directory per port.
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# All ports are permissive-licensed (MIT, BSD, 0BSD, Apache 2.0).
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#
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# ports/musl/ libc — installs headers/libs to build/ports/musl/prefix
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# ports/mksh/ MirBSD Korn Shell — installed as sysroot/bin/sh
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# ports/toybox/ core utilities — installed as sysroot/bin/<applet>
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# ports/ncurses/ terminfo + screen library — link-time only, ships nothing
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# ports/zsh/ the Z shell — installed as sysroot/bin/zsh, beside /bin/sh
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#
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# A port directory holds only a Makefile and optional patches/. Everything
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# generated lives in build/ports/<name>/ — see mk/port.mk for the contract.
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# Tarballs are cached in dist/ and are never removed by 'clean'.
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#
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# Order matters: musl must be built before anything that links against it.
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# Ports that live in this directory but are deliberately not built by `make`.
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# Empty for now; the filter stays because the reason it existed will recur --
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# a port whose licence cannot be combined with Apache-2.0 can be kept here for
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# local testing but must never be built into a SchOS image.
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NOTPORTS :=
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PORTS := $(filter-out $(NOTPORTS), \
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$(patsubst %/,%,$(sort $(dir $(wildcard */Makefile)))))
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.PHONY: all $(PORTS) clean distclean
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all: $(PORTS)
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mksh: musl
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toybox: musl
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fastfetch: musl
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ncurses: musl
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zsh: musl ncurses
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$(PORTS):
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$(MAKE) -C $@
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clean distclean:
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for p in $(PORTS); do $(MAKE) -C $$p $@; done
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