d0f7acf9eb
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.
43 lines
1.9 KiB
C
43 lines
1.9 KiB
C
#pragma once
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// open(2) flags.
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//
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// These are the *Linux x86-64* values, and they have to be: every program in
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// the userland is built against a libc that sends Linux flag values, and the
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// kernel reads them with these constants. They disagreed for a long time, with
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// results that looked like filesystem corruption rather than like a mistake --
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// Linux O_APPEND (0x400) landed on Schunix's O_TRUNC, so `cmd >> file`
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// truncated the file it was meant to extend, and Linux O_TRUNC (0x200) landed
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// on O_CREATE, so `cmd > file` left whatever was past the new end in place.
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// Neither failure pointed anywhere near a header.
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//
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// Do not tidy these into a neat sequence. They are an external interface.
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#define O_RDONLY 0x000000
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#define O_WRONLY 0x000001
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#define O_RDWR 0x000002
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#define O_ACCMODE 0x000003
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#define O_CREATE 0x000040 /* Linux O_CREAT (0100) */
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#define O_CREAT O_CREATE /* the spelling every program uses */
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#define O_EXCL 0x000080 /* Linux O_EXCL (0200) */
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#define O_NOCTTY 0x000100 /* Linux O_NOCTTY (0400) */
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#define O_TRUNC 0x000200 /* Linux O_TRUNC (01000) */
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#define O_APPEND 0x000400 /* Linux O_APPEND (02000) */
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#define O_NONBLOCK 0x000800 /* Linux O_NONBLOCK (04000); no-op here */
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#define O_DIRECTORY 0x010000 /* Linux O_DIRECTORY (0200000) */
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#define O_NOFOLLOW 0x020000 /* Linux O_NOFOLLOW (0400000) */
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#define O_CLOEXEC 0x080000 /* Linux O_CLOEXEC (02000000) */
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// Schunix-only, placed above every flag Linux defines so it can never be
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// mistaken for one. 0x40000 was used before and collides with Linux O_NOATIME.
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#define O_EXTENT 0x8000000 /* sparse-extent hint */
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#define F_DUPFD 0
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#define F_GETFD 1
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#define F_SETFD 2
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#define F_GETFL 3
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#define F_SETFL 4
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#define F_DUPFD_CLOEXEC 1030 // Linux value
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#define FD_CLOEXEC 1
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