26 lines
895 B
Go
26 lines
895 B
Go
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// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
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// SPDX-License-Identifier: MIT
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package nfsfs
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import "syscall"
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// mknod creates a device node. It needs CAP_MKNOD on Linux, and a failure
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// of permission is reported as such rather than as an io error. The kind
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// is picked before the single call: a second mknod over an existing node
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// fails EEXIST and leaves the wrong kind behind.
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func mknod(path string, spec CreateSpec, perm uint32) error {
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dev := int(makedev(spec.Major, spec.Minor))
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kind := uint32(syscall.S_IFCHR)
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if spec.Kind == KindBlk {
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kind = syscall.S_IFBLK
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}
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return syscall.Mknod(path, perm|kind, dev)
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}
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// makedev assembles a device number the way the kernel expects it.
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func makedev(major, minor uint32) uint64 {
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return uint64(minor&0xff) | uint64(major&0xfff)<<8 |
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uint64(minor&0xfff00)<<12 | uint64(major&0xfffff000)<<32
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}
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