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56 lines
1.6 KiB
Go
56 lines
1.6 KiB
Go
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package sysfs
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import (
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"unsafe"
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"github.com/tetratelabs/wazero/experimental/sys"
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)
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// pollFd is the struct to query for file descriptor events using poll.
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type pollFd struct {
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// fd is the file descriptor.
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fd int32
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// events is a bitmap containing the requested events.
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events int16
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// revents is a bitmap containing the returned events.
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revents int16
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}
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// newPollFd is a constructor for pollFd that abstracts the platform-specific type of file descriptors.
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func newPollFd(fd uintptr, events, revents int16) pollFd {
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return pollFd{fd: int32(fd), events: events, revents: revents}
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}
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// _POLLIN subscribes a notification when any readable data is available.
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const _POLLIN = 0x0001
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// _poll implements poll on Darwin via the corresponding libc function.
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func _poll(fds []pollFd, timeoutMillis int32) (n int, errno sys.Errno) {
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var fdptr *pollFd
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nfds := len(fds)
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if nfds > 0 {
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fdptr = &fds[0]
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}
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n1, _, err := syscall_syscall6(
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libc_poll_trampoline_addr,
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uintptr(unsafe.Pointer(fdptr)),
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uintptr(nfds),
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uintptr(int(timeoutMillis)),
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uintptr(unsafe.Pointer(nil)),
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uintptr(unsafe.Pointer(nil)),
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uintptr(unsafe.Pointer(nil)))
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return int(n1), sys.UnwrapOSError(err)
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}
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// libc_poll_trampoline_addr is the address of the
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// `libc_poll_trampoline` symbol, defined in `poll_darwin.s`.
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//
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// We use this to invoke the syscall through syscall_syscall6 imported below.
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var libc_poll_trampoline_addr uintptr
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// Imports the select symbol from libc as `libc_poll`.
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//
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// Note: CGO mechanisms are used in darwin regardless of the CGO_ENABLED value
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// or the "cgo" build flag. See /RATIONALE.md for why.
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//go:cgo_import_dynamic libc_poll poll "/usr/lib/libSystem.B.dylib"
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