8d3874d3c8
Signed-off-by: Adrian Cole <adrian@tetrate.io> Signed-off-by: Edoardo Vacchi <evacchi@users.noreply.github.com> Co-authored-by: Edoardo Vacchi <evacchi@users.noreply.github.com>
58 lines
1.6 KiB
Go
58 lines
1.6 KiB
Go
package sysfs
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import (
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"syscall"
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"time"
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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 Linux via ppoll.
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func _poll(fds []pollFd, timeoutMillis int32) (n int, errno sys.Errno) {
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var ts syscall.Timespec
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if timeoutMillis >= 0 {
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ts = syscall.NsecToTimespec(int64(time.Duration(timeoutMillis) * time.Millisecond))
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}
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return ppoll(fds, &ts)
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}
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// ppoll is a poll variant that allows to subscribe to a mask of signals.
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// However, we do not need such mask, so the corresponding argument is always nil.
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func ppoll(fds []pollFd, timespec *syscall.Timespec) (n int, err sys.Errno) {
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var fdptr *pollFd
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nfd := len(fds)
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if nfd != 0 {
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fdptr = &fds[0]
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}
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n1, _, errno := syscall.Syscall6(
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uintptr(syscall.SYS_PPOLL),
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uintptr(unsafe.Pointer(fdptr)),
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uintptr(nfd),
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uintptr(unsafe.Pointer(timespec)),
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uintptr(unsafe.Pointer(nil)), // sigmask is currently always ignored
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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(errno)
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}
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