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internal/poll: handle (0, EINVAL) return from sendfile on Solaris

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Also check for GOOS=illumos as well as GOOS=solaris.

Change-Id: I887e6cddc1b8ad0f4624c9491e089c6bb8bce70e
Reviewed-on: https://go-review.googlesource.com/c/go/+/622977
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Commit-Queue: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
This commit is contained in:
Damien Neil 2024-10-29 10:31:23 -07:00 committed by Gopher Robot
parent 76a8409eb8
commit 0fd414c652
1 changed files with 35 additions and 41 deletions
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58
src/internal/poll/sendfile_unix.go
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@ -36,11 +36,9 @@ func SendFile(dstFD *FD, src int, size int64) (n int64, err error, handled bool)
return sendFile(dstFD, src, nil, size)
}
// Darwin/FreeBSD/DragonFly/Solaris's sendfile implementation
// doesn't use the current position of the file --
// if you pass it offset 0, it starts from offset 0.
// There's no way to tell it "start from current position",
// so we have to manage that explicitly.
// Non-Linux sendfile implementations don't use the current position of the source file,
// so we need to look up the position, pass it explicitly, and adjust it after
// sendfile returns.
start, err := ignoringEINTR2(func() (int64, error) {
return syscall.Seek(src, 0, io.SeekCurrent)
})
@ -48,28 +46,14 @@ func SendFile(dstFD *FD, src int, size int64) (n int64, err error, handled bool)
return 0, err, false
}
// Solaris requires us to pass a length to send,
mustReposition := false
switch runtime.GOOS {
case "solaris", "illumos":
// Solaris/illumos requires us to pass a length to send,
// rather than accepting 0 as "send everything".
//
// Seek to the end of the source file to find its length.
//
// Important: If we ever remove this block
// (because Solaris has added a way to send everything, or we discovered a
// previously-unknown existing way),
// then some of the sendFile function will need updating.
//
// On Solaris, sendfile can return n>0 and EINVAL when successfully copying to a file.
// We ignore the EINVAL in this case.
//
// On non-Solaris platforms, when size==0 we call sendfile until it returns
// n==0 and success, indicating that it has copied the entire source file.
// If we were to do this on Solaris, then the final sendfile call could return (0, EINVAL),
// which we would treat as an error rather than successful completion of the copy.
// This never happens, because when size==0 on Solaris,
// we look up the actual file size here.
// If we change that, we need to handle the (0, EINVAL) case below.
mustReposition := false
if runtime.GOOS == "solaris" && size == 0 {
if size == 0 {
end, err := ignoringEINTR2(func() (int64, error) {
return syscall.Seek(src, 0, io.SeekEnd)
})
@ -79,6 +63,7 @@ func SendFile(dstFD *FD, src int, size int64) (n int64, err error, handled bool)
size = end - start
mustReposition = true
}
}
pos := start
n, err, handled = sendFile(dstFD, src, &pos, size)
@ -115,6 +100,22 @@ func sendFile(dstFD *FD, src int, offset *int64, size int64) (written int64, err
if n > 0 {
written += int64(n)
}
switch runtime.GOOS {
case "solaris", "illumos":
// A quirk on Solaris/illumos: sendfile() claims to support out_fd
// as a regular file but returns EINVAL when the out_fd
// is not a socket of SOCK_STREAM, while it actually sends
// out data anyway and updates the file offset.
//
// We ignore EINVAL if any sendfile call returned n > 0,
// to handle the case where the last call returns 0 to indicate
// no more data to send.
if err == syscall.EINVAL && written > 0 {
err = nil
}
}
switch err {
case nil:
// We're done if sendfile copied no bytes
@ -158,18 +159,11 @@ func sendFileChunk(dst, src int, offset *int64, size int) (n int, err error) {
case "linux":
// The offset is always nil on Linux.
n, err = syscall.Sendfile(dst, src, offset, size)
case "solaris":
case "solaris", "illumos":
// Trust the offset, not the return value from sendfile.
start := *offset
n, err = syscall.Sendfile(dst, src, offset, size)
n = int(*offset - start)
// A quirk on Solaris: sendfile() claims to support out_fd
// as a regular file but returns EINVAL when the out_fd
// is not a socket of SOCK_STREAM, while it actually sends
// out data anyway and updates the file offset.
if err == syscall.EINVAL && n > 0 {
err = nil
}
default:
start := *offset
n, err = syscall.Sendfile(dst, src, offset, size)