From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 25 Feb 2024 02:06:00 +0000 (+0000)
Subject: nix: Provide a compat version of pipe for 0.28
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=494632bd10d605725f499eac4dbb3790fe8e3f9e;p=hippotat.git

nix: Provide a compat version of pipe for 0.28

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/server/daemon.rs b/server/daemon.rs
index 45a8f81..48b664a 100644
--- a/server/daemon.rs
+++ b/server/daemon.rs
@@ -154,7 +154,7 @@ impl Daemoniser {
         .context("open /dev/null");
       mdup2(null_fd, 0, "null onto stdin");
 
-      let (st_rfd, st_wfd) = pipe().context("pipe");
+      let (st_rfd, st_wfd) = compat::pipe().context("pipe");
 
       match fork().context("fork (1)") {
         ForkResult::Child => { }
diff --git a/src/compat.rs b/src/compat.rs
index f02d981..220ab11 100644
--- a/src/compat.rs
+++ b/src/compat.rs
@@ -1,4 +1,6 @@
+#![allow(unused_imports)]
 
+use std::os::fd::IntoRawFd;
 use cfg_if::cfg_if;
 use crate::prelude::*;
 
@@ -35,3 +37,19 @@ pub unsafe fn write(fd: c_int, buf: &[u8]) -> nix::Result<usize> {
     buf,
   )
 }
+
+/// Version of [`nix::unistd::pipe`] with a fixed type for the fd
+//
+///  * nix <=0.27 returns a pair of `c_int`
+///  * nix >=0.28 returns a pair of `OwnedFd`
+pub fn pipe() -> nix::Result<(c_int, c_int)> {
+  let (a, b) = nix::unistd::pipe()?;
+  let map = |fd| { cfg_if! {
+    if #[cfg(nix_ge_0_28)] {
+      OwnedFd::into_raw_fd(fd)
+    } else {
+      fd
+    }
+  }};
+  Ok((map(a), map(b)))
+}