feat: introduce macos mount API support (nix-rust#2347)

* feat: introduce macos mount API support

* feat: add doc comment

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

* feat: fix code

build.rs

@@ -19,6 +19,7 @@ fn main() {
         // cfg aliases we would like to use
         apple_targets: { any(ios, macos, watchos, tvos) },
         bsd: { any(freebsd, dragonfly, netbsd, openbsd, apple_targets) },
+        bsd_without_apple: { any(freebsd, dragonfly, netbsd, openbsd) },
         linux_android: { any(android, linux) },
         freebsdlike: { any(dragonfly, freebsd) },
         netbsdlike: { any(netbsd, openbsd) },

changelog/2347.added.md

@@ -0,0 +1 @@
+Add `mount` and `unmount` API for apple targets.

src/mount/apple.rs

@@ -0,0 +1,122 @@
+use crate::{Errno, NixPath, Result};
+use libc::c_int;
+
+libc_bitflags!(
+    /// Used with [`mount()`] and [`unmount()`].
+    pub struct MntFlags: c_int {
+        /// Do not interpret special files on the filesystem.
+        MNT_NODEV;
+        /// Enable data protection on the filesystem if the filesystem is configured for it.
+        MNT_CPROTECT;
+        /// file system is quarantined
+        MNT_QUARANTINE;
+        /// filesystem is stored locally
+        MNT_LOCAL;
+        /// quotas are enabled on filesystem
+        MNT_QUOTA;
+        /// identifies the root filesystem
+        MNT_ROOTFS;
+        /// file system is not appropriate path to user data
+        MNT_DONTBROWSE;
+        /// VFS will ignore ownership information on filesystem objects
+        MNT_IGNORE_OWNERSHIP;
+        /// filesystem was mounted by automounter
+        MNT_AUTOMOUNTED;
+        /// filesystem is journaled
+        MNT_JOURNALED;
+        /// Don't allow user extended attributes
+        MNT_NOUSERXATTR;
+        /// filesystem should defer writes
+        MNT_DEFWRITE;
+        /// don't block unmount if not responding
+        MNT_NOBLOCK;
+        /// file system is exported
+        MNT_EXPORTED;
+        /// file system written asynchronously
+        MNT_ASYNC;
+        /// Force a read-write mount even if the file system appears to be
+        /// unclean.
+        MNT_FORCE;
+        /// MAC support for objects.
+        MNT_MULTILABEL;
+        /// Do not update access times.
+        MNT_NOATIME;
+        /// Disallow program execution.
+        MNT_NOEXEC;
+        /// Do not honor setuid or setgid bits on files when executing them.
+        MNT_NOSUID;
+        /// Mount read-only.
+        MNT_RDONLY;
+        /// Causes the vfs subsystem to update its data structures pertaining to
+        /// the specified already mounted file system.
+        MNT_RELOAD;
+        /// Create a snapshot of the file system.
+        MNT_SNAPSHOT;
+        /// All I/O to the file system should be done synchronously.
+        MNT_SYNCHRONOUS;
+        /// Union with underlying fs.
+        MNT_UNION;
+        /// Indicates that the mount command is being applied to an already
+        /// mounted file system.
+        MNT_UPDATE;
+    }
+);
+
+/// Mount a file system.
+///
+/// # Arguments
+/// - `source`  -   Specifies the file system.  e.g. `/dev/sd0`.
+/// - `target` -    Specifies the destination.  e.g. `/mnt`.
+/// - `flags` -     Optional flags controlling the mount.
+/// - `data` -      Optional file system specific data.
+///
+/// # see also
+/// [`mount`](https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man2/mount.2.html)
+pub fn mount<
+    P1: ?Sized + NixPath,
+    P2: ?Sized + NixPath,
+    P3: ?Sized + NixPath,
+>(
+    source: &P1,
+    target: &P2,
+    flags: MntFlags,
+    data: Option<&P3>,
+) -> Result<()> {
+    fn with_opt_nix_path<P, T, F>(p: Option<&P>, f: F) -> Result<T>
+    where
+        P: ?Sized + NixPath,
+        F: FnOnce(*const libc::c_char) -> T,
+    {
+        match p {
+            Some(path) => path.with_nix_path(|p_str| f(p_str.as_ptr())),
+            None => Ok(f(std::ptr::null())),
+        }
+    }
+
+    let res = source.with_nix_path(|s| {
+        target.with_nix_path(|t| {
+            with_opt_nix_path(data, |d| unsafe {
+                libc::mount(
+                    s.as_ptr(),
+                    t.as_ptr(),
+                    flags.bits(),
+                    d.cast_mut().cast(),
+                )
+            })
+        })
+    })???;
+
+    Errno::result(res).map(drop)
+}
+
+/// Umount the file system mounted at `target`.
+pub fn unmount<P>(target: &P, flags: MntFlags) -> Result<()>
+where
+    P: ?Sized + NixPath,
+{
+    let res = target.with_nix_path(|cstr| unsafe {
+        libc::unmount(cstr.as_ptr(), flags.bits())
+    })?;
+
+    Errno::result(res).map(drop)
+}

src/mount/bsd.rs → src/mount/bsd_without_apple.rs

@@ -30,7 +30,7 @@ libc_bitflags!(
         #[cfg(target_os = "freebsd")]
         MNT_GJOURNAL;
         /// MAC support for objects.
-        #[cfg(any(apple_targets, target_os = "freebsd"))]
+        #[cfg(target_os = "freebsd")]
         MNT_MULTILABEL;
         /// Disable read clustering.
         #[cfg(freebsdlike)]
@@ -58,7 +58,7 @@ libc_bitflags!(
         /// Create a snapshot of the file system.
         ///
         /// See [mksnap_ffs(8)](https://www.freebsd.org/cgi/man.cgi?query=mksnap_ffs)
-        #[cfg(any(apple_targets, target_os = "freebsd"))]
+        #[cfg(target_os = "freebsd")]
         MNT_SNAPSHOT;
         /// Using soft updates.
         #[cfg(any(freebsdlike, netbsdlike))]
@@ -71,7 +71,6 @@ libc_bitflags!(
         MNT_SYNCHRONOUS;
         /// Union with underlying fs.
         #[cfg(any(
-                apple_targets,
                 target_os = "freebsd",
                 target_os = "netbsd"
         ))]

src/mount/mod.rs

@@ -5,8 +5,14 @@ mod linux;
 #[cfg(linux_android)]
 pub use self::linux::*;
 
-#[cfg(bsd)]
-mod bsd;
+#[cfg(bsd_without_apple)]
+mod bsd_without_apple;
 
-#[cfg(bsd)]
-pub use self::bsd::*;
+#[cfg(bsd_without_apple)]
+pub use self::bsd_without_apple::*;
+
+#[cfg(apple_targets)]
+mod apple;
+
+#[cfg(apple_targets)]
+pub use self::apple::*;

test/mount/mod.rs

@@ -0,0 +1,6 @@
+#[cfg(target_os = "linux")]
+mod test_mount;
+#[cfg(apple_targets)]
+mod test_mount_apple;
+#[cfg(target_os = "freebsd")]
+mod test_nmount;

test/mount/test_mount_apple.rs

@@ -0,0 +1,8 @@
+use nix::errno::Errno;
+use nix::mount::{mount, MntFlags};
+
+#[test]
+fn test_mount() {
+    let res = mount::<str, str, str>("", "", MntFlags::empty(), None);
+    assert_eq!(res, Err(Errno::ENOENT));
+}

test/test.rs

@@ -4,15 +4,14 @@ extern crate cfg_if;
 extern crate nix;
 
 mod common;
+mod mount;
 mod sys;
 #[cfg(not(target_os = "redox"))]
 mod test_dir;
 mod test_errno;
 mod test_fcntl;
 #[cfg(linux_android)]
 mod test_kmod;
-#[cfg(target_os = "linux")]
-mod test_mount;
 #[cfg(any(
     freebsdlike,
     target_os = "fushsia",
@@ -23,8 +22,6 @@ mod test_mq;
 #[cfg(not(target_os = "redox"))]
 mod test_net;
 mod test_nix_path;
-#[cfg(target_os = "freebsd")]
-mod test_nmount;
 mod test_poll;
 #[cfg(not(any(
     target_os = "redox",