Add mount syscall (#494)

Signed-off-by: Alex Saveau <saveau.alexandre@gmail.com>

Signed-off-by: Alex Saveau <saveau.alexandre@gmail.com>

Author: SUPERCILEX

src/backend/libc/fs/syscalls.rs

@@ -1799,3 +1799,22 @@ struct Attrlist {
     fileattr: Attrgroup,
     forkattr: Attrgroup,
 }
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+pub(crate) fn mount(
+    source: Option<&CStr>,
+    target: &CStr,
+    file_system_type: Option<&CStr>,
+    flags: super::types::MountFlagsArg,
+    data: Option<&CStr>,
+) -> io::Result<()> {
+    unsafe {
+        ret(c::mount(
+            source.map_or_else(null, CStr::as_ptr),
+            target.as_ptr(),
+            file_system_type.map_or_else(null, CStr::as_ptr),
+            flags.0,
+            data.map_or_else(null, CStr::as_ptr).cast(),
+        ))
+    }
+}

src/backend/libc/fs/types.rs

@@ -1114,3 +1114,83 @@ pub const NFS_SUPER_MAGIC: FsWord = 0x0000_6969;
 #[repr(transparent)]
 #[derive(Copy, Clone)]
 pub struct copyfile_state_t(pub(crate) *mut c::c_void);
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    /// `MS_*` constants for use with [`mount`][crate::fs::mount].
+    pub struct MountFlags: c::c_ulong {
+        /// `MS_BIND`
+        const BIND = c::MS_BIND;
+
+        /// `MS_DIRSYNC`
+        const DIRSYNC = c::MS_DIRSYNC;
+
+        /// `MS_LAZYTIME`
+        const LAZYTIME = c::MS_LAZYTIME;
+
+        /// `MS_MANDLOCK`
+        #[doc(alias = "MANDLOCK")]
+        const PERMIT_MANDATORY_FILE_LOCKING = c::MS_MANDLOCK;
+
+        /// `MS_NOATIME`
+        const NOATIME = c::MS_NOATIME;
+
+        /// `MS_NODEV`
+        const NODEV = c::MS_NODEV;
+
+        /// `MS_NODIRATIME`
+        const NODIRATIME = c::MS_NODIRATIME;
+
+        /// `MS_NOEXEC`
+        const NOEXEC = c::MS_NOEXEC;
+
+        /// `MS_NOSUID`
+        const NOSUID = c::MS_NOSUID;
+
+        /// `MS_RDONLY`
+        const RDONLY = c::MS_RDONLY;
+
+        /// `MS_REC`
+        const REC = c::MS_REC;
+
+        /// `MS_RELATIME`
+        const RELATIME = c::MS_RELATIME;
+
+        /// `MS_SILENT`
+        const SILENT = c::MS_SILENT;
+
+        /// `MS_STRICTATIME`
+        const STRICTATIME = c::MS_STRICTATIME;
+
+        /// `MS_SYNCHRONOUS`
+        const SYNCHRONOUS = c::MS_SYNCHRONOUS;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    /// `MS_*` constants for use with [`change_mount`][crate::fs::mount::change_mount].
+    pub struct MountPropagationFlags: c::c_ulong {
+        /// `MS_SHARED`
+        const SHARED = c::MS_SHARED;
+        /// `MS_PRIVATE`
+        const PRIVATE = c::MS_PRIVATE;
+        /// `MS_SLAVE`
+        const SLAVE = c::MS_SLAVE;
+        /// `MS_UNBINDABLE`
+        const UNBINDABLE = c::MS_UNBINDABLE;
+        /// `MS_REC`
+        const REC = c::MS_REC;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    pub(crate) struct InternalMountFlags: c::c_ulong {
+        const REMOUNT = c::MS_REMOUNT;
+        const MOVE = c::MS_MOVE;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+pub(crate) struct MountFlagsArg(pub(crate) c::c_ulong);

src/backend/linux_raw/conv.rs

@@ -665,6 +665,15 @@ impl<'a, Num: ArgNumber, T> From<&'a mut MaybeUninit<T>> for ArgReg<'a, Num> {
     }
 }
 
+#[cfg(feature = "fs")]
+#[cfg(any(target_os = "android", target_os = "linux"))]
+impl<'a, Num: ArgNumber> From<crate::backend::fs::types::MountFlagsArg> for ArgReg<'a, Num> {
+    #[inline]
+    fn from(flags: crate::backend::fs::types::MountFlagsArg) -> Self {
+        c_uint(flags.0)
+    }
+}
+
 /// Convert a `usize` returned from a syscall that effectively returns `()` on
 /// success.
 ///

src/backend/linux_raw/fs/syscalls.rs

@@ -1395,3 +1395,24 @@ pub(crate) fn sendfile(
         ))
     }
 }
+
+#[inline]
+#[cfg(any(target_os = "android", target_os = "linux"))]
+pub(crate) fn mount(
+    source: Option<&CStr>,
+    target: &CStr,
+    file_system_type: Option<&CStr>,
+    flags: super::types::MountFlagsArg,
+    data: Option<&CStr>,
+) -> io::Result<()> {
+    unsafe {
+        ret(syscall_readonly!(
+            __NR_mount,
+            source,
+            target,
+            file_system_type,
+            flags,
+            data
+        ))
+    }
+}

src/backend/linux_raw/fs/types.rs

@@ -644,3 +644,86 @@ pub const PROC_SUPER_MAGIC: FsWord = linux_raw_sys::general::PROC_SUPER_MAGIC as
 
 /// `NFS_SUPER_MAGIC`—The magic number for the NFS filesystem.
 pub const NFS_SUPER_MAGIC: FsWord = linux_raw_sys::general::NFS_SUPER_MAGIC as FsWord;
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    /// `MS_*` constants for use with [`mount`][crate::fs::mount].
+    pub struct MountFlags: c::c_uint {
+        /// `MS_BIND`
+        const BIND = linux_raw_sys::general::MS_BIND;
+
+        /// `MS_DIRSYNC`
+        const DIRSYNC = linux_raw_sys::general::MS_DIRSYNC;
+
+        /// `MS_LAZYTIME`
+        const LAZYTIME = linux_raw_sys::general::MS_LAZYTIME;
+
+        /// `MS_MANDLOCK`
+        #[doc(alias = "MANDLOCK")]
+        const PERMIT_MANDATORY_FILE_LOCKING = linux_raw_sys::general::MS_MANDLOCK;
+
+        /// `MS_NOATIME`
+        const NOATIME = linux_raw_sys::general::MS_NOATIME;
+
+        /// `MS_NODEV`
+        const NODEV = linux_raw_sys::general::MS_NODEV;
+
+        /// `MS_NODIRATIME`
+        const NODIRATIME = linux_raw_sys::general::MS_NODIRATIME;
+
+        /// `MS_NOEXEC`
+        const NOEXEC = linux_raw_sys::general::MS_NOEXEC;
+
+        /// `MS_NOSUID`
+        const NOSUID = linux_raw_sys::general::MS_NOSUID;
+
+        /// `MS_RDONLY`
+        const RDONLY = linux_raw_sys::general::MS_RDONLY;
+
+        /// `MS_REC`
+        const REC = linux_raw_sys::general::MS_REC;
+
+        /// `MS_RELATIME`
+        const RELATIME = linux_raw_sys::general::MS_RELATIME;
+
+        /// `MS_SILENT`
+        const SILENT = linux_raw_sys::general::MS_SILENT;
+
+        /// `MS_STRICTATIME`
+        const STRICTATIME = linux_raw_sys::general::MS_STRICTATIME;
+
+        /// `MS_SYNCHRONOUS`
+        const SYNCHRONOUS = linux_raw_sys::general::MS_SYNCHRONOUS;
+
+        /// `MS_NOSYMFOLLOW`
+        const NOSYMFOLLOW = linux_raw_sys::general::MS_NOSYMFOLLOW;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    /// `MS_*` constants for use with [`change_mount`][crate::fs::mount::change_mount].
+    pub struct MountPropagationFlags: c::c_uint {
+        /// `MS_SHARED`
+        const SHARED = linux_raw_sys::general::MS_SHARED;
+        /// `MS_PRIVATE`
+        const PRIVATE = linux_raw_sys::general::MS_PRIVATE;
+        /// `MS_SLAVE`
+        const SLAVE = linux_raw_sys::general::MS_SLAVE;
+        /// `MS_UNBINDABLE`
+        const UNBINDABLE = linux_raw_sys::general::MS_UNBINDABLE;
+        /// `MS_REC`
+        const REC = linux_raw_sys::general::MS_REC;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+bitflags! {
+    pub(crate) struct InternalMountFlags: c::c_uint {
+        const REMOUNT = linux_raw_sys::general::MS_REMOUNT;
+        const MOVE = linux_raw_sys::general::MS_MOVE;
+    }
+}
+
+#[cfg(any(target_os = "android", target_os = "linux"))]
+pub(crate) struct MountFlagsArg(pub(crate) c::c_uint);

src/fs/constants.rs

@@ -12,7 +12,7 @@ pub use backend::fs::types::AtFlags;
 pub use backend::fs::types::{CloneFlags, CopyfileFlags};
 
 #[cfg(any(target_os = "android", target_os = "linux"))]
-pub use backend::fs::types::{RenameFlags, ResolveFlags};
+pub use backend::fs::types::{MountFlags, MountPropagationFlags, RenameFlags, ResolveFlags};
 
 #[cfg(not(target_os = "redox"))]
 pub use backend::fs::types::Dev;

src/fs/mod.rs

@@ -48,8 +48,9 @@ mod makedev;
 #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
 mod memfd_create;
 #[cfg(any(target_os = "android", target_os = "linux"))]
+mod mount;
+#[cfg(any(target_os = "android", target_os = "linux"))]
 mod openat2;
-#[cfg(feature = "fs")]
 #[cfg(any(target_os = "android", target_os = "linux"))]
 mod raw_dir;
 #[cfg(target_os = "linux")]
@@ -99,14 +100,12 @@ pub use constants::CloneFlags;
 /// `copyfile_flags_t`
 #[cfg(any(target_os = "ios", target_os = "macos"))]
 pub use constants::CopyfileFlags;
-#[cfg(any(target_os = "android", target_os = "linux"))]
-pub use constants::RenameFlags;
-#[cfg(any(target_os = "android", target_os = "linux"))]
-pub use constants::ResolveFlags;
 pub use constants::{Access, FdFlags, Mode, Nsecs, OFlags, Secs, Timespec};
 #[cfg(not(target_os = "redox"))]
 pub use constants::{AtFlags, Dev};
 #[cfg(any(target_os = "android", target_os = "linux"))]
+pub use constants::{MountFlags, MountPropagationFlags, RenameFlags, ResolveFlags};
+#[cfg(any(target_os = "android", target_os = "linux"))]
 pub use copy_file_range::copy_file_range;
 #[cfg(not(target_os = "redox"))]
 pub use cwd::cwd;
@@ -203,8 +202,9 @@ pub use makedev::{major, makedev, minor};
 #[cfg(any(target_os = "android", target_os = "freebsd", target_os = "linux"))]
 pub use memfd_create::{memfd_create, MemfdFlags};
 #[cfg(any(target_os = "android", target_os = "linux"))]
+pub use mount::{bind_mount, change_mount, mount, move_mount, recursive_bind_mount, remount};
+#[cfg(any(target_os = "android", target_os = "linux"))]
 pub use openat2::openat2;
-#[cfg(feature = "fs")]
 #[cfg(any(target_os = "android", target_os = "linux"))]
 pub use raw_dir::{RawDir, RawDirEntry};
 #[cfg(target_os = "linux")]