feat: Add is_read_only flag for disks across all platforms

- Implement is_read_only flag for disks on macOS, FreeBSD, Linux, and Windows
- Add is_read_only() method to the common Disk struct
- Update documentation for the new is_read_only() method
- Ensure consistent implementation across all supported platforms

This PR was written with the assistance of aider.

src/common/disk.rs

@@ -117,6 +117,20 @@ impl Disk {
         self.inner.is_removable()
     }
 
+    /// Returns `true` if the disk is read-only.
+    ///
+    /// ```no_run
+    /// use sysinfo::Disks;
+    ///
+    /// let disks = Disks::new_with_refreshed_list();
+    /// for disk in disks.list() {
+    ///     println!("[{:?}] is read-only: {}", disk.name(), disk.is_read_only());
+    /// }
+    /// ```
+    pub fn is_read_only(&self) -> bool {
+        self.inner.is_read_only()
+    }
+
     /// Updates the disk' information.
     ///
     /// ```no_run

src/unix/apple/disk.rs

@@ -28,6 +28,7 @@ pub(crate) struct DiskInner {
     pub(crate) total_space: u64,
     pub(crate) available_space: u64,
     pub(crate) is_removable: bool,
+    pub(crate) is_read_only: bool,
 }
 
 impl DiskInner {
@@ -59,6 +60,10 @@ impl DiskInner {
         self.is_removable
     }
 
+    pub(crate) fn is_read_only(&self) -> bool {
+        self.is_read_only
+    }
+
     pub(crate) fn refresh(&mut self) -> bool {
         unsafe {
             if let Some(requested_properties) = build_requested_properties(&[
@@ -422,6 +427,8 @@ unsafe fn new_disk(
         )
     };
 
+    let is_read_only = (c_disk.f_flags & libc::MNT_RDONLY) != 0;
+
     Some(Disk {
         inner: DiskInner {
             type_,
@@ -432,6 +439,7 @@ unsafe fn new_disk(
             total_space,
             available_space,
             is_removable,
+            is_read_only,
         },
     })
 }

src/unix/freebsd/disk.rs

@@ -16,6 +16,7 @@ pub(crate) struct DiskInner {
     available_space: u64,
     file_system: OsString,
     is_removable: bool,
+    is_read_only: bool,
 }
 
 impl DiskInner {
@@ -47,6 +48,10 @@ impl DiskInner {
         self.is_removable
     }
 
+    pub(crate) fn is_read_only(&self) -> bool {
+        self.is_read_only
+    }
+
     pub(crate) fn refresh(&mut self) -> bool {
         unsafe {
             let mut vfs: libc::statvfs = std::mem::zeroed();
@@ -154,6 +159,8 @@ pub unsafe fn get_all_list(container: &mut Vec<Disk>) {
 
         let f_frsize: u64 = vfs.f_frsize as _;
 
+        let is_read_only = (vfs.f_flag & libc::ST_RDONLY) != 0;
+
         container.push(Disk {
             inner: DiskInner {
                 name,
@@ -163,6 +170,7 @@ pub unsafe fn get_all_list(container: &mut Vec<Disk>) {
                 available_space: vfs.f_favail.saturating_mul(f_frsize),
                 file_system: OsString::from_vec(fs_type),
                 is_removable,
+                is_read_only,
             },
         });
     }

src/unix/linux/disk.rs

@@ -24,6 +24,7 @@ pub(crate) struct DiskInner {
     total_space: u64,
     available_space: u64,
     is_removable: bool,
+    is_read_only: bool,
 }
 
 impl DiskInner {
@@ -55,6 +56,10 @@ impl DiskInner {
         self.is_removable
     }
 
+    pub(crate) fn is_read_only(&self) -> bool {
+        self.is_read_only
+    }
+
     pub(crate) fn refresh(&mut self) -> bool {
         unsafe {
             let mut stat: statvfs = mem::zeroed();
@@ -103,6 +108,7 @@ fn new_disk(
     let type_ = find_type_for_device_name(device_name);
     let mut total = 0;
     let mut available = 0;
+    let mut is_read_only = false;
     unsafe {
         let mut stat: statvfs = mem::zeroed();
         if retry_eintr!(statvfs(mount_point_cpath.as_ptr() as *const _, &mut stat)) == 0 {
@@ -111,6 +117,7 @@ fn new_disk(
             let bavail = cast!(stat.f_bavail);
             total = bsize.saturating_mul(blocks);
             available = bsize.saturating_mul(bavail);
+            is_read_only = (stat.f_flag & libc::ST_RDONLY) != 0;
         }
         if total == 0 {
             return None;
@@ -128,6 +135,7 @@ fn new_disk(
                 total_space: cast!(total),
                 available_space: cast!(available),
                 is_removable,
+                is_read_only,
             },
         })
     }

src/unknown/disk.rs

@@ -35,6 +35,10 @@ impl DiskInner {
         false
     }
 
+    pub(crate) fn is_read_only(&self) -> bool {
+        false
+    }
+
     pub(crate) fn refresh(&mut self) -> bool {
         true
     }

src/windows/disk.rs

@@ -12,7 +12,7 @@ use windows::core::{Error, HRESULT, PCWSTR};
 use windows::Win32::Foundation::MAX_PATH;
 use windows::Win32::Storage::FileSystem::{
     FindFirstVolumeW, FindNextVolumeW, FindVolumeClose, GetDiskFreeSpaceExW, GetDriveTypeW,
-    GetVolumeInformationW, GetVolumePathNamesForVolumeNameW,
+    GetVolumeInformationW, GetVolumePathNamesForVolumeNameW, FILE_READ_ONLY_VOLUME,
 };
 use windows::Win32::System::Ioctl::{
     PropertyStandardQuery, StorageDeviceSeekPenaltyProperty, DEVICE_SEEK_PENALTY_DESCRIPTOR,
@@ -125,6 +125,7 @@ pub(crate) struct DiskInner {
     total_space: u64,
     available_space: u64,
     is_removable: bool,
+    is_read_only: bool,
 }
 
 impl DiskInner {
@@ -156,6 +157,10 @@ impl DiskInner {
         self.is_removable
     }
 
+    pub(crate) fn is_read_only(&self) -> bool {
+        self.is_read_only
+    }
+
     pub(crate) fn refresh(&mut self) -> bool {
         if self.total_space != 0 {
             unsafe {
@@ -239,12 +244,14 @@ pub(crate) unsafe fn get_list() -> Vec<Disk> {
             }
             let mut name = [0u16; MAX_PATH as usize + 1];
             let mut file_system = [0u16; 32];
+            let mut flags = 0;
             let volume_info_res = GetVolumeInformationW(
                 raw_volume_name,
                 Some(&mut name),
                 None,
                 None,
                 None,
+                Some(&mut flags),
                 Some(&mut file_system),
             )
             .is_ok();
@@ -255,6 +262,7 @@ pub(crate) unsafe fn get_list() -> Vec<Disk> {
                 );
                 return Vec::new();
             }
+            let is_read_only = (flags & FILE_READ_ONLY_VOLUME) != 0;
 
             let mount_paths = get_volume_path_names_for_volume_name(&volume_name[..]);
             if mount_paths.is_empty() {
@@ -324,6 +332,7 @@ pub(crate) unsafe fn get_list() -> Vec<Disk> {
                         total_space,
                         available_space,
                         is_removable,
+                        is_read_only,
                     },
                 })
                 .collect::<Vec<_>>()