Introduce set_errno

changelog/2283.added.md

@@ -0,0 +1,4 @@
+- Added `errno::Errno::set` function
+- Added `errno::Errno::set_raw` function
+- Added `errno::Errno::last_raw` function
+- Added `errno::Errno::from_raw` function

changelog/2283.changed.md

@@ -0,0 +1,3 @@
+- Deprecated `errno::errno()` function (use `Errno::last_raw()`)
+- Deprecated `errno::from_i32()` function (use `Errno::from_raw()`)
+- Deprecated `errno::Errno::from_i32()` function (use `Errno::from_raw()`)

src/errno.rs

@@ -1,3 +1,16 @@
+//! Safe wrappers around errno functions
+//!
+//! # Example
+//! ```
+//! use nix::errno::Errno;
+//!
+//! Errno::EIO.set();
+//! assert_eq!(Errno::last(), Errno::EIO);
+//!
+//! Errno::clear();
+//! assert_eq!(Errno::last(), Errno::from_raw(0));
+//! ```
+
 use crate::Result;
 use cfg_if::cfg_if;
 use libc::{c_int, c_void};
@@ -39,34 +52,77 @@ cfg_if! {
     }
 }
 
-/// Sets the platform-specific errno to no-error
-fn clear() {
-    // Safe because errno is a thread-local variable
-    unsafe {
-        *errno_location() = 0;
-    }
-}
-
 /// Returns the platform-specific value of errno
+#[deprecated(since = "0.28.0", note = "please use `Errno::last_raw()` instead")]
 pub fn errno() -> i32 {
-    unsafe { *errno_location() }
+    Errno::last_raw()
 }
 
 impl Errno {
+    /// Returns the current value of errno
     pub fn last() -> Self {
-        last()
+        Self::from_raw(Self::last_raw())
     }
 
-    pub fn desc(self) -> &'static str {
-        desc(self)
+    /// Returns the current raw i32 value of errno
+    pub fn last_raw() -> i32 {
+        unsafe { *errno_location() }
+    }
+
+    /// Sets the value of errno.
+    ///
+    /// # Example
+    /// ```
+    /// use nix::errno::Errno;
+    ///
+    /// Errno::EIO.set();
+    ///
+    /// assert_eq!(Errno::last(), Errno::EIO);
+    /// ```
+    pub fn set(self) {
+        Self::set_raw(self as i32)
     }
 
+    /// Sets the raw i32 value of errno.
+    pub fn set_raw(errno: i32) {
+        // Safe because errno is a thread-local variable
+        unsafe {
+            *errno_location() = errno;
+        }
+    }
+
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(err: i32) -> Errno {
+        Self::from_raw(err)
+    }
+
+    pub const fn from_raw(err: i32) -> Errno {
+        #[allow(deprecated)]
         from_i32(err)
     }
 
+    pub fn desc(self) -> &'static str {
+        desc(self)
+    }
+
+    /// Sets the platform-specific errno to no-error
+    ///
+    /// ```
+    /// use nix::errno::Errno;
+    ///
+    /// Errno::EIO.set();
+    ///
+    /// Errno::clear();
+    ///
+    /// let err = Errno::last();
+    /// assert_ne!(err, Errno::EIO);
+    /// assert_eq!(err, Errno::from_raw(0));
+    /// ```
     pub fn clear() {
-        clear()
+        Self::set_raw(0)
     }
 
     /// Returns `Ok(value)` if it does not contain the sentinel value. This
@@ -135,14 +191,10 @@ impl TryFrom<io::Error> for Errno {
     type Error = io::Error;
 
     fn try_from(ioerror: io::Error) -> std::result::Result<Self, io::Error> {
-        ioerror.raw_os_error().map(Errno::from_i32).ok_or(ioerror)
+        ioerror.raw_os_error().map(Errno::from_raw).ok_or(ioerror)
     }
 }
 
-fn last() -> Errno {
-    Errno::from_i32(errno())
-}
-
 fn desc(errno: Errno) -> &'static str {
     use self::Errno::*;
     match errno {
@@ -929,6 +981,10 @@ mod consts {
         pub const ENOTSUP: Errno = Errno::EOPNOTSUPP;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -1192,6 +1248,10 @@ mod consts {
         pub const EDEADLOCK: Errno = Errno::EDEADLK;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -1419,6 +1479,10 @@ mod consts {
         pub const EOPNOTSUPP: Errno = Errno::ENOTSUP;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -1636,6 +1700,10 @@ mod consts {
         pub const EOPNOTSUPP: Errno = Errno::ENOTSUP;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -1848,6 +1916,10 @@ mod consts {
         pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -2062,6 +2134,10 @@ mod consts {
         pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -2265,6 +2341,10 @@ mod consts {
         pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -2494,6 +2574,10 @@ mod consts {
         pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -2714,6 +2798,10 @@ mod consts {
         pub const EOPNOTSUPP: Errno = Errno::ENOTSUP;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -2905,6 +2993,10 @@ mod consts {
         EOPNOTSUPP = libc::EOPNOTSUPP,
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 
@@ -3128,6 +3220,10 @@ mod consts {
         pub const EWOULDBLOCK: Errno = Errno::EAGAIN;
     }
 
+    #[deprecated(
+        since = "0.28.0",
+        note = "please use `Errno::from_raw()` instead"
+    )]
     pub const fn from_i32(e: i32) -> Errno {
         use self::Errno::*;
 

src/fcntl.rs

@@ -1109,7 +1109,7 @@ mod posix_fadvise {
         if res == 0 {
             Ok(())
         } else {
-            Err(Errno::from_i32(res))
+            Err(Errno::from_raw(res))
         }
     }
     }
@@ -1131,7 +1131,7 @@ pub fn posix_fallocate(
     match Errno::result(res) {
         Err(err) => Err(err),
         Ok(0) => Ok(()),
-        Ok(errno) => Err(Errno::from_i32(errno)),
+        Ok(errno) => Err(Errno::from_raw(errno)),
     }
 }
 }

src/sys/aio.rs

@@ -158,7 +158,7 @@ impl AioCb {
         let r = unsafe { libc::aio_error(&self.aiocb().0) };
         match r {
             0 => Ok(()),
-            num if num > 0 => Err(Errno::from_i32(num)),
+            num if num > 0 => Err(Errno::from_raw(num)),
             -1 => Err(Errno::last()),
             num => panic!("unknown aio_error return value {num:?}"),
         }

src/time.rs

@@ -196,7 +196,7 @@ pub fn clock_getcpuclockid(pid: Pid) -> Result<ClockId> {
         let res = unsafe { clk_id.assume_init() };
         Ok(ClockId::from(res))
     } else {
-        Err(Errno::from_i32(ret))
+        Err(Errno::from_raw(ret))
     }
 }
 
@@ -248,6 +248,6 @@ pub fn clock_nanosleep(
     if ret == 0 {
         Ok(remain)
     } else {
-        Err(Errno::from_i32(ret))
+        Err(Errno::from_raw(ret))
     }
 }

src/unistd.rs

@@ -1,6 +1,6 @@
 //! Safe wrappers around functions found in libc "unistd.h" header
 
-use crate::errno::{self, Errno};
+use crate::errno::Errno;
 
 #[cfg(any(
     all(feature = "fs", not(target_os = "redox")),
@@ -2148,7 +2148,7 @@ pub fn fpathconf<F: AsFd>(fd: F, var: PathconfVar) -> Result<Option<c_long>> {
         libc::fpathconf(fd.as_fd().as_raw_fd(), var as c_int)
     };
     if raw == -1 {
-        if errno::errno() == 0 {
+        if Errno::last_raw() == 0 {
             Ok(None)
         } else {
             Err(Errno::last())
@@ -2188,7 +2188,7 @@ pub fn pathconf<P: ?Sized + NixPath>(
         libc::pathconf(cstr.as_ptr(), var as c_int)
     })?;
     if raw == -1 {
-        if errno::errno() == 0 {
+        if Errno::last_raw() == 0 {
             Ok(None)
         } else {
             Err(Errno::last())
@@ -2787,7 +2787,7 @@ pub fn sysconf(var: SysconfVar) -> Result<Option<c_long>> {
         libc::sysconf(var as c_int)
     };
     if raw == -1 {
-        if errno::errno() == 0 {
+        if Errno::last_raw() == 0 {
             Ok(None)
         } else {
             Err(Errno::last())
@@ -3543,7 +3543,7 @@ pub fn ttyname<F: AsFd>(fd: F) -> Result<PathBuf> {
 
     let ret = unsafe { libc::ttyname_r(fd.as_fd().as_raw_fd(), c_buf, buf.len()) };
     if ret != 0 {
-        return Err(Errno::from_i32(ret));
+        return Err(Errno::from_raw(ret));
     }
 
     CStr::from_bytes_until_nul(&buf[..])

test/test.rs

@@ -7,6 +7,7 @@ mod common;
 mod sys;
 #[cfg(not(target_os = "redox"))]
 mod test_dir;
+mod test_errno;
 mod test_fcntl;
 #[cfg(linux_android)]
 mod test_kmod;

test/test_errno.rs

@@ -0,0 +1,8 @@
+use nix::errno::Errno;
+
+#[test]
+fn errno_set_and_read() {
+    Errno::clear();
+    Errno::ENFILE.set();
+    assert_eq!(Errno::last(), Errno::ENFILE);
+}

test/test_mount.rs

@@ -49,7 +49,7 @@ exit 23";
             .mode((Mode::S_IRWXU | Mode::S_IRWXG | Mode::S_IRWXO).bits())
             .open(&test_path)
             .or_else(|e| {
-                if Errno::from_i32(e.raw_os_error().unwrap())
+                if Errno::from_raw(e.raw_os_error().unwrap())
                     == Errno::EOVERFLOW
                 {
                     // Skip tests on certain Linux kernels which have a bug