Fix multiprocessing closesocket, set_errno (#6388)

* Fix multiprocessing closesocket

* set_errno

Cargo.lock

@@ -3007,6 +3007,7 @@ dependencies = [
  "malachite-base",
  "malachite-bigint",
  "malachite-q",
+ "nix 0.30.1",
  "num-complex",
  "num-traits",
  "once_cell",

crates/common/Cargo.toml

@@ -35,6 +35,9 @@ lock_api = "0.4"
 siphasher = "1"
 num-complex.workspace = true
 
+[target.'cfg(unix)'.dependencies]
+nix = { workspace = true }
+
 [target.'cfg(windows)'.dependencies]
 widestring = { workspace = true }
 windows-sys = { workspace = true, features = [

crates/common/src/os.rs

@@ -48,6 +48,20 @@ pub fn get_errno() -> i32 {
     std::io::Error::last_os_error().posix_errno()
 }
 
+/// Set errno to the specified value.
+#[cfg(windows)]
+pub fn set_errno(value: i32) {
+    unsafe extern "C" {
+        fn _set_errno(value: i32) -> i32;
+    }
+    unsafe { suppress_iph!(_set_errno(value)) };
+}
+
+#[cfg(unix)]
+pub fn set_errno(value: i32) {
+    nix::errno::Errno::from_raw(value).set();
+}
+
 #[cfg(unix)]
 pub fn bytes_as_os_str(b: &[u8]) -> Result<&std::ffi::OsStr, Utf8Error> {
     use std::os::unix::ffi::OsStrExt;

crates/stdlib/src/multiprocessing.rs

@@ -9,7 +9,7 @@ mod _multiprocessing {
     #[pyfunction]
     fn closesocket(socket: usize, vm: &VirtualMachine) -> PyResult<()> {
         let res = unsafe { WinSock::closesocket(socket as SOCKET) };
-        if res == 0 {
+        if res != 0 {
             Err(vm.new_last_os_error())
         } else {
             Ok(())

crates/stdlib/src/socket.rs

@@ -2143,10 +2143,11 @@ mod _socket {
     #[pyfunction]
     fn if_nametoindex(name: FsPath, vm: &VirtualMachine) -> PyResult<IfIndex> {
         let name = name.to_cstring(vm)?;
-
+        // in case 'if_nametoindex' does not set errno
+        crate::common::os::set_errno(libc::ENODEV);
         let ret = unsafe { c::if_nametoindex(name.as_ptr() as _) };
         if ret == 0 {
-            Err(vm.new_os_error("no interface with this name".to_owned()))
+            Err(vm.new_last_errno_error())
         } else {
             Ok(ret)
         }
@@ -2156,6 +2157,8 @@ mod _socket {
     #[pyfunction]
     fn if_indextoname(index: IfIndex, vm: &VirtualMachine) -> PyResult<String> {
         let mut buf = [0; c::IF_NAMESIZE + 1];
+        // in case 'if_indextoname' does not set errno
+        crate::common::os::set_errno(libc::ENXIO);
         let ret = unsafe { c::if_indextoname(index, buf.as_mut_ptr()) };
         if ret.is_null() {
             Err(vm.new_last_errno_error())

crates/vm/src/stdlib/posix.rs

@@ -2337,8 +2337,9 @@ pub mod module {
 
     #[pyfunction]
     fn sysconf(name: SysconfName, vm: &VirtualMachine) -> PyResult<libc::c_long> {
+        crate::common::os::set_errno(0);
         let r = unsafe { libc::sysconf(name.0) };
-        if r == -1 {
+        if r == -1 && crate::common::os::get_errno() != 0 {
             return Err(vm.new_last_errno_error());
         }
         Ok(r)