Avoid mem::uninitialized() in std::sys::unix

For `libc` types that will be initialized in FFI calls, we can just use
`MaybeUninit` and then pass around raw pointers.

For `sun_path_offset()`, which really wants `offset_of`, all callers
have a real `sockaddr_un` available, so we can use that reference.

2 files changed, 34 insertions, 34 deletions

diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
index f6a12a16396..7127386def4 100644
--- a/src/libstd/sys/unix/process/process_common.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -466,11 +466,11 @@ mod tests {
             // Test to make sure that a signal mask does not get inherited.
             let mut cmd = Command::new(OsStr::new("cat"));
 
-            let mut set: libc::sigset_t = mem::uninitialized();
-            let mut old_set: libc::sigset_t = mem::uninitialized();
-            t!(cvt(sigemptyset(&mut set)));
-            t!(cvt(sigaddset(&mut set, libc::SIGINT)));
-            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set, &mut old_set)));
+            let mut set = mem::MaybeUninit::<libc::sigset_t>::uninit();
+            let mut old_set = mem::MaybeUninit::<libc::sigset_t>::uninit();
+            t!(cvt(sigemptyset(set.as_mut_ptr())));
+            t!(cvt(sigaddset(set.as_mut_ptr(), libc::SIGINT)));
+            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, set.as_ptr(), old_set.as_mut_ptr())));
 
             cmd.stdin(Stdio::MakePipe);
             cmd.stdout(Stdio::MakePipe);
@@ -479,7 +479,7 @@ mod tests {
             let stdin_write = pipes.stdin.take().unwrap();
             let stdout_read = pipes.stdout.take().unwrap();
 
-            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &old_set,
+            t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, old_set.as_ptr(),
                                          ptr::null_mut())));
 
             t!(cvt(libc::kill(cat.id() as libc::pid_t, libc::SIGINT)));
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
index 80fe763aecc..28c1d214a8d 100644
--- a/src/libstd/sys/unix/process/process_unix.rs
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -202,7 +202,7 @@ impl Command {
         // emscripten has no signal support.
         #[cfg(not(any(target_os = "emscripten")))]
         {
-            use crate::mem;
+            use crate::mem::{self, MaybeUninit};
             // Reset signal handling so the child process starts in a
             // standardized state. libstd ignores SIGPIPE, and signal-handling
             // libraries often set a mask. Child processes inherit ignored
@@ -210,18 +210,18 @@ impl Command {
             // UNIX programs do not reset these things on their own, so we
             // need to clean things up now to avoid confusing the program
             // we're about to run.
-            let mut set: libc::sigset_t = mem::uninitialized();
+            let mut set = MaybeUninit::<libc::sigset_t>::uninit();
             if cfg!(target_os = "android") {
                 // Implementing sigemptyset allow us to support older Android
                 // versions. See the comment about Android and sig* functions in
                 // process_common.rs
-                libc::memset(&mut set as *mut _ as *mut _,
+                libc::memset(set.as_mut_ptr() as *mut _,
                              0,
                              mem::size_of::<libc::sigset_t>());
             } else {
-                cvt(libc::sigemptyset(&mut set))?;
+                cvt(libc::sigemptyset(set.as_mut_ptr()))?;
             }
-            cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set,
+            cvt(libc::pthread_sigmask(libc::SIG_SETMASK, set.as_ptr(),
                                          ptr::null_mut()))?;
             let ret = sys::signal(libc::SIGPIPE, libc::SIG_DFL);
             if ret == libc::SIG_ERR {
@@ -273,7 +273,7 @@ impl Command {
     fn posix_spawn(&mut self, stdio: &ChildPipes, envp: Option<&CStringArray>)
         -> io::Result<Option<Process>>
     {
-        use crate::mem;
+        use crate::mem::MaybeUninit;
         use crate::sys;
 
         if self.get_gid().is_some() ||
@@ -315,63 +315,63 @@ impl Command {
 
         let mut p = Process { pid: 0, status: None };
 
-        struct PosixSpawnFileActions(libc::posix_spawn_file_actions_t);
+        struct PosixSpawnFileActions(MaybeUninit<libc::posix_spawn_file_actions_t>);
 
         impl Drop for PosixSpawnFileActions {
             fn drop(&mut self) {
                 unsafe {
-                    libc::posix_spawn_file_actions_destroy(&mut self.0);
+                    libc::posix_spawn_file_actions_destroy(self.0.as_mut_ptr());
                 }
             }
         }
 
-        struct PosixSpawnattr(libc::posix_spawnattr_t);
+        struct PosixSpawnattr(MaybeUninit<libc::posix_spawnattr_t>);
 
         impl Drop for PosixSpawnattr {
             fn drop(&mut self) {
                 unsafe {
-                    libc::posix_spawnattr_destroy(&mut self.0);
+                    libc::posix_spawnattr_destroy(self.0.as_mut_ptr());
                 }
             }
         }
 
         unsafe {
-            let mut file_actions = PosixSpawnFileActions(mem::uninitialized());
-            let mut attrs = PosixSpawnattr(mem::uninitialized());
+            let mut file_actions = PosixSpawnFileActions(MaybeUninit::uninit());
+            let mut attrs = PosixSpawnattr(MaybeUninit::uninit());
 
-            libc::posix_spawnattr_init(&mut attrs.0);
-            libc::posix_spawn_file_actions_init(&mut file_actions.0);
+            libc::posix_spawnattr_init(attrs.0.as_mut_ptr());
+            libc::posix_spawn_file_actions_init(file_actions.0.as_mut_ptr());
 
             if let Some(fd) = stdio.stdin.fd() {
-                cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
+                cvt(libc::posix_spawn_file_actions_adddup2(file_actions.0.as_mut_ptr(),
                                                            fd,
                                                            libc::STDIN_FILENO))?;
             }
             if let Some(fd) = stdio.stdout.fd() {
-                cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
+                cvt(libc::posix_spawn_file_actions_adddup2(file_actions.0.as_mut_ptr(),
                                                            fd,
                                                            libc::STDOUT_FILENO))?;
             }
             if let Some(fd) = stdio.stderr.fd() {
-                cvt(libc::posix_spawn_file_actions_adddup2(&mut file_actions.0,
+                cvt(libc::posix_spawn_file_actions_adddup2(file_actions.0.as_mut_ptr(),
                                                            fd,
                                                            libc::STDERR_FILENO))?;
             }
             if let Some((f, cwd)) = addchdir {
-                cvt(f(&mut file_actions.0, cwd.as_ptr()))?;
+                cvt(f(file_actions.0.as_mut_ptr(), cwd.as_ptr()))?;
             }
 
-            let mut set: libc::sigset_t = mem::uninitialized();
-            cvt(libc::sigemptyset(&mut set))?;
-            cvt(libc::posix_spawnattr_setsigmask(&mut attrs.0,
-                                                 &set))?;
-            cvt(libc::sigaddset(&mut set, libc::SIGPIPE))?;
-            cvt(libc::posix_spawnattr_setsigdefault(&mut attrs.0,
-                                                    &set))?;
+            let mut set = MaybeUninit::<libc::sigset_t>::uninit();
+            cvt(libc::sigemptyset(set.as_mut_ptr()))?;
+            cvt(libc::posix_spawnattr_setsigmask(attrs.0.as_mut_ptr(),
+                                                 set.as_ptr()))?;
+            cvt(libc::sigaddset(set.as_mut_ptr(), libc::SIGPIPE))?;
+            cvt(libc::posix_spawnattr_setsigdefault(attrs.0.as_mut_ptr(),
+                                                    set.as_ptr()))?;
 
             let flags = libc::POSIX_SPAWN_SETSIGDEF |
                 libc::POSIX_SPAWN_SETSIGMASK;
-            cvt(libc::posix_spawnattr_setflags(&mut attrs.0, flags as _))?;
+            cvt(libc::posix_spawnattr_setflags(attrs.0.as_mut_ptr(), flags as _))?;
 
             // Make sure we synchronize access to the global `environ` resource
             let _env_lock = sys::os::env_lock();
@@ -380,8 +380,8 @@ impl Command {
             let ret = libc::posix_spawnp(
                 &mut p.pid,
                 self.get_argv()[0],
-                &file_actions.0,
-                &attrs.0,
+                file_actions.0.as_ptr(),
+                attrs.0.as_ptr(),
                 self.get_argv().as_ptr() as *const _,
                 envp as *const _,
             );