Auto merge of #34441 - tbu-:pr_dont_ignore_errors, r=alexcrichton

Don't ignore errors of syscalls in std::sys::unix::fd

If any of these syscalls fail, it indicates a programmer error that
should not be silently ignored.

Author: bors

src/libstd/sys/unix/fd.rs

@@ -62,32 +62,31 @@ impl FileDesc {
     }
 
     #[cfg(not(any(target_env = "newlib", target_os = "solaris", target_os = "emscripten")))]
-    pub fn set_cloexec(&self) {
+    pub fn set_cloexec(&self) -> io::Result<()> {
         unsafe {
-            let ret = libc::ioctl(self.fd, libc::FIOCLEX);
-            debug_assert_eq!(ret, 0);
+            cvt(libc::ioctl(self.fd, libc::FIOCLEX))?;
+            Ok(())
         }
     }
     #[cfg(any(target_env = "newlib", target_os = "solaris", target_os = "emscripten"))]
-    pub fn set_cloexec(&self) {
+    pub fn set_cloexec(&self) -> io::Result<()> {
         unsafe {
-            let previous = libc::fcntl(self.fd, libc::F_GETFD);
-            let ret = libc::fcntl(self.fd, libc::F_SETFD, previous | libc::FD_CLOEXEC);
-            debug_assert_eq!(ret, 0);
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFD))?;
+            cvt(libc::fcntl(self.fd, libc::F_SETFD, previous | libc::FD_CLOEXEC))?;
+            Ok(())
         }
     }
 
-    pub fn set_nonblocking(&self, nonblocking: bool) {
+    pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
         unsafe {
-            let previous = libc::fcntl(self.fd, libc::F_GETFL);
-            debug_assert!(previous != -1);
+            let previous = cvt(libc::fcntl(self.fd, libc::F_GETFL))?;
             let new = if nonblocking {
                 previous | libc::O_NONBLOCK
             } else {
                 previous & !libc::O_NONBLOCK
             };
-            let ret = libc::fcntl(self.fd, libc::F_SETFL, new);
-            debug_assert!(ret != -1);
+            cvt(libc::fcntl(self.fd, libc::F_SETFL, new))?;
+            Ok(())
         }
     }
 
@@ -114,8 +113,8 @@ impl FileDesc {
 
         let make_filedesc = |fd| {
             let fd = FileDesc::new(fd);
-            fd.set_cloexec();
-            fd
+            fd.set_cloexec()?;
+            Ok(fd)
         };
         static TRY_CLOEXEC: AtomicBool =
             AtomicBool::new(!cfg!(target_os = "android"));
@@ -127,7 +126,7 @@ impl FileDesc {
                 // though it reported doing so on F_DUPFD_CLOEXEC.
                 Ok(fd) => {
                     return Ok(if cfg!(target_os = "linux") {
-                        make_filedesc(fd)
+                        make_filedesc(fd)?
                     } else {
                         FileDesc::new(fd)
                     })
@@ -138,7 +137,7 @@ impl FileDesc {
                 Err(e) => return Err(e),
             }
         }
-        cvt(unsafe { libc::fcntl(fd, libc::F_DUPFD, 0) }).map(make_filedesc)
+        cvt(unsafe { libc::fcntl(fd, libc::F_DUPFD, 0) }).and_then(make_filedesc)
     }
 }
 

src/libstd/sys/unix/fs.rs

@@ -418,7 +418,7 @@ impl File {
         // The CLOEXEC flag, however, is supported on versions of OSX/BSD/etc
         // that we support, so we only do this on Linux currently.
         if cfg!(target_os = "linux") {
-            fd.set_cloexec();
+            fd.set_cloexec()?;
         }
 
         Ok(File(fd))

src/libstd/sys/unix/net.rs

@@ -77,7 +77,7 @@ impl Socket {
 
             let fd = cvt(libc::socket(fam, ty, 0))?;
             let fd = FileDesc::new(fd);
-            fd.set_cloexec();
+            fd.set_cloexec()?;
             Ok(Socket(fd))
         }
     }
@@ -99,9 +99,9 @@ impl Socket {
 
             cvt(libc::socketpair(fam, ty, 0, fds.as_mut_ptr()))?;
             let a = FileDesc::new(fds[0]);
-            a.set_cloexec();
             let b = FileDesc::new(fds[1]);
-            b.set_cloexec();
+            a.set_cloexec()?;
+            b.set_cloexec()?;
             Ok((Socket(a), Socket(b)))
         }
     }
@@ -132,7 +132,7 @@ impl Socket {
             libc::accept(self.0.raw(), storage, len)
         })?;
         let fd = FileDesc::new(fd);
-        fd.set_cloexec();
+        fd.set_cloexec()?;
         Ok(Socket(fd))
     }
 

src/libstd/sys/unix/pipe.rs

@@ -44,17 +44,18 @@ pub fn anon_pipe() -> io::Result<(AnonPipe, AnonPipe)> {
         }
     }
     if unsafe { libc::pipe(fds.as_mut_ptr()) == 0 } {
-        Ok((AnonPipe::from_fd(fds[0]), AnonPipe::from_fd(fds[1])))
+        let fd0 = FileDesc::new(fds[0]);
+        let fd1 = FileDesc::new(fds[1]);
+        Ok((AnonPipe::from_fd(fd0)?, AnonPipe::from_fd(fd1)?))
     } else {
         Err(io::Error::last_os_error())
     }
 }
 
 impl AnonPipe {
-    pub fn from_fd(fd: libc::c_int) -> AnonPipe {
-        let fd = FileDesc::new(fd);
-        fd.set_cloexec();
-        AnonPipe(fd)
+    pub fn from_fd(fd: FileDesc) -> io::Result<AnonPipe> {
+        fd.set_cloexec()?;
+        Ok(AnonPipe(fd))
     }
 
     pub fn read(&self, buf: &mut [u8]) -> io::Result<usize> {
@@ -81,8 +82,8 @@ pub fn read2(p1: AnonPipe,
     // in the `select` loop below, and we wouldn't want one to block the other!
     let p1 = p1.into_fd();
     let p2 = p2.into_fd();
-    p1.set_nonblocking(true);
-    p2.set_nonblocking(true);
+    p1.set_nonblocking(true)?;
+    p2.set_nonblocking(true)?;
 
     let max = cmp::max(p1.raw(), p2.raw());
     loop {
@@ -114,11 +115,11 @@ pub fn read2(p1: AnonPipe,
             }
         };
         if read(&p1, v1)? {
-            p2.set_nonblocking(false);
+            p2.set_nonblocking(false)?;
             return p2.read_to_end(v2).map(|_| ());
         }
         if read(&p2, v2)? {
-            p1.set_nonblocking(false);
+            p1.set_nonblocking(false)?;
             return p1.read_to_end(v1).map(|_| ());
         }
     }