Rollup merge of #40317 - malbarbo:update-libc, r=alexcrichton

Update libc to 0.2.21

Update to include android aarch64 and x86 improvements.

3 files changed, 27 insertions, 4 deletions

diff --git a/src/libstd/sys/unix/ext/net.rs b/src/libstd/sys/unix/ext/net.rs
index 55118829eee..d688f2fa504 100644
--- a/src/libstd/sys/unix/ext/net.rs
+++ b/src/libstd/sys/unix/ext/net.rs
@@ -641,7 +641,7 @@ impl UnixListener {
                 let inner = Socket::new_raw(libc::AF_UNIX, libc::SOCK_STREAM)?;
                 let (addr, len) = sockaddr_un(path)?;
 
-                cvt(libc::bind(*inner.as_inner(), &addr as *const _ as *const _, len))?;
+                cvt(libc::bind(*inner.as_inner(), &addr as *const _ as *const _, len as _))?;
                 cvt(libc::listen(*inner.as_inner(), 128))?;
 
                 Ok(UnixListener(inner))
@@ -920,7 +920,7 @@ impl UnixDatagram {
                 let socket = UnixDatagram::unbound()?;
                 let (addr, len) = sockaddr_un(path)?;
 
-                cvt(libc::bind(*socket.0.as_inner(), &addr as *const _ as *const _, len))?;
+                cvt(libc::bind(*socket.0.as_inner(), &addr as *const _ as *const _, len as _))?;
 
                 Ok(socket)
             }
diff --git a/src/libstd/sys/unix/process/process_common.rs b/src/libstd/sys/unix/process/process_common.rs
index 5f1a6c2f746..e9f41009064 100644
--- a/src/libstd/sys/unix/process/process_common.rs
+++ b/src/libstd/sys/unix/process/process_common.rs
@@ -417,13 +417,27 @@ mod tests {
         }
     }
 
+    // Android with api less than 21 define sig* functions inline, so it is not
+    // available for dynamic link. Implementing sigemptyset and sigaddset allow us
+    // to support older Android version (independent of libc version).
+    // The following implementations are based on https://git.io/vSkNf
+
     #[cfg(not(target_os = "android"))]
     extern {
+        #[cfg_attr(target_os = "netbsd", link_name = "__sigemptyset14")]
+        fn sigemptyset(set: *mut libc::sigset_t) -> libc::c_int;
+
         #[cfg_attr(target_os = "netbsd", link_name = "__sigaddset14")]
         fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int;
     }
 
     #[cfg(target_os = "android")]
+    unsafe fn sigemptyset(set: *mut libc::sigset_t) -> libc::c_int {
+        libc::memset(set as *mut _, 0, mem::size_of::<libc::sigset_t>());
+        return 0;
+    }
+
+    #[cfg(target_os = "android")]
     unsafe fn sigaddset(set: *mut libc::sigset_t, signum: libc::c_int) -> libc::c_int {
         use slice;
 
@@ -450,7 +464,7 @@ mod tests {
 
             let mut set: libc::sigset_t = mem::uninitialized();
             let mut old_set: libc::sigset_t = mem::uninitialized();
-            t!(cvt(libc::sigemptyset(&mut set)));
+            t!(cvt(sigemptyset(&mut set)));
             t!(cvt(sigaddset(&mut set, libc::SIGINT)));
             t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set, &mut old_set)));
 
diff --git a/src/libstd/sys/unix/process/process_unix.rs b/src/libstd/sys/unix/process/process_unix.rs
index a213273aac8..edd322ca6fa 100644
--- a/src/libstd/sys/unix/process/process_unix.rs
+++ b/src/libstd/sys/unix/process/process_unix.rs
@@ -193,7 +193,16 @@ impl Command {
             // need to clean things up now to avoid confusing the program
             // we're about to run.
             let mut set: libc::sigset_t = mem::uninitialized();
-            t!(cvt(libc::sigemptyset(&mut set)));
+            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 _,
+                             0,
+                             mem::size_of::<libc::sigset_t>());
+            } else {
+                t!(cvt(libc::sigemptyset(&mut set)));
+            }
             t!(cvt(libc::pthread_sigmask(libc::SIG_SETMASK, &set,
                                          ptr::null_mut())));
             let ret = sys::signal(libc::SIGPIPE, libc::SIG_DFL);