Auto merge of #293 - dhylands:gettid, r=kamalmarhubi

Add gettid

I tested this under linux, and I noticed that this seems to also be built for OSX. It would be appreciated if someone could test this under OSX.

I'm not familiar enough with rust to know if there is a way of integrating this without creating a sub-crate.

3 files changed, 18 insertions, 1 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 8beb2035..9db0c1df 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -20,7 +20,7 @@ preadv_pwritev = []
 signalfd = []
 
 [dependencies]
-libc     = "0.2.7"
+libc     = "0.2.8"
 bitflags = "0.4"
 cfg-if = "0.1.0"
 
diff --git a/src/unistd.rs b/src/unistd.rs
index 193086df..5d57afd1 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -56,6 +56,12 @@ pub fn setpgid(pid: pid_t, pgid: pid_t) -> Result<()> {
     Errno::result(res).map(drop)
 }
 
+#[cfg(any(target_os = "linux", target_os = "android"))]
+#[inline]
+pub fn gettid() -> pid_t {
+    unsafe { libc::syscall(libc::SYS_gettid) as pid_t }    // no error handling, according to man page: "These functions are always successful."
+}
+
 #[inline]
 pub fn dup(oldfd: RawFd) -> Result<RawFd> {
     let res = unsafe { libc::dup(oldfd) };
diff --git a/test/test_unistd.rs b/test/test_unistd.rs
index 510f8f6c..2f361cfe 100644
--- a/test/test_unistd.rs
+++ b/test/test_unistd.rs
@@ -54,6 +54,17 @@ fn test_getpid() {
     assert!(ppid > 0);
 }
 
+#[cfg(any(target_os = "linux", target_os = "android"))]
+mod linux_android {
+    use nix::unistd::gettid;
+
+    #[test]
+    fn test_gettid() {
+        let tid = gettid();
+        assert!(tid > 0);
+    }
+}
+
 macro_rules! execve_test_factory(
     ($test_name:ident, $syscall:ident, $unix_sh:expr, $android_sh:expr) => (
     #[test]