Add gettid

Cargo.toml

@@ -22,12 +22,14 @@ signalfd = []
 [dependencies]
 libc     = "0.2.7"
 bitflags = "0.4"
+c-nix    = { path = "c-nix", version = "0.1" }
 
 [dev-dependencies]
 rand = "0.3.8"
 tempdir = "0.3"
 tempfile = "2"
 nix-test = { path = "nix-test" }
+c-nix    = { path = "c-nix", version = "0.1" }
 
 [[test]]
 name = "test"

c-nix/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "c-nix"
+version = "0.1.0"
+authors = ["Dave Hylands <dhylands@gmail.com>"]
+build = "build.rs"
+
+[dependencies]
+libc = "0.2.7"
+
+[build-dependencies]
+gcc = "0.3.8"

c-nix/build.rs

@@ -0,0 +1,10 @@
+extern crate gcc;
+
+fn main() {
+    let mut c = gcc::Config::new();
+    let config = c.file("c-src/gettid.c")
+     .cpp(false);
+
+    config.compile("libc-nix.a");
+    println!("cargo:rustc-flags=-l c-nix");
+}

c-nix/c-src/gettid.c

@@ -0,0 +1,12 @@
+#include <sys/syscall.h>
+
+// SYS_gettid has different values on different platforms, so we let the
+// C preprocessor figure things out for us.
+
+int c_gettid(void) {
+#if defined(__APPLE__)
+    return syscall(SYS_thread_selfid);
+#else
+    return syscall(SYS_gettid);
+#endif
+}

c-nix/src/lib.rs

@@ -0,0 +1,17 @@
+extern crate libc;
+
+extern {
+    pub fn c_gettid() -> libc::pid_t;
+}
+
+pub fn gettid() -> libc::pid_t {
+    unsafe { c_gettid() }
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    fn it_works() {
+        println!("gettid() = {}", gettid());
+    }
+}

nix-test/Cargo.toml

@@ -10,6 +10,7 @@ license     = "MIT"
 
 [dependencies]
 libc = "*"
+c-nix    = { path = "../c-nix", version = "0.1" }
 
 [build-dependencies]
 gcc = "0.3.8"

nix-test/src/lib.rs

@@ -8,6 +8,7 @@ mod ffi {
     use libc::{c_int, c_char, size_t};
 
     #[link(name = "nixtest", kind = "static")]
+    #[link(name = "c-nix", kind = "static")]
     extern {
         pub fn get_int_const(errno: *const c_char) -> c_int;
         pub fn size_of(ty: *const c_char) -> size_t;

src/unistd.rs

@@ -112,6 +112,14 @@ pub fn setpgid(pid: pid_t, pgid: pid_t) -> Result<()> {
     Errno::result(res).map(drop)
 }
 
+extern {
+    pub fn c_gettid() -> pid_t;
+}
+#[inline]
+pub fn gettid() -> pid_t {
+    unsafe { c_gettid() }    // no error handling, according to man page: "These functions are always successful."
+}
+
 #[inline]
 pub fn dup(oldfd: RawFd) -> Result<RawFd> {
     let res = unsafe { ffi::dup(oldfd) };

test/test_unistd.rs

@@ -50,8 +50,10 @@ fn test_wait() {
 fn test_getpid() {
     let pid = getpid();
     let ppid = getppid();
+    let tid = gettid();
     assert!(pid > 0);
     assert!(ppid > 0);
+    assert!(tid > 0);
 }
 
 macro_rules! execve_test_factory(