From 93450abb4bf6a755b343ca459bbeff92540a7822 Mon Sep 17 00:00:00 2001
From: Graydon Hoare <graydon@mozilla.com>
Date: Tue, 7 Feb 2012 18:55:02 -0800
Subject: [PATCH] Make process-spawning take environments and working
 directories, remove procsrv task from compiletest.

---
 src/compiletest/common.rs      |   2 -
 src/compiletest/compiletest.rs |  39 ++-----
 src/compiletest/procsrv.rs     | 196 +++++++--------------------------
 src/compiletest/runtest.rs     |  85 +++++++-------
 src/libcore/str.rs             |  14 +--
 src/libcore/vec.rs             |  12 ++
 src/libstd/freebsd_os.rs       |   2 +
 src/libstd/generic_os.rs       |  22 ++--
 src/libstd/linux_os.rs         |   2 +
 src/libstd/macos_os.rs         |   2 +
 src/libstd/run_program.rs      | 123 ++++++++++++++++-----
 src/libstd/test.rs             |  11 +-
 src/libstd/win32_os.rs         |   1 +
 src/rt/rust.cpp                |  11 +-
 src/rt/rust_builtin.cpp        |  47 ++++++++
 src/rt/rust_run_program.cpp    |  29 ++++-
 src/rt/rust_util.h             |  15 +++
 src/rt/rustrt.def.in           |   1 +
 18 files changed, 328 insertions(+), 286 deletions(-)

diff --git a/src/compiletest/common.rs b/src/compiletest/common.rs
index bb5e629ef62..7f2c46bef48 100644
--- a/src/compiletest/common.rs
+++ b/src/compiletest/common.rs
@@ -28,5 +28,3 @@ type config =
      runtool: option<str>,
      rustcflags: option<str>,
      verbose: bool};
-
-type cx = {config: config, procsrv: procsrv::handle};
diff --git a/src/compiletest/compiletest.rs b/src/compiletest/compiletest.rs
index 32f8762577f..4fc510e9c62 100644
--- a/src/compiletest/compiletest.rs
+++ b/src/compiletest/compiletest.rs
@@ -17,7 +17,6 @@ import comm::chan;
 import comm::send;
 import comm::recv;
 
-import common::cx;
 import common::config;
 import common::mode_run_pass;
 import common::mode_run_fail;
@@ -113,10 +112,8 @@ fn mode_str(mode: mode) -> str {
 
 fn run_tests(config: config) {
     let opts = test_opts(config);
-    let cx = {config: config, procsrv: procsrv::mk()};
-    let tests = make_tests(cx);
+    let tests = make_tests(config);
     let res = test::run_tests_console(opts, tests);
-    procsrv::close(cx.procsrv);
     if !res { fail "Some tests failed"; }
 }
 
@@ -129,14 +126,14 @@ fn test_opts(config: config) -> test::test_opts {
      run_ignored: config.run_ignored}
 }
 
-fn make_tests(cx: cx) -> [test::test_desc] {
-    #debug("making tests from %s", cx.config.src_base);
+fn make_tests(config: config) -> [test::test_desc] {
+    #debug("making tests from %s", config.src_base);
     let tests = [];
-    for file: str in fs::list_dir(cx.config.src_base) {
+    for file: str in fs::list_dir(config.src_base) {
         let file = file;
         #debug("inspecting file %s", file);
-        if is_test(cx.config, file) {
-            tests += [make_test(cx, file)]
+        if is_test(config, file) {
+            tests += [make_test(config, file)]
         }
     }
     ret tests;
@@ -162,12 +159,12 @@ fn is_test(config: config, testfile: str) -> bool {
     ret valid;
 }
 
-fn make_test(cx: cx, testfile: str) ->
+fn make_test(config: config, testfile: str) ->
    test::test_desc {
     {
-        name: make_test_name(cx.config, testfile),
-        fn: make_test_closure(cx, testfile),
-        ignore: header::is_test_ignored(cx.config, testfile),
+        name: make_test_name(config, testfile),
+        fn: make_test_closure(config, testfile),
+        ignore: header::is_test_ignored(config, testfile),
         should_fail: false
     }
 }
@@ -176,24 +173,12 @@ fn make_test_name(config: config, testfile: str) -> str {
     #fmt["[%s] %s", mode_str(config.mode), testfile]
 }
 
-fn make_test_closure(cx: cx, testfile: str) -> test::test_fn {
-    let config = cx.config;
-    let chan = cx.procsrv.chan;
+fn make_test_closure(config: config, testfile: str) -> test::test_fn {
     ret {||
-        run_test_task(config, chan, testfile);
+        runtest::run(config, copy testfile);
     };
 }
 
-fn run_test_task(config: common::config,
-                 procsrv_chan: procsrv::reqchan,
-                 testfile: str) {
-
-    let procsrv = procsrv::from_chan(procsrv_chan);
-    let cx = {config: config, procsrv: procsrv};
-
-    runtest::run(cx, copy testfile);
-}
-
 // Local Variables:
 // fill-column: 78;
 // indent-tabs-mode: nil
diff --git a/src/compiletest/procsrv.rs b/src/compiletest/procsrv.rs
index 4d01d299548..892ed15fb33 100644
--- a/src/compiletest/procsrv.rs
+++ b/src/compiletest/procsrv.rs
@@ -1,71 +1,60 @@
-// So when running tests in parallel there's a potential race on environment
-// variables if we let each task spawn its own children - between the time the
-// environment is set and the process is spawned another task could spawn its
-// child process. Because of that we have to use a complicated scheme with a
-// dedicated server for spawning processes.
-
-import std::generic_os::setenv;
-import std::generic_os::getenv;
-import std::os;
 import std::run;
+import std::run::spawn_process;
 import std::io;
+import std::os;
 import io::writer_util;
-import comm::chan;
-import comm::port;
-import comm::send;
-import comm::recv;
 import ctypes::{pid_t, fd_t};
 
-export handle;
-export mk;
-export from_chan;
 export run;
-export close;
-export reqchan;
 
-type reqchan = chan<request>;
+#[cfg(target_os = "win32")]
+fn target_env(lib_path: str, prog: str) -> option<[(str,str)]> {
 
-type handle =
-    {task: option<(task::task, port<task::task_notification>)>,
-     chan: reqchan};
+    let env = std::generic_os::env();
 
-enum request { exec([u8], [u8], [[u8]], chan<response>), stop, }
-
-type response = {pid: pid_t, infd: fd_t,
-                 outfd: fd_t, errfd: fd_t};
-
-fn mk() -> handle {
-    let setupport = port();
-    let setupchan = chan(setupport);
-    let task = task::spawn_joinable {||
-        let reqport = port();
-        let reqchan = chan(reqport);
-        send(setupchan, reqchan);
-        worker(reqport);
+    env = vec::map(env) {|pair|
+        let (k,v) = pair;
+        if k == "PATH" { ("PATH", v + ";" + lib_path) }
+        else { (k,v) }
     };
-    ret {task: option::some(task), chan: recv(setupport)};
+    if str::ends_with(prog, "rustc.exe") {
+        env += [("RUST_THREADS", "1")]
+    }
+    ret some(env);
 }
 
-fn from_chan(ch: reqchan) -> handle { {task: option::none, chan: ch} }
-
-fn close(handle: handle) {
-    send(handle.chan, stop);
-    task::join(option::get(handle.task));
+#[cfg(target_os = "linux")]
+#[cfg(target_os = "macos")]
+#[cfg(target_os = "freebsd")]
+fn target_env(lib_path: str, prog: str) -> option<[(str,str)]> {
+    none
 }
 
-fn run(handle: handle, lib_path: str, prog: str, args: [str],
+
+fn run(lib_path: str, prog: str, args: [str],
        input: option<str>) -> {status: int, out: str, err: str} {
-    let p = port();
-    let ch = chan(p);
-    send(handle.chan,
-         exec(str::bytes(lib_path), str::bytes(prog), clone_vecstr(args),
-              ch));
-    let resp = recv(p);
 
-    writeclose(resp.infd, input);
-    let output = readclose(resp.outfd);
-    let errput = readclose(resp.errfd);
-    let status = run::waitpid(resp.pid);
+    let pipe_in = os::pipe();
+    let pipe_out = os::pipe();
+    let pipe_err = os::pipe();
+    let pid = spawn_process(prog, args, target_env(lib_path, prog), none,
+                            pipe_in.in, pipe_out.out, pipe_err.out);
+
+    os::close(pipe_in.in);
+    os::close(pipe_out.out);
+    os::close(pipe_err.out);
+    if pid == -1i32 {
+        os::close(pipe_in.out);
+        os::close(pipe_out.in);
+        os::close(pipe_err.in);
+        fail;
+    }
+
+
+    writeclose(pipe_in.out, input);
+    let output = readclose(pipe_out.in);
+    let errput = readclose(pipe_err.in);
+    let status = run::waitpid(pid);
     ret {status: status, out: output, err: errput};
 }
 
@@ -90,106 +79,3 @@ fn readclose(fd: fd_t) -> str {
     os::fclose(file);
     ret buf;
 }
-
-fn worker(p: port<request>) {
-
-    // FIXME (787): If we declare this inside of the while loop and then
-    // break out of it before it's ever initialized (i.e. we don't run
-    // any tests), then the cleanups will puke.
-    let execparms;
-
-    while true {
-        // FIXME: Sending strings across channels seems to still
-        // leave them refed on the sender's end, which causes problems if
-        // the receiver's poniters outlive the sender's. Here we clone
-        // everything and let the originals go out of scope before sending
-        // a response.
-        execparms =
-            {
-
-                // FIXME (785): The 'discriminant' of an alt expression has
-                // the same scope as the alt expression itself, so we have to
-                // put the entire alt in another block to make sure the exec
-                // message goes out of scope. Seems like the scoping rules for
-                // the alt discriminant are wrong.
-                alt recv(p) {
-                  exec(lib_path, prog, args, respchan) {
-                    {lib_path: str::from_bytes(lib_path),
-                     prog: str::from_bytes(prog),
-                     args: clone_vecu8str(args),
-                     respchan: respchan}
-                  }
-                  stop { ret }
-                }
-            };
-
-        // This is copied from run::start_program
-        let pipe_in = os::pipe();
-        let pipe_out = os::pipe();
-        let pipe_err = os::pipe();
-        let spawnproc =
-            bind run::spawn_process(execparms.prog, execparms.args,
-                                    pipe_in.in, pipe_out.out, pipe_err.out);
-        let pid = maybe_with_lib_path(execparms.lib_path, spawnproc);
-
-        os::close(pipe_in.in);
-        os::close(pipe_out.out);
-        os::close(pipe_err.out);
-        if pid == -1i32 {
-            os::close(pipe_in.out);
-            os::close(pipe_out.in);
-            os::close(pipe_err.in);
-            fail;
-        }
-
-        send(execparms.respchan,
-             {pid: pid,
-              infd: pipe_in.out,
-              outfd: pipe_out.in,
-              errfd: pipe_err.in});
-    }
-}
-
-// Only windows needs to set the library path
-#[cfg(target_os = "win32")]
-fn maybe_with_lib_path<T>(path: str, f: fn@() -> T) -> T {
-    with_lib_path(path, f)
-}
-
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "freebsd")]
-fn maybe_with_lib_path<T>(_path: str, f: fn@() -> T) -> T {
-    f()
-}
-
-fn with_lib_path<T>(path: str, f: fn@() -> T) -> T {
-    let maybe_oldpath = getenv(util::lib_path_env_var());
-    append_lib_path(path);
-    let res = f();
-    if option::is_some(maybe_oldpath) {
-        export_lib_path(option::get(maybe_oldpath));
-    } else {
-        // FIXME: This should really be unset but we don't have that yet
-        export_lib_path("");
-    }
-    ret res;
-}
-
-fn append_lib_path(path: str) { export_lib_path(util::make_new_path(path)); }
-
-fn export_lib_path(path: str) { setenv(util::lib_path_env_var(), path); }
-
-fn clone_vecstr(v: [str]) -> [[u8]] {
-    let r = [];
-    for t: str in vec::slice(v, 0u, vec::len(v)) { r += [str::bytes(t)]; }
-    ret r;
-}
-
-fn clone_vecu8str(v: [[u8]]) -> [str] {
-    let r = [];
-    for t in vec::slice(v, 0u, vec::len(v)) {
-        r += [str::from_bytes(t)];
-    }
-    ret r;
-}
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 375625fc794..68b821bc1c9 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -7,7 +7,6 @@ import common::mode_run_pass;
 import common::mode_run_fail;
 import common::mode_compile_fail;
 import common::mode_pretty;
-import common::cx;
 import common::config;
 import header::load_props;
 import header::test_props;
@@ -15,23 +14,23 @@ import util::logv;
 
 export run;
 
-fn run(cx: cx, testfile: str) {
-    if cx.config.verbose {
+fn run(config: config, testfile: str) {
+    if config.verbose {
         // We're going to be dumping a lot of info. Start on a new line.
         io::stdout().write_str("\n\n");
     }
     #debug("running %s", testfile);
     let props = load_props(testfile);
-    alt cx.config.mode {
-      mode_compile_fail { run_cfail_test(cx, props, testfile); }
-      mode_run_fail { run_rfail_test(cx, props, testfile); }
-      mode_run_pass { run_rpass_test(cx, props, testfile); }
-      mode_pretty { run_pretty_test(cx, props, testfile); }
+    alt config.mode {
+      mode_compile_fail { run_cfail_test(config, props, testfile); }
+      mode_run_fail { run_rfail_test(config, props, testfile); }
+      mode_run_pass { run_rpass_test(config, props, testfile); }
+      mode_pretty { run_pretty_test(config, props, testfile); }
     }
 }
 
-fn run_cfail_test(cx: cx, props: test_props, testfile: str) {
-    let procres = compile_test(cx, props, testfile);
+fn run_cfail_test(config: config, props: test_props, testfile: str) {
+    let procres = compile_test(config, props, testfile);
 
     if procres.status == 0 {
         fatal_procres("compile-fail test compiled successfully!", procres);
@@ -50,12 +49,12 @@ fn run_cfail_test(cx: cx, props: test_props, testfile: str) {
     }
 }
 
-fn run_rfail_test(cx: cx, props: test_props, testfile: str) {
-    let procres = compile_test(cx, props, testfile);
+fn run_rfail_test(config: config, props: test_props, testfile: str) {
+    let procres = compile_test(config, props, testfile);
 
     if procres.status != 0 { fatal_procres("compilation failed!", procres); }
 
-    procres = exec_compiled_test(cx, props, testfile);
+    procres = exec_compiled_test(config, props, testfile);
 
     // The value our Makefile configures valgrind to return on failure
     const valgrind_err: int = 100;
@@ -78,21 +77,21 @@ fn check_correct_failure_status(procres: procres) {
     }
 }
 
-fn run_rpass_test(cx: cx, props: test_props, testfile: str) {
-    let procres = compile_test(cx, props, testfile);
+fn run_rpass_test(config: config, props: test_props, testfile: str) {
+    let procres = compile_test(config, props, testfile);
 
     if procres.status != 0 { fatal_procres("compilation failed!", procres); }
 
-    procres = exec_compiled_test(cx, props, testfile);
+    procres = exec_compiled_test(config, props, testfile);
 
 
     if procres.status != 0 { fatal_procres("test run failed!", procres); }
 }
 
-fn run_pretty_test(cx: cx, props: test_props, testfile: str) {
+fn run_pretty_test(config: config, props: test_props, testfile: str) {
     if option::is_some(props.pp_exact) {
-        logv(cx.config, "testing for exact pretty-printing");
-    } else { logv(cx.config, "testing for converging pretty-printing"); }
+        logv(config, "testing for exact pretty-printing");
+    } else { logv(config, "testing for converging pretty-printing"); }
 
     let rounds =
         alt props.pp_exact { option::some(_) { 1 } option::none { 2 } };
@@ -101,8 +100,8 @@ fn run_pretty_test(cx: cx, props: test_props, testfile: str) {
 
     let round = 0;
     while round < rounds {
-        logv(cx.config, #fmt["pretty-printing round %d", round]);
-        let procres = print_source(cx, testfile, srcs[round]);
+        logv(config, #fmt["pretty-printing round %d", round]);
+        let procres = print_source(config, testfile, srcs[round]);
 
         if procres.status != 0 {
             fatal_procres(#fmt["pretty-printing failed in round %d", round],
@@ -134,7 +133,7 @@ fn run_pretty_test(cx: cx, props: test_props, testfile: str) {
     compare_source(expected, actual);
 
     // Finally, let's make sure it actually appears to remain valid code
-    let procres = typecheck_source(cx, testfile, actual);
+    let procres = typecheck_source(config, testfile, actual);
 
     if procres.status != 0 {
         fatal_procres("pretty-printed source does not typecheck", procres);
@@ -142,9 +141,9 @@ fn run_pretty_test(cx: cx, props: test_props, testfile: str) {
 
     ret;
 
-    fn print_source(cx: cx, testfile: str, src: str) -> procres {
-        compose_and_run(cx, testfile, make_pp_args,
-                        cx.config.compile_lib_path, option::some(src))
+    fn print_source(config: config, testfile: str, src: str) -> procres {
+        compose_and_run(config, testfile, make_pp_args,
+                        config.compile_lib_path, option::some(src))
     }
 
     fn make_pp_args(config: config, _testfile: str) -> procargs {
@@ -173,9 +172,9 @@ actual:\n\
         }
     }
 
-    fn typecheck_source(cx: cx, testfile: str, src: str) -> procres {
-        compose_and_run(cx, testfile, make_typecheck_args,
-                        cx.config.compile_lib_path, option::some(src))
+    fn typecheck_source(config: config, testfile: str, src: str) -> procres {
+        compose_and_run(config, testfile, make_typecheck_args,
+                        config.compile_lib_path, option::some(src))
     }
 
     fn make_typecheck_args(config: config, _testfile: str) -> procargs {
@@ -286,22 +285,24 @@ type procargs = {prog: str, args: [str]};
 
 type procres = {status: int, stdout: str, stderr: str, cmdline: str};
 
-fn compile_test(cx: cx, props: test_props, testfile: str) -> procres {
-    compose_and_run(cx, testfile, bind make_compile_args(_, props, _),
-                    cx.config.compile_lib_path, option::none)
+fn compile_test(config: config, props: test_props,
+                testfile: str) -> procres {
+    compose_and_run(config, testfile, bind make_compile_args(_, props, _),
+                    config.compile_lib_path, option::none)
 }
 
-fn exec_compiled_test(cx: cx, props: test_props, testfile: str) -> procres {
-    compose_and_run(cx, testfile, bind make_run_args(_, props, _),
-                    cx.config.run_lib_path, option::none)
+fn exec_compiled_test(config: config, props: test_props,
+                      testfile: str) -> procres {
+    compose_and_run(config, testfile, bind make_run_args(_, props, _),
+                    config.run_lib_path, option::none)
 }
 
-fn compose_and_run(cx: cx, testfile: str,
+fn compose_and_run(config: config, testfile: str,
                    make_args: fn@(config, str) -> procargs, lib_path: str,
                    input: option<str>) -> procres {
-    let procargs = make_args(cx.config, testfile);
-    ret program_output(cx, testfile, lib_path, procargs.prog, procargs.args,
-                       input);
+    let procargs = make_args(config, testfile);
+    ret program_output(config, testfile, lib_path,
+                       procargs.prog, procargs.args, input);
 }
 
 fn make_compile_args(config: config, props: test_props, testfile: str) ->
@@ -354,16 +355,16 @@ fn split_maybe_args(argstr: option<str>) -> [str] {
     }
 }
 
-fn program_output(cx: cx, testfile: str, lib_path: str, prog: str,
+fn program_output(config: config, testfile: str, lib_path: str, prog: str,
                   args: [str], input: option<str>) -> procres {
     let cmdline =
         {
             let cmdline = make_cmdline(lib_path, prog, args);
-            logv(cx.config, #fmt["executing %s", cmdline]);
+            logv(config, #fmt["executing %s", cmdline]);
             cmdline
         };
-    let res = procsrv::run(cx.procsrv, lib_path, prog, args, input);
-    dump_output(cx.config, testfile, res.out, res.err);
+    let res = procsrv::run(lib_path, prog, args, input);
+    dump_output(config, testfile, res.out, res.err);
     ret {status: res.status,
          stdout: res.out,
          stderr: res.err,
diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index 0c03aca1245..7af87f77ecf 100644
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -1298,15 +1298,6 @@ const tag_five_b: uint = 248u;
 const max_five_b: uint = 67108864u;
 const tag_six_b: uint = 252u;
 
-// NB: This is intentionally unexported because it's easy to misuse (there's
-// no guarantee that the string is rooted). Instead, use as_buf below.
-unsafe fn buf(s: str) -> sbuf {
-    let saddr = ptr::addr_of(s);
-    let vaddr: *[u8] = ::unsafe::reinterpret_cast(saddr);
-    let buf = vec::to_ptr(*vaddr);
-    ret buf;
-}
-
 /*
 Function: as_buf
 
@@ -1319,7 +1310,10 @@ Example:
 
 */
 fn as_buf<T>(s: str, f: fn(sbuf) -> T) -> T unsafe {
-    let buf = buf(s); f(buf)
+    let v: [u8] = ::unsafe::reinterpret_cast(s);
+    let r = vec::as_buf(v, f);
+    ::unsafe::leak(v);
+    r
 }
 
 /*
diff --git a/src/libcore/vec.rs b/src/libcore/vec.rs
index 0dc5dea59bc..28c93718e5b 100644
--- a/src/libcore/vec.rs
+++ b/src/libcore/vec.rs
@@ -1077,6 +1077,18 @@ FIXME: We don't need this wrapper
 */
 unsafe fn to_ptr<T>(v: [T]) -> *T { ret unsafe::to_ptr(v); }
 
+/*
+Function: as_buf
+
+Work with the buffer of a vector. Allows for unsafe manipulation
+of vector contents, which is useful for native interop.
+
+*/
+fn as_buf<E,T>(v: [const E], f: fn(*E) -> T) -> T unsafe {
+    let buf = unsafe::to_ptr(v); f(buf)
+}
+
+
 /*
 Module: unsafe
 */
diff --git a/src/libstd/freebsd_os.rs b/src/libstd/freebsd_os.rs
index 315813c0848..d7ca27b550b 100644
--- a/src/libstd/freebsd_os.rs
+++ b/src/libstd/freebsd_os.rs
@@ -20,6 +20,7 @@ export target_os;
 export dylib_filename;
 export get_exe_path;
 export fsync_fd;
+export rustrt;
 
 // FIXME Somehow merge stuff duplicated here and macosx_os.rs. Made difficult
 // by https://github.com/graydon/rust/issues#issue/268
@@ -116,6 +117,7 @@ fn waitpid(pid: pid_t) -> i32 {
 
 #[abi = "cdecl"]
 native mod rustrt {
+    fn rust_env_pairs() -> [str];
     fn rust_getcwd() -> str;
 }
 
diff --git a/src/libstd/generic_os.rs b/src/libstd/generic_os.rs
index f41e83fa5fb..0f9f8a58410 100644
--- a/src/libstd/generic_os.rs
+++ b/src/libstd/generic_os.rs
@@ -11,21 +11,23 @@ import core::option;
 // Wow, this is an ugly way to write doc comments
 
 #[cfg(bogus)]
-/*
-Function: getenv
-
-Get the value of an environment variable
-*/
+#[doc = "Get the value of an environment variable"]
 fn getenv(n: str) -> option<str> { }
 
 #[cfg(bogus)]
-/*
-Function: setenv
-
-Set the value of an environment variable
-*/
+#[doc = "Set the value of an environment variable"]
 fn setenv(n: str, v: str) { }
 
+fn env() -> [(str,str)] {
+    let pairs = [];
+    for p in os::rustrt::rust_env_pairs() {
+        let vs = str::split(p, '=' as u8);
+        assert vec::len(vs) == 2u;
+        pairs += [(vs[0], vs[1])];
+    }
+    ret pairs;
+}
+
 #[cfg(target_os = "linux")]
 #[cfg(target_os = "macos")]
 #[cfg(target_os = "freebsd")]
diff --git a/src/libstd/linux_os.rs b/src/libstd/linux_os.rs
index 05722333df8..0231add3cd4 100644
--- a/src/libstd/linux_os.rs
+++ b/src/libstd/linux_os.rs
@@ -20,6 +20,7 @@ export target_os;
 export dylib_filename;
 export get_exe_path;
 export fsync_fd;
+export rustrt;
 
 // FIXME Somehow merge stuff duplicated here and macosx_os.rs. Made difficult
 // by https://github.com/graydon/rust/issues#issue/268
@@ -112,6 +113,7 @@ fn waitpid(pid: pid_t) -> i32 {
 
 #[abi = "cdecl"]
 native mod rustrt {
+    fn rust_env_pairs() -> [str];
     fn rust_getcwd() -> str;
 }
 
diff --git a/src/libstd/macos_os.rs b/src/libstd/macos_os.rs
index 920061cfd31..e44bc4c20e2 100644
--- a/src/libstd/macos_os.rs
+++ b/src/libstd/macos_os.rs
@@ -14,6 +14,7 @@ export target_os;
 export dylib_filename;
 export get_exe_path;
 export fsync_fd;
+export rustrt;
 
 // FIXME Refactor into unix_os module or some such. Doesn't
 // seem to work right now.
@@ -115,6 +116,7 @@ fn fsync_fd(fd: fd_t, level: io::fsync::level) -> c_int {
 
 #[abi = "cdecl"]
 native mod rustrt {
+    fn rust_env_pairs() -> [str];
     fn rust_getcwd() -> str;
 }
 
diff --git a/src/libstd/run_program.rs b/src/libstd/run_program.rs
index f81eda3aeeb..fa827c96f2f 100644
--- a/src/libstd/run_program.rs
+++ b/src/libstd/run_program.rs
@@ -5,7 +5,7 @@ Process spawning
 */
 import option::{some, none};
 import str::sbuf;
-import ctypes::{fd_t, pid_t};
+import ctypes::{fd_t, pid_t, void};
 
 export program;
 export run_program;
@@ -16,8 +16,9 @@ export waitpid;
 
 #[abi = "cdecl"]
 native mod rustrt {
-    fn rust_run_program(argv: *sbuf, in_fd: fd_t,
-                        out_fd: fd_t, err_fd: fd_t) -> pid_t;
+    fn rust_run_program(argv: *sbuf, envp: *void, dir: sbuf,
+                        in_fd: fd_t, out_fd: fd_t, err_fd: fd_t)
+        -> pid_t;
 }
 
 /* Section: Types */
@@ -82,13 +83,6 @@ iface program {
 
 /* Section: Operations */
 
-fn arg_vec(prog: str, args: [@str]) -> [sbuf] {
-    let argptrs = str::as_buf(prog, {|buf| [buf] });
-    for arg in args { argptrs += str::as_buf(*arg, {|buf| [buf] }); }
-    argptrs += [ptr::null()];
-    ret argptrs;
-}
-
 /*
 Function: spawn_process
 
@@ -98,6 +92,8 @@ Parameters:
 
 prog - The path to an executable
 args - Vector of arguments to pass to the child process
+env - optional env-modification for child
+dir - optional dir to run child in (default current dir)
 in_fd - A file descriptor for the child to use as std input
 out_fd - A file descriptor for the child to use as std output
 err_fd - A file descriptor for the child to use as std error
@@ -106,18 +102,90 @@ Returns:
 
 The process id of the spawned process
 */
-fn spawn_process(prog: str, args: [str], in_fd: fd_t,
-                 out_fd: fd_t, err_fd: fd_t)
+fn spawn_process(prog: str, args: [str],
+                 env: option<[(str,str)]>,
+                 dir: option<str>,
+                 in_fd: fd_t, out_fd: fd_t, err_fd: fd_t)
    -> pid_t unsafe {
-    // Note: we have to hold on to these vector references while we hold a
-    // pointer to their buffers
-    let prog = prog;
-    let args = vec::map(args, {|arg| @arg });
-    let argv = arg_vec(prog, args);
-    let pid =
-        rustrt::rust_run_program(vec::unsafe::to_ptr(argv), in_fd, out_fd,
-                                 err_fd);
-    ret pid;
+    with_argv(prog, args) {|argv|
+        with_envp(env) { |envp|
+            with_dirp(dir) { |dirp|
+                rustrt::rust_run_program(argv, envp, dirp,
+                                         in_fd, out_fd, err_fd)
+            }
+        }
+    }
+}
+
+fn with_argv<T>(prog: str, args: [str],
+                cb: fn(*sbuf) -> T) -> T unsafe {
+    let argptrs = str::as_buf(prog) {|b| [b] };
+    let tmps = [];
+    for arg in args {
+        let t = @arg;
+        tmps += [t];
+        argptrs += str::as_buf(*t) {|b| [b] };
+    }
+    argptrs += [ptr::null()];
+    vec::as_buf(argptrs, cb)
+}
+
+#[cfg(target_os = "macos")]
+#[cfg(target_os = "linux")]
+#[cfg(target_os = "freebsd")]
+fn with_envp<T>(env: option<[(str,str)]>,
+                cb: fn(*void) -> T) -> T unsafe {
+    // On posixy systems we can pass a char** for envp, which is
+    // a null-terminated array of "k=v\n" strings.
+    alt env {
+      some (es) {
+        let tmps = [];
+        let ptrs = [];
+
+        for (k,v) in es {
+            let t = @(#fmt("%s=%s", k, v));
+            vec::push(tmps, t);
+            ptrs += str::as_buf(*t) {|b| [b]};
+        }
+        ptrs += [ptr::null()];
+        vec::as_buf(ptrs) { |p| cb(::unsafe::reinterpret_cast(p)) }
+      }
+      none {
+        cb(ptr::null())
+      }
+    }
+}
+
+#[cfg(target_os = "win32")]
+fn with_envp<T>(env: option<[(str,str)]>,
+                cb: fn(*void) -> T) -> T unsafe {
+    // On win32 we pass an "environment block" which is not a char**, but
+    // rather a concatenation of null-terminated k=v\0 sequences, with a final
+    // \0 to terminate.
+    alt env {
+      some (es) {
+        let blk : [u8] = [];
+        for (k,v) in es {
+            let t = #fmt("%s=%s", k, v);
+            let v : [u8] = ::unsafe::reinterpret_cast(t);
+            blk += v;
+            ::unsafe::leak(v);
+        }
+        blk += [0_u8];
+        vec::as_buf(blk) {|p| cb(::unsafe::reinterpret_cast(p)) }
+      }
+      none {
+        cb(ptr::null())
+      }
+    }
+}
+
+fn with_dirp<T>(d: option<str>,
+                cb: fn(sbuf) -> T) -> T unsafe {
+    alt d {
+      some(dir) { str::as_buf(dir, cb) }
+      none { cb(ptr::null()) }
+    }
 }
 
 /*
@@ -135,7 +203,8 @@ Returns:
 The process id
 */
 fn run_program(prog: str, args: [str]) -> int {
-    ret waitpid(spawn_process(prog, args, 0i32, 0i32, 0i32));
+    ret waitpid(spawn_process(prog, args, none, none,
+                              0i32, 0i32, 0i32));
 }
 
 /*
@@ -161,7 +230,8 @@ fn start_program(prog: str, args: [str]) -> program {
     let pipe_output = os::pipe();
     let pipe_err = os::pipe();
     let pid =
-        spawn_process(prog, args, pipe_input.in, pipe_output.out,
+        spawn_process(prog, args, none, none,
+                      pipe_input.in, pipe_output.out,
                       pipe_err.out);
 
     if pid == -1i32 { fail; }
@@ -316,7 +386,8 @@ mod tests {
 
         let pid =
             run::spawn_process(
-                "cat", [], pipe_in.in, pipe_out.out, pipe_err.out);
+                "cat", [], none, none,
+                pipe_in.in, pipe_out.out, pipe_err.out);
         os::close(pipe_in.in);
         os::close(pipe_out.out);
         os::close(pipe_err.out);
@@ -356,7 +427,9 @@ mod tests {
 
     #[test]
     fn waitpid() {
-        let pid = run::spawn_process("false", [], 0i32, 0i32, 0i32);
+        let pid = run::spawn_process("false", [],
+                                     none, none,
+                                     0i32, 0i32, 0i32);
         let status = run::waitpid(pid);
         assert status == 1;
     }
diff --git a/src/libstd/test.rs b/src/libstd/test.rs
index 6d7273ff0b1..8d5ecda2c48 100644
--- a/src/libstd/test.rs
+++ b/src/libstd/test.rs
@@ -227,10 +227,19 @@ fn run_tests(opts: test_opts, tests: [test_desc],
     }
 }
 
+// Windows tends to dislike being overloaded with threads.
+#[cfg(target_os = "win32")]
+const sched_overcommit : uint = 1u;
+
+#[cfg(target_os = "linux")]
+#[cfg(target_os = "freebsd")]
+#[cfg(target_os = "macos")]
+const sched_overcommit : uint = 4u;
+
 fn get_concurrency() -> uint {
     let threads = rustrt::sched_threads();
     if threads == 1u { 1u }
-    else { threads * 4u }
+    else { threads * sched_overcommit }
 }
 
 fn filter_tests(opts: test_opts,
diff --git a/src/libstd/win32_os.rs b/src/libstd/win32_os.rs
index ddc1ebd7a35..aa589cf3c32 100644
--- a/src/libstd/win32_os.rs
+++ b/src/libstd/win32_os.rs
@@ -106,6 +106,7 @@ fn fsync_fd(_fd: fd_t, _level: io::fsync::level) -> c_int {
 
 #[abi = "cdecl"]
 native mod rustrt {
+    fn rust_env_pairs() -> [str];
     fn rust_process_wait(handle: c_int) -> c_int;
     fn rust_getcwd() -> str;
 }
diff --git a/src/rt/rust.cpp b/src/rt/rust.cpp
index b5af3942a20..dacbcee1045 100644
--- a/src/rt/rust.cpp
+++ b/src/rt/rust.cpp
@@ -41,16 +41,7 @@ command_line_args : public kernel_owned<command_line_args>
         LocalFree(wargv);
 #endif
 
-        args = (rust_vec *)
-            kernel->malloc(vec_size<rust_vec*>(argc),
-                           "command line arg interior");
-        args->fill = args->alloc = sizeof(rust_vec*) * argc;
-        for (int i = 0; i < argc; ++i) {
-            rust_str *str = make_str(kernel, argv[i],
-                                     strlen(argv[i]),
-                                     "command line arg");
-            ((rust_str**)&args->data)[i] = str;
-        }
+        args = make_str_vec(kernel, argc, argv);
     }
 
     ~command_line_args() {
diff --git a/src/rt/rust_builtin.cpp b/src/rt/rust_builtin.cpp
index 8fbe0ed7888..76f80192e89 100644
--- a/src/rt/rust_builtin.cpp
+++ b/src/rt/rust_builtin.cpp
@@ -7,6 +7,10 @@
 #include "rust_scheduler.h"
 #include "sync/timer.h"
 
+#ifdef __APPLE__
+#include <crt_externs.h>
+#endif
+
 #if !defined(__WIN32__)
 #include <sys/time.h>
 #endif
@@ -73,6 +77,49 @@ rust_getcwd() {
     return make_str(task->kernel, cbuf, strlen(cbuf), "rust_str(getcwd");
 }
 
+
+#if defined(__WIN32__)
+extern "C" CDECL rust_vec *
+rust_env_pairs() {
+    rust_task *task = rust_task_thread::get_task();
+    size_t envc = 0;
+    LPTCH ch = GetEnvironmentStringsA();
+    LPTCH c;
+    for (c = ch; *c; c += strlen(c) + 1) {
+        ++envc;
+    }
+    c = ch;
+    rust_vec *v = (rust_vec *)
+        task->kernel->malloc(vec_size<rust_vec*>(envc),
+                       "str vec interior");
+    v->fill = v->alloc = sizeof(rust_vec*) * envc;
+    for (size_t i = 0; i < envc; ++i) {
+        size_t n = strlen(c);
+        rust_str *str = make_str(task->kernel, c, n, "str");
+        ((rust_str**)&v->data)[i] = str;
+        c += n + 1;
+    }
+    if (ch) {
+        FreeEnvironmentStrings(ch);
+    }
+    return v;
+}
+#else
+extern "C" CDECL rust_vec *
+rust_env_pairs() {
+    rust_task *task = rust_task_thread::get_task();
+#ifdef __APPLE__
+    char **environ = *_NSGetEnviron();
+#endif
+    char **e = environ;
+    size_t envc = 0;
+    while (*e) {
+        ++envc; ++e;
+    }
+    return make_str_vec(task->kernel, envc, environ);
+}
+#endif
+
 // TODO: Allow calling native functions that return double results.
 extern "C" CDECL
 void squareroot(double *input, double *output) {
diff --git a/src/rt/rust_run_program.cpp b/src/rt/rust_run_program.cpp
index df4714758dd..848b015dd6c 100644
--- a/src/rt/rust_run_program.cpp
+++ b/src/rt/rust_run_program.cpp
@@ -1,5 +1,9 @@
 #include "rust_internal.h"
 
+#ifdef __APPLE__
+#include <crt_externs.h>
+#endif
+
 #if defined(__WIN32__)
 
 #include <process.h>
@@ -64,7 +68,10 @@ void append_arg(char *& buf, char const *arg, bool last) {
 }
 
 extern "C" CDECL int
-rust_run_program(const char* argv[], int in_fd, int out_fd, int err_fd) {
+rust_run_program(const char* argv[],
+                 void* envp,
+                 const char* dir,
+                 int in_fd, int out_fd, int err_fd) {
     STARTUPINFO si;
     ZeroMemory(&si, sizeof(STARTUPINFO));
     si.cb = sizeof(STARTUPINFO);
@@ -99,7 +106,7 @@ rust_run_program(const char* argv[], int in_fd, int out_fd, int err_fd) {
 
     PROCESS_INFORMATION pi;
     BOOL created = CreateProcess(NULL, cmd, NULL, NULL, TRUE,
-                                 0, NULL, NULL, &si, &pi);
+                                 0, envp, dir, &si, &pi);
 
     CloseHandle(si.hStdInput);
     CloseHandle(si.hStdOutput);
@@ -130,7 +137,10 @@ rust_process_wait(int proc) {
 #include <termios.h>
 
 extern "C" CDECL int
-rust_run_program(char* argv[], int in_fd, int out_fd, int err_fd) {
+rust_run_program(const char* argv[],
+                 void* envp,
+                 const char* dir,
+                 int in_fd, int out_fd, int err_fd) {
     int pid = fork();
     if (pid != 0) return pid;
 
@@ -143,7 +153,18 @@ rust_run_program(char* argv[], int in_fd, int out_fd, int err_fd) {
     if (err_fd) dup2(err_fd, 2);
     /* Close all other fds. */
     for (int fd = getdtablesize() - 1; fd >= 3; fd--) close(fd);
-    execvp(argv[0], argv);
+    if (dir) { chdir(dir); }
+
+#ifdef __APPLE__
+    if (envp) {
+        *_NSGetEnviron() = (char **)envp;
+    }
+    execvp(argv[0], (char * const *)argv);
+#else
+    if (!envp) { envp = environ; }
+    execvpe(argv[0], (char * const *)argv, (char * const *)envp);
+#endif
+
     exit(1);
 }
 
diff --git a/src/rt/rust_util.h b/src/rt/rust_util.h
index 07569db3ffa..1b611dd0be6 100644
--- a/src/rt/rust_util.h
+++ b/src/rt/rust_util.h
@@ -204,6 +204,21 @@ make_str(rust_kernel* kernel, const char* c, size_t strlen, const char* name) {
     return str;
 }
 
+inline rust_vec *
+make_str_vec(rust_kernel* kernel, size_t nstrs, char **strs) {
+    rust_vec *v = (rust_vec *)
+        kernel->malloc(vec_size<rust_vec*>(nstrs),
+                       "str vec interior");
+    v->fill = v->alloc = sizeof(rust_vec*) * nstrs;
+    for (size_t i = 0; i < nstrs; ++i) {
+        rust_str *str = make_str(kernel, strs[i],
+                                 strlen(strs[i]),
+                                 "str");
+        ((rust_str**)&v->data)[i] = str;
+    }
+    return v;
+}
+
 //
 // Local Variables:
 // mode: C++
diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in
index 48736ef029b..81f8a9c25f7 100644
--- a/src/rt/rustrt.def.in
+++ b/src/rt/rustrt.def.in
@@ -42,6 +42,7 @@ rust_run_program
 rust_set_exit_status
 rust_start
 rust_getcwd
+rust_env_pairs
 rust_task_yield
 rust_task_is_unwinding
 rust_get_task