core: Serialize all access to the environment using a weak global task

Author: brson

src/libcore/core.rc

@@ -199,6 +199,7 @@ mod extfmt;
 mod unicode;
 mod priv;
 mod cmath;
+mod global_env;
 
 
 // Local Variables:

src/libcore/global_env.rs

@@ -0,0 +1,124 @@
+#[doc = "Internal module for serializing access to getenv/setenv"];
+
+export getenv;
+export setenv;
+
+native mod rustrt {
+    fn rust_global_env_chan_ptr() -> *libc::uintptr_t;
+}
+
+enum msg {
+    msg_getenv(str, comm::chan<option<str>>),
+    msg_setenv(str, str, comm::chan<()>)
+}
+
+fn getenv(n: str) -> option<str> {
+    let env_ch = get_global_env_chan();
+    let po = comm::port();
+    comm::send(env_ch, msg_getenv(n, comm::chan(po)));
+    comm::recv(po)
+}
+
+fn setenv(n: str, v: str) {
+    let env_ch = get_global_env_chan();
+    let po = comm::port();
+    comm::send(env_ch, msg_setenv(n, v, comm::chan(po)));
+    comm::recv(po)
+}
+
+fn get_global_env_chan() -> comm::chan<msg> {
+    let global_ptr = rustrt::rust_global_env_chan_ptr();
+    let builder_fn = {||
+        let builder = task::builder();
+        task::unsupervise(builder);
+        task::set_opts(builder, {
+            sched:  some({
+                mode: task::single_threaded,
+                // FIXME: This would be a good place to use
+                // a very small native stack
+                native_stack_size: none
+            })
+            with task::get_opts(builder)
+        });
+        builder
+    };
+    unsafe {
+        priv::chan_from_global_ptr(
+            global_ptr, builder_fn, global_env_task)
+    }
+}
+
+fn global_env_task(msg_po: comm::port<msg>) unsafe {
+    priv::weaken_task {|weak_po|
+        loop {
+            alt comm::select2(msg_po, weak_po) {
+              either::left(msg_getenv(n, resp_ch)) {
+                comm::send(resp_ch, impl::getenv(n))
+              }
+              either::left(msg_setenv(n, v, resp_ch)) {
+                comm::send(resp_ch, impl::setenv(n, v))
+              }
+              either::right(_) {
+                break;
+              }
+            }
+        }
+    }
+}
+
+mod impl {
+
+    #[cfg(target_os = "linux")]
+    #[cfg(target_os = "macos")]
+    #[cfg(target_os = "freebsd")]
+    fn getenv(n: str) -> option<str> unsafe {
+        let s = str::as_c_str(n, libc::getenv);
+        ret if unsafe::reinterpret_cast(s) == 0 {
+            option::none::<str>
+        } else {
+            let s = unsafe::reinterpret_cast(s);
+            option::some::<str>(str::unsafe::from_buf(s))
+        };
+    }
+
+    #[cfg(target_os = "win32")]
+    fn getenv(n: str) -> option<str> unsafe {
+        import libc::types::os::arch::extra::*;
+        import libc::funcs::extra::kernel32::*;
+        import win32::*;
+        as_utf16_p(n) {|u|
+            fill_utf16_buf_and_decode() {|buf, sz|
+                GetEnvironmentVariableW(u, buf, sz)
+            }
+        }
+    }
+
+
+    #[cfg(target_os = "linux")]
+    #[cfg(target_os = "macos")]
+    #[cfg(target_os = "freebsd")]
+    fn setenv(n: str, v: str) {
+
+        // FIXME: remove this when export globs work properly.
+        import libc::funcs::posix01::unistd::setenv;
+        str::as_c_str(n) {|nbuf|
+            str::as_c_str(v) {|vbuf|
+                setenv(nbuf, vbuf, 1i32);
+            }
+        }
+    }
+
+
+    #[cfg(target_os = "win32")]
+    fn setenv(n: str, v: str) {
+        // FIXME: remove imports when export globs work properly.
+        import libc::funcs::extra::kernel32::*;
+        import win32::*;
+        as_utf16_p(n) {|nbuf|
+            as_utf16_p(v) {|vbuf|
+                SetEnvironmentVariableW(nbuf, vbuf);
+            }
+        }
+    }
+
+}

src/libcore/os.rs

@@ -121,61 +121,14 @@ mod win32 {
     }
 }
 
-
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "freebsd")]
-fn getenv(n: str) -> option<str> unsafe {
-    let s = as_c_charp(n, libc::getenv);
-    ret if unsafe::reinterpret_cast(s) == 0 {
-            option::none::<str>
-        } else {
-            let s = unsafe::reinterpret_cast(s);
-            option::some::<str>(str::unsafe::from_buf(s))
-        };
-}
-
-#[cfg(target_os = "win32")]
-fn getenv(n: str) -> option<str> unsafe {
-    import libc::types::os::arch::extra::*;
-    import libc::funcs::extra::kernel32::*;
-    import win32::*;
-    as_utf16_p(n) {|u|
-        fill_utf16_buf_and_decode() {|buf, sz|
-            GetEnvironmentVariableW(u, buf, sz)
-        }
-    }
-}
-
-
-#[cfg(target_os = "linux")]
-#[cfg(target_os = "macos")]
-#[cfg(target_os = "freebsd")]
-fn setenv(n: str, v: str) {
-
-    // FIXME: remove this when export globs work properly.
-    import libc::funcs::posix01::unistd::setenv;
-    as_c_charp(n) {|nbuf|
-        as_c_charp(v) {|vbuf|
-            setenv(nbuf, vbuf, 1i32);
-        }
-    }
+fn getenv(n: str) -> option<str> {
+    global_env::getenv(n)
 }
 
-
-#[cfg(target_os = "win32")]
 fn setenv(n: str, v: str) {
-    // FIXME: remove imports when export globs work properly.
-    import libc::funcs::extra::kernel32::*;
-    import win32::*;
-    as_utf16_p(n) {|nbuf|
-        as_utf16_p(v) {|vbuf|
-            SetEnvironmentVariableW(nbuf, vbuf);
-        }
-    }
+    global_env::setenv(n, v)
 }
 
-
 fn fdopen(fd: c_int) -> *FILE {
     ret as_c_charp("r") {|modebuf|
         libc::fdopen(fd, modebuf)
@@ -726,15 +679,13 @@ mod tests {
     }
 
     #[test]
-    #[ignore(reason = "fails periodically on mac")]
     fn test_setenv() {
         let n = make_rand_name();
         setenv(n, "VALUE");
         assert getenv(n) == option::some("VALUE");
     }
 
     #[test]
-    #[ignore(reason = "fails periodically on mac")]
     fn test_setenv_overwrite() {
         let n = make_rand_name();
         setenv(n, "1");
@@ -747,7 +698,6 @@ mod tests {
     // Windows GetEnvironmentVariable requires some extra work to make sure
     // the buffer the variable is copied into is the right size
     #[test]
-    #[ignore(reason = "fails periodically on mac")]
     fn test_getenv_big() {
         let mut s = "";
         let mut i = 0;

src/libstd/time.rs

@@ -823,21 +823,7 @@ impl tm for tm {
 mod tests {
     import task;
 
-    // FIXME #2160: These tests are all run in the same task because
-    // getenv/setenv interacts poorly with threads on OS X
     #[test]
-    fn test_all() {
-        test_get_time();
-        test_precise_time();
-        test_at_utc();
-        test_at();
-        test_to_timespec();
-        test_conversions();
-        test_strptime();
-        test_ctime();
-        test_strftime();
-    }
-
     fn test_get_time() {
         const some_recent_date: i64 = 1325376000i64; // 2012-01-01T00:00:00Z
         const some_future_date: i64 = 1577836800i64; // 2020-01-01T00:00:00Z
@@ -861,6 +847,7 @@ mod tests {
         }
     }
 
+    #[test]
     fn test_precise_time() {
         let s0 = precise_time_s();
         let ns1 = precise_time_ns();
@@ -878,6 +865,7 @@ mod tests {
         assert ns2 >= ns1;
     }
 
+    #[test]
     fn test_at_utc() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -898,6 +886,7 @@ mod tests {
         assert utc.tm_nsec == 54321_i32;
     }
 
+    #[test]
     fn test_at() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -923,6 +912,7 @@ mod tests {
         assert local.tm_nsec == 54321_i32;
     }
 
+    #[test]
     fn test_to_timespec() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -933,6 +923,7 @@ mod tests {
         assert utc.to_local().to_timespec() == time;
     }
 
+    #[test]
     fn test_conversions() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -948,6 +939,7 @@ mod tests {
         assert utc.to_local().to_utc() == utc;
     }
 
+    #[test]
     fn test_strptime() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -1092,6 +1084,7 @@ mod tests {
         assert test("%", "%%");
     }
 
+    #[test]
     fn test_ctime() {
         os::setenv("TZ", "America/Los_Angeles");
 
@@ -1103,6 +1096,7 @@ mod tests {
         assert local.ctime() == "Fri Feb 13 15:31:30 2009";
     }
 
+    #[test]
     fn test_strftime() {
         os::setenv("TZ", "America/Los_Angeles");
 

src/rt/rust_builtin.cpp

@@ -781,6 +781,12 @@ rust_task_unweaken(rust_port_id chan) {
     task->kernel->unweaken_task(chan);
 }
 
+extern "C" CDECL uintptr_t*
+rust_global_env_chan_ptr() {
+    rust_task *task = rust_get_current_task();
+    return task->kernel->get_global_env_chan();
+}
+
 //
 // Local Variables:
 // mode: C++

src/rt/rust_kernel.cpp

@@ -22,11 +22,11 @@ rust_kernel::rust_kernel(rust_env *env) :
     sched_reaper(this),
     osmain_driver(NULL),
     non_weak_tasks(0),
+    global_loop_chan(0),
+    global_env_chan(0),
     env(env)
+
 {
-    // set up storage of pointers needed to
-    // access the global loop.
-    global_loop_chan = 0;
 
     // Create the single threaded scheduler that will run on the platform's
     // main thread

src/rt/rust_kernel.h

@@ -75,6 +75,8 @@ class rust_kernel {
 
     // Used to communicate with the process-side, global libuv loop
     uintptr_t global_loop_chan;
+    // Used to serialize access to getenv/setenv
+    uintptr_t global_env_chan;
 
 public:
     struct rust_env *env;
@@ -122,6 +124,7 @@ class rust_kernel {
     bool send_to_port(rust_port_id chan, void *sptr);
 
     uintptr_t* get_global_loop() { return &global_loop_chan; }
+    uintptr_t* get_global_env_chan() { return &global_env_chan; }
 };
 
 template <typename T> struct kernel_owned {

src/rt/rustrt.def.in

@@ -147,4 +147,5 @@ rust_dbg_lock_wait
 rust_dbg_lock_signal
 rust_dbg_call
 rust_osmain_sched_id
-rust_compare_and_swap_ptr
+rust_compare_and_swap_ptr
+rust_global_env_chan_ptr