io: Implement process wait timeouts

This implements set_timeout() for std::io::Process which will affect wait()
operations on the process. This follows the same pattern as the rest of the
timeouts emerging in std::io::net.

The implementation was super easy for everything except libnative on unix
(backwards from usual!), which required a good bit of signal handling. There's a
doc comment explaining the strategy in libnative. Internally, this also required
refactoring the "helper thread" implementation used by libnative to allow for an
extra helper thread (not just the timer).

This is a breaking change in terms of the io::Process API. It is now possible
for wait() to fail, and subsequently wait_with_output(). These two functions now
return IoResult<T> due to the fact that they can time out.

Additionally, the wait_with_output() function has moved from taking `&mut self`
to taking `self`. If a timeout occurs while waiting with output, the semantics
are undesirable in almost all cases if attempting to re-wait on the process.
Equivalent functionality can still be achieved by dealing with the output
handles manually.

[breaking-change]

cc #13523

Author: alexcrichton

src/compiletest/procsrv.rs

@@ -68,19 +68,20 @@ pub fn run(lib_path: &str,
            input: Option<~str>) -> Option<Result> {
 
     let env = env.clone().append(target_env(lib_path, prog).as_slice());
-    let mut opt_process = Process::configure(ProcessConfig {
+    let opt_process = Process::configure(ProcessConfig {
         program: prog,
         args: args,
         env: Some(env.as_slice()),
         .. ProcessConfig::new()
     });
 
     match opt_process {
-        Ok(ref mut process) => {
+        Ok(mut process) => {
             for input in input.iter() {
                 process.stdin.get_mut_ref().write(input.as_bytes()).unwrap();
             }
-            let ProcessOutput { status, output, error } = process.wait_with_output();
+            let ProcessOutput { status, output, error } =
+                process.wait_with_output().unwrap();
 
             Some(Result {
                 status: status,

src/compiletest/runtest.rs

@@ -502,16 +502,17 @@ fn run_debuginfo_lldb_test(config: &Config, props: &TestProps, testfile: &Path)
         let args = &[lldb_batchmode_script, test_executable_str, debugger_script_str];
         let env = &[("PYTHONPATH".to_owned(), config.lldb_python_dir.clone().unwrap())];
 
-        let mut opt_process = Process::configure(ProcessConfig {
+        let opt_process = Process::configure(ProcessConfig {
             program: "python",
             args: args,
             env: Some(env),
             .. ProcessConfig::new()
         });
 
         let (status, out, err) = match opt_process {
-            Ok(ref mut process) => {
-                let ProcessOutput { status, output, error } = process.wait_with_output();
+            Ok(process) => {
+                let ProcessOutput { status, output, error } =
+                    process.wait_with_output().unwrap();
 
                 (status,
                  str::from_utf8(output.as_slice()).unwrap().to_owned(),

src/libcore/str.rs

@@ -1725,6 +1725,7 @@ impl<'a> StrSlice<'a> for &'a str {
     #[inline]
     fn is_char_boundary(&self, index: uint) -> bool {
         if index == self.len() { return true; }
+        if index > self.len() { return false; }
         let b = self[index];
         return b < 128u8 || b >= 192u8;
     }

src/liblibc/lib.rs

@@ -173,7 +173,7 @@ pub use funcs::bsd43::{shutdown};
 #[cfg(unix)] pub use consts::os::posix88::{EADDRINUSE, ENOENT, EISDIR, EAGAIN, EWOULDBLOCK};
 #[cfg(unix)] pub use consts::os::posix88::{ECANCELED, SIGINT, EINPROGRESS};
 #[cfg(unix)] pub use consts::os::posix88::{SIGTERM, SIGKILL, SIGPIPE, PROT_NONE};
-#[cfg(unix)] pub use consts::os::posix01::{SIG_IGN, WNOHANG};
+#[cfg(unix)] pub use consts::os::posix01::{SIG_IGN};
 #[cfg(unix)] pub use consts::os::bsd44::{AF_UNIX};
 
 #[cfg(unix)] pub use types::os::common::posix01::{pthread_t, timespec, timezone};
@@ -2473,8 +2473,6 @@ pub mod consts {
 
             pub static CLOCK_REALTIME: c_int = 0;
             pub static CLOCK_MONOTONIC: c_int = 1;
-
-            pub static WNOHANG: c_int = 1;
         }
         pub mod posix08 {
         }
@@ -2924,8 +2922,6 @@ pub mod consts {
 
             pub static CLOCK_REALTIME: c_int = 0;
             pub static CLOCK_MONOTONIC: c_int = 4;
-
-            pub static WNOHANG: c_int = 1;
         }
         pub mod posix08 {
         }
@@ -3313,8 +3309,6 @@ pub mod consts {
             pub static PTHREAD_CREATE_JOINABLE: c_int = 1;
             pub static PTHREAD_CREATE_DETACHED: c_int = 2;
             pub static PTHREAD_STACK_MIN: size_t = 8192;
-
-            pub static WNOHANG: c_int = 1;
         }
         pub mod posix08 {
         }
@@ -3980,16 +3974,6 @@ pub mod funcs {
             }
         }
 
-        pub mod wait {
-            use types::os::arch::c95::{c_int};
-            use types::os::arch::posix88::{pid_t};
-
-            extern {
-                pub fn waitpid(pid: pid_t, status: *mut c_int, options: c_int)
-                               -> pid_t;
-            }
-        }
-
         pub mod glob {
             use types::os::arch::c95::{c_char, c_int};
             use types::os::common::posix01::{glob_t};

src/libnative/io/c_unix.rs

@@ -10,7 +10,12 @@
 
 //! C definitions used by libnative that don't belong in liblibc
 
+#![allow(dead_code)]
+
 pub use self::select::fd_set;
+pub use self::signal::{sigaction, siginfo, sigset_t};
+pub use self::signal::{SA_ONSTACK, SA_RESTART, SA_RESETHAND, SA_NOCLDSTOP};
+pub use self::signal::{SA_NODEFER, SA_NOCLDWAIT, SA_SIGINFO, SIGCHLD};
 
 use libc;
 
@@ -34,6 +39,8 @@ pub static MSG_DONTWAIT: libc::c_int = 0x80;
 #[cfg(target_os = "android")]
 pub static MSG_DONTWAIT: libc::c_int = 0x40;
 
+pub static WNOHANG: libc::c_int = 1;
+
 extern {
     pub fn gettimeofday(timeval: *mut libc::timeval,
                         tzp: *libc::c_void) -> libc::c_int;
@@ -49,6 +56,17 @@ extern {
                       optlen: *mut libc::socklen_t) -> libc::c_int;
     pub fn ioctl(fd: libc::c_int, req: libc::c_ulong, ...) -> libc::c_int;
 
+
+    pub fn waitpid(pid: libc::pid_t, status: *mut libc::c_int,
+                   options: libc::c_int) -> libc::pid_t;
+
+    pub fn sigaction(signum: libc::c_int,
+                     act: *sigaction,
+                     oldact: *mut sigaction) -> libc::c_int;
+
+    pub fn sigaddset(set: *mut sigset_t, signum: libc::c_int) -> libc::c_int;
+    pub fn sigdelset(set: *mut sigset_t, signum: libc::c_int) -> libc::c_int;
+    pub fn sigemptyset(set: *mut sigset_t) -> libc::c_int;
 }
 
 #[cfg(target_os = "macos")]
@@ -81,3 +99,94 @@ mod select {
         set.fds_bits[fd / uint::BITS] |= 1 << (fd % uint::BITS);
     }
 }
+
+#[cfg(target_os = "linux")]
+#[cfg(target_os = "android")]
+mod signal {
+    use libc;
+
+    pub static SA_NOCLDSTOP: libc::c_ulong = 0x00000001;
+    pub static SA_NOCLDWAIT: libc::c_ulong = 0x00000002;
+    pub static SA_NODEFER: libc::c_ulong = 0x40000000;
+    pub static SA_ONSTACK: libc::c_ulong = 0x08000000;
+    pub static SA_RESETHAND: libc::c_ulong = 0x80000000;
+    pub static SA_RESTART: libc::c_ulong = 0x10000000;
+    pub static SA_SIGINFO: libc::c_ulong = 0x00000004;
+    pub static SIGCHLD: libc::c_int = 17;
+
+    // This definition is not as accurate as it could be, {pid, uid, status} is
+    // actually a giant union. Currently we're only interested in these fields,
+    // however.
+    pub struct siginfo {
+        si_signo: libc::c_int,
+        si_errno: libc::c_int,
+        si_code: libc::c_int,
+        pub pid: libc::pid_t,
+        pub uid: libc::uid_t,
+        pub status: libc::c_int,
+    }
+
+    pub struct sigaction {
+        pub sa_handler: extern fn(libc::c_int),
+        pub sa_mask: sigset_t,
+        pub sa_flags: libc::c_ulong,
+        sa_restorer: *mut libc::c_void,
+    }
+
+    #[cfg(target_word_size = "32")]
+    pub struct sigset_t {
+        __val: [libc::c_ulong, ..32],
+    }
+    #[cfg(target_word_size = "64")]
+    pub struct sigset_t {
+        __val: [libc::c_ulong, ..16],
+    }
+}
+
+#[cfg(target_os = "macos")]
+#[cfg(target_os = "freebsd")]
+mod signal {
+    use libc;
+
+    pub static SA_ONSTACK: libc::c_int = 0x0001;
+    pub static SA_RESTART: libc::c_int = 0x0002;
+    pub static SA_RESETHAND: libc::c_int = 0x0004;
+    pub static SA_NOCLDSTOP: libc::c_int = 0x0008;
+    pub static SA_NODEFER: libc::c_int = 0x0010;
+    pub static SA_NOCLDWAIT: libc::c_int = 0x0020;
+    pub static SA_SIGINFO: libc::c_int = 0x0040;
+    pub static SIGCHLD: libc::c_int = 20;
+
+    #[cfg(target_os = "macos")]
+    pub type sigset_t = u32;
+    #[cfg(target_os = "freebsd")]
+    pub struct sigset_t {
+        bits: [u32, ..4],
+    }
+
+    // This structure has more fields, but we're not all that interested in
+    // them.
+    pub struct siginfo {
+        pub si_signo: libc::c_int,
+        pub si_errno: libc::c_int,
+        pub si_code: libc::c_int,
+        pub pid: libc::pid_t,
+        pub uid: libc::uid_t,
+        pub status: libc::c_int,
+    }
+
+    #[cfg(target_os = "macos")]
+    pub struct sigaction {
+        pub sa_handler: extern fn(libc::c_int),
+        sa_tramp: *mut libc::c_void,
+        pub sa_mask: sigset_t,
+        pub sa_flags: libc::c_int,
+    }
+
+    #[cfg(target_os = "freebsd")]
+    pub struct sigaction {
+        pub sa_handler: extern fn(libc::c_int),
+        pub sa_flags: libc::c_int,
+        pub sa_mask: sigset_t,
+    }
+}