libs: merge librustrt into libstd

This commit merges the `rustrt` crate into `std`, undoing part of the
facade. This merger continues the paring down of the runtime system.

Code relying on the public API of `rustrt` will break; some of this API
is now available through `std::rt`, but is likely to change and/or be
removed very soon.

[breaking-change]

src/libstd/sys/unix/stack_overflow.rs

@@ -0,0 +1,291 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use libc;
+use core::prelude::*;
+use self::imp::{make_handler, drop_handler};
+
+pub use self::imp::{init, cleanup};
+
+pub struct Handler {
+    _data: *mut libc::c_void
+}
+
+impl Handler {
+    pub unsafe fn new() -> Handler {
+        make_handler()
+    }
+}
+
+impl Drop for Handler {
+    fn drop(&mut self) {
+        unsafe {
+            drop_handler(self);
+        }
+    }
+}
+
+#[cfg(any(target_os = "linux", target_os = "macos"))]
+mod imp {
+    use core::prelude::*;
+    use sys_common::stack;
+
+    use super::Handler;
+    use rt::util::report_overflow;
+    use mem;
+    use ptr;
+    use intrinsics;
+    use self::signal::{siginfo, sigaction, SIGBUS, SIG_DFL,
+                       SA_SIGINFO, SA_ONSTACK, sigaltstack,
+                       SIGSTKSZ};
+    use rt::local::Local;
+    use rt::task::Task;
+    use libc;
+    use libc::funcs::posix88::mman::{mmap, munmap};
+    use libc::consts::os::posix88::{SIGSEGV,
+                                    PROT_READ,
+                                    PROT_WRITE,
+                                    MAP_PRIVATE,
+                                    MAP_ANON,
+                                    MAP_FAILED};
+
+
+    // This is initialized in init() and only read from after
+    static mut PAGE_SIZE: uint = 0;
+
+    // get_task_info is called from an exception / signal handler.
+    // It returns the guard page of the current task or 0 if that
+    // guard page doesn't exist. None is returned if there's currently
+    // no local task.
+    unsafe fn get_task_guard_page() -> Option<uint> {
+        let task: Option<*mut Task> = Local::try_unsafe_borrow();
+        task.map(|task| (&*task).stack_guard().unwrap_or(0))
+    }
+
+
+    #[no_stack_check]
+    unsafe extern fn signal_handler(signum: libc::c_int,
+                                     info: *mut siginfo,
+                                     _data: *mut libc::c_void) {
+
+        // We can not return from a SIGSEGV or SIGBUS signal.
+        // See: https://www.gnu.org/software/libc/manual/html_node/Handler-Returns.html
+
+        unsafe fn term(signum: libc::c_int) -> ! {
+            use core::mem::transmute;
+
+            signal(signum, transmute(SIG_DFL));
+            raise(signum);
+            intrinsics::abort();
+        }
+
+        // We're calling into functions with stack checks
+        stack::record_sp_limit(0);
+
+        match get_task_guard_page() {
+            Some(guard) => {
+                let addr = (*info).si_addr as uint;
+
+                if guard == 0 || addr < guard - PAGE_SIZE || addr >= guard {
+                    term(signum);
+                }
+
+                report_overflow();
+
+                intrinsics::abort()
+            }
+            None => term(signum)
+        }
+    }
+
+    static mut MAIN_ALTSTACK: *mut libc::c_void = 0 as *mut libc::c_void;
+
+    pub unsafe fn init() {
+        let psize = libc::sysconf(libc::consts::os::sysconf::_SC_PAGESIZE);
+        if psize == -1 {
+            panic!("failed to get page size");
+        }
+
+        PAGE_SIZE = psize as uint;
+
+        let mut action: sigaction = mem::zeroed();
+        action.sa_flags = SA_SIGINFO | SA_ONSTACK;
+        action.sa_sigaction = signal_handler as sighandler_t;
+        sigaction(SIGSEGV, &action, ptr::null_mut());
+        sigaction(SIGBUS, &action, ptr::null_mut());
+
+        let handler = make_handler();
+        MAIN_ALTSTACK = handler._data;
+        mem::forget(handler);
+    }
+
+    pub unsafe fn cleanup() {
+        Handler { _data: MAIN_ALTSTACK };
+    }
+
+    pub unsafe fn make_handler() -> Handler {
+        let alt_stack = mmap(ptr::null_mut(),
+                             signal::SIGSTKSZ,
+                             PROT_READ | PROT_WRITE,
+                             MAP_PRIVATE | MAP_ANON,
+                             -1,
+                             0);
+        if alt_stack == MAP_FAILED {
+            panic!("failed to allocate an alternative stack");
+        }
+
+        let mut stack: sigaltstack = mem::zeroed();
+
+        stack.ss_sp = alt_stack;
+        stack.ss_flags = 0;
+        stack.ss_size = SIGSTKSZ;
+
+        sigaltstack(&stack, ptr::null_mut());
+
+        Handler { _data: alt_stack }
+    }
+
+    pub unsafe fn drop_handler(handler: &mut Handler) {
+        munmap(handler._data, SIGSTKSZ);
+    }
+
+    type sighandler_t = *mut libc::c_void;
+
+    #[cfg(any(all(target_os = "linux", target_arch = "x86"), // may not match
+              all(target_os = "linux", target_arch = "x86_64"),
+              all(target_os = "linux", target_arch = "arm"), // may not match
+              all(target_os = "linux", target_arch = "mips"), // may not match
+              all(target_os = "linux", target_arch = "mipsel"), // may not match
+              target_os = "android"))] // may not match
+    mod signal {
+        use libc;
+        use super::sighandler_t;
+
+        pub static SA_ONSTACK: libc::c_int = 0x08000000;
+        pub static SA_SIGINFO: libc::c_int = 0x00000004;
+        pub static SIGBUS: libc::c_int = 7;
+
+        pub static SIGSTKSZ: libc::size_t = 8192;
+
+        pub static SIG_DFL: sighandler_t = 0i as sighandler_t;
+
+        // This definition is not as accurate as it could be, {si_addr} is
+        // actually a giant union. Currently we're only interested in that field,
+        // however.
+        #[repr(C)]
+        pub struct siginfo {
+            si_signo: libc::c_int,
+            si_errno: libc::c_int,
+            si_code: libc::c_int,
+            pub si_addr: *mut libc::c_void
+        }
+
+        #[repr(C)]
+        pub struct sigaction {
+            pub sa_sigaction: sighandler_t,
+            pub sa_mask: sigset_t,
+            pub sa_flags: libc::c_int,
+            sa_restorer: *mut libc::c_void,
+        }
+
+        #[cfg(target_word_size = "32")]
+        #[repr(C)]
+        pub struct sigset_t {
+            __val: [libc::c_ulong, ..32],
+        }
+        #[cfg(target_word_size = "64")]
+        #[repr(C)]
+        pub struct sigset_t {
+            __val: [libc::c_ulong, ..16],
+        }
+
+        #[repr(C)]
+        pub struct sigaltstack {
+            pub ss_sp: *mut libc::c_void,
+            pub ss_flags: libc::c_int,
+            pub ss_size: libc::size_t
+        }
+
+    }
+
+    #[cfg(target_os = "macos")]
+    mod signal {
+        use libc;
+        use super::sighandler_t;
+
+        pub const SA_ONSTACK: libc::c_int = 0x0001;
+        pub const SA_SIGINFO: libc::c_int = 0x0040;
+        pub const SIGBUS: libc::c_int = 10;
+
+        pub const SIGSTKSZ: libc::size_t = 131072;
+
+        pub const SIG_DFL: sighandler_t = 0i as sighandler_t;
+
+        pub type sigset_t = u32;
+
+        // This structure has more fields, but we're not all that interested in
+        // them.
+        #[repr(C)]
+        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,
+            pub si_addr: *mut libc::c_void
+        }
+
+        #[repr(C)]
+        pub struct sigaltstack {
+            pub ss_sp: *mut libc::c_void,
+            pub ss_size: libc::size_t,
+            pub ss_flags: libc::c_int
+        }
+
+        #[repr(C)]
+        pub struct sigaction {
+            pub sa_sigaction: sighandler_t,
+            pub sa_mask: sigset_t,
+            pub sa_flags: libc::c_int,
+        }
+    }
+
+    extern {
+        pub fn signal(signum: libc::c_int, handler: sighandler_t) -> sighandler_t;
+        pub fn raise(signum: libc::c_int) -> libc::c_int;
+
+        pub fn sigaction(signum: libc::c_int,
+                         act: *const sigaction,
+                         oldact: *mut sigaction) -> libc::c_int;
+
+        pub fn sigaltstack(ss: *const sigaltstack,
+                           oss: *mut sigaltstack) -> libc::c_int;
+    }
+}
+
+#[cfg(not(any(target_os = "linux",
+              target_os = "macos")))]
+mod imp {
+    use libc;
+
+    pub unsafe fn init() {
+    }
+
+    pub unsafe fn cleanup() {
+    }
+
+    pub unsafe fn make_handler() -> super::Handler {
+        super::Handler { _data: 0i as *mut libc::c_void }
+    }
+
+    pub unsafe fn drop_handler(_handler: &mut super::Handler) {
+    }
+}