auto merge of #11762 : alexcrichton/rust/guard_pages, r=alexcrichton

Rebasing of the previous PRs, I believe I've found the problems.

3 files changed, 132 insertions, 68 deletions

diff --git a/src/libstd/libc.rs b/src/libstd/libc.rs
index a398835824b..d5f185880fa 100644
--- a/src/libstd/libc.rs
+++ b/src/libstd/libc.rs
@@ -2863,6 +2863,7 @@ pub mod consts {
             pub static MAP_PRIVATE : c_int = 0x0002;
             pub static MAP_FIXED : c_int = 0x0010;
             pub static MAP_ANON : c_int = 0x1000;
+            pub static MAP_STACK : c_int = 0;
 
             pub static MAP_FAILED : *c_void = -1 as *c_void;
 
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 1b55427fc2d..457d58ae464 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -33,13 +33,13 @@ use container::Container;
 #[cfg(target_os = "macos")]
 use iter::range;
 use libc;
-use libc::{c_char, c_void, c_int, size_t};
+use libc::{c_char, c_void, c_int};
 use option::{Some, None};
 use os;
 use prelude::*;
 use ptr;
 use str;
-use to_str;
+use fmt;
 use unstable::finally::Finally;
 use sync::atomics::{AtomicInt, INIT_ATOMIC_INT, SeqCst};
 
@@ -59,7 +59,7 @@ pub fn getcwd() -> Path {
 
     let mut buf = [0 as c_char, ..BUF_BYTES];
     unsafe {
-        if libc::getcwd(buf.as_mut_ptr(), buf.len() as size_t).is_null() {
+        if libc::getcwd(buf.as_mut_ptr(), buf.len() as libc::size_t).is_null() {
             fail!()
         }
         Path::new(CString::new(buf.as_ptr(), false))
@@ -350,14 +350,16 @@ pub fn self_exe_name() -> Option<Path> {
             let mib = ~[CTL_KERN as c_int,
                         KERN_PROC as c_int,
                         KERN_PROC_PATHNAME as c_int, -1 as c_int];
-            let mut sz: size_t = 0;
+            let mut sz: libc::size_t = 0;
             let err = sysctl(mib.as_ptr(), mib.len() as ::libc::c_uint,
-                             ptr::mut_null(), &mut sz, ptr::null(), 0u as size_t);
+                             ptr::mut_null(), &mut sz, ptr::null(),
+                             0u as libc::size_t);
             if err != 0 { return None; }
             if sz == 0 { return None; }
             let mut v: ~[u8] = vec::with_capacity(sz as uint);
             let err = sysctl(mib.as_ptr(), mib.len() as ::libc::c_uint,
-                             v.as_mut_ptr() as *mut c_void, &mut sz, ptr::null(), 0u as size_t);
+                             v.as_mut_ptr() as *mut c_void, &mut sz, ptr::null(),
+                             0u as libc::size_t);
             if err != 0 { return None; }
             if sz == 0 { return None; }
             v.set_len(sz as uint - 1); // chop off trailing NUL
@@ -593,12 +595,12 @@ pub fn last_os_error() -> ~str {
         #[cfg(target_os = "macos")]
         #[cfg(target_os = "android")]
         #[cfg(target_os = "freebsd")]
-        fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: size_t)
+        fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: libc::size_t)
                       -> c_int {
             #[nolink]
             extern {
-                fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: size_t)
-                              -> c_int;
+                fn strerror_r(errnum: c_int, buf: *mut c_char,
+                              buflen: libc::size_t) -> c_int;
             }
             unsafe {
                 strerror_r(errnum, buf, buflen)
@@ -609,12 +611,13 @@ pub fn last_os_error() -> ~str {
         // and requires macros to instead use the POSIX compliant variant.
         // So we just use __xpg_strerror_r which is always POSIX compliant
         #[cfg(target_os = "linux")]
-        fn strerror_r(errnum: c_int, buf: *mut c_char, buflen: size_t) -> c_int {
+        fn strerror_r(errnum: c_int, buf: *mut c_char,
+                      buflen: libc::size_t) -> c_int {
             #[nolink]
             extern {
                 fn __xpg_strerror_r(errnum: c_int,
                                     buf: *mut c_char,
-                                    buflen: size_t)
+                                    buflen: libc::size_t)
                                     -> c_int;
             }
             unsafe {
@@ -626,7 +629,7 @@ pub fn last_os_error() -> ~str {
 
         let p = buf.as_mut_ptr();
         unsafe {
-            if strerror_r(errno() as c_int, p, buf.len() as size_t) < 0 {
+            if strerror_r(errno() as c_int, p, buf.len() as libc::size_t) < 0 {
                 fail!("strerror_r failure");
             }
 
@@ -829,13 +832,14 @@ pub fn page_size() -> uint {
     }
 }
 
-/// A memory mapped file or chunk of memory. This is a very system-specific interface to the OS's
-/// memory mapping facilities (`mmap` on POSIX, `VirtualAlloc`/`CreateFileMapping` on win32). It
-/// makes no attempt at abstracting platform differences, besides in error values returned. Consider
+/// A memory mapped file or chunk of memory. This is a very system-specific
+/// interface to the OS's memory mapping facilities (`mmap` on POSIX,
+/// `VirtualAlloc`/`CreateFileMapping` on win32). It makes no attempt at
+/// abstracting platform differences, besides in error values returned. Consider
 /// yourself warned.
 ///
-/// The memory map is released (unmapped) when the destructor is run, so don't let it leave scope by
-/// accident if you want it to stick around.
+/// The memory map is released (unmapped) when the destructor is run, so don't
+/// let it leave scope by accident if you want it to stick around.
 pub struct MemoryMap {
     /// Pointer to the memory created or modified by this map.
     data: *mut u8,
@@ -847,11 +851,12 @@ pub struct MemoryMap {
 
 /// Type of memory map
 pub enum MemoryMapKind {
-    /// Memory-mapped file. On Windows, the inner pointer is a handle to the mapping, and
-    /// corresponds to `CreateFileMapping`. Elsewhere, it is null.
+    /// Virtual memory map. Usually used to change the permissions of a given
+    /// chunk of memory.  Corresponds to `VirtualAlloc` on Windows.
     MapFile(*u8),
-    /// Virtual memory map. Usually used to change the permissions of a given chunk of memory.
-    /// Corresponds to `VirtualAlloc` on Windows.
+    /// Virtual memory map. Usually used to change the permissions of a given
+    /// chunk of memory, or for allocation. Corresponds to `VirtualAlloc` on
+    /// Windows.
     MapVirtual
 }
 
@@ -863,81 +868,119 @@ pub enum MapOption {
     MapWritable,
     /// The memory should be executable
     MapExecutable,
-    /// Create a map for a specific address range. Corresponds to `MAP_FIXED` on POSIX.
+    /// Create a map for a specific address range. Corresponds to `MAP_FIXED` on
+    /// POSIX.
     MapAddr(*u8),
     /// Create a memory mapping for a file with a given fd.
     MapFd(c_int),
-    /// When using `MapFd`, the start of the map is `uint` bytes from the start of the file.
-    MapOffset(uint)
+    /// When using `MapFd`, the start of the map is `uint` bytes from the start
+    /// of the file.
+    MapOffset(uint),
+    /// On POSIX, this can be used to specify the default flags passed to
+    /// `mmap`. By default it uses `MAP_PRIVATE` and, if not using `MapFd`,
+    /// `MAP_ANON`. This will override both of those. This is platform-specific
+    /// (the exact values used) and ignored on Windows.
+    MapNonStandardFlags(c_int),
 }
 
 /// Possible errors when creating a map.
 pub enum MapError {
     /// ## The following are POSIX-specific
     ///
-    /// fd was not open for reading or, if using `MapWritable`, was not open for writing.
+    /// fd was not open for reading or, if using `MapWritable`, was not open for
+    /// writing.
     ErrFdNotAvail,
     /// fd was not valid
     ErrInvalidFd,
-    /// Either the address given by `MapAddr` or offset given by `MapOffset` was not a multiple of
-    /// `MemoryMap::granularity` (unaligned to page size).
+    /// Either the address given by `MapAddr` or offset given by `MapOffset` was
+    /// not a multiple of `MemoryMap::granularity` (unaligned to page size).
     ErrUnaligned,
     /// With `MapFd`, the fd does not support mapping.
     ErrNoMapSupport,
-    /// If using `MapAddr`, the address + `min_len` was outside of the process's address space. If
-    /// using `MapFd`, the target of the fd didn't have enough resources to fulfill the request.
+    /// If using `MapAddr`, the address + `min_len` was outside of the process's
+    /// address space. If using `MapFd`, the target of the fd didn't have enough
+    /// resources to fulfill the request.
     ErrNoMem,
+    /// A zero-length map was requested. This is invalid according to
+    /// [POSIX](http://pubs.opengroup.org/onlinepubs/9699919799/functions/mmap.html).
+    /// Not all platforms obey this, but this wrapper does.
+    ErrZeroLength,
     /// Unrecognized error. The inner value is the unrecognized errno.
     ErrUnknown(int),
     /// ## The following are win32-specific
     ///
-    /// Unsupported combination of protection flags (`MapReadable`/`MapWritable`/`MapExecutable`).
+    /// Unsupported combination of protection flags
+    /// (`MapReadable`/`MapWritable`/`MapExecutable`).
     ErrUnsupProt,
-    /// When using `MapFd`, `MapOffset` was given (Windows does not support this at all)
+    /// When using `MapFd`, `MapOffset` was given (Windows does not support this
+    /// at all)
     ErrUnsupOffset,
     /// When using `MapFd`, there was already a mapping to the file.
     ErrAlreadyExists,
-    /// Unrecognized error from `VirtualAlloc`. The inner value is the return value of GetLastError.
+    /// Unrecognized error from `VirtualAlloc`. The inner value is the return
+    /// value of GetLastError.
     ErrVirtualAlloc(uint),
-    /// Unrecognized error from `CreateFileMapping`. The inner value is the return value of
-    /// `GetLastError`.
+    /// Unrecognized error from `CreateFileMapping`. The inner value is the
+    /// return value of `GetLastError`.
     ErrCreateFileMappingW(uint),
-    /// Unrecognized error from `MapViewOfFile`. The inner value is the return value of
-    /// `GetLastError`.
+    /// Unrecognized error from `MapViewOfFile`. The inner value is the return
+    /// value of `GetLastError`.
     ErrMapViewOfFile(uint)
 }
 
-impl to_str::ToStr for MapError {
-    fn to_str(&self) -> ~str {
-        match *self {
-            ErrFdNotAvail => ~"fd not available for reading or writing",
-            ErrInvalidFd => ~"Invalid fd",
-            ErrUnaligned => ~"Unaligned address, invalid flags, \
-                              negative length or unaligned offset",
-            ErrNoMapSupport=> ~"File doesn't support mapping",
-            ErrNoMem => ~"Invalid address, or not enough available memory",
-            ErrUnknown(code) => format!("Unknown error={}", code),
-            ErrUnsupProt => ~"Protection mode unsupported",
-            ErrUnsupOffset => ~"Offset in virtual memory mode is unsupported",
-            ErrAlreadyExists => ~"File mapping for specified file already exists",
-            ErrVirtualAlloc(code) => format!("VirtualAlloc failure={}", code),
-            ErrCreateFileMappingW(code) => format!("CreateFileMappingW failure={}", code),
-            ErrMapViewOfFile(code) => format!("MapViewOfFile failure={}", code)
-        }
+impl fmt::Default for MapError {
+    fn fmt(val: &MapError, out: &mut fmt::Formatter) {
+        let str = match *val {
+            ErrFdNotAvail => "fd not available for reading or writing",
+            ErrInvalidFd => "Invalid fd",
+            ErrUnaligned => {
+                "Unaligned address, invalid flags, negative length or \
+                 unaligned offset"
+            }
+            ErrNoMapSupport=> "File doesn't support mapping",
+            ErrNoMem => "Invalid address, or not enough available memory",
+            ErrUnsupProt => "Protection mode unsupported",
+            ErrUnsupOffset => "Offset in virtual memory mode is unsupported",
+            ErrAlreadyExists => "File mapping for specified file already exists",
+            ErrZeroLength => "Zero-length mapping not allowed",
+            ErrUnknown(code) => {
+                write!(out.buf, "Unknown error = {}", code);
+                return
+            },
+            ErrVirtualAlloc(code) => {
+                write!(out.buf, "VirtualAlloc failure = {}", code);
+                return
+            },
+            ErrCreateFileMappingW(code) => {
+                format!("CreateFileMappingW failure = {}", code);
+                return
+            },
+            ErrMapViewOfFile(code) => {
+                write!(out.buf, "MapViewOfFile failure = {}", code);
+                return
+            }
+        };
+        write!(out.buf, "{}", str);
     }
 }
 
 #[cfg(unix)]
 impl MemoryMap {
-    /// Create a new mapping with the given `options`, at least `min_len` bytes long.
+    /// Create a new mapping with the given `options`, at least `min_len` bytes
+    /// long. `min_len` must be greater than zero; see the note on
+    /// `ErrZeroLength`.
     pub fn new(min_len: uint, options: &[MapOption]) -> Result<MemoryMap, MapError> {
         use libc::off_t;
 
+        if min_len == 0 {
+            return Err(ErrZeroLength)
+        }
         let mut addr: *u8 = ptr::null();
         let mut prot = 0;
         let mut flags = libc::MAP_PRIVATE;
         let mut fd = -1;
         let mut offset = 0;
+        let mut custom_flags = false;
         let len = round_up(min_len, page_size());
 
         for &o in options.iter() {
@@ -953,13 +996,15 @@ impl MemoryMap {
                     flags |= libc::MAP_FILE;
                     fd = fd_;
                 },
-                MapOffset(offset_) => { offset = offset_ as off_t; }
+                MapOffset(offset_) => { offset = offset_ as off_t; },
+                MapNonStandardFlags(f) => { custom_flags = true; flags = f },
             }
         }
-        if fd == -1 { flags |= libc::MAP_ANON; }
+        if fd == -1 && !custom_flags { flags |= libc::MAP_ANON; }
 
         let r = unsafe {
-            libc::mmap(addr as *c_void, len as size_t, prot, flags, fd, offset)
+            libc::mmap(addr as *c_void, len as libc::size_t, prot, flags, fd,
+                       offset)
         };
         if r.equiv(&libc::MAP_FAILED) {
             Err(match errno() as c_int {
@@ -983,7 +1028,8 @@ impl MemoryMap {
         }
     }
 
-    /// Granularity that the offset or address must be for `MapOffset` and `MapAddr` respectively.
+    /// Granularity that the offset or address must be for `MapOffset` and
+    /// `MapAddr` respectively.
     pub fn granularity() -> uint {
         page_size()
     }
@@ -993,6 +1039,8 @@ impl MemoryMap {
 impl Drop for MemoryMap {
     /// Unmap the mapping. Fails the task if `munmap` fails.
     fn drop(&mut self) {
+        if self.len == 0 { /* workaround for dummy_stack */ return; }
+
         unsafe {
             match libc::munmap(self.data as *c_void, self.len as libc::size_t) {
                 0 => (),
@@ -1027,7 +1075,11 @@ impl MemoryMap {
                 MapExecutable => { executable = true; }
                 MapAddr(addr_) => { lpAddress = addr_ as LPVOID; },
                 MapFd(fd_) => { fd = fd_; },
-                MapOffset(offset_) => { offset = offset_; }
+                MapOffset(offset_) => { offset = offset_; },
+                MapNonStandardFlags(f) => {
+                    info!("MemoryMap::new: MapNonStandardFlags used on \
+                           Windows: {}", f)
+                }
             }
         }
 
@@ -1113,18 +1165,18 @@ impl MemoryMap {
 
 #[cfg(windows)]
 impl Drop for MemoryMap {
-    /// Unmap the mapping. Fails the task if any of `VirtualFree`, `UnmapViewOfFile`, or
-    /// `CloseHandle` fail.
+    /// Unmap the mapping. Fails the task if any of `VirtualFree`,
+    /// `UnmapViewOfFile`, or `CloseHandle` fail.
     fn drop(&mut self) {
         use libc::types::os::arch::extra::{LPCVOID, HANDLE};
         use libc::consts::os::extra::FALSE;
+        if self.len == 0 { return }
 
         unsafe {
             match self.kind {
                 MapVirtual => {
-                    if libc::VirtualFree(self.data as *mut c_void,
-                                         self.len as size_t,
-                                         libc::MEM_RELEASE) == FALSE {
+                    if libc::VirtualFree(self.data as *mut c_void, 0,
+                                         libc::MEM_RELEASE) == 0 {
                         error!("VirtualFree failed: {}", errno());
                     }
                 },
@@ -1429,7 +1481,7 @@ mod tests {
             os::MapWritable
         ]) {
             Ok(chunk) => chunk,
-            Err(msg) => fail!(msg.to_str())
+            Err(msg) => fail!("{}", msg)
         };
         assert!(chunk.len >= 16);
 
@@ -1479,7 +1531,7 @@ mod tests {
             MapOffset(size / 2)
         ]) {
             Ok(chunk) => chunk,
-            Err(msg) => fail!(msg.to_str())
+            Err(msg) => fail!("{}", msg)
         };
         assert!(chunk.len > 0);
 
diff --git a/src/libstd/rt/env.rs b/src/libstd/rt/env.rs
index f3fa482b18c..729e377e1af 100644
--- a/src/libstd/rt/env.rs
+++ b/src/libstd/rt/env.rs
@@ -10,7 +10,7 @@
 
 //! Runtime environment settings
 
-use from_str::FromStr;
+use from_str::from_str;
 use option::{Some, None};
 use os;
 
@@ -18,18 +18,25 @@ use os;
 // They are expected to be initialized once then left alone.
 
 static mut MIN_STACK: uint = 2 * 1024 * 1024;
+/// This default corresponds to 20M of cache per scheduler (at the default size).
+static mut MAX_CACHED_STACKS: uint = 10;
 static mut DEBUG_BORROW: bool = false;
 static mut POISON_ON_FREE: bool = false;
 
 pub fn init() {
     unsafe {
         match os::getenv("RUST_MIN_STACK") {
-            Some(s) => match FromStr::from_str(s) {
+            Some(s) => match from_str(s) {
                 Some(i) => MIN_STACK = i,
                 None => ()
             },
             None => ()
         }
+        match os::getenv("RUST_MAX_CACHED_STACKS") {
+            Some(max) => MAX_CACHED_STACKS = from_str(max).expect("expected positive integer in \
+                                                                   RUST_MAX_CACHED_STACKS"),
+            None => ()
+        }
         match os::getenv("RUST_DEBUG_BORROW") {
             Some(_) => DEBUG_BORROW = true,
             None => ()
@@ -45,6 +52,10 @@ pub fn min_stack() -> uint {
     unsafe { MIN_STACK }
 }
 
+pub fn max_cached_stacks() -> uint {
+    unsafe { MAX_CACHED_STACKS }
+}
+
 pub fn debug_borrow() -> bool {
     unsafe { DEBUG_BORROW }
 }