Working mmap.

* Also replaced syscall! with in-tree version that calls syscall_return() on result.
* Learned how to use and read strace and objdump today too.

Author: anp

.gitignore

@@ -4,5 +4,6 @@ Cargo.lock
 build
 *.a
 *.o
+*.lo
 libc-test/src/common/options.h
 rusl_failures

Cargo.toml

@@ -11,3 +11,6 @@ crate-type = ["staticlib", "dylib"]
 lazy_static = { version = "0.2.1", features = ["spin_no_std"] }
 rlibc = "1.0.0"
 syscall = "0.2.1"
+
+[profile.release]
+debug = true

musl/src/mman/mmap.c

@@ -5,13 +5,14 @@
 
 #[macro_use]
 extern crate lazy_static;
-#[macro_use]
 extern crate syscall;
 
+#[macro_use]
+pub mod syscall_mgt;
+
 pub mod malloc;
 pub mod mmap;
 pub mod string;
-pub mod syscall_mgt;
 pub mod thread;
 pub mod time;
 pub mod unistd;

src/lib.rs

@@ -1,7 +1,57 @@
-use core::mem::size_of;
-use core::usize;
+use core::isize;
 
 use c_types::*;
+use errno::{set_errno, EINVAL, ENOMEM};
+use platform::mman::*;
+use thread::vmlock::__vm_wait;
+
+#[no_mangle]
+pub unsafe extern "C" fn __mmap(start: *mut c_void,
+                                len: size_t,
+                                prot: c_int,
+                                flags: c_int,
+                                fd: c_int,
+                                off: off_t)
+                                -> *mut c_void {
+
+    if (off & (PAGE_SIZE - 1)) != 0 {
+        set_errno(EINVAL);
+        return MAP_FAILED;
+    }
+
+    if len >= isize::MAX as usize {
+        set_errno(ENOMEM);
+        return MAP_FAILED;
+    }
+
+    if flags & MAP_FIXED != 0 {
+        __vm_wait();
+    }
+
+    syscall!(MMAP, start, len, prot, flags, fd, off) as *mut c_void
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn mmap(start: *mut c_void,
+                              len: size_t,
+                              prot: c_int,
+                              flags: c_int,
+                              fd: c_int,
+                              off: off_t)
+                              -> *mut c_void {
+    __mmap(start, len, prot, flags, fd, off)
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn mmap64(start: *mut c_void,
+                                len: size_t,
+                                prot: c_int,
+                                flags: c_int,
+                                fd: c_int,
+                                off: off_t)
+                                -> *mut c_void {
+    __mmap(start, len, prot, flags, fd, off)
+}
 
 #[no_mangle]
 pub unsafe extern "C" fn madvise(address: *mut c_void, len: usize, advice: c_int) -> c_int {

src/mmap.rs

@@ -41,6 +41,7 @@ pub type ptrdiff_t = isize;
 pub type intptr_t = isize;
 pub type uintptr_t = usize;
 pub type ssize_t = isize;
+pub type off_t = i64;
 
 pub type pid_t = i32;
 pub type uid_t = u32;

src/platform/linux-x86_64/c_types.rs

@@ -1 +1,7 @@
-pub const MAP_FAILED: usize = (!1i64) as usize;
+use c_types::*;
+
+pub const PAGE_SIZE: off_t = 4096;
+
+pub const MAP_FAILED: *mut c_void = 0xffffffffffffffff as *mut c_void;
+
+pub const MAP_FIXED: c_int = 0x10;

src/platform/linux-x86_64/mman.rs

@@ -4,12 +4,60 @@ use c_types::*;
 use errno::set_errno;
 
 // from musl/src/internal/syscall_ret.c
-pub unsafe fn syscall_return(code: usize) -> isize {
+pub unsafe fn syscall_return(code: usize) -> usize {
     let max_err: usize = transmute(-4096i64);
     if code > max_err {
         set_errno(-(code as c_int));
-        -1
+        (-1isize) as usize
     } else {
         transmute(code)
     }
 }
+
+// from the syscall.rs crate, just added the return handling
+#[macro_export]
+macro_rules! syscall {
+    ($nr:ident)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall0(
+                ::syscall::nr::$nr)) );
+
+    ($nr:ident, $a1:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall1(
+                ::syscall::nr::$nr,
+                $a1 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall2(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall3(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize, $a3 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr, $a4:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall4(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize, $a3 as usize,
+                $a4 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall5(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize, $a3 as usize,
+                $a4 as usize, $a5 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall6(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize, $a3 as usize,
+                $a4 as usize, $a5 as usize, $a6 as usize)) );
+
+    ($nr:ident, $a1:expr, $a2:expr, $a3:expr, $a4:expr, $a5:expr, $a6:expr, $a7:expr)
+        => ( ::syscall_mgt::syscall_return(::syscall::syscall7(
+                ::syscall::nr::$nr,
+                $a1 as usize, $a2 as usize, $a3 as usize,
+                $a4 as usize, $a5 as usize, $a6 as usize,
+                $a7 as usize)) );
+}