Remove syscall module.

This module merely contained FFI declarations, and only enough to
implement memfd_create() and pivot_root() wrapper functions in
nix. Since these declarations are redundant with equivalent FFI
declarations in libc, we'll remove them here. In the future, any
syscall-related wrapper function will be implemented directly and
utilize libc for FFI declarations as we cannot generically expose
a type-safe `syscall()` because of its variadic argument list.

5 files changed, 12 insertions, 100 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 148f0c6d..9214b7e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -52,6 +52,11 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 - Fix compilation and tests for OpenBSD targets
   ([#688](https://github.com/nix-rust/nix/pull/688))
 
+# Removed
+- The syscall module has been removed. This only exposed enough functionality for
+  `memfd_create()` and `pivot_root()`, which are still exposed as separate functions.
+  ([#747](https://github.com/nix-rust/nix/pull/747))
+
 ## [0.9.0] 2017-07-23
 
 ### Added
diff --git a/src/sys/memfd.rs b/src/sys/memfd.rs
index b9812943..056e9e43 100644
--- a/src/sys/memfd.rs
+++ b/src/sys/memfd.rs
@@ -11,8 +11,9 @@ bitflags!(
 );
 
 pub fn memfd_create(name: &CStr, flags: MemFdCreateFlag) -> Result<RawFd> {
-    use sys::syscall::{syscall, MEMFD_CREATE};
-    let res = unsafe { syscall(MEMFD_CREATE, name.as_ptr(), flags.bits()) };
+    let res = unsafe {
+        libc::syscall(libc::SYS_memfd_create, name.as_ptr(), flags.bits())
+    };
 
     Errno::result(res).map(|r| r as RawFd)
 }
diff --git a/src/sys/mod.rs b/src/sys/mod.rs
index c73a09cd..7326a2cf 100644
--- a/src/sys/mod.rs
+++ b/src/sys/mod.rs
@@ -31,9 +31,6 @@ pub mod socket;
 
 pub mod stat;
 
-#[cfg(any(target_os = "linux", target_os = "android"))]
-pub mod syscall;
-
 #[cfg(any(target_os = "linux"))]
 pub mod reboot;
 
diff --git a/src/sys/syscall.rs b/src/sys/syscall.rs
deleted file mode 100644
index 50866ca7..00000000
--- a/src/sys/syscall.rs
+++ /dev/null
@@ -1,91 +0,0 @@
-//! Indirect system call
-//!
-use libc::c_int;
-
-pub use self::arch::*;
-
-#[cfg(target_arch = "x86_64")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 155;
-    pub static MEMFD_CREATE: Syscall = 319;
-}
-
-#[cfg(target_arch = "x86")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 217;
-    pub static MEMFD_CREATE: Syscall = 356;
-}
-
-#[cfg(target_arch = "aarch64")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 41;
-    pub static MEMFD_CREATE: Syscall = 279;
-}
-
-#[cfg(target_arch = "arm")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 218;
-    pub static MEMFD_CREATE: Syscall = 385;
-}
-
-// Rust on mips uses the N32 ABI
-#[cfg(target_arch = "mips")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 216;
-    pub static MEMFD_CREATE: Syscall = 354;
-}
-
-// Rust on mips64 uses the N64 ABI
-#[cfg(target_arch = "mips64")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 151;
-    pub static MEMFD_CREATE: Syscall = 314;
-}
-
-#[cfg(any(target_arch = "powerpc", target_arch = "powerpc64"))]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 203;
-    pub static MEMFD_CREATE: Syscall = 360;
-}
-
-#[cfg(target_arch = "s390x")]
-mod arch {
-    use libc::c_long;
-
-    pub type Syscall = c_long;
-
-    pub static SYSPIVOTROOT: Syscall = 217;
-    pub static MEMFD_CREATE: Syscall = 350;
-}
-
-extern {
-    pub fn syscall(num: Syscall, ...) -> c_int;
-}
diff --git a/src/unistd.rs b/src/unistd.rs
index af38cf2d..fad51272 100644
--- a/src/unistd.rs
+++ b/src/unistd.rs
@@ -16,7 +16,7 @@ use sys::stat::Mode;
 use std::fmt;
 
 #[cfg(any(target_os = "android", target_os = "linux"))]
-pub use self::linux::*;
+pub use self::pivot_root::*;
 
 #[cfg(any(target_os = "android", target_os = "freebsd",
           target_os = "linux", target_os = "openbsd"))]
@@ -1647,8 +1647,8 @@ pub fn sysconf(var: SysconfVar) -> Result<Option<c_long>> {
 }
 
 #[cfg(any(target_os = "android", target_os = "linux"))]
-mod linux {
-    use sys::syscall::{syscall, SYSPIVOTROOT};
+mod pivot_root {
+    use libc;
     use {Errno, Result, NixPath};
 
     pub fn pivot_root<P1: ?Sized + NixPath, P2: ?Sized + NixPath>(
@@ -1656,7 +1656,7 @@ mod linux {
         let res = try!(try!(new_root.with_nix_path(|new_root| {
             put_old.with_nix_path(|put_old| {
                 unsafe {
-                    syscall(SYSPIVOTROOT, new_root.as_ptr(), put_old.as_ptr())
+                    libc::syscall(libc::SYS_pivot_root, new_root.as_ptr(), put_old.as_ptr())
                 }
             })
         })));