1 files changed, 251 insertions, 0 deletions
diff --git a/library/std/src/sys/unix/args.rs b/library/std/src/sys/unix/args.rs
new file mode 100644
index 00000000000..9bc44a59482
--- /dev/null
+++ b/library/std/src/sys/unix/args.rs
@@ -0,0 +1,251 @@
+//! Global initialization and retrieval of command line arguments.
+//!
+//! On some platforms these are stored during runtime startup,
+//! and on some they are retrieved from the system on demand.
+
+#![allow(dead_code)] // runtime init functions not used during testing
+
+use crate::ffi::OsString;
+use crate::marker::PhantomData;
+use crate::vec;
+
+/// One-time global initialization.
+pub unsafe fn init(argc: isize, argv: *const *const u8) {
+    imp::init(argc, argv)
+}
+
+/// One-time global cleanup.
+pub unsafe fn cleanup() {
+    imp::cleanup()
+}
+
+/// Returns the command line arguments
+pub fn args() -> Args {
+    imp::args()
+}
+
+pub struct Args {
+    iter: vec::IntoIter<OsString>,
+    _dont_send_or_sync_me: PhantomData<*mut ()>,
+}
+
+impl Args {
+    pub fn inner_debug(&self) -> &[OsString] {
+        self.iter.as_slice()
+    }
+}
+
+impl Iterator for Args {
+    type Item = OsString;
+    fn next(&mut self) -> Option<OsString> {
+        self.iter.next()
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl ExactSizeIterator for Args {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl DoubleEndedIterator for Args {
+    fn next_back(&mut self) -> Option<OsString> {
+        self.iter.next_back()
+    }
+}
+
+#[cfg(any(
+    target_os = "linux",
+    target_os = "android",
+    target_os = "freebsd",
+    target_os = "dragonfly",
+    target_os = "netbsd",
+    target_os = "openbsd",
+    target_os = "solaris",
+    target_os = "illumos",
+    target_os = "emscripten",
+    target_os = "haiku",
+    target_os = "l4re",
+    target_os = "fuchsia",
+    target_os = "redox"
+))]
+mod imp {
+    use super::Args;
+    use crate::ffi::{CStr, OsString};
+    use crate::marker::PhantomData;
+    use crate::os::unix::prelude::*;
+    use crate::ptr;
+    use crate::sync::atomic::{AtomicIsize, AtomicPtr, Ordering};
+
+    use crate::sys_common::mutex::Mutex;
+
+    static ARGC: AtomicIsize = AtomicIsize::new(0);
+    static ARGV: AtomicPtr<*const u8> = AtomicPtr::new(ptr::null_mut());
+    // We never call `ENV_LOCK.init()`, so it is UB to attempt to
+    // acquire this mutex reentrantly!
+    static LOCK: Mutex = Mutex::new();
+
+    unsafe fn really_init(argc: isize, argv: *const *const u8) {
+        let _guard = LOCK.lock();
+        ARGC.store(argc, Ordering::Relaxed);
+        ARGV.store(argv as *mut _, Ordering::Relaxed);
+    }
+
+    #[inline(always)]
+    pub unsafe fn init(_argc: isize, _argv: *const *const u8) {
+        // On Linux-GNU, we rely on `ARGV_INIT_ARRAY` below to initialize
+        // `ARGC` and `ARGV`. But in Miri that does not actually happen so we
+        // still initialize here.
+        #[cfg(any(miri, not(all(target_os = "linux", target_env = "gnu"))))]
+        really_init(_argc, _argv);
+    }
+
+    /// glibc passes argc, argv, and envp to functions in .init_array, as a non-standard extension.
+    /// This allows `std::env::args` to work even in a `cdylib`, as it does on macOS and Windows.
+    #[cfg(all(target_os = "linux", target_env = "gnu"))]
+    #[used]
+    #[link_section = ".init_array.00099"]
+    static ARGV_INIT_ARRAY: extern "C" fn(
+        crate::os::raw::c_int,
+        *const *const u8,
+        *const *const u8,
+    ) = {
+        extern "C" fn init_wrapper(
+            argc: crate::os::raw::c_int,
+            argv: *const *const u8,
+            _envp: *const *const u8,
+        ) {
+            unsafe {
+                really_init(argc as isize, argv);
+            }
+        }
+        init_wrapper
+    };
+
+    pub unsafe fn cleanup() {
+        let _guard = LOCK.lock();
+        ARGC.store(0, Ordering::Relaxed);
+        ARGV.store(ptr::null_mut(), Ordering::Relaxed);
+    }
+
+    pub fn args() -> Args {
+        Args { iter: clone().into_iter(), _dont_send_or_sync_me: PhantomData }
+    }
+
+    fn clone() -> Vec<OsString> {
+        unsafe {
+            let _guard = LOCK.lock();
+            let argc = ARGC.load(Ordering::Relaxed);
+            let argv = ARGV.load(Ordering::Relaxed);
+            (0..argc)
+                .map(|i| {
+                    let cstr = CStr::from_ptr(*argv.offset(i) as *const libc::c_char);
+                    OsStringExt::from_vec(cstr.to_bytes().to_vec())
+                })
+                .collect()
+        }
+    }
+}
+
+#[cfg(any(target_os = "macos", target_os = "ios"))]
+mod imp {
+    use super::Args;
+    use crate::ffi::CStr;
+    use crate::marker::PhantomData;
+
+    pub unsafe fn init(_argc: isize, _argv: *const *const u8) {}
+
+    pub fn cleanup() {}
+
+    #[cfg(target_os = "macos")]
+    pub fn args() -> Args {
+        use crate::os::unix::prelude::*;
+        extern "C" {
+            // These functions are in crt_externs.h.
+            fn _NSGetArgc() -> *mut libc::c_int;
+            fn _NSGetArgv() -> *mut *mut *mut libc::c_char;
+        }
+
+        let vec = unsafe {
+            let (argc, argv) =
+                (*_NSGetArgc() as isize, *_NSGetArgv() as *const *const libc::c_char);
+            (0..argc as isize)
+                .map(|i| {
+                    let bytes = CStr::from_ptr(*argv.offset(i)).to_bytes().to_vec();
+                    OsStringExt::from_vec(bytes)
+                })
+                .collect::<Vec<_>>()
+        };
+        Args { iter: vec.into_iter(), _dont_send_or_sync_me: PhantomData }
+    }
+
+    // As _NSGetArgc and _NSGetArgv aren't mentioned in iOS docs
+    // and use underscores in their names - they're most probably
+    // are considered private and therefore should be avoided
+    // Here is another way to get arguments using Objective C
+    // runtime
+    //
+    // In general it looks like:
+    // res = Vec::new()
+    // let args = [[NSProcessInfo processInfo] arguments]
+    // for i in (0..[args count])
+    //      res.push([args objectAtIndex:i])
+    // res
+    #[cfg(target_os = "ios")]
+    pub fn args() -> Args {
+        use crate::ffi::OsString;
+        use crate::mem;
+        use crate::str;
+
+        extern "C" {
+            fn sel_registerName(name: *const libc::c_uchar) -> Sel;
+            fn objc_getClass(class_name: *const libc::c_uchar) -> NsId;
+        }
+
+        #[cfg(target_arch = "aarch64")]
+        extern "C" {
+            fn objc_msgSend(obj: NsId, sel: Sel) -> NsId;
+            #[allow(clashing_extern_declarations)]
+            #[link_name = "objc_msgSend"]
+            fn objc_msgSend_ul(obj: NsId, sel: Sel, i: libc::c_ulong) -> NsId;
+        }
+
+        #[cfg(not(target_arch = "aarch64"))]
+        extern "C" {
+            fn objc_msgSend(obj: NsId, sel: Sel, ...) -> NsId;
+            #[allow(clashing_extern_declarations)]
+            #[link_name = "objc_msgSend"]
+            fn objc_msgSend_ul(obj: NsId, sel: Sel, ...) -> NsId;
+        }
+
+        type Sel = *const libc::c_void;
+        type NsId = *const libc::c_void;
+
+        let mut res = Vec::new();
+
+        unsafe {
+            let process_info_sel = sel_registerName("processInfo\0".as_ptr());
+            let arguments_sel = sel_registerName("arguments\0".as_ptr());
+            let utf8_sel = sel_registerName("UTF8String\0".as_ptr());
+            let count_sel = sel_registerName("count\0".as_ptr());
+            let object_at_sel = sel_registerName("objectAtIndex:\0".as_ptr());
+
+            let klass = objc_getClass("NSProcessInfo\0".as_ptr());
+            let info = objc_msgSend(klass, process_info_sel);
+            let args = objc_msgSend(info, arguments_sel);
+
+            let cnt: usize = mem::transmute(objc_msgSend(args, count_sel));
+            for i in 0..cnt {
+                let tmp = objc_msgSend_ul(args, object_at_sel, i as libc::c_ulong);
+                let utf_c_str: *const libc::c_char = mem::transmute(objc_msgSend(tmp, utf8_sel));
+                let bytes = CStr::from_ptr(utf_c_str).to_bytes();
+                res.push(OsString::from(str::from_utf8(bytes).unwrap()))
+            }
+        }
+
+        Args { iter: res.into_iter(), _dont_send_or_sync_me: PhantomData }
+    }
+}