Auto merge of #51359 - cramertj:fdio_spawn, r=sfackler

[fuchsia] Migrate from launchpad to fdio_spawn_etc

fdio_spawn_etc is the preferred way of creating processes on Fuchsia
now.

cc @abarth

src/libstd/build.rs

@@ -74,7 +74,6 @@ fn main() {
         }
         println!("cargo:rustc-link-lib=zircon");
         println!("cargo:rustc-link-lib=fdio");
-        println!("cargo:rustc-link-lib=launchpad"); // for std::process
     } else if target.contains("cloudabi") {
         if cfg!(feature = "backtrace") {
             println!("cargo:rustc-link-lib=unwind");

src/libstd/sys/unix/process/process_fuchsia.rs

@@ -56,68 +56,49 @@ impl Command {
                       -> io::Result<zx_handle_t> {
         use sys::process::zircon::*;
 
-        let job_handle = zx_job_default();
         let envp = match maybe_envp {
             Some(envp) => envp.as_ptr(),
             None => ptr::null(),
         };
 
-        // To make sure launchpad_destroy gets called on the launchpad if this function fails
-        struct LaunchpadDestructor(*mut launchpad_t);
-        impl Drop for LaunchpadDestructor {
-            fn drop(&mut self) { unsafe { launchpad_destroy(self.0); } }
-        }
-
-        // Duplicate the job handle
-        let mut job_copy: zx_handle_t = ZX_HANDLE_INVALID;
-        zx_cvt(zx_handle_duplicate(job_handle, ZX_RIGHT_SAME_RIGHTS, &mut job_copy))?;
-        // Create a launchpad
-        let mut launchpad: *mut launchpad_t = ptr::null_mut();
-        zx_cvt(launchpad_create(job_copy, self.get_argv()[0], &mut launchpad))?;
-        let launchpad_destructor = LaunchpadDestructor(launchpad);
-
-        // Set the process argv
-        zx_cvt(launchpad_set_args(launchpad, self.get_argv().len() as i32 - 1,
-                                  self.get_argv().as_ptr()))?;
-        // Setup the environment vars
-        zx_cvt(launchpad_set_environ(launchpad, envp))?;
-        zx_cvt(launchpad_add_vdso_vmo(launchpad))?;
-        // Load the executable
-        zx_cvt(launchpad_elf_load(launchpad, launchpad_vmo_from_file(self.get_argv()[0])))?;
-        zx_cvt(launchpad_load_vdso(launchpad, ZX_HANDLE_INVALID))?;
-        zx_cvt(launchpad_clone(launchpad, LP_CLONE_FDIO_NAMESPACE | LP_CLONE_FDIO_CWD))?;
+        let transfer_or_clone = |opt_fd, target_fd| if let Some(local_fd) = opt_fd {
+            fdio_spawn_action_t {
+                action: FDIO_SPAWN_ACTION_TRANSFER_FD,
+                local_fd,
+                target_fd,
+                ..Default::default()
+            }
+        } else {
+            fdio_spawn_action_t {
+                action: FDIO_SPAWN_ACTION_CLONE_FD,
+                local_fd: target_fd,
+                target_fd,
+                ..Default::default()
+            }
+        };
 
         // Clone stdin, stdout, and stderr
-        if let Some(fd) = stdio.stdin.fd() {
-            zx_cvt(launchpad_transfer_fd(launchpad, fd, 0))?;
-        } else {
-            zx_cvt(launchpad_clone_fd(launchpad, 0, 0))?;
-        }
-        if let Some(fd) = stdio.stdout.fd() {
-            zx_cvt(launchpad_transfer_fd(launchpad, fd, 1))?;
-        } else {
-            zx_cvt(launchpad_clone_fd(launchpad, 1, 1))?;
-        }
-        if let Some(fd) = stdio.stderr.fd() {
-            zx_cvt(launchpad_transfer_fd(launchpad, fd, 2))?;
-        } else {
-            zx_cvt(launchpad_clone_fd(launchpad, 2, 2))?;
-        }
+        let action1 = transfer_or_clone(stdio.stdin.fd(), 0);
+        let action2 = transfer_or_clone(stdio.stdout.fd(), 1);
+        let action3 = transfer_or_clone(stdio.stderr.fd(), 2);
+        let actions = [action1, action2, action3];
 
-        // We don't want FileDesc::drop to be called on any stdio. It would close their fds. The
-        // fds will be closed once the child process finishes.
+        // We don't want FileDesc::drop to be called on any stdio. fdio_spawn_etc
+        // always consumes transferred file descriptors.
         mem::forget(stdio);
 
         for callback in self.get_closures().iter_mut() {
             callback()?;
         }
 
-        // `launchpad_go` destroys the launchpad, so we must not
-        mem::forget(launchpad_destructor);
-
         let mut process_handle: zx_handle_t = 0;
-        let mut err_msg: *const libc::c_char = ptr::null();
-        zx_cvt(launchpad_go(launchpad, &mut process_handle, &mut err_msg))?;
+        zx_cvt(fdio_spawn_etc(
+            0,
+            FDIO_SPAWN_CLONE_JOB | FDIO_SPAWN_CLONE_LDSVC | FDIO_SPAWN_CLONE_NAMESPACE,
+            self.get_argv()[0], self.get_argv().as_ptr(), envp, 3, actions.as_ptr(),
+            &mut process_handle,
+            ptr::null_mut(),
+        ))?;
         // FIXME: See if we want to do something with that err_msg
 
         Ok(process_handle)

src/libstd/sys/unix/process/zircon.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![allow(non_camel_case_types)]
+#![allow(non_camel_case_types, unused)]
 
 use convert::TryInto;
 use io;
@@ -117,75 +117,36 @@ extern {
                               avail: *mut size_t) -> zx_status_t;
 }
 
-// From `enum special_handles` in system/ulib/launchpad/launchpad.c
-// HND_LOADER_SVC = 0
-// HND_EXEC_VMO = 1
-// HND_SEGMENTS_VMAR = 2
-const HND_SPECIAL_COUNT: c_int = 3;
-
+#[derive(Default)]
 #[repr(C)]
-pub struct launchpad_t {
-    argc: u32,
-    envc: u32,
-    args: *const c_char,
-    args_len: size_t,
-    env: *const c_char,
-    env_len: size_t,
-
-    handles: *mut zx_handle_t,
-    handles_info: *mut u32,
-    handle_count: size_t,
-    handle_alloc: size_t,
-
-    entry: zx_vaddr_t,
-    base: zx_vaddr_t,
-    vdso_base: zx_vaddr_t,
-
-    stack_size: size_t,
-
-    special_handles: [zx_handle_t; HND_SPECIAL_COUNT as usize],
-    loader_message: bool,
+pub struct fdio_spawn_action_t {
+    pub action: u32,
+    pub reserved0: u32,
+    pub local_fd: i32,
+    pub target_fd: i32,
+    pub reserved1: u64,
 }
 
 extern {
-    pub fn launchpad_create(job: zx_handle_t, name: *const c_char,
-                            lp: *mut *mut launchpad_t) -> zx_status_t;
-
-    pub fn launchpad_go(lp: *mut launchpad_t,
-                        proc_handle: *mut zx_handle_t,
-                        err_msg: *mut *const c_char) -> zx_status_t;
-
-    pub fn launchpad_destroy(lp: *mut launchpad_t);
-
-    pub fn launchpad_set_args(lp: *mut launchpad_t, argc: c_int,
-                               argv: *const *const c_char) -> zx_status_t;
-
-    pub fn launchpad_set_environ(lp: *mut launchpad_t, envp: *const *const c_char) -> zx_status_t;
-
-    pub fn launchpad_clone(lp: *mut launchpad_t, what: u32) -> zx_status_t;
-
-    pub fn launchpad_clone_fd(lp: *mut launchpad_t, fd: c_int, target_fd: c_int) -> zx_status_t;
-
-    pub fn launchpad_transfer_fd(lp: *mut launchpad_t, fd: c_int, target_fd: c_int) -> zx_status_t;
-
-    pub fn launchpad_elf_load(lp: *mut launchpad_t, vmo: zx_handle_t) -> zx_status_t;
-
-    pub fn launchpad_add_vdso_vmo(lp: *mut launchpad_t) -> zx_status_t;
+    pub fn fdio_spawn_etc(job: zx_handle_t, flags: u32, path: *const c_char,
+                          argv: *const *const c_char, envp: *const *const c_char,
+                          action_count: u64, actions: *const fdio_spawn_action_t,
+                          process: *mut zx_handle_t, err_msg: *mut c_char) -> zx_status_t;
+}
 
-    pub fn launchpad_load_vdso(lp: *mut launchpad_t, vmo: zx_handle_t) -> zx_status_t;
+// fdio_spawn_etc flags
 
-    pub fn launchpad_vmo_from_file(filename: *const c_char) -> zx_handle_t;
-}
+pub const FDIO_SPAWN_CLONE_JOB: u32 = 0x0001;
+pub const FDIO_SPAWN_CLONE_LDSVC: u32 = 0x0002;
+pub const FDIO_SPAWN_CLONE_NAMESPACE: u32 = 0x0004;
+pub const FDIO_SPAWN_CLONE_STDIO: u32 = 0x0008;
+pub const FDIO_SPAWN_CLONE_ENVIRON: u32 = 0x0010;
+pub const FDIO_SPAWN_CLONE_ALL: u32 = 0xFFFF;
 
-// Launchpad clone constants
+// fdio_spawn_etc actions
 
-pub const LP_CLONE_FDIO_NAMESPACE: u32 = 0x0001;
-pub const LP_CLONE_FDIO_CWD: u32 = 0x0002;
-// LP_CLONE_FDIO_STDIO = 0x0004
-// LP_CLONE_FDIO_ALL = 0x00FF
-// LP_CLONE_ENVIRON = 0x0100
-// LP_CLONE_DEFAULT_JOB = 0x0200
-// LP_CLONE_ALL = 0xFFFF
+pub const FDIO_SPAWN_ACTION_CLONE_FD: u32 = 0x0001;
+pub const FDIO_SPAWN_ACTION_TRANSFER_FD: u32 = 0x0002;
 
 // Errors