alnyan/yggdrasil: add an option to change process root

library/std/src/os/yggdrasil/process.rs

@@ -7,6 +7,7 @@ use yggdrasil_rt::process::{ProcessId, Signal, SpawnFlags};
 use yggdrasil_rt::sys as syscall;
 
 use crate::io;
+use crate::path::Path;
 use crate::process::{Child, Command, ExitStatus};
 use crate::sealed::Sealed;
 use crate::sys_common::{AsInner, AsInnerMut};
@@ -28,7 +29,11 @@ pub trait CommandExt: Sealed {
     #[unstable(feature = "yggdrasil_os", issue = "none")]
     unsafe fn attach_tracing(&mut self) -> &mut Command;
 
+    #[unstable(feature = "yggdrasil_os", issue = "none")]
     fn disable_aslr(&mut self) -> &mut Command;
+
+    #[unstable(feature = "yggdrasil_os", issue = "none")]
+    fn change_root<P: AsRef<Path>>(&mut self, new: P) -> &mut Command;
 }
 
 #[unstable(feature = "yggdrasil_os", issue = "none")]
@@ -58,6 +63,11 @@ impl CommandExt for Command {
         self.as_inner_mut().flags |= SpawnFlags::DISABLE_ASLR;
         self
     }
+
+    fn change_root<P: AsRef<Path>>(&mut self, new: P) -> &mut Command {
+        self.as_inner_mut().change_root(new);
+        self
+    }
 }
 
 #[unstable(feature = "yggdrasil_os", issue = "none")]

library/std/src/sys/pal/yggdrasil/process/command.rs

@@ -17,6 +17,7 @@ pub struct Command {
     args: Vec<String>,
     env: CommandEnv,
     cwd: Option<PathBuf>,
+    pub(crate) root: Option<PathBuf>,
 
     pub(crate) pgroup: Option<OsProcessGroupId>,
     pub(crate) gain_terminal: Option<RawFd>,
@@ -39,6 +40,7 @@ impl Command {
             args: vec![],
             env: Default::default(),
             cwd: None,
+            root: None,
             pgroup: None,
             gain_terminal: None,
             attach_trace: false,
@@ -164,6 +166,7 @@ impl Command {
         }));
 
         let directory = self.cwd.as_ref().map(|cwd| cwd.to_str().unwrap());
+        let root = self.root.as_ref().map(|root| root.to_str().unwrap());
 
         let environment = &Vec::from_iter(envs.iter().map(|x| x.as_str()));
 
@@ -172,6 +175,7 @@ impl Command {
             arguments,
             environment,
             directory,
+            root,
             optional: &optional,
             flags: self.flags,
         };
@@ -180,6 +184,10 @@ impl Command {
 
         Ok(Process { pid })
     }
+
+    pub(crate) fn change_root<P: AsRef<Path>>(&mut self, root: P) {
+        self.root = Some(root.as_ref().into());
+    }
 }
 
 impl<'a> Iterator for CommandArgs<'a> {