Check ESP space to avoid errors

Author: yasminvalim

src/filetree.rs

@@ -207,6 +207,16 @@ impl FileTree {
         Ok(Self { children })
     }
 
+    /// Total size in bytes of all files in the tree (for space checks).
+    #[cfg(any(
+        target_arch = "x86_64",
+        target_arch = "aarch64",
+        target_arch = "riscv64"
+    ))]
+    pub(crate) fn total_size(&self) -> u64 {
+        self.children.values().map(|m| m.size).sum()
+    }
+
     /// Determine the changes *from* self to the updated tree
     #[cfg(any(
         target_arch = "x86_64",

src/util.rs

@@ -1,9 +1,11 @@
 use std::collections::HashSet;
+use std::os::unix::io::AsRawFd;
 use std::path::Path;
 use std::process::Command;
 
 use anyhow::{bail, Context, Result};
 use openat_ext::OpenatDirExt;
+use rustix::fd::BorrowedFd;
 
 /// Parse an environment variable as UTF-8
 #[allow(dead_code)]
@@ -51,9 +53,18 @@ pub(crate) fn filenames(dir: &openat::Dir) -> Result<HashSet<String>> {
     Ok(ret)
 }
 
+/// Return the available space in bytes on the filesystem containing the given directory.
+/// Uses f_bavail * f_frsize from fstatvfs to avoid partial updates when the partition is full.
+pub(crate) fn available_space_bytes(dir: &openat::Dir) -> Result<u64> {
+    let fd = unsafe { BorrowedFd::borrow_raw(dir.as_raw_fd()) };
+    let st = rustix::fs::fstatvfs(fd)?;
+    Ok((st.f_bavail as u64) * (st.f_frsize as u64))
+}
+
 pub(crate) fn ensure_writable_mount<P: AsRef<Path>>(p: P) -> Result<()> {
     let p = p.as_ref();
-    let stat = rustix::fs::statvfs(p)?;
+    let stat =
+        rustix::fs::statvfs(p).map_err(|e| std::io::Error::from_raw_os_error(e.raw_os_error()))?;
     if !stat.f_flag.contains(rustix::fs::StatVfsMountFlags::RDONLY) {
         return Ok(());
     }