feat: procfs mount

src/main.rs

@@ -71,8 +71,13 @@ const TESTS: &[TestSuite] = &[
     // TODO SSE/MMX/AVX states consistency
     TestSuite {
         name: "procfs",
-        desc: "",
+        desc: "Test correctness of the procfs filesystem",
         tests: &[
+            Test {
+                name: "mount",
+                desc: "Mount the procfs",
+                start: procfs::mount,
+            },
             Test {
                 name: "/proc/self/cwd",
                 desc: "/proc/self/cwd",

src/procfs.rs

@@ -1,12 +1,30 @@
-//! TODO doc
+//! procfs filesystem testing.
 
 use crate::test_assert_eq;
+use crate::util;
 use crate::util::{TestError, TestResult};
 use std::collections::HashMap;
 use std::env::current_dir;
+use std::ffi::CString;
 use std::os::unix::ffi::OsStrExt;
+use std::ptr::null;
 use std::{env, fs};
 
+pub fn mount() -> TestResult {
+    fs::create_dir_all("/proc")?;
+    let src = CString::new("procfs")?;
+    let target = CString::new("/proc")?;
+    let fstype = CString::new("tmpfs")?;
+    util::mount(
+        src.as_c_str(),
+        target.as_c_str(),
+        fstype.as_c_str(),
+        0,
+        null(),
+    )?;
+    Ok(())
+}
+
 pub fn cwd() -> TestResult {
     let cwd = fs::read_link("/proc/self/cwd")?;
     test_assert_eq!(cwd, current_dir()?);
@@ -39,7 +57,7 @@ pub fn environ() -> TestResult {
                 .enumerate()
                 .find(|(_, b)| **b == b'=')
                 .map(|(i, _)| i)
-                .ok_or_else(|| TestError("missing `=` in environment variable".to_owned()))?;
+                .ok_or_else(|| TestError("missing `=` for environment variable".to_owned()))?;
             let (name, value) = var.split_at(off);
             Ok((name, &value[1..]))
         })

src/util.rs

@@ -3,6 +3,9 @@
 use libc::mode_t;
 use std::error::Error;
 use std::ffi::c_int;
+use std::ffi::c_ulong;
+use std::ffi::c_void;
+use std::ffi::CStr;
 use std::os::unix::ffi::OsStrExt;
 use std::path::Path;
 use std::process::{Command, Stdio};
@@ -92,6 +95,21 @@ pub fn fstat(fd: c_int) -> io::Result<libc::stat> {
     }
 }
 
+pub fn mount(
+    src: &CStr,
+    target: &CStr,
+    fstype: &CStr,
+    flags: c_ulong,
+    data: *const c_void,
+) -> io::Result<()> {
+    let res = unsafe { libc::mount(src.as_ptr(), target.as_ptr(), fstype.as_ptr(), flags, data) };
+    if res >= 0 {
+        Ok(())
+    } else {
+        Err(io::Error::last_os_error())
+    }
+}
+
 /// TODO doc
 pub fn exec(cmd: &mut Command) -> TestResult {
     // TODO capture output and compare to expected output?