sys: fixup error types handling

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

proxmox-sys/src/fs/file.rs

@@ -106,22 +106,22 @@ pub fn file_get_json<P: AsRef<Path>>(path: P, default: Option<Value>) -> Result<
     .map_err(|err: Error| format_err!("unable to parse json from {:?} - {}", path, err))
 }
 
+/// Read the first line of a file as String in std IO error context
+pub(crate) fn read_firstline<P: AsRef<Path>>(path: P) -> Result<String, std::io::Error> {
+    let file = std::fs::File::open(path)?;
+
+    let mut reader = BufReader::new(file);
+    let mut line = String::new();
+
+    let _ = reader.read_line(&mut line)?;
+
+    Ok(line)
+}
+
 /// Read the first line of a file as String
 pub fn file_read_firstline<P: AsRef<Path>>(path: P) -> Result<String, Error> {
     let path = path.as_ref();
-
+    read_firstline(path).map_err(|err| format_err!("unable to read {path:?} - {err}"))
-    try_block!({
-        let file = std::fs::File::open(path)?;
-
-        let mut reader = BufReader::new(file);
-
-        let mut line = String::new();
-
-        let _ = reader.read_line(&mut line)?;
-
-        Ok(line)
-    })
-    .map_err(|err: Error| format_err!("unable to read {:?} - {}", path, err))
 }
 
 /// Takes a Path and CreateOptions, creates a tmpfile from it and returns

proxmox-sys/src/linux/procfs/mod.rs

@@ -13,7 +13,7 @@ use lazy_static::lazy_static;
 use nix::unistd::Pid;
 use serde::Serialize;
 
-use crate::fs::file_read_firstline;
+use crate::fs::{read_firstline, file_read_firstline};
 
 pub mod mountinfo;
 #[doc(inline)]
@@ -455,10 +455,10 @@ pub fn read_meminfo() -> Result<ProcFsMemInfo, Error> {
 
     meminfo.swapused = meminfo.swaptotal - meminfo.swapfree;
 
-    meminfo.memshared = match file_read_firstline("/sys/kernel/mm/ksm/pages_sharing") {
+    meminfo.memshared = match read_firstline("/sys/kernel/mm/ksm/pages_sharing") {
         Ok(spages_line) => spages_line.trim_end().parse::<u64>()? * 4096,
         Err(err) if err.kind() == std::io::ErrorKind::NotFound => 0,
-        Err(err) => return Err(err),
+        Err(err) => bail!("unable to get KSM pages_sharing - {err}"),
     };
 
     Ok(meminfo)