[pbs-devel] [PATCH proxmox 2/3] proxmox/tools/fs: create tmpfile helper
Dominik Csapak
d.csapak at proxmox.com
Fri Sep 25 16:13:15 CEST 2020
by factoring out the code we had in 'replace_file'
Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
proxmox/src/tools/fs.rs | 39 ++++++++++++++++++++++++---------------
1 file changed, 24 insertions(+), 15 deletions(-)
diff --git a/proxmox/src/tools/fs.rs b/proxmox/src/tools/fs.rs
index 2cd1a1b..3f96d9e 100644
--- a/proxmox/src/tools/fs.rs
+++ b/proxmox/src/tools/fs.rs
@@ -4,7 +4,7 @@ use std::ffi::CStr;
use std::fs::{File, OpenOptions};
use std::io::{self, BufRead, BufReader, Write};
use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};
-use std::path::Path;
+use std::path::{Path, PathBuf};
use std::time::Duration;
use anyhow::{bail, format_err, Error};
@@ -121,14 +121,12 @@ pub fn file_read_firstline<P: AsRef<Path>>(path: P) -> Result<String, Error> {
.map_err(|err: Error| format_err!("unable to read {:?} - {}", path, err))
}
-/// Atomically replace a file.
-///
-/// This first creates a temporary file and then rotates it in place.
-pub fn replace_file<P: AsRef<Path>>(
+/// Takes a Path and CreateOptions, creates a tmpfile from it and returns
+/// a RawFd and PathBuf for it
+pub fn make_tmp_file<P: AsRef<Path>>(
path: P,
- data: &[u8],
options: CreateOptions,
-) -> Result<(), Error> {
+) -> Result<(RawFd, PathBuf), Error> {
let path = path.as_ref();
// Note: we use mkstemp heŕe, because this worka with different
@@ -140,8 +138,6 @@ pub fn replace_file<P: AsRef<Path>>(
Err(err) => bail!("mkstemp {:?} failed: {}", template, err),
};
- let tmp_path = tmp_path.as_path();
-
// clippy bug?: from_bits_truncate is actually a const fn...
#[allow(clippy::or_fun_call)]
let mode: stat::Mode = options
@@ -149,27 +145,40 @@ pub fn replace_file<P: AsRef<Path>>(
.unwrap_or(stat::Mode::from_bits_truncate(0o644));
if let Err(err) = stat::fchmod(fd, mode) {
- let _ = unistd::unlink(tmp_path);
+ let _ = unistd::unlink(&tmp_path);
bail!("fchmod {:?} failed: {}", tmp_path, err);
}
if options.owner.is_some() || options.group.is_some() {
if let Err(err) = fchown(fd, options.owner, options.group) {
- let _ = unistd::unlink(tmp_path);
+ let _ = unistd::unlink(&tmp_path);
bail!("fchown {:?} failed: {}", tmp_path, err);
}
}
+ Ok((fd, tmp_path))
+}
+
+/// Atomically replace a file.
+///
+/// This first creates a temporary file and then rotates it in place.
+pub fn replace_file<P: AsRef<Path>>(
+ path: P,
+ data: &[u8],
+ options: CreateOptions,
+) -> Result<(), Error> {
+ let (fd, tmp_path) = make_tmp_file(&path, options)?;
+
let mut file = unsafe { File::from_raw_fd(fd) };
if let Err(err) = file.write_all(data) {
- let _ = unistd::unlink(tmp_path);
+ let _ = unistd::unlink(&tmp_path);
bail!("write failed: {}", err);
}
- if let Err(err) = std::fs::rename(tmp_path, path) {
- let _ = unistd::unlink(tmp_path);
- bail!("Atomic rename failed for file {:?} - {}", path, err);
+ if let Err(err) = std::fs::rename(&tmp_path, &path) {
+ let _ = unistd::unlink(&tmp_path);
+ bail!("Atomic rename failed for file {:?} - {}", path.as_ref(), err);
}
Ok(())
--
2.20.1
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