[pbs-devel] [PATCH backup] use truncate whenever we create files

[Maximiliano Sandoval]

Fixes the suspicious_open_options clippy lint, for example:

```
warning: file opened with `create`, but `truncate` behavior not defined
    --> src/api2/tape/restore.rs:1713:18
     |
1713 |                 .create(true)
     |                  ^^^^^^^^^^^^- help: add: `.truncate(true)`
     |
     = help: if you intend to overwrite an existing file entirely, call `.truncate(true)`
     = help: if you instead know that you may want to keep some parts of the old file, call `.truncate(false)`
     = help: alternatively, use `.append(true)` to append to the file instead of overwriting it
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_open_options
```

Signed-off-by: Maximiliano Sandoval <m.sandoval at proxmox.com>
---

Some of these are quite obvious (tmp files) but I am not 100% about all of them,
a few extra eyes on it would ne appreciated.


 pbs-client/src/pxar/extract.rs    | 1 +
 proxmox-backup-client/src/main.rs | 2 ++
 src/api2/tape/restore.rs          | 1 +
 src/server/sync.rs                | 1 +
 4 files changed, 5 insertions(+)

diff --git a/pbs-client/src/pxar/extract.rs b/pbs-client/src/pxar/extract.rs
index cfbd8d51..b3e7d535 100644
--- a/pbs-client/src/pxar/extract.rs
+++ b/pbs-client/src/pxar/extract.rs
@@ -134,6 +134,7 @@ where
             if let Some(entry) = prelude {
                 let mut prelude_file = OpenOptions::new()
                     .create(true)
+                    .truncate(true)
                     .write(true)
                     .open(path)
                     .with_context(|| format!("error creating prelude file '{path:?}'"))?;
diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index b0d45f89..9fcf35d7 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -1597,6 +1597,7 @@ async fn restore(
             let mut writer = std::fs::OpenOptions::new()
                 .write(true)
                 .create(true)
+                .truncate(true)
                 .create_new(true)
                 .open(target)
                 .map_err(|err| {
@@ -1723,6 +1724,7 @@ async fn restore(
             std::fs::OpenOptions::new()
                 .write(true)
                 .create(true)
+                .truncate(true)
                 .create_new(true)
                 .open(target)
                 .map_err(|err| format_err!("unable to create target file {:?} - {}", target, err))?
diff --git a/src/api2/tape/restore.rs b/src/api2/tape/restore.rs
index 93a6053b..2cc1baab 100644
--- a/src/api2/tape/restore.rs
+++ b/src/api2/tape/restore.rs
@@ -1711,6 +1711,7 @@ fn try_restore_snapshot_archive<R: pxar::decoder::SeqRead>(
             let mut tmpfile = std::fs::OpenOptions::new()
                 .write(true)
                 .create(true)
+                .truncate(true)
                 .read(true)
                 .open(&tmp_path)
                 .map_err(|err| format_err!("restore {:?} failed - {}", tmp_path, err))?;
diff --git a/src/server/sync.rs b/src/server/sync.rs
index 0bd7a7a8..04654c28 100644
--- a/src/server/sync.rs
+++ b/src/server/sync.rs
@@ -159,6 +159,7 @@ impl SyncSourceReader for RemoteSourceReader {
         let tmpfile = std::fs::OpenOptions::new()
             .write(true)
             .create(true)
+            .truncate(true)
             .read(true)
             .open(&tmp_path)?;
 
-- 
2.39.5