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

[Fabian Grünbichler]

On December 2, 2024 2:17 pm, Maximiliano Sandoval wrote:
> 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)

this one should honor the overwrite flag and not truncate
unconditionally (see below)

>                      .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)

truncate/create and create_new don't make any sense? IMHO this should
probably also honor the overwrite flag instead?

if we want to overwrite, I think setting create+truncate would be
correct, if we don't want to overwrite, only setting create_new would be
the way to go

https://doc.rust-lang.org/stable/src/std/sys/pal/unix/fs.rs.html#1144

>                  .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)

same here

>                  .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)

this is okay, provided the tape code has locked the snapshot path this
is operating in (seems to be the case after a quick glance - @Dominik?)

>                  .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)

this is in a locked context, so should be okay as well..

>              .read(true)
>              .open(&tmp_path)?;
>  
> -- 
> 2.39.5
> 
> 
> 
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