mirror of
https://github.com/ibm-s390-linux/s390-tools.git
synced 2026-08-05 02:14:52 +00:00
6689e25865
- Remove useless type conversion in uvdevice.rs
- Replace useless comparison in hostname.rs
- Replace unnecessary unwrap patterns in pvapconfig
- Use sort_by_key instead of sort_by in pvimg example
Command line used to get the findings:
$ clippy --all-features -- --cap-lints=warn
warning: useless conversion to the same type: `u64`
--> pv_core/src/uvdevice.rs:56:28
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56 | rc = ioctl(raw_fd, cmd.try_into().unwrap(), cb.as_ptr_mut());
| ^^^^^^^^^^^^^^
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= help: consider removing `.try_into()`
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_conversion
= note: `#[warn(clippy::useless_conversion)]` on by default
warning: this comparison involving the minimum or maximum element for this type contains a case that is always true or always false
--> utils/src/hostname.rs:60:13
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60 | assert!(isize::try_from(buf_len).unwrap() <= isize::MAX);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: because `isize::MAX` is the maximum value for this type, this comparison is always true
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#absurd_extreme_comparisons
= note: `#[warn(clippy::absurd_extreme_comparisons)]` on by default
warning: `utils` (lib) generated 1 warning
Checking pvebc v0.12.0 (/home/mhartmay/git/s390-tools/rust/pvebc)
warning: consider using `sort_unstable_by_key`
--> pvapconfig/src/ap.rs:177:9
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177 | self.0.sort_unstable_by(|a, b| b.gen.cmp(&a.gen));
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_sort_by
= note: `#[warn(clippy::unnecessary_sort_by)]` on by default
help: try
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177 - self.0.sort_unstable_by(|a, b| b.gen.cmp(&a.gen));
177 + self.0.sort_unstable_by_key(|b| std::cmp::Reverse(b.gen));
warning: called `unwrap_err` on `r` after checking its variant with `is_err`
--> pvapconfig/src/main.rs:55:29
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54 | if $r.is_err() {
| -------------- help: try: `if let Err(<item>) = r`
55 | eprintln!("{}", $r.unwrap_err());
| ^^^^^^^^^^^^^^^
...
87 | on_error_print_and_exit!(r);
| --------------------------- in this macro invocation
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= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
= note: this warning originates in the macro `on_error_print_and_exit` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: this `repeat().take()` can be written more concisely
--> pvimg/src/se_img_comps/bootloader/ipl.rs:95:21
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95 | let comps = iter::repeat(ipl_pb0_pv_comp::default())
| _____________________^
96 | | .take(num_comp)
| |___________________________^ help: consider using `repeat_n()` instead: `std::iter::repeat_n(ipl_pb0_pv_comp::default(), num_comp)`
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= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_repeat_n
= note: `#[warn(clippy::manual_repeat_n)]` on by default
warning: this `repeat().take()` can be written more concisely
--> pvimg/src/se_img_comps/bootloader/ipl.rs:113:21
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113 | let comps = iter::repeat(comp).take(num_comp).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `repeat_n()` instead: `std::iter::repeat_n(comp, num_comp)`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_repeat_n
Reviewed-by: Timo Keller <tkeller@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Marc Hartmayer <marc@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
70 lines
2.1 KiB
Rust
70 lines
2.1 KiB
Rust
// SPDX-License-Identifier: MIT
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//
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// Copyright IBM Corp. 2026
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use std::ffi::CStr;
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use std::io;
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/// Returns the maximum hostname length supported by the system.
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///
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/// # Returns
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///
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/// The maximum hostname length in bytes, excluding the NUL terminator.
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fn max_hostname_len() -> usize {
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const _POSIX_HOST_NAME_MAX: usize = 255;
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// SAFETY: sysconf is safe to call with _SC_HOST_NAME_MAX and only reads system configuration
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// without side effects.
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let n = unsafe { libc::sysconf(libc::_SC_HOST_NAME_MAX) };
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if n < 0 {
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_POSIX_HOST_NAME_MAX
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} else {
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n.try_into().unwrap()
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}
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}
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/// Retrieves the system hostname using libc gethostname.
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///
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/// # Returns
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///
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/// Returns `Ok(String)` containing the hostname on success, or an `Err(io::Error)` otherwise.
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///
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/// # Examples
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///
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/// ```rust,no_run
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/// use utils::gethostname;
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///
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/// let hostname = gethostname().expect("Failed to get hostname");
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/// println!("Hostname: {}", hostname);
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/// ```
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pub fn gethostname() -> io::Result<String> {
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// Add space for NUL terminator
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let buf_len = max_hostname_len().checked_add(1).unwrap();
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let mut buf = vec![0u8; buf_len];
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// SAFETY: `buf` is a byte array large enough for storing the result of
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// `gethostname` as the max length was just checked before.
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let result = unsafe { libc::gethostname(buf.as_mut_ptr() as *mut libc::c_char, buf.len()) };
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if result != 0 {
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// libc::gethostname returns -1 on error and sets errno
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return Err(io::Error::last_os_error());
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}
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// If it is not NUL-terminated, then add the NUL-termination at the end
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if !buf.contains(&0) {
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if let Some(last) = buf.last_mut() {
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*last = 0;
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}
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}
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assert!(buf_len <= isize::MAX as usize);
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// SAFETY: We made sure that `buf` is:
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// 1. NUL-terminated
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// 2. A single allocation (vec![...] was used for the allocation)
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// 3. `buf_len` is <= isize::MAX (verified by assertion above)
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// Therefore, it's safe to construct a CStr from the buffer pointer.
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let cstr = unsafe { CStr::from_ptr(buf.as_ptr() as *const libc::c_char) };
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Ok(cstr.to_string_lossy().into_owned())
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}
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