systemd: Do not check systemd version

The systemd version is purely informational and should not be parsed, as
documented in the [1]. Practically, systemd on OpenShift and Ubuntu has
different formats for its version. The errors will be thrown from dbus
when the user attempts to use an obsolete version.

1: https://www.freedesktop.org/software/systemd/man/latest/org.freedesktop.systemd1.html

Signed-off-by: Xuewei Niu <niuxuewei.nxw@antgroup.com>

Author: justxuewei

src/lib.rs

@@ -72,22 +72,11 @@ pub mod tests {
         child
     }
 
-    pub fn systemd_version() -> Option<usize> {
+    pub fn systemd_version() -> Option<String> {
         let output = Command::new("systemd").arg("--version").output().ok()?; // Return None if command execution fails
-
         if !output.status.success() {
             return None;
         }
-
-        let stdout = String::from_utf8_lossy(&output.stdout);
-
-        // The first line is typically like "systemd 254 (254.5-1-arch)"
-        let first_line = stdout.lines().next()?;
-        let mut words = first_line.split_whitespace();
-
-        words.next()?; // Skip the "systemd" word
-        let version_str = words.next()?; // The version number as string
-
-        version_str.parse::<usize>().ok()
+        Some(String::from_utf8_lossy(&output.stdout).to_string())
     }
 }

src/manager/systemd.rs

@@ -91,31 +91,21 @@ impl SystemdManager<'_> {
         &self.unit
     }
 
-    fn set_cpuset(
-        &self,
-        props: &mut Vec<Property>,
-        linux_cpu: &LinuxCpu,
-        systemd_version: usize,
-    ) -> Result<()> {
+    fn set_cpuset(&self, props: &mut Vec<Property>, linux_cpu: &LinuxCpu) -> Result<()> {
         if let Some(cpus) = linux_cpu.cpus().as_ref() {
-            let (id, value) = cpuset::cpus(cpus, systemd_version)?;
+            let (id, value) = cpuset::cpus(cpus)?;
             props.push((id, value.into()));
         }
 
         if let Some(mems) = linux_cpu.mems().as_ref() {
-            let (id, value) = cpuset::mems(mems, systemd_version)?;
+            let (id, value) = cpuset::mems(mems)?;
             props.push((id, value.into()));
         }
 
         Ok(())
     }
 
-    fn set_cpu(
-        &self,
-        props: &mut Vec<Property>,
-        linux_cpu: &LinuxCpu,
-        systemd_version: usize,
-    ) -> Result<()> {
+    fn set_cpu(&self, props: &mut Vec<Property>, linux_cpu: &LinuxCpu) -> Result<()> {
         if let Some(shares) = linux_cpu.shares() {
             let shares = if self.v2() {
                 conv::cpu_shares_to_cgroup_v2(shares)
@@ -130,7 +120,7 @@ impl SystemdManager<'_> {
         let quota = linux_cpu.quota().unwrap_or(0);
 
         if period != 0 {
-            let (id, value) = cpu::period(period, systemd_version)?;
+            let (id, value) = cpu::period(period)?;
             props.push((id, value.into()));
         }
 
@@ -272,11 +262,9 @@ impl Manager for SystemdManager<'_> {
     fn set(&mut self, resources: &LinuxResources) -> Result<()> {
         let mut props = vec![];
 
-        let systemd_version = self.systemd_client.systemd_version()?;
-
         if let Some(linux_cpu) = resources.cpu() {
-            self.set_cpuset(&mut props, linux_cpu, systemd_version)?;
-            self.set_cpu(&mut props, linux_cpu, systemd_version)?;
+            self.set_cpuset(&mut props, linux_cpu)?;
+            self.set_cpu(&mut props, linux_cpu)?;
         }
 
         if let Some(linux_memory) = resources.memory() {

src/systemd/cpu.rs

@@ -3,10 +3,8 @@
 // SPDX-License-Identifier: Apache-2.0 or MIT
 //
 
-use crate::systemd::error::{Error, Result};
-use crate::systemd::{
-    CPU_QUOTA_PERIOD_US, CPU_QUOTA_PER_SEC_US, CPU_SHARES, CPU_SYSTEMD_VERSION, CPU_WEIGHT,
-};
+use crate::systemd::error::Result;
+use crate::systemd::{CPU_QUOTA_PERIOD_US, CPU_QUOTA_PER_SEC_US, CPU_SHARES, CPU_WEIGHT};
 
 /// Returns the property for CPU shares.
 ///
@@ -21,11 +19,7 @@ pub fn shares(shares: u64, v2: bool) -> Result<(&'static str, u64)> {
 }
 
 /// Returns the property for CPU period.
-pub fn period(period: u64, systemd_version: usize) -> Result<(&'static str, u64)> {
-    if systemd_version < CPU_SYSTEMD_VERSION {
-        return Err(Error::ObsoleteSystemd);
-    }
-
+pub fn period(period: u64) -> Result<(&'static str, u64)> {
     Ok((CPU_QUOTA_PERIOD_US, period))
 }
 

src/systemd/cpuset.rs

@@ -6,29 +6,19 @@
 use bit_vec::BitVec;
 
 use crate::systemd::error::{Error, Result};
-use crate::systemd::{ALLOWED_CPUS, ALLOWED_MEMORY_NODES, CPUSET_SYSTEMD_VERSION};
+use crate::systemd::{ALLOWED_CPUS, ALLOWED_MEMORY_NODES};
 
 const BYTE_IN_BITS: usize = 8;
 
 /// Returns the property for cpuset CPUs.
-pub fn cpus(cpus: &str, systemd_version: usize) -> Result<(&'static str, Vec<u8>)> {
-    if systemd_version < CPUSET_SYSTEMD_VERSION {
-        return Err(Error::ObsoleteSystemd);
-    }
-
+pub fn cpus(cpus: &str) -> Result<(&'static str, Vec<u8>)> {
     let mask = convert_list_to_mask(cpus)?;
-
     Ok((ALLOWED_CPUS, mask))
 }
 
 /// Returns the property for cpuset memory nodes.
-pub fn mems(mems: &str, systemd_version: usize) -> Result<(&'static str, Vec<u8>)> {
-    if systemd_version < CPUSET_SYSTEMD_VERSION {
-        return Err(Error::ObsoleteSystemd);
-    }
-
+pub fn mems(mems: &str) -> Result<(&'static str, Vec<u8>)> {
     let mask = convert_list_to_mask(mems)?;
-
     Ok((ALLOWED_MEMORY_NODES, mask))
 }
 

src/systemd/dbus/client.rs

@@ -144,18 +144,9 @@ impl SystemdClient<'_> {
     }
 
     /// Get the systemd version.
-    pub fn systemd_version(&self) -> Result<usize> {
+    pub fn systemd_version(&self) -> Result<String> {
         let sys_proxy = systemd_manager_proxy()?;
-
-        // Parse 249 from "249.11-0ubuntu3.16"
-        let version = sys_proxy.version()?;
-        let version = version
-            .split('.')
-            .next()
-            .and_then(|v| v.parse::<usize>().ok())
-            .ok_or(Error::CorruptedSystemdVersion(version))?;
-
-        Ok(version)
+        Ok(sys_proxy.version()?)
     }
 
     /// Check if the unit exists.
@@ -216,7 +207,7 @@ pub mod tests {
     use crate::systemd::props::PropertiesBuilder;
     use crate::systemd::utils::expand_slice;
     use crate::systemd::{DEFAULT_DESCRIPTION, DESCRIPTION, PIDS};
-    use crate::tests::{spawn_sleep_inf, spawn_yes, systemd_version};
+    use crate::tests::{spawn_sleep_inf, spawn_yes};
 
     const TEST_SLICE: &str = "cgroupsrs-test.slice";
 
@@ -504,19 +495,6 @@ pub mod tests {
         child.wait().unwrap();
     }
 
-    #[test]
-    fn test_systemd_version() {
-        skip_if_no_systemd!();
-
-        let unit = test_unit();
-        let props = PropertiesBuilder::default_cgroup(TEST_SLICE, &unit).build();
-        let cgroup = SystemdClient::new(&unit, props).unwrap();
-        let version = cgroup.systemd_version().unwrap();
-
-        let expected_version = systemd_version().unwrap();
-        assert_eq!(version, expected_version, "Systemd version mismatch");
-    }
-
     #[test]
     fn test_exists() {
         skip_if_no_systemd!();

src/systemd/dbus/error.rs

@@ -12,7 +12,4 @@ pub enum Error {
 
     #[error("dbus error: {0}")]
     Dbus(#[from] zbus::Error),
-
-    #[error("corrupted systemd version: {0}")]
-    CorruptedSystemdVersion(String),
 }

src/systemd/error.rs

@@ -10,9 +10,6 @@ pub enum Error {
     #[error("invalid argument")]
     InvalidArgument,
 
-    #[error("obsolete systemd, please upgrade your systemd")]
-    ObsoleteSystemd,
-
     #[error("resource not supported by cgroups v1")]
     CgroupsV1NotSupported,
 }

src/systemd/mod.rs

@@ -20,6 +20,3 @@ pub const DEFAULT_SLICE: &str = "system.slice";
 
 pub const SLICE_SUFFIX: &str = ".slice";
 pub const SCOPE_SUFFIX: &str = ".scope";
-
-pub const CPU_SYSTEMD_VERSION: usize = 242;
-pub const CPUSET_SYSTEMD_VERSION: usize = 244;