From e20c0b30193bfba06cd880dd5b0e55f94e2705f8 Mon Sep 17 00:00:00 2001
From: Navid Yaghoobi <navidys@fedoraproject.org>
Date: Sun, 18 Aug 2024 17:46:17 +1000
Subject: [PATCH] added /proc/<pid>/cgroup

Signed-off-by: Navid Yaghoobi <navidys@fedoraproject.org>
---
 FEATURES.md             |  1 +
 src/lib.rs              |  1 +
 src/process_cgroup.rs   | 84 +++++++++++++++++++++++++++++++++++++++++
 test_data/fixtures.ttar |  5 +++
 4 files changed, 91 insertions(+)
 create mode 100644 src/process_cgroup.rs

diff --git a/FEATURES.md b/FEATURES.md
index 18e2664..92ebe21 100644
--- a/FEATURES.md
+++ b/FEATURES.md
@@ -1,5 +1,6 @@
 Supported Features
 * ✅ `/proc/<pid>`
+    * cgroup
     * cmdline
     * comm
     * cwd
diff --git a/src/lib.rs b/src/lib.rs
index 6c07f18..fc3cbcc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,7 @@ pub mod meminfo;
 pub mod net_dev;
 pub mod net_protocols;
 pub mod process;
+pub mod process_cgroup;
 pub mod process_io;
 pub mod process_limits;
 pub mod swaps;
diff --git a/src/process_cgroup.rs b/src/process_cgroup.rs
new file mode 100644
index 0000000..e5ef2f1
--- /dev/null
+++ b/src/process_cgroup.rs
@@ -0,0 +1,84 @@
+use serde::Serialize;
+
+use crate::{
+    error::{CollectResult, MetricError},
+    process::Process,
+    utils,
+};
+
+/// ProcessCgroup models one line from /proc/[pid]/cgroup
+#[derive(Debug, Serialize, Clone, Default)]
+pub struct ProcessCgroup {
+    pub hierarchy_id: usize,
+    pub controllers: Vec<String>,
+    pub path: String,
+}
+
+impl ProcessCgroup {
+    pub fn new() -> Self {
+        Default::default()
+    }
+}
+
+impl Process {
+    /// cgroup reads from /proc/<pid>/cgroup and returns cgroup information of the process
+    pub fn cgroup(&self) -> CollectResult<Vec<ProcessCgroup>> {
+        let mut proc_cgroups = Vec::new();
+        let proc_cgroup_path_str = format!("{:?}", self.path());
+        let proc_cgroup_file = format!("{}/cgroup", proc_cgroup_path_str.replace("\"", ""));
+
+        for line in utils::read_file_lines(&proc_cgroup_file)? {
+            let item_fields: Vec<&str> = line.trim().split(':').collect();
+            if item_fields.len() != 3 {
+                return Err(MetricError::InvalidFieldNumberError(
+                    "process cgroup".to_string(),
+                    item_fields.len(),
+                    line,
+                ));
+            }
+
+            let mut proc_cgroup = ProcessCgroup::new();
+            proc_cgroup.path = item_fields[2].trim().to_string();
+
+            match item_fields[0].parse::<usize>() {
+                Ok(v) => proc_cgroup.hierarchy_id = v,
+                Err(e) => return Err(MetricError::ParseIntError(item_fields[0].to_string(), e)),
+            }
+
+            if item_fields[1].trim() != "" {
+                proc_cgroup.controllers = item_fields[1]
+                    .trim()
+                    .split(",")
+                    .map(|c| c.to_string())
+                    .collect::<Vec<String>>()
+            }
+
+            proc_cgroups.push(proc_cgroup);
+        }
+
+        Ok(proc_cgroups)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::path::Path;
+
+    use crate::process::*;
+
+    #[test]
+    fn proc_cgroup() {
+        let proc_path = Path::new("test_data/fixtures/proc");
+        let sys_proc = collect_from(proc_path, 26231).expect("running proc 26231");
+        let sys_proc_cgroup = sys_proc.cgroup().expect("running proc 26231 cgroup stat");
+
+        assert_eq!(sys_proc_cgroup.len(), 1);
+        assert_eq!(sys_proc_cgroup[0].hierarchy_id, 1);
+        assert_eq!(sys_proc_cgroup[0].controllers.len(), 0);
+        assert_eq!(sys_proc_cgroup[0].path, "/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/vte-spawn-fd5b6c83-c316-470a-9732-4db75febce50.scope");
+
+        let sys_proc = collect_from(proc_path, 26232).expect("running proc 26232");
+        let sys_proc_cgroup = sys_proc.cgroup();
+        assert_eq!(sys_proc_cgroup.is_err(), true);
+    }
+}
diff --git a/test_data/fixtures.ttar b/test_data/fixtures.ttar
index a7c6963..231ef48 100644
--- a/test_data/fixtures.ttar
+++ b/test_data/fixtures.ttar
@@ -8,6 +8,11 @@ Mode: 755
 Directory: fixtures/proc/26231
 Mode: 755
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/proc/26231/cgroup
+Lines: 1
+1::/user.slice/user-1000.slice/user@1000.service/app.slice/app-org.gnome.Terminal.slice/vte-spawn-fd5b6c83-c316-470a-9732-4db75febce50.scope
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Path: fixtures/proc/26231/cmdline
 Lines: 1
 vimNULLBYTEtest.goNULLBYTE+10NULLBYTEEOF