4 files changed, 169 insertions, 30 deletions

diff --git a/src/platform/fallback.rs b/src/platform/fallback.rs
index 735f7c11..7bcd23c5 100644
--- a/src/platform/fallback.rs
+++ b/src/platform/fallback.rs
@@ -1,7 +1,9 @@
 use std::path::PathBuf;
 
+use super::ForegroundJob;
+
 /// Unsupported platform stub.
-pub fn foreground_process_name(_child_pid: u32) -> Option<String> {
+pub fn foreground_job(_child_pid: u32) -> Option<ForegroundJob> {
     None
 }
 
diff --git a/src/platform/linux.rs b/src/platform/linux.rs
index 001ef03e..10695e92 100644
--- a/src/platform/linux.rs
+++ b/src/platform/linux.rs
@@ -1,8 +1,51 @@
 use std::path::PathBuf;
 
-/// Get the foreground process name for a given child PID.
-/// Uses /proc/<pid>/stat to find the tpgid, then /proc/<tpgid>/comm.
-pub fn foreground_process_name(child_pid: u32) -> Option<String> {
+use super::{ForegroundJob, ForegroundProcess};
+
+/// Collect the foreground terminal job for a given child PID.
+pub fn foreground_job(child_pid: u32) -> Option<ForegroundJob> {
+    let tpgid = foreground_pgid(child_pid)? as u32;
+    let mut processes = Vec::new();
+
+    for entry in std::fs::read_dir("/proc").ok()? {
+        let entry = entry.ok()?;
+        let file_name = entry.file_name();
+        let pid_str = file_name.to_str()?;
+        if !pid_str.bytes().all(|b| b.is_ascii_digit()) {
+            continue;
+        }
+
+        let pid: u32 = match pid_str.parse() {
+            Ok(pid) => pid,
+            Err(_) => continue,
+        };
+
+        let Some((pgrp, name)) = process_pgrp_and_comm(pid) else {
+            continue;
+        };
+        if pgrp as u32 != tpgid {
+            continue;
+        }
+
+        processes.push(ForegroundProcess {
+            pid,
+            name,
+            argv0: None,
+            cmdline: process_cmdline(pid),
+        });
+    }
+
+    if processes.is_empty() {
+        return None;
+    }
+
+    Some(ForegroundJob {
+        process_group_id: tpgid,
+        processes,
+    })
+}
+
+fn foreground_pgid(child_pid: u32) -> Option<i32> {
     // /proc/<pid>/stat format: "pid (comm) state ppid pgrp session tty_nr tpgid ..."
     // The (comm) field can contain spaces and parens, so we find the last ')' first.
     let stat = std::fs::read_to_string(format!("/proc/{child_pid}/stat")).ok()?;
@@ -10,11 +53,30 @@ pub fn foreground_process_name(child_pid: u32) -> Option<String> {
     let fields: Vec<&str> = rest.split_whitespace().collect();
     // After (comm): state(0) ppid(1) pgrp(2) session(3) tty_nr(4) tpgid(5)
     let tpgid: i32 = fields.get(5)?.parse().ok()?;
-    if tpgid <= 0 {
+    (tpgid > 0).then_some(tpgid)
+}
+
+fn process_pgrp_and_comm(pid: u32) -> Option<(i32, String)> {
+    let stat = std::fs::read_to_string(format!("/proc/{pid}/stat")).ok()?;
+    let close = stat.rfind(')')?;
+    let comm = stat.get(1 + stat.find('(')?..close)?.to_string();
+    let rest = stat.get(close + 2..)?;
+    let fields: Vec<&str> = rest.split_whitespace().collect();
+    let pgrp: i32 = fields.get(2)?.parse().ok()?;
+    Some((pgrp, comm))
+}
+
+fn process_cmdline(pid: u32) -> Option<String> {
+    let bytes = std::fs::read(format!("/proc/{pid}/cmdline")).ok()?;
+    if bytes.is_empty() {
         return None;
     }
-    let comm = std::fs::read_to_string(format!("/proc/{tpgid}/comm")).ok()?;
-    Some(comm.trim().to_string())
+    let parts: Vec<String> = bytes
+        .split(|&b| b == 0)
+        .filter(|part| !part.is_empty())
+        .map(|part| String::from_utf8_lossy(part).into_owned())
+        .collect();
+    (!parts.is_empty()).then(|| parts.join(" "))
 }
 
 /// Get the current working directory of a process.
diff --git a/src/platform/macos.rs b/src/platform/macos.rs
index f8482bba..524896d4 100644
--- a/src/platform/macos.rs
+++ b/src/platform/macos.rs
@@ -2,34 +2,60 @@ use std::ffi::OsStr;
 use std::os::unix::ffi::OsStrExt;
 use std::path::{Path, PathBuf};
 
-/// Get the foreground process name for a given child PID.
-///
-/// Uses `proc_pidinfo(PROC_PIDTBSDINFO)` to read `e_tpgid` — the foreground
-/// process group ID of the child's controlling terminal — then resolves the
-/// group leader to a human-visible name via `KERN_PROCARGS2`.
-///
-/// `KERN_PROCARGS2` reads the process's `argv[0]`, which reflects runtime
-/// title changes (e.g. Node.js `process.title = "pi"`). This matches what
-/// `ps -o comm` displays and is the only reliable way on macOS to see the
-/// effective command name for scripting runtimes.
-///
-/// Falls back to `pbi_comm` from `proc_pidinfo` if `KERN_PROCARGS2` fails.
-pub fn foreground_process_name(child_pid: u32) -> Option<String> {
+use super::{ForegroundJob, ForegroundProcess};
+
+/// Collect the foreground terminal job for a given child PID.
+pub fn foreground_job(child_pid: u32) -> Option<ForegroundJob> {
     if child_pid == 0 {
         return None;
     }
 
     let fg_pgid = foreground_pgid(child_pid)?;
+    let mut pids = vec![0i32; 4096];
+    let bytes = unsafe {
+        libc::proc_listallpids(
+            pids.as_mut_ptr() as *mut libc::c_void,
+            (pids.len() * std::mem::size_of::<i32>()) as libc::c_int,
+        )
+    };
+    if bytes <= 0 {
+        return None;
+    }
+
+    let count = (bytes as usize) / std::mem::size_of::<i32>();
+    let mut processes = Vec::new();
+
+    for raw_pid in pids.into_iter().take(count) {
+        if raw_pid <= 0 {
+            continue;
+        }
+        let pid = raw_pid as u32;
+        let Some(info) = process_bsdinfo(pid) else {
+            continue;
+        };
+        if info.pbi_pgid as u32 != fg_pgid {
+            continue;
+        }
 
-    // Primary: argv[0] via KERN_PROCARGS2 (reflects process.title changes)
-    // Note: we use the PGID as a PID — works because the group leader's PID
-    // equals the PGID. Same assumption Linux makes with /proc/{tpgid}/comm.
-    if let Some(name) = process_argv0_name(fg_pgid) {
-        return Some(name);
+        let Some(name) = comm_from_bsdinfo(&info) else {
+            continue;
+        };
+        processes.push(ForegroundProcess {
+            pid,
+            name,
+            argv0: process_argv0_name(pid),
+            cmdline: process_cmdline(pid),
+        });
+    }
+
+    if processes.is_empty() {
+        return None;
     }
 
-    // Fallback: kernel comm name from proc_pidinfo
-    process_comm_name(fg_pgid)
+    Some(ForegroundJob {
+        process_group_id: fg_pgid,
+        processes,
+    })
 }
 
 /// Read `e_tpgid` (foreground process group of the controlling terminal)
@@ -151,6 +177,10 @@ fn kern_procargs2(pid: u32) -> Option<Vec<u8>> {
 /// This is the kernel-level short command name (like `node`, `zsh`).
 /// It does NOT reflect `process.title` changes.
 fn process_comm_name(pid: u32) -> Option<String> {
+    process_bsdinfo(pid).and_then(|info| comm_from_bsdinfo(&info))
+}
+
+fn process_bsdinfo(pid: u32) -> Option<libc::proc_bsdinfo> {
     let mut info: libc::proc_bsdinfo = unsafe { std::mem::zeroed() };
     let size = std::mem::size_of::<libc::proc_bsdinfo>() as libc::c_int;
 
@@ -164,10 +194,10 @@ fn process_comm_name(pid: u32) -> Option<String> {
         )
     };
 
-    if ret != size {
-        return None;
-    }
+    (ret == size).then_some(info)
+}
 
+fn comm_from_bsdinfo(info: &libc::proc_bsdinfo) -> Option<String> {
     let end = info
         .pbi_comm
         .iter()
@@ -181,6 +211,37 @@ fn process_comm_name(pid: u32) -> Option<String> {
     String::from_utf8(bytes).ok()
 }
 
+fn process_cmdline(pid: u32) -> Option<String> {
+    let buf = kern_procargs2(pid)?;
+    if buf.len() < 4 {
+        return None;
+    }
+
+    let argc = i32::from_ne_bytes([buf[0], buf[1], buf[2], buf[3]]);
+    if argc < 1 {
+        return None;
+    }
+
+    let rest = &buf[4..];
+    let mut start = 0usize;
+    while start < rest.len() && rest[start] != 0 {
+        start += 1;
+    }
+    while start < rest.len() && rest[start] == 0 {
+        start += 1;
+    }
+    if start >= rest.len() {
+        return None;
+    }
+
+    let parts: Vec<String> = rest[start..]
+        .split(|&b| b == 0)
+        .filter(|part| !part.is_empty())
+        .map(|part| String::from_utf8_lossy(part).into_owned())
+        .collect();
+    (!parts.is_empty()).then(|| parts.join(" "))
+}
+
 /// Get the current working directory of a process.
 ///
 /// Uses `proc_pidinfo(PROC_PIDVNODEPATHINFO)` to read `pvi_cdir.vip_path`.
diff --git a/src/platform/mod.rs b/src/platform/mod.rs
index df8869c7..ade86249 100644
--- a/src/platform/mod.rs
+++ b/src/platform/mod.rs
@@ -3,6 +3,20 @@
 //! Centralizes OS-dependent behavior behind a clean boundary so core
 //! modules don't scatter `#[cfg]` branches through product logic.
 
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ForegroundProcess {
+    pub pid: u32,
+    pub name: String,
+    pub argv0: Option<String>,
+    pub cmdline: Option<String>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ForegroundJob {
+    pub process_group_id: u32,
+    pub processes: Vec<ForegroundProcess>,
+}
+
 #[cfg(target_os = "linux")]
 mod linux;
 #[cfg(target_os = "linux")]