refactor: remove kill command, use libc

Removes the kill command call and instead uses libc to manage killing processes.

.vscode/settings.json

@@ -2,12 +2,16 @@
     "cSpell.words": [
         "DWORD",
         "Deque",
+        "EINVAL",
+        "EPERM",
+        "ESRCH",
         "MSRV",
         "Mahmoud",
         "Marcin",
         "Nonexhaustive",
         "PKGBUILD",
         "Qudsi",
+        "SIGTERM",
         "Tebibytes",
         "Ungrouped",
         "WASD",

src/app/data_harvester.rs

@@ -87,6 +87,7 @@ pub struct DataCollector {
     widgets_to_harvest: UsedWidgets,
     battery_manager: Option<Manager>,
     battery_list: Option<Vec<Battery>>,
+    #[cfg(target_os = "linux")]
     page_file_size_kb: u64,
 }
 
@@ -111,15 +112,8 @@ impl Default for DataCollector {
             widgets_to_harvest: UsedWidgets::default(),
             battery_manager: None,
             battery_list: None,
-            page_file_size_kb: {
-                #[cfg(target_os = "linux")]
-                unsafe {
-                    libc::sysconf(libc::_SC_PAGESIZE) as u64 / 1024
-                }
-
-                #[cfg(not(target_os = "linux"))]
-                0
-            },
+            #[cfg(target_os = "linux")]
+            page_file_size_kb: unsafe { libc::sysconf(libc::_SC_PAGESIZE) as u64 / 1024 },
         }
     }
 }

src/app/process_killer.rs

@@ -1,5 +1,3 @@
-use std::process::Command;
-
 // Copied from SO: https://stackoverflow.com/a/55231715
 #[cfg(target_os = "windows")]
 use winapi::{
@@ -35,12 +33,25 @@ impl Process {
 /// Kills a process, given a PID.
 pub fn kill_process_given_pid(pid: u32) -> crate::utils::error::Result<()> {
     if cfg!(target_os = "linux") || cfg!(target_os = "macos") {
-        // FIXME: Use libc instead of a command...
-        let output = Command::new("kill").arg(pid.to_string()).output()?;
-        if !(output.status).success() {
-            return Err(BottomError::GenericError(
-                std::str::from_utf8(&output.stderr)?.to_string(),
-            ));
+        #[cfg(any(target_os = "linux", target_os = "macos"))]
+        {
+            let output = unsafe { libc::kill(pid as i32, libc::SIGTERM) };
+            if output != 0 {
+                // We had an error...
+                let err_code = std::io::Error::last_os_error().raw_os_error();
+                let err = match err_code {
+                Some(libc::ESRCH) => "the target process did not exist.",
+                Some(libc::EPERM) => "the calling process does not have the permissions to terminate the target process(es).",
+                Some(libc::EINVAL) => "an invalid signal was specified.",
+                _ => "Unknown error occurred."
+            };
+
+                return Err(BottomError::GenericError(format!(
+                    "Error code {} - {}",
+                    err_code.unwrap_or(-1),
+                    err,
+                )));
+            }
         }
     } else if cfg!(target_os = "windows") {
         #[cfg(target_os = "windows")]

src/canvas/dialogs/dd_dialog.rs

@@ -24,7 +24,8 @@ impl KillDialog for Painter {
         if let Some(dd_err) = &app_state.dd_err {
             return Some(vec![
                 Text::raw("\n"),
-                Text::raw(format!("Failure to properly kill the process - {}", dd_err)),
+                Text::raw(format!("Failed to kill process.\n{}\n", dd_err)),
+                Text::raw("Please press ENTER or ESC to close this dialog."),
             ]);
         } else if let Some(to_kill_processes) = app_state.get_to_delete_processes() {
             if let Some(first_pid) = to_kill_processes.1.first() {