Use nix for hostname and kernel (utsname)

Cargo.toml

@@ -8,3 +8,4 @@ edition = "2021"
 [dependencies]
 regex = "1"
 systemstat = "0.1"
+nix = "0.23"

src/fields.rs

@@ -33,20 +33,10 @@ pub fn get_user_host_name(is_christmas: bool) -> Result<(String, String), String
     }
 
     // Hostname
-    let hostname_file = fs::File::open("/etc/hostname");
-
-    if hostname_file.is_err() {
-        return Err("error".to_string());
-    }
-
-    let mut hostname_file = hostname_file.unwrap();
-    let mut hostname = String::new();
-
-    let result = hostname_file.read_to_string(&mut hostname);
-
-    if result.is_err() {
-        return Err("error".to_string());
-    }
+    let mut buf = [0u8; 128];
+    let hostname_cstr = nix::unistd::gethostname(&mut buf)
+        .map_err(|_| "Failed getting hostname".to_owned())?;
+    let hostname = hostname_cstr.to_str().map_err(|_| "Failed decoding hostname")?;
 
     // Combine username and hostname into a formatted string
     let main_color: &str;
@@ -154,34 +144,10 @@ pub fn get_distro_name() -> Result<String, String> {
 }
 
 pub fn get_kernel() -> Result<String, String> {
-    let kernel_file = fs::File::open("/proc/version");
-
-    if kernel_file.is_err() {
-        return Err("Error".to_string());
-    }
-
-    let mut kernel_file = kernel_file.unwrap();
-    let mut kernel = String::new();
-
-    let result = kernel_file.read_to_string(&mut kernel);
-
-    if result.is_err() {
-        return Err("error".to_string());
-    }
-
-    let re_kernel = match_regex(&kernel,
-                                r#"(?x)
-                                Linux\sversion\s
-                                (?P<kernel_version>\S+)"#.to_string());
-
-    if re_kernel.is_none() {
-        return Err("Error".to_string());
-    }
-
-    let re_kernel = re_kernel.unwrap();
-
-    let kernel = re_kernel.name("kernel_version").unwrap().as_str();
-    Ok(format_data("kernel", kernel))
+    let uname = nix::sys::utsname::uname();
+    Ok(format_data(
+        "kernel",
+        &format!("{} {}", uname.release(), uname.machine())))
 }
 
 pub fn get_shell() -> Result<String, String> {