deps: update nix and other dependencies

`fork` is now marked as unsafe (nix-rust/nix#1030)

agreety/Cargo.toml

@@ -10,7 +10,7 @@ repository = "https://git.sr.ht/~kennylevinsen/greetd/"
 [dependencies]
 greetd_ipc = { path = "../greetd_ipc", features = ["sync-codec"]}
 inish = { path = "../inish"}
-rpassword = "4.0"
+rpassword = "5.0"
 getopts = "0.2"
 enquote = "1.0.3"
-nix = "0.17"
+nix = "0.19"

greetd/Cargo.toml

@@ -11,9 +11,9 @@ repository = "https://git.sr.ht/~kennylevinsen/greetd/"
 debug = []
 
 [dependencies]
-nix = "0.17"
+nix = "0.19"
 pam-sys = "0.5.6"
-users = "0.9.1"
+users = "0.11.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 greetd_ipc = { path = "../greetd_ipc", features = ["tokio-codec"] }

greetd/src/session/interface.rs

@@ -105,7 +105,7 @@ impl Session {
         let cur_exe = std::env::current_exe()?;
         let bin = CString::new(cur_exe.to_str().expect("unable to get current exe name"))?;
 
-        let child = match fork().map_err(|e| format!("unable to fork: {}", e))? {
+        let child = match unsafe { fork() }.map_err(|e| format!("unable to fork: {}", e))? {
             ForkResult::Parent { child, .. } => child,
             ForkResult::Child => {
                 execv(

greetd/src/session/worker.rs

@@ -225,7 +225,7 @@ fn worker(sock: &UnixDatagram) -> Result<(), Error> {
     // PAM is weird and gets upset if you exec from the process that opened
     // the session, registering it automatically as a log-out. Thus, we must
     // exec in a new child.
-    let child = match fork().map_err(|e| format!("unable to fork: {}", e))? {
+    let child = match unsafe { fork() }.map_err(|e| format!("unable to fork: {}", e))? {
         ForkResult::Parent { child, .. } => child,
         ForkResult::Child => {
             // It is important that we do *not* return from here by