2 files changed, 53 insertions, 7 deletions

diff --git a/src/ipc/client.rs b/src/ipc/client.rs
index 094bb636..4c356355 100644
--- a/src/ipc/client.rs
+++ b/src/ipc/client.rs
@@ -1,20 +1,34 @@
 use std::io::ErrorKind;
 use std::iter::Peekable;
-use std::slice;
+use std::path::Path;
+use std::{env, slice};
 
 use anyhow::{anyhow, bail, Context};
 use niri_config::OutputName;
 use niri_ipc::socket::Socket;
 use niri_ipc::{
-    Event, KeyboardLayouts, LogicalOutput, Mode, Output, OutputConfigChanged, Overview, Request,
-    Response, Transform, Window, WindowLayout,
+    Action, Event, KeyboardLayouts, LogicalOutput, Mode, Output, OutputConfigChanged, Overview,
+    Request, Response, Transform, Window, WindowLayout,
 };
 use serde_json::json;
 
 use crate::cli::Msg;
 use crate::utils::version;
 
-pub fn handle_msg(msg: Msg, json: bool) -> anyhow::Result<()> {
+pub fn handle_msg(mut msg: Msg, json: bool) -> anyhow::Result<()> {
+    // For actions taking paths, prepend the niri CLI's working directory.
+    if let Msg::Action {
+        action:
+            Action::Screenshot { path, .. }
+            | Action::ScreenshotScreen { path, .. }
+            | Action::ScreenshotWindow { path, .. },
+    } = &mut msg
+    {
+        if let Some(path) = path {
+            ensure_absolute_path(path).context("error making the path absolute")?;
+        }
+    }
+
     let request = match &msg {
         Msg::Version => Request::Version,
         Msg::Outputs => Request::Outputs,
@@ -668,6 +682,19 @@ fn fmt_rounded(x: f64) -> String {
     }
 }
 
+fn ensure_absolute_path(path: &mut String) -> anyhow::Result<()> {
+    let p = Path::new(path);
+    if p.is_relative() {
+        let mut cwd = env::current_dir().context("error getting current working directory")?;
+        cwd.push(p);
+        match cwd.into_os_string().into_string() {
+            Ok(absolute) => *path = absolute,
+            Err(cwd) => bail!("couldn't convert absolute path to string: {cwd:?}"),
+        }
+    }
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use insta::assert_snapshot;
diff --git a/src/ipc/server.rs b/src/ipc/server.rs
index 051bccab..354023b7 100644
--- a/src/ipc/server.rs
+++ b/src/ipc/server.rs
@@ -2,7 +2,7 @@ use std::cell::RefCell;
 use std::collections::HashSet;
 use std::ffi::OsStr;
 use std::os::unix::net::{UnixListener, UnixStream};
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use std::rc::Rc;
 use std::sync::{Arc, Mutex};
 use std::{env, io, process};
@@ -17,8 +17,8 @@ use futures_util::{select_biased, AsyncBufReadExt, AsyncWrite, AsyncWriteExt, Fu
 use niri_config::OutputName;
 use niri_ipc::state::{EventStreamState, EventStreamStatePart as _};
 use niri_ipc::{
-    Event, KeyboardLayouts, OutputConfigChanged, Overview, Reply, Request, Response, WindowLayout,
-    Workspace,
+    Action, Event, KeyboardLayouts, OutputConfigChanged, Overview, Reply, Request, Response,
+    WindowLayout, Workspace,
 };
 use smithay::desktop::layer_map_for_output;
 use smithay::input::pointer::{
@@ -379,6 +379,8 @@ async fn process(ctx: &ClientCtx, request: Request) -> Reply {
             Response::PickedColor(color)
         }
         Request::Action(action) => {
+            validate_action(&action)?;
+
             let (tx, rx) = async_channel::bounded(1);
 
             let action = niri_config::Action::from(action);
@@ -451,6 +453,23 @@ async fn process(ctx: &ClientCtx, request: Request) -> Reply {
     Ok(response)
 }
 
+fn validate_action(action: &Action) -> Result<(), String> {
+    if let Action::Screenshot { path, .. }
+    | Action::ScreenshotScreen { path, .. }
+    | Action::ScreenshotWindow { path, .. } = action
+    {
+        if let Some(path) = path {
+            // Relative paths are resolved against the niri compositor's working directory, which
+            // is almost certainly not what you want.
+            if !Path::new(path).is_absolute() {
+                return Err(format!("path must be absolute: {path}"));
+            }
+        }
+    }
+
+    Ok(())
+}
+
 async fn handle_event_stream_client(client: EventStreamClient) -> anyhow::Result<()> {
     let EventStreamClient {
         events,