Merge pull request #48 from chr4/no_shell

Add support for --no-shell option

README.md

@@ -58,9 +58,9 @@ Call/restart `my_server` when any file in the current directory (and all subdire
 
     $ watchexec -r -s SIGKILL my_server
 
-Send a SIGHUP to the child process upon changes:
+Send a SIGHUP to the child process upon changes (Note: with using `-n | --no-shell` here, we're executing `my_server` directly, instead of wrapping it in a shell:
 
-    $ watchexec -s SIGHUP my_server
+    $ watchexec -n -s SIGHUP my_server
 
 Run `make` when any file changes, using the `.gitignore` file in the current directory to filter:
 

doc/watchexec.1

@@ -34,6 +34,10 @@ Ignores modifications from paths that do not match \fIpattern\fR\. This option c
 Sends the specified signal (e\.g\. \fBSIGKILL\fR) to the child process\. Defaults to \fBSIGTERM\fR\.
 .
 .TP
+\fB\-n\fR, \fB\-\-no\-shell\fR
+Execute command directly, do not wrap it in \fBsh -c\fR resp\. \fBcmd.exec /C\R\. This is especially useful in combination with \fB--signal\fR, as the signal is then send directly to the specified command\. While \fB--no-shell\fR is a little more performant than the default, it prevents using shell-features like pipes and redirects\.
+.
+.TP
 \fB\-i\fR, \fB\-\-ignore\fR \fIpattern\fR
 Ignores modifications from paths that match \fIpattern\fR\. This option can be specified multiple times, and a match on any pattern causes the path to be ignored\.
 .

doc/watchexec.1.html

@@ -89,6 +89,7 @@
 <dt><code>-e</code>, <code>--exts</code> <var>extensions</var></dt><dd><p>Comma-separated list of file extensions to filter by. Leading dots are allowed (.rs) are allowed. (This is a shorthand for <code>-f</code>).</p></dd>
 <dt><code>-f</code>, <code>--filter</code> <var>pattern</var></dt><dd><p>Ignores modifications from paths that do not match <var>pattern</var>. This option can be specified multiple times, where a match on any given pattern causes the path to trigger <var>command</var>.</p></dd>
 <dt><code>-s</code>, <code>--signal</code> <var>SIGNAL</var></dt><dd><p>Sends the specified signal (e.g. <code>SIGKILl</code>) to the child process. Defaults to <code>SIGTERM</code>.</p></dd>
+<dt><code>-n</code>, <code>--no-shell</code></dt><dd><p>Execute command directly, do not wrap it in <CODE>sh -c</code> resp. <code>cmd.exec /C</code>. This is especially useful in combination with <code>--signal</code>, as the signal is then send directly to the specified command. While <code>--no-shell</code> is a little more performant than the default, it prevents using shell-features like pipes and redirects.</p></dd>
 <dt><code>-i</code>, <code>--ignore</code> <var>pattern</var></dt><dd><p>Ignores modifications from paths that match <var>pattern</var>. This option can be specified multiple times, and a match on any pattern causes the path to be ignored.</p></dd>
 <dt><code>-w</code>, <code>--watch</code> <var>path</var></dt><dd><p>Monitor a specific path for changes. By default, the current working directory is watched. This may be specified multiple times, where a change in any watched directory (and subdirectories) causes <var>command</var> to be executed.</p></dd>
 <dt><code>-r</code>, <code>--restart</code></dt><dd><p>Terminates the child process group if it is still running when subsequent file modifications are detected. By default, sends <code>SIGTERM</code>; use <code>--kill</code> to send <code>SIGKILL</code>.</p></dd>

doc/watchexec.1.ronn

@@ -25,6 +25,9 @@ Ignores modifications from paths that do not match <pattern>. This option can be
 * `-s`, `--signal`:
 Sends the specified signal (e.g. `SIGKILL`) to the child process. Defaults to `SIGTERM`.
 
+* `-n`, `--no-shell`:
+Execute command directly, do not wrap it in `sh -c` resp. `cmd.exe /C`. This is especially useful in combination with `--signal`, as the signal is then send directly to the specified command. While `--no-shell` is a little more performant than the default, it prevents using shell-features like pipes and redirects.
+
 * `-i`, `--ignore` <pattern>:
 Ignores modifications from paths that match <pattern>. This option can be specified multiple times, and a match on any pattern causes the path to be ignored.
 

src/cli.rs

@@ -14,6 +14,7 @@ pub struct Args {
     pub restart: bool,
     pub debug: bool,
     pub run_initially: bool,
+    pub no_shell: bool,
     pub no_vcs_ignore: bool,
     pub once: bool,
     pub poll: bool,
@@ -102,6 +103,10 @@ pub fn get_args() -> Args {
                  .help("Forces polling mode")
                  .long("force-poll")
                  .value_name("interval"))
+        .arg(Arg::with_name("no-shell")
+                 .help("Do not wrap command in 'sh -c' resp. 'cmd.exe /C'")
+                 .short("n")
+                 .long("no-shell"))
         .arg(Arg::with_name("once").short("1").hidden(true))
         .get_matches();
 
@@ -111,9 +116,11 @@ pub fn get_args() -> Args {
     let paths = values_t!(args.values_of("path"), String).unwrap_or(vec![String::from(".")]);
 
     // Treat --kill as --signal SIGKILL (for compatibility with older syntax)
-    let signal = match args.is_present("kill") {
+    let signal = if args.is_present("kill") {
-        true => Some("SIGKILL".to_string()),
+        Some("SIGKILL".to_string())
-        false => args.value_of("signal").map(str::to_string), // Convert Option<&str> to Option<String>
+    } else {
+        // Convert Option<&str> to Option<String>
+        args.value_of("signal").map(str::to_string)
     };
 
     let mut filters = values_t!(args.values_of("filter"), String).unwrap_or(vec![]);
@@ -144,13 +151,13 @@ pub fn get_args() -> Args {
 
     if signal.is_some() && args.is_present("postpone") {
         // TODO: Error::argument_conflict() might be the better fit, usage was unclear, though
-        Error::value_validation_auto(format!("--postpone and --signal are mutually exclusive"))
+        Error::value_validation_auto("--postpone and --signal are mutually exclusive".to_string())
             .exit();
     }
 
     if signal.is_some() && args.is_present("kill") {
         // TODO: Error::argument_conflict() might be the better fit, usage was unclear, though
-        Error::value_validation_auto(format!("--kill and --signal is ambiguous.\n       Hint: Use only '--signal SIGKILL' without --kill"))
+        Error::value_validation_auto("--kill and --signal is ambiguous.\n       Hint: Use only '--signal SIGKILL' without --kill".to_string())
             .exit();
     }
 
@@ -164,6 +171,7 @@ pub fn get_args() -> Args {
         restart: args.is_present("restart"),
         debug: args.is_present("debug"),
         run_initially: !args.is_present("postpone"),
+        no_shell: args.is_present("no-shell"),
         no_vcs_ignore: args.is_present("no-vcs-ignore"),
         once: args.is_present("once"),
         poll: args.occurrences_of("poll") > 0,

src/main.rs

@@ -107,7 +107,7 @@ fn main() {
         }
 
         let mut guard = child_process.write().unwrap();
-        *guard = Some(process::spawn(&args.cmd, vec![]));
+        *guard = Some(process::spawn(&args.cmd, vec![], args.no_shell));
     }
 
     loop {
@@ -140,7 +140,7 @@ fn main() {
                 debug!("Launching child process");
                 {
                     let mut guard = child_process.write().unwrap();
-                    *guard = Some(process::spawn(&args.cmd, paths));
+                    *guard = Some(process::spawn(&args.cmd, paths, args.no_shell));
                 }
             }
 
@@ -158,7 +158,7 @@ fn main() {
                 debug!("Launching child process");
                 {
                     let mut guard = child_process.write().unwrap();
-                    *guard = Some(process::spawn(&args.cmd, paths));
+                    *guard = Some(process::spawn(&args.cmd, paths, args.no_shell));
                 }
             }
 
@@ -179,7 +179,7 @@ fn main() {
                 debug!("Launching child process");
                 {
                     let mut guard = child_process.write().unwrap();
-                    *guard = Some(process::spawn(&args.cmd, paths));
+                    *guard = Some(process::spawn(&args.cmd, paths, args.no_shell));
                 }
             }
         }

src/process.rs

@@ -1,7 +1,7 @@
 use std::path::PathBuf;
 
-pub fn spawn(cmd: &str, updated_paths: Vec<PathBuf>) -> Process {
+pub fn spawn(cmd: &str, updated_paths: Vec<PathBuf>, no_shell: bool) -> Process {
-    self::imp::Process::new(cmd, updated_paths).expect("unable to spawn process")
+    self::imp::Process::new(cmd, updated_paths, no_shell).expect("unable to spawn process")
 }
 
 pub use self::imp::Process;
@@ -24,13 +24,28 @@ mod imp {
     #[allow(unknown_lints)]
     #[allow(mutex_atomic)]
     impl Process {
-        pub fn new(cmd: &str, updated_paths: Vec<PathBuf>) -> Result<Process> {
+        pub fn new(cmd: &str, updated_paths: Vec<PathBuf>, no_shell: bool) -> Result<Process> {
             use nix::unistd::*;
             use std::io;
             use std::os::unix::process::CommandExt;
 
-            let mut command = Command::new("sh");
+            // Assemble command to run.
-            command.arg("-c").arg(cmd);
+            // This is either the first argument from cmd (if no_shell was given) or "sh".
+            // Using "sh -c" gives us features like supportin pipes and redirects,
+            // but is a little less performant and can cause trouble when using custom signals
+            // (e.g. --signal SIGHUP)
+            let mut command = if no_shell {
+                let mut split = cmd.split_whitespace();
+                let mut command = Command::new(split.next().unwrap());
+                command.args(split);
+                command
+            } else {
+                let mut command = Command::new("sh");
+                command.arg("-c").arg(cmd);
+                command
+            };
+
+            debug!("Assembled command {:?}", command);
 
             if let Some(single_path) = super::get_single_updated_path(&updated_paths) {
                 command.env("WATCHEXEC_UPDATED_PATH", single_path);
@@ -119,7 +134,7 @@ mod imp {
     }
 
     impl Process {
-        pub fn new(cmd: &str, updated_paths: Vec<PathBuf>) -> Result<Process> {
+        pub fn new(cmd: &str, updated_paths: Vec<PathBuf>, no_shell: bool) -> Result<Process> {
             use std::os::windows::io::IntoRawHandle;
 
             fn last_err() -> io::Error {
@@ -143,8 +158,23 @@ mod imp {
                 panic!("failed to set job info: {}", last_err());
             }
 
-            let mut command = Command::new("cmd.exe");
+            let mut iter_args = cmd.split_whitespace();
-            command.arg("/C").arg(cmd);
+            let arg0 = match no_shell {
+                true => iter_args.next().unwrap(),
+                false => "cmd.exe",
+            };
+
+            // TODO: There might be a better way of doing this with &str.
+            //       I've had to fall back to String, as I wasn't able to join(" ") a Vec<&str>
+            //       into a &str
+            let args: Vec<String> = match no_shell {
+                true => iter_args.map(str::to_string).collect(),
+                false => vec!["/C".to_string(), iter_args.collect::<Vec<&str>>().join(" ")],
+            };
+
+            let mut command = Command::new(arg0);
+            command.args(args);
+            debug!("Assembled command {:?}", command);
 
             if let Some(single_path) = super::get_single_updated_path(&updated_paths) {
                 command.env("WATCHEXEC_UPDATED_PATH", single_path);
@@ -241,7 +271,7 @@ mod tests {
 
     #[test]
     fn test_start() {
-        let _ = spawn("echo hi", vec![]);
+        let _ = spawn("echo hi", vec![], true);
     }
 
     #[test]