[PATCH] /exec without controlling terminal

Otherwise "/exec sh </dev/tty" takes over and catgirl must effectively
be killed to stop the madness;  with this diff:

	catgirl  input| /exec sh </dev/tty
	catgirl output| /bin/sh: cannot open /dev/tty: Device not configured
	catgirl output| Process exits with status 1

Do the same for `-C/Copy', `-N/notify' and `-O/open' alike.
---
 command.c |  6 ++++++
 ui.c      |  6 ++++++
 url.c     | 12 ++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/command.c b/command.c
index 4c290fc..0ff7ce5 100644
--- a/command.c
+++ b/command.c
@@ -472,6 +472,12 @@ static void commandExec(uint id, char *params) {
 	if (pid < 0) err(EX_OSERR, "fork");
 	if (pid) return;
 
+	pid = setsid();
+	if (pid) {
+		warn("setsid");
+		_exit(EX_UNAVAILABLE);
+	}
+
 	close(STDIN_FILENO);
 	dup2(execPipe[1], STDOUT_FILENO);
 	dup2(utilPipe[1], STDERR_FILENO);
diff --git a/ui.c b/ui.c
index 1b21cc5..5284c2a 100644
--- a/ui.c
+++ b/ui.c
@@ -567,6 +567,12 @@ static void notify(uint id, const char *str) {
 	if (pid < 0) err(EX_OSERR, "fork");
 	if (pid) return;
 
+	pid = setsid();
+	if (pid) {
+		warn("setsid");
+		_exit(EX_UNAVAILABLE);
+	}
+
 	close(STDIN_FILENO);
 	dup2(utilPipe[1], STDOUT_FILENO);
 	dup2(utilPipe[1], STDERR_FILENO);
diff --git a/url.c b/url.c
index 9de2f9a..526dc42 100644
--- a/url.c
+++ b/url.c
@@ -123,6 +123,12 @@ static void urlOpen(const char *url) {
 	if (pid < 0) err(EX_OSERR, "fork");
 	if (pid) return;
 
+	pid = setsid();
+	if (pid) {
+		warn("setsid");
+		_exit(EX_UNAVAILABLE);
+	}
+
 	close(STDIN_FILENO);
 	dup2(utilPipe[1], STDOUT_FILENO);
 	dup2(utilPipe[1], STDERR_FILENO);
@@ -174,6 +180,12 @@ static void urlCopy(const char *url) {
 		return;
 	}
 
+	pid = setsid();
+	if (pid) {
+		warn("setsid");
+		_exit(EX_UNAVAILABLE);
+	}
+
 	dup2(rw[0], STDIN_FILENO);
 	dup2(utilPipe[1], STDOUT_FILENO);
 	dup2(utilPipe[1], STDERR_FILENO);
-- 
2.32.0

Applied, but without setsid return value checking. From ERRORS in
setsid(2), it doesn't seem necessary to check (and would need to
happen below the dup2 calls to go to the right place).