Redirect standard descriptors for hook/notify commands

Disconnect stdin, stdout and stderr when running an external hook or
notification command. The previous solution of appending "<&- >&- 2>&-"
to the shell command line does not work if the command includes pipes.

Use shell_exec() in notify_launch_cmd() instead of a custom (and
incomplete) reimplementation of that command.

Partially addresses GitHub issue #326.

Signed-off-by: Lukas Fleischer <lfleischer@calcurse.org>

3 files changed, 11 insertions, 26 deletions

diff --git a/src/calcurse.h b/src/calcurse.h
index b006a77..ad6353c 100644
--- a/src/calcurse.h
+++ b/src/calcurse.h
@@ -671,7 +671,6 @@ struct nbar {
 	char datefmt[BUFSIZ];	/* format for displaying date */
 	char timefmt[BUFSIZ];	/* format for displaying time */
 	char cmd[BUFSIZ];	/* notification command */
-	const char *shell;	/* user shell to launch notif. cmd */
 	unsigned notify_all;	/* notify all appointments */
 	pthread_mutex_t mutex;
 };
diff --git a/src/hooks.c b/src/hooks.c
index cf1db5e..35d8a1a 100644
--- a/src/hooks.c
+++ b/src/hooks.c
@@ -41,20 +41,18 @@
 
 int run_hook(const char *name)
 {
-	char *hook_path = NULL, *hook_cmd = NULL, *mesg;
+	char *hook_path = NULL, *mesg;
+	int pid, pin, pout, perr, ret = -127;
 	char const *arg[2];
-	int pid, ret = -127;
 
 	asprintf(&hook_path, "%s/%s", path_hooks, name);
 	if (!io_file_exists(hook_path))
 		goto cleanup;
-
-	asprintf(&hook_cmd, "%s <&- >&- 2>&-", hook_path);
-	arg[0] = hook_cmd;
+	arg[0] = hook_path;
 	arg[1] = NULL;
 
-	if ((pid = shell_exec(NULL, NULL, NULL, *arg, arg))) {
-		ret = child_wait(NULL, NULL, NULL, pid);
+	if ((pid = shell_exec(&pin, &pout, &perr, *arg, arg))) {
+		ret = child_wait(&pin, &pout, &perr, pid);
 		if (ret > 0 && WIFEXITED(ret)) {
 			asprintf(&mesg, "%s hook: exit status %d",
 				 name,
@@ -71,6 +69,5 @@ int run_hook(const char *name)
 
 cleanup:
 	mem_free(hook_path);
-	mem_free(hook_cmd);
 	return ret;
 }
diff --git a/src/notify.c b/src/notify.c
index 036af0f..b73c369 100644
--- a/src/notify.c
+++ b/src/notify.c
@@ -137,9 +137,6 @@ void notify_init_vars(void)
 	strncpy(nbar.cmd, cmd, BUFSIZ);
 	nbar.cmd[BUFSIZ - 1] = '\0';
 
-	if ((nbar.shell = getenv("SHELL")) == NULL)
-		nbar.shell = "/bin/sh";
-
 	nbar.notify_all = 0;
 
 	pthread_attr_init(&detached_thread_attr);
@@ -216,26 +213,18 @@ void notify_reinit_bar(void)
 /* Launch user defined command as a notification. */
 unsigned notify_launch_cmd(void)
 {
-	int pid;
+	char const *arg[2] = { nbar.cmd, NULL };
+	int pid, pin, pout, perr;
 
 	if (notify_app.state & APOINT_NOTIFIED)
 		return 1;
 
 	notify_app.state |= APOINT_NOTIFIED;
 
-	pid = fork();
-
-	if (pid < 0) {
-		ERROR_MSG(_("error while launching command: could not fork"));
-		return 0;
-	} else if (pid == 0) {
-		/* Child: launch user defined command */
-		if (execlp(nbar.shell, nbar.shell, "-c", nbar.cmd, NULL) <
-		    0) {
-			ERROR_MSG(_("error while launching command"));
-			_exit(1);
-		}
-		_exit(0);
+	if ((pid = shell_exec(&pin, &pout, &perr, *arg, arg))) {
+		close(pin);
+		close(pout);
+		close(perr);
 	}
 
 	return 1;