[Tarantool-patches] [PATCH 1/2] popen: Allow to kill process group

[Cyrill Gorcunov <gorcunov@gmail.com>]

As Alexander pointed out this might be useful
for running a pipe of programs inside shell
(i.e. popen.shell('foo | bar | baz', 'r')).

Reported-by: Alexander Turenko <alexander.turenko@tarantool.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
 src/lib/core/popen.c | 26 +++++++++++++++++++++++---
 src/lib/core/popen.h |  6 ++++++
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/src/lib/core/popen.c b/src/lib/core/popen.c
index 6b6062215..200b31b21 100644
--- a/src/lib/core/popen.c
+++ b/src/lib/core/popen.c
@@ -86,6 +86,19 @@ handle_new(struct popen_opts *opts)
 
 	assert(opts->argv != NULL && opts->nr_argv > 0);
 
+	/*
+	 * Killing group of signals allowed for a new
+	 * session only where it makes sense, otherwise
+	 * child gonna inherit group and we will be killing
+	 * ourself.
+	 */
+	if (opts->flags & POPEN_FLAG_GROUP_SIGNAL &&
+	    (opts->flags & POPEN_FLAG_SETSID) == 0) {
+		diag_set(IllegalParams,
+			 "popen: group signal without setting sid");
+		return NULL;
+	}
+
 	for (i = 0; i < opts->nr_argv; i++) {
 		if (opts->argv[i] == NULL)
 			continue;
@@ -443,10 +456,17 @@ popen_send_signal(struct popen_handle *handle, int signo)
 	if (!popen_may_pidop(handle))
 		return -1;
 
-	say_debug("popen: kill %d signo %d", handle->pid, signo);
-	ret = kill(handle->pid, signo);
+	say_debug("popen: %s %d signo %d",
+		  handle->flags & POPEN_FLAG_GROUP_SIGNAL ?
+		  "killpg" : "kill", handle->pid, signo);
+	if (handle->flags & POPEN_FLAG_GROUP_SIGNAL)
+		ret = killpg(handle->pid, signo);
+	else
+		ret = kill(handle->pid, signo);
 	if (ret < 0) {
-		diag_set(SystemError, "Unable to kill %d signo %d",
+		diag_set(SystemError, "Unable to %s %d signo %d",
+			 handle->flags & POPEN_FLAG_GROUP_SIGNAL ?
+			 "killpg" : "kill",
 			 handle->pid, signo);
 	}
 	return ret;
diff --git a/src/lib/core/popen.h b/src/lib/core/popen.h
index 9cbfed60c..f9dd0ff45 100644
--- a/src/lib/core/popen.h
+++ b/src/lib/core/popen.h
@@ -96,6 +96,12 @@ enum popen_flag_bits {
 	 */
 	POPEN_FLAG_RESTORE_SIGNALS_BIT	= 15,
 	POPEN_FLAG_RESTORE_SIGNALS	= (1 << POPEN_FLAG_RESTORE_SIGNALS_BIT),
+
+	/*
+	 * Send signal to a process group.
+	 */
+	POPEN_FLAG_GROUP_SIGNAL_BIT	= 16,
+	POPEN_FLAG_GROUP_SIGNAL		= (1 << POPEN_FLAG_GROUP_SIGNAL_BIT),
 };
 
 /**
-- 
2.20.1