From: Michael Tremer <michael.tremer@ipfire.org>
Date: Sat, 27 Mar 2021 17:34:46 +0000 (+0000)
Subject: cgroup: Implement function to kill all processes left
X-Git-Tag: 0.9.28~1285^2~455
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1b41d3b1fa09cb876e2049a504f0331bda46066c;p=pakfire.git

cgroup: Implement function to kill all processes left

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---

diff --git a/src/libpakfire/cgroup.c b/src/libpakfire/cgroup.c
index 2dfe2cbd0..8e2c713e1 100644
--- a/src/libpakfire/cgroup.c
+++ b/src/libpakfire/cgroup.c
@@ -21,6 +21,7 @@
 #include <errno.h>
 #include <linux/limits.h>
 #include <linux/magic.h>
+#include <signal.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/types.h>
@@ -325,7 +326,7 @@ int pakfire_cgroup_detach(Pakfire pakfire, const char* group, pid_t pid) {
 }
 
 static ssize_t pakfire_cgroup_procs_callback(Pakfire pakfire, const char* group,
-		int (*func)(Pakfire pakfire, pid_t pid)) {
+		int (*func)(Pakfire pakfire, pid_t pid, void* data), void* data) {
 	FILE* f = pakfire_cgroup_fopen(pakfire, group, "cgroup.procs", "r");
 	if (!f)
 		return -1;
@@ -343,7 +344,18 @@ static ssize_t pakfire_cgroup_procs_callback(Pakfire pakfire, const char* group,
 		// Increment process counter
 		num_processes++;
 
-		DEBUG(pakfire, "Read line %s\n", line);
+		// Process callback
+		if (func) {
+			// Parse PID
+			pid_t pid = strtol(line, NULL, 10);
+
+			// Call callback function
+			int r = func(pakfire, pid, data);
+			if (r) {
+				fclose(f);
+				return -r;
+			}
+		}
 	}
 
 	fclose(f);
@@ -353,5 +365,46 @@ static ssize_t pakfire_cgroup_procs_callback(Pakfire pakfire, const char* group,
 }
 
 ssize_t pakfire_cgroup_num_processes(Pakfire pakfire, const char* group) {
-	return pakfire_cgroup_procs_callback(pakfire, group, NULL);
+	return pakfire_cgroup_procs_callback(pakfire, group, NULL, NULL);
+}
+
+static int send_signal(Pakfire pakfire, pid_t pid, void* data) {
+	int* signum = (int*)data;
+
+	DEBUG(pakfire, "Sending signal %d to PID %d\n", *signum, pid);
+
+	int r = kill(pid, *signum);
+	if (r < 0 && errno != ESRCH) {
+		ERROR(pakfire, "Could not send signal %d to PID %d: %s\n",
+			*signum, pid, strerror(errno));
+		return r;
+	}
+
+	return 0;
+}
+
+int pakfire_cgroup_killall(Pakfire pakfire, const char* group) {
+	DEBUG(pakfire, "Killing all processes in cgroup %s\n", group);
+	int signum = SIGTERM;
+
+	int count = 0;
+	while (1) {
+		// Kill all processes
+		size_t num_procs = pakfire_cgroup_procs_callback(pakfire, group,
+			send_signal, &signum);
+
+		// If no processes are left, we are done
+		if (!num_procs)
+			return 0;
+
+		DEBUG(pakfire, "  %zu process(es) left\n", num_procs);
+
+		// Use SIGKILL after 5 attempts with SIGTERM
+		if (count++ > 5 && signum == SIGTERM)
+			signum = SIGKILL;
+
+		usleep(100000);
+	}
+
+	return 1;
 }
diff --git a/src/libpakfire/include/pakfire/cgroup.h b/src/libpakfire/include/pakfire/cgroup.h
index e9766a676..f474faad8 100644
--- a/src/libpakfire/include/pakfire/cgroup.h
+++ b/src/libpakfire/include/pakfire/cgroup.h
@@ -35,6 +35,8 @@ int pakfire_cgroup_detach(Pakfire pakfire, const char* group, pid_t pid);
 
 ssize_t pakfire_cgroup_num_processes(Pakfire pakfire, const char* group);
 
+int pakfire_cgroup_killall(Pakfire pakfire, const char* group);
+
 #endif
 
 #endif /* PAKFIRE_CGROUP_H */
diff --git a/tests/libpakfire/cgroup.c b/tests/libpakfire/cgroup.c
index f6cdb7b1b..8bd32c125 100644
--- a/tests/libpakfire/cgroup.c
+++ b/tests/libpakfire/cgroup.c
@@ -18,6 +18,7 @@
 #                                                                             #
 #############################################################################*/
 
+#include <signal.h>
 #include <sys/types.h>
 #include <unistd.h>
 
@@ -43,7 +44,7 @@ static int test_attach(const struct test* t) {
 	// Fetch the PID of the test process
 	pid_t pid = getpid();
 
-	printf("This process's PID: %d\n", pid);
+	LOG("This process's PID: %d\n", pid);
 
 	ASSERT_SUCCESS(
 		pakfire_cgroup_create(t->pakfire, "pakfire/test")
@@ -76,9 +77,65 @@ static int test_attach(const struct test* t) {
 	return EXIT_SUCCESS;
 }
 
+static void handle_signal(int signum) {
+	pid_t pid = getpid();
+
+	LOG("Process %d received signal %d\n", pid, signum);
+}
+
+static int child_process() {
+	LOG("Child process started with PID %d\n", getpid());
+
+	signal(SIGTERM, handle_signal);
+
+	// Do nothing
+	while (1) {
+		sleep(1);
+
+		LOG("Child process is still alive\n");
+	}
+
+	return 0;
+}
+
+static pid_t fork_child_process() {
+	pid_t pid = fork();
+	ASSERT(pid >= 0);
+
+	// Jump into child function
+	if (pid == 0)
+		return child_process();
+
+	return pid;
+}
+
+static int test_killall(const struct test* t) {
+	ASSERT_SUCCESS(
+		pakfire_cgroup_create(t->pakfire, "pakfire/test")
+	);
+
+	// Launch a background we can kill :)
+	pid_t pid = fork_child_process();
+
+	// Attach child to cgroup
+	ASSERT_SUCCESS(
+		pakfire_cgroup_attach(t->pakfire, "pakfire/test", pid)
+	);
+
+	// Kill everything
+	ASSERT_SUCCESS(
+		pakfire_cgroup_killall(t->pakfire, "pakfire/test")
+	);
+
+	ASSERT_SUCCESS(
+		pakfire_cgroup_destroy(t->pakfire, "pakfire/test")
+	);
+}
+
 int main(int argc, char** argv) {
 	testsuite_add_test(test_create_and_destroy);
 	testsuite_add_test(test_attach);
+	testsuite_add_test(test_killall);
 
 	return testsuite_run();
 }