support configure sysctl for container

{
	"id": "test-container-sysctl",
	"containers" : [{
	    "name": "ubuntu",
	    "image": "ubuntu:latest",
	    "workdir": "/",
	    "command": ["/bin/bash"],
	    "sysctl":{"net.ipv4.ip_forward": "1", "net.core.somaxconn": "256"}
	}],
	"resource": {
	    "vcpu": 1,
	    "memory": 512
	},
	"tty": true
}

Signed-off-by: Gao feng <omarapazanadi@gmail.com>

src/container.c

@@ -167,6 +167,45 @@ static int container_setup_mount(struct hyper_container *container)
 	return 0;
 }
 
+static int container_setup_sysctl(struct hyper_container *container)
+{
+	int i, size, len, l, fd;
+	struct sysctl *sys;
+
+	for (i = 0; i < container->sys_num; i++) {
+		char path[256];
+
+		len = 0;
+		sys = &container->sys[i];
+		size = strlen(sys->value);
+
+		sprintf(path, "/proc/sys/%s", sys->path);
+		fprintf(stdout, "sysctl %s value %s\n", sys->path, sys->value);
+
+		fd = open(path, O_WRONLY);
+		if (fd < 0) {
+			perror("open file failed");
+			goto out;
+		}
+
+		while (len < size) {
+			l = write(fd, sys->value + len, size - len);
+			if (l < 0) {
+				perror("fail to write sysctl");
+				close(fd);
+				goto out;
+			}
+			len += l;
+		}
+
+		close(fd);
+	}
+
+	return 0;
+out:
+	return -1;
+}
+
 static int container_setup_dns(struct hyper_container *container)
 {
 	int fd;
@@ -366,7 +405,12 @@ static int hyper_container_init(void *data)
 	}
 
 	if (container_setup_mount(container) < 0) {
-		fprintf(stderr, "container sets up mount ns failed\n");
+		fprintf(stderr, "container sets up mount failed\n");
+		goto fail;
+	}
+
+	if (container_setup_sysctl(container) < 0) {
+		fprintf(stderr, "container sets up sysctl failed\n");
 		goto fail;
 	}
 
@@ -535,6 +579,7 @@ void hyper_cleanup_container(struct hyper_pod *pod)
 	struct volume *vol;
 	struct env *env;
 	struct fsmap *map;
+	struct sysctl *sys;
 	char root[512];
 
 	for (i = 0; i < pod->c_num; i++) {
@@ -565,6 +610,13 @@ void hyper_cleanup_container(struct hyper_pod *pod)
 		}
 		free(c->envs);
 
+		for (j = 0; j < c->sys_num; j++) {
+			sys = &(c->sys[j]);
+			free(sys->path);
+			free(sys->value);
+		}
+		free(c->sys);
+
 		for (j = 0; j < c->maps_num; j++) {
 			map = &(c->maps[j]);
 			free(map->source);

src/container.h

@@ -21,6 +21,11 @@ struct fsmap {
 	int	readonly;
 };
 
+struct sysctl {
+	char	*path;
+	char	*value;
+};
+
 struct hyper_container {
 	char			*id;
 	char			*rootfs;
@@ -30,9 +35,11 @@ struct hyper_container {
 	struct volume		*vols;
 	struct env		*envs;
 	struct fsmap		*maps;
+	struct sysctl		*sys;
 	int			vols_num;
 	int			envs_num;
 	int			maps_num;
+	int			sys_num;
 	int			ns;
 	uint32_t		code;
 	struct hyper_exec	exec;

src/parse.c

@@ -186,6 +186,32 @@ static int container_parse_envs(struct hyper_container *c, char *json, jsmntok_t
 	return i;
 }
 
+static int container_parse_sysctl(struct hyper_container *c, char *json, jsmntok_t *toks)
+{
+	int i = 1, j;
+	char *p;
+
+	if (toks[i].type != JSMN_OBJECT) {
+		fprintf(stdout, "sysctl need object\n");
+		return -1;
+	}
+
+	c->sys_num = toks[i].size;
+	fprintf(stdout, "sysctl size %d\n", c->sys_num);
+	c->sys = calloc(c->sys_num, sizeof(*c->sys));
+
+	for (j = 0; j < c->sys_num; j++) {
+		c->sys[j].path = strdup(json_token_str(json, &toks[++i]));
+		while((p = strchr(c->sys[j].path, '.')) != NULL) {
+			*p = '/';
+		}
+		c->sys[j].value = strdup(json_token_str(json, &toks[++i]));
+		fprintf(stdout, "sysctl %s:%s\n", c->sys[j].path, c->sys[j].value);
+	}
+	return i;
+}
+
+
 static int hyper_parse_container(struct hyper_pod *pod, struct hyper_container *c,
 			       char *json, jsmntok_t *toks)
 {
@@ -259,6 +285,11 @@ static int hyper_parse_container(struct hyper_pod *pod, struct hyper_container *
 			if (next < 0)
 				return -1;
 			i += next;
+		} else if (json_token_streq(json, t, "sysctl") && t->size == 1) {
+			next = container_parse_sysctl(c, json, &toks[i]);
+			if (next < 0)
+				return -1;
+			i += next;
 		} else if (json_token_streq(json, t, "restartPolicy") && t->size == 1) {
 			i++;
 /*