#include "container.h"
#include "cgroup.h"

#define MEMORY "1073741824"
#define SHARES "256"
#define PIDS   "64"
#define WEIGHT "10"

struct cgrp_control {
	char control[256];
	struct cgrp_setting {
		char name[256];
		char value[256];
	} **settings;
};

static struct cgrp_setting add_to_tasks = {
	.name = "tasks",
	.value = "0"
};

static struct cgrp_control *cgrps[] = {
	& (struct cgrp_control) {
		.control = "memory",
		.settings = (struct cgrp_setting *[]) {
			& (struct cgrp_setting) {
				.name = "memory.limit_in_bytes",
				.value = MEMORY
			},
			& (struct cgrp_setting) {
				.name = "memory.kmem.limit_in_bytes",
				.value = MEMORY
			},
			&add_to_tasks,
			NULL
		}
	},
	& (struct cgrp_control) {
		.control = "cpu",
		.settings = (struct cgrp_setting *[]) {
			& (struct cgrp_setting) {
				.name = "cpu.shares",
				.value = SHARES
			},
			&add_to_tasks,
			NULL
		}
	},
	& (struct cgrp_control) {
		.control = "pids",
		.settings = (struct cgrp_setting *[]) {
			& (struct cgrp_setting) {
				.name = "pids.max",
				.value = PIDS
			},
			&add_to_tasks,
			NULL
		}
	},
	NULL
};

int resources(struct child_config *config)
{
	fprintf(stderr, "=> setting cgroups...");
	for (struct cgrp_control **cgrp = cgrps; *cgrp; cgrp++) {
		char dir[PATH_MAX] = {0};
		fprintf(stderr, "%s...", (*cgrp)->control);
		if (snprintf(dir, sizeof(dir), "/sys/fs/cgroup/%s/%s",
			     (*cgrp)->control, config->hostname) == -1) {
			return -1;
		}
		if (mkdir(dir, S_IRUSR | S_IWUSR | S_IXUSR)) {
			fprintf(stderr, "mkdir %s failed: %m\n", dir);
			return -1;
		}
		for (struct cgrp_setting **setting = (*cgrp)->settings; *setting; setting++) {
			char path[PATH_MAX] = {0};
			int fd = 0;
			if (snprintf(path, sizeof(path), "%s/%s", dir,
				     (*setting)->name) == -1) {
				fprintf(stderr, "snprintf failed: %m\n");
				return -1;
			}
			if ((fd = open(path, O_WRONLY)) == -1) {
				fprintf(stderr, "opening %s failed: %m\n", path);
				return -1;
			}
			if (write(fd, (*setting)->value, strlen((*setting)->value)) == -1) {
				fprintf(stderr, "writing to %s failed: %m\n", path);
				close(fd);
				return -1;
			}
			close(fd);
		}
	}
	fprintf(stderr, "done.\n");
	fprintf(stderr, "=> setting rlimit...");
	if (setrlimit(RLIMIT_NOFILE,
		      & (struct rlimit) {
			.rlim_max = FD_COUNT,
			.rlim_cur = FD_COUNT,
		})) {
		fprintf(stderr, "failed: %m\n");
		return 1;
	}
	fprintf(stderr, "done.\n");
	return 0;
}

int free_resources(struct child_config *config)
{
	fprintf(stderr, "=> cleaning cgroups...");
	for (struct cgrp_control **cgrp = cgrps; *cgrp; cgrp++) {
		char dir[PATH_MAX] = {0};
		char task[PATH_MAX] = {0};
		int task_fd = 0;
		if (snprintf(dir, sizeof(dir), "/sys/fs/cgroup/%s/%s",
			     (*cgrp)->control, config->hostname) == -1
		    || snprintf(task, sizeof(task), "/sys/fs/cgroup/%s/tasks",
				(*cgrp)->control) == -1) {
			fprintf(stderr, "snprintf failed: %m\n");
			return -1;
		}
		if ((task_fd = open(task, O_WRONLY)) == -1) {
			fprintf(stderr, "opening %s failed: %m\n", task);
			return -1;
		}
		if (write(task_fd, "0", 2) == -1) {
			fprintf(stderr, "writing to %s failed: %m\n", task);
			close(task_fd);
			return -1;
		}
		close(task_fd);
		if (rmdir(dir)) {
			fprintf(stderr, "rmdir %s failed: %m", dir);
			return -1;
		}
	}
	fprintf(stderr, "done.\n");
	return 0;
}