/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2020 Intel Corporation
 */

#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#ifndef RTE_EXEC_ENV_WINDOWS
#include <unistd.h>
#include <pthread.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#endif /* !RTE_EXEC_ENV_WINDOWS */

/* we won't link against libbsd, so just always use DPDKs-specific strlcpy */
#undef RTE_USE_LIBBSD
#include <rte_string_fns.h>
#include <rte_common.h>
#include <rte_spinlock.h>
#include <rte_log.h>

#include "rte_telemetry.h"
#include "telemetry_json.h"
#include "telemetry_data.h"
#include "telemetry_internal.h"

#define MAX_CMD_LEN 56
#define MAX_OUTPUT_LEN (1024 * 16)
#define MAX_CONNECTIONS 10

#ifndef RTE_EXEC_ENV_WINDOWS
static void *
client_handler(void *socket);
#endif /* !RTE_EXEC_ENV_WINDOWS */

struct cmd_callback {
	char cmd[MAX_CMD_LEN];
	telemetry_cb fn;
	telemetry_arg_cb fn_arg;
	void *arg;
	char help[RTE_TEL_MAX_STRING_LEN];
};

#ifndef RTE_EXEC_ENV_WINDOWS
struct socket {
	int sock;
	char path[sizeof(((struct sockaddr_un *)0)->sun_path)];
	handler fn;
	RTE_ATOMIC(uint16_t) *num_clients;
};
static struct socket v2_socket; /* socket for v2 telemetry */
static struct socket v1_socket; /* socket for v1 telemetry */
#endif /* !RTE_EXEC_ENV_WINDOWS */

static const char *telemetry_version; /* save rte_version */
static const char *socket_dir;        /* runtime directory */
static rte_cpuset_t *thread_cpuset;

RTE_LOG_REGISTER_DEFAULT(logtype, WARNING);
#define RTE_LOGTYPE_TELEMETRY logtype
#define TMTY_LOG_LINE(l, ...) RTE_LOG_LINE(l, TELEMETRY, "" __VA_ARGS__)

/* list of command callbacks, with one command registered by default */
static struct cmd_callback *callbacks;
static int num_callbacks; /* How many commands are registered */
/* Used when accessing or modifying list of command callbacks */
static rte_spinlock_t callback_sl = RTE_SPINLOCK_INITIALIZER;
#ifndef RTE_EXEC_ENV_WINDOWS
static RTE_ATOMIC(uint16_t) v2_clients;
#endif /* !RTE_EXEC_ENV_WINDOWS */

static int
register_cmd(const char *cmd, const char *help,
	     telemetry_cb fn, telemetry_arg_cb fn_arg, void *arg)
{
	struct cmd_callback *new_callbacks;
	const char *cmdp = cmd;
	int i = 0;

	if (strlen(cmd) >= MAX_CMD_LEN || (fn == NULL && fn_arg == NULL) || cmd[0] != '/'
			|| strlen(help) >= RTE_TEL_MAX_STRING_LEN)
		return -EINVAL;

	while (*cmdp != '\0') {
		if (!isalnum(*cmdp) && *cmdp != '_' && *cmdp != '/')
			return -EINVAL;
		cmdp++;
	}

	rte_spinlock_lock(&callback_sl);
	new_callbacks = realloc(callbacks, sizeof(callbacks[0]) * (num_callbacks + 1));
	if (new_callbacks == NULL) {
		rte_spinlock_unlock(&callback_sl);
		return -ENOMEM;
	}
	callbacks = new_callbacks;

	while (i < num_callbacks && strcmp(cmd, callbacks[i].cmd) > 0)
		i++;
	if (i != num_callbacks)
		/* Move elements to keep the list alphabetical */
		memmove(callbacks + i + 1, callbacks + i,
			sizeof(struct cmd_callback) * (num_callbacks - i));

	strlcpy(callbacks[i].cmd, cmd, MAX_CMD_LEN);
	callbacks[i].fn = fn;
	callbacks[i].fn_arg = fn_arg;
	callbacks[i].arg = arg;
	strlcpy(callbacks[i].help, help, RTE_TEL_MAX_STRING_LEN);
	num_callbacks++;
	rte_spinlock_unlock(&callback_sl);

	return 0;
}

int
rte_telemetry_register_cmd(const char *cmd, telemetry_cb fn, const char *help)
{
	return register_cmd(cmd, help, fn, NULL, NULL);
}

int
rte_telemetry_register_cmd_arg(const char *cmd, telemetry_arg_cb fn, void *arg, const char *help)
{
	return register_cmd(cmd, help, NULL, fn, arg);
}

#ifndef RTE_EXEC_ENV_WINDOWS

static int
list_commands(const char *cmd __rte_unused, const char *params __rte_unused,
		struct rte_tel_data *d)
{
	int i;

	rte_tel_data_start_array(d, RTE_TEL_STRING_VAL);
	rte_spinlock_lock(&callback_sl);
	for (i = 0; i < num_callbacks; i++)
		rte_tel_data_add_array_string(d, callbacks[i].cmd);
	rte_spinlock_unlock(&callback_sl);
	return 0;
}

static int
json_info(const char *cmd __rte_unused, const char *params __rte_unused,
		struct rte_tel_data *d)
{
	rte_tel_data_start_dict(d);
	rte_tel_data_add_dict_string(d, "version", telemetry_version);
	rte_tel_data_add_dict_int(d, "pid", getpid());
	rte_tel_data_add_dict_int(d, "max_output_len", MAX_OUTPUT_LEN);
	return 0;
}

static int
command_help(const char *cmd __rte_unused, const char *params,
		struct rte_tel_data *d)
{
	int i;
	/* if no parameters return our own help text */
	const char *to_lookup = (params == NULL ? cmd : params);

	rte_tel_data_start_dict(d);
	rte_spinlock_lock(&callback_sl);
	for (i = 0; i < num_callbacks; i++)
		if (strcmp(to_lookup, callbacks[i].cmd) == 0) {
			if (params == NULL)
				rte_tel_data_string(d, callbacks[i].help);
			else
				rte_tel_data_add_dict_string(d, params,	callbacks[i].help);
			break;
		}
	rte_spinlock_unlock(&callback_sl);
	if (i == num_callbacks)
		return -1;
	return 0;
}

static int
container_to_json(const struct rte_tel_data *d, char *out_buf, size_t buf_len)
{
	size_t used = 0;
	unsigned int i;

	if (d->type != TEL_DICT && d->type != TEL_ARRAY_UINT &&
		d->type != TEL_ARRAY_INT && d->type != TEL_ARRAY_STRING)
		return snprintf(out_buf, buf_len, "null");

	if (d->type == TEL_DICT)
		used = rte_tel_json_empty_obj(out_buf, buf_len, 0);
	else
		used = rte_tel_json_empty_array(out_buf, buf_len, 0);

	if (d->type == TEL_ARRAY_UINT)
		for (i = 0; i < d->data_len; i++)
			used = rte_tel_json_add_array_uint(out_buf,
				buf_len, used,
				d->data.array[i].uval);
	if (d->type == TEL_ARRAY_INT)
		for (i = 0; i < d->data_len; i++)
			used = rte_tel_json_add_array_int(out_buf,
				buf_len, used,
				d->data.array[i].ival);
	if (d->type == TEL_ARRAY_STRING)
		for (i = 0; i < d->data_len; i++)
			used = rte_tel_json_add_array_string(out_buf,
				buf_len, used,
				d->data.array[i].sval);
	if (d->type == TEL_DICT)
		for (i = 0; i < d->data_len; i++) {
			const struct tel_dict_entry *v = &d->data.dict[i];
			switch (v->type) {
			case RTE_TEL_STRING_VAL:
				used = rte_tel_json_add_obj_str(out_buf,
						buf_len, used,
						v->name, v->value.sval);
				break;
			case RTE_TEL_INT_VAL:
				used = rte_tel_json_add_obj_int(out_buf,
						buf_len, used,
						v->name, v->value.ival);
				break;
			case RTE_TEL_UINT_VAL:
				used = rte_tel_json_add_obj_uint(out_buf,
						buf_len, used,
						v->name, v->value.uval);
				break;
			case RTE_TEL_CONTAINER:
			{
				char *temp = malloc(buf_len);
				if (temp == NULL)
					break;
				*temp = '\0';  /* ensure valid string */

				const struct container *cont =
						&v->value.container;
				if (container_to_json(cont->data,
						temp, buf_len) != 0)
					used = rte_tel_json_add_obj_json(
							out_buf,
							buf_len, used,
							v->name, temp);
				if (!cont->keep)
					rte_tel_data_free(cont->data);
				free(temp);
				break;
			}
			}
		}

	return used;
}

static void
output_json(const char *cmd, const struct rte_tel_data *d, int s)
{
	char out_buf[MAX_OUTPUT_LEN];

	char *cb_data_buf;
	size_t buf_len, prefix_used, used = 0;
	unsigned int i;

	RTE_BUILD_BUG_ON(sizeof(out_buf) < MAX_CMD_LEN +
			RTE_TEL_MAX_SINGLE_STRING_LEN + 10);

	prefix_used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":",
			MAX_CMD_LEN, cmd);
	cb_data_buf = &out_buf[prefix_used];
	buf_len = sizeof(out_buf) - prefix_used - 1; /* space for '}' */

	switch (d->type) {
	case TEL_NULL:
		used = strlcpy(cb_data_buf, "null", buf_len);
		break;

	case TEL_STRING:
		used = rte_tel_json_str(cb_data_buf, buf_len, 0, d->data.str);
		break;

	case TEL_DICT:
		used = rte_tel_json_empty_obj(cb_data_buf, buf_len, 0);
		for (i = 0; i < d->data_len; i++) {
			const struct tel_dict_entry *v = &d->data.dict[i];
			switch (v->type) {
			case RTE_TEL_STRING_VAL:
				used = rte_tel_json_add_obj_str(cb_data_buf,
						buf_len, used,
						v->name, v->value.sval);
				break;
			case RTE_TEL_INT_VAL:
				used = rte_tel_json_add_obj_int(cb_data_buf,
						buf_len, used,
						v->name, v->value.ival);
				break;
			case RTE_TEL_UINT_VAL:
				used = rte_tel_json_add_obj_uint(cb_data_buf,
						buf_len, used,
						v->name, v->value.uval);
				break;
			case RTE_TEL_CONTAINER:
			{
				char *temp = malloc(buf_len);
				if (temp == NULL)
					break;
				*temp = '\0';  /* ensure valid string */

				const struct container *cont =
						&v->value.container;
				if (container_to_json(cont->data,
						temp, buf_len) != 0)
					used = rte_tel_json_add_obj_json(
							cb_data_buf,
							buf_len, used,
							v->name, temp);
				if (!cont->keep)
					rte_tel_data_free(cont->data);
				free(temp);
			}
			}
		}
		break;

	case TEL_ARRAY_STRING:
	case TEL_ARRAY_INT:
	case TEL_ARRAY_UINT:
	case TEL_ARRAY_CONTAINER:
		used = rte_tel_json_empty_array(cb_data_buf, buf_len, 0);
		for (i = 0; i < d->data_len; i++)
			if (d->type == TEL_ARRAY_STRING)
				used = rte_tel_json_add_array_string(
						cb_data_buf,
						buf_len, used,
						d->data.array[i].sval);
			else if (d->type == TEL_ARRAY_INT)
				used = rte_tel_json_add_array_int(cb_data_buf,
						buf_len, used,
						d->data.array[i].ival);
			else if (d->type == TEL_ARRAY_UINT)
				used = rte_tel_json_add_array_uint(cb_data_buf,
						buf_len, used,
						d->data.array[i].uval);
			else if (d->type == TEL_ARRAY_CONTAINER) {
				char *temp = malloc(buf_len);
				if (temp == NULL)
					break;
				*temp = '\0';  /* ensure valid string */

				const struct container *rec_data =
						&d->data.array[i].container;
				if (container_to_json(rec_data->data,
						temp, buf_len) != 0)
					used = rte_tel_json_add_array_json(
							cb_data_buf,
							buf_len, used, temp);
				if (!rec_data->keep)
					rte_tel_data_free(rec_data->data);
				free(temp);
			}
		break;
	}
	used += prefix_used;
	used += strlcat(out_buf + used, "}", sizeof(out_buf) - used);
	if (write(s, out_buf, used) < 0)
		perror("Error writing to socket");
}

static void
perform_command(const struct cmd_callback *cb, const char *cmd, const char *param, int s)
{
	struct rte_tel_data data = {0};
	int ret;

	if (cb->fn_arg != NULL)
		ret = cb->fn_arg(cmd, param, cb->arg, &data);
	else
		ret = cb->fn(cmd, param, &data);

	if (ret < 0) {
		char out_buf[MAX_CMD_LEN + 10];
		int used = snprintf(out_buf, sizeof(out_buf), "{\"%.*s\":null}",
				MAX_CMD_LEN, cmd ? cmd : "none");
		if (write(s, out_buf, used) < 0)
			perror("Error writing to socket");
		return;
	}
	output_json(cmd, &data, s);
}

static int
unknown_command(const char *cmd __rte_unused, const char *params __rte_unused,
		struct rte_tel_data *d)
{
	return d->type = TEL_NULL;
}

static void *
client_handler(void *sock_id)
{
	int s = (int)(uintptr_t)sock_id;
	char buffer[1024];
	char info_str[1024];
	snprintf(info_str, sizeof(info_str),
			"{\"version\":\"%s\",\"pid\":%d,\"max_output_len\":%d}",
			telemetry_version, getpid(), MAX_OUTPUT_LEN);
	if (write(s, info_str, strlen(info_str)) < 0) {
		TMTY_LOG_LINE(DEBUG, "Socket write base info to client failed");
		goto exit;
	}

	/* receive data is not null terminated */
	int bytes = read(s, buffer, sizeof(buffer) - 1);
	while (bytes > 0) {
		buffer[bytes] = 0;
		const char *cmd = strtok(buffer, ",");
		const char *param = strtok(NULL, "\0");
		struct cmd_callback cb = {.fn = unknown_command};
		int i;

		if (cmd && strlen(cmd) < MAX_CMD_LEN) {
			rte_spinlock_lock(&callback_sl);
			for (i = 0; i < num_callbacks; i++)
				if (strcmp(cmd, callbacks[i].cmd) == 0) {
					cb = callbacks[i];
					break;
				}
			rte_spinlock_unlock(&callback_sl);
		}
		perform_command(&cb, cmd, param, s);

		bytes = read(s, buffer, sizeof(buffer) - 1);
	}
exit:
	close(s);
	rte_atomic_fetch_sub_explicit(&v2_clients, 1, rte_memory_order_relaxed);
	return NULL;
}

static void *
socket_listener(void *socket)
{
	while (1) {
		pthread_t th;
		int rc;
		struct socket *s = (struct socket *)socket;
		int s_accepted = accept(s->sock, NULL, NULL);
		if (s_accepted < 0) {
			TMTY_LOG_LINE(ERR, "Error with accept, telemetry thread quitting");
			return NULL;
		}
		if (s->num_clients != NULL) {
			uint16_t conns = rte_atomic_load_explicit(s->num_clients,
					rte_memory_order_relaxed);
			if (conns >= MAX_CONNECTIONS) {
				close(s_accepted);
				continue;
			}
			rte_atomic_fetch_add_explicit(s->num_clients, 1,
					rte_memory_order_relaxed);
		}
		rc = pthread_create(&th, NULL, s->fn,
				    (void *)(uintptr_t)s_accepted);
		if (rc != 0) {
			TMTY_LOG_LINE(ERR, "Error with create client thread: %s",
				 strerror(rc));
			close(s_accepted);
			if (s->num_clients != NULL)
				rte_atomic_fetch_sub_explicit(s->num_clients, 1,
						   rte_memory_order_relaxed);
			continue;
		}
		pthread_detach(th);
	}
	return NULL;
}

static inline char *
get_socket_path(const char *runtime_dir, const int version)
{
	static char path[PATH_MAX];
	snprintf(path, sizeof(path), "%s/dpdk_telemetry.v%d",
			strlen(runtime_dir) ? runtime_dir : "/tmp", version);
	return path;
}

static void
unlink_sockets(void)
{
	if (v2_socket.path[0])
		unlink(v2_socket.path);
	if (v1_socket.path[0])
		unlink(v1_socket.path);
}

static int
create_socket(char *path)
{
	int sock = socket(AF_UNIX, SOCK_SEQPACKET, 0);
	if (sock < 0) {
		TMTY_LOG_LINE(ERR, "Error with socket creation, %s", strerror(errno));
		return -1;
	}

	struct sockaddr_un sun = {.sun_family = AF_UNIX};
	strlcpy(sun.sun_path, path, sizeof(sun.sun_path));
	TMTY_LOG_LINE(DEBUG, "Attempting socket bind to path '%s'", path);

	if (bind(sock, (void *) &sun, sizeof(sun)) < 0) {
		struct stat st;

		TMTY_LOG_LINE(DEBUG, "Initial bind to socket '%s' failed.", path);

		/* first check if we have a runtime dir */
		if (stat(socket_dir, &st) < 0 || !S_ISDIR(st.st_mode)) {
			TMTY_LOG_LINE(ERR, "Cannot access DPDK runtime directory: %s", socket_dir);
			close(sock);
			return -ENOENT;
		}

		/* check if current socket is active */
		if (connect(sock, (void *)&sun, sizeof(sun)) == 0) {
			close(sock);
			return -EADDRINUSE;
		}

		/* socket is not active, delete and attempt rebind */
		TMTY_LOG_LINE(DEBUG, "Attempting unlink and retrying bind");
		unlink(sun.sun_path);
		if (bind(sock, (void *) &sun, sizeof(sun)) < 0) {
			TMTY_LOG_LINE(ERR, "Error binding socket: %s", strerror(errno));
			close(sock);
			return -errno; /* if unlink failed, this will be -EADDRINUSE as above */
		}
	}

	if (listen(sock, 1) < 0) {
		TMTY_LOG_LINE(ERR, "Error calling listen for socket: %s", strerror(errno));
		unlink(sun.sun_path);
		close(sock);
		return -errno;
	}
	TMTY_LOG_LINE(DEBUG, "Socket creation and binding ok");

	return sock;
}

static void
set_thread_name(pthread_t id __rte_unused, const char *name __rte_unused)
{
#if defined RTE_EXEC_ENV_LINUX && defined __GLIBC__ && defined __GLIBC_PREREQ
#if __GLIBC_PREREQ(2, 12)
	pthread_setname_np(id, name);
#endif
#elif defined RTE_EXEC_ENV_FREEBSD
	pthread_set_name_np(id, name);
#endif
}

static int
telemetry_legacy_init(void)
{
	pthread_t t_old;
	int rc;

	if (num_legacy_callbacks == 1) {
		TMTY_LOG_LINE(DEBUG, "No legacy callbacks, legacy socket not created");
		return -1;
	}

	v1_socket.fn = legacy_client_handler;
	if ((size_t) snprintf(v1_socket.path, sizeof(v1_socket.path),
			"%s/telemetry", socket_dir) >= sizeof(v1_socket.path)) {
		TMTY_LOG_LINE(ERR, "Error with socket binding, path too long");
		return -1;
	}
	v1_socket.sock = create_socket(v1_socket.path);
	if (v1_socket.sock < 0) {
		v1_socket.path[0] = '\0';
		return -1;
	}
	rc = pthread_create(&t_old, NULL, socket_listener, &v1_socket);
	if (rc != 0) {
		TMTY_LOG_LINE(ERR, "Error with create legacy socket thread: %s",
			 strerror(rc));
		close(v1_socket.sock);
		v1_socket.sock = -1;
		unlink(v1_socket.path);
		v1_socket.path[0] = '\0';
		return -1;
	}
	pthread_setaffinity_np(t_old, sizeof(*thread_cpuset), thread_cpuset);
	set_thread_name(t_old, "dpdk-telemet-v1");
	TMTY_LOG_LINE(DEBUG, "Legacy telemetry socket initialized ok");
	pthread_detach(t_old);
	return 0;
}

static int
telemetry_v2_init(void)
{
	char spath[sizeof(v2_socket.path)];
	pthread_t t_new;
	short suffix = 0;
	int rc;

	v2_socket.num_clients = &v2_clients;
	rte_telemetry_register_cmd("/", list_commands,
			"Returns list of available commands, Takes no parameters");
	rte_telemetry_register_cmd("/info", json_info,
			"Returns DPDK Telemetry information. Takes no parameters");
	rte_telemetry_register_cmd("/help", command_help,
			"Returns help text for a command. Parameters: string command");
	v2_socket.fn = client_handler;
	if (strlcpy(spath, get_socket_path(socket_dir, 2), sizeof(spath)) >= sizeof(spath)) {
		TMTY_LOG_LINE(ERR, "Error with socket binding, path too long");
		return -1;
	}
	memcpy(v2_socket.path, spath, sizeof(v2_socket.path));

	v2_socket.sock = create_socket(v2_socket.path);
	while (v2_socket.sock < 0) {
		/* bail out on unexpected error, or suffix wrap-around */
		if (v2_socket.sock != -EADDRINUSE || suffix < 0) {
			v2_socket.path[0] = '\0'; /* clear socket path */
			return -1;
		}
		/* add a suffix to the path if the basic version fails */
		if (snprintf(v2_socket.path, sizeof(v2_socket.path), "%s:%d",
				spath, ++suffix) >= (int)sizeof(v2_socket.path)) {
			TMTY_LOG_LINE(ERR, "Error with socket binding, path too long");
			return -1;
		}
		v2_socket.sock = create_socket(v2_socket.path);
	}
	rc = pthread_create(&t_new, NULL, socket_listener, &v2_socket);
	if (rc != 0) {
		TMTY_LOG_LINE(ERR, "Error with create socket thread: %s",
			 strerror(rc));
		close(v2_socket.sock);
		v2_socket.sock = -1;
		unlink(v2_socket.path);
		v2_socket.path[0] = '\0';
		return -1;
	}
	pthread_setaffinity_np(t_new, sizeof(*thread_cpuset), thread_cpuset);
	set_thread_name(t_new, "dpdk-telemet-v2");
	pthread_detach(t_new);
	atexit(unlink_sockets);

	return 0;
}

#endif /* !RTE_EXEC_ENV_WINDOWS */

int32_t
rte_telemetry_init(const char *runtime_dir, const char *rte_version, rte_cpuset_t *cpuset)
{
	telemetry_version = rte_version;
	socket_dir = runtime_dir;
	thread_cpuset = cpuset;

#ifndef RTE_EXEC_ENV_WINDOWS
	if (telemetry_v2_init() != 0)
		return -1;
	TMTY_LOG_LINE(DEBUG, "Telemetry initialized ok");
	telemetry_legacy_init();
#endif /* RTE_EXEC_ENV_WINDOWS */

	return 0;
}