/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright 2017 6WIND S.A.
 * Copyright 2017 Mellanox Technologies, Ltd
 */

#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>

#include <rte_debug.h>
#include <rte_devargs.h>
#include <rte_malloc.h>
#include <rte_kvargs.h>
#include <rte_string_fns.h>

#include "failsafe_private.h"

/* Callback used when a new device is found in devargs */
typedef int (parse_cb)(struct rte_eth_dev *dev, const char *params,
		uint8_t head);

uint64_t failsafe_hotplug_poll = FAILSAFE_HOTPLUG_DEFAULT_TIMEOUT_MS;
int failsafe_mac_from_arg;

static const char * const pmd_failsafe_init_parameters[] = {
	PMD_FAILSAFE_HOTPLUG_POLL_KVARG,
	PMD_FAILSAFE_MAC_KVARG,
	NULL,
};

/*
 * input: text.
 * output: 0: if text[0] != '(',
 *         0: if there are no corresponding ')'
 *         n: distance to corresponding ')' otherwise
 */
static size_t
closing_paren(const char *text)
{
	int nb_open = 0;
	size_t i = 0;

	while (text[i] != '\0') {
		if (text[i] == '(')
			nb_open++;
		if (text[i] == ')')
			nb_open--;
		if (nb_open == 0)
			return i;
		i++;
	}
	return 0;
}

static int
fs_parse_device(struct sub_device *sdev, char *args)
{
	struct rte_devargs *d;
	int ret;

	d = &sdev->devargs;
	DEBUG("%s", args);
	ret = rte_devargs_parse(d, args);
	if (ret) {
		DEBUG("devargs parsing failed with code %d", ret);
		return ret;
	}
	sdev->bus = d->bus;
	sdev->state = DEV_PARSED;
	return 0;
}

static void
fs_sanitize_cmdline(char *args)
{
	char *nl;

	nl = strrchr(args, '\n');
	if (nl)
		nl[0] = '\0';
}

static int
fs_execute_cmd(struct sub_device *sdev, char *cmdline)
{
	FILE *fp;
	/* store possible newline as well */
	char output[DEVARGS_MAXLEN + 1];
	size_t len;
	int ret;

	RTE_ASSERT(cmdline != NULL || sdev->cmdline != NULL);
	if (sdev->cmdline == NULL) {
		size_t i;

		len = strlen(cmdline) + 1;
		sdev->cmdline = calloc(1, len);
		if (sdev->cmdline == NULL) {
			ERROR("Command line allocation failed");
			return -ENOMEM;
		}
		strlcpy(sdev->cmdline, cmdline, len);
		/* Replace all commas in the command line by spaces */
		for (i = 0; i < len; i++)
			if (sdev->cmdline[i] == ',')
				sdev->cmdline[i] = ' ';
	}
	DEBUG("'%s'", sdev->cmdline);
	fp = popen(sdev->cmdline, "r");
	if (fp == NULL) {
		ret = -errno;
		ERROR("popen: %s", strerror(errno));
		return ret;
	}
	/* We only read one line */
	if (fgets(output, sizeof(output) - 1, fp) == NULL) {
		DEBUG("Could not read command output");
		ret = -ENODEV;
		goto ret_pclose;
	}
	fs_sanitize_cmdline(output);
	if (output[0] == '\0') {
		ret = -ENODEV;
		goto ret_pclose;
	}
	ret = fs_parse_device(sdev, output);
	if (ret)
		ERROR("Parsing device '%s' failed", output);
ret_pclose:
	if (pclose(fp) == -1)
		ERROR("pclose: %s", strerror(errno));
	return ret;
}

static int
fs_read_fd(struct sub_device *sdev, char *fd_str)
{
	FILE *fp = NULL;
	int fd = -1;
	/* store possible newline as well */
	char output[DEVARGS_MAXLEN + 1];
	int err = -ENODEV;
	int oflags;
	int lcount;

	RTE_ASSERT(fd_str != NULL || sdev->fd_str != NULL);
	if (sdev->fd_str == NULL) {
		sdev->fd_str = strdup(fd_str);
		if (sdev->fd_str == NULL) {
			ERROR("Command line allocation failed");
			return -ENOMEM;
		}
	}
	errno = 0;
	fd = strtol(fd_str, &fd_str, 0);
	if (errno || *fd_str || fd < 0) {
		ERROR("Parsing FD number failed");
		goto error;
	}
	/* Fiddle with copy of file descriptor */
	fd = dup(fd);
	if (fd == -1)
		goto error;
	oflags = fcntl(fd, F_GETFL);
	if (oflags == -1)
		goto error;
	if (fcntl(fd, F_SETFL, oflags | O_NONBLOCK) == -1)
		goto error;
	fp = fdopen(fd, "r");
	if (fp == NULL)
		goto error;
	fd = -1;
	/* Only take the last line into account */
	lcount = 0;
	while (fgets(output, sizeof(output), fp))
		++lcount;
	if (lcount == 0)
		goto error;
	else if (ferror(fp) && errno != EAGAIN)
		goto error;
	/* Line must end with a newline character */
	fs_sanitize_cmdline(output);
	if (output[0] == '\0')
		goto error;
	err = fs_parse_device(sdev, output);
	if (err)
		ERROR("Parsing device '%s' failed", output);
error:
	if (fp)
		fclose(fp);
	if (fd != -1)
		close(fd);
	return err;
}

static int
fs_parse_device_param(struct rte_eth_dev *dev, const char *param,
		uint8_t head)
{
	struct fs_priv *priv;
	struct sub_device *sdev;
	char *args = NULL;
	size_t a, b;
	int ret;

	priv = PRIV(dev);
	a = 0;
	b = 0;
	ret = 0;
	while  (param[b] != '(' &&
		param[b] != '\0')
		b++;
	a = b;
	b += closing_paren(&param[b]);
	if (a == b) {
		ERROR("Dangling parenthesis");
		return -EINVAL;
	}
	a += 1;
	args = strndup(&param[a], b - a);
	if (args == NULL) {
		ERROR("Not enough memory for parameter parsing");
		return -ENOMEM;
	}
	sdev = &priv->subs[head];
	if (strncmp(param, "dev", 3) == 0) {
		ret = fs_parse_device(sdev, args);
		if (ret)
			goto free_args;
	} else if (strncmp(param, "exec", 4) == 0) {
		ret = fs_execute_cmd(sdev, args);
		if (ret == -ENODEV) {
			DEBUG("Reading device info from command line failed");
			ret = 0;
		}
		if (ret)
			goto free_args;
	} else if (strncmp(param, "fd(", 3) == 0) {
		ret = fs_read_fd(sdev, args);
		if (ret == -ENODEV) {
			DEBUG("Reading device info from FD failed");
			ret = 0;
		}
		if (ret)
			goto free_args;
	} else {
		ERROR("Unrecognized device type: %.*s", (int)b, param);
		return -EINVAL;
	}
free_args:
	free(args);
	return ret;
}

static int
fs_parse_sub_devices(parse_cb *cb,
		struct rte_eth_dev *dev, const char *params)
{
	size_t a, b;
	uint8_t head;
	int ret;

	a = 0;
	head = 0;
	ret = 0;
	while (params[a] != '\0') {
		b = a;
		while (params[b] != '(' &&
		       params[b] != ',' &&
		       params[b] != '\0')
			b++;
		if (b == a) {
			ERROR("Invalid parameter");
			return -EINVAL;
		}
		if (params[b] == ',') {
			a = b + 1;
			continue;
		}
		if (params[b] == '(') {
			size_t start = b;

			b += closing_paren(&params[b]);
			if (b == start) {
				ERROR("Dangling parenthesis");
				return -EINVAL;
			}
			ret = (*cb)(dev, &params[a], head);
			if (ret)
				return ret;
			head += 1;
			b += 1;
			if (params[b] == '\0')
				return 0;
		}
		a = b + 1;
	}
	return 0;
}

static int
fs_remove_sub_devices_definition(char params[DEVARGS_MAXLEN])
{
	char buffer[DEVARGS_MAXLEN] = {0};
	size_t a, b;
	int i;

	a = 0;
	i = 0;
	while (params[a] != '\0') {
		b = a;
		while (params[b] != '(' &&
		       params[b] != ',' &&
		       params[b] != '\0')
			b++;
		if (b == a) {
			ERROR("Invalid parameter");
			return -EINVAL;
		}
		if (params[b] == ',' || params[b] == '\0') {
			size_t len = b - a;

			if (i > 0)
				len += 1;
			snprintf(&buffer[i], len + 1, "%s%s",
					i ? "," : "", &params[a]);
			i += len;
		} else if (params[b] == '(') {
			size_t start = b;

			b += closing_paren(&params[b]);
			if (b == start)
				return -EINVAL;
			b += 1;
			if (params[b] == '\0')
				goto out;
		}
		a = b + 1;
	}
out:
	strlcpy(params, buffer, DEVARGS_MAXLEN);
	return 0;
}

static int
fs_get_u64_arg(const char *key __rte_unused,
		const char *value, void *out)
{
	uint64_t *u64 = out;
	char *endptr = NULL;

	if ((value == NULL) || (out == NULL))
		return -EINVAL;
	errno = 0;
	*u64 = strtoull(value, &endptr, 0);
	if (errno != 0)
		return -errno;
	if (endptr == value)
		return -1;
	return 0;
}

static int
fs_get_mac_addr_arg(const char *key __rte_unused,
		const char *value, void *out)
{
	struct rte_ether_addr *ea = out;

	if ((value == NULL) || (out == NULL))
		return -EINVAL;

	return rte_ether_unformat_addr(value, ea);
}

int
failsafe_args_parse(struct rte_eth_dev *dev, const char *params)
{
	struct fs_priv *priv;
	char mut_params[DEVARGS_MAXLEN] = "";
	struct rte_kvargs *kvlist = NULL;
	unsigned int arg_count;
	size_t n;
	int ret;

	priv = PRIV(dev);
	ret = 0;
	priv->subs_tx = FAILSAFE_MAX_ETHPORTS;
	/* default parameters */
	n = strlcpy(mut_params, params, sizeof(mut_params));
	if (n >= sizeof(mut_params)) {
		ERROR("Parameter string too long (>=%zu)",
				sizeof(mut_params));
		return -ENOMEM;
	}
	ret = fs_parse_sub_devices(fs_parse_device_param,
				   dev, params);
	if (ret < 0)
		return ret;
	ret = fs_remove_sub_devices_definition(mut_params);
	if (ret < 0)
		return ret;
	if (strnlen(mut_params, sizeof(mut_params)) > 0) {
		kvlist = rte_kvargs_parse(mut_params,
				pmd_failsafe_init_parameters);
		if (kvlist == NULL) {
			ERROR("Error parsing parameters, usage:\n"
				PMD_FAILSAFE_PARAM_STRING);
			return -1;
		}
		/* PLUG_IN event poll timer */
		arg_count = rte_kvargs_count(kvlist,
				PMD_FAILSAFE_HOTPLUG_POLL_KVARG);
		if (arg_count == 1) {
			ret = rte_kvargs_process(kvlist,
					PMD_FAILSAFE_HOTPLUG_POLL_KVARG,
					&fs_get_u64_arg, &failsafe_hotplug_poll);
			if (ret < 0)
				goto free_kvlist;
		}
		/* MAC addr */
		arg_count = rte_kvargs_count(kvlist,
				PMD_FAILSAFE_MAC_KVARG);
		if (arg_count > 0) {
			ret = rte_kvargs_process(kvlist,
					PMD_FAILSAFE_MAC_KVARG,
					&fs_get_mac_addr_arg,
					&dev->data->mac_addrs[0]);
			if (ret < 0)
				goto free_kvlist;

			failsafe_mac_from_arg = 1;
		}
	}
	PRIV(dev)->state = DEV_PARSED;
free_kvlist:
	rte_kvargs_free(kvlist);
	return ret;
}

void
failsafe_args_free(struct rte_eth_dev *dev)
{
	struct sub_device *sdev;
	uint8_t i;

	FOREACH_SUBDEV(sdev, i, dev) {
		free(sdev->cmdline);
		sdev->cmdline = NULL;
		free(sdev->fd_str);
		sdev->fd_str = NULL;
		free(sdev->devargs.args);
		sdev->devargs.args = NULL;
	}
}

static int
fs_count_device(struct rte_eth_dev *dev, const char *param,
		uint8_t head __rte_unused)
{
	size_t b = 0;

	while  (param[b] != '(' &&
		param[b] != '\0')
		b++;
	if (strncmp(param, "dev", b) != 0 &&
	    strncmp(param, "exec", b) != 0 &&
	    strncmp(param, "fd(", b) != 0) {
		ERROR("Unrecognized device type: %.*s", (int)b, param);
		return -EINVAL;
	}
	PRIV(dev)->subs_tail += 1;
	return 0;
}

int
failsafe_args_count_subdevice(struct rte_eth_dev *dev,
			const char *params)
{
	return fs_parse_sub_devices(fs_count_device,
				    dev, params);
}

static int
fs_parse_sub_device(struct sub_device *sdev)
{
	struct rte_devargs *da;
	char devstr[DEVARGS_MAXLEN] = "";

	da = &sdev->devargs;
	snprintf(devstr, sizeof(devstr), "%s,%s", da->name, da->args);
	return fs_parse_device(sdev, devstr);
}

int
failsafe_args_parse_subs(struct rte_eth_dev *dev)
{
	struct sub_device *sdev;
	uint8_t i;
	int ret = 0;

	FOREACH_SUBDEV(sdev, i, dev) {
		if (sdev->state >= DEV_PARSED)
			continue;
		if (sdev->cmdline)
			ret = fs_execute_cmd(sdev, sdev->cmdline);
		else if (sdev->fd_str)
			ret = fs_read_fd(sdev, sdev->fd_str);
		else
			ret = fs_parse_sub_device(sdev);
		if (ret == 0)
			sdev->state = DEV_PARSED;
	}
	return 0;
}