/* Copyright (c) 2002-2018 Pigeonhole authors, see the included COPYING file
 */

#include "lib.h"
#include "str.h"
#include "buffer.h"
#include "env-util.h"
#include "execv-const.h"
#include "master-service.h"
#include "settings-parser.h"
#include "config-parser-private.h"
#include "managesieve-login-settings-plugin.h"

#include <stddef.h>
#include <unistd.h>
#include <sys/wait.h>
#include <sysexits.h>

typedef enum { CAP_SIEVE, CAP_NOTIFY } capability_type_t;

bool capability_dumped = FALSE;
static char *capability_sieve = NULL;
static char *capability_notify = NULL;

static void (*next_hook_config_parser_begin)(struct config_parser_context *ctx) = NULL;

static void managesieve_login_config_parser_begin(struct config_parser_context *ctx);

const char *managesieve_login_settings_version = DOVECOT_ABI_VERSION;

void managesieve_login_settings_init(struct module *module ATTR_UNUSED)
{
	next_hook_config_parser_begin = hook_config_parser_begin;
	hook_config_parser_begin = managesieve_login_config_parser_begin;
}

void managesieve_login_settings_deinit(void)
{
	hook_config_parser_begin = next_hook_config_parser_begin;

	if ( capability_sieve != NULL )
		i_free(capability_sieve);

	if ( capability_notify != NULL )
		i_free(capability_notify);
}

static void capability_store(capability_type_t cap_type, const char *value)
{
	switch ( cap_type ) {
	case CAP_SIEVE:
		capability_sieve = i_strdup(value);
		break;
	case CAP_NOTIFY:
		capability_notify = i_strdup(value);
		break;
	}
}

static void capability_parse(const char *cap_string)
{
	capability_type_t cap_type = CAP_SIEVE;
	const char *p = cap_string;
	string_t *part = t_str_new(256);

	if ( cap_string == NULL || *cap_string == '\0' ) {
		i_warning("managesieve-login: capability string is empty.");
		return;
	}

	while ( *p != '\0' ) {
		if ( *p == '\\' ) {
			p++;
			if ( *p != '\0' ) {
				str_append_c(part, *p);
				p++;
			} else break;
		} else if ( *p == ':' ) {
			if ( strcasecmp(str_c(part), "SIEVE") == 0 )
				cap_type = CAP_SIEVE;
			else if ( strcasecmp(str_c(part), "NOTIFY") == 0 )
				cap_type = CAP_NOTIFY;
			else
				i_warning("managesieve-login: unknown capability '%s' listed in "
					"capability string (ignored).", str_c(part));
			str_truncate(part, 0);
		} else if ( *p == ',' ) {
			capability_store(cap_type, str_c(part));
			str_truncate(part, 0);
		} else {
			/* Append character, but omit leading spaces */
			if ( str_len(part) > 0 || *p != ' ' )
				str_append_c(part, *p);
		}
		p++;
	}

	if ( str_len(part) > 0 ) {
		capability_store(cap_type, str_c(part));
	}
}

static bool capability_dump(void)
{
	char buf[4096];
	int fd[2], status = 0;
	ssize_t ret;
	unsigned int pos;
	pid_t pid;

	if ( getenv("DUMP_CAPABILITY") != NULL )
		return TRUE;

	if ( pipe(fd) < 0 ) {
		i_error("managesieve-login: dump-capability pipe() failed: %m");
		return FALSE;
	}
	fd_close_on_exec(fd[0], TRUE);
	fd_close_on_exec(fd[1], TRUE);

	if ( (pid = fork()) == (pid_t)-1 ) {
		(void)close(fd[0]); (void)close(fd[1]);
		i_error("managesieve-login: dump-capability fork() failed: %m");
		return FALSE;
	}

	if ( pid == 0 ) {
		const char *argv[5];

		/* Child */
		(void)close(fd[0]);

		if (dup2(fd[1], STDOUT_FILENO) < 0)
			i_fatal("managesieve-login: dump-capability dup2() failed: %m");

		env_put("DUMP_CAPABILITY", "1");

		argv[0] = PKG_LIBEXECDIR"/managesieve";
		argv[1] = "-k";
		argv[2] = "-c";
		argv[3] = master_service_get_config_path(master_service);
		argv[4] = NULL;
		execv_const(argv[0], argv);

		i_fatal("managesieve-login: dump-capability execv(%s) failed: %m", argv[0]);
	}

	(void)close(fd[1]);

	alarm(60);
	if (wait(&status) == -1) {
		i_error("managesieve-login: dump-capability failed: process %d got stuck",
			(int)pid);
		return FALSE;
	}
	alarm(0);

	if (status != 0) {
		(void)close(fd[0]);
		if (WIFSIGNALED(status)) {
			i_error("managesieve-login: dump-capability process "
				"killed with signal %d", WTERMSIG(status));
		} else {
			i_error("managesieve-login: dump-capability process returned %d",
				WIFEXITED(status) ? WEXITSTATUS(status) : status);
		}
		return FALSE;
	}

	pos = 0;
	while ((ret = read(fd[0], buf + pos, sizeof(buf) - pos)) > 0)
		pos += ret;

	if (ret < 0) {
		i_error("managesieve-login: read(dump-capability process) failed: %m");
		(void)close(fd[0]);
		return FALSE;
	}
	(void)close(fd[0]);

	if (pos == 0 || buf[pos-1] != '\n') {
		i_error("managesieve-login: dump-capability: Couldn't read capability "
			"(got %u bytes)", pos);
		return FALSE;
	}
	buf[pos-1] = '\0';

	capability_parse(buf);

	return TRUE;
}

static void managesieve_login_config_set
(struct config_parser_context *ctx, const char *key, const char *value)
{
	config_apply_line(ctx, key, t_strdup_printf("%s=%s", key, value), NULL);
}

static void managesieve_login_config_parser_begin(struct config_parser_context *ctx)
{	
	const char *const *module = ctx->modules;

	if ( module != NULL && *module != NULL ) {
		while ( *module != NULL ) {
			if ( strcmp(*module, "managesieve-login") == 0 )
				break;
			module++;
		}
		if ( *module == NULL )
			return;
	}

	if ( !capability_dumped ) {
		(void)capability_dump();
		capability_dumped = TRUE;
	}

	if ( capability_sieve != NULL )
		managesieve_login_config_set(ctx, "managesieve_sieve_capability", capability_sieve);

	if ( capability_notify != NULL )
		managesieve_login_config_set(ctx, "managesieve_notify_capability", capability_notify);
}