/* Copyright (c) 2002-2017 Dovecot authors, see the included COPYING file
 */

#include "lib.h"
#include "ioloop.h"
#include "array.h"
#include "str.h"
#include "safe-mkstemp.h"
#include "istream-private.h"
#include "istream-seekable.h"
#include "ostream.h"
#include "lib-signals.h"

#include "program-client-private.h"

#include <unistd.h>

#define MAX_OUTPUT_BUFFER_SIZE 16384
#define MAX_OUTPUT_MEMORY_BUFFER (1024*128)

static
void program_client_callback(struct program_client *pclient, int result, void *context)
{
	/* do not call callback when destroying */
	if (pclient->destroying) return;
	program_client_callback_t *callback = pclient->callback;
	i_assert(pclient->callback != NULL);
	callback(result, context);
}

static
int program_client_seekable_fd_callback(const char **path_r, void *context)
{
	struct program_client *pclient = (struct program_client *)context;
	string_t *path;
	int fd;

	path = t_str_new(128);
	str_append(path, pclient->temp_prefix);
	fd = safe_mkstemp(path, 0600, (uid_t)-1, (gid_t)-1);
	if (fd == -1) {
		i_error("safe_mkstemp(%s) failed: %m", str_c(path));
		return -1;
	}

	/* we just want the fd, unlink it */
	if (i_unlink(str_c(path)) < 0) {
		/* shouldn't happen.. */
		i_close_fd(&fd);
		return -1;
	}

	*path_r = str_c(path);
	return fd;
}

static
void program_client_timeout(struct program_client *pclient)
{
	i_error("program `%s' execution timed out (> %u msecs)",
		pclient->path, pclient->set.input_idle_timeout_msecs);
	program_client_fail(pclient, PROGRAM_CLIENT_ERROR_RUN_TIMEOUT);
}

static
void program_client_connect_timeout(struct program_client *pclient)
{
	i_error("program `%s' socket connection timed out (> %u msecs)",
		pclient->path, pclient->set.client_connect_timeout_msecs);
	program_client_fail(pclient, PROGRAM_CLIENT_ERROR_CONNECT_TIMEOUT);
}

static
int program_client_connect(struct program_client *pclient)
{
	if (pclient->set.client_connect_timeout_msecs != 0) {
		pclient->to = timeout_add(pclient->set.client_connect_timeout_msecs,
					  program_client_connect_timeout, pclient);
	}

	return pclient->connect(pclient);
}

static
int program_client_close_output(struct program_client *pclient)
{
	int ret;

	if (pclient->program_output != NULL)
		o_stream_destroy(&pclient->program_output);
	if ((ret = pclient->close_output(pclient)) < 0)
		return -1;
	pclient->program_output = NULL;

	return ret;
}

static
void program_client_disconnect_extra_fds(struct program_client *pclient)
{
	struct program_client_extra_fd *efds;
	unsigned int i, count;

	if (!array_is_created(&pclient->extra_fds))
		return;

	efds = array_get_modifiable(&pclient->extra_fds, &count);
	for(i = 0; i < count; i++) {
		if (efds[i].input != NULL)
			i_stream_unref(&efds[i].input);
		if (efds[i].io != NULL)
			io_remove(&efds[i].io);
		if (efds[i].parent_fd != -1 && close(efds[i].parent_fd) < 0)
			i_error("close(fd=%d) failed: %m", efds[i].parent_fd);
	}
}

void program_client_disconnected(struct program_client *pclient)
{
	if (pclient->program_input != NULL) {
		if (pclient->output_seekable)
			i_stream_unref(&pclient->program_input);
		else
			i_stream_destroy(&pclient->program_input);
	}
	if (pclient->program_output != NULL)
		o_stream_destroy(&pclient->program_output);

	if (pclient->io != NULL)
		io_remove(&pclient->io);

	if (pclient->fd_in != -1 && close(pclient->fd_in) < 0)
		i_error("close(%s) failed: %m", pclient->path);
	if (pclient->fd_out != -1 && pclient->fd_out != pclient->fd_in
	    && close(pclient->fd_out) < 0)
		i_error("close(%s/out) failed: %m", pclient->path);
	pclient->fd_in = pclient->fd_out = -1;

	pclient->disconnected = TRUE;

	if (pclient->other_error && pclient->error == PROGRAM_CLIENT_ERROR_NONE) {
		pclient->error = PROGRAM_CLIENT_ERROR_OTHER;
	}

	program_client_callback(pclient,
		pclient->error != PROGRAM_CLIENT_ERROR_NONE ?
			-1 :
			pclient->exit_code,
		pclient->context);
}

static
void program_client_disconnect(struct program_client *pclient, bool force)
{
	int ret;

	if (pclient->disconnected)
		return;
	pclient->disconnected = TRUE;

	if (pclient->to != NULL)
		timeout_remove(&pclient->to);
	if (pclient->io != NULL)
		io_remove(&pclient->io);

	if ((ret = program_client_close_output(pclient)) < 0)
		pclient->other_error = TRUE;

	program_client_disconnect_extra_fds(pclient);

	pclient->disconnect(pclient, force);
}

void program_client_fail(struct program_client *pclient, enum program_client_error error)
{
	if (pclient->error != PROGRAM_CLIENT_ERROR_NONE)
		return;

	pclient->error = error;
	program_client_disconnect(pclient, TRUE);
}

static
bool program_client_input_pending(struct program_client *pclient)
{
	struct program_client_extra_fd *efds = NULL;
	unsigned int count, i;

	if (pclient->program_input != NULL &&
	    !pclient->program_input->closed &&
	    !i_stream_is_eof(pclient->program_input)) {
		return TRUE;
	}

	if (array_is_created(&pclient->extra_fds)) {
		efds = array_get_modifiable(&pclient->extra_fds, &count);
		for(i = 0; i < count; i++) {
			if (efds[i].input != NULL &&
			    !efds[i].input->closed &&
			    !i_stream_is_eof(efds[i].input)) {
				return TRUE;
			}
		}
	}

	return FALSE;
}

static
int program_client_program_output(struct program_client *pclient)
{
	struct istream *input = pclient->input;
	struct ostream *output = pclient->program_output;
	const unsigned char *data;
	size_t size;
	int ret = 0;

	if ((ret = o_stream_flush(output)) <= 0) {
		if (ret < 0) {
			i_error("write(%s) failed: %s",
				o_stream_get_name(output),
				o_stream_get_error(output));
			program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
		}

		return ret;
	}

	if (input != NULL && output != NULL) {
		do {
			while ((data=i_stream_get_data(input, &size)) != NULL) {
				ssize_t sent;

				if ((sent=o_stream_send(output, data, size)) < 0) {
					i_error("write(%s) failed: %s",
						o_stream_get_name(output),
						o_stream_get_error(output));
					program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
					return -1;
				}

				if (sent == 0)
					return 0;
				i_stream_skip(input, sent);
			}
		} while ((ret = i_stream_read(input)) > 0);

		if (ret == 0)
			return 1;

		if (ret < 0) {
			if (input->stream_errno != 0) {
				i_error("read(%s) failed: %s",
					i_stream_get_name(input),
					i_stream_get_error(input));
				program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
				return -1;
			} else if (!i_stream_have_bytes_left(input)) {
				i_stream_unref(&pclient->input);
				input = NULL;

				if ((ret = o_stream_flush(output)) <= 0) {
					if (ret < 0) {
						i_error("write(%s) failed: %s",
							o_stream_get_name(output),
							o_stream_get_error(output));
						program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
					}
					return ret;
				}
			}
		}
	}

	if (input == NULL) {
		if (!program_client_input_pending(pclient)) {
			program_client_disconnect(pclient, FALSE);
		} else if (program_client_close_output(pclient) < 0) {
			program_client_fail(pclient,
					    PROGRAM_CLIENT_ERROR_OTHER);
		}
	}
	return 1;
}

void program_client_program_input(struct program_client *pclient)
{
	struct istream *input = pclient->program_input;
	struct ostream *output = pclient->output;
	const unsigned char *data;
	size_t size;
	int ret = 0;

	if (pclient->output_seekable && pclient->seekable_output == NULL) {
		struct istream *input_list[2] = { input, NULL };

		input = i_stream_create_seekable(input_list, MAX_OUTPUT_MEMORY_BUFFER,
						 program_client_seekable_fd_callback,
						 pclient);
		i_stream_unref(&pclient->program_input);
		pclient->program_input = input;

		pclient->seekable_output = input;
		i_stream_ref(pclient->seekable_output);
	}

	if (input != NULL) {
		while ((ret = i_stream_read_data(input, &data, &size, 0)) > 0) {
			if (output != NULL) {
				ssize_t sent;

				if ((sent=o_stream_send(output, data, size)) < 0) {
					i_error("write(%s) failed: %s",
						o_stream_get_name(output),
						o_stream_get_error(output));
					program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
					return;
				}
				if (sent == 0)
					return;
				size = (size_t)sent;
			}

			i_stream_skip(input, size);
		}

		if (ret < 0) {
			if (input->stream_errno != 0) {
				i_error("read(%s) failed: %s",
					i_stream_get_name(input),
					i_stream_get_error(input));
				program_client_fail(pclient, PROGRAM_CLIENT_ERROR_IO);
				return;
			} else {
				if (!program_client_input_pending(pclient)) {
					program_client_disconnect(pclient, FALSE);
					return;
				}
			}
		}
		if (program_client_input_pending(pclient))
			return;
		if (pclient->program_input != NULL && !input->eof) {
			program_client_fail(pclient,
					    PROGRAM_CLIENT_ERROR_IO);
			return;
		}
	}
	program_client_disconnect(pclient, FALSE);
}

static
void program_client_extra_fd_input(struct program_client_extra_fd *efd)
{
	struct program_client *pclient = efd->pclient;

	i_assert(efd->callback != NULL);
	efd->callback(efd->context, efd->input);

	if (efd->input->closed || i_stream_is_eof(efd->input)) {
		if (!program_client_input_pending(pclient))
			program_client_disconnect(pclient, FALSE);
	}
}

int program_client_connected(struct program_client *pclient)
{
	int ret = 1;

	pclient->start_time = ioloop_timeval;
	if (pclient->to != NULL)
		timeout_remove(&pclient->to);
	if (pclient->set.input_idle_timeout_msecs != 0) {
		pclient->to =
			timeout_add(pclient->set.input_idle_timeout_msecs,
				    program_client_timeout, pclient);
	}

	/* run output */
	if (pclient->program_output != NULL &&
	    (ret = program_client_program_output(pclient)) == 0) {
		if (pclient->program_output != NULL) {
			o_stream_set_flush_callback(pclient->program_output,
				 program_client_program_output, pclient);
		}
	}

	return ret;
}

void program_client_init(struct program_client *pclient, pool_t pool, const char *path,
			 const char *const *args, const struct program_client_settings *set)
{
	pclient->pool = pool;
	pclient->path = p_strdup(pool, path);
	if (args != NULL)
		pclient->args = p_strarray_dup(pool, args);
	pclient->set = *set;
	pclient->debug = set->debug;
	pclient->fd_in = -1;
	pclient->fd_out = -1;
}

void program_client_set_input(struct program_client *pclient, struct istream *input)
{
	if (pclient->input != NULL)
		i_stream_unref(&pclient->input);
	if (input != NULL)
		i_stream_ref(input);
	pclient->input = input;
}

void program_client_set_output(struct program_client *pclient, struct ostream *output)
{
	if (pclient->output != NULL)
		o_stream_unref(&pclient->output);
	if (output != NULL)
		o_stream_ref(output);
	pclient->output = output;
	pclient->output_seekable = FALSE;
	i_free(pclient->temp_prefix);
}

void program_client_set_output_seekable(struct program_client *pclient, const char *temp_prefix)
{
	if (pclient->output != NULL)
		o_stream_unref(&pclient->output);
	pclient->temp_prefix = i_strdup(temp_prefix);
	pclient->output_seekable = TRUE;
}

struct istream *program_client_get_output_seekable(struct program_client *pclient)
{
	struct istream *input = pclient->seekable_output;

	pclient->seekable_output = NULL;

	i_stream_seek(input, 0);
	return input;
}

#undef program_client_set_extra_fd
void program_client_set_extra_fd(struct program_client *pclient, int fd,
				 program_client_fd_callback_t *callback, void *context)
{
	struct program_client_extra_fd *efds;
	struct program_client_extra_fd *efd = NULL;
	unsigned int i, count;
	i_assert(fd > 1);

	if (!array_is_created(&pclient->extra_fds))
		p_array_init(&pclient->extra_fds, pclient->pool, 2);

	efds = array_get_modifiable(&pclient->extra_fds, &count);
	for(i = 0; i < count; i++) {
		if (efds[i].child_fd == fd) {
			efd = &efds[i];
			break;
		}
	}

	if (efd == NULL) {
		efd = array_append_space(&pclient->extra_fds);
		efd->pclient = pclient;
		efd->child_fd = fd;
		efd->parent_fd = -1;
	}
	efd->callback = callback;
	efd->context = context;
}

void program_client_set_env(struct program_client *pclient, const char *name, const char *value)
{
	const char *env;

	if (!array_is_created(&pclient->envs))
		p_array_init(&pclient->envs, pclient->pool, 16);

	env = p_strdup_printf(pclient->pool, "%s=%s", name, value);
	array_append(&pclient->envs, &env, 1);
}

void program_client_init_streams(struct program_client *pclient)
{
	/* Create streams for normal program I/O */
	if (pclient->fd_out >= 0) {
		pclient->program_output =
			o_stream_create_fd(pclient->fd_out,
					   MAX_OUTPUT_BUFFER_SIZE, FALSE);
		o_stream_set_name(pclient->program_output, "program stdin");
	}
	if (pclient->fd_in >= 0) {
		struct istream *input;

		input = i_stream_create_fd(pclient->fd_in, (size_t)-1, FALSE);

		pclient->program_input = input;
		i_stream_set_name(pclient->program_input, "program stdout");

		pclient->io = io_add(pclient->fd_in, IO_READ,
				     program_client_program_input, pclient);
	}

	/* Create streams for additional output through side-channel fds */
	if (array_is_created(&pclient->extra_fds)) {
		struct program_client_extra_fd *efds = NULL;
		unsigned int count, i;

		efds = array_get_modifiable(&pclient->extra_fds, &count);
		for(i = 0; i < count; i++) {
			i_assert(efds[i].parent_fd >= 0);
			efds[i].input = i_stream_create_fd
				(efds[i].parent_fd, (size_t)-1, FALSE);
			i_stream_set_name(efds[i].input,
					  t_strdup_printf("program output fd=%d",
							  efds[i].child_fd));
			efds[i].io = io_add(efds[i].parent_fd, IO_READ,
					    program_client_extra_fd_input, &efds[i]);
		}
	}
}

void program_client_destroy(struct program_client **_pclient)
{
	struct program_client *pclient = *_pclient;
	*_pclient = NULL;

	pclient->destroying = TRUE;
	pclient->callback = NULL;

	program_client_disconnect(pclient, TRUE);

	i_assert(pclient->callback == NULL);

	if (pclient->input != NULL)
		i_stream_unref(&pclient->input);
	if (pclient->program_input != NULL)
		i_stream_unref(&pclient->program_input);
	if (pclient->program_output != NULL)
		o_stream_unref(&pclient->program_output);
	if (pclient->output != NULL)
		o_stream_unref(&pclient->output);
	if (pclient->seekable_output != NULL)
		i_stream_unref(&pclient->seekable_output);

	if (pclient->io != NULL)
		io_remove(&pclient->io);
	i_free(pclient->temp_prefix);

	if (pclient->destroy != NULL)
		pclient->destroy(pclient);

	pool_unref(&pclient->pool);
}

void program_client_switch_ioloop(struct program_client *pclient)
{
	if (pclient->input != NULL)
		i_stream_switch_ioloop(pclient->input);
	if (pclient->program_input != NULL)
		i_stream_switch_ioloop(pclient->program_input);
	if (pclient->seekable_output != NULL)
		i_stream_switch_ioloop(pclient->seekable_output);
	if (pclient->output != NULL)
		o_stream_switch_ioloop(pclient->output);
	if (pclient->program_output != NULL)
		o_stream_switch_ioloop(pclient->program_output);
	if (pclient->to != NULL)
		pclient->to = io_loop_move_timeout(&pclient->to);
	if (pclient->io != NULL)
		pclient->io = io_loop_move_io(&pclient->io);
	pclient->switch_ioloop(pclient);
}

int program_client_create(const char *uri, const char *const *args,
			  const struct program_client_settings *set,
			  bool noreply, struct program_client **pc_r,
			  const char **error_r)
{
	if (strncmp(uri, "exec:", 5) == 0) {
		*pc_r = program_client_local_create(
			uri+5,
			args,
			set);
		return 0;
	} else if (strncmp(uri, "unix:", 5) == 0) {
		*pc_r = program_client_remote_create(
			uri+5,
			args,
			set, noreply);
		return 0;
	} else {
		*error_r = t_strdup_printf(
			"Unsupported program client scheme '%s'",
			t_strcut(uri, ':'));
		return -1;
	}
}


static
void program_client_run_callback(int result, int *context)
{
	*context = result;
	io_loop_stop(current_ioloop);
}

int program_client_run(struct program_client *pclient)
{
	int ret = -2;
	struct ioloop *prev_ioloop = current_ioloop;
	struct ioloop *ioloop = io_loop_create();

	program_client_switch_ioloop(pclient);

	program_client_run_async(pclient, program_client_run_callback, &ret);

	if (ret == -2) {
		io_loop_run(ioloop);
	}

	io_loop_set_current(prev_ioloop);
	program_client_switch_ioloop(pclient);
	io_loop_set_current(ioloop);
	io_loop_destroy(&ioloop);

	if (pclient->error != PROGRAM_CLIENT_ERROR_NONE)
		return -1;

	return pclient->exit_code;
}

#undef program_client_run_async
void program_client_run_async(struct program_client *pclient, program_client_callback_t *callback, void *context)
{
	int ret;

	i_assert(callback != NULL);

	pclient->disconnected = FALSE;
	pclient->exit_code = 1;
	pclient->error = PROGRAM_CLIENT_ERROR_NONE;

	pclient->callback = callback;
	pclient->context = context;
	if ((ret = program_client_connect(pclient)) >= 0) {
		/* run output */
		if (ret > 0 && pclient->program_output != NULL &&
		    (ret = o_stream_flush(pclient->program_output)) == 0) {
			o_stream_set_flush_callback
				(pclient->program_output,
				 program_client_program_output, pclient);
		}
		if (ret < 0) {
			i_error("write(%s) failed: %s",
				o_stream_get_name(pclient->program_output),
				o_stream_get_error(pclient->program_output));
			pclient->error = PROGRAM_CLIENT_ERROR_IO;
			program_client_callback(pclient, ret, context);
			return;
		}
	}
}