665 lines
20 KiB
C
665 lines
20 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <fcntl.h>
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#include <getopt.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/un.h>
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#include <unistd.h>
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#include "sd-daemon.h"
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#include "sd-event.h"
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#include "sd-resolve.h"
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#include "alloc-util.h"
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#include "errno-util.h"
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#include "fd-util.h"
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#include "log.h"
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#include "main-func.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "pretty-print.h"
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#include "resolve-private.h"
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#include "set.h"
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#include "socket-util.h"
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#include "string-util.h"
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#include "util.h"
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#define BUFFER_SIZE (256 * 1024)
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static unsigned arg_connections_max = 256;
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static const char *arg_remote_host = NULL;
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typedef struct Context {
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sd_event *event;
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sd_resolve *resolve;
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Set *listen;
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Set *connections;
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} Context;
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typedef struct Connection {
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Context *context;
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int server_fd, client_fd;
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int server_to_client_buffer[2]; /* a pipe */
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int client_to_server_buffer[2]; /* a pipe */
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size_t server_to_client_buffer_full, client_to_server_buffer_full;
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size_t server_to_client_buffer_size, client_to_server_buffer_size;
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sd_event_source *server_event_source, *client_event_source;
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sd_resolve_query *resolve_query;
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} Connection;
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static void connection_free(Connection *c) {
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assert(c);
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if (c->context)
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set_remove(c->context->connections, c);
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sd_event_source_unref(c->server_event_source);
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sd_event_source_unref(c->client_event_source);
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safe_close(c->server_fd);
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safe_close(c->client_fd);
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safe_close_pair(c->server_to_client_buffer);
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safe_close_pair(c->client_to_server_buffer);
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sd_resolve_query_unref(c->resolve_query);
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free(c);
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}
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static void context_clear(Context *context) {
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assert(context);
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set_free_with_destructor(context->listen, sd_event_source_unref);
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set_free_with_destructor(context->connections, connection_free);
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sd_event_unref(context->event);
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sd_resolve_unref(context->resolve);
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}
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static int connection_create_pipes(Connection *c, int buffer[static 2], size_t *sz) {
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int r;
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assert(c);
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assert(buffer);
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assert(sz);
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if (buffer[0] >= 0)
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return 0;
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r = pipe2(buffer, O_CLOEXEC|O_NONBLOCK);
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if (r < 0)
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return log_error_errno(errno, "Failed to allocate pipe buffer: %m");
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(void) fcntl(buffer[0], F_SETPIPE_SZ, BUFFER_SIZE);
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r = fcntl(buffer[0], F_GETPIPE_SZ);
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if (r < 0)
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return log_error_errno(errno, "Failed to get pipe buffer size: %m");
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assert(r > 0);
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*sz = r;
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return 0;
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}
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static int connection_shovel(
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Connection *c,
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int *from, int buffer[2], int *to,
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size_t *full, size_t *sz,
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sd_event_source **from_source, sd_event_source **to_source) {
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bool shoveled;
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assert(c);
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assert(from);
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assert(buffer);
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assert(buffer[0] >= 0);
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assert(buffer[1] >= 0);
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assert(to);
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assert(full);
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assert(sz);
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assert(from_source);
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assert(to_source);
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do {
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ssize_t z;
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shoveled = false;
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if (*full < *sz && *from >= 0 && *to >= 0) {
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z = splice(*from, NULL, buffer[1], NULL, *sz - *full, SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
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if (z > 0) {
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*full += z;
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shoveled = true;
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} else if (z == 0 || ERRNO_IS_DISCONNECT(errno)) {
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*from_source = sd_event_source_unref(*from_source);
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*from = safe_close(*from);
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} else if (!IN_SET(errno, EAGAIN, EINTR))
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return log_error_errno(errno, "Failed to splice: %m");
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}
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if (*full > 0 && *to >= 0) {
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z = splice(buffer[0], NULL, *to, NULL, *full, SPLICE_F_MOVE|SPLICE_F_NONBLOCK);
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if (z > 0) {
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*full -= z;
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shoveled = true;
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} else if (z == 0 || ERRNO_IS_DISCONNECT(errno)) {
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*to_source = sd_event_source_unref(*to_source);
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*to = safe_close(*to);
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} else if (!IN_SET(errno, EAGAIN, EINTR))
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return log_error_errno(errno, "Failed to splice: %m");
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}
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} while (shoveled);
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return 0;
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}
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static int connection_enable_event_sources(Connection *c);
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static int traffic_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
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Connection *c = userdata;
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int r;
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assert(s);
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assert(fd >= 0);
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assert(c);
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r = connection_shovel(c,
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&c->server_fd, c->server_to_client_buffer, &c->client_fd,
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&c->server_to_client_buffer_full, &c->server_to_client_buffer_size,
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&c->server_event_source, &c->client_event_source);
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if (r < 0)
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goto quit;
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r = connection_shovel(c,
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&c->client_fd, c->client_to_server_buffer, &c->server_fd,
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&c->client_to_server_buffer_full, &c->client_to_server_buffer_size,
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&c->client_event_source, &c->server_event_source);
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if (r < 0)
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goto quit;
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/* EOF on both sides? */
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if (c->server_fd == -1 && c->client_fd == -1)
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goto quit;
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/* Server closed, and all data written to client? */
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if (c->server_fd == -1 && c->server_to_client_buffer_full <= 0)
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goto quit;
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/* Client closed, and all data written to server? */
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if (c->client_fd == -1 && c->client_to_server_buffer_full <= 0)
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goto quit;
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r = connection_enable_event_sources(c);
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if (r < 0)
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goto quit;
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return 1;
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quit:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int connection_enable_event_sources(Connection *c) {
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uint32_t a = 0, b = 0;
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int r;
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assert(c);
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if (c->server_to_client_buffer_full > 0)
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b |= EPOLLOUT;
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if (c->server_to_client_buffer_full < c->server_to_client_buffer_size)
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a |= EPOLLIN;
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if (c->client_to_server_buffer_full > 0)
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a |= EPOLLOUT;
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if (c->client_to_server_buffer_full < c->client_to_server_buffer_size)
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b |= EPOLLIN;
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if (c->server_event_source)
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r = sd_event_source_set_io_events(c->server_event_source, a);
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else if (c->server_fd >= 0)
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r = sd_event_add_io(c->context->event, &c->server_event_source, c->server_fd, a, traffic_cb, c);
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else
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r = 0;
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if (r < 0)
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return log_error_errno(r, "Failed to set up server event source: %m");
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if (c->client_event_source)
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r = sd_event_source_set_io_events(c->client_event_source, b);
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else if (c->client_fd >= 0)
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r = sd_event_add_io(c->context->event, &c->client_event_source, c->client_fd, b, traffic_cb, c);
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else
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r = 0;
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if (r < 0)
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return log_error_errno(r, "Failed to set up client event source: %m");
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return 0;
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}
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static int connection_complete(Connection *c) {
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int r;
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assert(c);
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r = connection_create_pipes(c, c->server_to_client_buffer, &c->server_to_client_buffer_size);
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if (r < 0)
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goto fail;
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r = connection_create_pipes(c, c->client_to_server_buffer, &c->client_to_server_buffer_size);
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if (r < 0)
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goto fail;
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r = connection_enable_event_sources(c);
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if (r < 0)
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goto fail;
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return 0;
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fail:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int connect_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
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Connection *c = userdata;
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socklen_t solen;
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int error, r;
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assert(s);
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assert(fd >= 0);
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assert(c);
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solen = sizeof(error);
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r = getsockopt(fd, SOL_SOCKET, SO_ERROR, &error, &solen);
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if (r < 0) {
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log_error_errno(errno, "Failed to issue SO_ERROR: %m");
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goto fail;
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}
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if (error != 0) {
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log_error_errno(error, "Failed to connect to remote host: %m");
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goto fail;
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}
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c->client_event_source = sd_event_source_unref(c->client_event_source);
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return connection_complete(c);
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fail:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int connection_start(Connection *c, struct sockaddr *sa, socklen_t salen) {
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int r;
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assert(c);
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assert(sa);
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assert(salen);
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c->client_fd = socket(sa->sa_family, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
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if (c->client_fd < 0) {
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log_error_errno(errno, "Failed to get remote socket: %m");
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goto fail;
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}
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r = connect(c->client_fd, sa, salen);
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if (r < 0) {
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if (errno == EINPROGRESS) {
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r = sd_event_add_io(c->context->event, &c->client_event_source, c->client_fd, EPOLLOUT, connect_cb, c);
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if (r < 0) {
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log_error_errno(r, "Failed to add connection socket: %m");
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goto fail;
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}
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r = sd_event_source_set_enabled(c->client_event_source, SD_EVENT_ONESHOT);
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if (r < 0) {
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log_error_errno(r, "Failed to enable oneshot event source: %m");
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goto fail;
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}
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} else {
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log_error_errno(errno, "Failed to connect to remote host: %m");
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goto fail;
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}
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} else {
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r = connection_complete(c);
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if (r < 0)
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goto fail;
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}
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return 0;
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fail:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int resolve_handler(sd_resolve_query *q, int ret, const struct addrinfo *ai, Connection *c) {
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assert(q);
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assert(c);
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if (ret != 0) {
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log_error("Failed to resolve host: %s", gai_strerror(ret));
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goto fail;
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}
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c->resolve_query = sd_resolve_query_unref(c->resolve_query);
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return connection_start(c, ai->ai_addr, ai->ai_addrlen);
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fail:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int resolve_remote(Connection *c) {
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static const struct addrinfo hints = {
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.ai_family = AF_UNSPEC,
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.ai_socktype = SOCK_STREAM,
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.ai_flags = AI_ADDRCONFIG
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};
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union sockaddr_union sa = {};
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const char *node, *service;
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int r;
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if (IN_SET(arg_remote_host[0], '/', '@')) {
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int salen;
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salen = sockaddr_un_set_path(&sa.un, arg_remote_host);
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if (salen < 0) {
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log_error_errno(salen, "Specified address doesn't fit in an AF_UNIX address, refusing: %m");
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goto fail;
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}
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return connection_start(c, &sa.sa, salen);
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}
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service = strrchr(arg_remote_host, ':');
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if (service) {
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node = strndupa(arg_remote_host, service - arg_remote_host);
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service++;
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} else {
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node = arg_remote_host;
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service = "80";
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}
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log_debug("Looking up address info for %s:%s", node, service);
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r = resolve_getaddrinfo(c->context->resolve, &c->resolve_query, node, service, &hints, resolve_handler, NULL, c);
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if (r < 0) {
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log_error_errno(r, "Failed to resolve remote host: %m");
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goto fail;
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}
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return 0;
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fail:
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connection_free(c);
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return 0; /* ignore errors, continue serving */
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}
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static int add_connection_socket(Context *context, int fd) {
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Connection *c;
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int r;
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assert(context);
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assert(fd >= 0);
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if (set_size(context->connections) > arg_connections_max) {
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log_warning("Hit connection limit, refusing connection.");
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safe_close(fd);
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return 0;
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}
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r = set_ensure_allocated(&context->connections, NULL);
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if (r < 0) {
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log_oom();
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return 0;
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}
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c = new0(Connection, 1);
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if (!c) {
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log_oom();
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return 0;
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}
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c->context = context;
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c->server_fd = fd;
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c->client_fd = -1;
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c->server_to_client_buffer[0] = c->server_to_client_buffer[1] = -1;
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c->client_to_server_buffer[0] = c->client_to_server_buffer[1] = -1;
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r = set_put(context->connections, c);
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if (r < 0) {
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free(c);
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log_oom();
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return 0;
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}
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return resolve_remote(c);
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}
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static int accept_cb(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
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_cleanup_free_ char *peer = NULL;
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Context *context = userdata;
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int nfd = -1, r;
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assert(s);
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assert(fd >= 0);
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assert(revents & EPOLLIN);
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assert(context);
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nfd = accept4(fd, NULL, NULL, SOCK_NONBLOCK|SOCK_CLOEXEC);
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if (nfd < 0) {
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if (!ERRNO_IS_ACCEPT_AGAIN(errno))
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log_warning_errno(errno, "Failed to accept() socket: %m");
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} else {
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(void) getpeername_pretty(nfd, true, &peer);
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log_debug("New connection from %s", strna(peer));
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r = add_connection_socket(context, nfd);
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if (r < 0) {
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log_error_errno(r, "Failed to accept connection, ignoring: %m");
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safe_close(fd);
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}
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}
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r = sd_event_source_set_enabled(s, SD_EVENT_ONESHOT);
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if (r < 0) {
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log_error_errno(r, "Error while re-enabling listener with ONESHOT: %m");
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sd_event_exit(context->event, r);
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return r;
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}
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return 1;
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}
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static int add_listen_socket(Context *context, int fd) {
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sd_event_source *source;
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int r;
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assert(context);
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assert(fd >= 0);
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r = set_ensure_allocated(&context->listen, NULL);
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if (r < 0) {
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log_oom();
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return r;
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}
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r = sd_is_socket(fd, 0, SOCK_STREAM, 1);
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if (r < 0)
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return log_error_errno(r, "Failed to determine socket type: %m");
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if (r == 0)
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return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
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"Passed in socket is not a stream socket.");
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r = fd_nonblock(fd, true);
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if (r < 0)
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return log_error_errno(r, "Failed to mark file descriptor non-blocking: %m");
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r = sd_event_add_io(context->event, &source, fd, EPOLLIN, accept_cb, context);
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if (r < 0)
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return log_error_errno(r, "Failed to add event source: %m");
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r = set_put(context->listen, source);
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if (r < 0) {
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log_error_errno(r, "Failed to add source to set: %m");
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sd_event_source_unref(source);
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return r;
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}
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/* Set the watcher to oneshot in case other processes are also
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* watching to accept(). */
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r = sd_event_source_set_enabled(source, SD_EVENT_ONESHOT);
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if (r < 0)
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return log_error_errno(r, "Failed to enable oneshot mode: %m");
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return 0;
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}
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static int help(void) {
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_cleanup_free_ char *link = NULL;
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|
int r;
|
|
|
|
r = terminal_urlify_man("systemd-socket-proxyd", "8", &link);
|
|
if (r < 0)
|
|
return log_oom();
|
|
|
|
printf("%1$s [HOST:PORT]\n"
|
|
"%1$s [SOCKET]\n\n"
|
|
"Bidirectionally proxy local sockets to another (possibly remote) socket.\n\n"
|
|
" -c --connections-max= Set the maximum number of connections to be accepted\n"
|
|
" -h --help Show this help\n"
|
|
" --version Show package version\n"
|
|
"\nSee the %2$s for details.\n"
|
|
, program_invocation_short_name
|
|
, link
|
|
);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int parse_argv(int argc, char *argv[]) {
|
|
|
|
enum {
|
|
ARG_VERSION = 0x100,
|
|
ARG_IGNORE_ENV
|
|
};
|
|
|
|
static const struct option options[] = {
|
|
{ "connections-max", required_argument, NULL, 'c' },
|
|
{ "help", no_argument, NULL, 'h' },
|
|
{ "version", no_argument, NULL, ARG_VERSION },
|
|
{}
|
|
};
|
|
|
|
int c, r;
|
|
|
|
assert(argc >= 0);
|
|
assert(argv);
|
|
|
|
while ((c = getopt_long(argc, argv, "c:h", options, NULL)) >= 0)
|
|
|
|
switch (c) {
|
|
|
|
case 'h':
|
|
return help();
|
|
|
|
case ARG_VERSION:
|
|
return version();
|
|
|
|
case 'c':
|
|
r = safe_atou(optarg, &arg_connections_max);
|
|
if (r < 0) {
|
|
log_error("Failed to parse --connections-max= argument: %s", optarg);
|
|
return r;
|
|
}
|
|
|
|
if (arg_connections_max < 1)
|
|
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
|
"Connection limit is too low.");
|
|
|
|
break;
|
|
|
|
case '?':
|
|
return -EINVAL;
|
|
|
|
default:
|
|
assert_not_reached("Unhandled option");
|
|
}
|
|
|
|
if (optind >= argc)
|
|
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
|
"Not enough parameters.");
|
|
|
|
if (argc != optind+1)
|
|
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
|
|
"Too many parameters.");
|
|
|
|
arg_remote_host = argv[optind];
|
|
return 1;
|
|
}
|
|
|
|
static int run(int argc, char *argv[]) {
|
|
_cleanup_(context_clear) Context context = {};
|
|
int r, n, fd;
|
|
|
|
log_parse_environment();
|
|
log_open();
|
|
|
|
r = parse_argv(argc, argv);
|
|
if (r <= 0)
|
|
return r;
|
|
|
|
r = sd_event_default(&context.event);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to allocate event loop: %m");
|
|
|
|
r = sd_resolve_default(&context.resolve);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to allocate resolver: %m");
|
|
|
|
r = sd_resolve_attach_event(context.resolve, context.event, 0);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to attach resolver: %m");
|
|
|
|
sd_event_set_watchdog(context.event, true);
|
|
|
|
r = sd_listen_fds(1);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to receive sockets from parent.");
|
|
if (r == 0)
|
|
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "Didn't get any sockets passed in.");
|
|
|
|
n = r;
|
|
|
|
for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {
|
|
r = add_listen_socket(&context, fd);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
r = sd_event_loop(context.event);
|
|
if (r < 0)
|
|
return log_error_errno(r, "Failed to run event loop: %m");
|
|
|
|
return 0;
|
|
}
|
|
|
|
DEFINE_MAIN_FUNCTION(run);
|