src/stdio-bridge/stdio-bridge.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2010 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <getopt.h>
  22 #include <poll.h>
  23 #include <stddef.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include "sd-bus.h"
  28 #include "sd-daemon.h"
  29
  30 #include "bus-internal.h"
  31 #include "bus-util.h"
  32 #include "build.h"
  33 #include "log.h"
  34 #include "util.h"
  35
  36 #define DEFAULT_BUS_PATH "unix:path=/run/dbus/system_bus_socket"
  37
  38 const char *arg_bus_path = DEFAULT_BUS_PATH;
  39
  40 static int help(void) {
  41
  42         printf("%s [OPTIONS...]\n\n"
  43                "STDIO or socket-activatable proxy to a given DBus endpoint.\n\n"
  44                "  -h --help              Show this help\n"
  45                "     --version           Show package version\n"
  46                "     --bus-path=PATH     Path to the kernel bus (default: %s)\n",
  47                program_invocation_short_name, DEFAULT_BUS_PATH);
  48
  49         return 0;
  50 }
  51
  52 static int parse_argv(int argc, char *argv[]) {
  53
  54         enum {
  55                 ARG_VERSION = 0x100,
  56         };
  57
  58         static const struct option options[] = {
  59                 { "help",            no_argument,       NULL, 'h'     },
  60                 { "bus-path",        required_argument, NULL, 'p'     },
  61                 { NULL,              0,                 NULL, 0       }
  62         };
  63
  64         int c;
  65
  66         assert(argc >= 0);
  67         assert(argv);
  68
  69         while ((c = getopt_long(argc, argv, "hsup:", options, NULL)) >= 0) {
  70
  71                 switch (c) {
  72
  73                 case 'h':
  74                         help();
  75                         return 0;
  76
  77                 case ARG_VERSION:
  78                         return version();
  79
  80                 case '?':
  81                         return -EINVAL;
  82
  83                 case 'p':
  84                         arg_bus_path = optarg;
  85                         break;
  86
  87                 default:
  88                         log_error("Unknown option code %c", c);
  89                         return -EINVAL;
  90                 }
  91         }
  92
  93         return 1;
  94 }
  95
  96 int main(int argc, char *argv[]) {
  97         _cleanup_(sd_bus_unrefp) sd_bus *a = NULL, *b = NULL;
  98         sd_id128_t server_id;
  99         bool is_unix;
 100         int r, in_fd, out_fd;
 101
 102         log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
 103         log_parse_environment();
 104         log_open();
 105
 106         r = parse_argv(argc, argv);
 107         if (r <= 0)
 108                 goto finish;
 109
 110         r = sd_listen_fds(0);
 111         if (r == 0) {
 112                 in_fd = STDIN_FILENO;
 113                 out_fd = STDOUT_FILENO;
 114         } else if (r == 1) {
 115                 in_fd = SD_LISTEN_FDS_START;
 116                 out_fd = SD_LISTEN_FDS_START;
 117         } else {
 118                 log_error("Illegal number of file descriptors passed.");
 119                 goto finish;
 120         }
 121
 122         is_unix =
 123                 sd_is_socket(in_fd, AF_UNIX, 0, 0) > 0 &&
 124                 sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0;
 125
 126         r = sd_bus_new(&a);
 127         if (r < 0) {
 128                 log_error_errno(r, "Failed to allocate bus: %m");
 129                 goto finish;
 130         }
 131
 132         r = sd_bus_set_address(a, arg_bus_path);
 133         if (r < 0) {
 134                 log_error_errno(r, "Failed to set address to connect to: %m");
 135                 goto finish;
 136         }
 137
 138         r = sd_bus_negotiate_fds(a, is_unix);
 139         if (r < 0) {
 140                 log_error_errno(r, "Failed to set FD negotiation: %m");
 141                 goto finish;
 142         }
 143
 144         r = sd_bus_start(a);
 145         if (r < 0) {
 146                 log_error_errno(r, "Failed to start bus client: %m");
 147                 goto finish;
 148         }
 149
 150         r = sd_bus_get_bus_id(a, &server_id);
 151         if (r < 0) {
 152                 log_error_errno(r, "Failed to get server ID: %m");
 153                 goto finish;
 154         }
 155
 156         r = sd_bus_new(&b);
 157         if (r < 0) {
 158                 log_error_errno(r, "Failed to allocate bus: %m");
 159                 goto finish;
 160         }
 161
 162         r = sd_bus_set_fd(b, in_fd, out_fd);
 163         if (r < 0) {
 164                 log_error_errno(r, "Failed to set fds: %m");
 165                 goto finish;
 166         }
 167
 168         r = sd_bus_set_server(b, 1, server_id);
 169         if (r < 0) {
 170                 log_error_errno(r, "Failed to set server mode: %m");
 171                 goto finish;
 172         }
 173
 174         r = sd_bus_negotiate_fds(b, is_unix);
 175         if (r < 0) {
 176                 log_error_errno(r, "Failed to set FD negotiation: %m");
 177                 goto finish;
 178         }
 179
 180         r = sd_bus_set_anonymous(b, true);
 181         if (r < 0) {
 182                 log_error_errno(r, "Failed to set anonymous authentication: %m");
 183                 goto finish;
 184         }
 185
 186         r = sd_bus_start(b);
 187         if (r < 0) {
 188                 log_error_errno(r, "Failed to start bus client: %m");
 189                 goto finish;
 190         }
 191
 192         for (;;) {
 193                 _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
 194                 int events_a, events_b, fd;
 195                 uint64_t timeout_a, timeout_b, t;
 196                 struct timespec _ts, *ts;
 197
 198                 r = sd_bus_process(a, &m);
 199                 if (r < 0) {
 200                         log_error_errno(r, "Failed to process bus a: %m");
 201                         goto finish;
 202                 }
 203
 204                 if (m) {
 205                         r = sd_bus_send(b, m, NULL);
 206                         if (r < 0) {
 207                                 log_error_errno(r, "Failed to send message: %m");
 208                                 goto finish;
 209                         }
 210                 }
 211
 212                 if (r > 0)
 213                         continue;
 214
 215                 r = sd_bus_process(b, &m);
 216                 if (r < 0) {
 217                         /* treat 'connection reset by peer' as clean exit condition */
 218                         if (r == -ECONNRESET)
 219                                 r = 0;
 220
 221                         goto finish;
 222                 }
 223
 224                 if (m) {
 225                         r = sd_bus_send(a, m, NULL);
 226                         if (r < 0) {
 227                                 log_error_errno(r, "Failed to send message: %m");
 228                                 goto finish;
 229                         }
 230                 }
 231
 232                 if (r > 0)
 233                         continue;
 234
 235                 fd = sd_bus_get_fd(a);
 236                 if (fd < 0) {
 237                         r = fd;
 238                         log_error_errno(r, "Failed to get fd: %m");
 239                         goto finish;
 240                 }
 241
 242                 events_a = sd_bus_get_events(a);
 243                 if (events_a < 0) {
 244                         r = events_a;
 245                         log_error_errno(r, "Failed to get events mask: %m");
 246                         goto finish;
 247                 }
 248
 249                 r = sd_bus_get_timeout(a, &timeout_a);
 250                 if (r < 0) {
 251                         log_error_errno(r, "Failed to get timeout: %m");
 252                         goto finish;
 253                 }
 254
 255                 events_b = sd_bus_get_events(b);
 256                 if (events_b < 0) {
 257                         r = events_b;
 258                         log_error_errno(r, "Failed to get events mask: %m");
 259                         goto finish;
 260                 }
 261
 262                 r = sd_bus_get_timeout(b, &timeout_b);
 263                 if (r < 0) {
 264                         log_error_errno(r, "Failed to get timeout: %m");
 265                         goto finish;
 266                 }
 267
 268                 t = timeout_a;
 269                 if (t == (uint64_t) -1 || (timeout_b != (uint64_t) -1 && timeout_b < timeout_a))
 270                         t = timeout_b;
 271
 272                 if (t == (uint64_t) -1)
 273                         ts = NULL;
 274                 else {
 275                         usec_t nw;
 276
 277                         nw = now(CLOCK_MONOTONIC);
 278                         if (t > nw)
 279                                 t -= nw;
 280                         else
 281                                 t = 0;
 282
 283                         ts = timespec_store(&_ts, t);
 284                 }
 285
 286                 {
 287                         struct pollfd p[3] = {
 288                                 {.fd = fd,            .events = events_a, },
 289                                 {.fd = STDIN_FILENO,  .events = events_b & POLLIN, },
 290                                 {.fd = STDOUT_FILENO, .events = events_b & POLLOUT, }};
 291
 292                         r = ppoll(p, ELEMENTSOF(p), ts, NULL);
 293                 }
 294                 if (r < 0) {
 295                         log_error_errno(errno, "ppoll() failed: %m");
 296                         goto finish;
 297                 }
 298         }
 299
 300 finish:
 301         return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 302 }