compat/systemd.c

   1 /* $OpenBSD$ */
   2
   3 /*
   4  * Copyright (c) 2022 Nicholas Marriott <nicholas.marriott@gmail.com>
   5  *
   6  * Permission to use, copy, modify, and distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
  15  * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
  16  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <sys/types.h>
  20 #include <sys/un.h>
  21
  22 #include <systemd/sd-bus.h>
  23 #include <systemd/sd-daemon.h>
  24 #include <systemd/sd-login.h>
  25 #include <systemd/sd-id128.h>
  26
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include "tmux.h"
  32
  33 #ifndef SD_ID128_UUID_FORMAT_STR
  34 #define SD_ID128_UUID_FORMAT_STR \
  35         "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x"
  36 #endif
  37
  38 int
  39 systemd_activated(void)
  40 {
  41         return (sd_listen_fds(0) >= 1);
  42 }
  43
  44 int
  45 systemd_create_socket(int flags, char **cause)
  46 {
  47         int                     fds;
  48         int                     fd;
  49         struct sockaddr_un      sa;
  50         socklen_t               addrlen = sizeof sa;
  51
  52         fds = sd_listen_fds(0);
  53         if (fds > 1) { /* too many file descriptors */
  54                 errno = E2BIG;
  55                 goto fail;
  56         }
  57
  58         if (fds == 1) { /* socket-activated */
  59                 fd = SD_LISTEN_FDS_START;
  60                 if (!sd_is_socket_unix(fd, SOCK_STREAM, 1, NULL, 0)) {
  61                         errno = EPFNOSUPPORT;
  62                         goto fail;
  63                 }
  64                 if (getsockname(fd, (struct sockaddr *)&sa, &addrlen) == -1)
  65                         goto fail;
  66                 socket_path = xstrdup(sa.sun_path);
  67                 return (fd);
  68         }
  69
  70         return (server_create_socket(flags, cause));
  71
  72 fail:
  73         if (cause != NULL)
  74                 xasprintf(cause, "systemd socket error (%s)", strerror(errno));
  75         return (-1);
  76 }
  77
  78 int
  79 systemd_move_pid_to_new_cgroup(pid_t pid, char **cause)
  80 {
  81         sd_bus_error     error = SD_BUS_ERROR_NULL;
  82         sd_bus_message  *m = NULL, *reply = NULL;
  83         sd_bus          *bus = NULL;
  84         char            *name, *desc, *slice;
  85         sd_id128_t       uuid;
  86         int              r;
  87         pid_t            parent_pid;
  88
  89         /* Connect to the session bus. */
  90         r = sd_bus_default_user(&bus);
  91         if (r < 0) {
  92                 xasprintf(cause, "failed to connect to session bus: %s",
  93                     strerror(-r));
  94                 goto finish;
  95         }
  96
  97         /* Start building the method call. */
  98         r = sd_bus_message_new_method_call(bus, &m,
  99             "org.freedesktop.systemd1",
 100             "/org/freedesktop/systemd1",
 101             "org.freedesktop.systemd1.Manager",
 102             "StartTransientUnit");
 103         if (r < 0) {
 104                 xasprintf(cause, "failed to create bus message: %s",
 105                     strerror(-r));
 106                 goto finish;
 107         }
 108
 109         /* Generate a unique name for the new scope, to avoid collisions. */
 110         r = sd_id128_randomize(&uuid);
 111         if (r < 0) {
 112                 xasprintf(cause, "failed to generate uuid: %s", strerror(-r));
 113                 goto finish;
 114         }
 115         xasprintf(&name, "tmux-spawn-" SD_ID128_UUID_FORMAT_STR ".scope",
 116             SD_ID128_FORMAT_VAL(uuid));
 117         r = sd_bus_message_append(m, "s", name);
 118         free(name);
 119         if (r < 0) {
 120                 xasprintf(cause, "failed to append to bus message: %s",
 121                     strerror(-r));
 122                 goto finish;
 123         }
 124
 125         /* Mode: fail if there's a queued unit with the same name. */
 126         r = sd_bus_message_append(m, "s", "fail");
 127         if (r < 0) {
 128                 xasprintf(cause, "failed to append to bus message: %s",
 129                     strerror(-r));
 130                 goto finish;
 131         }
 132
 133         /* Start properties array. */
 134         r = sd_bus_message_open_container(m, 'a', "(sv)");
 135         if (r < 0) {
 136                 xasprintf(cause, "failed to start properties array: %s",
 137                     strerror(-r));
 138                 goto finish;
 139         }
 140
 141         parent_pid = getpid();
 142         xasprintf(&desc, "tmux child pane %ld launched by process %ld",
 143             (long)pid, (long)parent_pid);
 144         r = sd_bus_message_append(m, "(sv)", "Description", "s", desc);
 145         free(desc);
 146         if (r < 0) {
 147                 xasprintf(cause, "failed to append to properties: %s",
 148                     strerror(-r));
 149                 goto finish;
 150         }
 151
 152         /*
 153          * Make sure that the session shells are terminated with SIGHUP since
 154          * bash and friends tend to ignore SIGTERM.
 155          */
 156         r = sd_bus_message_append(m, "(sv)", "SendSIGHUP", "b", 1);
 157         if (r < 0) {
 158                 xasprintf(cause, "failed to append to properties: %s",
 159                     strerror(-r));
 160                 goto finish;
 161         }
 162
 163         /*
 164          * Inherit the slice from the parent process, or default to
 165          * "app-tmux.slice" if that fails.
 166          */
 167         r = sd_pid_get_user_slice(parent_pid, &slice);
 168         if (r < 0) {
 169                 slice = xstrdup("app-tmux.slice");
 170         }
 171         r = sd_bus_message_append(m, "(sv)", "Slice", "s", slice);
 172         free(slice);
 173         if (r < 0) {
 174                 xasprintf(cause, "failed to append to properties: %s",
 175                     strerror(-r));
 176                 goto finish;
 177         }
 178
 179         /* PIDs to add to the scope: length - 1 array of uint32_t. */
 180         r = sd_bus_message_append(m, "(sv)", "PIDs", "au", 1, pid);
 181         if (r < 0) {
 182                 xasprintf(cause, "failed to append to properties: %s",
 183                     strerror(-r));
 184                 goto finish;
 185         }
 186
 187         /* Clean up the scope even if it fails. */
 188         r = sd_bus_message_append(m, "(sv)", "CollectMode", "s",
 189             "inactive-or-failed");
 190         if (r < 0) {
 191                 xasprintf(cause, "failed to append to properties: %s",
 192                     strerror(-r));
 193                 goto finish;
 194         }
 195
 196         /* End properties array. */
 197         r = sd_bus_message_close_container(m);
 198         if (r < 0) {
 199                 xasprintf(cause, "failed to end properties array: %s",
 200                     strerror(-r));
 201                 goto finish;
 202         }
 203
 204         /* aux is currently unused and should be passed an empty array. */
 205         r = sd_bus_message_append(m, "a(sa(sv))", 0);
 206         if (r < 0) {
 207                 xasprintf(cause, "failed to append to bus message: %s",
 208                     strerror(-r));
 209                 goto finish;
 210         }
 211
 212         /* Call the method with a timeout of 1 second = 1e6 us. */
 213         r = sd_bus_call(bus, m, 1000000, &error, &reply);
 214         if (r < 0) {
 215                 if (error.message != NULL) {
 216                         /* We have a specific error message from sd-bus. */
 217                         xasprintf(cause, "StartTransientUnit call failed: %s",
 218                             error.message);
 219                 } else {
 220                         xasprintf(cause, "StartTransientUnit call failed: %s",
 221                             strerror(-r));
 222                 }
 223                 goto finish;
 224         }
 225
 226 finish:
 227         sd_bus_error_free(&error);
 228         sd_bus_message_unref(m);
 229         sd_bus_message_unref(reply);
 230         sd_bus_unref(bus);
 231
 232         return (r);
 233 }