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 <string.h>
  28
  29 #include "tmux.h"
  30
  31 int
  32 systemd_activated(void)
  33 {
  34         return (sd_listen_fds(0) >= 1);
  35 }
  36
  37 int
  38 systemd_create_socket(int flags, char **cause)
  39 {
  40         int                     fds;
  41         int                     fd;
  42         struct sockaddr_un      sa;
  43         socklen_t               addrlen = sizeof sa;
  44
  45         fds = sd_listen_fds(0);
  46         if (fds > 1) { /* too many file descriptors */
  47                 errno = E2BIG;
  48                 goto fail;
  49         }
  50
  51         if (fds == 1) { /* socket-activated */
  52                 fd = SD_LISTEN_FDS_START;
  53                 if (!sd_is_socket_unix(fd, SOCK_STREAM, 1, NULL, 0)) {
  54                         errno = EPFNOSUPPORT;
  55                         goto fail;
  56                 }
  57                 if (getsockname(fd, (struct sockaddr *)&sa, &addrlen) == -1)
  58                         goto fail;
  59                 socket_path = xstrdup(sa.sun_path);
  60                 return (fd);
  61         }
  62
  63         return (server_create_socket(flags, cause));
  64
  65 fail:
  66         if (cause != NULL)
  67                 xasprintf(cause, "systemd socket error (%s)", strerror(errno));
  68         return (-1);
  69 }
  70
  71 int
  72 systemd_move_pid_to_new_cgroup(pid_t pid, char **cause)
  73 {
  74         sd_bus_error     error = SD_BUS_ERROR_NULL;
  75         sd_bus_message  *m = NULL, *reply = NULL;
  76         sd_bus          *bus = NULL;
  77         char            *name, *desc, *slice;
  78         sd_id128_t       uuid;
  79         int              r;
  80         pid_t            parent_pid;
  81
  82         /* Connect to the session bus. */
  83         r = sd_bus_default_user(&bus);
  84         if (r < 0) {
  85                 xasprintf(cause, "failed to connect to session bus: %s",
  86                     strerror(-r));
  87                 goto finish;
  88         }
  89
  90         /* Start building the method call. */
  91         r = sd_bus_message_new_method_call(bus, &m,
  92             "org.freedesktop.systemd1",
  93             "/org/freedesktop/systemd1",
  94             "org.freedesktop.systemd1.Manager",
  95             "StartTransientUnit");
  96         if (r < 0) {
  97                 xasprintf(cause, "failed to create bus message: %s",
  98                     strerror(-r));
  99                 goto finish;
 100         }
 101
 102         /* Generate a unique name for the new scope, to avoid collisions. */
 103         r = sd_id128_randomize(&uuid);
 104         if (r < 0) {
 105                 xasprintf(cause, "failed to generate uuid: %s", strerror(-r));
 106                 goto finish;
 107         }
 108         xasprintf(&name, "tmux-spawn-" SD_ID128_UUID_FORMAT_STR ".scope",
 109             SD_ID128_FORMAT_VAL(uuid));
 110         r = sd_bus_message_append(m, "s", name);
 111         free(name);
 112         if (r < 0) {
 113                 xasprintf(cause, "failed to append to bus message: %s",
 114                     strerror(-r));
 115                 goto finish;
 116         }
 117
 118         /* Mode: fail if there's a queued unit with the same name. */
 119         r = sd_bus_message_append(m, "s", "fail");
 120         if (r < 0) {
 121                 xasprintf(cause, "failed to append to bus message: %s",
 122                     strerror(-r));
 123                 goto finish;
 124         }
 125
 126         /* Start properties array. */
 127         r = sd_bus_message_open_container(m, 'a', "(sv)");
 128         if (r < 0) {
 129                 xasprintf(cause, "failed to start properties array: %s",
 130                     strerror(-r));
 131                 goto finish;
 132         }
 133
 134         parent_pid = getpid();
 135         xasprintf(&desc, "tmux child pane %ld launched by process %ld",
 136             (long)pid, (long)parent_pid);
 137         r = sd_bus_message_append(m, "(sv)", "Description", "s", desc);
 138         free(desc);
 139         if (r < 0) {
 140                 xasprintf(cause, "failed to append to properties: %s",
 141                     strerror(-r));
 142                 goto finish;
 143         }
 144
 145         /*
 146          * Inherit the slice from the parent process, or default to
 147          * "app-tmux.slice" if that fails.
 148          */
 149         r = sd_pid_get_user_slice(parent_pid, &slice);
 150         if (r < 0) {
 151                 slice = xstrdup("app-tmux.slice");
 152         }
 153         r = sd_bus_message_append(m, "(sv)", "Slice", "s", slice);
 154         free(slice);
 155         if (r < 0) {
 156                 xasprintf(cause, "failed to append to properties: %s",
 157                     strerror(-r));
 158                 goto finish;
 159         }
 160
 161         /* PIDs to add to the scope: length - 1 array of uint32_t. */
 162         r = sd_bus_message_append(m, "(sv)", "PIDs", "au", 1, pid);
 163         if (r < 0) {
 164                 xasprintf(cause, "failed to append to properties: %s",
 165                     strerror(-r));
 166                 goto finish;
 167         }
 168
 169         /* Clean up the scope even if it fails. */
 170         r = sd_bus_message_append(m, "(sv)", "CollectMode", "s",
 171             "inactive-or-failed");
 172         if (r < 0) {
 173                 xasprintf(cause, "failed to append to properties: %s",
 174                     strerror(-r));
 175                 goto finish;
 176         }
 177
 178         /* End properties array. */
 179         r = sd_bus_message_close_container(m);
 180         if (r < 0) {
 181                 xasprintf(cause, "failed to end properties array: %s",
 182                     strerror(-r));
 183                 goto finish;
 184         }
 185
 186         /* aux is currently unused and should be passed an empty array. */
 187         r = sd_bus_message_append(m, "a(sa(sv))", 0);
 188         if (r < 0) {
 189                 xasprintf(cause, "failed to append to bus message: %s",
 190                     strerror(-r));
 191                 goto finish;
 192         }
 193
 194         /* Call the method with a timeout of 1 second = 1e6 us. */
 195         r = sd_bus_call(bus, m, 1000000, &error, &reply);
 196         if (r < 0) {
 197                 if (error.message != NULL) {
 198                         /* We have a specific error message from sd-bus. */
 199                         xasprintf(cause, "StartTransientUnit call failed: %s",
 200                             error.message);
 201                 } else {
 202                         xasprintf(cause, "StartTransientUnit call failed: %s",
 203                             strerror(-r));
 204                 }
 205                 goto finish;
 206         }
 207
 208 finish:
 209         sd_bus_error_free(&error);
 210         sd_bus_message_unref(m);
 211         sd_bus_message_unref(reply);
 212         sd_bus_unref(bus);
 213
 214         return (r);
 215 }