tmux/compat/systemd.c
Nicholas Marriott b9524f5b72 Add support for spawning panes in separate cgroups with systemd and a configure
flag to disable. From Eric T Johnson yut23 AT gvljohnsons DOT com in GitHub
issue 3514.
2023-04-03 08:54:06 +01:00

216 lines
5.4 KiB
C

/* $OpenBSD$ */
/*
* Copyright (c) 2022 Nicholas Marriott <nicholas.marriott@gmail.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/un.h>
#include <systemd/sd-bus.h>
#include <systemd/sd-daemon.h>
#include <systemd/sd-login.h>
#include <systemd/sd-id128.h>
#include <string.h>
#include "tmux.h"
int
systemd_activated(void)
{
return (sd_listen_fds(0) >= 1);
}
int
systemd_create_socket(int flags, char **cause)
{
int fds;
int fd;
struct sockaddr_un sa;
socklen_t addrlen = sizeof sa;
fds = sd_listen_fds(0);
if (fds > 1) { /* too many file descriptors */
errno = E2BIG;
goto fail;
}
if (fds == 1) { /* socket-activated */
fd = SD_LISTEN_FDS_START;
if (!sd_is_socket_unix(fd, SOCK_STREAM, 1, NULL, 0)) {
errno = EPFNOSUPPORT;
goto fail;
}
if (getsockname(fd, (struct sockaddr *)&sa, &addrlen) == -1)
goto fail;
socket_path = xstrdup(sa.sun_path);
return (fd);
}
return (server_create_socket(flags, cause));
fail:
if (cause != NULL)
xasprintf(cause, "systemd socket error (%s)", strerror(errno));
return (-1);
}
int
systemd_move_pid_to_new_cgroup(pid_t pid, char **cause)
{
sd_bus_error error = SD_BUS_ERROR_NULL;
sd_bus_message *m = NULL, *reply = NULL;
sd_bus *bus = NULL;
char *name, *desc, *slice;
sd_id128_t uuid;
int r;
pid_t parent_pid;
/* Connect to the session bus. */
r = sd_bus_default_user(&bus);
if (r < 0) {
xasprintf(cause, "failed to connect to session bus: %s",
strerror(-r));
goto finish;
}
/* Start building the method call. */
r = sd_bus_message_new_method_call(bus, &m,
"org.freedesktop.systemd1",
"/org/freedesktop/systemd1",
"org.freedesktop.systemd1.Manager",
"StartTransientUnit");
if (r < 0) {
xasprintf(cause, "failed to create bus message: %s",
strerror(-r));
goto finish;
}
/* Generate a unique name for the new scope, to avoid collisions. */
r = sd_id128_randomize(&uuid);
if (r < 0) {
xasprintf(cause, "failed to generate uuid: %s", strerror(-r));
goto finish;
}
xasprintf(&name, "tmux-spawn-" SD_ID128_UUID_FORMAT_STR ".scope",
SD_ID128_FORMAT_VAL(uuid));
r = sd_bus_message_append(m, "s", name);
free(name);
if (r < 0) {
xasprintf(cause, "failed to append to bus message: %s",
strerror(-r));
goto finish;
}
/* Mode: fail if there's a queued unit with the same name. */
r = sd_bus_message_append(m, "s", "fail");
if (r < 0) {
xasprintf(cause, "failed to append to bus message: %s",
strerror(-r));
goto finish;
}
/* Start properties array. */
r = sd_bus_message_open_container(m, 'a', "(sv)");
if (r < 0) {
xasprintf(cause, "failed to start properties array: %s",
strerror(-r));
goto finish;
}
parent_pid = getpid();
xasprintf(&desc, "tmux child pane %ld launched by process %ld",
(long)pid, (long)parent_pid);
r = sd_bus_message_append(m, "(sv)", "Description", "s", desc);
free(desc);
if (r < 0) {
xasprintf(cause, "failed to append to properties: %s",
strerror(-r));
goto finish;
}
/*
* Inherit the slice from the parent process, or default to
* "app-tmux.slice" if that fails.
*/
r = sd_pid_get_user_slice(parent_pid, &slice);
if (r < 0) {
slice = xstrdup("app-tmux.slice");
}
r = sd_bus_message_append(m, "(sv)", "Slice", "s", slice);
free(slice);
if (r < 0) {
xasprintf(cause, "failed to append to properties: %s",
strerror(-r));
goto finish;
}
/* PIDs to add to the scope: length - 1 array of uint32_t. */
r = sd_bus_message_append(m, "(sv)", "PIDs", "au", 1, pid);
if (r < 0) {
xasprintf(cause, "failed to append to properties: %s",
strerror(-r));
goto finish;
}
/* Clean up the scope even if it fails. */
r = sd_bus_message_append(m, "(sv)", "CollectMode", "s",
"inactive-or-failed");
if (r < 0) {
xasprintf(cause, "failed to append to properties: %s",
strerror(-r));
goto finish;
}
/* End properties array. */
r = sd_bus_message_close_container(m);
if (r < 0) {
xasprintf(cause, "failed to end properties array: %s",
strerror(-r));
goto finish;
}
/* aux is currently unused and should be passed an empty array. */
r = sd_bus_message_append(m, "a(sa(sv))", 0);
if (r < 0) {
xasprintf(cause, "failed to append to bus message: %s",
strerror(-r));
goto finish;
}
/* Call the method with a timeout of 1 second = 1e6 us. */
r = sd_bus_call(bus, m, 1000000, &error, &reply);
if (r < 0) {
if (error.message != NULL) {
/* We have a specific error message from sd-bus. */
xasprintf(cause, "StartTransientUnit call failed: %s",
error.message);
} else {
xasprintf(cause, "StartTransientUnit call failed: %s",
strerror(-r));
}
goto finish;
}
finish:
sd_bus_error_free(&error);
sd_bus_message_unref(m);
sd_bus_message_unref(reply);
sd_bus_unref(bus);
return (r);
}