Systemd/src/machine/operation.c
Lennart Poettering 5659958529 machined: run clone operation asynchronously in the background
Cloning an image can be slow, if the image is not on a btrfs subvolume, hence
let's make sure we do this asynchronously in a child process, so that machined
isn't blocked as long as we process the client request.

This adds a new, generic "Operation" object to machined, that is used to track
these kind of background processes.

This is inspired by the MachineOperation object that already exists to make
copy operations asynchronous. A later patch will rework the MachineOperation
logic to use the generic Operation instead.
2016-05-02 11:15:30 +02:00

119 lines
3.3 KiB
C

/***
This file is part of systemd.
Copyright 2016 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "alloc-util.h"
#include "fd-util.h"
#include "operation.h"
#include "process-util.h"
static int operation_done(sd_event_source *s, const siginfo_t *si, void *userdata) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
Operation *o = userdata;
int r;
assert(o);
assert(si);
log_debug("Operating " PID_FMT " is now complete with with code=%s status=%i",
o->pid,
sigchld_code_to_string(si->si_code), si->si_status);
o->pid = 0;
if (si->si_code != CLD_EXITED) {
r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child died abnormally.");
goto fail;
}
if (si->si_status != EXIT_SUCCESS) {
if (read(o->errno_fd, &r, sizeof(r)) == sizeof(r))
r = sd_bus_error_set_errnof(&error, r, "%m");
else
r = sd_bus_error_setf(&error, SD_BUS_ERROR_FAILED, "Child failed.");
goto fail;
}
r = sd_bus_reply_method_return(o->message, NULL);
if (r < 0)
log_error_errno(r, "Failed to reply to message: %m");
operation_free(o);
return 0;
fail:
r = sd_bus_reply_method_error(o->message, &error);
if (r < 0)
log_error_errno(r, "Failed to reply to message: %m");
operation_free(o);
return 0;
}
int operation_new(Manager *m, pid_t child, sd_bus_message *message, int errno_fd) {
Operation *o;
int r;
o = new0(Operation, 1);
if (!o)
return -ENOMEM;
r = sd_event_add_child(m->event, &o->event_source, child, WEXITED, operation_done, o);
if (r < 0) {
free(o);
return r;
}
o->pid = child;
o->message = sd_bus_message_ref(message);
o->errno_fd = errno_fd;
LIST_PREPEND(operations, m->operations, o);
m->n_operations++;
o->manager = m;
log_debug("Started new operation " PID_FMT ".", child);
/* At this point we took ownership of both the child and the errno file descriptor! */
return 0;
}
Operation *operation_free(Operation *o) {
if (!o)
return NULL;
sd_event_source_unref(o->event_source);
safe_close(o->errno_fd);
if (o->pid > 1)
(void) sigkill_wait(&o->pid);
sd_bus_message_unref(o->message);
if (o->manager) {
LIST_REMOVE(operations, o->manager->operations, o);
o->manager->n_operations--;
}
free(o);
return NULL;
}