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mirror of git://git.proxmox.com/git/qemu-server.git synced 2024-12-22 13:34:06 +03:00
qemu-server/qmeventd/qmeventd.c
Thomas Lamprecht 8752e5a3ec move qmeventd to own directory
It's really not nice if such many files, source code, meta-files, …
linger around in the top level directory..

Also, cleanup the build a bit, i.e., use LDFLAGS as dpkg-buildpackage
can set some LDFLAGS so it'd be nice if both CFLAFGS and LDFLAGS have
the same (related) ones.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
2019-09-24 18:57:54 +02:00

430 lines
10 KiB
C

/*
Copyright (C) 2018 Proxmox Server Solutions GmbH
Copyright: qmeventd is under GNU GPL, the GNU General Public License.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 dated June, 1991.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.
Author: Dominik Csapak <d.csapak@proxmox.com>
qmeventd listens on a given socket, and waits for qemu processes
to connect
it then waits for shutdown events followed by the closing of the socket,
it then calls /usr/sbin/qm cleanup with following arguments
/usr/sbin/qm cleanup VMID <graceful> <guest>
parameter explanation:
graceful:
1|0 depending if it saw a shutdown event before the socket closed
guest:
1|0 depending if the shutdown was requested from the guest
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <errno.h>
#include <fcntl.h>
#include <json.h>
#include <signal.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <sys/epoll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include <sys/wait.h>
#include <unistd.h>
#include "qmeventd.h"
static int verbose = 0;
static int epoll_fd = 0;
static const char *progname;
/*
* Helper functions
*/
static void
usage()
{
fprintf(stderr, "Usage: %s [-f] [-v] PATH\n", progname);
fprintf(stderr, " -f run in foreground (default: false)\n");
fprintf(stderr, " -v verbose (default: false)\n");
fprintf(stderr, " PATH use PATH for socket\n");
}
static pid_t
get_pid_from_fd(int fd)
{
struct ucred credentials = { .pid = 0, .uid = 0, .gid = 0 };
socklen_t len = sizeof(struct ucred);
log_neg(getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &credentials, &len), "getsockopt");
return credentials.pid;
}
/*
* reads the vmid from /proc/<pid>/cmdline
* after the '-id' argument
*/
static unsigned long
get_vmid_from_pid(pid_t pid)
{
char filename[32] = { 0 };
int len = snprintf(filename, sizeof(filename), "/proc/%d/cmdline", pid);
if (len < 0) {
fprintf(stderr, "error during snprintf for %d: %s\n", pid,
strerror(errno));
return 0;
}
if ((size_t)len >= sizeof(filename)) {
fprintf(stderr, "error: pid %d too long\n", pid);
return 0;
}
FILE *fp = fopen(filename, "re");
if (fp == NULL) {
fprintf(stderr, "error opening %s: %s\n", filename, strerror(errno));
return 0;
}
unsigned long vmid = 0;
ssize_t rc = 0;
char *buf = NULL;
size_t buflen = 0;
while ((rc = getdelim(&buf, &buflen, '\0', fp)) >= 0) {
if (!strcmp(buf, "-id")) {
break;
}
}
if (rc < 0) {
goto err;
}
if (getdelim(&buf, &buflen, '\0', fp) >= 0) {
if (buf[0] == '-' || buf[0] == '\0') {
fprintf(stderr, "invalid vmid %s\n", buf);
goto ret;
}
errno = 0;
char *endptr = NULL;
vmid = strtoul(buf, &endptr, 10);
if (errno != 0) {
vmid = 0;
goto err;
} else if (*endptr != '\0') {
fprintf(stderr, "invalid vmid %s\n", buf);
vmid = 0;
}
goto ret;
}
err:
fprintf(stderr, "error parsing vmid for %d: %s\n", pid, strerror(errno));
ret:
free(buf);
fclose(fp);
return vmid;
}
static bool
must_write(int fd, const char *buf, size_t len)
{
ssize_t wlen;
do {
wlen = write(fd, buf, len);
} while (wlen < 0 && errno == EINTR);
return (wlen == (ssize_t)len);
}
/*
* qmp handling functions
*/
void
handle_qmp_handshake(struct Client *client)
{
VERBOSE_PRINT("%s: got QMP handshake\n", client->vmid);
static const char qmp_answer[] = "{\"execute\":\"qmp_capabilities\"}\n";
if (!must_write(client->fd, qmp_answer, sizeof(qmp_answer) - 1)) {
fprintf(stderr, "%s: cannot complete handshake\n", client->vmid);
cleanup_client(client);
}
}
void
handle_qmp_event(struct Client *client, struct json_object *obj)
{
struct json_object *event;
if (!json_object_object_get_ex(obj, "event", &event)) {
return;
}
VERBOSE_PRINT("%s: got QMP event: %s\n", client->vmid,
json_object_get_string(event));
// event, check if shutdown and get guest parameter
if (!strcmp(json_object_get_string(event), "SHUTDOWN")) {
client->graceful = 1;
struct json_object *data;
struct json_object *guest;
if (json_object_object_get_ex(obj, "data", &data) &&
json_object_object_get_ex(data, "guest", &guest))
{
client->guest = (unsigned short)json_object_get_boolean(guest);
}
}
}
/*
* client management functions
*/
void
add_new_client(int client_fd)
{
struct Client *client = calloc(sizeof(struct Client), 1);
client->fd = client_fd;
client->pid = get_pid_from_fd(client_fd);
if (client->pid == 0) {
fprintf(stderr, "could not get pid from client\n");
goto err;
}
unsigned long vmid = get_vmid_from_pid(client->pid);
int res = snprintf(client->vmid, sizeof(client->vmid), "%lu", vmid);
if (vmid == 0 || res < 0 || res >= (int)sizeof(client->vmid)) {
fprintf(stderr, "could not get vmid from pid %d\n", client->pid);
goto err;
}
struct epoll_event ev;
ev.events = EPOLLIN;
ev.data.ptr = client;
res = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, client_fd, &ev);
if (res < 0) {
perror("epoll_ctl client add");
goto err;
}
VERBOSE_PRINT("added new client, pid: %d, vmid: %s\n", client->pid,
client->vmid);
return;
err:
(void)close(client_fd);
free(client);
}
void
cleanup_client(struct Client *client)
{
VERBOSE_PRINT("%s: client exited, status: graceful: %d, guest: %d\n",
client->vmid, client->graceful, client->guest);
log_neg(epoll_ctl(epoll_fd, EPOLL_CTL_DEL, client->fd, NULL), "epoll del");
(void)close(client->fd);
unsigned short graceful = client->graceful;
unsigned short guest = client->guest;
char vmid[sizeof(client->vmid)];
strncpy(vmid, client->vmid, sizeof(vmid));
free(client);
VERBOSE_PRINT("%s: executing cleanup\n", vmid);
int pid = fork();
if (pid < 0) {
fprintf(stderr, "fork failed: %s\n", strerror(errno));
return;
}
if (pid == 0) {
char *script = "/usr/sbin/qm";
char *args[] = {
script,
"cleanup",
vmid,
graceful ? "1" : "0",
guest ? "1" : "0",
NULL
};
execvp(script, args);
perror("execvp");
_exit(1);
}
}
void
handle_client(struct Client *client)
{
VERBOSE_PRINT("%s: entering handle\n", client->vmid);
ssize_t len;
do {
len = read(client->fd, (client->buf+client->buflen),
sizeof(client->buf) - client->buflen);
} while (len < 0 && errno == EINTR);
if (len < 0) {
if (!(errno == EAGAIN || errno == EWOULDBLOCK)) {
log_neg((int)len, "read");
cleanup_client(client);
}
return;
} else if (len == 0) {
VERBOSE_PRINT("%s: got EOF\n", client->vmid);
cleanup_client(client);
return;
}
VERBOSE_PRINT("%s: read %ld bytes\n", client->vmid, len);
client->buflen += len;
struct json_tokener *tok = json_tokener_new();
struct json_object *jobj = NULL;
enum json_tokener_error jerr = json_tokener_success;
while (jerr == json_tokener_success && client->buflen != 0) {
jobj = json_tokener_parse_ex(tok, client->buf, (int)client->buflen);
jerr = json_tokener_get_error(tok);
unsigned int offset = (unsigned int)tok->char_offset;
switch (jerr) {
case json_tokener_success:
// move rest from buffer to front
memmove(client->buf, client->buf + offset, client->buflen - offset);
client->buflen -= offset;
if (json_object_is_type(jobj, json_type_object)) {
struct json_object *obj;
if (json_object_object_get_ex(jobj, "QMP", &obj)) {
handle_qmp_handshake(client);
} else if (json_object_object_get_ex(jobj, "event", &obj)) {
handle_qmp_event(client, jobj);
} // else ignore message
}
break;
case json_tokener_continue:
if (client->buflen >= sizeof(client->buf)) {
VERBOSE_PRINT("%s, msg too large, discarding buffer\n",
client->vmid);
memset(client->buf, 0, sizeof(client->buf));
client->buflen = 0;
} // else we have enough space try again after next read
break;
default:
VERBOSE_PRINT("%s: parse error: %d, discarding buffer\n",
client->vmid, jerr);
memset(client->buf, 0, client->buflen);
client->buflen = 0;
break;
}
json_object_put(jobj);
}
json_tokener_free(tok);
}
int
main(int argc, char *argv[])
{
int opt;
int daemonize = 1;
char *socket_path = NULL;
progname = argv[0];
while ((opt = getopt(argc, argv, "hfv")) != -1) {
switch (opt) {
case 'f':
daemonize = 0;
break;
case 'v':
verbose = 1;
break;
case 'h':
usage();
exit(EXIT_SUCCESS);
break;
default:
usage();
exit(EXIT_FAILURE);
}
}
if (optind >= argc) {
usage();
exit(EXIT_FAILURE);
}
signal(SIGCHLD, SIG_IGN);
socket_path = argv[optind];
int sock = socket(AF_UNIX, SOCK_STREAM, 0);
bail_neg(sock, "socket");
struct sockaddr_un addr;
memset(&addr, 0, sizeof(addr));
addr.sun_family = AF_UNIX;
strncpy(addr.sun_path, socket_path, sizeof(addr.sun_path) - 1);
unlink(socket_path);
bail_neg(bind(sock, (struct sockaddr*)&addr, sizeof(addr)), "bind");
struct epoll_event ev, events[1];
epoll_fd = epoll_create1(EPOLL_CLOEXEC);
bail_neg(epoll_fd, "epoll_create1");
ev.events = EPOLLIN;
ev.data.fd = sock;
bail_neg(epoll_ctl(epoll_fd, EPOLL_CTL_ADD, sock, &ev), "epoll_ctl");
bail_neg(listen(sock, 10), "listen");
if (daemonize) {
bail_neg(daemon(0, 1), "daemon");
}
int nevents;
for(;;) {
nevents = epoll_wait(epoll_fd, events, 1, -1);
if (nevents < 0 && errno == EINTR) {
// signal happened, try again
continue;
}
bail_neg(nevents, "epoll_wait");
for (int n = 0; n < nevents; n++) {
if (events[n].data.fd == sock) {
int conn_sock = accept4(sock, NULL, NULL,
SOCK_NONBLOCK | SOCK_CLOEXEC);
log_neg(conn_sock, "accept");
if (conn_sock > -1) {
add_new_client(conn_sock);
}
} else {
handle_client((struct Client *)events[n].data.ptr);
}
}
}
}