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/*
* virinitctl.c: API for talking to init systems via initctl
*
* Copyright (C) 2012-2014 Red Hat, Inc.
*
* This library 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.
*
* This library 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <sys/param.h>
#include <fcntl.h>
#include "internal.h"
#include "virinitctl.h"
#include "virerror.h"
#include "virfile.h"
#define VIR_FROM_THIS VIR_FROM_INITCTL
#if defined(__linux__) || \
(defined(__FreeBSD_kernel__) && !(defined(__FreeBSD__)))
/* These constants & struct definitions are taken from
* systemd, under terms of LGPLv2+
*
* initreq.h Interface to talk to init through /dev/initctl.
*
* Copyright (C) 1995-2004 Miquel van Smoorenburg
*/
# define VIR_INITCTL_MAGIC 0x03091969
# define VIR_INITCTL_CMD_START 0
# define VIR_INITCTL_CMD_RUNLVL 1
# define VIR_INITCTL_CMD_POWERFAIL 2
# define VIR_INITCTL_CMD_POWERFAILNOW 3
# define VIR_INITCTL_CMD_POWEROK 4
# define VIR_INITCTL_CMD_BSD 5
# define VIR_INITCTL_CMD_SETENV 6
# define VIR_INITCTL_CMD_UNSETENV 7
# define VIR_INITCTL_CMD_CHANGECONS 12345
# ifdef MAXHOSTNAMELEN
# define VIR_INITCTL_RQ_HLEN MAXHOSTNAMELEN
# else
# define VIR_INITCTL_RQ_HLEN 64
# endif
/*
* This is what BSD 4.4 uses when talking to init.
* Linux doesn't use this right now.
*/
struct virInitctlRequestBSD {
char gen_id[8]; /* Beats me.. telnetd uses "fe" */
char tty_id[16]; /* Tty name minus /dev/tty */
char host[VIR_INITCTL_RQ_HLEN]; /* Hostname */
char term_type[16]; /* Terminal type */
int signal; /* Signal to send */
int pid_value; /* Process to send to */
char exec_name[128]; /* Program to execute */
char reserved[128]; /* For future expansion. */
};
/*
* Because of legacy interfaces, "runlevel" and "sleeptime"
* aren't in a separate struct in the union.
*
* The weird sizes are because init expects the whole
* struct to be 384 bytes.
*/
struct virInitctlRequest {
int magic; /* Magic number */
int cmd; /* What kind of request */
int runlevel; /* Runlevel to change to */
int sleeptime; /* Time between TERM and KILL */
union {
struct virInitctlRequestBSD bsd;
char data[368];
} i;
};
# ifdef MAXHOSTNAMELEN
G_STATIC_ASSERT(sizeof(struct virInitctlRequest) == 320 + MAXHOSTNAMELEN);
# else
G_STATIC_ASSERT(sizeof(struct virInitctlRequest) == 384);
# endif
/* List of fifos that inits are known to listen on */
const char *virInitctlFifos[] = {
"/run/initctl",
"/dev/initctl",
"/etc/.initctl",
NULL
};
/**
* virInitctlSetRunLevel:
* @fifo: the path to fifo that init listens on (can be NULL for autodetection)
* @level: the desired runlevel
*
* Send a message to init to change the runlevel. This function is
* asynchronous-signal-safe (thus safe to use after fork of a
* multithreaded parent) - which is good, because it should only be
* used after forking and entering correct namespace.
*
* Returns 1 on success, 0 if initctl does not exist, -1 on error
*/
int
virInitctlSetRunLevel(const char *fifo,
virInitctlRunLevel level)
{
struct virInitctlRequest req;
int fd = -1;
int ret = -1;
const int open_flags = O_WRONLY|O_NONBLOCK|O_CLOEXEC|O_NOCTTY;
size_t i = 0;
memset(&req, 0, sizeof(req));
req.magic = VIR_INITCTL_MAGIC;
req.sleeptime = 0;
req.cmd = VIR_INITCTL_CMD_RUNLVL;
/* Yes it is an 'int' field, but wants a numeric character. Go figure */
req.runlevel = '0' + level;
if (fifo) {
if ((fd = open(fifo, open_flags)) < 0) {
virReportSystemError(errno,
_("Cannot open init control %1$s"),
fifo);
goto cleanup;
}
} else {
for (i = 0; virInitctlFifos[i]; i++) {
fifo = virInitctlFifos[i];
if ((fd = open(fifo, open_flags)) >= 0)
break;
if (errno != ENOENT) {
virReportSystemError(errno,
_("Cannot open init control %1$s"),
fifo);
goto cleanup;
}
}
/* Ensure we found a valid initctl fifo */
if (fd < 0) {
ret = 0;
goto cleanup;
}
}
if (safewrite(fd, &req, sizeof(req)) != sizeof(req)) {
virReportSystemError(errno,
_("Failed to send request to init control %1$s"),
fifo);
goto cleanup;
}
ret = 1;
cleanup:
VIR_FORCE_CLOSE(fd);
return ret;
}
#else
/* On non-Linux and non-BSD there are no known inits */
const char *virInitctlFifos[] = {
NULL
};
int virInitctlSetRunLevel(const char *fifo G_GNUC_UNUSED,
virInitctlRunLevel level G_GNUC_UNUSED)
{
virReportUnsupportedError();
return -1;
}
#endif
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