freebsd/usr.sbin/bhyve/ipc.c

/*
 * Copyright (c) 2016 Flavius Anton
 * Copyright (c) 2016 Mihai Tiganus
 * Copyright (c) 2016-2019 Mihai Carabas
 * Copyright (c) 2017-2019 Darius Mihai
 * Copyright (c) 2017-2019 Elena Mihailescu
 * Copyright (c) 2018-2019 Sergiu Weisz
 * Copyright (c) 2025 Bojan Novković <[email protected]>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "ipc.h"

#ifndef WITHOUT_CAPSICUM
#include <sys/capsicum.h>
#endif
#include <sys/types.h>
#include <sys/linker_set.h>
#include <sys/socket.h>
#include <sys/un.h>

#ifndef WITHOUT_CAPSICUM
#include <capsicum_helpers.h>
#endif
#include <sys/cpuset.h>
#include <sys/ioctl.h>

#include <machine/vmm.h>
#include <machine/vmm_snapshot.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <pthread.h>
#include <pthread_np.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include <vmmapi.h>

#include "bhyverun.h"
#include "debug.h"

#define IPC_COMMAND_FOREACH(pvar, set) SET_FOREACH(pvar, set)

SET_DECLARE(ipc_cmd_set, struct ipc_command);

static struct ipc_thread_ctx {
	struct vmctx *vmctx;
	int sockfd;
} thr_ctx;

static nvlist_t *
ipc_get_vm_pid(struct vmctx *ctx __unused, const nvlist_t *nvl __unused)
{
	nvlist_t *reply;

	reply = nvlist_create(0);
	nvlist_add_number(reply, "pid", getpid());
	return (reply);
}
IPC_COMMAND(get_vm_pid, ipc_get_vm_pid);

static nvlist_t *
handle_message(struct vmctx *ctx, nvlist_t *nvl)
{
	const char *cmd;
	struct ipc_command **ipc_cmd;

	cmd = nvlist_get_string(nvl, "cmd");
	IPC_COMMAND_FOREACH(ipc_cmd, ipc_cmd_set)
	{
		if (strcmp(cmd, (*ipc_cmd)->name) == 0)
			return ((*ipc_cmd)->handler(ctx, nvl));
	}

	return (NULL);
}

/*
 * Listen for commands from bhyvectl.
 */
static void *
ipc_thread(void *param)
{
	int fd;
	nvlist_t *nvl, *reply;
	const char *cmdname;
	struct ipc_thread_ctx *ctx;

	pthread_set_name_np(pthread_self(), "IPC thread");
	ctx = (struct ipc_thread_ctx *)param;
	while ((fd = accept(ctx->sockfd, NULL, NULL)) != -1) {
		nvl = nvlist_recv(fd, 0);
		if (nvl == NULL) {
			EPRINTLN("%s: nvlist_recv() failed: %s", __func__,
			    strerror(errno));
			close(fd);
			continue;
		}

		cmdname = nvlist_get_string(nvl, "cmd");
		if (cmdname == NULL) {
			nvlist_add_string(nvl, "error", "missing command name");
			nvlist_send(fd, nvl);
			nvlist_destroy(nvl);
			close(fd);
			continue;
		}
		reply = handle_message(ctx->vmctx, nvl);
		if (reply == NULL) {
			reply = nvlist_create(0);
			nvlist_add_stringf(reply, "error", "command '%s' not found",
			    cmdname);
		}
		/* The handler should set the error message if need be. */
		nvlist_send(fd, reply);

		nvlist_destroy(nvl);
		nvlist_destroy(reply);
		close(fd);
	}

	return (NULL);
}

/*
 * Create the listening socket for IPC with bhyvectl.
 */
int
init_ipc_thread(struct vmctx *ctx, const char *bhyve_run_dir)
{
	struct sockaddr_un addr;
	pthread_t ipc_pthread;
	int socket_fd;
	int err, ret;
#ifndef WITHOUT_CAPSICUM
	cap_rights_t rights;
#endif

	memset(&addr, 0, sizeof(addr));

	socket_fd = socket(PF_UNIX, SOCK_STREAM, 0);
	if (socket_fd < 0) {
		EPRINTLN("Socket creation failed: %s", strerror(errno));
		err = -1;
		goto fail;
	}

	addr.sun_family = AF_UNIX;

	ret = snprintf(addr.sun_path, sizeof(addr.sun_path), "%s/%s",
	    bhyve_run_dir, vm_get_name(ctx));
	if ((ret < 0) || ((size_t)ret >= sizeof(addr.sun_path))) {
		EPRINTLN("%s: error setting socket path (%d)", __func__, ret);
		err = -1;
		goto fail;
	}

	addr.sun_len = SUN_LEN(&addr);
	unlink(addr.sun_path);

	if (bind(socket_fd, (struct sockaddr *)&addr, addr.sun_len) != 0) {
		EPRINTLN("Failed to bind socket \"%s\": %s\n",
		    addr.sun_path, strerror(errno));
		err = -1;
		goto fail;
	}

	if (listen(socket_fd, 10) < 0) {
		EPRINTLN("ipc socket listen: %s\n", strerror(errno));
		err = errno;
		goto fail;
	}

#ifndef WITHOUT_CAPSICUM
	cap_rights_init(&rights, CAP_ACCEPT, CAP_READ, CAP_RECV, CAP_WRITE,
	    CAP_SEND, CAP_GETSOCKOPT);

	if (caph_rights_limit(socket_fd, &rights) == -1)
		errx(EX_OSERR, "Unable to apply rights for sandbox");
#endif
	memset(&thr_ctx, 0, sizeof(thr_ctx));
	thr_ctx.vmctx = ctx;
	thr_ctx.sockfd = socket_fd;

	err = pthread_create(&ipc_pthread, NULL, ipc_thread,
		&thr_ctx);
	if (err != 0)
		goto fail;

	return (0);
fail:
	if (socket_fd > 0)
		close(socket_fd);
	unlink(addr.sun_path);

	return (err);
}