/*      $OpenBSD: control.c,v 1.55 2026/07/29 13:32:18 claudio Exp $    */

/*
 * Copyright (c) 2010-2015 Reyk Floeter <reyk@openbsd.org>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
 *
 * 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 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/queue.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>

#include <errno.h>
#include <event.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "proc.h"
#include "vmd.h"

#define CONTROL_BACKLOG 5

struct ctl_connlist ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);

struct ctl_notify {
        int                     ctl_fd;
        uint32_t                ctl_vmid;
        TAILQ_ENTRY(ctl_notify) entry;
};
TAILQ_HEAD(ctl_notify_q, ctl_notify) ctl_notify_q =
        TAILQ_HEAD_INITIALIZER(ctl_notify_q);
void
         control_accept(int, short, void *);
struct ctl_conn
        *control_connbyfd(int);
void     control_close(int, struct control_sock *);
void     control_dispatch_imsg(int, short, void *);
int      control_dispatch_vmd(int, struct privsep_proc *, struct imsg *);
void     control_run(struct privsep *, struct privsep_proc *, void *);

static struct privsep_proc procs[] = {
        { "parent",     PROC_PARENT,    control_dispatch_vmd }
};

void
control(struct privsep *ps, struct privsep_proc *p)
{
        proc_run(ps, p, procs, nitems(procs), control_run, NULL);
}

void
control_run(struct privsep *ps, struct privsep_proc *p, void *arg)
{
        /*
         * pledge in the control process:
         * stdio - for malloc and basic I/O including events.
         * unix - for the control socket.
         * recvfd - for the proc fd exchange.
         * sendfd - for send and receive.
         */
        if (pledge("stdio unix recvfd sendfd", NULL) == -1)
                fatal("pledge");

        /* Signal to the parent that we're done initializing. */
        proc_compose(ps, PROC_PARENT, IMSG_VMDOP_DONE, NULL, 0);
}

int
control_dispatch_vmd(int fd, struct privsep_proc *p, struct imsg *imsg)
{
        struct ctl_conn         *c;
        struct ctl_notify       *notify = NULL, *notify_next;
        struct privsep          *ps = p->p_ps;
        struct vmop_result       vmr;
        uint32_t                 peer_id, type;
        int                      waiting = 0;
        unsigned int             mode;

        peer_id = imsg_get_id(imsg);
        type = imsg_get_type(imsg);

        switch (type) {
        case IMSG_VMDOP_START_VM_RESPONSE:
        case IMSG_VMDOP_PAUSE_VM_RESPONSE:
        case IMSG_VMDOP_UNPAUSE_VM_RESPONSE:
        case IMSG_VMDOP_GET_INFO_VM_DATA:
        case IMSG_VMDOP_GET_INFO_VM_END_DATA:
        case IMSG_CTL_FAIL:
        case IMSG_CTL_OK:
                /* Provide basic response back to a specific control client */
                if ((c = control_connbyfd(peer_id)) == NULL) {
                        log_warnx("%s: lost control connection: fd %d",
                            __func__, peer_id);
                        return (0);
                }
                imsg_forward_event(&c->iev, imsg);
                break;
        case IMSG_VMDOP_TERMINATE_VM_RESPONSE:
                vmop_result_read(imsg, &vmr);
                if ((c = control_connbyfd(peer_id)) == NULL) {
                        log_warnx("%s: lost control connection: fd %d",
                            __func__, peer_id);
                        return (0);
                }

                TAILQ_FOREACH(notify, &ctl_notify_q, entry) {
                        if (notify->ctl_fd == (int) peer_id) {
                                /*
                                 * Update if waiting by vm name. This is only
                                 * supported when stopping a single vm. If
                                 * stopping all vms, vmctl(8) sends the request
                                 * using the vmid.
                                 */
                                if (notify->ctl_vmid < 1)
                                        notify->ctl_vmid = vmr.vmr_id;
                                waiting = 1;
                                break;
                        }
                }

                /* An error needs to be relayed to the client immediately */
                if (!waiting || vmr.vmr_result) {
                        imsg_compose_event(&c->iev, type, 0, 0, -1, &vmr,
                            sizeof(vmr));

                        if (notify) {
                                TAILQ_REMOVE(&ctl_notify_q, notify, entry);
                                free(notify);
                        }
                }
                break;
        case IMSG_VMDOP_TERMINATE_VM_EVENT:
                /* Notify any waiting clients that a VM terminated */
                vmop_result_read(imsg, &vmr);

                TAILQ_FOREACH_SAFE(notify, &ctl_notify_q, entry, notify_next) {
                        if (notify->ctl_vmid != vmr.vmr_id)
                                continue;
                        if ((c = control_connbyfd(notify->ctl_fd)) != NULL) {
                                /* Forward to the vmctl(8) client */
                                imsg_compose_event(&c->iev, type, 0, 0, -1,
                                    &vmr, sizeof(vmr));
                                TAILQ_REMOVE(&ctl_notify_q, notify, entry);
                                free(notify);
                        }
                }
                break;
        case IMSG_VMDOP_CONFIG:
                config_getconfig(ps->ps_env, imsg);
                proc_compose(ps, PROC_PARENT, IMSG_VMDOP_DONE, NULL, 0);
                break;
        case IMSG_CTL_RESET:
                mode = imsg_uint_read(imsg);
                config_purge(ps->ps_env, mode);
                break;
        default:
                return (-1);
        }

        return (0);
}

int
control_init(struct privsep *ps, struct control_sock *cs)
{
        struct sockaddr_un       sun;
        int                      fd;
        mode_t                   old_umask, mode;

        if (cs->cs_name == NULL)
                return (0);

        if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0)) == -1) {
                log_warn("%s: socket", __func__);
                return (-1);
        }

        sun.sun_family = AF_UNIX;
        if (strlcpy(sun.sun_path, cs->cs_name,
            sizeof(sun.sun_path)) >= sizeof(sun.sun_path)) {
                log_warn("%s: %s name too long", __func__, cs->cs_name);
                close(fd);
                return (-1);
        }

        if (unlink(cs->cs_name) == -1)
                if (errno != ENOENT) {
                        log_warn("%s: unlink %s", __func__, cs->cs_name);
                        close(fd);
                        return (-1);
                }

        if (cs->cs_restricted) {
                old_umask = umask(S_IXUSR|S_IXGRP|S_IXOTH);
                mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
        } else {
                old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
                mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
        }

        if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
                log_warn("%s: bind: %s", __func__, cs->cs_name);
                close(fd);
                (void)umask(old_umask);
                return (-1);
        }
        (void)umask(old_umask);

        if (chmod(cs->cs_name, mode) == -1) {
                log_warn("%s: chmod", __func__);
                close(fd);
                (void)unlink(cs->cs_name);
                return (-1);
        }

        cs->cs_fd = fd;
        cs->cs_env = ps;

        return (0);
}

int
control_reset(struct control_sock *cs)
{
        /* Updating owner of the control socket */
        if (chown(cs->cs_name, cs->cs_uid, cs->cs_gid) == -1)
                return (-1);

        return (0);
}

int
control_listen(struct control_sock *cs)
{
        if (cs->cs_name == NULL)
                return (0);

        if (listen(cs->cs_fd, CONTROL_BACKLOG) == -1) {
                log_warn("%s: listen", __func__);
                return (-1);
        }

        event_set(&cs->cs_ev, cs->cs_fd, EV_READ, control_accept, cs);
        event_add(&cs->cs_ev, NULL);
        evtimer_set(&cs->cs_evt, control_accept, cs);

        return (0);
}

void
control_accept(int listenfd, short event, void *arg)
{
        struct control_sock     *cs = arg;
        int                      connfd;
        socklen_t                len;
        struct sockaddr_un       sun;
        struct ctl_conn         *c;

        event_add(&cs->cs_ev, NULL);
        if ((event & EV_TIMEOUT))
                return;

        len = sizeof(sun);
        if ((connfd = accept4(listenfd,
            (struct sockaddr *)&sun, &len, SOCK_NONBLOCK)) == -1) {
                /*
                 * Pause accept if we are out of file descriptors, or
                 * libevent will haunt us here too.
                 */
                if (errno == ENFILE || errno == EMFILE) {
                        struct timeval evtpause = { 1, 0 };

                        event_del(&cs->cs_ev);
                        evtimer_add(&cs->cs_evt, &evtpause);
                } else if (errno != EWOULDBLOCK && errno != EINTR &&
                    errno != ECONNABORTED)
                        log_warn("%s: accept", __func__);
                return;
        }

        if ((c = calloc(1, sizeof(struct ctl_conn))) == NULL) {
                log_warn("%s", __func__);
                close(connfd);
                return;
        }

        if (getsockopt(connfd, SOL_SOCKET, SO_PEERCRED,
            &c->peercred, &len) != 0) {
                log_warn("%s: failed to get peer credentials", __func__);
                close(connfd);
                free(c);
                return;
        }

        if (imsgbuf_init(&c->iev.ibuf, connfd) == -1) {
                log_warn("%s: failed to init imsgbuf", __func__);
                close(connfd);
                free(c);
                return;
        }
        imsgbuf_allow_fdpass(&c->iev.ibuf);
        c->iev.handler = control_dispatch_imsg;
        c->iev.events = EV_READ;
        c->iev.data = cs;
        event_set(&c->iev.ev, c->iev.ibuf.fd, c->iev.events,
            c->iev.handler, c->iev.data);
        event_add(&c->iev.ev, NULL);

        TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
}

struct ctl_conn *
control_connbyfd(int fd)
{
        struct ctl_conn *c;

        TAILQ_FOREACH(c, &ctl_conns, entry) {
                if (c->iev.ibuf.fd == fd)
                        break;
        }

        return (c);
}

void
control_close(int fd, struct control_sock *cs)
{
        struct ctl_conn         *c;
        struct ctl_notify       *notify, *notify_next;

        if ((c = control_connbyfd(fd)) == NULL) {
                log_warn("%s: fd %d: not found", __func__, fd);
                return;
        }

        imsgbuf_clear(&c->iev.ibuf);
        TAILQ_REMOVE(&ctl_conns, c, entry);

        TAILQ_FOREACH_SAFE(notify, &ctl_notify_q, entry, notify_next) {
                if (notify->ctl_fd == fd) {
                        TAILQ_REMOVE(&ctl_notify_q, notify, entry);
                        free(notify);
                        break;
                }
        }

        event_del(&c->iev.ev);
        close(c->iev.ibuf.fd);

        /* Some file descriptors are available again. */
        if (evtimer_pending(&cs->cs_evt, NULL)) {
                evtimer_del(&cs->cs_evt);
                event_add(&cs->cs_ev, NULL);
        }

        free(c);
}

void
control_dispatch_imsg(int fd, short event, void *arg)
{
        struct control_sock             *cs = arg;
        struct privsep                  *ps = cs->cs_env;
        struct ctl_conn                 *c;
        struct imsg                      imsg;
        struct vmop_create_params        vmc;
        struct vmop_id                   vid;
        struct ctl_notify               *notify;
        int                              kernfd, n, v, wait = 0, ret = 0;
        uint32_t                         peer_id = fd, type;

        if ((c = control_connbyfd(fd)) == NULL) {
                log_warn("%s: fd %d: not found", __func__, fd);
                return;
        }

        if (event & EV_READ) {
                if (imsgbuf_read(&c->iev.ibuf) != 1) {
                        control_close(fd, cs);
                        return;
                }
        }
        if (event & EV_WRITE) {
                if (imsgbuf_write(&c->iev.ibuf) == -1) {
                        control_close(fd, cs);
                        return;
                }
        }

        for (;;) {
                if ((n = imsgbuf_get(&c->iev.ibuf, &imsg)) == -1) {
                        control_close(fd, cs);
                        return;
                }

                if (n == 0)
                        break;

                type = imsg_get_type(&imsg);

                switch (type) {
                case IMSG_VMDOP_GET_INFO_VM_REQUEST:
                        if (imsg_get_len(&imsg) != 0)
                                goto fail_imsg;
                        break;
                case IMSG_VMDOP_WAIT_VM_REQUEST:
                case IMSG_VMDOP_TERMINATE_VM_REQUEST:
                case IMSG_VMDOP_PAUSE_VM:
                case IMSG_VMDOP_UNPAUSE_VM:
                        if (imsg_get_len(&imsg) != sizeof(vid))
                                goto fail_imsg;
                        break;
                case IMSG_VMDOP_START_VM_REQUEST:
                        if (imsg_get_len(&imsg) != sizeof(vmc))
                                goto fail_imsg;
                        break;
                default:
                        if (c->peercred.uid != 0) {
                                log_warnx("denied request %d from uid %d",
                                    type, c->peercred.uid);
                                ret = EPERM;
                                goto fail;
                        }
                        break;
                }

                switch (type) {
                case IMSG_CTL_VERBOSE:
                        v = imsg_int_read(&imsg);
                        log_setverbose(v);
                        if (proc_compose_imsg(ps, PROC_PARENT, type,
                            peer_id, -1, &v, sizeof(v)))
                                goto fail;
                        break;
                case IMSG_CTL_RESET:
                case IMSG_VMDOP_LOAD:
                case IMSG_VMDOP_RELOAD:
                        if (proc_forward_imsg(ps, &imsg, PROC_PARENT, peer_id))
                                goto fail;
                        break;
                case IMSG_VMDOP_START_VM_REQUEST:
                        vmop_create_params_read(&imsg, &vmc);
                        vmc.vmc_owner.uid = c->peercred.uid;
                        vmc.vmc_owner.gid = -1;

                        /* imsg passed fd may contain kernel image fd. */
                        kernfd = imsg_get_fd(&imsg);
                        if (proc_compose_imsg(ps, PROC_PARENT, type,
                            peer_id, kernfd, &vmc,
                            sizeof(vmc)) == -1) {
                                close_fd(kernfd);
                                control_close(fd, cs);
                                return;
                        }
                        break;
                case IMSG_VMDOP_WAIT_VM_REQUEST:
                        wait = 1;
                        /* FALLTHROUGH */
                case IMSG_VMDOP_TERMINATE_VM_REQUEST:
                        vmop_id_read(&imsg, &vid);
                        vid.vid_uid = c->peercred.uid;

                        if (wait || vid.vid_flags & VMOP_WAIT) {
                                vid.vid_flags |= VMOP_WAIT;
                                notify = calloc(1, sizeof(struct ctl_notify));
                                if (notify == NULL)
                                        fatal("%s: calloc", __func__);
                                notify->ctl_vmid = vid.vid_id;
                                notify->ctl_fd = fd;
                                TAILQ_INSERT_TAIL(&ctl_notify_q, notify, entry);
                                log_debug("%s: registered wait for peer %d",
                                    __func__, fd);
                        }

                        if (proc_compose_imsg(ps, PROC_PARENT, type,
                            peer_id, -1, &vid, sizeof(vid))) {
                                log_debug("%s: proc_compose_imsg failed",
                                    __func__);
                                control_close(fd, cs);
                                return;
                        }
                        break;
                case IMSG_VMDOP_GET_INFO_VM_REQUEST:
                        if (proc_compose_imsg(ps, PROC_PARENT, type,
                            peer_id, -1, NULL, 0)) {
                                control_close(fd, cs);
                                return;
                        }
                        break;
                case IMSG_VMDOP_PAUSE_VM:
                case IMSG_VMDOP_UNPAUSE_VM:
                        vmop_id_read(&imsg, &vid);
                        vid.vid_uid = c->peercred.uid;
                        log_debug("%s id: %d, name: %s, uid: %d", __func__,
                            vid.vid_id, vid.vid_name, vid.vid_uid);

                        if (proc_compose_imsg(ps, PROC_PARENT, type,
                            peer_id, imsg_get_fd(&imsg), &vid, sizeof(vid)))
                                goto fail;
                        break;
                default:
                        log_debug("%s: error handling imsg %d", __func__, type);
                        control_close(fd, cs);
                        break;
                }
                imsg_free(&imsg);
        }

        imsg_event_add(&c->iev);
        return;

 fail_imsg:
        imsg_free(&imsg);
 fail:
        if (ret == 0)
                ret = EINVAL;
        imsg_compose_event(&c->iev, IMSG_CTL_FAIL, 0, 0, -1, &ret, sizeof(ret));
        imsgbuf_flush(&c->iev.ibuf);
        control_close(fd, cs);
}