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-rw-r--r--scsi/qemu-pr-helper.c735
1 files changed, 735 insertions, 0 deletions
diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c
new file mode 100644
index 0000000000..f46266f733
--- /dev/null
+++ b/scsi/qemu-pr-helper.c
@@ -0,0 +1,735 @@
+/*
+ * Privileged helper to handle persistent reservation commands for QEMU
+ *
+ * Copyright (C) 2017 Red Hat, Inc. <pbonzini@redhat.com>
+ *
+ * Author: Paolo Bonzini <pbonzini@redhat.com>
+ *
+ * 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; under version 2 of the License.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <linux/dm-ioctl.h>
+#include <scsi/sg.h>
+
+#ifdef CONFIG_LIBCAP
+#include <cap-ng.h>
+#endif
+#include <pwd.h>
+#include <grp.h>
+
+#include "qapi/error.h"
+#include "qemu-common.h"
+#include "qemu/cutils.h"
+#include "qemu/main-loop.h"
+#include "qemu/error-report.h"
+#include "qemu/config-file.h"
+#include "qemu/bswap.h"
+#include "qemu/log.h"
+#include "qemu/systemd.h"
+#include "qapi/util.h"
+#include "qapi/qmp/qstring.h"
+#include "io/channel-socket.h"
+#include "trace/control.h"
+#include "qemu-version.h"
+
+#include "block/aio.h"
+#include "block/thread-pool.h"
+
+#include "scsi/constants.h"
+#include "scsi/utils.h"
+#include "pr-helper.h"
+
+#define PR_OUT_FIXED_PARAM_SIZE 24
+
+static char *socket_path;
+static char *pidfile;
+static enum { RUNNING, TERMINATE, TERMINATING } state;
+static QIOChannelSocket *server_ioc;
+static int server_watch;
+static int num_active_sockets = 1;
+static int verbose;
+
+#ifdef CONFIG_LIBCAP
+static int uid = -1;
+static int gid = -1;
+#endif
+
+static void usage(const char *name)
+{
+ (printf) (
+"Usage: %s [OPTIONS] FILE\n"
+"Persistent Reservation helper program for QEMU\n"
+"\n"
+" -h, --help display this help and exit\n"
+" -V, --version output version information and exit\n"
+"\n"
+" -d, --daemon run in the background\n"
+" -f, --pidfile=PATH PID file when running as a daemon\n"
+" (default '%s')\n"
+" -k, --socket=PATH path to the unix socket\n"
+" (default '%s')\n"
+" -T, --trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n"
+" specify tracing options\n"
+#ifdef CONFIG_LIBCAP
+" -u, --user=USER user to drop privileges to\n"
+" -g, --group=GROUP group to drop privileges to\n"
+#endif
+"\n"
+QEMU_HELP_BOTTOM "\n"
+ , name, pidfile, socket_path);
+}
+
+static void version(const char *name)
+{
+ printf(
+"%s " QEMU_VERSION QEMU_PKGVERSION "\n"
+"Written by Paolo Bonzini.\n"
+"\n"
+QEMU_COPYRIGHT "\n"
+"This is free software; see the source for copying conditions. There is NO\n"
+"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
+ , name);
+}
+
+static void write_pidfile(void)
+{
+ int pidfd;
+ char pidstr[32];
+
+ pidfd = qemu_open(pidfile, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
+ if (pidfd == -1) {
+ error_report("Cannot open pid file, %s", strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+
+ if (lockf(pidfd, F_TLOCK, 0)) {
+ error_report("Cannot lock pid file, %s", strerror(errno));
+ goto fail;
+ }
+ if (ftruncate(pidfd, 0)) {
+ error_report("Failed to truncate pid file");
+ goto fail;
+ }
+
+ snprintf(pidstr, sizeof(pidstr), "%d\n", getpid());
+ if (write(pidfd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
+ error_report("Failed to write pid file");
+ goto fail;
+ }
+ return;
+
+fail:
+ unlink(pidfile);
+ close(pidfd);
+ exit(EXIT_FAILURE);
+}
+
+/* SG_IO support */
+
+typedef struct PRHelperSGIOData {
+ int fd;
+ const uint8_t *cdb;
+ uint8_t *sense;
+ uint8_t *buf;
+ int sz; /* input/output */
+ int dir;
+} PRHelperSGIOData;
+
+static int do_sgio_worker(void *opaque)
+{
+ PRHelperSGIOData *data = opaque;
+ struct sg_io_hdr io_hdr;
+ int ret;
+ int status;
+ SCSISense sense_code;
+
+ memset(data->sense, 0, PR_HELPER_SENSE_SIZE);
+ memset(&io_hdr, 0, sizeof(io_hdr));
+ io_hdr.interface_id = 'S';
+ io_hdr.cmd_len = PR_HELPER_CDB_SIZE;
+ io_hdr.cmdp = (uint8_t *)data->cdb;
+ io_hdr.sbp = data->sense;
+ io_hdr.mx_sb_len = PR_HELPER_SENSE_SIZE;
+ io_hdr.timeout = 1;
+ io_hdr.dxfer_direction = data->dir;
+ io_hdr.dxferp = (char *)data->buf;
+ io_hdr.dxfer_len = data->sz;
+ ret = ioctl(data->fd, SG_IO, &io_hdr);
+ status = sg_io_sense_from_errno(ret < 0 ? errno : 0, &io_hdr,
+ &sense_code);
+ if (status == GOOD) {
+ data->sz -= io_hdr.resid;
+ } else {
+ data->sz = 0;
+ }
+
+ if (status == CHECK_CONDITION &&
+ !(io_hdr.driver_status & SG_ERR_DRIVER_SENSE)) {
+ scsi_build_sense(data->sense, sense_code);
+ }
+
+ return status;
+}
+
+static int do_sgio(int fd, const uint8_t *cdb, uint8_t *sense,
+ uint8_t *buf, int *sz, int dir)
+{
+ ThreadPool *pool = aio_get_thread_pool(qemu_get_aio_context());
+ int r;
+
+ PRHelperSGIOData data = {
+ .fd = fd,
+ .cdb = cdb,
+ .sense = sense,
+ .buf = buf,
+ .sz = *sz,
+ .dir = dir,
+ };
+
+ r = thread_pool_submit_co(pool, do_sgio_worker, &data);
+ *sz = data.sz;
+ return r;
+}
+
+static int do_pr_in(int fd, const uint8_t *cdb, uint8_t *sense,
+ uint8_t *data, int *resp_sz)
+{
+ return do_sgio(fd, cdb, sense, data, resp_sz,
+ SG_DXFER_FROM_DEV);
+}
+
+static int do_pr_out(int fd, const uint8_t *cdb, uint8_t *sense,
+ const uint8_t *param, int sz)
+{
+ int resp_sz = sz;
+ return do_sgio(fd, cdb, sense, (uint8_t *)param, &resp_sz,
+ SG_DXFER_TO_DEV);
+}
+
+/* Client */
+
+typedef struct PRHelperClient {
+ QIOChannelSocket *ioc;
+ Coroutine *co;
+ int fd;
+ uint8_t data[PR_HELPER_DATA_SIZE];
+} PRHelperClient;
+
+typedef struct PRHelperRequest {
+ int fd;
+ size_t sz;
+ uint8_t cdb[PR_HELPER_CDB_SIZE];
+} PRHelperRequest;
+
+static int coroutine_fn prh_read(PRHelperClient *client, void *buf, int sz,
+ Error **errp)
+{
+ int ret = 0;
+
+ while (sz > 0) {
+ int *fds = NULL;
+ size_t nfds = 0;
+ int i;
+ struct iovec iov;
+ ssize_t n_read;
+
+ iov.iov_base = buf;
+ iov.iov_len = sz;
+ n_read = qio_channel_readv_full(QIO_CHANNEL(client->ioc), &iov, 1,
+ &fds, &nfds, errp);
+
+ if (n_read == QIO_CHANNEL_ERR_BLOCK) {
+ qio_channel_yield(QIO_CHANNEL(client->ioc), G_IO_IN);
+ continue;
+ }
+ if (n_read <= 0) {
+ ret = n_read ? n_read : -1;
+ goto err;
+ }
+
+ /* Stash one file descriptor per request. */
+ if (nfds) {
+ bool too_many = false;
+ for (i = 0; i < nfds; i++) {
+ if (client->fd == -1) {
+ client->fd = fds[i];
+ } else {
+ close(fds[i]);
+ too_many = true;
+ }
+ }
+ g_free(fds);
+ if (too_many) {
+ ret = -1;
+ goto err;
+ }
+ }
+
+ buf += n_read;
+ sz -= n_read;
+ }
+
+ return 0;
+
+err:
+ if (client->fd != -1) {
+ close(client->fd);
+ client->fd = -1;
+ }
+ return ret;
+}
+
+static int coroutine_fn prh_read_request(PRHelperClient *client,
+ PRHelperRequest *req,
+ PRHelperResponse *resp, Error **errp)
+{
+ uint32_t sz;
+
+ if (prh_read(client, req->cdb, sizeof(req->cdb), NULL) < 0) {
+ return -1;
+ }
+
+ if (client->fd == -1) {
+ error_setg(errp, "No file descriptor in request.");
+ return -1;
+ }
+
+ if (req->cdb[0] != PERSISTENT_RESERVE_OUT &&
+ req->cdb[0] != PERSISTENT_RESERVE_IN) {
+ error_setg(errp, "Invalid CDB, closing socket.");
+ goto out_close;
+ }
+
+ sz = scsi_cdb_xfer(req->cdb);
+ if (sz > sizeof(client->data)) {
+ goto out_close;
+ }
+
+ if (req->cdb[0] == PERSISTENT_RESERVE_OUT) {
+ if (qio_channel_read_all(QIO_CHANNEL(client->ioc),
+ (char *)client->data, sz,
+ errp) < 0) {
+ goto out_close;
+ }
+ if ((fcntl(client->fd, F_GETFL) & O_ACCMODE) == O_RDONLY) {
+ scsi_build_sense(resp->sense, SENSE_CODE(INVALID_OPCODE));
+ sz = 0;
+ } else if (sz < PR_OUT_FIXED_PARAM_SIZE) {
+ /* Illegal request, Parameter list length error. This isn't fatal;
+ * we have read the data, send an error without closing the socket.
+ */
+ scsi_build_sense(resp->sense, SENSE_CODE(INVALID_PARAM_LEN));
+ sz = 0;
+ }
+ if (sz == 0) {
+ resp->result = CHECK_CONDITION;
+ close(client->fd);
+ client->fd = -1;
+ }
+ }
+
+ req->fd = client->fd;
+ req->sz = sz;
+ client->fd = -1;
+ return sz;
+
+out_close:
+ close(client->fd);
+ client->fd = -1;
+ return -1;
+}
+
+static int coroutine_fn prh_write_response(PRHelperClient *client,
+ PRHelperRequest *req,
+ PRHelperResponse *resp, Error **errp)
+{
+ ssize_t r;
+ size_t sz;
+
+ if (req->cdb[0] == PERSISTENT_RESERVE_IN && resp->result == GOOD) {
+ assert(resp->sz <= req->sz && resp->sz <= sizeof(client->data));
+ } else {
+ assert(resp->sz == 0);
+ }
+
+ sz = resp->sz;
+
+ resp->result = cpu_to_be32(resp->result);
+ resp->sz = cpu_to_be32(resp->sz);
+ r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
+ (char *) resp, sizeof(*resp), errp);
+ if (r < 0) {
+ return r;
+ }
+
+ r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
+ (char *) client->data,
+ sz, errp);
+ return r < 0 ? r : 0;
+}
+
+static void coroutine_fn prh_co_entry(void *opaque)
+{
+ PRHelperClient *client = opaque;
+ Error *local_err = NULL;
+ uint32_t flags;
+ int r;
+
+ qio_channel_set_blocking(QIO_CHANNEL(client->ioc),
+ false, NULL);
+ qio_channel_attach_aio_context(QIO_CHANNEL(client->ioc),
+ qemu_get_aio_context());
+
+ /* A very simple negotiation for future extensibility. No features
+ * are defined so write 0.
+ */
+ flags = cpu_to_be32(0);
+ r = qio_channel_write_all(QIO_CHANNEL(client->ioc),
+ (char *) &flags, sizeof(flags), NULL);
+ if (r < 0) {
+ goto out;
+ }
+
+ r = qio_channel_read_all(QIO_CHANNEL(client->ioc),
+ (char *) &flags, sizeof(flags), NULL);
+ if (be32_to_cpu(flags) != 0 || r < 0) {
+ goto out;
+ }
+
+ while (atomic_read(&state) == RUNNING) {
+ PRHelperRequest req;
+ PRHelperResponse resp;
+ int sz;
+
+ sz = prh_read_request(client, &req, &resp, &local_err);
+ if (sz < 0) {
+ break;
+ }
+
+ if (sz > 0) {
+ num_active_sockets++;
+ if (req.cdb[0] == PERSISTENT_RESERVE_OUT) {
+ r = do_pr_out(req.fd, req.cdb, resp.sense,
+ client->data, sz);
+ resp.sz = 0;
+ } else {
+ resp.sz = sizeof(client->data);
+ r = do_pr_in(req.fd, req.cdb, resp.sense,
+ client->data, &resp.sz);
+ resp.sz = MIN(resp.sz, sz);
+ }
+ num_active_sockets--;
+ close(req.fd);
+ if (r == -1) {
+ break;
+ }
+ resp.result = r;
+ }
+
+ if (prh_write_response(client, &req, &resp, &local_err) < 0) {
+ break;
+ }
+ }
+
+ if (local_err) {
+ if (verbose == 0) {
+ error_free(local_err);
+ } else {
+ error_report_err(local_err);
+ }
+ }
+
+out:
+ qio_channel_detach_aio_context(QIO_CHANNEL(client->ioc));
+ object_unref(OBJECT(client->ioc));
+ g_free(client);
+}
+
+static gboolean accept_client(QIOChannel *ioc, GIOCondition cond, gpointer opaque)
+{
+ QIOChannelSocket *cioc;
+ PRHelperClient *prh;
+
+ cioc = qio_channel_socket_accept(QIO_CHANNEL_SOCKET(ioc),
+ NULL);
+ if (!cioc) {
+ return TRUE;
+ }
+
+ prh = g_new(PRHelperClient, 1);
+ prh->ioc = cioc;
+ prh->fd = -1;
+ prh->co = qemu_coroutine_create(prh_co_entry, prh);
+ qemu_coroutine_enter(prh->co);
+
+ return TRUE;
+}
+
+
+/*
+ * Check socket parameters compatibility when socket activation is used.
+ */
+static const char *socket_activation_validate_opts(void)
+{
+ if (socket_path != NULL) {
+ return "Unix socket can't be set when using socket activation";
+ }
+
+ return NULL;
+}
+
+static void compute_default_paths(void)
+{
+ if (!socket_path) {
+ socket_path = qemu_get_local_state_pathname("run/qemu-pr-helper.sock");
+ }
+}
+
+static void termsig_handler(int signum)
+{
+ atomic_cmpxchg(&state, RUNNING, TERMINATE);
+ qemu_notify_event();
+}
+
+static void close_server_socket(void)
+{
+ assert(server_ioc);
+
+ g_source_remove(server_watch);
+ server_watch = -1;
+ object_unref(OBJECT(server_ioc));
+ num_active_sockets--;
+}
+
+#ifdef CONFIG_LIBCAP
+static int drop_privileges(void)
+{
+ /* clear all capabilities */
+ capng_clear(CAPNG_SELECT_BOTH);
+
+ if (capng_update(CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
+ CAP_SYS_RAWIO) < 0) {
+ return -1;
+ }
+
+ /* Change user/group id, retaining the capabilities. Because file descriptors
+ * are passed via SCM_RIGHTS, we don't need supplementary groups (and in
+ * fact the helper can run as "nobody").
+ */
+ if (capng_change_id(uid != -1 ? uid : getuid(),
+ gid != -1 ? gid : getgid(),
+ CAPNG_DROP_SUPP_GRP | CAPNG_CLEAR_BOUNDING)) {
+ return -1;
+ }
+
+ return 0;
+}
+#endif
+
+int main(int argc, char **argv)
+{
+ const char *sopt = "hVk:fdT:u:g:q";
+ struct option lopt[] = {
+ { "help", no_argument, NULL, 'h' },
+ { "version", no_argument, NULL, 'V' },
+ { "socket", required_argument, NULL, 'k' },
+ { "pidfile", no_argument, NULL, 'f' },
+ { "daemon", no_argument, NULL, 'd' },
+ { "trace", required_argument, NULL, 'T' },
+ { "user", required_argument, NULL, 'u' },
+ { "group", required_argument, NULL, 'g' },
+ { "quiet", no_argument, NULL, 'q' },
+ { NULL, 0, NULL, 0 }
+ };
+ int opt_ind = 0;
+ int quiet = 0;
+ int ch;
+ Error *local_err = NULL;
+ char *trace_file = NULL;
+ bool daemonize = false;
+ unsigned socket_activation;
+
+ struct sigaction sa_sigterm;
+ memset(&sa_sigterm, 0, sizeof(sa_sigterm));
+ sa_sigterm.sa_handler = termsig_handler;
+ sigaction(SIGTERM, &sa_sigterm, NULL);
+ sigaction(SIGINT, &sa_sigterm, NULL);
+ sigaction(SIGHUP, &sa_sigterm, NULL);
+
+ signal(SIGPIPE, SIG_IGN);
+
+ module_call_init(MODULE_INIT_TRACE);
+ module_call_init(MODULE_INIT_QOM);
+ qemu_add_opts(&qemu_trace_opts);
+ qemu_init_exec_dir(argv[0]);
+
+ pidfile = qemu_get_local_state_pathname("run/qemu-pr-helper.pid");
+
+ while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
+ switch (ch) {
+ case 'k':
+ socket_path = optarg;
+ if (socket_path[0] != '/') {
+ error_report("socket path must be absolute");
+ exit(EXIT_FAILURE);
+ }
+ break;
+ case 'f':
+ pidfile = optarg;
+ break;
+#ifdef CONFIG_LIBCAP
+ case 'u': {
+ unsigned long res;
+ struct passwd *userinfo = getpwnam(optarg);
+ if (userinfo) {
+ uid = userinfo->pw_uid;
+ } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
+ (uid_t)res == res) {
+ uid = res;
+ } else {
+ error_report("invalid user '%s'", optarg);
+ exit(EXIT_FAILURE);
+ }
+ break;
+ }
+ case 'g': {
+ unsigned long res;
+ struct group *groupinfo = getgrnam(optarg);
+ if (groupinfo) {
+ gid = groupinfo->gr_gid;
+ } else if (qemu_strtoul(optarg, NULL, 10, &res) == 0 &&
+ (gid_t)res == res) {
+ gid = res;
+ } else {
+ error_report("invalid group '%s'", optarg);
+ exit(EXIT_FAILURE);
+ }
+ break;
+ }
+#else
+ case 'u':
+ case 'g':
+ error_report("-%c not supported by this %s", ch, argv[0]);
+ exit(1);
+#endif
+ case 'd':
+ daemonize = true;
+ break;
+ case 'q':
+ quiet = 1;
+ break;
+ case 'T':
+ g_free(trace_file);
+ trace_file = trace_opt_parse(optarg);
+ break;
+ case 'V':
+ version(argv[0]);
+ exit(EXIT_SUCCESS);
+ break;
+ case 'h':
+ usage(argv[0]);
+ exit(EXIT_SUCCESS);
+ break;
+ case '?':
+ error_report("Try `%s --help' for more information.", argv[0]);
+ exit(EXIT_FAILURE);
+ }
+ }
+
+ /* set verbosity */
+ verbose = !quiet;
+
+ if (!trace_init_backends()) {
+ exit(EXIT_FAILURE);
+ }
+ trace_init_file(trace_file);
+ qemu_set_log(LOG_TRACE);
+
+ socket_activation = check_socket_activation();
+ if (socket_activation == 0) {
+ SocketAddress saddr;
+ compute_default_paths();
+ saddr = (SocketAddress){
+ .type = SOCKET_ADDRESS_TYPE_UNIX,
+ .u.q_unix.path = g_strdup(socket_path)
+ };
+ server_ioc = qio_channel_socket_new();
+ if (qio_channel_socket_listen_sync(server_ioc, &saddr, &local_err) < 0) {
+ object_unref(OBJECT(server_ioc));
+ error_report_err(local_err);
+ return 1;
+ }
+ g_free(saddr.u.q_unix.path);
+ } else {
+ /* Using socket activation - check user didn't use -p etc. */
+ const char *err_msg = socket_activation_validate_opts();
+ if (err_msg != NULL) {
+ error_report("%s", err_msg);
+ exit(EXIT_FAILURE);
+ }
+
+ /* Can only listen on a single socket. */
+ if (socket_activation > 1) {
+ error_report("%s does not support socket activation with LISTEN_FDS > 1",
+ argv[0]);
+ exit(EXIT_FAILURE);
+ }
+ server_ioc = qio_channel_socket_new_fd(FIRST_SOCKET_ACTIVATION_FD,
+ &local_err);
+ if (server_ioc == NULL) {
+ error_report("Failed to use socket activation: %s",
+ error_get_pretty(local_err));
+ exit(EXIT_FAILURE);
+ }
+ socket_path = NULL;
+ }
+
+ if (qemu_init_main_loop(&local_err)) {
+ error_report_err(local_err);
+ exit(EXIT_FAILURE);
+ }
+
+ server_watch = qio_channel_add_watch(QIO_CHANNEL(server_ioc),
+ G_IO_IN,
+ accept_client,
+ NULL, NULL);
+
+#ifdef CONFIG_LIBCAP
+ if (drop_privileges() < 0) {
+ error_report("Failed to drop privileges: %s", strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+#endif
+
+ if (daemonize) {
+ if (daemon(0, 0) < 0) {
+ error_report("Failed to daemonize: %s", strerror(errno));
+ exit(EXIT_FAILURE);
+ }
+ write_pidfile();
+ }
+
+ state = RUNNING;
+ do {
+ main_loop_wait(false);
+ if (state == TERMINATE) {
+ state = TERMINATING;
+ close_server_socket();
+ }
+ } while (num_active_sockets > 0);
+
+ exit(EXIT_SUCCESS);
+}
generated by cgit v1.2.3 (git 2.26.2) at 2024-12-20 03:45:05 +0000