diff options
| -rw-r--r-- | Makefile | 4 | ||||
| -rwxr-xr-x | configure | 14 | ||||
| -rw-r--r-- | docs/interop/pr-helper.rst | 83 | ||||
| -rw-r--r-- | docs/pr-manager.rst | 33 | ||||
| -rw-r--r-- | scsi/pr-helper.h | 41 | ||||
| -rw-r--r-- | scsi/qemu-pr-helper.c | 735 |
6 files changed, 905 insertions, 5 deletions
@@ -372,6 +372,8 @@ qemu-bridge-helper$(EXESUF): qemu-bridge-helper.o $(COMMON_LDADDS) fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o fsdev/9p-marshal.o fsdev/9p-iov-marshal.o $(COMMON_LDADDS) fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap +scsi/qemu-pr-helper$(EXESUF): scsi/qemu-pr-helper.o scsi/utils.o $(crypto-obj-y) $(io-obj-y) $(qom-obj-y) $(COMMON_LDADDS) + qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx $(SRC_PATH)/scripts/hxtool $(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@,"GEN","$@") @@ -488,7 +490,7 @@ clean: rm -f *.msi find . \( -name '*.so' -o -name '*.dll' -o -name '*.mo' -o -name '*.[oda]' \) -type f -exec rm {} + rm -f $(filter-out %.tlb,$(TOOLS)) $(HELPERS-y) qemu-ga TAGS cscope.* *.pod *~ */*~ - rm -f fsdev/*.pod + rm -f fsdev/*.pod scsi/*.pod rm -f qemu-img-cmds.h rm -f ui/shader/*-vert.h ui/shader/*-frag.h @# May not be present in GENERATED_FILES @@ -5034,16 +5034,22 @@ if test "$want_tools" = "yes" ; then fi fi if test "$softmmu" = yes ; then - if test "$virtfs" != no ; then - if test "$cap" = yes && test "$linux" = yes && test "$attr" = yes ; then + if test "$linux" = yes; then + if test "$virtfs" != no && test "$cap" = yes && test "$attr" = yes ; then virtfs=yes tools="$tools fsdev/virtfs-proxy-helper\$(EXESUF)" else if test "$virtfs" = yes; then - error_exit "VirtFS is supported only on Linux and requires libcap devel and libattr devel" + error_exit "VirtFS requires libcap devel and libattr devel" fi virtfs=no fi + tools="$tools scsi/qemu-pr-helper\$(EXESUF)" + else + if test "$virtfs" = yes; then + error_exit "VirtFS is supported only on Linux" + fi + virtfs=no fi fi @@ -6506,7 +6512,7 @@ fi # build tree in object directory in case the source is not in the current directory DIRS="tests tests/tcg tests/tcg/cris tests/tcg/lm32 tests/libqos tests/qapi-schema tests/tcg/xtensa tests/qemu-iotests" -DIRS="$DIRS docs docs/interop fsdev" +DIRS="$DIRS docs docs/interop fsdev scsi" DIRS="$DIRS pc-bios/optionrom pc-bios/spapr-rtas pc-bios/s390-ccw" DIRS="$DIRS roms/seabios roms/vgabios" DIRS="$DIRS qapi-generated" diff --git a/docs/interop/pr-helper.rst b/docs/interop/pr-helper.rst new file mode 100644 index 0000000..9f76d5b --- /dev/null +++ b/docs/interop/pr-helper.rst @@ -0,0 +1,83 @@ +.. + +====================================== +Persistent reservation helper protocol +====================================== + +QEMU's SCSI passthrough devices, ``scsi-block`` and ``scsi-generic``, +can delegate implementation of persistent reservations to an external +(and typically privileged) program. Persistent Reservations allow +restricting access to block devices to specific initiators in a shared +storage setup. + +For a more detailed reference please refer the the SCSI Primary +Commands standard, specifically the section on Reservations and the +"PERSISTENT RESERVE IN" and "PERSISTENT RESERVE OUT" commands. + +This document describes the socket protocol used between QEMU's +``pr-manager-helper`` object and the external program. + +.. contents:: + +Connection and initialization +----------------------------- + +All data transmitted on the socket is big-endian. + +After connecting to the helper program's socket, the helper starts a simple +feature negotiation process by writing four bytes corresponding to +the features it exposes (``supported_features``). QEMU reads it, +then writes four bytes corresponding to the desired features of the +helper program (``requested_features``). + +If a bit is 1 in ``requested_features`` and 0 in ``supported_features``, +the corresponding feature is not supported by the helper and the connection +is closed. On the other hand, it is acceptable for a bit to be 0 in +``requested_features`` and 1 in ``supported_features``; in this case, +the helper will not enable the feature. + +Right now no feature is defined, so the two parties always write four +zero bytes. + +Command format +-------------- + +It is invalid to send multiple commands concurrently on the same +socket. It is however possible to connect multiple sockets to the +helper and send multiple commands to the helper for one or more +file descriptors. + +A command consists of a request and a response. A request consists +of a 16-byte SCSI CDB. A file descriptor must be passed to the helper +together with the SCSI CDB using ancillary data. + +The CDB has the following limitations: + +- the command (stored in the first byte) must be one of 0x5E + (PERSISTENT RESERVE IN) or 0x5F (PERSISTENT RESERVE OUT). + +- the allocation length (stored in bytes 7-8 of the CDB for PERSISTENT + RESERVE IN) or parameter list length (stored in bytes 5-8 of the CDB + for PERSISTENT RESERVE OUT) is limited to 8 KiB. + +For PERSISTENT RESERVE OUT, the parameter list is sent right after the +CDB. The length of the parameter list is taken from the CDB itself. + +The helper's reply has the following structure: + +- 4 bytes for the SCSI status + +- 4 bytes for the payload size (nonzero only for PERSISTENT RESERVE IN + and only if the SCSI status is 0x00, i.e. GOOD) + +- 96 bytes for the SCSI sense data + +- if the size is nonzero, the payload follows + +The sense data is always sent to keep the protocol simple, even though +it is only valid if the SCSI status is CHECK CONDITION (0x02). + +The payload size is always less than or equal to the allocation length +specified in the CDB for the PERSISTENT RESERVE IN command. + +If the protocol is violated, the helper closes the socket. diff --git a/docs/pr-manager.rst b/docs/pr-manager.rst index b6089fb..7107e59 100644 --- a/docs/pr-manager.rst +++ b/docs/pr-manager.rst @@ -49,3 +49,36 @@ Alternatively, using ``-blockdev``:: -object pr-manager-helper,id=helper0,path=/var/run/qemu-pr-helper.sock -blockdev node-name=hd,driver=raw,file.driver=host_device,file.filename=/dev/sdb,file.pr-manager=helper0 -device scsi-block,drive=hd + +---------------------------------- +Invoking :program:`qemu-pr-helper` +---------------------------------- + +QEMU provides an implementation of the persistent reservation helper, +called :program:`qemu-pr-helper`. The helper should be started as a +system service and supports the following option: + +-d, --daemon run in the background +-q, --quiet decrease verbosity +-f, --pidfile=path PID file when running as a daemon +-k, --socket=path path to the socket +-T, --trace=trace-opts tracing options + +By default, the socket and PID file are placed in the runtime state +directory, for example :file:`/var/run/qemu-pr-helper.sock` and +:file:`/var/run/qemu-pr-helper.pid`. The PID file is not created +unless :option:`-d` is passed too. + +:program:`qemu-pr-helper` can also use the systemd socket activation +protocol. In this case, the systemd socket unit should specify a +Unix stream socket, like this:: + + [Socket] + ListenStream=/var/run/qemu-pr-helper.sock + +After connecting to the socket, :program:`qemu-pr-helper`` can optionally drop +root privileges, except for those capabilities that are needed for +its operation. To do this, add the following options: + +-u, --user=user user to drop privileges to +-g, --group=group group to drop privileges to diff --git a/scsi/pr-helper.h b/scsi/pr-helper.h new file mode 100644 index 0000000..96c50a9 --- /dev/null +++ b/scsi/pr-helper.h @@ -0,0 +1,41 @@ +/* Definitions for QEMU's persistent reservation helper daemon + * + * Copyright (C) 2017 Red Hat, Inc. + * + * Author: + * Paolo Bonzini <pbonzini@redhat.com> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to + * deal in the Software without restriction, including without limitation the + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or + * sell copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ +#ifndef QEMU_PR_HELPER_H +#define QEMU_PR_HELPER_H 1 + +#include <stdint.h> + +#define PR_HELPER_CDB_SIZE 16 +#define PR_HELPER_SENSE_SIZE 96 +#define PR_HELPER_DATA_SIZE 8192 + +typedef struct PRHelperResponse { + int32_t result; + int32_t sz; + uint8_t sense[PR_HELPER_SENSE_SIZE]; +} PRHelperResponse; + +#endif diff --git a/scsi/qemu-pr-helper.c b/scsi/qemu-pr-helper.c new file mode 100644 index 0000000..f46266f --- /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); +} |