qemu/contrib/vhost-user-scsi/vhost-user-scsi.c
Stefan Hajnoczi 6852c21db2 vhost-user-scsi: avoid unlink(NULL) with fd passing
Commit 747421e949 ("Implements Backend
Program conventions for vhost-user-scsi") introduced fd-passing support
as part of implementing the vhost-user backend program conventions.

When fd passing is used the UNIX domain socket path is NULL and we must
not call unlink(2).

The unlink(2) call is necessary when the listen socket, lsock, was
created successfully since that means the UNIX domain socket is visible
in the file system.

Fixes: Coverity CID 1488353
Fixes: 747421e949 ("Implements Backend Program conventions for vhost-user-scsi")
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20220516155701.1789638-1-stefanha@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2022-05-16 16:48:35 -04:00

467 lines
12 KiB
C

/*
* vhost-user-scsi sample application
*
* Copyright (c) 2016 Nutanix Inc. All rights reserved.
*
* Author:
* Felipe Franciosi <felipe@nutanix.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 only.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <iscsi/iscsi.h>
#define inline __attribute__((gnu_inline)) /* required for libiscsi v1.9.0 */
#include <iscsi/scsi-lowlevel.h>
#undef inline
#include "libvhost-user-glib.h"
#include "standard-headers/linux/virtio_scsi.h"
#define VUS_ISCSI_INITIATOR "iqn.2016-11.com.nutanix:vhost-user-scsi"
enum {
VHOST_USER_SCSI_MAX_QUEUES = 8,
};
typedef struct VusIscsiLun {
struct iscsi_context *iscsi_ctx;
int iscsi_lun;
} VusIscsiLun;
typedef struct VusDev {
VugDev parent;
VusIscsiLun lun;
GMainLoop *loop;
} VusDev;
/** libiscsi integration **/
typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
static int vus_iscsi_add_lun(VusIscsiLun *lun, char *iscsi_uri)
{
struct iscsi_url *iscsi_url;
struct iscsi_context *iscsi_ctx;
int ret = 0;
assert(lun);
assert(iscsi_uri);
assert(!lun->iscsi_ctx);
iscsi_ctx = iscsi_create_context(VUS_ISCSI_INITIATOR);
if (!iscsi_ctx) {
g_warning("Unable to create iSCSI context");
return -1;
}
iscsi_url = iscsi_parse_full_url(iscsi_ctx, iscsi_uri);
if (!iscsi_url) {
g_warning("Unable to parse iSCSI URL: %s", iscsi_get_error(iscsi_ctx));
goto fail;
}
iscsi_set_session_type(iscsi_ctx, ISCSI_SESSION_NORMAL);
iscsi_set_header_digest(iscsi_ctx, ISCSI_HEADER_DIGEST_NONE_CRC32C);
if (iscsi_full_connect_sync(iscsi_ctx, iscsi_url->portal, iscsi_url->lun)) {
g_warning("Unable to login to iSCSI portal: %s",
iscsi_get_error(iscsi_ctx));
goto fail;
}
lun->iscsi_ctx = iscsi_ctx;
lun->iscsi_lun = iscsi_url->lun;
g_debug("Context %p created for lun 0: %s", iscsi_ctx, iscsi_uri);
out:
if (iscsi_url) {
iscsi_destroy_url(iscsi_url);
}
return ret;
fail:
(void)iscsi_destroy_context(iscsi_ctx);
ret = -1;
goto out;
}
static struct scsi_task *scsi_task_new(int cdb_len, uint8_t *cdb, int dir,
int xfer_len)
{
struct scsi_task *task;
assert(cdb_len > 0);
assert(cdb);
task = g_new0(struct scsi_task, 1);
memcpy(task->cdb, cdb, cdb_len);
task->cdb_size = cdb_len;
task->xfer_dir = dir;
task->expxferlen = xfer_len;
return task;
}
static int get_cdb_len(uint8_t *cdb)
{
assert(cdb);
switch (cdb[0] >> 5) {
case 0: return 6;
case 1: /* fall through */
case 2: return 10;
case 4: return 16;
case 5: return 12;
}
g_warning("Unable to determine cdb len (0x%02hhX)", (uint8_t)(cdb[0] >> 5));
return -1;
}
static int handle_cmd_sync(struct iscsi_context *ctx,
VirtIOSCSICmdReq *req,
struct iovec *out, unsigned int out_len,
VirtIOSCSICmdResp *rsp,
struct iovec *in, unsigned int in_len)
{
struct scsi_task *task;
uint32_t dir;
uint32_t len;
int cdb_len;
int i;
assert(ctx);
assert(req);
assert(rsp);
if (!(!req->lun[1] && req->lun[2] == 0x40 && !req->lun[3])) {
/* Ignore anything different than target=0, lun=0 */
g_debug("Ignoring unconnected lun (0x%hhX, 0x%hhX)",
req->lun[1], req->lun[3]);
rsp->status = SCSI_STATUS_CHECK_CONDITION;
memset(rsp->sense, 0, sizeof(rsp->sense));
rsp->sense_len = 18;
rsp->sense[0] = 0x70;
rsp->sense[2] = SCSI_SENSE_ILLEGAL_REQUEST;
rsp->sense[7] = 10;
rsp->sense[12] = 0x24;
return 0;
}
cdb_len = get_cdb_len(req->cdb);
if (cdb_len == -1) {
return -1;
}
len = 0;
if (!out_len && !in_len) {
dir = SCSI_XFER_NONE;
} else if (out_len) {
dir = SCSI_XFER_WRITE;
for (i = 0; i < out_len; i++) {
len += out[i].iov_len;
}
} else {
dir = SCSI_XFER_READ;
for (i = 0; i < in_len; i++) {
len += in[i].iov_len;
}
}
task = scsi_task_new(cdb_len, req->cdb, dir, len);
if (dir == SCSI_XFER_WRITE) {
task->iovector_out.iov = (struct scsi_iovec *)out;
task->iovector_out.niov = out_len;
} else if (dir == SCSI_XFER_READ) {
task->iovector_in.iov = (struct scsi_iovec *)in;
task->iovector_in.niov = in_len;
}
g_debug("Sending iscsi cmd (cdb_len=%d, dir=%d, task=%p)",
cdb_len, dir, task);
if (!iscsi_scsi_command_sync(ctx, 0, task, NULL)) {
g_warning("Error serving SCSI command");
g_free(task);
return -1;
}
memset(rsp, 0, sizeof(*rsp));
rsp->status = task->status;
rsp->resid = task->residual;
if (task->status == SCSI_STATUS_CHECK_CONDITION) {
rsp->response = VIRTIO_SCSI_S_FAILURE;
rsp->sense_len = task->datain.size - 2;
memcpy(rsp->sense, &task->datain.data[2], rsp->sense_len);
}
g_free(task);
g_debug("Filled in rsp: status=%hhX, resid=%u, response=%hhX, sense_len=%u",
rsp->status, rsp->resid, rsp->response, rsp->sense_len);
return 0;
}
/** libvhost-user callbacks **/
static void vus_panic_cb(VuDev *vu_dev, const char *buf)
{
VugDev *gdev;
VusDev *vdev_scsi;
assert(vu_dev);
gdev = container_of(vu_dev, VugDev, parent);
vdev_scsi = container_of(gdev, VusDev, parent);
if (buf) {
g_warning("vu_panic: %s", buf);
}
g_main_loop_quit(vdev_scsi->loop);
}
static void vus_proc_req(VuDev *vu_dev, int idx)
{
VugDev *gdev;
VusDev *vdev_scsi;
VuVirtq *vq;
VuVirtqElement *elem = NULL;
assert(vu_dev);
gdev = container_of(vu_dev, VugDev, parent);
vdev_scsi = container_of(gdev, VusDev, parent);
vq = vu_get_queue(vu_dev, idx);
if (!vq) {
g_warning("Error fetching VQ (dev=%p, idx=%d)", vu_dev, idx);
vus_panic_cb(vu_dev, NULL);
return;
}
g_debug("Got kicked on vq[%d]@%p", idx, vq);
while (1) {
VirtIOSCSICmdReq *req;
VirtIOSCSICmdResp *rsp;
elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement));
if (!elem) {
g_debug("No more elements pending on vq[%d]@%p", idx, vq);
break;
}
g_debug("Popped elem@%p", elem);
assert(!(elem->out_num > 1 && elem->in_num > 1));
assert(elem->out_num > 0 && elem->in_num > 0);
if (elem->out_sg[0].iov_len < sizeof(VirtIOSCSICmdReq)) {
g_warning("Invalid virtio-scsi req header");
vus_panic_cb(vu_dev, NULL);
break;
}
req = (VirtIOSCSICmdReq *)elem->out_sg[0].iov_base;
if (elem->in_sg[0].iov_len < sizeof(VirtIOSCSICmdResp)) {
g_warning("Invalid virtio-scsi rsp header");
vus_panic_cb(vu_dev, NULL);
break;
}
rsp = (VirtIOSCSICmdResp *)elem->in_sg[0].iov_base;
if (handle_cmd_sync(vdev_scsi->lun.iscsi_ctx,
req, &elem->out_sg[1], elem->out_num - 1,
rsp, &elem->in_sg[1], elem->in_num - 1) != 0) {
vus_panic_cb(vu_dev, NULL);
break;
}
vu_queue_push(vu_dev, vq, elem, 0);
vu_queue_notify(vu_dev, vq);
free(elem);
}
free(elem);
}
static void vus_queue_set_started(VuDev *vu_dev, int idx, bool started)
{
VuVirtq *vq;
assert(vu_dev);
vq = vu_get_queue(vu_dev, idx);
if (idx == 0 || idx == 1) {
g_debug("queue %d unimplemented", idx);
} else {
vu_set_queue_handler(vu_dev, vq, started ? vus_proc_req : NULL);
}
}
static const VuDevIface vus_iface = {
.queue_set_started = vus_queue_set_started,
};
/** misc helpers **/
static int unix_sock_new(char *unix_fn)
{
int sock;
struct sockaddr_un un;
size_t len;
assert(unix_fn);
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock < 0) {
perror("socket");
return -1;
}
un.sun_family = AF_UNIX;
(void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
len = sizeof(un.sun_family) + strlen(un.sun_path);
(void)unlink(unix_fn);
if (bind(sock, (struct sockaddr *)&un, len) < 0) {
perror("bind");
goto fail;
}
if (listen(sock, 1) < 0) {
perror("listen");
goto fail;
}
return sock;
fail:
(void)close(sock);
return -1;
}
/** vhost-user-scsi **/
static int opt_fdnum = -1;
static char *opt_socket_path;
static gboolean opt_print_caps;
static char *iscsi_uri;
static GOptionEntry entries[] = {
{ "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &opt_print_caps,
"Print capabilities", NULL },
{ "fd", 'f', 0, G_OPTION_ARG_INT, &opt_fdnum,
"Use inherited fd socket", "FDNUM" },
{ "iscsi-uri", 'i', 0, G_OPTION_ARG_FILENAME, &iscsi_uri,
"iSCSI URI to connect to", "FDNUM" },
{ "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
"Use UNIX socket path", "PATH" },
{ NULL, }
};
int main(int argc, char **argv)
{
VusDev *vdev_scsi = NULL;
int lsock = -1, csock = -1, err = EXIT_SUCCESS;
GError *error = NULL;
GOptionContext *context;
context = g_option_context_new(NULL);
g_option_context_add_main_entries(context, entries, NULL);
if (!g_option_context_parse(context, &argc, &argv, &error)) {
g_printerr("Option parsing failed: %s\n", error->message);
exit(EXIT_FAILURE);
}
if (opt_print_caps) {
g_print("{\n");
g_print(" \"type\": \"scsi\"\n");
g_print("}\n");
goto out;
}
if (!iscsi_uri) {
goto help;
}
if (opt_socket_path) {
lsock = unix_sock_new(opt_socket_path);
if (lsock < 0) {
exit(EXIT_FAILURE);
}
} else if (opt_fdnum < 0) {
g_print("%s\n", g_option_context_get_help(context, true, NULL));
exit(EXIT_FAILURE);
} else {
lsock = opt_fdnum;
}
csock = accept(lsock, NULL, NULL);
if (csock < 0) {
perror("accept");
goto err;
}
vdev_scsi = g_new0(VusDev, 1);
vdev_scsi->loop = g_main_loop_new(NULL, FALSE);
if (vus_iscsi_add_lun(&vdev_scsi->lun, iscsi_uri) != 0) {
goto err;
}
if (!vug_init(&vdev_scsi->parent, VHOST_USER_SCSI_MAX_QUEUES, csock,
vus_panic_cb, &vus_iface)) {
g_printerr("Failed to initialize libvhost-user-glib\n");
goto err;
}
g_main_loop_run(vdev_scsi->loop);
vug_deinit(&vdev_scsi->parent);
out:
if (vdev_scsi) {
g_main_loop_unref(vdev_scsi->loop);
g_free(vdev_scsi);
}
if (csock >= 0) {
close(csock);
}
if (lsock >= 0) {
close(lsock);
if (opt_socket_path) {
unlink(opt_socket_path);
}
}
g_free(opt_socket_path);
g_free(iscsi_uri);
return err;
err:
err = EXIT_FAILURE;
goto out;
help:
fprintf(stderr, "Usage: %s [ -s socket-path -i iscsi-uri -f fd -p print-capabilities ] | [ -h ]\n",
argv[0]);
fprintf(stderr, " -s, --socket-path=SOCKET_PATH path to unix socket\n");
fprintf(stderr, " -i, --iscsi-uri=ISCSI_URI iscsi uri for lun 0\n");
fprintf(stderr, " -f, --fd=FILE_DESCRIPTOR file-descriptor\n");
fprintf(stderr, " -p, --print-capabilities=PRINT_CAPABILITIES denotes print-capabilities\n");
fprintf(stderr, " -h print help and quit\n");
goto err;
}