text: /*-
   *   BSD LICENSE
   *
   *   Copyright (c) Intel Corporation.
   *   All rights reserved.
   *
   *   Redistribution and use in source and binary forms, with or without
   *   modification, are permitted provided that the following conditions
   *   are met:
   *
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in
   *       the documentation and/or other materials provided with the
   *       distribution.
   *     * Neither the name of Intel Corporation nor the names of its
   *       contributors may be used to endorse or promote products derived
   *       from this software without specific prior written permission.
   *
   *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "spdk/string.h"
  #include "spdk/env.h"
  #include "spdk/rpc.h"
  #include "spdk/util.h"
  
  #include <linux/nbd.h>
  
  #include "nbd_internal.h"
  #include "spdk/log.h"
  
  struct rpc_nbd_start_disk {
  	char *bdev_name;
  	char *nbd_device;
  	/* Used to search one available nbd device */
  	int nbd_idx;
  	bool nbd_idx_specified;
  	struct spdk_jsonrpc_request *request;
  };
  
  static void
  free_rpc_nbd_start_disk(struct rpc_nbd_start_disk *req)
  {
  	free(req->bdev_name);
  	free(req->nbd_device);
  	free(req);
  }
  
  static const struct spdk_json_object_decoder rpc_nbd_start_disk_decoders[] = {
  	{"bdev_name", offsetof(struct rpc_nbd_start_disk, bdev_name), spdk_json_decode_string},
  	{"nbd_device", offsetof(struct rpc_nbd_start_disk, nbd_device), spdk_json_decode_string, true},
  };
  
  /* Return 0 to indicate the nbd_device might be available,
   * or non-zero to indicate the nbd_device is invalid or in use.
   */
  static int
  check_available_nbd_disk(char *nbd_device)
  {
  	char nbd_block_path[256];
  	char tail[2];
  	int rc;
  	unsigned int nbd_idx;
  	struct spdk_nbd_disk *nbd;
  
  	/* nbd device path must be in format of /dev/nbd<num>, with no tail. */
  	rc = sscanf(nbd_device, "/dev/nbd%u%1s", &nbd_idx, tail);
  	if (rc != 1) {
  		return -errno;
  	}
  
  	/* make sure nbd_device is not registered inside SPDK */
  	nbd = nbd_disk_find_by_nbd_path(nbd_device);
  	if (nbd) {
  		/* nbd_device is in use */
  		return -EBUSY;
  	}
  
  	/* A valid pid file in /sys/block indicates the device is in use */
  	snprintf(nbd_block_path, 256, "/sys/block/nbd%u/pid", nbd_idx);
  
  	rc = open(nbd_block_path, O_RDONLY);
  	if (rc < 0) {
  		if (errno == ENOENT) {
  			/* nbd_device might be available */
  			return 0;
  		} else {
  			SPDK_ERRLOG("Failed to check PID file %s: %s\n", nbd_block_path, spdk_strerror(errno));
  			return -errno;
  		}
  	}
  
  	close(rc);
  
  	/* nbd_device is in use */
  	return -EBUSY;
  }
  
  static char *
  find_available_nbd_disk(int nbd_idx, int *next_nbd_idx)
  {
  	int i, rc;
  	char nbd_device[20];
  
  	for (i = nbd_idx; ; i++) {
  		snprintf(nbd_device, 20, "/dev/nbd%d", i);
  		/* Check whether an nbd device exists in order to reach the last one nbd device */
  		rc = access(nbd_device, F_OK);
  		if (rc != 0) {
  			break;
  		}
  
  		rc = check_available_nbd_disk(nbd_device);
  		if (rc == 0) {
  			if (next_nbd_idx != NULL) {
  				*next_nbd_idx = i + 1;
  			}
  
  			return strdup(nbd_device);
  		}
  	}
  
  	return NULL;
  }
  
  static void
  rpc_start_nbd_done(void *cb_arg, struct spdk_nbd_disk *nbd, int rc)
  {
  	struct rpc_nbd_start_disk *req = cb_arg;
  	struct spdk_jsonrpc_request *request = req->request;
  	struct spdk_json_write_ctx *w;
  
  	/* Check whether it's automatic nbd-device assignment */
  	if (rc == -EBUSY && req->nbd_idx_specified == false) {
  		free(req->nbd_device);
  
  		req->nbd_device = find_available_nbd_disk(req->nbd_idx, &req->nbd_idx);
  		if (req->nbd_device != NULL) {
  			spdk_nbd_start(req->bdev_name, req->nbd_device,
  				       rpc_start_nbd_done, req);
  			return;
  		}
  
  		SPDK_INFOLOG(nbd, "There is no available nbd device.\n");
  	}
  
  	if (rc) {
  		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
  		return;
  	}
  
  	w = spdk_jsonrpc_begin_result(request);
  	spdk_json_write_string(w, spdk_nbd_get_path(nbd));
  	spdk_jsonrpc_end_result(request, w);
  
  	free_rpc_nbd_start_disk(req);
  }
  
  static void
  rpc_nbd_start_disk(struct spdk_jsonrpc_request *request,
  		   const struct spdk_json_val *params)
  {
  	struct rpc_nbd_start_disk *req;
  	int rc;
  
  	req = calloc(1, sizeof(*req));
  	if (req == NULL) {
  		SPDK_ERRLOG("could not allocate nbd_start_disk request.\n");
  		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, "Out of memory");
  		return;
  	}
  
  	if (spdk_json_decode_object(params, rpc_nbd_start_disk_decoders,
  				    SPDK_COUNTOF(rpc_nbd_start_disk_decoders),
  				    req)) {
  		SPDK_ERRLOG("spdk_json_decode_object failed\n");
  		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
  						 "spdk_json_decode_object failed");
  		goto invalid;
  	}
  
  	if (req->bdev_name == NULL) {
  		goto invalid;
  	}
  
  	if (req->nbd_device != NULL) {
  		req->nbd_idx_specified = true;
  		rc = check_available_nbd_disk(req->nbd_device);
  		if (rc == -EBUSY) {
  			SPDK_DEBUGLOG(nbd, "NBD device %s is in use.\n", req->nbd_device);
  			spdk_jsonrpc_send_error_response(request, -EBUSY, spdk_strerror(-rc));
  			goto invalid;
  		}
  
  		if (rc != 0) {
  			SPDK_DEBUGLOG(nbd, "Illegal nbd_device %s.\n", req->nbd_device);
  			spdk_jsonrpc_send_error_response_fmt(request, -ENODEV,
  							     "illegal nbd device %s", req->nbd_device);
  			goto invalid;
  		}
  	} else {
  		req->nbd_idx = 0;
  		req->nbd_device = find_available_nbd_disk(req->nbd_idx, &req->nbd_idx);
  		if (req->nbd_device == NULL) {
  			SPDK_INFOLOG(nbd, "There is no available nbd device.\n");
  			spdk_jsonrpc_send_error_response(request, -ENODEV,
  							 "nbd device not found");
  			goto invalid;
  		}
  	}
  
  	req->request = request;
  	spdk_nbd_start(req->bdev_name, req->nbd_device,
  		       rpc_start_nbd_done, req);
  
  	return;
  
  invalid:
  	free_rpc_nbd_start_disk(req);
  }
  
  SPDK_RPC_REGISTER("nbd_start_disk", rpc_nbd_start_disk, SPDK_RPC_RUNTIME)
  SPDK_RPC_REGISTER_ALIAS_DEPRECATED(nbd_start_disk, start_nbd_disk)
  
  struct rpc_nbd_stop_disk {
  	char *nbd_device;
  };
  
  static void
  free_rpc_nbd_stop_disk(struct rpc_nbd_stop_disk *req)
  {
  	free(req->nbd_device);
  }
  
  static const struct spdk_json_object_decoder rpc_nbd_stop_disk_decoders[] = {
  	{"nbd_device", offsetof(struct rpc_nbd_stop_disk, nbd_device), spdk_json_decode_string},
  };
  
  struct nbd_disconnect_arg {
  	struct spdk_jsonrpc_request *request;
  	struct spdk_nbd_disk *nbd;
  };
  
  static void *
  nbd_disconnect_thread(void *arg)
  {
  	struct nbd_disconnect_arg *thd_arg = arg;
  	struct spdk_json_write_ctx *w;
  
  	spdk_unaffinitize_thread();
  
  	nbd_disconnect(thd_arg->nbd);
  
  	w = spdk_jsonrpc_begin_result(thd_arg->request);
  	spdk_json_write_bool(w, true);
  	spdk_jsonrpc_end_result(thd_arg->request, w);
  
  	free(thd_arg);
  	pthread_exit(NULL);
  }
  
  static void
  rpc_nbd_stop_disk(struct spdk_jsonrpc_request *request,
  		  const struct spdk_json_val *params)
  {
  	struct rpc_nbd_stop_disk req = {};
  	struct spdk_nbd_disk *nbd;
  	pthread_t tid;
  	struct nbd_disconnect_arg *thd_arg = NULL;
  	int rc;
  
  	if (spdk_json_decode_object(params, rpc_nbd_stop_disk_decoders,
  				    SPDK_COUNTOF(rpc_nbd_stop_disk_decoders),
  				    &req)) {
  		SPDK_ERRLOG("spdk_json_decode_object failed\n");
  		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
  						 "spdk_json_decode_object failed");
  		goto out;
  	}
  
  	if (req.nbd_device == NULL) {
  		spdk_jsonrpc_send_error_response(request, -ENODEV, "invalid nbd device");
  		goto out;
  	}
  
  	/* make sure nbd_device is registered */
  	nbd = nbd_disk_find_by_nbd_path(req.nbd_device);
  	if (!nbd) {
  		spdk_jsonrpc_send_error_response(request, -ENODEV, spdk_strerror(ENODEV));
  		goto out;
  	}
  
  	/*
  	 * thd_arg should be freed by created thread
  	 * if thread is created successfully.
  	 */
  	thd_arg = malloc(sizeof(*thd_arg));
  	if (!thd_arg) {
  		SPDK_ERRLOG("could not allocate nbd disconnect thread arg\n");
  		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, "Out of memory");
  		goto out;
  	}
  
  	thd_arg->request = request;
  	thd_arg->nbd = nbd;
  
  	/*
  	 * NBD ioctl of disconnect will block until data are flushed.
  	 * Create separate thread to execute it.
  	 */
  	rc = pthread_create(&tid, NULL, nbd_disconnect_thread, (void *)thd_arg);
  	if (rc != 0) {
  		SPDK_ERRLOG("could not create nbd disconnect thread: %s\n", spdk_strerror(rc));
  		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, spdk_strerror(rc));
  		free(thd_arg);
  		goto out;
  	}
  
  	rc = pthread_detach(tid);
  	if (rc != 0) {
  		SPDK_ERRLOG("could not detach nbd disconnect thread: %s\n", spdk_strerror(rc));
  		goto out;
  	}
  
  out:
  	free_rpc_nbd_stop_disk(&req);
  }
  
  SPDK_RPC_REGISTER("nbd_stop_disk", rpc_nbd_stop_disk, SPDK_RPC_RUNTIME)
  SPDK_RPC_REGISTER_ALIAS_DEPRECATED(nbd_stop_disk, stop_nbd_disk)
  
  static void
  rpc_dump_nbd_info(struct spdk_json_write_ctx *w,
  		  struct spdk_nbd_disk *nbd)
  {
  	spdk_json_write_object_begin(w);
  
  	spdk_json_write_named_string(w, "nbd_device", nbd_disk_get_nbd_path(nbd));
  
  	spdk_json_write_named_string(w, "bdev_name", nbd_disk_get_bdev_name(nbd));
  
  	spdk_json_write_object_end(w);
  }
  
  struct rpc_nbd_get_disks {
  	char *nbd_device;
  };
  
  static void
  free_rpc_nbd_get_disks(struct rpc_nbd_get_disks *r)
  {
  	free(r->nbd_device);
  }
  
  static const struct spdk_json_object_decoder rpc_nbd_get_disks_decoders[] = {
  	{"nbd_device", offsetof(struct rpc_nbd_get_disks, nbd_device), spdk_json_decode_string, true},
  };
  
  static void
  rpc_nbd_get_disks(struct spdk_jsonrpc_request *request,
  		  const struct spdk_json_val *params)
  {
  	struct rpc_nbd_get_disks req = {};
  	struct spdk_json_write_ctx *w;
  	struct spdk_nbd_disk *nbd = NULL;
  
  	if (params != NULL) {
  		if (spdk_json_decode_object(params, rpc_nbd_get_disks_decoders,
  					    SPDK_COUNTOF(rpc_nbd_get_disks_decoders),
  					    &req)) {
  			SPDK_ERRLOG("spdk_json_decode_object failed\n");
  			spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
  							 "spdk_json_decode_object failed");
  			goto invalid;
  		}
  
  		if (req.nbd_device) {
  			nbd = nbd_disk_find_by_nbd_path(req.nbd_device);
  			if (nbd == NULL) {
  				SPDK_ERRLOG("nbd device '%s' does not exist\n", req.nbd_device);
  				spdk_jsonrpc_send_error_response(request, -ENODEV, spdk_strerror(ENODEV));
  				goto invalid;
  			}
  
  			free_rpc_nbd_get_disks(&req);
  		}
  	}
  
  	w = spdk_jsonrpc_begin_result(request);
  	spdk_json_write_array_begin(w);
  
  	if (nbd != NULL) {
  		rpc_dump_nbd_info(w, nbd);
  	} else {
  		for (nbd = nbd_disk_first(); nbd != NULL; nbd = nbd_disk_next(nbd)) {
  			rpc_dump_nbd_info(w, nbd);
  		}
  	}
  
  	spdk_json_write_array_end(w);
  
  	spdk_jsonrpc_end_result(request, w);
  
  	return;
  
  invalid:
  	free_rpc_nbd_get_disks(&req);
  }
  SPDK_RPC_REGISTER("nbd_get_disks", rpc_nbd_get_disks, SPDK_RPC_RUNTIME)
  SPDK_RPC_REGISTER_ALIAS_DEPRECATED(nbd_get_disks, get_nbd_disks)
  