--- /dev/null
+/*
+ * LGPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Lesser General Public License
+ * (LGPL) version 2.1 or (at your discretion) any later version.
+ * (LGPL) version 2.1 accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/lgpl-2.1.html
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * LGPL HEADER END
+ */
+/*
+ * lustre/utils/liblustreapi_param.c
+ *
+ * This code handles user interaction with the configuration interface
+ * to the Lustre file system to fine tune it.
+ */
+#include <errno.h>
+#include <stdint.h>
+
+#include <libcfs/util/param.h>
+#include <lustre/lustre_user.h>
+#include <lustre/lustreapi.h>
+#include "lustreapi_internal.h"
+
+/**
+ * return the parameter's path for a specific device type or mountpoint
+ *
+ * \param param the results returned to the caller
+ * \param obd_type Lustre OBD device type
+ *
+ * \param filter filter combined with the type agrument allow the
+ * \param type caller to limit the scope of the search for the
+ * parameter's path. Typical options are search by
+ * Lustre filesystem name or by the path to a file
+ * or directory in the filesystem.
+ *
+ * \param param_name parameter name to fetch
+ *
+ * Using filter and the type argument we can limit the scope of the
+ * search to either the parameter belonging to a specific lustre filesystem
+ * (if it exists) or using a given file or directory path located on a
+ * mounted Lustre filesystem. The last case it can do is a special search
+ * based on exactly what the user passed instead of scanning file paths
+ * or specific file systems.
+ *
+ * If "obd_type" matches a Lustre device then the first matching device
+ * (as with "lctl dl", constrained by \param filter and \param type)
+ * will be used to provide the return value, otherwise the first such
+ * device found will be used.
+ *
+ * Return 0 for success, with the results stored in \param param.
+ * Return -ve value for error.
+ */
+int
+get_lustre_param_path(const char *obd_type, const char *filter,
+ enum param_filter type, const char *param_name,
+ glob_t *param)
+{
+ char pattern[PATH_MAX];
+ int rc = 0;
+
+ if (filter == NULL || obd_type == NULL)
+ return -EINVAL;
+
+ switch (type) {
+ case FILTER_BY_PATH:
+ rc = llapi_search_fsname(filter, pattern);
+ if (rc) {
+ llapi_error(LLAPI_MSG_ERROR, rc,
+ "'%s' is not on a Lustre filesystem",
+ filter);
+ return rc;
+ }
+ if (strlen(pattern) + 3 > sizeof(pattern))
+ return -E2BIG;
+ strncat(pattern, "-*", sizeof(pattern));
+ break;
+ case FILTER_BY_FS_NAME:
+ rc = snprintf(pattern, sizeof(pattern) - 1, "%s-*", filter);
+ if (rc < 0)
+ return rc;
+ else if (rc >= sizeof(pattern))
+ return -EINVAL;
+ rc = 0;
+ break;
+ default:
+ if (strlen(filter) + 1 > sizeof(pattern))
+ return -E2BIG;
+ strncpy(pattern, filter, sizeof(pattern));
+ break;
+ }
+
+ if (param_name != NULL) {
+ if (cfs_get_param_paths(param, "%s/%s/%s",
+ obd_type, pattern, param_name) != 0)
+ rc = -errno;
+ } else {
+ if (cfs_get_param_paths(param, "%s/%s",
+ obd_type, pattern) != 0)
+ rc = -errno;
+ }
+
+ return rc;
+}
+
+/**
+ * return a parameter of a single line value for a specific device type
+ * or mountpoint
+ *
+ * \param obd_type Lustre OBD device type
+ *
+ * \param filter filter combined with the type agruments allow the
+ * \param type caller to limit the scope of the search for the
+ * parameter's path. Typical options are search by
+ * Lustre filesystem name or by the path to a file
+ * or directory in the filesystem.
+ *
+ * \param param_name parameter name to fetch
+ * \param value return buffer for parameter value string
+ * \param val_len size of buffer for return value
+ *
+ * Using filter and the type argument we can limit the scope of the
+ * search to either the parameter belonging to a specific lustre filesystem
+ * (if it exists) or using a given file or directory path located on a
+ * mounted Lustre filesystem. The last case it can do is a special search
+ * based on exactly what the user passed instead of scanning file paths
+ * or specific file systems.
+ *
+ * If "obd_type" matches a Lustre device then the first matching device
+ * (as with "lctl dl", constrained by \param filter and \param type)
+ * will be used to provide the return value, otherwise the first such
+ * device found will be used.
+ *
+ * Return 0 for success, with a NUL-terminated string in \param value.
+ * Return negative errno value for error.
+ */
+int
+get_lustre_param_value(const char *obd_type, const char *filter,
+ enum param_filter type, const char *param_name,
+ char *value, size_t val_len)
+{
+ glob_t param;
+ FILE *fp;
+ int rc;
+
+ rc = get_lustre_param_path(obd_type, filter, type, param_name, ¶m);
+ if (rc != 0)
+ return -ENOENT;
+
+ fp = fopen(param.gl_pathv[0], "r");
+ if (fp == NULL) {
+ rc = -errno;
+ llapi_error(LLAPI_MSG_ERROR, rc, "error: opening '%s'",
+ param.gl_pathv[0]);
+ goto err;
+ }
+
+ if (fgets(value, val_len, fp) == NULL) {
+ if (!feof(fp))
+ rc = -ferror(fp);
+ }
+ fclose(fp);
+err:
+ cfs_free_param_data(¶m);
+
+ return rc;
+}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff