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diff --git a/ioreplay/src/generate/gprocess.h b/ioreplay/src/generate/gprocess.h
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+// Copyright 2018 Mimecast Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef GPROCESS_H
+#define GPROCESS_H
+
+#include "../datas/hmap.h"
+#include "../defaults.h"
+#include "gtask.h"
+#include "generate.h"
+
+// Forward declarations (header include hell)
+struct gtask_s_;
+struct generate_s_;
+
+/**
+ * @brief Virtual process object used for generating .replay file
+ *
+ * An object of this represents a Linux process in generate context.
+ * In Linux every process owns * its own file descriptor table which is
+ * simulated here. Usually, a Linux process re-uses a FD number once not used
+ * anymore (e.g. after a close). However, as we want to increase concurrency
+ * while replaying the I/O we want * to ensure to always use unique file
+ * descriptor IDs for every open. Thats why we use max_mapped_fd to always
+ * map a real FD number to a uniq virtual FD number.
+ */
+typedef struct gprocess_s_ {
+    long pid; /**< The real PID */
+    long mapped_pid; /**< The mapped PID */
+    hmap_s *vfd_map; /**< All virtual file descriptors of that process */
+    hmap_s *fd_map; /**< All mappings from real fd to virtual fd */
+    long max_mapped_fd; /**< The max mapped fd number */
+} gprocess_s;
+
+/**
+ * @brief Creates a new gprocess object
+ *
+ * @param pid The process ID
+ * @param mapped_pid the mapped PID
+ * @return The new gprocess object
+ */
+gprocess_s* gprocess_new(const long pid, const long mapped_pid);
+
+/**
+ * @brief Destroys a gprocess object
+ *
+ * @param gp The gprocess object
+ */
+void gprocess_destroy(gprocess_s *gp);
+
+/**
+ * @brief Creates a new virtual FD from a given real FD number
+ *
+ * In ioreplay we map the real file descriptor (the fd number protocolled in
+ * the.capture file) to a virtual file descriptor (the fd numner written to the
+ * .replay file). The purpose is to increase concurrency of the I/O during
+ * replay. Normally, a process would reuse the same file descriptor number
+ * once closed earlier. However, when replaying we can't reuse the number if
+ * we want to replay the I/O on multiple paths in parallel. Therefore, it is
+ * ensured that the virtual file descriptor number in the .replay file is
+ * always * unique for every open!
+ *
+ * @param gp The process object
+ * @param t The task object (the vfd pointer will be stored to * t->vfd)
+ * @param g The generate object
+ */
+void gprocess_create_vfd_by_realfd(gprocess_s *gp, struct gtask_s_ *t,
+                                   struct generate_s_ *g);
+
+/**
+ * @brief Retrieves a virtual FD from a given real FD number
+ *
+ * @param gp The process object
+ * @param t The task object (the vfd pointer will be stored to * t->vfd)
+ * @return SUCCESS if everything went smothly!
+ */
+status_e gprocess_vfd_by_realfd(gprocess_s *gp, struct gtask_s_ *t);
+
+#endif // GPROCESS_H