add definition of mem_areas interface

sys/mem_area.h

+#ifndef _SYS_MEM_AREA_H
+#define _SYS_MEM_AREA_H
+
+#include <utils/types.h>
+#include <utils/list.h>
+
+/**
+ * Generic memory-mapping interface, using segmentation-based mapping.
+ */
+
+
+// generic flags :
+// type of area
+#define MEM_AREA_TYPE_FILE		(1<<0)
+#define MEM_AREA_TYPE_ANON		(1<<1)
+
+// some kind of area are allowed to grow
+#define MEM_AREA_MAYGROW		(1<<2)
+// flag used if area grows bottom-up instead of top-down (which is the default)
+#define MEM_AREA_GROW_UP		(1<<3)
+
+
+struct mem_area {
+	int flags;
+
+	// begin address of this area in process address space, and maximum size
+	void *address;
+	size_t max_size;
+
+	// type-specific data (determined by flags)
+	union {
+		struct {
+			// file structure of the file mapped to this area
+			struct file *f;
+
+			// origin's position in the file
+			size_t origin;
+		} file;
+
+		struct {
+			// current size (useful in case of growing areas)
+			size_t size;
+		} anon;
+
+		// device type?
+	};
+
+	struct list_head list;
+};
+
+
+struct process;
+
+/**
+ * Initialize memory area subsystem.
+ */
+void mem_area_init();
+
+
+/**
+ * Return a newly allocated memory area, not initialized.
+ */
+struct mem_area *mem_area_alloc();
+
+
+/**
+ * Look for the given address in given process address space, and return the
+ * corresponding memory area.
+ * NULL is returned if address don't belong to its address space.
+ */
+struct mem_area *mem_area_find(struct process *proc, void *address);
+
+
+/**
+ * Insert a memory area inside the given process' address space.
+ * Return 0 if inserted successfully, negative value else (e.g. overlay on other
+ * areas).
+ */
+int mem_area_insert(struct process *proc, struct mem_area *area);
+
+
+/**
+ * Copy a part of this area content to the given *physical* address.
+ * This function *DO NOT* deal with virtual addresses, and don't check for page
+ * boundaries. The caller should check if given address range still belong
+ * to the appropriate process, and is already "allocated" and usable!
+ * Offset is relative to the beginning of this area.
+ * Return non-zero in error case.
+ */
+int mem_area_copy_raw(struct mem_area *area, size_t offset, void *dest, size_t size);
+
+#endif //_SYS_MEM_AREA_H

sys/process.c

@@ -8,6 +8,7 @@
 #include <utils/bitfield.h>
 #include <interface/fixos/fcntl.h>
 #include <interface/fixos/errno.h>
+#include <sys/mem_areas.h>
 
 #include <loader/elfloader/loader.h>
 #include <fs/vfs_file.h>
@@ -110,6 +111,8 @@ struct process *process_alloc() {
 
 			arch_adrsp_init(& proc->addr_space);
 			proc->dir_list = NULL;
+			INIT_LIST_HEAD(proc->mem_areas);
+
 
 			sigemptyset(& proc->sig_blocked);
 			sigemptyset(& proc->sig_pending);

sys/process.h

@@ -66,6 +66,8 @@ struct process {
 	// virtual memory managing data :
 	struct addr_space addr_space;
 	struct page_dir *dir_list;
+	// address space areas (see sys/mem_area.h)
+	struct list_head mem_areas;
 
 	// files opened by process, index is file descriptor
 	struct file *files[PROCESS_MAX_FILE];