implement memory area manipulation functions

sys/mem_area.c

+#include "mem_area.h"
+#include <sys/process.h>
+#include <utils/pool_alloc.h>
+#include <fs/vfs_file.h>
+#include <utils/log.h>
+
+
+// pool allocation data
+static struct pool_alloc _mem_area_pool = POOL_INIT(struct mem_area);
+
+
+void mem_area_init() {
+	printk(LOG_DEBUG, "mem_area: area/page=%d\n", _mem_area_pool.perpage);
+}
+
+
+struct mem_area *mem_area_alloc() {
+	struct mem_area *ret;
+
+	ret = pool_alloc(&_mem_area_pool);
+	if(ret != NULL) {
+		ret->flags = 0;
+		ret->address = NULL;
+		ret->max_size = 0;
+	}
+
+	return ret;
+}
+
+void mem_area_free(struct mem_area *area) {
+	pool_free(&_mem_area_pool, area);
+}
+
+
+struct mem_area *mem_area_find(struct process *proc, void *address) {
+	// for now, the list is not sorted, so check for each
+	struct list_head *cur;
+	struct mem_area *ret = NULL;
+
+	list_for_each(cur, &(proc->mem_areas)) {
+		// check if address is inside this area
+		struct mem_area *area = container_of(cur, struct mem_area, list);
+		if(address >= area->address && address < (area->address + area->max_size)) {
+			ret = area;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+
+/**
+ * internal function, check if an area is defined in the given address range
+ * Return 0 if this range is empty, 1 if an area exists.
+ */
+static int mem_area_check_range(struct process *proc, void *addr_begin, size_t size) {
+	struct list_head *cur;
+
+	list_for_each(cur, &(proc->mem_areas)) {
+		// check if address range intersects with this area
+		struct mem_area *area = container_of(cur, struct mem_area, list);
+		if(area->address < (addr_begin + size)
+				&& (area->address + area->max_size) > addr_begin)
+			return 1;
+	}
+
+	return 0;
+}
+
+
+int mem_area_insert(struct process *proc, struct mem_area *area) {
+	// check for any overlayed area
+	if(!mem_area_check_range(proc, area->address, area->max_size)) {
+		// not sorted, insert in front
+		list_push_front(& proc->mem_areas, & area->list);
+		return 0;
+	}
+
+	printk(LOG_ERR, "mem_area: unable to insert area (overlay)\n");
+	return -1;
+}
+
+
+int mem_area_copy_raw(struct mem_area *area, size_t offset, void *dest, size_t size) {
+	int ret = -1;
+
+	if(area->flags & MEM_AREA_TYPE_ANON) {
+		// anonymous area, the current implementation do nothing...
+		ret = 0;
+	}
+	else if(area->flags & MEM_AREA_TYPE_FILE) {
+		// file mapped to memory, for now use a generic way to handle them
+		// TODO improve this with map_area_ops struct to allow "override"
+		size_t nbread;
+
+		vfs_lseek(area->file.filep, SEEK_SET, offset);
+		nbread = vfs_read(area->file.filep, dest, size);
+		ret = nbread == size ? 0 : -1;
+	}
+
+	return ret;
+}
+

sys/mem_area.h

@@ -31,7 +31,7 @@ struct mem_area {
 	union {
 		struct {
 			// file structure of the file mapped to this area
-			struct file *f;
+			struct file *filep;
 
 			// origin's position in the file
 			size_t origin;
@@ -61,6 +61,7 @@ void mem_area_init();
  * Return a newly allocated memory area, not initialized.
  */
 struct mem_area *mem_area_alloc();
+void mem_area_free(struct mem_area *area);
 
 
 /**

sys/process.c

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

sys/subdir.mk

@@ -12,7 +12,8 @@ C_SRC_L:= \
 	kdebug.c \
 	sysctl.c \
 	waitqueue.c \
-	tty.c
+	tty.c \
+	mem_area.c
 
 
 CURDIR:=sys