* Fix the mem driver to not always return invalid argument

* Cleanup

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@23140 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/drivers/misc/mem.c

@@ -2,8 +2,6 @@
  * Copyright 2007, Haiku, Inc. All rights reserved.
  * Distributed under the terms of the MIT License.
  */
-
-
 #include <Drivers.h>
 #include <KernelExport.h>
 #include <string.h>
@@ -21,11 +19,11 @@
 static status_t mem_open(const char*, uint32, void**);
 static status_t mem_close(void*);
 static status_t mem_free(void*);
-//static status_t mem_control(void*, uint32, void*, size_t);
 static status_t mem_read(void*, off_t, void*, size_t*);
 static status_t mem_write(void*, off_t, const void*, size_t*);
 
-static area_id mem_map_target(off_t position, size_t len, uint32 protection, void **va);
+static area_id mem_map_target(off_t position, size_t length, uint32 protection,
+	void **virtualAddress);
 
 static const char* mem_name[] = {
 	DEVICE_NAME,
@@ -86,7 +84,6 @@ mem_open(const char* name, uint32 flags, void** cookie)
 {
 	// not really needed.
 	*cookie = NULL;
-
 	return B_OK;
 }
 
@@ -104,87 +101,81 @@ mem_free(void* cookie)
 	return B_OK;
 }
 
-/*
-status_t
-mem_control(void* cookie, uint32 op, void* arg, size_t length)
-{
-	return ENOSYS;
-}
-*/
 
 status_t
 mem_read(void* cookie, off_t position, void* buffer, size_t* numBytes)
 {
-	status_t err;
+	void *virtualAddress;
-	void *va;
 	area_id area;
-	
+
-	/* check perms */
+	/* check permissions */
-	err = EPERM;
+	if (getuid() != 0 && geteuid() != 0) {
-	if (getuid() != 0 && geteuid() != 0)
+		*numBytes = 0;
-		goto err1;
+		return EPERM;
-	err = area = mem_map_target(position, *numBytes, B_READ_AREA, &va);
+	}
-	if (err < 0)
+
-		goto err1;
+	area = mem_map_target(position, *numBytes, B_READ_AREA, &virtualAddress);
-	memcpy(buffer, va, *numBytes);
+	if (area < 0) {
+		*numBytes = 0;
+		return area;
+	}
+
+	memcpy(buffer, virtualAddress, *numBytes);
 	delete_area(area);
 	return B_OK;
-err1:
-	*numBytes = 0;
-	return err;
 }
 
 
 status_t
 mem_write(void* cookie, off_t position, const void* buffer, size_t* numBytes)
 {
-	status_t err;
+	void *virtualAddress;
-	void *va;
 	area_id area;
-	
+
-	/* check perms */
+	/* check permissions */
-	err = EPERM;
+	if (getuid() != 0 && geteuid() != 0) {
-	if (getuid() != 0 && geteuid() != 0)
+		*numBytes = 0;
-		goto err1;
+		return EPERM;
-	err = area = mem_map_target(position, *numBytes, B_WRITE_AREA, &va);
+	}
-	if (err < 0)
+
-		goto err1;
+	area = mem_map_target(position, *numBytes, B_WRITE_AREA, &virtualAddress);
-	memcpy(va, buffer, *numBytes);
+	if (area < 0) {
+		*numBytes = 0;
+		return area;
+	}
+
+	memcpy(virtualAddress, buffer, *numBytes);
 	delete_area(area);
 	return B_OK;
-err1:
-	*numBytes = 0;
-	return err;
 }
 
+
 area_id
-mem_map_target(off_t position, size_t len, uint32 protection, void **va)
+mem_map_target(off_t position, size_t length, uint32 protection,
+	void **virtualAddress)
 {
 	area_id area;
-	void *paddr;
+	void *physicalAddress;
-	void *vaddr;
+	size_t offset;
-	int offset;
 	size_t size;
-	
+
 	/* SIZE_MAX actually but 2G should be enough anyway */
-	if (len > SSIZE_MAX - B_PAGE_SIZE)
+	if (length > SSIZE_MAX - B_PAGE_SIZE)
 		return EINVAL;
-	
+
 	/* the first page address */
-	paddr = (void *)(addr_t)(position & ~((off_t)B_PAGE_SIZE - 1));
+	physicalAddress = (void *)(addr_t)(position & ~((off_t)B_PAGE_SIZE - 1));
+
 	/* offset of target into it */
-	offset = position - (off_t)(addr_t)paddr;
+	offset = position - (off_t)(addr_t)physicalAddress;
+
 	/* size of the whole mapping (page rounded) */
-	size = (offset + len + B_PAGE_SIZE - 1) & ~((size_t)B_PAGE_SIZE - 1);
+	size = (offset + length + B_PAGE_SIZE - 1) & ~((size_t)B_PAGE_SIZE - 1);
-	
+	area = map_physical_memory("mem_driver_temp", physicalAddress, size,
-	area = map_physical_memory("mem_driver_temp",
+		B_ANY_KERNEL_ADDRESS, protection, virtualAddress);
-								paddr, size, B_ANY_KERNEL_ADDRESS,
-								protection, &vaddr);
-	
 	if (area < 0)
 		return area;
-	
+
-	*va = vaddr + offset;
+	*virtualAddress += offset;
-	
+	return area;
-	return EINVAL;
 }