improve memory areas integration

fs/casio_smemfs/file.c

@@ -4,17 +4,21 @@
 #include <fs/inode.h>
 #include <interface/fixos/errno.h>
 #include "smemfs_primitives_ng.h"
+// used for memory areas...
+#include <fs/vfs_file.h>
 
 
 const struct file_operations smemfs_file_operations = {
 	.release = smemfs_release,
 	.read = smemfs_read,
-	.lseek = smemfs_lseek
+	.lseek = smemfs_lseek,
+	.map_area = smemfs_map_area
 };
 
 
 const struct mem_area_ops smemfs_mem_ops = {
-	.area_pagefault = smemfs_area_pagefault
+	.area_pagefault = smemfs_area_pagefault,
+	.area_release = smemfs_area_release
 };
 
 
@@ -140,6 +144,17 @@ off_t smemfs_lseek (struct file *filep, off_t offset, int whence) {
 }
 
 
+
+int smemfs_map_area(struct file *filep, struct mem_area *area) {
+	// not a lot of stuff to do for now...
+	area->ops = &smemfs_mem_ops;
+	area->file.filep = filep;
+	// increase file usage count (mirrored in smemfs_area_release)
+	filep->count++;
+	return 0;
+}
+
+
 union pm_page smemfs_area_pagefault(struct mem_area *area, void *addr_fault) {
 	size_t readsize;
 	void *pmaddr;
@@ -179,10 +194,13 @@ union pm_page smemfs_area_pagefault(struct mem_area *area, void *addr_fault) {
 	return pmpage;
 }
 
-int smemfs_area_resize(struct mem_area *area, const struct mem_area *new_area) {
+/*
+int smemfs_area_resize(struct mem_area *area, size_t new_size) {
 	return -1;
 }
+*/
 
 void smemfs_area_release(struct mem_area *area) {
-
+	// release the file, by closing it at vfs level?
+	vfs_close(area->file.filep);
 }

fs/casio_smemfs/file.h

@@ -24,6 +24,8 @@ off_t smemfs_lseek (struct file *filep, off_t offset, int whence);
 
 
 // memory-mapped operations
+int smemfs_map_area(struct file *filep, struct mem_area *area);
+
 union pm_page smemfs_area_pagefault(struct mem_area *area, void *addr_fault);
 
 int smemfs_area_resize(struct mem_area *area, const struct mem_area *new_area);

fs/file_operations.h

@@ -15,6 +15,8 @@
 
 struct file;
 
+struct mem_area;
+
 struct file_operations {
 	/**
 	 * Release the file opened instance ("close" it).
@@ -47,6 +49,24 @@ struct file_operations {
 	 * data is specific to command and device, may be not used.
 	 */
 	int (*ioctl) (struct file *filep, int cmd, void *data);
+
+
+	/**
+	 * Create a memory map of this object in memory.
+	 * Devices may use it as they want to, for example to provide big buffers
+	 * shared with userland.
+	 * area should be set with all non-private fields having a valid value,
+	 * which is not very well defined...
+	 * At least field ops is not expected to be set, but the interface is not
+	 * well designed for now.
+	 * TODO either use a 'hints' argument with mem_area-like type, or define
+	 * exactly what should be set and what is set by this function itself
+	 *
+	 * NULL if device of filesystem do not implements memory mapped areas.
+	 *
+	 * Return 0 if mapping is accepted, negative value else.
+	 */
+	int (*map_area) (struct file *filep, struct mem_area *area);
 };
 
 #endif //_FS_FILE_OPERATIONS_H

fs/vfs_file.c

@@ -7,6 +7,7 @@
 #include "file_system.h"
 #include "file_operations.h"
 #include "vfs_directory.h"
+#include <sys/mem_area.h>
 
 
 // pool allocation for file struct
@@ -157,3 +158,38 @@ int vfs_fstat(struct file *filep, struct stat *buf) {
 		return -1;
 	}
 }
+
+
+int vfs_map_area(struct file *filep, size_t size, size_t offset, void *address,
+		int flags, size_t infile_size, struct process *proc)
+{
+	int ret = -EINVAL;
+
+	if(filep->op->map_area != NULL) {
+		struct mem_area *area;
+		area = mem_area_alloc();
+		if(area == NULL) {
+			ret = -ENOMEM;
+		}
+		else {
+			// prepare area struct from arguments
+			area->address = address;
+			area->max_size = size;
+			area->flags = flags | MEM_AREA_TYPE_FILE;
+			area->file.base_offset = offset;
+			area->file.infile_size = (flags & MEM_AREA_PARTIAL) ? infile_size : size;
+			area->file.filep = filep;
+			
+			ret = filep->op->map_area(filep, area);
+			if(ret == 0) {
+				ret = mem_area_insert(proc, area);
+			}
+			else {
+				// failed, free area (do not *release* it, free directly)
+				mem_area_free(area);
+			}
+		}
+	}
+	
+	return ret;
+}

fs/vfs_file.h

@@ -90,4 +90,18 @@ int vfs_ioctl(struct file *filep, int cmd, void *data);
 int vfs_fstat(struct file *filep, struct stat *buf);
 
 
+struct process;
+
+/**
+ * Map size bytes of the object in memory, from given offset, to given address
+ * in the address space of a given process.
+ * Area permissions, and additionnal flags, may be provided, using constants
+ * from sys/mem_area.h
+ * from_file is important only if flag contains MEM_AREA_PARTIAL
+ *
+ * TODO make a 'hints' structure to reduce number of arguments?
+ */
+int vfs_map_area(struct file *filep, size_t size, size_t offset, void *address,
+		int flags, size_t infile_size, struct process *proc);
+
 #endif //_FS_VFS_FILE_H

interface/fixos/errno.h

@@ -24,6 +24,7 @@
 #define ESRCH			16
 #define EACCES			17
 #define EPERM			18
+#define ENOMEM			19
 
 
 #endif //_FIXOS_INTERFACE_ERRNO_H

loader/elfloader/loader.c

@@ -46,8 +46,7 @@ int elfloader_load(struct file *filep, struct process *dest) {
 
 		// set user stack (the size used *is* a maximum, not the allocated one)
 		struct mem_area *user_stack;
-		user_stack = mem_area_alloc();
-		mem_area_set_anon(user_stack, (void*)(ARCH_UNEWPROC_DEFAULT_STACK 
+		user_stack = mem_area_make_anon((void*)(ARCH_UNEWPROC_DEFAULT_STACK 
 				- PROCESS_DEFAULT_STACK_SIZE), PROCESS_DEFAULT_STACK_SIZE);
 		mem_area_insert(dest, user_stack);
 
@@ -192,24 +191,12 @@ int elfloader_load_segment(struct file *filep, void *offset,
 		const struct elf_prog_header *ph, struct process *dest)
 {
 	if(ph->vaddr % PM_PAGE_BYTES == 0) {
-		// TODO replace with appropriate mem_area helper!
-		struct mem_area *area;
-
-		area = mem_area_alloc();
-		filep->count ++;
-		area->flags = MEM_AREA_TYPE_FILE | MEM_AREA_PARTIAL;
-		area->file.filep = filep;
-		area->file.base_offset = ph->offset;
-		area->max_size = ph->memsz;
-		// allow to fill with 0 any 0-initialized sections (like .bss)
-		area->file.infile_size = ph->filesz;
-		area->address = offset + ph->vaddr;
-		// FIXME temporary
-		area->ops = & smemfs_mem_ops;
-		
-		mem_area_insert(dest, area);
-	
-		return 0;
+		int prot;
+
+		// TODO use real permissions from ELF
+		prot = MEM_AREA_PROT_R | MEM_AREA_PROT_W | MEM_AREA_PROT_X;
+		return vfs_map_area(filep, ph->memsz, ph->offset, offset + ph->vaddr,
+				MEM_AREA_PARTIAL | prot, ph->filesz, dest);
 	}
 	else {
 		printk(LOG_ERR, "elfloader: segment begin not page-aligned.\n");

sys/mem_area.c

@@ -13,12 +13,13 @@ static struct pool_alloc _mem_area_pool = POOL_INIT(struct mem_area);
 // anonymous area operations
 static union pm_page anon_area_pagefault(struct mem_area *area, void *addr_fault);
 
-static int anon_area_resize(struct mem_area *area, const struct mem_area *new_area);
+static int anon_area_resize(struct mem_area *area, size_t new_size);
 
-static void anon_area_release(struct mem_area *area);
+//static void anon_area_release(struct mem_area *area);
 
-static struct mem_area_ops _anon_area_ops = {
-	.area_pagefault = anon_area_pagefault
+static const struct mem_area_ops _anon_area_ops = {
+	.area_pagefault = anon_area_pagefault,
+	.area_resize = anon_area_resize
 };
 
 
@@ -47,12 +48,19 @@ void mem_area_free(struct mem_area *area) {
 
 
 
-void mem_area_set_anon(struct mem_area *area, void *vmaddr, size_t size) {
-	// nothing more, for now...
-	area->flags = MEM_AREA_TYPE_ANON;
-	area->address = vmaddr;
-	area->max_size = size;
-	area->ops = &_anon_area_ops;
+struct mem_area *mem_area_make_anon(void *vmaddr, size_t size) {
+	struct mem_area *area;
+	
+	area = mem_area_alloc();
+	if(area != NULL) {
+		// nothing more, for now...
+		area->flags = MEM_AREA_TYPE_ANON | MEM_AREA_PROT_R | MEM_AREA_PROT_W
+			| MEM_AREA_PROT_X;
+		area->address = vmaddr;
+		area->max_size = size;
+		area->ops = &_anon_area_ops;
+	}
+	return area;
 }
 
 
@@ -190,3 +198,12 @@ static union pm_page anon_area_pagefault(struct mem_area *area, void *addr_fault
 
 	return pmpage;
 }
+
+
+static int anon_area_resize(struct mem_area *area, size_t new_size) {
+	// handle only for debug purpose
+	printk(LOG_DEBUG, "mem_area: resize area @%p (%d->%d)\n", area->address,
+			area->max_size, new_size);
+	area->max_size = new_size;
+	return 0;
+}

sys/mem_area.h

@@ -34,7 +34,7 @@ struct mem_area {
 	size_t max_size;
 
 	// callback functions to manage this area
-	struct mem_area_ops *ops;
+	const struct mem_area_ops *ops;
 
 	// type-specific data (determined by flags)
 	union {
@@ -108,15 +108,23 @@ void mem_area_init();
 
 /**
  * Return a newly allocated memory area, not initialized.
+ * This function is mainly designed for helper usage.
  */
 struct mem_area *mem_area_alloc();
+
+/**
+ * Free an allocated memory area, *without* any clean checkup!
+ * Should not be used unless you are sure the given area is not valid,
+ * or already clean.
+ * Use mem_area_release() in other cases!
+ */
 void mem_area_free(struct mem_area *area);
 
 
 /**
- * Helper to set an allocated memory area as an anonymous area.
+ * Helper to create an anonymous memory area, at given address.
  */
-void mem_area_set_anon(struct mem_area *area, void *vmaddr, size_t size);
+struct mem_area *mem_area_make_anon(void *vmaddr, size_t size);
 
 
 /**
@@ -152,6 +160,17 @@ extern inline union pm_page mem_area_pagefault(struct mem_area *area,
 	}
 }
 
+
+/**
+ * Release, and free if necessary, the given area, after calling the
+ * implementation-specific release callback if any.
+ */
+extern inline void mem_area_release(struct mem_area *area) {
+	if(area->ops != NULL && area->ops->area_release != NULL)
+		area->ops->area_release(area);
+	mem_area_free(area);
+}
+
 /**
  * Resize an area to the given new_size.
  * If size is decreased and some memory pages associated with corresponding

sys/process.c

@@ -204,7 +204,7 @@ void process_terminate(struct process *proc, int status) {
 	while(cur_area != & proc->mem_areas) {
 		struct list_head *next_area = cur_area->next;
 		struct mem_area *area = container_of(cur_area, struct mem_area, list);
-		mem_area_free(area);
+		mem_area_release(area);
 		cur_area = next_area;
 	}
 	INIT_LIST_HEAD(& proc->mem_areas);
@@ -470,7 +470,7 @@ int sys_execve(const char *filename, char *const argv[], char *const envp[]) {
 		while(cur_area != & cur->mem_areas) {
 			struct list_head *next_area = cur_area->next;
 			struct mem_area *area = container_of(cur_area, struct mem_area, list);
-			mem_area_free(area);
+			mem_area_release(area);
 			cur_area = next_area;
 		}
 		INIT_LIST_HEAD(& cur->mem_areas);
@@ -557,13 +557,12 @@ void *sys_sbrk(int incr) {
 		void *real_brk;
 		size_t brk_align;
 
-		heap = mem_area_alloc();
-
 		// create heap area, using initial location rounded to page align
 		brk_align = ((size_t)cur->initial_brk) % PM_PAGE_BYTES;
 		real_brk = brk_align == 0 ? cur->initial_brk
 			: cur->initial_brk + (PM_PAGE_BYTES - brk_align);
-		mem_area_set_anon(heap, real_brk, 0);
+
+		heap = mem_area_make_anon(real_brk, 0);
 		mem_area_insert(cur, heap);
 
 		cur->heap_area = heap;
@@ -578,7 +577,8 @@ void *sys_sbrk(int incr) {
 		size_t new_size;
 
 		printk(LOG_DEBUG, "sbrk: incr=%d\n", incr);
-		new_size = -incr > heap->max_size ? 0 : heap->max_size + incr;
+		// avoid negative size (size_t is unsigned, be careful)
+		new_size = (incr < 0 && -incr > heap->max_size) ? 0 : heap->max_size + incr;
 		mem_area_resize(heap, new_size, cur);
 
 		return ret;