Added a public domain malloc temporarily.

More changes to fs0, still improvising.

tasks/fs0/include/fs.h

@@ -59,7 +59,7 @@ struct dentry {
 	struct dentry *parent;		/* Parent dentry */
 	struct list_head child;		/* List of dentries with same parent */
 	struct list_head children;	/* List of children dentries */
-	struct list_head dref_list;	/* For vnode's dirent reference list */
+	struct list_head vref;		/* For vnode's dirent reference list */
 	struct vnode *vnode;		/* The vnode associated with dirent */
 	struct dentry_ops ops;
 };

tasks/fs0/include/malloc.h

@@ -0,0 +1,7 @@
+#ifndef __PRIVATE_MALLOC_H__
+#define __PRIVATE_MALLOC_H__
+
+void *kmalloc(size_t size);
+void kfree(void *blk);
+
+#endif /*__PRIVATE_MALLOC_H__ */

tasks/fs0/src/bootfs/bootfs.c

@@ -1,24 +1,90 @@
 /*
- * An imaginary filesystem for reading the in-memory
- * server tasks loaded out of the initial elf executable.
+ * A pseudo-filesystem for reading the in-memory
+ * server tasks loaded from the initial elf executable.
  *
  * Copyright (C) 2007, 2008 Bahadir Balban
  */
 #include <fs.h>
 #include <l4/lib/list.h>
+#include <malloc.h>
+
+struct dentry *bootfs_dentry_lookup(struct dentry *d, char *dname)
+{
+	struct dentry *this;
+
+	list_for_each_entry(this, child, &d->children) {
+		if (this->compare(this, dname))
+			return this;
+	}
+	return 0;
+}
+
+struct dentry *path_lookup(struct superblock *sb, char *pathstr)
+{
+	char *dname;
+	char *splitpath;
+	struct dentry *this, *next;
+
+	/* First dentry is root */
+	this = sb->root;
+
+	/* Get next path component from path string */
+	dname = path_next_dentry_name(pathstr);
+
+	if (!this->compare(dname))
+		return;
+
+	while(!(dname = path_next_dentry_name(pathstr))) {
+		if ((d = this->lookup(this, dname)))
+			return 0;
+	}
+}
 
 /*
- * These are preallocated structures for forging a filesystem tree
- * from the elf loaded server segments available from kdata info.
+ * This creates a pseudo-filesystem tree from the loaded
+ * server elf images whose information is available from
+ * initdata.
  */
-#define BOOTFS_IMG_MAX					10
-struct vnode bootfs_vnode[BOOTFS_IMG_MAX];
-struct dentry bootfs_dentry[BOOTFS_IMG_MAX];
-struct file bootfs_file[BOOTFS_IMG_MAX];
+void bootfs_populate(struct initdata *initdata, struct superblock *sb)
+{
+	struct bootdesc *bd = initdata->bootdesc;
+	struct svc_image *img;
+	struct dentry *d;
+	struct vnode *v;
+	struct file *f;
 
-/* These are for the root */
-struct dentry bootfs_root;
-struct vnode bootfs_rootvn;
+	for (int i = 0; i < bd->total_images; i++) {
+		img = &bd->images[i];
+
+		d = malloc(sizeof(struct dentry));
+		v = malloc(sizeof(struct vnode));
+		f = malloc(sizeof(struct file));
+
+		/* Initialise dentry for image */
+		d->refcnt = 0;
+		d->vnode = v;
+		d->parent = sb->root;
+		strncpy(d->name, img->name, VFS_DENTRY_NAME_MAX);
+		INIT_LIST_HEAD(&d->child);
+		INIT_LIST_HEAD(&d->children);
+		list_add(&d->child, &sb->root->children);
+
+		/* Initialise vnode for image */
+		v->refcnt = 0;
+		v->id = img->phys_start;
+		v->size = img->phys_end - img->phys_start;
+		INIT_LIST_HEAD(&v->dirents);
+		list_add(&d->v_ref, &v->dirents);
+
+		/* Initialise file struct for image */
+		f->refcnt = 0;
+		f->dentry = d;
+
+		img_d++;
+		img_vn++;
+		img_f++;
+	}
+}
 
 void bootfs_init_root(struct dentry *r)
 {
@@ -43,8 +109,8 @@ void bootfs_init_root(struct dentry *r)
 
 struct superblock *bootfs_init_sb(struct superblock *sb)
 {
-	sb->root = &bootfs_root;
-	sb->root->vnode = &bootfs_rootvn;
+	sb->root = malloc(sizeof(struct dentry));
+	sb->root->vnode = malloc(sizeof(struct vnode));
 
 	bootfs_init_root(&sb->root);
 
@@ -75,8 +141,7 @@ struct file_system_type bootfs_type = {
 
 void init_bootfs()
 {
-	struct superblock *sb;
+	bootfs_init_sb(&bootfs_sb);
 
-	sb = bootfs_type.get_sb();
+	bootfs_populate(&bootfs_sb);
 }
-

tasks/fs0/src/malloc.c

@@ -0,0 +1,408 @@
+/*****************************************************************************
+Simple malloc
+Chris Giese <geezer@execpc.com>	http://www.execpc.com/~geezer
+Release date: Oct 30, 2002
+This code is public domain (no copyright).
+You can do whatever you want with it.
+
+Features:
+- First-fit
+- free() coalesces adjacent free blocks
+- Uses variable-sized heap, enlarged with kbrk()/sbrk() function
+- Does not use mmap()
+- Can be easily modified to use fixed-size heap
+- Works with 16- or 32-bit compilers
+
+Build this program with either of the two main() functions, then run it.
+Messages that indicate a software error will contain three asterisks (***).
+*****************************************************************************/
+#include <string.h> /* memcpy(), memset() */
+#include <stdio.h> /* printf() */
+
+#define	_32BIT	1
+
+/* use small (32K) heap for 16-bit compilers,
+large (500K) heap for 32-bit compilers */
+#if defined(_32BIT)
+#define	HEAP_SIZE	500000uL
+#else
+#define	HEAP_SIZE	32768u
+#endif
+
+#define	MALLOC_MAGIC	0x6D92	/* must be < 0x8000 */
+
+typedef struct _malloc		/* Turbo C	DJGPP */
+{
+	size_t size;		/* 2 bytes	 4 bytes */
+	struct _malloc *next;	/* 2 bytes	 4 bytes */
+	unsigned magic : 15;	/* 2 bytes total 4 bytes total */
+	unsigned used : 1;
+} malloc_t;		/* total   6 bytes	12 bytes */
+
+static char *g_heap_bot, *g_kbrk, *g_heap_top;
+/*****************************************************************************
+*****************************************************************************/
+static void dump_heap(void)
+{
+	unsigned blks_used = 0, blks_free = 0;
+	size_t bytes_used = 0, bytes_free = 0;
+	malloc_t *m;
+	int total;
+
+	printf("===============================================\n");
+	for(m = (malloc_t *)g_heap_bot; m != NULL; m = m->next)
+	{
+		printf("blk %5p: %6u bytes %s\n", m,
+			m->size, m->used ? "used" : "free");
+		if(m->used)
+		{
+			blks_used++;
+			bytes_used += m->size;
+		}
+		else
+		{
+			blks_free++;
+			bytes_free += m->size;
+		}
+	}
+	printf("blks:  %6u used, %6u free, %6u total\n", blks_used,
+		blks_free, blks_used + blks_free);
+	printf("bytes: %6u used, %6u free, %6u total\n", bytes_used,
+		bytes_free, bytes_used + bytes_free);
+	printf("g_heap_bot=0x%p, g_kbrk=0x%p, g_heap_top=0x%p\n",
+		g_heap_bot, g_kbrk, g_heap_top);
+	total = (bytes_used + bytes_free) +
+			(blks_used + blks_free) * sizeof(malloc_t);
+	if(total != g_kbrk - g_heap_bot)
+		printf("*** some heap memory is not accounted for\n");
+	printf("===============================================\n");
+}
+/*****************************************************************************
+POSIX sbrk() looks like this
+	void *sbrk(int incr);
+Mine is a bit different so I can signal the calling function
+if more memory than desired was allocated (e.g. in a system with paging)
+If your kbrk()/sbrk() always allocates the amount of memory you ask for,
+this code can be easily changed.
+
+			int brk(	void *sbrk(		void *kbrk(
+function		 void *adr);	 int delta);		 int *delta);
+----------------------	------------	------------		-------------
+POSIX?			yes		yes			NO
+return value if error	-1		-1			NULL
+get break value		.		sbrk(0)			int x=0; kbrk(&x);
+set break value to X	brk(X)		sbrk(X - sbrk(0))	int x=X, y=0; kbrk(&x) - kbrk(&y);
+enlarge heap by N bytes	.		sbrk(+N)		int x=N; kbrk(&x);
+shrink heap by N bytes	.		sbrk(-N)		int x=-N; kbrk(&x);
+can you tell if you're
+  given more memory
+  than you wanted?	no		no			yes
+*****************************************************************************/
+static void *kbrk(int *delta)
+{
+	static char heap[HEAP_SIZE];
+/**/
+	char *new_brk, *old_brk;
+
+/* heap doesn't exist yet */
+	if(g_heap_bot == NULL)
+	{
+		g_heap_bot = g_kbrk = heap;
+		g_heap_top = g_heap_bot + HEAP_SIZE;
+	}
+	new_brk = g_kbrk + (*delta);
+/* too low: return NULL */
+	if(new_brk < g_heap_bot)
+		return NULL;
+/* too high: return NULL */
+	if(new_brk >= g_heap_top)
+		return NULL;
+/* success: adjust brk value... */
+	old_brk = g_kbrk;
+	g_kbrk = new_brk;
+/* ...return actual delta... (for this sbrk(), they are the same)
+	(*delta) = (*delta); */
+/* ...return old brk value */
+	return old_brk;
+}
+/*****************************************************************************
+kmalloc() and kfree() use g_heap_bot, but not g_kbrk nor g_heap_top
+*****************************************************************************/
+void *kmalloc(size_t size)
+{
+	unsigned total_size;
+	malloc_t *m, *n;
+	int delta;
+
+	if(size == 0)
+		return NULL;
+	total_size = size + sizeof(malloc_t);
+/* search heap for free block (FIRST FIT) */
+	m = (malloc_t *)g_heap_bot;
+/* g_heap_bot == 0 == NULL if heap does not yet exist */
+	if(m != NULL)
+	{
+		if(m->magic != MALLOC_MAGIC)
+//			panic("kernel heap is corrupt in kmalloc()");
+		{
+			printf("*** kernel heap is corrupt in kmalloc()\n");
+			return NULL;
+		}
+		for(; m->next != NULL; m = m->next)
+		{
+			if(m->used)
+				continue;
+/* size == m->size is a perfect fit */
+			if(size == m->size)
+				m->used = 1;
+			else
+			{
+/* otherwise, we need an extra sizeof(malloc_t) bytes for the header
+of a second, free block */
+				if(total_size > m->size)
+					continue;
+/* create a new, smaller free block after this one */
+				n = (malloc_t *)((char *)m + total_size);
+				n->size = m->size - total_size;
+				n->next = m->next;
+				n->magic = MALLOC_MAGIC;
+				n->used = 0;
+/* reduce the size of this block and mark it used */
+				m->size = size;
+				m->next = n;
+				m->used = 1;
+			}
+			return (char *)m + sizeof(malloc_t);
+		}
+	}
+/* use kbrk() to enlarge (or create!) heap */
+	delta = total_size;
+	n = kbrk(&delta);
+/* uh-oh */
+	if(n == NULL)
+		return NULL;
+	if(m != NULL)
+		m->next = n;
+	n->size = size;
+	n->magic = MALLOC_MAGIC;
+	n->used = 1;
+/* did kbrk() return the exact amount of memory we wanted?
+cast to make "gcc -Wall -W ..." shut the hell up */
+	if((int)total_size == delta)
+		n->next = NULL;
+	else
+	{
+/* it returned more than we wanted (it will never return less):
+create a new, free block */
+		m = (malloc_t *)((char *)n + total_size);
+		m->size = delta - total_size - sizeof(malloc_t);
+		m->next = NULL;
+		m->magic = MALLOC_MAGIC;
+		m->used = 0;
+
+		n->next = m;
+	}
+	return (char *)n + sizeof(malloc_t);
+}
+/*****************************************************************************
+*****************************************************************************/
+void kfree(void *blk)
+{
+	malloc_t *m, *n;
+
+/* get address of header */
+	m = (malloc_t *)((char *)blk - sizeof(malloc_t));
+	if(m->magic != MALLOC_MAGIC)
+//		panic("attempt to kfree() block at 0x%p "
+//			"with bad magic value", blk);
+	{
+		printf("*** attempt to kfree() block at 0x%p "
+			"with bad magic value\n", blk);
+		return;
+	}
+/* find this block in the heap */
+	n = (malloc_t *)g_heap_bot;
+	if(n->magic != MALLOC_MAGIC)
+//		panic("kernel heap is corrupt in kfree()");
+	{
+		printf("*** kernel heap is corrupt in kfree()\n");
+		return;
+	}
+	for(; n != NULL; n = n->next)
+	{
+		if(n == m)
+			break;
+	}
+/* not found? bad pointer or no heap or something else? */
+	if(n == NULL)
+//		panic("attempt to kfree() block at 0x%p "
+//			"that is not in the heap", blk);
+	{
+		printf("*** attempt to kfree() block at 0x%p "
+			"that is not in the heap\n", blk);
+		return;
+	}
+/* free the block */
+	m->used = 0;
+/* coalesce adjacent free blocks
+Hard to spell, hard to do */
+	for(m = (malloc_t *)g_heap_bot; m != NULL; m = m->next)
+	{
+		while(!m->used && m->next != NULL && !m->next->used)
+		{
+/* resize this block */
+			m->size += sizeof(malloc_t) + m->next->size;
+/* merge with next block */
+			m->next = m->next->next;
+		}
+	}
+}
+/*****************************************************************************
+*****************************************************************************/
+void *krealloc(void *blk, size_t size)
+{
+	void *new_blk;
+	malloc_t *m;
+
+/* size == 0: free block */
+	if(size == 0)
+	{
+		if(blk != NULL)
+			kfree(blk);
+		new_blk = NULL;
+	}
+	else
+	{
+/* allocate new block */
+		new_blk = kmalloc(size);
+/* if allocation OK, and if old block exists, copy old block to new */
+		if(new_blk != NULL && blk != NULL)
+		{
+			m = (malloc_t *)((char *)blk - sizeof(malloc_t));
+			if(m->magic != MALLOC_MAGIC)
+//				panic("attempt to krealloc() block at "
+//					"0x%p with bad magic value", blk);
+			{
+				printf("*** attempt to krealloc() block at "
+					"0x%p with bad magic value\n", blk);
+				return NULL;
+			}
+/* copy minimum of old and new block sizes */
+			if(size > m->size)
+				size = m->size;
+			memcpy(new_blk, blk, size);
+/* free the old block */
+			kfree(blk);
+		}
+	}
+	return new_blk;
+}
+/*****************************************************************************
+*****************************************************************************/
+
+#if 0
+
+#include <stdlib.h> /* rand() */
+
+
+#define	SLOTS	17
+
+int main(void)
+{
+	unsigned lifetime[SLOTS];
+	void *blk[SLOTS];
+	int i, j, k;
+
+	dump_heap();
+	memset(lifetime, 0, sizeof(lifetime));
+	memset(blk, 0, sizeof(blk));
+	for(i = 0; i < 1000; i++)
+	{
+		printf("Pass %6u\n", i);
+		for(j = 0; j < SLOTS; j++)
+		{
+/* age the block */
+			if(lifetime[j] != 0)
+			{
+				(lifetime[j])--;
+				continue;
+			}
+/* too old; free it */
+			if(blk[j] != NULL)
+			{
+				kfree(blk[j]);
+				blk[j] = NULL;
+			}
+/* alloc new block of random size
+Note that size_t==unsigned, but kmalloc() uses integer math,
+so block size must be positive integer */
+#if defined(_32BIT)
+			k = rand() % 40960 + 1;
+#else
+			k = rand() % 4096 + 1;
+#endif
+			blk[j] = kmalloc(k);
+			if(blk[j] == NULL)
+				printf("failed to alloc %u bytes\n", k);
+			else
+/* give it a random lifetime 0-20 */
+				lifetime[j] = rand() % 21;
+		}
+	}
+/* let's see what we've wrought */
+	printf("\n\n");
+	dump_heap();
+/* free everything */
+	for(j = 0; j < SLOTS; j++)
+	{
+		if(blk[j] != NULL)
+		{
+			kfree(blk[j]);
+			blk[j] = NULL;
+		}
+		(lifetime[j]) = 0;
+	}
+/* after all that, we should have a single, unused block */
+	dump_heap();
+	return 0;
+}
+/*****************************************************************************
+*****************************************************************************/
+
+int main(void)
+{
+	void *b1, *b2, *b3;
+
+	dump_heap();
+
+	b1 = kmalloc(42);
+	dump_heap();
+
+	b2 = kmalloc(23);
+	dump_heap();
+
+	b3 = kmalloc(7);
+	dump_heap();
+
+	b2 = krealloc(b2, 24);
+	dump_heap();
+
+	kfree(b1);
+	dump_heap();
+
+	b1 = kmalloc(5);
+	dump_heap();
+
+	kfree(b2);
+	dump_heap();
+
+	kfree(b3);
+	dump_heap();
+
+	kfree(b1);
+	dump_heap();
+
+	return 0;
+}
+#endif
+