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Kernel: add very WIP implementation of initrd

This commit is contained in:
g1n 2021-09-14 17:21:46 +03:00
parent 7b912d6abe
commit e84e4719a4
12 changed files with 1083 additions and 5 deletions
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57
fsgenerator.c Normal file
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@ -0,0 +1,57 @@
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
struct initrd_header
{
unsigned char magic; // The magic number is there to check for consistency.
char name[64];
unsigned int offset; // Offset in the initrd the file starts.
unsigned int length; // Length of the file.
};
int main(char argc, char **argv)
{
int nheaders = (argc-1)/2;
struct initrd_header headers[64];
printf("size of header: %d\n", sizeof(struct initrd_header));
unsigned int off = sizeof(struct initrd_header) * 64 + sizeof(int);
int i;
for(i = 0; i < nheaders; i++)
{
printf("writing file %s->%s at 0x%x\n", argv[i*2+1], argv[i*2+2], off);
strcpy(headers[i].name, argv[i*2+2]);
headers[i].offset = off;
FILE *stream = fopen(argv[i*2+1], "r");
if(stream == 0)
{
printf("Error: file not found: %s\n", argv[i*2+1]);
return 1;
}
fseek(stream, 0, SEEK_END);
headers[i].length = ftell(stream);
off += headers[i].length;
fclose(stream);
headers[i].magic = 0xBF;
}
FILE *wstream = fopen("./initrd.img", "w");
unsigned char *data = (unsigned char *)malloc(off);
fwrite(&nheaders, sizeof(int), 1, wstream);
fwrite(headers, sizeof(struct initrd_header), 64, wstream);
for(i = 0; i < nheaders; i++)
{
FILE *stream = fopen(argv[i*2+1], "r");
unsigned char *buf = (unsigned char *)malloc(headers[i].length);
fread(buf, 1, headers[i].length, stream);
fwrite(buf, 1, headers[i].length, wstream);
fclose(stream);
free(buf);
}
fclose(wstream);
free(data);
return 0;
}

2
iso.sh
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@ -7,9 +7,11 @@ mkdir -p isodir/boot
mkdir -p isodir/boot/grub
cp sysroot/boot/orion.kernel isodir/boot/orion.kernel
cp sysroot/boot/initrd.img isodir/boot/initrd.img
cat > isodir/boot/grub/grub.cfg << EOF
menuentry "orion" {
multiboot /boot/orion.kernel
module /boot/initrd.img
}
EOF
grub-mkrescue -o orion.iso isodir

27
kernel/kernel/early_kernel.c
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@ -1,4 +1,5 @@
#include <stdint.h>
#include <assert.h>
#include <kernel/tty.h>
#include <stdio.h>
@ -8,8 +9,14 @@
//#include "timer.c"
#include "keyboard.c"
#include "paging.h"
//#include "fs.c"
#include "initrd.c"
#include "multiboot.h"
void kernel_early_main(void) {
extern heap_t *kheap;
extern fs_node_t *fs_root; // The root of the filesystem.
void kernel_early_main(struct multiboot *mboot_ptr) {
gdt_init();
init_serial();
serial_printf("gdt initialized!\n");
@ -17,9 +24,25 @@ void kernel_early_main(void) {
serial_printf("idt initialized!\n");
//init_timer(50); // Initialise timer to 50Hz
//serial_printf("timer initialized!\n");
// Find the location of our initial ramdisk.
//assert(mboot_ptr->mods_count > 0);
if (!(mboot_ptr->mods_count > 0)) {
serial_printf("PANIC!!");
}
uint32_t initrd_location = *((uint32_t*)mboot_ptr->mods_addr);
uint32_t initrd_end = *(uint32_t*)(mboot_ptr->mods_addr+4);
// Don't trample our module with placement accesses, please!
placement_address = initrd_end;
init_paging();
serial_printf("paging initialized!\n");
//open_fs(fs_root, 1, 0);
fs_root = init_initrd(initrd_location);
serial_printf("initrd!\n");
init_keyboard();
serial_printf("keyboard initialized!\n");
terminal_initialize();
terminal_initialize(); // FIXME
int a = kmalloc(23); // FIXME
free(a, kheap);
}

106
kernel/kernel/fs.c Normal file
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@ -0,0 +1,106 @@
typedef uint32_t (*read_type_t)(struct fs_node*,uint32_t,uint32_t,uint8_t*);
typedef uint32_t (*write_type_t)(struct fs_node*,uint32_t,uint32_t,uint8_t*);
typedef void (*open_type_t)(struct fs_node*);
typedef void (*close_type_t)(struct fs_node*);
typedef struct dirent * (*readdir_type_t)(struct fs_node*,uint32_t);
typedef struct fs_node * (*finddir_type_t)(struct fs_node*,char *name);
typedef struct fs_node
{
char name[128]; // The filename.
uint32_t mask; // The permissions mask.
uint32_t uid; // The owning user.
uint32_t gid; // The owning group.
uint32_t flags; // Includes the node type. See #defines above.
uint32_t inode; // This is device-specific - provides a way for a filesystem to identify files.
uint32_t length; // Size of the file, in bytes.
uint32_t impl; // An implementation-defined number.
read_type_t read;
write_type_t write;
open_type_t open;
close_type_t close;
readdir_type_t readdir;
finddir_type_t finddir;
struct fs_node *ptr; // Used by mountpoints and symlinks.
} fs_node_t;
struct dirent // One of these is returned by the readdir call, according to POSIX.
{
char name[128]; // Filename.
uint32_t ino; // Inode number. Required by POSIX.
};
#define FS_FILE 0x01
#define FS_DIRECTORY 0x02
#define FS_CHARDEVICE 0x03
#define FS_BLOCKDEVICE 0x04
#define FS_PIPE 0x05
#define FS_SYMLINK 0x06
#define FS_MOUNTPOINT 0x08
//extern fs_node_t *fs_root; // The root of the filesystem.
// Standard read/write/open/close functions. Note that these are all suffixed with
// _fs to distinguish them from the read/write/open/close which deal with file descriptors
// not file nodes.
//uint32_t read_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
//uint32_t write_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer);
//void open_fs(fs_node_t *node, uint8_t read, uint8_t write);
//void close_fs(fs_node_t *node);
//struct dirent *readdir_fs(fs_node_t *node, uint32_t index);
//fs_node_t *finddir_fs(fs_node_t *node, char *name);
fs_node_t *fs_root = 0; // The root of the filesystem.
uint32_t read_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer)
{
// Has the node got a read callback?
if (node->read != 0)
return node->read(node, offset, size, buffer);
else
return 0;
}
uint32_t write_fs(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer)
{
// Has the node got a write callback?
if (node->write != 0)
return node->write(node, offset, size, buffer);
else
return 0;
}
void open_fs(fs_node_t *node, uint8_t read, uint8_t write)
{
// Has the node got an open callback?
if (node->open != 0)
return node->open(node);
}
void close_fs(fs_node_t *node)
{
// Has the node got a close callback?
if (node->close != 0)
return node->close(node);
}
struct dirent *readdir_fs(fs_node_t *node, uint32_t index)
{
// Is the node a directory, and does it have a callback?
if ( (node->flags&0x7) == FS_DIRECTORY &&
node->readdir != 0 )
return node->readdir(node, index);
else
return 0;
}
fs_node_t *finddir_fs(fs_node_t *node, char *name)
{
// Is the node a directory, and does it have a callback?
if ( (node->flags&0x7) == FS_DIRECTORY &&
node->finddir != 0 )
return node->finddir(node, name);
else
return 0;
}

132
kernel/kernel/initrd.c Normal file
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@ -0,0 +1,132 @@
#include <string.h>
#include "fs.c"
#include "kheap.c"
typedef struct
{
uint32_t nfiles; // The number of files in the ramdisk.
} initrd_header_t;
typedef struct
{
uint8_t magic; // Magic number, for error checking.
int8_t name[64]; // Filename.
uint32_t offset; // Offset in the initrd that the file starts.
uint32_t length; // Length of the file.
} initrd_file_header_t;
// Initialises the initial ramdisk. It gets passed the address of the multiboot module,
// and returns a completed filesystem node.
fs_node_t *initialise_initrd(uint32_t location);
initrd_header_t *initrd_header; // The header.
initrd_file_header_t *file_headers; // The list of file headers.
fs_node_t *initrd_root; // Our root directory node.
fs_node_t *initrd_dev; // We also add a directory node for /dev, so we can mount devfs later on.
fs_node_t *root_nodes; // List of file nodes.
int nroot_nodes; // Number of file nodes.
struct dirent dirent;
static uint32_t initrd_read(fs_node_t *node, uint32_t offset, uint32_t size, uint8_t *buffer)
{
initrd_file_header_t header = file_headers[node->inode];
if (offset > header.length)
return 0;
if (offset+size > header.length)
size = header.length-offset;
memcpy(buffer, (uint8_t*) (header.offset+offset), size);
return size;
}
static struct dirent *initrd_readdir(fs_node_t *node, uint32_t index)
{
if (node == initrd_root && index == 0)
{
strcpy(dirent.name, "dev");
dirent.name[3] = 0; // Make sure the string is NULL-terminated.
dirent.ino = 0;
return &dirent;
}
if (index-1 >= nroot_nodes)
return 0;
strcpy(dirent.name, root_nodes[index-1].name);
dirent.name[strlen(root_nodes[index-1].name)] = 0; // Make sure the string is NULL-terminated.
dirent.ino = root_nodes[index-1].inode;
return &dirent;
}
static fs_node_t *initrd_finddir(fs_node_t *node, char *name)
{
if (node == initrd_root &&
!strcmp(name, "dev") )
return initrd_dev;
int i;
for (i = 0; i < nroot_nodes; i++)
if (!strcmp(name, root_nodes[i].name))
return &root_nodes[i];
return 0;
}
fs_node_t *init_initrd(uint32_t location)
{
// Initialise the main and file header pointers and populate the root directory.
initrd_header = (initrd_header_t *)location;
file_headers = (initrd_file_header_t *) (location+sizeof(initrd_header_t));
// Initialise the root directory.
initrd_root = (fs_node_t*)kmalloc(sizeof(fs_node_t));
strcpy(initrd_root->name, "initrd");
initrd_root->mask = initrd_root->uid = initrd_root->gid = initrd_root->inode = initrd_root->length = 0;
initrd_root->flags = FS_DIRECTORY;
initrd_root->read = 0;
initrd_root->write = 0;
initrd_root->open = 0;
initrd_root->close = 0;
initrd_root->readdir = &initrd_readdir;
initrd_root->finddir = &initrd_finddir;
initrd_root->ptr = 0;
initrd_root->impl = 0;
// Initialise the /dev directory (required!)
initrd_dev = (fs_node_t*)kmalloc(sizeof(fs_node_t));
strcpy(initrd_dev->name, "dev");
initrd_dev->mask = initrd_dev->uid = initrd_dev->gid = initrd_dev->inode = initrd_dev->length = 0;
initrd_dev->flags = FS_DIRECTORY;
initrd_dev->read = 0;
initrd_dev->write = 0;
initrd_dev->open = 0;
initrd_dev->close = 0;
initrd_dev->readdir = &initrd_readdir;
initrd_dev->finddir = &initrd_finddir;
initrd_dev->ptr = 0;
initrd_dev->impl = 0;
root_nodes = (fs_node_t*)kmalloc(sizeof(fs_node_t) * initrd_header->nfiles);
nroot_nodes = initrd_header->nfiles;
int i;
for (i = 0; i < initrd_header->nfiles; i++)
{
// Edit the file's header - currently it holds the file offset
// relative to the start of the ramdisk. We want it relative to the start
// of memory.
file_headers[i].offset += location;
// Create a new file node.
strcpy(root_nodes[i].name, &file_headers[i].name);
root_nodes[i].mask = root_nodes[i].uid = root_nodes[i].gid = 0;
root_nodes[i].length = file_headers[i].length;
root_nodes[i].inode = i;
root_nodes[i].flags = FS_FILE;
root_nodes[i].read = &initrd_read;
root_nodes[i].write = 0;
root_nodes[i].readdir = 0;
root_nodes[i].finddir = 0;
root_nodes[i].open = 0;
root_nodes[i].close = 0;
root_nodes[i].impl = 0;
}
return initrd_root;
}

73
kernel/kernel/kernel.c
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@ -1,5 +1,44 @@
#include <stdio.h>
#include <stdint.h>
#include <assert.h>
//#include "fs.c"
//#include "initrd.c"
typedef uint32_t (*read_type_t)(struct fs_node*,uint32_t,uint32_t,uint8_t*);
typedef uint32_t (*write_type_t)(struct fs_node*,uint32_t,uint32_t,uint8_t*);
typedef void (*open_type_t)(struct fs_node*);
typedef void (*close_type_t)(struct fs_node*);
typedef struct dirent * (*readdir_type_t)(struct fs_node*,uint32_t);
typedef struct fs_node * (*finddir_type_t)(struct fs_node*,char *name);
typedef struct fs_node
{
char name[128]; // The filename.
uint32_t mask; // The permissions mask.
uint32_t uid; // The owning user.
uint32_t gid; // The owning group.
uint32_t flags; // Includes the node type. See #defines above.
uint32_t inode; // This is device-specific - provides a way for a filesystem to identify files.
uint32_t length; // Size of the file, in bytes.
uint32_t impl; // An implementation-defined number.
read_type_t read;
write_type_t write;
open_type_t open;
close_type_t close;
readdir_type_t readdir;
finddir_type_t finddir;
struct fs_node *ptr; // Used by mountpoints and symlinks.
} fs_node_t;
struct dirent // One of these is returned by the readdir call, according to POSIX.
{
char name[128]; // Filename.
uint32_t ino; // Inode number. Required by POSIX.
};
extern fs_node_t *fs_root; // The root of the filesystem.
void kernel_main(void) {
printf("Hello from OrionOS!\n");
@ -10,9 +49,37 @@ void kernel_main(void) {
serial_printf("This is string from variable: %s\n", test_string);
printf("Test finished success!\n");
asm volatile("sti");
uint32_t *ptr = (uint32_t*)0xA0000000;
uint32_t do_page_fault = *ptr;
printf("%s", do_page_fault);
// list the contents of /
int i = 0;
struct dirent *node = 0;
while ( (node = readdir_fs(fs_root, i)) != 0)
{
serial_printf("Found file %s", node->name);
fs_node_t *fsnode = finddir_fs(fs_root, node->name);
if ((fsnode->flags&0x7) == 0x02)//FS_DIRECTORY)
serial_printf("\n\t(directory)\n");
else
{
printf("\n\t contents: \"");
char buf[256];
uint32_t sz = read_fs(fsnode, 0, 256, buf);
uint32_t j;
for (j = 0; j < sz; j++)
serial_printf("%c", buf[j]);
serial_printf("\"\n");
}
i++;
}
//printf("%x\n", 0x0);
//printf("%x\n", a);
printf("%x");
/*for (int i = 0; i < 1000; i++) {
printf("A: %c\n", i);
}*/
close_fs(fs_root);
for(;;) {
asm("hlt");
}

365
kernel/kernel/kheap.c Normal file
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@ -0,0 +1,365 @@
#include "ordered_map.c"
extern uint32_t page_directory[1024];
#define KHEAP_START 0xC0000000
#define KHEAP_INITIAL_SIZE 0x100000
#define HEAP_INDEX_SIZE 0x20000
#define HEAP_MAGIC 0x123890AB
#define HEAP_MIN_SIZE 0x70000
typedef struct
{
uint32_t magic; // Magic number, used for error checking and identification.
uint8_t is_hole; // 1 if this is a hole. 0 if this is a block.
uint32_t size; // size of the block, including the end footer.
} header_t;
typedef struct
{
uint32_t magic; // Magic number, same as in header_t.
header_t *header; // Pointer to the block header.
} footer_t;
typedef struct
{
ordered_array_t index;
uint32_t start_address; // The start of our allocated space.
uint32_t end_address; // The end of our allocated space. May be expanded up to max_address.
uint32_t max_address; // The maximum address the heap can be expanded to.
uint8_t supervisor; // Should extra pages requested by us be mapped as supervisor-only?
uint8_t readonly; // Should extra pages requested by us be mapped as read-only?
} heap_t;
heap_t *kheap;
static int32_t find_smallest_hole(uint32_t size, uint8_t page_align, heap_t *heap)
{
// Find the smallest hole that will fit.
uint32_t iterator = 0;
while (iterator < heap->index.size)
{
header_t *header = (header_t *)lookup_ordered_array(iterator, &heap->index);
// If the user has requested the memory be page-aligned
if (page_align > 0)
{
// Page-align the starting point of this header.
uint32_t location = (uint32_t)header;
int32_t offset = 0;
if (((location+sizeof(header_t)) & 0xFFFFF000) != 0)
offset = 0x1000 /* page size */ - (location+sizeof(header_t))%0x1000;
int32_t hole_size = (int32_t)header->size - offset;
// Can we fit now?
if (hole_size >= (int32_t)size)
break;
}
else if (header->size >= size)
break;
iterator++;
}
// Why did the loop exit?
if (iterator == heap->index.size)
return -1; // We got to the end and didn't find anything.
else
return iterator;
}
static int8_t header_t_less_than(void*a, void *b)
{
return (((header_t*)a)->size < ((header_t*)b)->size)?1:0;
}
heap_t *create_heap(uint32_t start, uint32_t end_addr, uint32_t max, uint8_t supervisor, uint8_t readonly)
{
heap_t *heap = (heap_t*)kmalloc(sizeof(heap_t));
// All our assumptions are made on startAddress and endAddress being page-aligned.
assert(start%0x1000 == 0);
assert(end_addr%0x1000 == 0);
// Initialise the index.
heap->index = place_ordered_array( (void*)start, HEAP_INDEX_SIZE, &header_t_less_than);
// Shift the start address forward to resemble where we can start putting data.
start += sizeof(type_t)*HEAP_INDEX_SIZE;
// Make sure the start address is page-aligned.
if ((start & 0xFFFFF000) != 0)
{
start &= 0xFFFFF000;
start += 0x1000;
}
// Write the start, end and max addresses into the heap structure.
heap->start_address = start;
heap->end_address = end_addr;
heap->max_address = max;
heap->supervisor = supervisor;
heap->readonly = readonly;
// We start off with one large hole in the index.
header_t *hole = (header_t *)start;
hole->size = end_addr-start;
hole->magic = HEAP_MAGIC;
hole->is_hole = 1;
insert_ordered_array((void*)hole, &heap->index);
return heap;
}
static void expand(uint32_t new_size, heap_t *heap)
{
// Sanity check.
assert(new_size > heap->end_address - heap->start_address);
// Get the nearest following page boundary.
if ((new_size&0xFFFFF000) != 0)
{
new_size &= 0xFFFFF000;
new_size += 0x1000;
}
// Make sure we are not overreaching ourselves.
assert(heap->start_address+new_size <= heap->max_address);
// This should always be on a page boundary.
uint32_t old_size = heap->end_address-heap->start_address;
uint32_t i = old_size;
while (i < new_size)
{
alloc_frame( get_page(heap->start_address+i, 1, /*kernel*/page_directory),
(heap->supervisor)?1:0, (heap->readonly)?0:1);
i += 0x1000 /* page size */;
}
heap->end_address = heap->start_address+new_size;
}
static uint32_t contract(uint32_t new_size, heap_t *heap)
{
// Sanity check.
assert(new_size < heap->end_address-heap->start_address);
// Get the nearest following page boundary.
if (new_size&0x1000)
{
new_size &= 0x1000;
new_size += 0x1000;
}
// Don't contract too far!
if (new_size < HEAP_MIN_SIZE)
new_size = HEAP_MIN_SIZE;
uint32_t old_size = heap->end_address-heap->start_address;
uint32_t i = old_size - 0x1000;
while (new_size < i)
{
free_frame(get_page(heap->start_address+i, 0, /*kernel*/page_directory));
i -= 0x1000;
}
heap->end_address = heap->start_address + new_size;
return new_size;
}
void *alloc(uint32_t size, uint8_t page_align, heap_t *heap)
{
// Make sure we take the size of header/footer into account.
uint32_t new_size = size + sizeof(header_t) + sizeof(footer_t);
// Find the smallest hole that will fit.
int32_t iterator = find_smallest_hole(new_size, page_align, heap);
if (iterator == -1) // If we didn't find a suitable hole
{
// Save some previous data.
uint32_t old_length = heap->end_address - heap->start_address;
uint32_t old_end_address = heap->end_address;
// We need to allocate some more space.
expand(old_length+new_size, heap);
uint32_t new_length = heap->end_address-heap->start_address;
// Find the endmost header. (Not endmost in size, but in location).
iterator = 0;
// Vars to hold the index of, and value of, the endmost header found so far.
uint32_t idx = -1; uint32_t value = 0x0;
while (iterator < heap->index.size)
{
uint32_t tmp = (uint32_t)lookup_ordered_array(iterator, &heap->index);
if (tmp > value)
{
value = tmp;
idx = iterator;
}
iterator++;
}
// If we didn't find ANY headers, we need to add one.
if (idx == -1)
{
header_t *header = (header_t *)old_end_address;
header->magic = HEAP_MAGIC;
header->size = new_length - old_length;
header->is_hole = 1;
footer_t *footer = (footer_t *) (old_end_address + header->size - sizeof(footer_t));
footer->magic = HEAP_MAGIC;
footer->header = header;
insert_ordered_array((void*)header, &heap->index);
}
else
{
// The last header needs adjusting.
header_t *header = lookup_ordered_array(idx, &heap->index);
header->size += new_length - old_length;
// Rewrite the footer.
footer_t *footer = (footer_t *) ( (uint32_t)header + header->size - sizeof(footer_t) );
footer->header = header;
footer->magic = HEAP_MAGIC;
}
// We now have enough space. Recurse, and call the function again.
return alloc(size, page_align, heap);
}
header_t *orig_hole_header = (header_t *)lookup_ordered_array(iterator, &heap->index);
uint32_t orig_hole_pos = (uint32_t)orig_hole_header;
uint32_t orig_hole_size = orig_hole_header->size;
// Here we work out if we should split the hole we found into two parts.
// Is the original hole size - requested hole size less than the overhead for adding a new hole?
if (orig_hole_size-new_size < sizeof(header_t)+sizeof(footer_t))
{
// Then just increase the requested size to the size of the hole we found.
size += orig_hole_size-new_size;
new_size = orig_hole_size;
}
// If we need to page-align the data, do it now and make a new hole in front of our block.
if (page_align && orig_hole_pos & 0xFFFFF000)
{
uint32_t new_location = orig_hole_pos + 0x1000 /* page size */ - (orig_hole_pos&0xFFF) - sizeof(header_t);
header_t *hole_header = (header_t *)orig_hole_pos;
hole_header->size = 0x1000 /* page size */ - (orig_hole_pos&0xFFF) - sizeof(header_t);
hole_header->magic = HEAP_MAGIC;
hole_header->is_hole = 1;
footer_t *hole_footer = (footer_t *) ( (uint32_t)new_location - sizeof(footer_t) );
hole_footer->magic = HEAP_MAGIC;
hole_footer->header = hole_header;
orig_hole_pos = new_location;
orig_hole_size = orig_hole_size - hole_header->size;
}
else
{
// Else we don't need this hole any more, delete it from the index.
remove_ordered_array(iterator, &heap->index);
}
// Overwrite the original header...
header_t *block_header = (header_t *)orig_hole_pos;
block_header->magic = HEAP_MAGIC;
block_header->is_hole = 0;
block_header->size = new_size;
// ...And the footer
footer_t *block_footer = (footer_t *) (orig_hole_pos + sizeof(header_t) + size);
block_footer->magic = HEAP_MAGIC;
block_footer->header = block_header;
// We may need to write a new hole after the allocated block.
// We do this only if the new hole would have positive size...
if (orig_hole_size - new_size > 0)
{
header_t *hole_header = (header_t *) (orig_hole_pos + sizeof(header_t) + size + sizeof(footer_t));
hole_header->magic = HEAP_MAGIC;
hole_header->is_hole = 1;
hole_header->size = orig_hole_size - new_size;
footer_t *hole_footer = (footer_t *) ( (uint32_t)hole_header + orig_hole_size - new_size - sizeof(footer_t) );
if ((uint32_t)hole_footer < heap->end_address)
{
hole_footer->magic = HEAP_MAGIC;
hole_footer->header = hole_header;
}
// Put the new hole in the index;
insert_ordered_array((void*)hole_header, &heap->index);
}
return (void *) ( (uint32_t)block_header+sizeof(header_t) );
}
void free(void *p, heap_t *heap)
{
// Exit gracefully for null pointers.
if (p == 0)
return;
// Get the header and footer associated with this pointer.
header_t *header = (header_t*) ( (uint32_t)p - sizeof(header_t) );
footer_t *footer = (footer_t*) ( (uint32_t)header + header->size - sizeof(footer_t) );
// Sanity checks.
assert(header->magic == HEAP_MAGIC);
assert(footer->magic == HEAP_MAGIC);
// Make us a hole.
header->is_hole = 1;
// Do we want to add this header into the 'free holes' index?
char do_add = 1;
// Unify left
// If the thing immediately to the left of us is a footer...
footer_t *test_footer = (footer_t*) ( (uint32_t)header - sizeof(footer_t) );
if (test_footer->magic == HEAP_MAGIC &&
test_footer->header->is_hole == 1)
{
uint32_t cache_size = header->size; // Cache our current size.
header = test_footer->header; // Rewrite our header with the new one.
footer->header = header; // Rewrite our footer to point to the new header.
header->size += cache_size; // Change the size.
do_add = 0; // Since this header is already in the index, we don't want to add it again.
}
// Unify right
// If the thing immediately to the right of us is a header...
header_t *test_header = (header_t*) ( (uint32_t)footer + sizeof(footer_t) );
if (test_header->magic == HEAP_MAGIC &&
test_header->is_hole)
{
header->size += test_header->size; // Increase our size.
test_footer = (footer_t*) ( (uint32_t)test_header + // Rewrite it's footer to point to our header.
test_header->size - sizeof(footer_t) );
footer = test_footer;
// Find and remove this header from the index.
uint32_t iterator = 0;
while ( (iterator < heap->index.size) &&
(lookup_ordered_array(iterator, &heap->index) != (void*)test_header) )
iterator++;
// Make sure we actually found the item.
assert(iterator < heap->index.size);
// Remove it.
remove_ordered_array(iterator, &heap->index);
}
// If the footer location is the end address, we can contract.
if ( (uint32_t)footer+sizeof(footer_t) == heap->end_address)
{
uint32_t old_length = heap->end_address-heap->start_address;
uint32_t new_length = contract( (uint32_t)header - heap->start_address, heap);
// Check how big we will be after resizing.
if (header->size - (old_length-new_length) > 0)
{
// We will still exist, so resize us.
header->size -= old_length-new_length;
footer = (footer_t*) ( (uint32_t)header + header->size - sizeof(footer_t) );
footer->magic = HEAP_MAGIC;
footer->header = header;
}
else
{
// We will no longer exist :(. Remove us from the index.
uint32_t iterator = 0;
while ( (iterator < heap->index.size) &&
(lookup_ordered_array(iterator, &heap->index) != (void*)test_header) )
iterator++;
// If we didn't find ourselves, we have nothing to remove.
if (iterator < heap->index.size)
remove_ordered_array(iterator, &heap->index);
}
}
if (do_add == 1)
insert_ordered_array((void*) header, &heap->index);
}

41
kernel/kernel/multiboot.h Normal file
View File

@ -0,0 +1,41 @@
#define MULTIBOOT_FLAG_MEM 0x001
#define MULTIBOOT_FLAG_DEVICE 0x002
#define MULTIBOOT_FLAG_CMDLINE 0x004
#define MULTIBOOT_FLAG_MODS 0x008
#define MULTIBOOT_FLAG_AOUT 0x010
#define MULTIBOOT_FLAG_ELF 0x020
#define MULTIBOOT_FLAG_MMAP 0x040
#define MULTIBOOT_FLAG_CONFIG 0x080
#define MULTIBOOT_FLAG_LOADER 0x100
#define MULTIBOOT_FLAG_APM 0x200
#define MULTIBOOT_FLAG_VBE 0x400
struct multiboot
{
uint32_t flags;
uint32_t mem_lower;
uint32_t mem_upper;
uint32_t boot_device;
uint32_t cmdline;
uint32_t mods_count;
uint32_t mods_addr;
uint32_t num;
uint32_t size;
uint32_t addr;
uint32_t shndx;
uint32_t mmap_length;
uint32_t mmap_addr;
uint32_t drives_length;
uint32_t drives_addr;
uint32_t config_table;
uint32_t boot_loader_name;
uint32_t apm_table;
uint32_t vbe_control_info;
uint32_t vbe_mode_info;
uint32_t vbe_mode;
uint32_t vbe_interface_seg;
uint32_t vbe_interface_off;
uint32_t vbe_interface_len;
} __attribute__((packed));
typedef struct multiboot_header multiboot_header_t;

84
kernel/kernel/ordered_map.c Normal file
View File

@ -0,0 +1,84 @@
#include <string.h>
typedef void* type_t;
typedef int8_t (*lessthan_predicate_t)(type_t,type_t);
typedef struct
{
type_t *array;
uint32_t size;
uint32_t max_size;
lessthan_predicate_t less_than;
} ordered_array_t;
standard_lessthan_predicate(type_t a, type_t b)
{
return (a<b)?1:0;
}
ordered_array_t create_ordered_array(uint32_t max_size, lessthan_predicate_t less_than)
{
ordered_array_t to_ret;
to_ret.array = (void*)kmalloc(max_size*sizeof(type_t));
memset(to_ret.array, 0, max_size*sizeof(type_t));
to_ret.size = 0;
to_ret.max_size = max_size;
to_ret.less_than = less_than;
return to_ret;
}
ordered_array_t place_ordered_array(void *addr, uint32_t max_size, lessthan_predicate_t less_than)
{
ordered_array_t to_ret;
to_ret.array = (type_t*)addr;
memset(to_ret.array, 0, max_size*sizeof(type_t));
to_ret.size = 0;
to_ret.max_size = max_size;
to_ret.less_than = less_than;
return to_ret;
}
void destroy_ordered_array(ordered_array_t *array)
{
// kfree(array->array);
}
void insert_ordered_array(type_t item, ordered_array_t *array)
{
assert(array->less_than);
uint32_t iterator = 0;
while (iterator < array->size && array->less_than(array->array[iterator], item))
iterator++;
if (iterator == array->size) // just add at the end of the array.
array->array[array->size++] = item;
else
{
type_t tmp = array->array[iterator];
array->array[iterator] = item;
while (iterator < array->size)
{
iterator++;
type_t tmp2 = array->array[iterator];
array->array[iterator] = tmp;
tmp = tmp2;
}
array->size++;
}
}
type_t lookup_ordered_array(uint32_t i, ordered_array_t *array)
{
assert(i < array->size);
return array->array[i];
}
void remove_ordered_array(uint32_t i, ordered_array_t *array)
{
while (i < array->size)
{
array->array[i] = array->array[i+1];
i++;
}
array->size--;
}

179
kernel/kernel/paging.h
View File

@ -1,4 +1,10 @@
#include <stdio.h>
#include <string.h>
//#include "kheap.c"
uint32_t placement_address; //FIXME
uint32_t *frames;
uint32_t nframes;
/*
Handler for page faults.
@ -26,14 +32,184 @@ void page_fault(registers_t regs){
printf("PAGE FAULT\n");
}
uint32_t kmalloc(uint32_t sz) // FIXME
{
uint32_t tmp = placement_address;
placement_address += sz;
return tmp;
}
typedef struct page
{
uint32_t present : 1; // Page present in memory
uint32_t rw : 1; // Read-only if clear, readwrite if set
uint32_t user : 1; // Supervisor level only if clear
uint32_t accessed : 1; // Has the page been accessed since last refresh?
uint32_t dirty : 1; // Has the page been written to since last refresh?
uint32_t unused : 7; // Amalgamation of unused and reserved bits
uint32_t frame : 20; // Frame address (shifted right 12 bits)
} page_t;
typedef struct page_table
{
page_t pages[1024];
} page_table_t;
typedef struct page_directory
{
/**
Array of pointers to pagetables.
**/
page_table_t *tables[1024];
/**
Array of pointers to the pagetables above, but gives their *physical*
location, for loading into the CR3 register.
**/
uint32_t tablesPhysical[1024];
/**
The physical address of tablesPhysical. This comes into play
when we get our kernel heap allocated and the directory
may be in a different location in virtual memory.
**/
uint32_t physicalAddr;
} page_directory_t;
uint32_t page_directory[1024] __attribute__((aligned(4096)));
uint32_t first_page_table[1024] __attribute__((aligned(4096)));
extern void loadPageDirectory(unsigned int*);
extern void enable_paging();
//extern heap_t *kheap;
uint32_t kmalloc_ap(uint32_t sz, uint32_t *phys)
{
if (placement_address & 0xFFFFF000) // If the address is not already page-aligned
{
// Align it.
placement_address &= 0xFFFFF000;
placement_address += 0x1000;
}
if (phys)
{
*phys = placement_address;
}
uint32_t tmp = placement_address;
placement_address += sz;
return tmp;
}
// Macros used in the bitset algorithms.
#define INDEX_FROM_BIT(a) (a/(8*4))
#define OFFSET_FROM_BIT(a) (a%(8*4))
// Static function to set a bit in the frames bitset
static void set_frame(uint32_t frame_addr)
{
uint32_t frame = frame_addr/0x1000;
uint32_t idx = INDEX_FROM_BIT(frame);
uint32_t off = OFFSET_FROM_BIT(frame);
frames[idx] |= (0x1 << off);
}
// Static function to clear a bit in the frames bitset
static void clear_frame(uint32_t frame_addr)
{
uint32_t frame = frame_addr/0x1000;
uint32_t idx = INDEX_FROM_BIT(frame);
uint32_t off = OFFSET_FROM_BIT(frame);
frames[idx] &= ~(0x1 << off);
}
// Static function to find the first free frame.
static uint32_t first_frame()
{
uint32_t i, j;
for (i = 0; i < INDEX_FROM_BIT(nframes); i++)
{
if (frames[i] != 0xFFFFFFFF) // nothing free, exit early.
{
// at least one bit is free here.
for (j = 0; j < 32; j++)
{
uint32_t toTest = 0x1 << j;
if ( !(frames[i]&toTest) )
{
return i*4*8+j;
}
}
}
}
}
void alloc_frame(page_t *page, int is_kernel, int is_writeable)
{
if (page->frame != 0)
{
return; // Frame was already allocated, return straight away.
}
else
{
uint32_t idx = first_frame(); // idx is now the index of the first free frame.
if (idx == (uint32_t)-1)
{
// PANIC is just a macro that prints a message to the screen then hits an infinite loop.
printf("No free frames!");
}
set_frame(idx*0x1000); // this frame is now ours!
page->present = 1; // Mark it as present.
page->rw = (is_writeable)?1:0; // Should the page be writeable?
page->user = (is_kernel)?0:1; // Should the page be user-mode?
page->frame = idx;
}
}
// Function to deallocate a frame.
void free_frame(page_t *page)
{
uint32_t frame;
if (!(frame=page->frame))
{
return; // The given page didn't actually have an allocated frame!
}
else
{
clear_frame(frame); // Frame is now free again.
page->frame = 0x0; // Page now doesn't have a frame.
}
}
page_t *get_page(uint32_t address, int make, page_directory_t *dir)
{
// Turn the address into an index.
address /= 0x1000;
// Find the page table containing this address.
uint32_t table_idx = address / 1024;
if (dir->tables[table_idx]) // If this table is already assigned
{
return &dir->tables[table_idx]->pages[address%1024];
}
else if(make)
{
uint32_t tmp;
dir->tables[table_idx] = (page_table_t*)kmalloc_ap(sizeof(page_table_t), &tmp);
memset(dir->tables[table_idx], 0, 0x1000);
dir->tablesPhysical[table_idx] = tmp | 0x7; // PRESENT, RW, US.
return &dir->tables[table_idx]->pages[address%1024];
}
else
{
return 0;
}
}
void init_paging() {
// The size of physical memory. For the moment we
// assume it is 16MB big.
uint32_t mem_end_page = 0x1000000;
nframes = mem_end_page / 0x1000;
frames = (uint32_t*)kmalloc(INDEX_FROM_BIT(nframes));
memset(frames, 0, INDEX_FROM_BIT(nframes));
//set each entry to not present
int i;
for(i = 0; i < 1024; i++)
@ -60,4 +236,7 @@ void init_paging() {
loadPageDirectory(page_directory);
enable_paging();
// Initialise the kernel heap.
//kheap = create_heap(KHEAP_START, KHEAP_START+KHEAP_INITIAL_SIZE, 0xCFFFF000, 0, 0);
}

10
libc/include/assert.h Normal file
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@ -0,0 +1,10 @@
#ifndef _ASSERT_H
#define _ASSERT_H 1
#ifdef NDEBUG
#define assert(condition) ((void)0)
#else
#define assert(condition) /*implementation defined*/
#endif
#endif

12
libc/stdio/printf.c
View File

@ -61,6 +61,18 @@ int printf(const char* restrict format, ...) {
if (!print(str, len))
return -1;
written += len;
} else if (*format == 'x') {
format++;
int c = va_arg(parameters, int);
c = c == 10 ? 17 : c;
if (!maxrem) {
// TODO: Set errno to EOVERFLOW.
return -1;
}
if (!print("0x", &c))
return -1;
written++;
} else {
format = format_begun_at;
size_t len = strlen(format);