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#include <kernel/arch/i386/ata.h>
#include <kernel/mem/virt.h>
#include <kernel/panic.h>
#include <kernel/proc.h>
#include <kernel/util.h>
#include <kernel/arch/i386/driver/fsroot.h>
#include <shared/mem.h>
#include <stdbool.h>
enum {
HANDLE_ROOT,
HANDLE_VGA,
HANDLE_ATA_ROOT,
HANDLE_ATA,
_SKIP = HANDLE_ATA + 4,
};
static bool exacteq(struct vfs_request *req, const char *str) {
size_t len = strlen(str);
assert(req->input.kern);
return req->input.len == len && !memcmp(req->input.buf_kern, str, len);
}
/* truncates the length */
static void req_preprocess(struct vfs_request *req, size_t max_len) {
if (req->offset < 0) {
// TODO negative offsets
req->offset = 0;
}
if (req->offset >= capped_cast32(max_len)) {
req->input.len = 0;
req->output.len = 0;
req->offset = max_len;
return;
}
req->input.len = min(req->input.len, max_len - req->offset);
req->output.len = min(req->output.len, max_len - req->offset);
assert(req->input.len + req->offset <= max_len);
assert(req->input.len + req->offset <= max_len);
}
static int handle(struct vfs_request *req) {
assert(req->caller);
switch (req->type) {
case VFSOP_OPEN:
if (exacteq(req, "/")) return HANDLE_ROOT;
if (exacteq(req, "/vga")) return HANDLE_VGA;
if (exacteq(req, "/ata/")) return HANDLE_ATA_ROOT;
if (exacteq(req, "/ata/0"))
return ata_available(0) ? HANDLE_ATA+0 : -1;
if (exacteq(req, "/ata/1"))
return ata_available(1) ? HANDLE_ATA+1 : -1;
if (exacteq(req, "/ata/2"))
return ata_available(2) ? HANDLE_ATA+2 : -1;
if (exacteq(req, "/ata/3"))
return ata_available(3) ? HANDLE_ATA+3 : -1;
return -1;
case VFSOP_READ:
switch (req->id) {
case HANDLE_ROOT: {
// TODO document directory read format
const char src[] =
"vga\0"
"com1\0"
"ps2\0"
"ata/";
int len = min((size_t) req->output.len, sizeof(src));
virt_cpy_to(req->caller->pages, req->output.buf, src, len);
return len;
}
case HANDLE_VGA: {
char *vga = (void*)0xB8000;
req_preprocess(req, 80*25*2);
virt_cpy_to(req->caller->pages, req->output.buf,
vga + req->offset, req->output.len);
return req->output.len;
}
case HANDLE_ATA_ROOT: {
// TODO offset
char list[8] = {};
size_t len = 0;
for (int i = 0; i < 4; i++) {
if (ata_available(i)) {
list[len] = '0' + i;
len += 2;
}
}
len = min((size_t) req->output.len, len);
virt_cpy_to(req->caller->pages, req->output.buf, list, len);
return len;
}
case HANDLE_ATA: case HANDLE_ATA+1:
case HANDLE_ATA+2: case HANDLE_ATA+3: {
if (req->offset < 0) return 0;
char buf[512];
uint32_t sector = req->offset / 512;
size_t len = min(req->output.len, 512 - ((size_t)req->offset & 511));
ata_read(req->id - HANDLE_ATA, sector, buf);
virt_cpy_to(req->caller->pages, req->output.buf, buf, len);
return len;
}
default: panic_invalid_state();
}
case VFSOP_WRITE:
switch (req->id) {
case HANDLE_VGA: {
void *vga = (void*)0xB8000;
req_preprocess(req, 80*25*2);
virt_cpy_from(req->caller->pages, vga + req->offset,
req->input.buf, req->input.len);
return req->input.len;
}
default: return -1;
}
case VFSOP_CLOSE:
return 0;
default: panic_invalid_state();
}
}
static void accept(struct vfs_request *req) {
if (req->caller) {
vfsreq_finish(req, handle(req));
} else {
vfsreq_finish(req, -1);
}
}
static bool is_ready(struct vfs_backend *self) {
return true;
}
static struct vfs_backend backend = BACKEND_KERN(is_ready, accept);
void vfs_root_init(void) { vfs_mount_root_register("", &backend); }
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