Mark
95 lines
2.3 KiB
C
95 lines
2.3 KiB
C
#include "sys/string.h"
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#include "sys/random.h"
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#include "sys/panic.h"
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#include "sys/errno.h"
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#include "sys/attr.h"
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#include "sys/blk.h"
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#include "sys/dev.h"
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#define DEV_ZERO 0
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#define DEV_NULL 1
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#define DEV_URANDOM 2
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static ssize_t pseudo_write(struct blkdev *dev, const void *buf, size_t pos, size_t lim);
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static ssize_t pseudo_read(struct blkdev *dev, void *buf, size_t pos, size_t lim);
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static void urandom_fill(void *buf, size_t lim) {
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uint64_t val;
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size_t i = 0;
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while (i < lim) {
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val = random_single();
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memcpy(buf + i, &val, MIN(lim - i, 8));
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i += 8;
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}
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}
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static struct blkdev _dev_null = {
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.dev_data = (void *) DEV_NULL,
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.write = pseudo_write,
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.read = pseudo_read
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};
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static struct dev_entry _ent_null = {
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.dev = &_dev_null,
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.dev_class = DEV_CLASS_BLOCK,
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.dev_subclass = DEV_BLOCK_PSEUDO,
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.dev_name = "null"
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};
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static struct blkdev _dev_zero = {
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.dev_data = (void *) DEV_ZERO,
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.write = pseudo_write,
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.read = pseudo_read
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};
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static struct dev_entry _ent_zero = {
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.dev = &_dev_zero,
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.dev_class = DEV_CLASS_BLOCK,
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.dev_subclass = DEV_BLOCK_PSEUDO,
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.dev_name = "zero"
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};
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static struct blkdev _dev_urandom = {
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.dev_data = (void *) DEV_URANDOM,
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.write = pseudo_write,
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.read = pseudo_read
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};
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static struct dev_entry _ent_urandom = {
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.dev = &_dev_urandom,
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.dev_class = DEV_CLASS_BLOCK,
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.dev_subclass = DEV_BLOCK_PSEUDO,
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.dev_name = "urandom"
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};
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static ssize_t pseudo_write(struct blkdev *dev, const void *buf, size_t pos, size_t lim) {
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switch ((uint64_t) dev->dev_data) {
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case DEV_NULL:
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case DEV_ZERO:
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return lim;
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case DEV_URANDOM:
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return -EINVAL;
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default:
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panic("Unexpected dev id: %p\n", dev->dev_data);
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}
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}
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static ssize_t pseudo_read(struct blkdev *dev, void *buf, size_t pos, size_t lim) {
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switch ((uint64_t) dev->dev_data) {
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case DEV_ZERO:
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memset(buf, 0, lim);
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return lim;
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case DEV_NULL:
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return 0;
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case DEV_URANDOM:
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urandom_fill(buf, lim);
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return lim;
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default:
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panic("Unexpected dev id: %p\n", dev->dev_data);
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}
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}
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static __init void pseudo_init(void) {
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dev_entry_add(&_ent_null);
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dev_entry_add(&_ent_zero);
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dev_entry_add(&_ent_urandom);
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}
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