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#include <assert.h>
#include <errno.h>
#include <fcntl.h>
#include <fs/shm.h>
#include <fs/vfs.h>
#include <hashmap/hashmap.h>
#include <mmu.h>
#include <sched/scheduler.h>
#include <stddef.h>
HashMap *shared_memory_objects;
void shm_init(void) {
shared_memory_objects = hashmap_create(10);
}
int shm_write(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
vfs_vm_object_t *p = fd->inode->internal_object;
if (offset > p->size) {
return -EFBIG;
}
if (offset + len > p->size) {
len = p->size - offset;
}
memcpy((void *)((uintptr_t)((uintptr_t)p->virtual_object + offset)), buffer,
len);
return len;
}
int shm_read(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
vfs_vm_object_t *p = fd->inode->internal_object;
if (offset > p->size) {
return -EFBIG;
}
if (offset + len > p->size) {
len = p->size - offset;
}
memcpy((void *)buffer,
(void *)((uintptr_t)((uintptr_t)p->virtual_object + offset)), len);
return len;
}
vfs_vm_object_t *shm_get_vm_object(u64 length, u64 offset, vfs_fd_t *fd) {
(void)length;
(void)offset;
vfs_vm_object_t *p = fd->inode->internal_object;
return p;
}
int shm_ftruncate(vfs_fd_t *fd, size_t length) {
vfs_vm_object_t *p = fd->inode->internal_object;
if (p->real_pointer) {
u8 *mem_region = p->real_pointer;
mmu_free_address_range(mem_region, align_page(p->size), NULL);
}
p->real_pointer = mmu_find_unallocated_virtual_range(NULL, length);
if (!mmu_allocate_region(p->real_pointer, length, MMU_FLAG_RW, NULL)) {
return -ENOMEM;
}
p->size = length;
p->virtual_object = p->real_pointer;
int n = (uintptr_t)align_page((void *)(u32)length) / 0x1000;
p->object = krealloc(p->object, sizeof(void *) * n);
for (int i = 0; i < n; i++) {
p->object[i] =
(void *)(get_page(p->virtual_object + (i * 0x1000), NULL, 0, 0)->frame *
0x1000);
}
return 0;
}
void shm_close(vfs_fd_t *fd) {
vfs_vm_object_t *internal_object = fd->inode->internal_object;
assert(internal_object->num_of_references > 0);
internal_object->num_of_references--;
}
int shm_open(const char *name, int oflag, mode_t mode) {
// Try to find or create a new shared memory object.
vfs_vm_object_t *internal_object =
hashmap_get_entry(shared_memory_objects, name);
if (!internal_object) {
if (!(oflag & O_CREAT)) {
return -ENOENT;
}
internal_object = kcalloc(1, sizeof(vfs_vm_object_t));
hashmap_add_entry(shared_memory_objects, name, internal_object, NULL, 0);
}
internal_object->num_of_references++;
vfs_inode_t *inode = vfs_create_inode(
0 /*inode_num*/, 0 /*type*/, NULL, NULL, 1 /*is_open*/, 0,
internal_object, 0 /*file_size*/, NULL /*open*/, NULL /*create_file*/,
shm_read, shm_write, shm_close, NULL /*create_directory*/,
shm_get_vm_object, shm_ftruncate, NULL /*stat*/, NULL /*send_signal*/,
NULL /*connect*/);
vfs_fd_t *fd_ptr;
int fd = vfs_create_fd(oflag, mode, 0 /*is_tty*/, inode, &fd_ptr);
if (-1 == fd) {
kfree(inode);
return -EMFILE;
}
return fd;
}
int shm_unlink(const char *name) {
vfs_vm_object_t *p = hashmap_get_entry(shared_memory_objects, name);
if (!p) {
return -ENOENT;
}
if (0 != p->num_of_references) {
p->num_of_references--;
}
if (0 == p->num_of_references && p->real_pointer) {
u8 *mem_region = p->real_pointer;
mmu_free_address_range(mem_region, align_page(p->size), NULL);
p->real_pointer = NULL;
p->size = 0;
}
assert(hashmap_delete_entry(shared_memory_objects, name));
return 0;
}
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