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#include "fs/fs.h"
#include "kernel/riscv.h"
#include "drivers/uart.h"
#include "kernel/spinlock.h"
#include "kernel/proc.h"
#include "fs/fat32.h"
#include "lib/string.h"
static Inode *global_root_inode = nullptr;
static const char *skipelem(const char *path, char *name)
{
const char *s;
int len;
while (*path == '/')
path++;
if (*path == 0)
return nullptr;
s = path;
while (*path != '/' && *path != 0)
path++;
len = path - s;
if (len >= 128)
len = 127;
memmove(name, s, len);
name[len] = 0;
while (*path == '/')
path++;
return path;
}
void Inode::getattr(struct kstat *st)
{
st->dev = dev;
st->ino = inum;
st->type = type;
st->nlink = nlink;
st->size = size;
st->uid = 0;
st->gid = 0;
st->mode = 0;
}
namespace VFS
{
void init()
{
Drivers::uart_puts("[VFS] Inode subsystem initialized.\n");
}
void iput(Inode *ip)
{
if (ip == nullptr)
return;
ip->lock.acquire();
if(ip->ref_cnt < 1)
{
Drivers::uart_puts("panic: iput ref\n");
while (1)
;
}
ip->ref_cnt--;
int ref = ip->ref_cnt;
ip->lock.release();
if (ref == 0)
{
delete ip;
}
}
Inode* idup(Inode *ip)
{
if (ip == nullptr)
return nullptr;
ip->lock.acquire();
ip->ref_cnt++;
ip->lock.release();
return ip;
}
void ilock(Inode *ip)
{
if (ip == 0 || ip->ref_cnt < 1)
{
Drivers::uart_puts("panic: ilock\n");
while (1)
;
}
ip->lock.acquire();
}
void iunlock(Inode *ip)
{
if (ip == 0 || !ip->lock.holding() || ip->ref_cnt < 1)
{
Drivers::uart_puts("panic: iunlock\n");
while (1)
;
}
ip->lock.release();
}
static void iunlockput(Inode *ip)
{
iunlock(ip);
iput(ip);
}
void mount_root(Inode *root)
{
if (global_root_inode)
{
Drivers::uart_puts("VFS: Root already mounted!\n");
return;
}
global_root_inode = root;
Drivers::uart_puts("[VFS] Root filesystem mounted.\n");
}
Inode *get_root()
{
if (global_root_inode == nullptr)
{
Drivers::uart_puts("[VFS] Lazy init: Mounting FAT32...\n");
fat32_fs.init();
mount_root(fat32_fs.root());
}
if (!global_root_inode)
return nullptr;
return idup(global_root_inode);
}
Inode *namei(const char *path)
{
char name[128];
Inode *ip, *next;
struct Proc *p = myproc();
if (*path == '/')
{
ip = get_root();
}
else
{
if (p->cwd == nullptr)
{
ip = get_root();
}
else
{
ip = idup(p->cwd);
}
}
if (ip == nullptr)
return nullptr;
while ((path = skipelem(path, name)) != nullptr)
{
ilock(ip);
if (ip->type != T_DIR)
{
iunlockput(ip);
return nullptr;
}
next = ip->lookup(name);
iunlockput(ip);
ip = next;
if (ip == nullptr)
return nullptr;
}
return ip;
}
} // namespace VFS
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