/*
* Removes an entry from a directory.
*/
PUBLIC int dir_remove(struct inode *dinode, const char *filename)
{
struct buffer *buf; /* Block buffer. */
struct d_dirent *d; /* Directory entry. */
struct inode *file; /* File inode. */
d = dirent_search(dinode, filename, &buf, 0);
/* Not found. */
if (d == NULL)
return (-ENOENT);
/* Cannot remove '.' */
if (d->d_ino == dinode->num)
{
brelse(buf);
return (-EBUSY);
}
file = inode_get(dinode->dev, d->d_ino);
/* Failed to get file's inode. */
if (file == NULL)
{
brelse(buf);
return (-ENOENT);
}
/* Unlinking directory. */
if (S_ISDIR(file->mode))
{
/* Not allowed. */
if (!IS_SUPERUSER(curr_proc))
{
inode_put(file);
brelse(buf);
return (-EPERM);
}
/* Directory not empty. */
if (dinode->size)
{
inode_put(file);
brelse(buf);
return (-EBUSY);
}
}
/* Remove directory entry. */
d->d_ino = INODE_NULL;
buf->flags |= BUFFER_DIRTY;
inode_touch(dinode);
file->nlinks--;
inode_touch(file);
inode_put(file);
brelse(buf);
return (0);
}
/**
* @brief Shutdowns the system.
*/
PUBLIC int sys_shutdown(void)
{
/* Not allowed. */
if (!IS_SUPERUSER(curr_proc))
return (-EPERM);
shutting_down = 1;
cdev_ioctl(kout, TTY_CLEAR, 0);
kprintf("system is going to shutdown NOW");
kprintf("synchronizing data...");
sys_sync();
kprintf("asking process to terminate...");
sys_kill(-1, SIGKILL);
return (0);
}
/*
* Checks rwx permissions on a file.
*/
PUBLIC mode_t permission(mode_t mode, uid_t uid, gid_t gid, struct process *proc, mode_t mask, int oreal)
{
mode &= mask;
/* Super user. */
if (IS_SUPERUSER(proc))
mode &= S_IRWXU | S_IRWXG | S_IRWXO;
/* Owner user. */
else if ((proc->uid == uid) || ((!oreal && proc->euid == uid)))
mode &= S_IRWXU | S_IRWXG | S_IRWXO;
/* Owner's group user. */
else if ((proc->gid == gid) || ((!oreal && proc->egid == gid)))
mode &= S_IRWXG | S_IRWXO;
/* Other user. */
else
mode &= S_IRWXO;
return (mode);
}
/*
* Sets the real user ID of the calling process.
*/
PUBLIC int sys_setuid(pid_t uid)
{
/* Superuser authentication. */
if (IS_SUPERUSER(curr_proc))
{
curr_proc->uid = uid;
curr_proc->euid = uid;
curr_proc->suid = uid;
}
else
{
/* User authentication. */
if ((uid == curr_proc->uid) || (uid == curr_proc->suid))
curr_proc->euid = uid;
/* No authentication. */
else
return (-EPERM);
}
return (0);
}
