fs.c

讲述linux的初始化过程

	u64	f_bavail;
	u64	f_files;
	u64	f_ffree;
	u64	f_favail;
	u32	f_fsid;
	char	f_basetype[16];
	u32	f_flag;
	u32	f_namemax;
	char	f_fstr[32];
	u32	f_filler[16];
};

static int report_statvfs(struct inode *inode, u32 buf)
{
	struct statfs s;
	int error;
	struct sol_statvfs *ss = (struct sol_statvfs *)A(buf);

	error = vfs_statfs(inode->i_sb, &s);
	if (!error) {
		const char *p = inode->i_sb->s_type->name;
		int i = 0;
		int j = strlen (p);
		
		if (j > 15) j = 15;
		if (IS_RDONLY(inode)) i = 1;
		if (IS_NOSUID(inode)) i |= 2;
		if (put_user (s.f_bsize, &ss->f_bsize)		||
		    __put_user (0, &ss->f_frsize)		||
		    __put_user (s.f_blocks, &ss->f_blocks)	||
		    __put_user (s.f_bfree, &ss->f_bfree)	||
		    __put_user (s.f_bavail, &ss->f_bavail)	||
		    __put_user (s.f_files, &ss->f_files)	||
		    __put_user (s.f_ffree, &ss->f_ffree)	||
		    __put_user (s.f_ffree, &ss->f_favail)	||
		    __put_user (R4_DEV(inode->i_sb->s_dev), &ss->f_fsid) ||
		    __copy_to_user (ss->f_basetype,p,j)		||
		    __put_user (0, (char *)&ss->f_basetype[j])	||
		    __put_user (s.f_namelen, &ss->f_namemax)	||
		    __put_user (i, &ss->f_flag)			||		    
		    __clear_user (&ss->f_fstr, 32))
			return -EFAULT;
	}
	return error;
}

static int report_statvfs64(struct inode *inode, u32 buf)
{
	struct statfs s;
	int error;
	struct sol_statvfs64 *ss = (struct sol_statvfs64 *)A(buf);
			
	error = vfs_statfs(inode->i_sb, &s);
	if (!error) {
		const char *p = inode->i_sb->s_type->name;
		int i = 0;
		int j = strlen (p);
		
		if (j > 15) j = 15;
		if (IS_RDONLY(inode)) i = 1;
		if (IS_NOSUID(inode)) i |= 2;
		if (put_user (s.f_bsize, &ss->f_bsize)		||
		    __put_user (0, &ss->f_frsize)		||
		    __put_user (s.f_blocks, &ss->f_blocks)	||
		    __put_user (s.f_bfree, &ss->f_bfree)	||
		    __put_user (s.f_bavail, &ss->f_bavail)	||
		    __put_user (s.f_files, &ss->f_files)	||
		    __put_user (s.f_ffree, &ss->f_ffree)	||
		    __put_user (s.f_ffree, &ss->f_favail)	||
		    __put_user (R4_DEV(inode->i_sb->s_dev), &ss->f_fsid) ||
		    __copy_to_user (ss->f_basetype,p,j)		||
		    __put_user (0, (char *)&ss->f_basetype[j])	||
		    __put_user (s.f_namelen, &ss->f_namemax)	||
		    __put_user (i, &ss->f_flag)			||		    
		    __clear_user (&ss->f_fstr, 32))
			return -EFAULT;
	}
	return error;
}

asmlinkage int solaris_statvfs(u32 path, u32 buf)
{
	struct nameidata nd;
	int error;

	error = user_path_walk((const char *)A(path),&nd);
	if (!error) {
		struct inode * inode = nd.dentry->d_inode;
		error = report_statvfs(inode, buf);
		path_release(&nd);
	}
	return error;
}

asmlinkage int solaris_fstatvfs(unsigned int fd, u32 buf)
{
	struct file * file;
	int error;

	error = -EBADF;
	file = fget(fd);
	if (file) {
		error = report_statvfs(file->f_dentry->d_inode, buf);
		fput(file);
	}

	return error;
}

asmlinkage int solaris_statvfs64(u32 path, u32 buf)
{
	struct nameidata nd;
	int error;

	lock_kernel();
	error = user_path_walk((const char *)A(path), &nd);
	if (!error) {
		struct inode * inode = nd.dentry->d_inode;
		error = report_statvfs64(inode, buf);
		path_release(&nd);
	}
	unlock_kernel();
	return error;
}

asmlinkage int solaris_fstatvfs64(unsigned int fd, u32 buf)
{
	struct file * file;
	int error;

	error = -EBADF;
	file = fget(fd);
	if (file) {
		lock_kernel();
		error = report_statvfs64(file->f_dentry->d_inode, buf);
		unlock_kernel();
		fput(file);
	}
	return error;
}

extern asmlinkage long sparc32_open(const char * filename, int flags, int mode);

asmlinkage int solaris_open(u32 fname, int flags, u32 mode)
{
	const char *filename = (const char *)(long)fname;
	int fl = flags & 0xf;

	/* Translate flags first. */
	if (flags & 0x2000) fl |= O_LARGEFILE;
	if (flags & 0x8050) fl |= O_SYNC;
	if (flags & 0x80) fl |= O_NONBLOCK;
	if (flags & 0x100) fl |= O_CREAT;
	if (flags & 0x200) fl |= O_TRUNC;
	if (flags & 0x400) fl |= O_EXCL;
	if (flags & 0x800) fl |= O_NOCTTY;
	flags = fl;

	return sparc32_open(filename, flags, mode);
}

#define SOL_F_SETLK	6
#define SOL_F_SETLKW	7
#define SOL_F_FREESP    11
#define SOL_F_ISSTREAM  13
#define SOL_F_GETLK     14
#define SOL_F_PRIV      15
#define SOL_F_NPRIV     16
#define SOL_F_QUOTACTL  17
#define SOL_F_BLOCKS    18
#define SOL_F_BLKSIZE   19
#define SOL_F_GETOWN    23
#define SOL_F_SETOWN    24

struct sol_flock {
	short	l_type;
	short	l_whence;
	u32	l_start;
	u32	l_len;
	s32	l_sysid;
	s32	l_pid;
	s32	l_pad[4];
};

asmlinkage int solaris_fcntl(unsigned fd, unsigned cmd, u32 arg)
{
	int (*sys_fcntl)(unsigned,unsigned,unsigned long) = 
		(int (*)(unsigned,unsigned,unsigned long))SYS(fcntl);
	int ret, flags;

	switch (cmd) {
	case F_DUPFD:
	case F_GETFD:
	case F_SETFD: return sys_fcntl(fd, cmd, (unsigned long)arg);
	case F_GETFL:
		flags = sys_fcntl(fd, cmd, 0);
		ret = flags & 0xf;
		if (flags & O_SYNC) ret |= 0x8050;
		if (flags & O_NONBLOCK) ret |= 0x80;
		return ret;
	case F_SETFL:
		flags = arg & 0xf;
		if (arg & 0x8050) flags |= O_SYNC;
		if (arg & 0x80) flags |= O_NONBLOCK;
		return sys_fcntl(fd, cmd, (long)flags);
	case SOL_F_GETLK:
	case SOL_F_SETLK:
	case SOL_F_SETLKW:
		{
			struct flock f;
			mm_segment_t old_fs = get_fs();

			switch (cmd) {
			case SOL_F_GETLK: cmd = F_GETLK; break;
			case SOL_F_SETLK: cmd = F_SETLK; break;
			case SOL_F_SETLKW: cmd = F_SETLKW; break;
			}

			if (get_user (f.l_type, &((struct sol_flock *)A(arg))->l_type) ||
			    __get_user (f.l_whence, &((struct sol_flock *)A(arg))->l_whence) ||
			    __get_user (f.l_start, &((struct sol_flock *)A(arg))->l_start) ||
			    __get_user (f.l_len, &((struct sol_flock *)A(arg))->l_len) ||
			    __get_user (f.l_pid, &((struct sol_flock *)A(arg))->l_sysid))
				return -EFAULT;

			set_fs(KERNEL_DS);
			ret = sys_fcntl(fd, cmd, (unsigned long)&f);
			set_fs(old_fs);

			if (__put_user (f.l_type, &((struct sol_flock *)A(arg))->l_type) ||
			    __put_user (f.l_whence, &((struct sol_flock *)A(arg))->l_whence) ||
			    __put_user (f.l_start, &((struct sol_flock *)A(arg))->l_start) ||
			    __put_user (f.l_len, &((struct sol_flock *)A(arg))->l_len) ||
			    __put_user (f.l_pid, &((struct sol_flock *)A(arg))->l_pid) ||
			    __put_user (0, &((struct sol_flock *)A(arg))->l_sysid))
				return -EFAULT;

			return ret;
		}
	case SOL_F_FREESP:
	        { 
		    int length;
		    int (*sys_newftruncate)(unsigned int, unsigned long)=
			    (int (*)(unsigned int, unsigned long))SYS(ftruncate);

		    if (get_user(length, &((struct sol_flock*)A(arg))->l_start))
			    return -EFAULT;

		    return sys_newftruncate(fd, length);
		}
	};
	return -EINVAL;
}

asmlinkage int solaris_ulimit(int cmd, int val)
{
	switch (cmd) {
	case 1: /* UL_GETFSIZE - in 512B chunks */
		return current->rlim[RLIMIT_FSIZE].rlim_cur >> 9;
	case 2: /* UL_SETFSIZE */
		if ((unsigned long)val > (LONG_MAX>>9)) return -ERANGE;
		val <<= 9;
		lock_kernel();
		if (val > current->rlim[RLIMIT_FSIZE].rlim_max) {
			if (!capable(CAP_SYS_RESOURCE)) {
				unlock_kernel();
				return -EPERM;
			}
			current->rlim[RLIMIT_FSIZE].rlim_max = val;
		}
		current->rlim[RLIMIT_FSIZE].rlim_cur = val;
		unlock_kernel();
		return 0;
	case 3: /* UL_GMEMLIM */
		return current->rlim[RLIMIT_DATA].rlim_cur;
	case 4: /* UL_GDESLIM */
		return NR_OPEN;
	}
	return -EINVAL;
}

/* At least at the time I'm writing this, Linux doesn't have ACLs, so we
   just fake this */
asmlinkage int solaris_acl(u32 filename, int cmd, int nentries, u32 aclbufp)
{
	return -ENOSYS;
}

asmlinkage int solaris_facl(unsigned int fd, int cmd, int nentries, u32 aclbufp)
{
	return -ENOSYS;
}

asmlinkage int solaris_pread(unsigned int fd, char *buf, u32 count, u32 pos)
{
	ssize_t (*sys_pread)(unsigned int, char *, size_t, loff_t) =
		(ssize_t (*)(unsigned int, char *, size_t, loff_t))SYS(pread);
		
	return sys_pread(fd, buf, count, (loff_t)pos);
}

asmlinkage int solaris_pwrite(unsigned int fd, char *buf, u32 count, u32 pos)
{
	ssize_t (*sys_pwrite)(unsigned int, char *, size_t, loff_t) =
		(ssize_t (*)(unsigned int, char *, size_t, loff_t))SYS(pwrite);
		
	return sys_pwrite(fd, buf, count, (loff_t)pos);
}

/* POSIX.1 names */
#define _PC_LINK_MAX    1
#define _PC_MAX_CANON   2
#define _PC_MAX_INPUT   3
#define _PC_NAME_MAX    4
#define _PC_PATH_MAX    5
#define _PC_PIPE_BUF    6
#define _PC_NO_TRUNC    7
#define _PC_VDISABLE    8
#define _PC_CHOWN_RESTRICTED    9
/* POSIX.4 names */
#define _PC_ASYNC_IO    10
#define _PC_PRIO_IO     11
#define _PC_SYNC_IO     12
#define _PC_LAST        12

/* This is not a real and complete implementation yet, just to keep
 * the easy Solaris binaries happy.
 */
asmlinkage int solaris_fpathconf(int fd, int name)
{
	int ret;

	switch(name) {
	case _PC_LINK_MAX:
		ret = LINK_MAX;
		break;
	case _PC_MAX_CANON:
		ret = MAX_CANON;
		break;
	case _PC_MAX_INPUT:
		ret = MAX_INPUT;
		break;
	case _PC_NAME_MAX:
		ret = NAME_MAX;
		break;
	case _PC_PATH_MAX:
		ret = PATH_MAX;
		break;
	case _PC_PIPE_BUF:
		ret = PIPE_BUF;
		break;
	case _PC_CHOWN_RESTRICTED:
		ret = 1;
		break;
	case _PC_NO_TRUNC:
	case _PC_VDISABLE:
		ret = 0;
		break;
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

asmlinkage int solaris_pathconf(u32 path, int name)
{
	return solaris_fpathconf(0, name);
}

/* solaris_llseek returns long long - quite difficult */
asmlinkage long solaris_llseek(struct pt_regs *regs, u32 off_hi, u32 off_lo, int whence)
{
	int (*sys_llseek)(unsigned int, unsigned long, unsigned long, loff_t *, unsigned int) =
		(int (*)(unsigned int, unsigned long, unsigned long, loff_t *, unsigned int))SYS(_llseek);
	int ret;
	mm_segment_t old_fs = get_fs();
	loff_t retval;
	
	set_fs(KERNEL_DS);
	ret = sys_llseek((unsigned int)regs->u_regs[UREG_I0], off_hi, off_lo, &retval, whence);
	set_fs(old_fs);
	if (ret < 0) return ret;
	regs->u_regs[UREG_I1] = (u32)retval;
	return (retval >> 32);
}

/* Have to mask out all but lower 3 bits */
asmlinkage int solaris_access(u32 filename, long mode)
{
	int (*sys_access)(const char *, int) = 
		(int (*)(const char *, int))SYS(access);
		
	return sys_access((const char *)A(filename), mode & 7);
}