Viewing file:  quota.c (4.28 KB) -rw-r--r--
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/*
* Quota code necessary even when VFS quota support is not compiled
* into the kernel. The interesting stuff is over in dquot.c, here
* we have symbols for initial quotactl(2) handling, the sysctl(2)
* variables, etc - things needed even when quota support disabled.
*/
#include <linux/fs.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include <linux/kernel.h>
#include <linux/smp_lock.h>
int nr_dquots, nr_free_dquots;
static struct super_block *
validate_quotactl(int cmd, int type, const char *special, qid_t id)
{
int ret;
kdev_t dev;
mode_t mode;
struct nameidata nd;
struct super_block *sb;
ret = -ENOSYS;
if (cmd == 0x0800 || cmd == 0x1100) /* both were Q_GETSTATS */
goto error;
/* version/compatibility stuff - needs to be early on in the piece */
ret = -EINVAL;
if (cmd == 0x0300 || cmd == 0x0400 || cmd == 0x0500 || cmd == 0x1000
|| cmd < 0x100)
goto error;
if (type >= MAXQUOTAS)
goto error;
ret = -EPERM;
switch (cmd) {
case Q_SYNC:
case Q_GETINFO:
case Q_XGETQSTAT:
break;
case Q_GETQUOTA:
case Q_XGETQUOTA:
if (((type == USRQUOTA && current->euid != id) ||
(type == GRPQUOTA && !in_egroup_p(id))) &&
!capable(CAP_SYS_ADMIN))
goto error;
break;
default:
if (!capable(CAP_SYS_ADMIN))
goto error;
}
ret = -ENODEV;
if (!special)
goto error;
ret = user_path_walk(special, &nd);
if (ret)
goto error;
dev = nd.dentry->d_inode->i_rdev;
mode = nd.dentry->d_inode->i_mode;
path_release(&nd);
ret = -ENOTBLK;
if (!S_ISBLK(mode))
goto error;
ret = -ENODEV;
sb = get_super(dev);
if (!sb)
goto error;
ret = -ENOSYS;
if (!sb->s_qop) {
drop_super(sb);
goto error;
}
return sb;
error:
return ERR_PTR(ret);
}
asmlinkage long
sys_quotactl(int cmd, const char *special, qid_t id, __kernel_caddr_t addr)
{
int ret, cmds, type;
struct super_block *sb;
union {
char *pathname;
unsigned int flags;
struct mem_dqblk mdq;
struct mem_dqinfo info;
struct fs_disk_quota fdq;
struct fs_quota_stat fqs;
} u; /* qualifies valid uses of "addr" */
lock_kernel();
cmds = cmd >> SUBCMDSHIFT;
type = cmd & SUBCMDMASK;
sb = validate_quotactl(cmds, type, special, id);
if (IS_ERR(sb)) {
unlock_kernel();
return PTR_ERR(sb);
}
ret = -EINVAL;
switch (cmds) {
case Q_QUOTAON:
u.pathname = (char *)addr;
if (sb->s_qop->quotaon)
ret = sb->s_qop->quotaon(sb, type, u.pathname);
break;
case Q_QUOTAOFF:
if (sb->s_qop->quotaoff)
ret = sb->s_qop->quotaoff(sb, type);
break;
case Q_SYNC:
if (sb->s_qop->quotasync)
ret = sb->s_qop->quotasync(sb, type);
break;
case Q_GETINFO:
if (sb->s_qop->getinfo)
ret = sb->s_qop->getinfo(sb, type, &u.info);
if (!ret && copy_to_user(addr, &u.info, sizeof(u.info)))
ret = -EFAULT;
break;
case Q_SETINFO:
case Q_SETFLAGS:
case Q_SETGRACE:
if (!sb->s_qop->setinfo)
break;
ret = -EFAULT;
if (copy_from_user(&u.info, addr, sizeof(u.info)))
break;
ret = sb->s_qop->setinfo(sb, type, &u.info, cmds);
break;
case Q_GETQUOTA:
if (sb->s_qop->getdqblk)
ret = sb->s_qop->getdqblk(sb, type, id, &u.mdq);
if (!ret && copy_to_user(addr, &u.mdq, sizeof(u.mdq)))
ret = -EFAULT;
break;
case Q_SETUSE:
case Q_SETQLIM:
case Q_SETQUOTA:
if (!sb->s_qop->setdqblk)
break;
ret = -EFAULT;
if (copy_from_user(&u.mdq, addr, sizeof(u.mdq)))
break;
ret = sb->s_qop->setdqblk(sb, type, id, &u.mdq, cmds);
break;
case Q_XQUOTAON:
case Q_XQUOTAOFF:
case Q_XQUOTARM:
if (!sb->s_qop->setxstate)
break;
ret = -EFAULT;
if (copy_from_user(&u.flags, addr, sizeof(u.flags)))
break;
ret = sb->s_qop->setxstate(sb, u.flags, cmds);
break;
case Q_XGETQSTAT:
if (sb->s_qop->getxstate)
ret = sb->s_qop->getxstate(sb, &u.fqs);
if (!ret && copy_to_user(addr, &u.fqs, sizeof(u.fqs)))
ret = -EFAULT;
break;
case Q_XSETQLIM:
if (!sb->s_qop->setxquota)
break;
ret = -EFAULT;
if (copy_from_user(&u.fdq, addr, sizeof(u.fdq)))
break;
ret = sb->s_qop->setxquota(sb, type, id, &u.fdq);
break;
case Q_XGETQUOTA:
if (sb->s_qop->getxquota)
ret = sb->s_qop->getxquota(sb, type, id, &u.fdq);
if (!ret && copy_to_user(addr, &u.fdq, sizeof(u.fdq)))
ret = -EFAULT;
break;
default:
}
drop_super(sb);
unlock_kernel();
return ret;
}
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