linux/fs/dlm/user.c
Edwin Török 55acdd926f dlm: avoid double-free on error path in dlm_device_{register,unregister}
Can be reproduced when running dlm_controld (tested on 4.4.x, 4.12.4):
 # seq 1 100 | xargs -P0 -n1 dlm_tool join
 # seq 1 100 | xargs -P0 -n1 dlm_tool leave

misc_register fails due to duplicate sysfs entry, which causes
dlm_device_register to free ls->ls_device.name.
In dlm_device_deregister the name was freed again, causing memory
corruption.

According to the comment in dlm_device_deregister the name should've been
set to NULL when registration fails,
so this patch does that.

sysfs: cannot create duplicate filename '/dev/char/10:1'
------------[ cut here ]------------
warning: cpu: 1 pid: 4450 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x56/0x70
modules linked in: msr rfcomm dlm ccm bnep dm_crypt uvcvideo
videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core videodev
btusb media btrtl btbcm btintel bluetooth ecdh_generic intel_rapl
x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
snd_hda_codec_hdmi irqbypass crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel thinkpad_acpi pcbc nvram snd_seq_midi
snd_seq_midi_event aesni_intel snd_hda_codec_realtek snd_hda_codec_generic
snd_rawmidi aes_x86_64 crypto_simd glue_helper snd_hda_intel snd_hda_codec
cryptd intel_cstate arc4 snd_hda_core snd_seq snd_seq_device snd_hwdep
iwldvm intel_rapl_perf mac80211 joydev input_leds iwlwifi serio_raw
cfg80211 snd_pcm shpchp snd_timer snd mac_hid mei_me lpc_ich mei soundcore
sunrpc parport_pc ppdev lp parport autofs4 i915 psmouse
 e1000e ahci libahci i2c_algo_bit sdhci_pci ptp drm_kms_helper sdhci
pps_core syscopyarea sysfillrect sysimgblt fb_sys_fops drm wmi video
cpu: 1 pid: 4450 comm: dlm_test.exe not tainted 4.12.4-041204-generic
hardware name: lenovo 232425u/232425u, bios g2et82ww (2.02 ) 09/11/2012
task: ffff96b0cbabe140 task.stack: ffffb199027d0000
rip: 0010:sysfs_warn_dup+0x56/0x70
rsp: 0018:ffffb199027d3c58 eflags: 00010282
rax: 0000000000000038 rbx: ffff96b0e2c49158 rcx: 0000000000000006
rdx: 0000000000000000 rsi: 0000000000000086 rdi: ffff96b15e24dcc0
rbp: ffffb199027d3c70 r08: 0000000000000001 r09: 0000000000000721
r10: ffffb199027d3c00 r11: 0000000000000721 r12: ffffb199027d3cd1
r13: ffff96b1592088f0 r14: 0000000000000001 r15: ffffffffffffffef
fs:  00007f78069c0700(0000) gs:ffff96b15e240000(0000)
knlgs:0000000000000000
cs:  0010 ds: 0000 es: 0000 cr0: 0000000080050033
cr2: 000000178625ed28 cr3: 0000000091d3e000 cr4: 00000000001406e0
call trace:
 sysfs_do_create_link_sd.isra.2+0x9e/0xb0
 sysfs_create_link+0x25/0x40
 device_add+0x5a9/0x640
 device_create_groups_vargs+0xe0/0xf0
 device_create_with_groups+0x3f/0x60
 ? snprintf+0x45/0x70
 misc_register+0x140/0x180
 device_write+0x6a8/0x790 [dlm]
 __vfs_write+0x37/0x160
 ? apparmor_file_permission+0x1a/0x20
 ? security_file_permission+0x3b/0xc0
 vfs_write+0xb5/0x1a0
 sys_write+0x55/0xc0
 ? sys_fcntl+0x5d/0xb0
 entry_syscall_64_fastpath+0x1e/0xa9
rip: 0033:0x7f78083454bd
rsp: 002b:00007f78069bbd30 eflags: 00000293 orig_rax: 0000000000000001
rax: ffffffffffffffda rbx: 0000000000000006 rcx: 00007f78083454bd
rdx: 000000000000009c rsi: 00007f78069bee00 rdi: 0000000000000005
rbp: 00007f77f8000a20 r08: 000000000000fcf0 r09: 0000000000000032
r10: 0000000000000024 r11: 0000000000000293 r12: 00007f78069bde00
r13: 00007f78069bee00 r14: 000000000000000a r15: 00007f78069bbd70
code: 85 c0 48 89 c3 74 12 b9 00 10 00 00 48 89 c2 31 f6 4c 89 ef e8 2c c8
ff ff 4c 89 e2 48 89 de 48 c7 c7 b0 8e 0c a8 e8 41 e8 ed ff <0f> ff 48 89
df e8 00 d5 f4 ff 5b 41 5c 41 5d 5d c3 66 0f 1f 84
---[ end trace 40412246357cc9e0 ]---

dlm: 59f24629-ae39-44e2-9030-397ebc2eda26: leaving the lockspace group...
bug: unable to handle kernel null pointer dereference at 0000000000000001
ip: [<ffffffff811a3b4a>] kmem_cache_alloc+0x7a/0x140
pgd 0
oops: 0000 [#1] smp
modules linked in: dlm 8021q garp mrp stp llc openvswitch nf_defrag_ipv6
nf_conntrack libcrc32c iptable_filter dm_multipath crc32_pclmul dm_mod
aesni_intel psmouse aes_x86_64 sg ablk_helper cryptd lrw gf128mul
glue_helper i2c_piix4 nls_utf8 tpm_tis tpm isofs nfsd auth_rpcgss
oid_registry nfs_acl lockd grace sunrpc xen_wdt ip_tables x_tables autofs4
hid_generic usbhid hid sr_mod cdrom sd_mod ata_generic pata_acpi 8139too
serio_raw ata_piix 8139cp mii uhci_hcd ehci_pci ehci_hcd libata
scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh_alua scsi_mod ipv6
cpu: 0 pid: 394 comm: systemd-udevd tainted: g w 4.4.0+0 #1
hardware name: xen hvm domu, bios 4.7.2-2.2 05/11/2017
task: ffff880002410000 ti: ffff88000243c000 task.ti: ffff88000243c000
rip: e030:[<ffffffff811a3b4a>] [<ffffffff811a3b4a>]
kmem_cache_alloc+0x7a/0x140
rsp: e02b:ffff88000243fd90 eflags: 00010202
rax: 0000000000000000 rbx: ffff8800029864d0 rcx: 000000000007b36c
rdx: 000000000007b36b rsi: 00000000024000c0 rdi: ffff880036801c00
rbp: ffff88000243fdc0 r08: 0000000000018880 r09: 0000000000000054
r10: 000000000000004a r11: ffff880034ace6c0 r12: 00000000024000c0
r13: ffff880036801c00 r14: 0000000000000001 r15: ffffffff8118dcc2
fs: 00007f0ab77548c0(0000) gs:ffff880036e00000(0000) knlgs:0000000000000000
cs: e033 ds: 0000 es: 0000 cr0: 0000000080050033
cr2: 0000000000000001 cr3: 000000000332d000 cr4: 0000000000040660
stack:
ffffffff8118dc90 ffff8800029864d0 0000000000000000 ffff88003430b0b0
ffff880034b78320 ffff88003430b0b0 ffff88000243fdf8 ffffffff8118dcc2
ffff8800349c6700 ffff8800029864d0 000000000000000b 00007f0ab7754b90
call trace:
[<ffffffff8118dc90>] ? anon_vma_fork+0x60/0x140
[<ffffffff8118dcc2>] anon_vma_fork+0x92/0x140
[<ffffffff8107033e>] copy_process+0xcae/0x1a80
[<ffffffff8107128b>] _do_fork+0x8b/0x2d0
[<ffffffff81071579>] sys_clone+0x19/0x20
[<ffffffff815a30ae>] entry_syscall_64_fastpath+0x12/0x71
] code: f6 75 1c 4c 89 fa 44 89 e6 4c 89 ef e8 a7 e4 00 00 41 f7 c4 00 80
00 00 49 89 c6 74 47 eb 32 49 63 45 20 48 8d 4a 01 4d 8b 45 00 <49> 8b 1c
06 4c 89 f0 65 49 0f c7 08 0f 94 c0 84 c0 74 ac 49 63
rip [<ffffffff811a3b4a>] kmem_cache_alloc+0x7a/0x140
rsp <ffff88000243fd90>
cr2: 0000000000000001
--[ end trace 70cb9fd1b164a0e8 ]--

CC: stable@vger.kernel.org
Signed-off-by: Edwin Török <edvin.torok@citrix.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2017-08-07 11:23:09 -05:00

1015 lines
24 KiB
C

/*
* Copyright (C) 2006-2010 Red Hat, Inc. All rights reserved.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License v.2.
*/
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/poll.h>
#include <linux/signal.h>
#include <linux/spinlock.h>
#include <linux/dlm.h>
#include <linux/dlm_device.h>
#include <linux/slab.h>
#include <linux/sched/signal.h>
#include "dlm_internal.h"
#include "lockspace.h"
#include "lock.h"
#include "lvb_table.h"
#include "user.h"
#include "ast.h"
static const char name_prefix[] = "dlm";
static const struct file_operations device_fops;
static atomic_t dlm_monitor_opened;
static int dlm_monitor_unused = 1;
#ifdef CONFIG_COMPAT
struct dlm_lock_params32 {
__u8 mode;
__u8 namelen;
__u16 unused;
__u32 flags;
__u32 lkid;
__u32 parent;
__u64 xid;
__u64 timeout;
__u32 castparam;
__u32 castaddr;
__u32 bastparam;
__u32 bastaddr;
__u32 lksb;
char lvb[DLM_USER_LVB_LEN];
char name[0];
};
struct dlm_write_request32 {
__u32 version[3];
__u8 cmd;
__u8 is64bit;
__u8 unused[2];
union {
struct dlm_lock_params32 lock;
struct dlm_lspace_params lspace;
struct dlm_purge_params purge;
} i;
};
struct dlm_lksb32 {
__u32 sb_status;
__u32 sb_lkid;
__u8 sb_flags;
__u32 sb_lvbptr;
};
struct dlm_lock_result32 {
__u32 version[3];
__u32 length;
__u32 user_astaddr;
__u32 user_astparam;
__u32 user_lksb;
struct dlm_lksb32 lksb;
__u8 bast_mode;
__u8 unused[3];
/* Offsets may be zero if no data is present */
__u32 lvb_offset;
};
static void compat_input(struct dlm_write_request *kb,
struct dlm_write_request32 *kb32,
int namelen)
{
kb->version[0] = kb32->version[0];
kb->version[1] = kb32->version[1];
kb->version[2] = kb32->version[2];
kb->cmd = kb32->cmd;
kb->is64bit = kb32->is64bit;
if (kb->cmd == DLM_USER_CREATE_LOCKSPACE ||
kb->cmd == DLM_USER_REMOVE_LOCKSPACE) {
kb->i.lspace.flags = kb32->i.lspace.flags;
kb->i.lspace.minor = kb32->i.lspace.minor;
memcpy(kb->i.lspace.name, kb32->i.lspace.name, namelen);
} else if (kb->cmd == DLM_USER_PURGE) {
kb->i.purge.nodeid = kb32->i.purge.nodeid;
kb->i.purge.pid = kb32->i.purge.pid;
} else {
kb->i.lock.mode = kb32->i.lock.mode;
kb->i.lock.namelen = kb32->i.lock.namelen;
kb->i.lock.flags = kb32->i.lock.flags;
kb->i.lock.lkid = kb32->i.lock.lkid;
kb->i.lock.parent = kb32->i.lock.parent;
kb->i.lock.xid = kb32->i.lock.xid;
kb->i.lock.timeout = kb32->i.lock.timeout;
kb->i.lock.castparam = (void *)(long)kb32->i.lock.castparam;
kb->i.lock.castaddr = (void *)(long)kb32->i.lock.castaddr;
kb->i.lock.bastparam = (void *)(long)kb32->i.lock.bastparam;
kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
memcpy(kb->i.lock.name, kb32->i.lock.name, namelen);
}
}
static void compat_output(struct dlm_lock_result *res,
struct dlm_lock_result32 *res32)
{
memset(res32, 0, sizeof(*res32));
res32->version[0] = res->version[0];
res32->version[1] = res->version[1];
res32->version[2] = res->version[2];
res32->user_astaddr = (__u32)(long)res->user_astaddr;
res32->user_astparam = (__u32)(long)res->user_astparam;
res32->user_lksb = (__u32)(long)res->user_lksb;
res32->bast_mode = res->bast_mode;
res32->lvb_offset = res->lvb_offset;
res32->length = res->length;
res32->lksb.sb_status = res->lksb.sb_status;
res32->lksb.sb_flags = res->lksb.sb_flags;
res32->lksb.sb_lkid = res->lksb.sb_lkid;
res32->lksb.sb_lvbptr = (__u32)(long)res->lksb.sb_lvbptr;
}
#endif
/* Figure out if this lock is at the end of its life and no longer
available for the application to use. The lkb still exists until
the final ast is read. A lock becomes EOL in three situations:
1. a noqueue request fails with EAGAIN
2. an unlock completes with EUNLOCK
3. a cancel of a waiting request completes with ECANCEL/EDEADLK
An EOL lock needs to be removed from the process's list of locks.
And we can't allow any new operation on an EOL lock. This is
not related to the lifetime of the lkb struct which is managed
entirely by refcount. */
static int lkb_is_endoflife(int mode, int status)
{
switch (status) {
case -DLM_EUNLOCK:
return 1;
case -DLM_ECANCEL:
case -ETIMEDOUT:
case -EDEADLK:
case -EAGAIN:
if (mode == DLM_LOCK_IV)
return 1;
break;
}
return 0;
}
/* we could possibly check if the cancel of an orphan has resulted in the lkb
being removed and then remove that lkb from the orphans list and free it */
void dlm_user_add_ast(struct dlm_lkb *lkb, uint32_t flags, int mode,
int status, uint32_t sbflags, uint64_t seq)
{
struct dlm_ls *ls;
struct dlm_user_args *ua;
struct dlm_user_proc *proc;
int rv;
if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
return;
ls = lkb->lkb_resource->res_ls;
mutex_lock(&ls->ls_clear_proc_locks);
/* If ORPHAN/DEAD flag is set, it means the process is dead so an ast
can't be delivered. For ORPHAN's, dlm_clear_proc_locks() freed
lkb->ua so we can't try to use it. This second check is necessary
for cases where a completion ast is received for an operation that
began before clear_proc_locks did its cancel/unlock. */
if (lkb->lkb_flags & (DLM_IFL_ORPHAN | DLM_IFL_DEAD))
goto out;
DLM_ASSERT(lkb->lkb_ua, dlm_print_lkb(lkb););
ua = lkb->lkb_ua;
proc = ua->proc;
if ((flags & DLM_CB_BAST) && ua->bastaddr == NULL)
goto out;
if ((flags & DLM_CB_CAST) && lkb_is_endoflife(mode, status))
lkb->lkb_flags |= DLM_IFL_ENDOFLIFE;
spin_lock(&proc->asts_spin);
rv = dlm_add_lkb_callback(lkb, flags, mode, status, sbflags, seq);
if (rv < 0) {
spin_unlock(&proc->asts_spin);
goto out;
}
if (list_empty(&lkb->lkb_cb_list)) {
kref_get(&lkb->lkb_ref);
list_add_tail(&lkb->lkb_cb_list, &proc->asts);
wake_up_interruptible(&proc->wait);
}
spin_unlock(&proc->asts_spin);
if (lkb->lkb_flags & DLM_IFL_ENDOFLIFE) {
/* N.B. spin_lock locks_spin, not asts_spin */
spin_lock(&proc->locks_spin);
if (!list_empty(&lkb->lkb_ownqueue)) {
list_del_init(&lkb->lkb_ownqueue);
dlm_put_lkb(lkb);
}
spin_unlock(&proc->locks_spin);
}
out:
mutex_unlock(&ls->ls_clear_proc_locks);
}
static int device_user_lock(struct dlm_user_proc *proc,
struct dlm_lock_params *params)
{
struct dlm_ls *ls;
struct dlm_user_args *ua;
uint32_t lkid;
int error = -ENOMEM;
ls = dlm_find_lockspace_local(proc->lockspace);
if (!ls)
return -ENOENT;
if (!params->castaddr || !params->lksb) {
error = -EINVAL;
goto out;
}
ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
if (!ua)
goto out;
ua->proc = proc;
ua->user_lksb = params->lksb;
ua->castparam = params->castparam;
ua->castaddr = params->castaddr;
ua->bastparam = params->bastparam;
ua->bastaddr = params->bastaddr;
ua->xid = params->xid;
if (params->flags & DLM_LKF_CONVERT) {
error = dlm_user_convert(ls, ua,
params->mode, params->flags,
params->lkid, params->lvb,
(unsigned long) params->timeout);
} else if (params->flags & DLM_LKF_ORPHAN) {
error = dlm_user_adopt_orphan(ls, ua,
params->mode, params->flags,
params->name, params->namelen,
(unsigned long) params->timeout,
&lkid);
if (!error)
error = lkid;
} else {
error = dlm_user_request(ls, ua,
params->mode, params->flags,
params->name, params->namelen,
(unsigned long) params->timeout);
if (!error)
error = ua->lksb.sb_lkid;
}
out:
dlm_put_lockspace(ls);
return error;
}
static int device_user_unlock(struct dlm_user_proc *proc,
struct dlm_lock_params *params)
{
struct dlm_ls *ls;
struct dlm_user_args *ua;
int error = -ENOMEM;
ls = dlm_find_lockspace_local(proc->lockspace);
if (!ls)
return -ENOENT;
ua = kzalloc(sizeof(struct dlm_user_args), GFP_NOFS);
if (!ua)
goto out;
ua->proc = proc;
ua->user_lksb = params->lksb;
ua->castparam = params->castparam;
ua->castaddr = params->castaddr;
if (params->flags & DLM_LKF_CANCEL)
error = dlm_user_cancel(ls, ua, params->flags, params->lkid);
else
error = dlm_user_unlock(ls, ua, params->flags, params->lkid,
params->lvb);
out:
dlm_put_lockspace(ls);
return error;
}
static int device_user_deadlock(struct dlm_user_proc *proc,
struct dlm_lock_params *params)
{
struct dlm_ls *ls;
int error;
ls = dlm_find_lockspace_local(proc->lockspace);
if (!ls)
return -ENOENT;
error = dlm_user_deadlock(ls, params->flags, params->lkid);
dlm_put_lockspace(ls);
return error;
}
static int dlm_device_register(struct dlm_ls *ls, char *name)
{
int error, len;
/* The device is already registered. This happens when the
lockspace is created multiple times from userspace. */
if (ls->ls_device.name)
return 0;
error = -ENOMEM;
len = strlen(name) + strlen(name_prefix) + 2;
ls->ls_device.name = kzalloc(len, GFP_NOFS);
if (!ls->ls_device.name)
goto fail;
snprintf((char *)ls->ls_device.name, len, "%s_%s", name_prefix,
name);
ls->ls_device.fops = &device_fops;
ls->ls_device.minor = MISC_DYNAMIC_MINOR;
error = misc_register(&ls->ls_device);
if (error) {
kfree(ls->ls_device.name);
/* this has to be set to NULL
* to avoid a double-free in dlm_device_deregister
*/
ls->ls_device.name = NULL;
}
fail:
return error;
}
int dlm_device_deregister(struct dlm_ls *ls)
{
/* The device is not registered. This happens when the lockspace
was never used from userspace, or when device_create_lockspace()
calls dlm_release_lockspace() after the register fails. */
if (!ls->ls_device.name)
return 0;
misc_deregister(&ls->ls_device);
kfree(ls->ls_device.name);
return 0;
}
static int device_user_purge(struct dlm_user_proc *proc,
struct dlm_purge_params *params)
{
struct dlm_ls *ls;
int error;
ls = dlm_find_lockspace_local(proc->lockspace);
if (!ls)
return -ENOENT;
error = dlm_user_purge(ls, proc, params->nodeid, params->pid);
dlm_put_lockspace(ls);
return error;
}
static int device_create_lockspace(struct dlm_lspace_params *params)
{
dlm_lockspace_t *lockspace;
struct dlm_ls *ls;
int error;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
error = dlm_new_lockspace(params->name, NULL, params->flags,
DLM_USER_LVB_LEN, NULL, NULL, NULL,
&lockspace);
if (error)
return error;
ls = dlm_find_lockspace_local(lockspace);
if (!ls)
return -ENOENT;
error = dlm_device_register(ls, params->name);
dlm_put_lockspace(ls);
if (error)
dlm_release_lockspace(lockspace, 0);
else
error = ls->ls_device.minor;
return error;
}
static int device_remove_lockspace(struct dlm_lspace_params *params)
{
dlm_lockspace_t *lockspace;
struct dlm_ls *ls;
int error, force = 0;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
ls = dlm_find_lockspace_device(params->minor);
if (!ls)
return -ENOENT;
if (params->flags & DLM_USER_LSFLG_FORCEFREE)
force = 2;
lockspace = ls->ls_local_handle;
dlm_put_lockspace(ls);
/* The final dlm_release_lockspace waits for references to go to
zero, so all processes will need to close their device for the
ls before the release will proceed. release also calls the
device_deregister above. Converting a positive return value
from release to zero means that userspace won't know when its
release was the final one, but it shouldn't need to know. */
error = dlm_release_lockspace(lockspace, force);
if (error > 0)
error = 0;
return error;
}
/* Check the user's version matches ours */
static int check_version(struct dlm_write_request *req)
{
if (req->version[0] != DLM_DEVICE_VERSION_MAJOR ||
(req->version[0] == DLM_DEVICE_VERSION_MAJOR &&
req->version[1] > DLM_DEVICE_VERSION_MINOR)) {
printk(KERN_DEBUG "dlm: process %s (%d) version mismatch "
"user (%d.%d.%d) kernel (%d.%d.%d)\n",
current->comm,
task_pid_nr(current),
req->version[0],
req->version[1],
req->version[2],
DLM_DEVICE_VERSION_MAJOR,
DLM_DEVICE_VERSION_MINOR,
DLM_DEVICE_VERSION_PATCH);
return -EINVAL;
}
return 0;
}
/*
* device_write
*
* device_user_lock
* dlm_user_request -> request_lock
* dlm_user_convert -> convert_lock
*
* device_user_unlock
* dlm_user_unlock -> unlock_lock
* dlm_user_cancel -> cancel_lock
*
* device_create_lockspace
* dlm_new_lockspace
*
* device_remove_lockspace
* dlm_release_lockspace
*/
/* a write to a lockspace device is a lock or unlock request, a write
to the control device is to create/remove a lockspace */
static ssize_t device_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct dlm_user_proc *proc = file->private_data;
struct dlm_write_request *kbuf;
int error;
#ifdef CONFIG_COMPAT
if (count < sizeof(struct dlm_write_request32))
#else
if (count < sizeof(struct dlm_write_request))
#endif
return -EINVAL;
/*
* can't compare against COMPAT/dlm_write_request32 because
* we don't yet know if is64bit is zero
*/
if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
return -EINVAL;
kbuf = memdup_user_nul(buf, count);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
if (check_version(kbuf)) {
error = -EBADE;
goto out_free;
}
#ifdef CONFIG_COMPAT
if (!kbuf->is64bit) {
struct dlm_write_request32 *k32buf;
int namelen = 0;
if (count > sizeof(struct dlm_write_request32))
namelen = count - sizeof(struct dlm_write_request32);
k32buf = (struct dlm_write_request32 *)kbuf;
/* add 1 after namelen so that the name string is terminated */
kbuf = kzalloc(sizeof(struct dlm_write_request) + namelen + 1,
GFP_NOFS);
if (!kbuf) {
kfree(k32buf);
return -ENOMEM;
}
if (proc)
set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
compat_input(kbuf, k32buf, namelen);
kfree(k32buf);
}
#endif
/* do we really need this? can a write happen after a close? */
if ((kbuf->cmd == DLM_USER_LOCK || kbuf->cmd == DLM_USER_UNLOCK) &&
(proc && test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))) {
error = -EINVAL;
goto out_free;
}
error = -EINVAL;
switch (kbuf->cmd)
{
case DLM_USER_LOCK:
if (!proc) {
log_print("no locking on control device");
goto out_free;
}
error = device_user_lock(proc, &kbuf->i.lock);
break;
case DLM_USER_UNLOCK:
if (!proc) {
log_print("no locking on control device");
goto out_free;
}
error = device_user_unlock(proc, &kbuf->i.lock);
break;
case DLM_USER_DEADLOCK:
if (!proc) {
log_print("no locking on control device");
goto out_free;
}
error = device_user_deadlock(proc, &kbuf->i.lock);
break;
case DLM_USER_CREATE_LOCKSPACE:
if (proc) {
log_print("create/remove only on control device");
goto out_free;
}
error = device_create_lockspace(&kbuf->i.lspace);
break;
case DLM_USER_REMOVE_LOCKSPACE:
if (proc) {
log_print("create/remove only on control device");
goto out_free;
}
error = device_remove_lockspace(&kbuf->i.lspace);
break;
case DLM_USER_PURGE:
if (!proc) {
log_print("no locking on control device");
goto out_free;
}
error = device_user_purge(proc, &kbuf->i.purge);
break;
default:
log_print("Unknown command passed to DLM device : %d\n",
kbuf->cmd);
}
out_free:
kfree(kbuf);
return error;
}
/* Every process that opens the lockspace device has its own "proc" structure
hanging off the open file that's used to keep track of locks owned by the
process and asts that need to be delivered to the process. */
static int device_open(struct inode *inode, struct file *file)
{
struct dlm_user_proc *proc;
struct dlm_ls *ls;
ls = dlm_find_lockspace_device(iminor(inode));
if (!ls)
return -ENOENT;
proc = kzalloc(sizeof(struct dlm_user_proc), GFP_NOFS);
if (!proc) {
dlm_put_lockspace(ls);
return -ENOMEM;
}
proc->lockspace = ls->ls_local_handle;
INIT_LIST_HEAD(&proc->asts);
INIT_LIST_HEAD(&proc->locks);
INIT_LIST_HEAD(&proc->unlocking);
spin_lock_init(&proc->asts_spin);
spin_lock_init(&proc->locks_spin);
init_waitqueue_head(&proc->wait);
file->private_data = proc;
return 0;
}
static int device_close(struct inode *inode, struct file *file)
{
struct dlm_user_proc *proc = file->private_data;
struct dlm_ls *ls;
ls = dlm_find_lockspace_local(proc->lockspace);
if (!ls)
return -ENOENT;
set_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags);
dlm_clear_proc_locks(ls, proc);
/* at this point no more lkb's should exist for this lockspace,
so there's no chance of dlm_user_add_ast() being called and
looking for lkb->ua->proc */
kfree(proc);
file->private_data = NULL;
dlm_put_lockspace(ls);
dlm_put_lockspace(ls); /* for the find in device_open() */
/* FIXME: AUTOFREE: if this ls is no longer used do
device_remove_lockspace() */
return 0;
}
static int copy_result_to_user(struct dlm_user_args *ua, int compat,
uint32_t flags, int mode, int copy_lvb,
char __user *buf, size_t count)
{
#ifdef CONFIG_COMPAT
struct dlm_lock_result32 result32;
#endif
struct dlm_lock_result result;
void *resultptr;
int error=0;
int len;
int struct_len;
memset(&result, 0, sizeof(struct dlm_lock_result));
result.version[0] = DLM_DEVICE_VERSION_MAJOR;
result.version[1] = DLM_DEVICE_VERSION_MINOR;
result.version[2] = DLM_DEVICE_VERSION_PATCH;
memcpy(&result.lksb, &ua->lksb, sizeof(struct dlm_lksb));
result.user_lksb = ua->user_lksb;
/* FIXME: dlm1 provides for the user's bastparam/addr to not be updated
in a conversion unless the conversion is successful. See code
in dlm_user_convert() for updating ua from ua_tmp. OpenVMS, though,
notes that a new blocking AST address and parameter are set even if
the conversion fails, so maybe we should just do that. */
if (flags & DLM_CB_BAST) {
result.user_astaddr = ua->bastaddr;
result.user_astparam = ua->bastparam;
result.bast_mode = mode;
} else {
result.user_astaddr = ua->castaddr;
result.user_astparam = ua->castparam;
}
#ifdef CONFIG_COMPAT
if (compat)
len = sizeof(struct dlm_lock_result32);
else
#endif
len = sizeof(struct dlm_lock_result);
struct_len = len;
/* copy lvb to userspace if there is one, it's been updated, and
the user buffer has space for it */
if (copy_lvb && ua->lksb.sb_lvbptr && count >= len + DLM_USER_LVB_LEN) {
if (copy_to_user(buf+len, ua->lksb.sb_lvbptr,
DLM_USER_LVB_LEN)) {
error = -EFAULT;
goto out;
}
result.lvb_offset = len;
len += DLM_USER_LVB_LEN;
}
result.length = len;
resultptr = &result;
#ifdef CONFIG_COMPAT
if (compat) {
compat_output(&result, &result32);
resultptr = &result32;
}
#endif
if (copy_to_user(buf, resultptr, struct_len))
error = -EFAULT;
else
error = len;
out:
return error;
}
static int copy_version_to_user(char __user *buf, size_t count)
{
struct dlm_device_version ver;
memset(&ver, 0, sizeof(struct dlm_device_version));
ver.version[0] = DLM_DEVICE_VERSION_MAJOR;
ver.version[1] = DLM_DEVICE_VERSION_MINOR;
ver.version[2] = DLM_DEVICE_VERSION_PATCH;
if (copy_to_user(buf, &ver, sizeof(struct dlm_device_version)))
return -EFAULT;
return sizeof(struct dlm_device_version);
}
/* a read returns a single ast described in a struct dlm_lock_result */
static ssize_t device_read(struct file *file, char __user *buf, size_t count,
loff_t *ppos)
{
struct dlm_user_proc *proc = file->private_data;
struct dlm_lkb *lkb;
DECLARE_WAITQUEUE(wait, current);
struct dlm_callback cb;
int rv, resid, copy_lvb = 0;
int old_mode, new_mode;
if (count == sizeof(struct dlm_device_version)) {
rv = copy_version_to_user(buf, count);
return rv;
}
if (!proc) {
log_print("non-version read from control device %zu", count);
return -EINVAL;
}
#ifdef CONFIG_COMPAT
if (count < sizeof(struct dlm_lock_result32))
#else
if (count < sizeof(struct dlm_lock_result))
#endif
return -EINVAL;
try_another:
/* do we really need this? can a read happen after a close? */
if (test_bit(DLM_PROC_FLAGS_CLOSING, &proc->flags))
return -EINVAL;
spin_lock(&proc->asts_spin);
if (list_empty(&proc->asts)) {
if (file->f_flags & O_NONBLOCK) {
spin_unlock(&proc->asts_spin);
return -EAGAIN;
}
add_wait_queue(&proc->wait, &wait);
repeat:
set_current_state(TASK_INTERRUPTIBLE);
if (list_empty(&proc->asts) && !signal_pending(current)) {
spin_unlock(&proc->asts_spin);
schedule();
spin_lock(&proc->asts_spin);
goto repeat;
}
set_current_state(TASK_RUNNING);
remove_wait_queue(&proc->wait, &wait);
if (signal_pending(current)) {
spin_unlock(&proc->asts_spin);
return -ERESTARTSYS;
}
}
/* if we empty lkb_callbacks, we don't want to unlock the spinlock
without removing lkb_cb_list; so empty lkb_cb_list is always
consistent with empty lkb_callbacks */
lkb = list_entry(proc->asts.next, struct dlm_lkb, lkb_cb_list);
/* rem_lkb_callback sets a new lkb_last_cast */
old_mode = lkb->lkb_last_cast.mode;
rv = dlm_rem_lkb_callback(lkb->lkb_resource->res_ls, lkb, &cb, &resid);
if (rv < 0) {
/* this shouldn't happen; lkb should have been removed from
list when resid was zero */
log_print("dlm_rem_lkb_callback empty %x", lkb->lkb_id);
list_del_init(&lkb->lkb_cb_list);
spin_unlock(&proc->asts_spin);
/* removes ref for proc->asts, may cause lkb to be freed */
dlm_put_lkb(lkb);
goto try_another;
}
if (!resid)
list_del_init(&lkb->lkb_cb_list);
spin_unlock(&proc->asts_spin);
if (cb.flags & DLM_CB_SKIP) {
/* removes ref for proc->asts, may cause lkb to be freed */
if (!resid)
dlm_put_lkb(lkb);
goto try_another;
}
if (cb.flags & DLM_CB_CAST) {
new_mode = cb.mode;
if (!cb.sb_status && lkb->lkb_lksb->sb_lvbptr &&
dlm_lvb_operations[old_mode + 1][new_mode + 1])
copy_lvb = 1;
lkb->lkb_lksb->sb_status = cb.sb_status;
lkb->lkb_lksb->sb_flags = cb.sb_flags;
}
rv = copy_result_to_user(lkb->lkb_ua,
test_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags),
cb.flags, cb.mode, copy_lvb, buf, count);
/* removes ref for proc->asts, may cause lkb to be freed */
if (!resid)
dlm_put_lkb(lkb);
return rv;
}
static unsigned int device_poll(struct file *file, poll_table *wait)
{
struct dlm_user_proc *proc = file->private_data;
poll_wait(file, &proc->wait, wait);
spin_lock(&proc->asts_spin);
if (!list_empty(&proc->asts)) {
spin_unlock(&proc->asts_spin);
return POLLIN | POLLRDNORM;
}
spin_unlock(&proc->asts_spin);
return 0;
}
int dlm_user_daemon_available(void)
{
/* dlm_controld hasn't started (or, has started, but not
properly populated configfs) */
if (!dlm_our_nodeid())
return 0;
/* This is to deal with versions of dlm_controld that don't
know about the monitor device. We assume that if the
dlm_controld was started (above), but the monitor device
was never opened, that it's an old version. dlm_controld
should open the monitor device before populating configfs. */
if (dlm_monitor_unused)
return 1;
return atomic_read(&dlm_monitor_opened) ? 1 : 0;
}
static int ctl_device_open(struct inode *inode, struct file *file)
{
file->private_data = NULL;
return 0;
}
static int ctl_device_close(struct inode *inode, struct file *file)
{
return 0;
}
static int monitor_device_open(struct inode *inode, struct file *file)
{
atomic_inc(&dlm_monitor_opened);
dlm_monitor_unused = 0;
return 0;
}
static int monitor_device_close(struct inode *inode, struct file *file)
{
if (atomic_dec_and_test(&dlm_monitor_opened))
dlm_stop_lockspaces();
return 0;
}
static const struct file_operations device_fops = {
.open = device_open,
.release = device_close,
.read = device_read,
.write = device_write,
.poll = device_poll,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static const struct file_operations ctl_device_fops = {
.open = ctl_device_open,
.release = ctl_device_close,
.read = device_read,
.write = device_write,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static struct miscdevice ctl_device = {
.name = "dlm-control",
.fops = &ctl_device_fops,
.minor = MISC_DYNAMIC_MINOR,
};
static const struct file_operations monitor_device_fops = {
.open = monitor_device_open,
.release = monitor_device_close,
.owner = THIS_MODULE,
.llseek = noop_llseek,
};
static struct miscdevice monitor_device = {
.name = "dlm-monitor",
.fops = &monitor_device_fops,
.minor = MISC_DYNAMIC_MINOR,
};
int __init dlm_user_init(void)
{
int error;
atomic_set(&dlm_monitor_opened, 0);
error = misc_register(&ctl_device);
if (error) {
log_print("misc_register failed for control device");
goto out;
}
error = misc_register(&monitor_device);
if (error) {
log_print("misc_register failed for monitor device");
misc_deregister(&ctl_device);
}
out:
return error;
}
void dlm_user_exit(void)
{
misc_deregister(&ctl_device);
misc_deregister(&monitor_device);
}