#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/unistd.h>
#include <sys/vnode.h>
#include <sys/vnode_internal.h>
#include <sys/vnode_if.h>
#include <sys/malloc.h>
#include <sys/fcntl.h>
#include <sys/lockf.h>
#if DEAD_CODE
static int maxlockdepth = MAXDEPTH;
#endif
#ifdef LOCKF_DEBUG
#include <sys/sysctl.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
static int lockf_debug = 2;
SYSCTL_INT(_debug, OID_AUTO, lockf_debug, CTLFLAG_RW, &lockf_debug, 0, "");
#endif
MALLOC_DEFINE(M_LOCKF, "lockf", "Byte-range locking structures");
#define NOLOCKF (struct lockf *)0
#define SELF 0x1
#define OTHERS 0x2
#define OFF_MAX 0x7fffffffffffffffULL
static int lf_clearlock(struct lockf *);
static int lf_findoverlap(struct lockf *,
struct lockf *, int, struct lockf ***, struct lockf **);
static struct lockf *
lf_getblock(struct lockf *);
static int lf_getlock(struct lockf *, struct flock *);
static int lf_setlock(struct lockf *);
static void lf_split(struct lockf *, struct lockf *);
static void lf_wakelock(struct lockf *);
int
lf_advlock(ap)
struct vnop_advlock_args *ap;
{
struct vnode *vp = ap->a_vp;
struct flock *fl = ap->a_fl;
vfs_context_t context = ap->a_context;
struct lockf *lock;
off_t start, end, oadd;
u_quad_t size;
int error;
struct lockf **head = &vp->v_lockf;
if (*head == (struct lockf *)0) {
if (ap->a_op != F_SETLK) {
fl->l_type = F_UNLCK;
#ifdef LOCKF_DEBUG
printf("lf_advlock: unlock without lock\n");
#endif
return (0);
}
}
switch (fl->l_whence) {
case SEEK_SET:
case SEEK_CUR:
start = fl->l_start;
break;
case SEEK_END:
if ((error = vnode_size(vp, &size, context)))
{
#ifdef LOCKF_DEBUG
printf("lf_advlock: vnode_getattr failed: %d\n", error);
#endif
return (error);
}
if (size > OFF_MAX ||
(fl->l_start > 0 && size > OFF_MAX - fl->l_start))
return (EOVERFLOW);
start = size + fl->l_start;
break;
default:
#ifdef LOCKF_DEBUG
printf("lf_advlock: unknown whence %d\n", fl->l_whence);
#endif
return (EINVAL);
}
if (start < 0)
{
#ifdef LOCKF_DEBUG
printf("lf_advlock: start < 0 (%qd)\n", start);
#endif
return (EINVAL);
}
if (fl->l_len < 0) {
if (start == 0)
{
#ifdef LOCKF_DEBUG
printf("lf_advlock: len < 0 & start == 0\n");
#endif
return (EINVAL);
}
end = start - 1;
start += fl->l_len;
if (start < 0)
{
#ifdef LOCKF_DEBUG
printf("lf_advlock: start < 0 (%qd)\n", start);
#endif
return (EINVAL);
}
} else if (fl->l_len == 0)
end = -1;
else {
oadd = fl->l_len - 1;
if (oadd > (off_t)(OFF_MAX - start))
{
#ifdef LOCKF_DEBUG
printf("lf_advlock: overflow\n");
#endif
return (EOVERFLOW);
}
end = start + oadd;
}
MALLOC(lock, struct lockf *, sizeof *lock, M_LOCKF, M_WAITOK);
lock->lf_start = start;
lock->lf_end = end;
lock->lf_id = ap->a_id;
lock->lf_vnode = vp;
lock->lf_type = fl->l_type;
lock->lf_head = head;
lock->lf_next = (struct lockf *)0;
TAILQ_INIT(&lock->lf_blkhd);
lock->lf_flags = ap->a_flags;
lck_mtx_lock(&vp->v_lock);
switch(ap->a_op) {
case F_SETLK:
error = lf_setlock(lock);
break;
case F_UNLCK:
error = lf_clearlock(lock);
FREE(lock, M_LOCKF);
break;
case F_GETLK:
error = lf_getlock(lock, fl);
FREE(lock, M_LOCKF);
break;
default:
FREE(lock, M_LOCKF);
error = EINVAL;
break;
}
lck_mtx_unlock(&vp->v_lock);
#ifdef LOCKF_DEBUG
printf("lf_advlock: normal exit: %d\n", error);
#endif
return (error);
}
static int
lf_setlock(lock)
struct lockf *lock;
{
struct lockf *block;
struct lockf **head = lock->lf_head;
struct lockf **prev, *overlap, *ltmp;
static char lockstr[] = "lockf";
int ovcase, priority, needtolink, error;
struct vnode *vp = lock->lf_vnode;
#ifdef LOCKF_DEBUG
if (lockf_debug & 1)
lf_print("lf_setlock", lock);
#endif
priority = PLOCK;
if (lock->lf_type == F_WRLCK)
priority += 4;
priority |= PCATCH;
while ((block = lf_getblock(lock))) {
if ((lock->lf_flags & F_WAIT) == 0) {
FREE(lock, M_LOCKF);
return (EAGAIN);
}
#if DEAD_CODE
if ((lock->lf_flags & F_POSIX) &&
(block->lf_flags & F_POSIX)) {
struct proc *wproc;
struct thread *td;
struct lockf *waitblock;
int i = 0;
wproc = (struct proc *)block->lf_id;
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(wproc, td) {
while (td->td_wchan &&
(td->td_wmesg == lockstr) &&
(i++ < maxlockdepth)) {
waitblock = (struct lockf *)td->td_wchan;
waitblock = waitblock->lf_next;
if ((waitblock->lf_flags & F_POSIX) == 0)
break;
wproc = (struct proc *)waitblock->lf_id;
if (wproc == (struct proc *)lock->lf_id) {
mtx_unlock_spin(&sched_lock);
FREE(lock, M_LOCKF);
return (EDEADLK);
}
}
}
mtx_unlock_spin(&sched_lock);
}
#endif
if ((lock->lf_flags & F_FLOCK) &&
lock->lf_type == F_WRLCK) {
lock->lf_type = F_UNLCK;
(void) lf_clearlock(lock);
lock->lf_type = F_WRLCK;
}
lock->lf_next = block;
TAILQ_INSERT_TAIL(&block->lf_blkhd, lock, lf_block);
#ifdef LOCKF_DEBUG
if (lockf_debug & 1) {
lf_print("lf_setlock: blocking on", block);
lf_printlist("lf_setlock", block);
}
#endif
error = msleep(lock, &vp->v_lock, priority, lockstr, 0);
if (error) {
if (lock->lf_next) {
TAILQ_REMOVE(&lock->lf_next->lf_blkhd, lock, lf_block);
lock->lf_next = NOLOCKF;
}
FREE(lock, M_LOCKF);
return (error);
}
}
prev = head;
block = *head;
needtolink = 1;
for (;;) {
ovcase = lf_findoverlap(block, lock, SELF, &prev, &overlap);
if (ovcase)
block = overlap->lf_next;
switch (ovcase) {
case 0:
if (needtolink) {
*prev = lock;
lock->lf_next = overlap;
}
break;
case 1:
if (lock->lf_type == F_RDLCK &&
overlap->lf_type == F_WRLCK)
lf_wakelock(overlap);
overlap->lf_type = lock->lf_type;
FREE(lock, M_LOCKF);
lock = overlap;
break;
case 2:
if (overlap->lf_type == lock->lf_type) {
FREE(lock, M_LOCKF);
lock = overlap;
break;
}
if (overlap->lf_start == lock->lf_start) {
*prev = lock;
lock->lf_next = overlap;
overlap->lf_start = lock->lf_end + 1;
} else
lf_split(overlap, lock);
lf_wakelock(overlap);
break;
case 3:
if (lock->lf_type == F_RDLCK &&
overlap->lf_type == F_WRLCK) {
lf_wakelock(overlap);
} else {
while (!TAILQ_EMPTY(&overlap->lf_blkhd)) {
ltmp = TAILQ_FIRST(&overlap->lf_blkhd);
TAILQ_REMOVE(&overlap->lf_blkhd, ltmp,
lf_block);
TAILQ_INSERT_TAIL(&lock->lf_blkhd,
ltmp, lf_block);
ltmp->lf_next = lock;
}
}
if (needtolink) {
*prev = lock;
lock->lf_next = overlap->lf_next;
prev = &lock->lf_next;
needtolink = 0;
} else
*prev = overlap->lf_next;
FREE(overlap, M_LOCKF);
continue;
case 4:
lock->lf_next = overlap->lf_next;
overlap->lf_next = lock;
overlap->lf_end = lock->lf_start - 1;
prev = &lock->lf_next;
lf_wakelock(overlap);
needtolink = 0;
continue;
case 5:
if (needtolink) {
*prev = lock;
lock->lf_next = overlap;
}
overlap->lf_start = lock->lf_end + 1;
lf_wakelock(overlap);
break;
}
break;
}
#ifdef LOCKF_DEBUG
if (lockf_debug & 1) {
lf_print("lf_setlock: got the lock", lock);
lf_printlist("lf_setlock", lock);
}
#endif
return (0);
}
static int
lf_clearlock(unlock)
struct lockf *unlock;
{
struct lockf **head = unlock->lf_head;
struct lockf *lf = *head;
struct lockf *overlap, **prev;
int ovcase;
if (lf == NOLOCKF)
return (0);
#ifdef LOCKF_DEBUG
if (unlock->lf_type != F_UNLCK)
panic("lf_clearlock: bad type");
if (lockf_debug & 1)
lf_print("lf_clearlock", unlock);
#endif
prev = head;
while ((ovcase = lf_findoverlap(lf, unlock, SELF, &prev, &overlap))) {
lf_wakelock(overlap);
switch (ovcase) {
case 1:
*prev = overlap->lf_next;
FREE(overlap, M_LOCKF);
break;
case 2:
if (overlap->lf_start == unlock->lf_start) {
overlap->lf_start = unlock->lf_end + 1;
break;
}
lf_split(overlap, unlock);
overlap->lf_next = unlock->lf_next;
break;
case 3:
*prev = overlap->lf_next;
lf = overlap->lf_next;
FREE(overlap, M_LOCKF);
continue;
case 4:
overlap->lf_end = unlock->lf_start - 1;
prev = &overlap->lf_next;
lf = overlap->lf_next;
continue;
case 5:
overlap->lf_start = unlock->lf_end + 1;
break;
}
break;
}
#ifdef LOCKF_DEBUG
if (lockf_debug & 1)
lf_printlist("lf_clearlock", unlock);
#endif
return (0);
}
static int
lf_getlock(lock, fl)
struct lockf *lock;
struct flock *fl;
{
struct lockf *block;
#ifdef LOCKF_DEBUG
if (lockf_debug & 1)
lf_print("lf_getlock", lock);
#endif
if ((block = lf_getblock(lock))) {
fl->l_type = block->lf_type;
fl->l_whence = SEEK_SET;
fl->l_start = block->lf_start;
if (block->lf_end == -1)
fl->l_len = 0;
else
fl->l_len = block->lf_end - block->lf_start + 1;
if (block->lf_flags & F_POSIX)
fl->l_pid = proc_pid((struct proc *)(block->lf_id));
else
fl->l_pid = -1;
} else {
fl->l_type = F_UNLCK;
}
return (0);
}
static struct lockf *
lf_getblock(lock)
struct lockf *lock;
{
struct lockf **prev, *overlap, *lf = *(lock->lf_head);
int ovcase;
prev = lock->lf_head;
while ((ovcase = lf_findoverlap(lf, lock, OTHERS, &prev, &overlap))) {
if ((lock->lf_type == F_WRLCK || overlap->lf_type == F_WRLCK))
return (overlap);
lf = overlap->lf_next;
}
return (NOLOCKF);
}
static int
lf_findoverlap(lf, lock, type, prev, overlap)
struct lockf *lf;
struct lockf *lock;
int type;
struct lockf ***prev;
struct lockf **overlap;
{
off_t start, end;
*overlap = lf;
if (lf == NOLOCKF)
return (0);
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
lf_print("lf_findoverlap: looking for overlap in", lock);
#endif
start = lock->lf_start;
end = lock->lf_end;
while (lf != NOLOCKF) {
if (((type & SELF) && lf->lf_id != lock->lf_id) ||
((type & OTHERS) && lf->lf_id == lock->lf_id)) {
*prev = &lf->lf_next;
*overlap = lf = lf->lf_next;
continue;
}
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
lf_print("\tchecking", lf);
#endif
if ((lf->lf_end != -1 && start > lf->lf_end) ||
(end != -1 && lf->lf_start > end)) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("no overlap\n");
#endif
if ((type & SELF) && end != -1 && lf->lf_start > end)
return (0);
*prev = &lf->lf_next;
*overlap = lf = lf->lf_next;
continue;
}
if ((lf->lf_start == start) && (lf->lf_end == end)) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("overlap == lock\n");
#endif
return (1);
}
if ((lf->lf_start <= start) &&
(end != -1) &&
((lf->lf_end >= end) || (lf->lf_end == -1))) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("overlap contains lock\n");
#endif
return (2);
}
if (start <= lf->lf_start &&
(end == -1 ||
(lf->lf_end != -1 && end >= lf->lf_end))) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("lock contains overlap\n");
#endif
return (3);
}
if ((lf->lf_start < start) &&
((lf->lf_end >= start) || (lf->lf_end == -1))) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("overlap starts before lock\n");
#endif
return (4);
}
if ((lf->lf_start > start) &&
(end != -1) &&
((lf->lf_end > end) || (lf->lf_end == -1))) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
printf("overlap ends after lock\n");
#endif
return (5);
}
panic("lf_findoverlap: default");
}
return (0);
}
static void
lf_split(lock1, lock2)
struct lockf *lock1;
struct lockf *lock2;
{
struct lockf *splitlock;
#ifdef LOCKF_DEBUG
if (lockf_debug & 2) {
lf_print("lf_split", lock1);
lf_print("splitting from", lock2);
}
#endif
if (lock1->lf_start == lock2->lf_start) {
lock1->lf_start = lock2->lf_end + 1;
lock2->lf_next = lock1;
return;
}
if (lock1->lf_end == lock2->lf_end) {
lock1->lf_end = lock2->lf_start - 1;
lock2->lf_next = lock1->lf_next;
lock1->lf_next = lock2;
return;
}
MALLOC(splitlock, struct lockf *, sizeof *splitlock, M_LOCKF, M_WAITOK);
bcopy(lock1, splitlock, sizeof *splitlock);
splitlock->lf_start = lock2->lf_end + 1;
TAILQ_INIT(&splitlock->lf_blkhd);
lock1->lf_end = lock2->lf_start - 1;
splitlock->lf_next = lock1->lf_next;
lock2->lf_next = splitlock;
lock1->lf_next = lock2;
}
static void
lf_wakelock(listhead)
struct lockf *listhead;
{
struct lockf *wakelock;
while (!TAILQ_EMPTY(&listhead->lf_blkhd)) {
wakelock = TAILQ_FIRST(&listhead->lf_blkhd);
TAILQ_REMOVE(&listhead->lf_blkhd, wakelock, lf_block);
wakelock->lf_next = NOLOCKF;
#ifdef LOCKF_DEBUG
if (lockf_debug & 2)
lf_print("lf_wakelock: awakening", wakelock);
#endif
wakeup(wakelock);
}
}
#ifdef LOCKF_DEBUG
void
lf_print(tag, lock)
char *tag;
struct lockf *lock;
{
printf("%s: lock %p for ", tag, (void *)lock);
if (lock->lf_flags & F_POSIX)
printf("proc %ld", (long)((struct proc *)lock->lf_id)->p_pid);
else
printf("id %p", (void *)lock->lf_id);
if (lock->lf_vnode != 0)
printf(" in vno 0x%08x, %s, start %jd, end %jd",
lock->lf_vnode,
lock->lf_type == F_RDLCK ? "shared" :
lock->lf_type == F_WRLCK ? "exclusive" :
lock->lf_type == F_UNLCK ? "unlock" : "unknown",
(intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
else
printf(" %s, start %jd, end %jd",
lock->lf_type == F_RDLCK ? "shared" :
lock->lf_type == F_WRLCK ? "exclusive" :
lock->lf_type == F_UNLCK ? "unlock" : "unknown",
(intmax_t)lock->lf_start, (intmax_t)lock->lf_end);
if (!TAILQ_EMPTY(&lock->lf_blkhd))
printf(" block %p\n", (void *)TAILQ_FIRST(&lock->lf_blkhd));
else
printf("\n");
}
void
lf_printlist(tag, lock)
char *tag;
struct lockf *lock;
{
struct lockf *lf, *blk;
if (lock->lf_vnode == 0)
return;
printf("%s: Lock list for vno 0x%08x:\n",
tag, lock->lf_vnode);
for (lf = lock->lf_vnode->v_lockf; lf; lf = lf->lf_next) {
printf("\tlock %p for ",(void *)lf);
if (lf->lf_flags & F_POSIX)
printf("proc %ld",
(long)((struct proc *)lf->lf_id)->p_pid);
else
printf("id %p", (void *)lf->lf_id);
printf(", %s, start %jd, end %jd",
lf->lf_type == F_RDLCK ? "shared" :
lf->lf_type == F_WRLCK ? "exclusive" :
lf->lf_type == F_UNLCK ? "unlock" :
"unknown", (intmax_t)lf->lf_start, (intmax_t)lf->lf_end);
TAILQ_FOREACH(blk, &lf->lf_blkhd, lf_block) {
printf("\n\t\tlock request %p for ", (void *)blk);
if (blk->lf_flags & F_POSIX)
printf("proc %ld",
(long)((struct proc *)blk->lf_id)->p_pid);
else
printf("id %p", (void *)blk->lf_id);
printf(", %s, start %jd, end %jd",
blk->lf_type == F_RDLCK ? "shared" :
blk->lf_type == F_WRLCK ? "exclusive" :
blk->lf_type == F_UNLCK ? "unlock" :
"unknown", (intmax_t)blk->lf_start,
(intmax_t)blk->lf_end);
if (!TAILQ_EMPTY(&blk->lf_blkhd))
panic("lf_printlist: bad list");
}
printf("\n");
}
}
#endif