mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
![Deepa Dinamani](/assets/img/avatar_default.png)
struct timespec is not y2038 safe. Even though timespec might be sufficient to represent timeouts, use struct timespec64 here as the plan is to get rid of all timespec reference in the kernel. The patch transitions the common functions: poll_select_set_timeout() and select_estimate_accuracy() to use timespec64. And, all the syscalls that use these functions are transitioned in the same patch. The restart block parameters for poll uses monotonic time. Use timespec64 here as well to assign timeout value. This parameter in the restart block need not change because this only holds the monotonic timestamp at which timeout should occur. And, unsigned long data type should be big enough for this timestamp. The system call interfaces will be handled in a separate series. Compat interfaces need not change as timespec64 is an alias to struct timespec on a 64 bit system. Link: http://lkml.kernel.org/r/1461947989-21926-3-git-send-email-deepa.kernel@gmail.com Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: John Stultz <john.stultz@linaro.org> Acked-by: David S. Miller <davem@davemloft.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1047 lines
26 KiB
C
1047 lines
26 KiB
C
/*
|
|
* This file contains the procedures for the handling of select and poll
|
|
*
|
|
* Created for Linux based loosely upon Mathius Lattner's minix
|
|
* patches by Peter MacDonald. Heavily edited by Linus.
|
|
*
|
|
* 4 February 1994
|
|
* COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
|
|
* flag set in its personality we do *not* modify the given timeout
|
|
* parameter to reflect time remaining.
|
|
*
|
|
* 24 January 2000
|
|
* Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
|
|
* of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/export.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/poll.h>
|
|
#include <linux/personality.h> /* for STICKY_TIMEOUTS */
|
|
#include <linux/file.h>
|
|
#include <linux/fdtable.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/rcupdate.h>
|
|
#include <linux/hrtimer.h>
|
|
#include <linux/sched/rt.h>
|
|
#include <linux/freezer.h>
|
|
#include <net/busy_poll.h>
|
|
|
|
#include <asm/uaccess.h>
|
|
|
|
|
|
/*
|
|
* Estimate expected accuracy in ns from a timeval.
|
|
*
|
|
* After quite a bit of churning around, we've settled on
|
|
* a simple thing of taking 0.1% of the timeout as the
|
|
* slack, with a cap of 100 msec.
|
|
* "nice" tasks get a 0.5% slack instead.
|
|
*
|
|
* Consider this comment an open invitation to come up with even
|
|
* better solutions..
|
|
*/
|
|
|
|
#define MAX_SLACK (100 * NSEC_PER_MSEC)
|
|
|
|
static long __estimate_accuracy(struct timespec64 *tv)
|
|
{
|
|
long slack;
|
|
int divfactor = 1000;
|
|
|
|
if (tv->tv_sec < 0)
|
|
return 0;
|
|
|
|
if (task_nice(current) > 0)
|
|
divfactor = divfactor / 5;
|
|
|
|
if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
|
|
return MAX_SLACK;
|
|
|
|
slack = tv->tv_nsec / divfactor;
|
|
slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
|
|
|
|
if (slack > MAX_SLACK)
|
|
return MAX_SLACK;
|
|
|
|
return slack;
|
|
}
|
|
|
|
u64 select_estimate_accuracy(struct timespec64 *tv)
|
|
{
|
|
u64 ret;
|
|
struct timespec64 now;
|
|
|
|
/*
|
|
* Realtime tasks get a slack of 0 for obvious reasons.
|
|
*/
|
|
|
|
if (rt_task(current))
|
|
return 0;
|
|
|
|
ktime_get_ts64(&now);
|
|
now = timespec64_sub(*tv, now);
|
|
ret = __estimate_accuracy(&now);
|
|
if (ret < current->timer_slack_ns)
|
|
return current->timer_slack_ns;
|
|
return ret;
|
|
}
|
|
|
|
|
|
|
|
struct poll_table_page {
|
|
struct poll_table_page * next;
|
|
struct poll_table_entry * entry;
|
|
struct poll_table_entry entries[0];
|
|
};
|
|
|
|
#define POLL_TABLE_FULL(table) \
|
|
((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
|
|
|
|
/*
|
|
* Ok, Peter made a complicated, but straightforward multiple_wait() function.
|
|
* I have rewritten this, taking some shortcuts: This code may not be easy to
|
|
* follow, but it should be free of race-conditions, and it's practical. If you
|
|
* understand what I'm doing here, then you understand how the linux
|
|
* sleep/wakeup mechanism works.
|
|
*
|
|
* Two very simple procedures, poll_wait() and poll_freewait() make all the
|
|
* work. poll_wait() is an inline-function defined in <linux/poll.h>,
|
|
* as all select/poll functions have to call it to add an entry to the
|
|
* poll table.
|
|
*/
|
|
static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
|
|
poll_table *p);
|
|
|
|
void poll_initwait(struct poll_wqueues *pwq)
|
|
{
|
|
init_poll_funcptr(&pwq->pt, __pollwait);
|
|
pwq->polling_task = current;
|
|
pwq->triggered = 0;
|
|
pwq->error = 0;
|
|
pwq->table = NULL;
|
|
pwq->inline_index = 0;
|
|
}
|
|
EXPORT_SYMBOL(poll_initwait);
|
|
|
|
static void free_poll_entry(struct poll_table_entry *entry)
|
|
{
|
|
remove_wait_queue(entry->wait_address, &entry->wait);
|
|
fput(entry->filp);
|
|
}
|
|
|
|
void poll_freewait(struct poll_wqueues *pwq)
|
|
{
|
|
struct poll_table_page * p = pwq->table;
|
|
int i;
|
|
for (i = 0; i < pwq->inline_index; i++)
|
|
free_poll_entry(pwq->inline_entries + i);
|
|
while (p) {
|
|
struct poll_table_entry * entry;
|
|
struct poll_table_page *old;
|
|
|
|
entry = p->entry;
|
|
do {
|
|
entry--;
|
|
free_poll_entry(entry);
|
|
} while (entry > p->entries);
|
|
old = p;
|
|
p = p->next;
|
|
free_page((unsigned long) old);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(poll_freewait);
|
|
|
|
static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
|
|
{
|
|
struct poll_table_page *table = p->table;
|
|
|
|
if (p->inline_index < N_INLINE_POLL_ENTRIES)
|
|
return p->inline_entries + p->inline_index++;
|
|
|
|
if (!table || POLL_TABLE_FULL(table)) {
|
|
struct poll_table_page *new_table;
|
|
|
|
new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
|
|
if (!new_table) {
|
|
p->error = -ENOMEM;
|
|
return NULL;
|
|
}
|
|
new_table->entry = new_table->entries;
|
|
new_table->next = table;
|
|
p->table = new_table;
|
|
table = new_table;
|
|
}
|
|
|
|
return table->entry++;
|
|
}
|
|
|
|
static int __pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
|
|
{
|
|
struct poll_wqueues *pwq = wait->private;
|
|
DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
|
|
|
|
/*
|
|
* Although this function is called under waitqueue lock, LOCK
|
|
* doesn't imply write barrier and the users expect write
|
|
* barrier semantics on wakeup functions. The following
|
|
* smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
|
|
* and is paired with smp_store_mb() in poll_schedule_timeout.
|
|
*/
|
|
smp_wmb();
|
|
pwq->triggered = 1;
|
|
|
|
/*
|
|
* Perform the default wake up operation using a dummy
|
|
* waitqueue.
|
|
*
|
|
* TODO: This is hacky but there currently is no interface to
|
|
* pass in @sync. @sync is scheduled to be removed and once
|
|
* that happens, wake_up_process() can be used directly.
|
|
*/
|
|
return default_wake_function(&dummy_wait, mode, sync, key);
|
|
}
|
|
|
|
static int pollwake(wait_queue_t *wait, unsigned mode, int sync, void *key)
|
|
{
|
|
struct poll_table_entry *entry;
|
|
|
|
entry = container_of(wait, struct poll_table_entry, wait);
|
|
if (key && !((unsigned long)key & entry->key))
|
|
return 0;
|
|
return __pollwake(wait, mode, sync, key);
|
|
}
|
|
|
|
/* Add a new entry */
|
|
static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
|
|
poll_table *p)
|
|
{
|
|
struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
|
|
struct poll_table_entry *entry = poll_get_entry(pwq);
|
|
if (!entry)
|
|
return;
|
|
entry->filp = get_file(filp);
|
|
entry->wait_address = wait_address;
|
|
entry->key = p->_key;
|
|
init_waitqueue_func_entry(&entry->wait, pollwake);
|
|
entry->wait.private = pwq;
|
|
add_wait_queue(wait_address, &entry->wait);
|
|
}
|
|
|
|
int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
|
|
ktime_t *expires, unsigned long slack)
|
|
{
|
|
int rc = -EINTR;
|
|
|
|
set_current_state(state);
|
|
if (!pwq->triggered)
|
|
rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
|
|
__set_current_state(TASK_RUNNING);
|
|
|
|
/*
|
|
* Prepare for the next iteration.
|
|
*
|
|
* The following smp_store_mb() serves two purposes. First, it's
|
|
* the counterpart rmb of the wmb in pollwake() such that data
|
|
* written before wake up is always visible after wake up.
|
|
* Second, the full barrier guarantees that triggered clearing
|
|
* doesn't pass event check of the next iteration. Note that
|
|
* this problem doesn't exist for the first iteration as
|
|
* add_wait_queue() has full barrier semantics.
|
|
*/
|
|
smp_store_mb(pwq->triggered, 0);
|
|
|
|
return rc;
|
|
}
|
|
EXPORT_SYMBOL(poll_schedule_timeout);
|
|
|
|
/**
|
|
* poll_select_set_timeout - helper function to setup the timeout value
|
|
* @to: pointer to timespec64 variable for the final timeout
|
|
* @sec: seconds (from user space)
|
|
* @nsec: nanoseconds (from user space)
|
|
*
|
|
* Note, we do not use a timespec for the user space value here, That
|
|
* way we can use the function for timeval and compat interfaces as well.
|
|
*
|
|
* Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
|
|
*/
|
|
int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
|
|
{
|
|
struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
|
|
|
|
if (!timespec64_valid(&ts))
|
|
return -EINVAL;
|
|
|
|
/* Optimize for the zero timeout value here */
|
|
if (!sec && !nsec) {
|
|
to->tv_sec = to->tv_nsec = 0;
|
|
} else {
|
|
ktime_get_ts64(to);
|
|
*to = timespec64_add_safe(*to, ts);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int poll_select_copy_remaining(struct timespec64 *end_time,
|
|
void __user *p,
|
|
int timeval, int ret)
|
|
{
|
|
struct timespec64 rts64;
|
|
struct timespec rts;
|
|
struct timeval rtv;
|
|
|
|
if (!p)
|
|
return ret;
|
|
|
|
if (current->personality & STICKY_TIMEOUTS)
|
|
goto sticky;
|
|
|
|
/* No update for zero timeout */
|
|
if (!end_time->tv_sec && !end_time->tv_nsec)
|
|
return ret;
|
|
|
|
ktime_get_ts64(&rts64);
|
|
rts64 = timespec64_sub(*end_time, rts64);
|
|
if (rts64.tv_sec < 0)
|
|
rts64.tv_sec = rts64.tv_nsec = 0;
|
|
|
|
rts = timespec64_to_timespec(rts64);
|
|
|
|
if (timeval) {
|
|
if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
|
|
memset(&rtv, 0, sizeof(rtv));
|
|
rtv.tv_sec = rts64.tv_sec;
|
|
rtv.tv_usec = rts64.tv_nsec / NSEC_PER_USEC;
|
|
|
|
if (!copy_to_user(p, &rtv, sizeof(rtv)))
|
|
return ret;
|
|
|
|
} else if (!copy_to_user(p, &rts, sizeof(rts)))
|
|
return ret;
|
|
|
|
/*
|
|
* If an application puts its timeval in read-only memory, we
|
|
* don't want the Linux-specific update to the timeval to
|
|
* cause a fault after the select has completed
|
|
* successfully. However, because we're not updating the
|
|
* timeval, we can't restart the system call.
|
|
*/
|
|
|
|
sticky:
|
|
if (ret == -ERESTARTNOHAND)
|
|
ret = -EINTR;
|
|
return ret;
|
|
}
|
|
|
|
#define FDS_IN(fds, n) (fds->in + n)
|
|
#define FDS_OUT(fds, n) (fds->out + n)
|
|
#define FDS_EX(fds, n) (fds->ex + n)
|
|
|
|
#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
|
|
|
|
static int max_select_fd(unsigned long n, fd_set_bits *fds)
|
|
{
|
|
unsigned long *open_fds;
|
|
unsigned long set;
|
|
int max;
|
|
struct fdtable *fdt;
|
|
|
|
/* handle last in-complete long-word first */
|
|
set = ~(~0UL << (n & (BITS_PER_LONG-1)));
|
|
n /= BITS_PER_LONG;
|
|
fdt = files_fdtable(current->files);
|
|
open_fds = fdt->open_fds + n;
|
|
max = 0;
|
|
if (set) {
|
|
set &= BITS(fds, n);
|
|
if (set) {
|
|
if (!(set & ~*open_fds))
|
|
goto get_max;
|
|
return -EBADF;
|
|
}
|
|
}
|
|
while (n) {
|
|
open_fds--;
|
|
n--;
|
|
set = BITS(fds, n);
|
|
if (!set)
|
|
continue;
|
|
if (set & ~*open_fds)
|
|
return -EBADF;
|
|
if (max)
|
|
continue;
|
|
get_max:
|
|
do {
|
|
max++;
|
|
set >>= 1;
|
|
} while (set);
|
|
max += n * BITS_PER_LONG;
|
|
}
|
|
|
|
return max;
|
|
}
|
|
|
|
#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
|
|
#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
|
|
#define POLLEX_SET (POLLPRI)
|
|
|
|
static inline void wait_key_set(poll_table *wait, unsigned long in,
|
|
unsigned long out, unsigned long bit,
|
|
unsigned int ll_flag)
|
|
{
|
|
wait->_key = POLLEX_SET | ll_flag;
|
|
if (in & bit)
|
|
wait->_key |= POLLIN_SET;
|
|
if (out & bit)
|
|
wait->_key |= POLLOUT_SET;
|
|
}
|
|
|
|
int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
|
|
{
|
|
ktime_t expire, *to = NULL;
|
|
struct poll_wqueues table;
|
|
poll_table *wait;
|
|
int retval, i, timed_out = 0;
|
|
u64 slack = 0;
|
|
unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
|
|
unsigned long busy_end = 0;
|
|
|
|
rcu_read_lock();
|
|
retval = max_select_fd(n, fds);
|
|
rcu_read_unlock();
|
|
|
|
if (retval < 0)
|
|
return retval;
|
|
n = retval;
|
|
|
|
poll_initwait(&table);
|
|
wait = &table.pt;
|
|
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
|
|
wait->_qproc = NULL;
|
|
timed_out = 1;
|
|
}
|
|
|
|
if (end_time && !timed_out)
|
|
slack = select_estimate_accuracy(end_time);
|
|
|
|
retval = 0;
|
|
for (;;) {
|
|
unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
|
|
bool can_busy_loop = false;
|
|
|
|
inp = fds->in; outp = fds->out; exp = fds->ex;
|
|
rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
|
|
|
|
for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
|
|
unsigned long in, out, ex, all_bits, bit = 1, mask, j;
|
|
unsigned long res_in = 0, res_out = 0, res_ex = 0;
|
|
|
|
in = *inp++; out = *outp++; ex = *exp++;
|
|
all_bits = in | out | ex;
|
|
if (all_bits == 0) {
|
|
i += BITS_PER_LONG;
|
|
continue;
|
|
}
|
|
|
|
for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
|
|
struct fd f;
|
|
if (i >= n)
|
|
break;
|
|
if (!(bit & all_bits))
|
|
continue;
|
|
f = fdget(i);
|
|
if (f.file) {
|
|
const struct file_operations *f_op;
|
|
f_op = f.file->f_op;
|
|
mask = DEFAULT_POLLMASK;
|
|
if (f_op->poll) {
|
|
wait_key_set(wait, in, out,
|
|
bit, busy_flag);
|
|
mask = (*f_op->poll)(f.file, wait);
|
|
}
|
|
fdput(f);
|
|
if ((mask & POLLIN_SET) && (in & bit)) {
|
|
res_in |= bit;
|
|
retval++;
|
|
wait->_qproc = NULL;
|
|
}
|
|
if ((mask & POLLOUT_SET) && (out & bit)) {
|
|
res_out |= bit;
|
|
retval++;
|
|
wait->_qproc = NULL;
|
|
}
|
|
if ((mask & POLLEX_SET) && (ex & bit)) {
|
|
res_ex |= bit;
|
|
retval++;
|
|
wait->_qproc = NULL;
|
|
}
|
|
/* got something, stop busy polling */
|
|
if (retval) {
|
|
can_busy_loop = false;
|
|
busy_flag = 0;
|
|
|
|
/*
|
|
* only remember a returned
|
|
* POLL_BUSY_LOOP if we asked for it
|
|
*/
|
|
} else if (busy_flag & mask)
|
|
can_busy_loop = true;
|
|
|
|
}
|
|
}
|
|
if (res_in)
|
|
*rinp = res_in;
|
|
if (res_out)
|
|
*routp = res_out;
|
|
if (res_ex)
|
|
*rexp = res_ex;
|
|
cond_resched();
|
|
}
|
|
wait->_qproc = NULL;
|
|
if (retval || timed_out || signal_pending(current))
|
|
break;
|
|
if (table.error) {
|
|
retval = table.error;
|
|
break;
|
|
}
|
|
|
|
/* only if found POLL_BUSY_LOOP sockets && not out of time */
|
|
if (can_busy_loop && !need_resched()) {
|
|
if (!busy_end) {
|
|
busy_end = busy_loop_end_time();
|
|
continue;
|
|
}
|
|
if (!busy_loop_timeout(busy_end))
|
|
continue;
|
|
}
|
|
busy_flag = 0;
|
|
|
|
/*
|
|
* If this is the first loop and we have a timeout
|
|
* given, then we convert to ktime_t and set the to
|
|
* pointer to the expiry value.
|
|
*/
|
|
if (end_time && !to) {
|
|
expire = timespec64_to_ktime(*end_time);
|
|
to = &expire;
|
|
}
|
|
|
|
if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
|
|
to, slack))
|
|
timed_out = 1;
|
|
}
|
|
|
|
poll_freewait(&table);
|
|
|
|
return retval;
|
|
}
|
|
|
|
/*
|
|
* We can actually return ERESTARTSYS instead of EINTR, but I'd
|
|
* like to be certain this leads to no problems. So I return
|
|
* EINTR just for safety.
|
|
*
|
|
* Update: ERESTARTSYS breaks at least the xview clock binary, so
|
|
* I'm trying ERESTARTNOHAND which restart only when you want to.
|
|
*/
|
|
int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
|
|
fd_set __user *exp, struct timespec64 *end_time)
|
|
{
|
|
fd_set_bits fds;
|
|
void *bits;
|
|
int ret, max_fds;
|
|
unsigned int size;
|
|
struct fdtable *fdt;
|
|
/* Allocate small arguments on the stack to save memory and be faster */
|
|
long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
|
|
|
|
ret = -EINVAL;
|
|
if (n < 0)
|
|
goto out_nofds;
|
|
|
|
/* max_fds can increase, so grab it once to avoid race */
|
|
rcu_read_lock();
|
|
fdt = files_fdtable(current->files);
|
|
max_fds = fdt->max_fds;
|
|
rcu_read_unlock();
|
|
if (n > max_fds)
|
|
n = max_fds;
|
|
|
|
/*
|
|
* We need 6 bitmaps (in/out/ex for both incoming and outgoing),
|
|
* since we used fdset we need to allocate memory in units of
|
|
* long-words.
|
|
*/
|
|
size = FDS_BYTES(n);
|
|
bits = stack_fds;
|
|
if (size > sizeof(stack_fds) / 6) {
|
|
/* Not enough space in on-stack array; must use kmalloc */
|
|
ret = -ENOMEM;
|
|
bits = kmalloc(6 * size, GFP_KERNEL);
|
|
if (!bits)
|
|
goto out_nofds;
|
|
}
|
|
fds.in = bits;
|
|
fds.out = bits + size;
|
|
fds.ex = bits + 2*size;
|
|
fds.res_in = bits + 3*size;
|
|
fds.res_out = bits + 4*size;
|
|
fds.res_ex = bits + 5*size;
|
|
|
|
if ((ret = get_fd_set(n, inp, fds.in)) ||
|
|
(ret = get_fd_set(n, outp, fds.out)) ||
|
|
(ret = get_fd_set(n, exp, fds.ex)))
|
|
goto out;
|
|
zero_fd_set(n, fds.res_in);
|
|
zero_fd_set(n, fds.res_out);
|
|
zero_fd_set(n, fds.res_ex);
|
|
|
|
ret = do_select(n, &fds, end_time);
|
|
|
|
if (ret < 0)
|
|
goto out;
|
|
if (!ret) {
|
|
ret = -ERESTARTNOHAND;
|
|
if (signal_pending(current))
|
|
goto out;
|
|
ret = 0;
|
|
}
|
|
|
|
if (set_fd_set(n, inp, fds.res_in) ||
|
|
set_fd_set(n, outp, fds.res_out) ||
|
|
set_fd_set(n, exp, fds.res_ex))
|
|
ret = -EFAULT;
|
|
|
|
out:
|
|
if (bits != stack_fds)
|
|
kfree(bits);
|
|
out_nofds:
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
|
|
fd_set __user *, exp, struct timeval __user *, tvp)
|
|
{
|
|
struct timespec64 end_time, *to = NULL;
|
|
struct timeval tv;
|
|
int ret;
|
|
|
|
if (tvp) {
|
|
if (copy_from_user(&tv, tvp, sizeof(tv)))
|
|
return -EFAULT;
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to,
|
|
tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
|
|
(tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = core_sys_select(n, inp, outp, exp, to);
|
|
ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
|
|
fd_set __user *exp, struct timespec __user *tsp,
|
|
const sigset_t __user *sigmask, size_t sigsetsize)
|
|
{
|
|
sigset_t ksigmask, sigsaved;
|
|
struct timespec ts;
|
|
struct timespec64 ts64, end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (tsp) {
|
|
if (copy_from_user(&ts, tsp, sizeof(ts)))
|
|
return -EFAULT;
|
|
ts64 = timespec_to_timespec64(ts);
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to, ts64.tv_sec, ts64.tv_nsec))
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (sigmask) {
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */
|
|
if (sigsetsize != sizeof(sigset_t))
|
|
return -EINVAL;
|
|
if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
|
|
return -EFAULT;
|
|
|
|
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
|
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
|
}
|
|
|
|
ret = core_sys_select(n, inp, outp, exp, to);
|
|
ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
|
|
|
|
if (ret == -ERESTARTNOHAND) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_restore_sigmask();
|
|
}
|
|
} else if (sigmask)
|
|
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Most architectures can't handle 7-argument syscalls. So we provide a
|
|
* 6-argument version where the sixth argument is a pointer to a structure
|
|
* which has a pointer to the sigset_t itself followed by a size_t containing
|
|
* the sigset size.
|
|
*/
|
|
SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
|
|
fd_set __user *, exp, struct timespec __user *, tsp,
|
|
void __user *, sig)
|
|
{
|
|
size_t sigsetsize = 0;
|
|
sigset_t __user *up = NULL;
|
|
|
|
if (sig) {
|
|
if (!access_ok(VERIFY_READ, sig, sizeof(void *)+sizeof(size_t))
|
|
|| __get_user(up, (sigset_t __user * __user *)sig)
|
|
|| __get_user(sigsetsize,
|
|
(size_t __user *)(sig+sizeof(void *))))
|
|
return -EFAULT;
|
|
}
|
|
|
|
return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize);
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_OLD_SELECT
|
|
struct sel_arg_struct {
|
|
unsigned long n;
|
|
fd_set __user *inp, *outp, *exp;
|
|
struct timeval __user *tvp;
|
|
};
|
|
|
|
SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
|
|
{
|
|
struct sel_arg_struct a;
|
|
|
|
if (copy_from_user(&a, arg, sizeof(a)))
|
|
return -EFAULT;
|
|
return sys_select(a.n, a.inp, a.outp, a.exp, a.tvp);
|
|
}
|
|
#endif
|
|
|
|
struct poll_list {
|
|
struct poll_list *next;
|
|
int len;
|
|
struct pollfd entries[0];
|
|
};
|
|
|
|
#define POLLFD_PER_PAGE ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
|
|
|
|
/*
|
|
* Fish for pollable events on the pollfd->fd file descriptor. We're only
|
|
* interested in events matching the pollfd->events mask, and the result
|
|
* matching that mask is both recorded in pollfd->revents and returned. The
|
|
* pwait poll_table will be used by the fd-provided poll handler for waiting,
|
|
* if pwait->_qproc is non-NULL.
|
|
*/
|
|
static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait,
|
|
bool *can_busy_poll,
|
|
unsigned int busy_flag)
|
|
{
|
|
unsigned int mask;
|
|
int fd;
|
|
|
|
mask = 0;
|
|
fd = pollfd->fd;
|
|
if (fd >= 0) {
|
|
struct fd f = fdget(fd);
|
|
mask = POLLNVAL;
|
|
if (f.file) {
|
|
mask = DEFAULT_POLLMASK;
|
|
if (f.file->f_op->poll) {
|
|
pwait->_key = pollfd->events|POLLERR|POLLHUP;
|
|
pwait->_key |= busy_flag;
|
|
mask = f.file->f_op->poll(f.file, pwait);
|
|
if (mask & busy_flag)
|
|
*can_busy_poll = true;
|
|
}
|
|
/* Mask out unneeded events. */
|
|
mask &= pollfd->events | POLLERR | POLLHUP;
|
|
fdput(f);
|
|
}
|
|
}
|
|
pollfd->revents = mask;
|
|
|
|
return mask;
|
|
}
|
|
|
|
static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
|
|
struct timespec64 *end_time)
|
|
{
|
|
poll_table* pt = &wait->pt;
|
|
ktime_t expire, *to = NULL;
|
|
int timed_out = 0, count = 0;
|
|
u64 slack = 0;
|
|
unsigned int busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
|
|
unsigned long busy_end = 0;
|
|
|
|
/* Optimise the no-wait case */
|
|
if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
|
|
pt->_qproc = NULL;
|
|
timed_out = 1;
|
|
}
|
|
|
|
if (end_time && !timed_out)
|
|
slack = select_estimate_accuracy(end_time);
|
|
|
|
for (;;) {
|
|
struct poll_list *walk;
|
|
bool can_busy_loop = false;
|
|
|
|
for (walk = list; walk != NULL; walk = walk->next) {
|
|
struct pollfd * pfd, * pfd_end;
|
|
|
|
pfd = walk->entries;
|
|
pfd_end = pfd + walk->len;
|
|
for (; pfd != pfd_end; pfd++) {
|
|
/*
|
|
* Fish for events. If we found one, record it
|
|
* and kill poll_table->_qproc, so we don't
|
|
* needlessly register any other waiters after
|
|
* this. They'll get immediately deregistered
|
|
* when we break out and return.
|
|
*/
|
|
if (do_pollfd(pfd, pt, &can_busy_loop,
|
|
busy_flag)) {
|
|
count++;
|
|
pt->_qproc = NULL;
|
|
/* found something, stop busy polling */
|
|
busy_flag = 0;
|
|
can_busy_loop = false;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* All waiters have already been registered, so don't provide
|
|
* a poll_table->_qproc to them on the next loop iteration.
|
|
*/
|
|
pt->_qproc = NULL;
|
|
if (!count) {
|
|
count = wait->error;
|
|
if (signal_pending(current))
|
|
count = -EINTR;
|
|
}
|
|
if (count || timed_out)
|
|
break;
|
|
|
|
/* only if found POLL_BUSY_LOOP sockets && not out of time */
|
|
if (can_busy_loop && !need_resched()) {
|
|
if (!busy_end) {
|
|
busy_end = busy_loop_end_time();
|
|
continue;
|
|
}
|
|
if (!busy_loop_timeout(busy_end))
|
|
continue;
|
|
}
|
|
busy_flag = 0;
|
|
|
|
/*
|
|
* If this is the first loop and we have a timeout
|
|
* given, then we convert to ktime_t and set the to
|
|
* pointer to the expiry value.
|
|
*/
|
|
if (end_time && !to) {
|
|
expire = timespec64_to_ktime(*end_time);
|
|
to = &expire;
|
|
}
|
|
|
|
if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
|
|
timed_out = 1;
|
|
}
|
|
return count;
|
|
}
|
|
|
|
#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
|
|
sizeof(struct pollfd))
|
|
|
|
int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
|
|
struct timespec64 *end_time)
|
|
{
|
|
struct poll_wqueues table;
|
|
int err = -EFAULT, fdcount, len, size;
|
|
/* Allocate small arguments on the stack to save memory and be
|
|
faster - use long to make sure the buffer is aligned properly
|
|
on 64 bit archs to avoid unaligned access */
|
|
long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
|
|
struct poll_list *const head = (struct poll_list *)stack_pps;
|
|
struct poll_list *walk = head;
|
|
unsigned long todo = nfds;
|
|
|
|
if (nfds > rlimit(RLIMIT_NOFILE))
|
|
return -EINVAL;
|
|
|
|
len = min_t(unsigned int, nfds, N_STACK_PPS);
|
|
for (;;) {
|
|
walk->next = NULL;
|
|
walk->len = len;
|
|
if (!len)
|
|
break;
|
|
|
|
if (copy_from_user(walk->entries, ufds + nfds-todo,
|
|
sizeof(struct pollfd) * walk->len))
|
|
goto out_fds;
|
|
|
|
todo -= walk->len;
|
|
if (!todo)
|
|
break;
|
|
|
|
len = min(todo, POLLFD_PER_PAGE);
|
|
size = sizeof(struct poll_list) + sizeof(struct pollfd) * len;
|
|
walk = walk->next = kmalloc(size, GFP_KERNEL);
|
|
if (!walk) {
|
|
err = -ENOMEM;
|
|
goto out_fds;
|
|
}
|
|
}
|
|
|
|
poll_initwait(&table);
|
|
fdcount = do_poll(head, &table, end_time);
|
|
poll_freewait(&table);
|
|
|
|
for (walk = head; walk; walk = walk->next) {
|
|
struct pollfd *fds = walk->entries;
|
|
int j;
|
|
|
|
for (j = 0; j < walk->len; j++, ufds++)
|
|
if (__put_user(fds[j].revents, &ufds->revents))
|
|
goto out_fds;
|
|
}
|
|
|
|
err = fdcount;
|
|
out_fds:
|
|
walk = head->next;
|
|
while (walk) {
|
|
struct poll_list *pos = walk;
|
|
walk = walk->next;
|
|
kfree(pos);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static long do_restart_poll(struct restart_block *restart_block)
|
|
{
|
|
struct pollfd __user *ufds = restart_block->poll.ufds;
|
|
int nfds = restart_block->poll.nfds;
|
|
struct timespec64 *to = NULL, end_time;
|
|
int ret;
|
|
|
|
if (restart_block->poll.has_timeout) {
|
|
end_time.tv_sec = restart_block->poll.tv_sec;
|
|
end_time.tv_nsec = restart_block->poll.tv_nsec;
|
|
to = &end_time;
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
if (ret == -EINTR) {
|
|
restart_block->fn = do_restart_poll;
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
|
|
int, timeout_msecs)
|
|
{
|
|
struct timespec64 end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (timeout_msecs >= 0) {
|
|
to = &end_time;
|
|
poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
|
|
NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
if (ret == -EINTR) {
|
|
struct restart_block *restart_block;
|
|
|
|
restart_block = ¤t->restart_block;
|
|
restart_block->fn = do_restart_poll;
|
|
restart_block->poll.ufds = ufds;
|
|
restart_block->poll.nfds = nfds;
|
|
|
|
if (timeout_msecs >= 0) {
|
|
restart_block->poll.tv_sec = end_time.tv_sec;
|
|
restart_block->poll.tv_nsec = end_time.tv_nsec;
|
|
restart_block->poll.has_timeout = 1;
|
|
} else
|
|
restart_block->poll.has_timeout = 0;
|
|
|
|
ret = -ERESTART_RESTARTBLOCK;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
|
|
struct timespec __user *, tsp, const sigset_t __user *, sigmask,
|
|
size_t, sigsetsize)
|
|
{
|
|
sigset_t ksigmask, sigsaved;
|
|
struct timespec ts;
|
|
struct timespec64 end_time, *to = NULL;
|
|
int ret;
|
|
|
|
if (tsp) {
|
|
if (copy_from_user(&ts, tsp, sizeof(ts)))
|
|
return -EFAULT;
|
|
|
|
to = &end_time;
|
|
if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (sigmask) {
|
|
/* XXX: Don't preclude handling different sized sigset_t's. */
|
|
if (sigsetsize != sizeof(sigset_t))
|
|
return -EINVAL;
|
|
if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
|
|
return -EFAULT;
|
|
|
|
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
|
|
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
|
|
}
|
|
|
|
ret = do_sys_poll(ufds, nfds, to);
|
|
|
|
/* We can restart this syscall, usually */
|
|
if (ret == -EINTR) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_restore_sigmask();
|
|
}
|
|
ret = -ERESTARTNOHAND;
|
|
} else if (sigmask)
|
|
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
|
|
|
ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);
|
|
|
|
return ret;
|
|
}
|