fs/select.c

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
__estimate_accuracy
select_estimate_accuracy
poll_initwait
free_poll_entry
poll_freewait
poll_get_entry
__pollwake
pollwake
__pollwait
poll_schedule_timeout
poll_select_set_timeout
poll_select_finish
get_fd_set
set_fd_set
zero_fd_set
max_select_fd
wait_key_set
do_select
core_sys_select
kern_select
SYSCALL_DEFINE5
do_pselect
SYSCALL_DEFINE6
SYSCALL_DEFINE6
SYSCALL_DEFINE1
do_poll
do_restart_poll
SYSCALL_DEFINE3
SYSCALL_DEFINE5
SYSCALL_DEFINE5
compat_get_fd_set
compat_set_fd_set
compat_core_sys_select
do_compat_select
COMPAT_SYSCALL_DEFINE5
COMPAT_SYSCALL_DEFINE1
do_compat_pselect
COMPAT_SYSCALL_DEFINE6
COMPAT_SYSCALL_DEFINE6
COMPAT_SYSCALL_DEFINE5
COMPAT_SYSCALL_DEFINE5
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * This file contains the procedures for the handling of select and poll
   4  *
   5  * Created for Linux based loosely upon Mathius Lattner's minix
   6  * patches by Peter MacDonald. Heavily edited by Linus.
   7  *
   8  *  4 February 1994
   9  *     COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
  10  *     flag set in its personality we do *not* modify the given timeout
  11  *     parameter to reflect time remaining.
  12  *
  13  *  24 January 2000
  14  *     Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation 
  15  *     of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
  16  */
  17 
  18 #include <linux/kernel.h>
  19 #include <linux/sched/signal.h>
  20 #include <linux/sched/rt.h>
  21 #include <linux/syscalls.h>
  22 #include <linux/export.h>
  23 #include <linux/slab.h>
  24 #include <linux/poll.h>
  25 #include <linux/personality.h> /* for STICKY_TIMEOUTS */
  26 #include <linux/file.h>
  27 #include <linux/fdtable.h>
  28 #include <linux/fs.h>
  29 #include <linux/rcupdate.h>
  30 #include <linux/hrtimer.h>
  31 #include <linux/freezer.h>
  32 #include <net/busy_poll.h>
  33 #include <linux/vmalloc.h>
  34 
  35 #include <linux/uaccess.h>
  36 
  37 
  38 /*
  39  * Estimate expected accuracy in ns from a timeval.
  40  *
  41  * After quite a bit of churning around, we've settled on
  42  * a simple thing of taking 0.1% of the timeout as the
  43  * slack, with a cap of 100 msec.
  44  * "nice" tasks get a 0.5% slack instead.
  45  *
  46  * Consider this comment an open invitation to come up with even
  47  * better solutions..
  48  */
  49 
  50 #define MAX_SLACK       (100 * NSEC_PER_MSEC)
  51 
  52 static long __estimate_accuracy(struct timespec64 *tv)
  53 {
  54         long slack;
  55         int divfactor = 1000;
  56 
  57         if (tv->tv_sec < 0)
  58                 return 0;
  59 
  60         if (task_nice(current) > 0)
  61                 divfactor = divfactor / 5;
  62 
  63         if (tv->tv_sec > MAX_SLACK / (NSEC_PER_SEC/divfactor))
  64                 return MAX_SLACK;
  65 
  66         slack = tv->tv_nsec / divfactor;
  67         slack += tv->tv_sec * (NSEC_PER_SEC/divfactor);
  68 
  69         if (slack > MAX_SLACK)
  70                 return MAX_SLACK;
  71 
  72         return slack;
  73 }
  74 
  75 u64 select_estimate_accuracy(struct timespec64 *tv)
  76 {
  77         u64 ret;
  78         struct timespec64 now;
  79 
  80         /*
  81          * Realtime tasks get a slack of 0 for obvious reasons.
  82          */
  83 
  84         if (rt_task(current))
  85                 return 0;
  86 
  87         ktime_get_ts64(&now);
  88         now = timespec64_sub(*tv, now);
  89         ret = __estimate_accuracy(&now);
  90         if (ret < current->timer_slack_ns)
  91                 return current->timer_slack_ns;
  92         return ret;
  93 }
  94 
  95 
  96 
  97 struct poll_table_page {
  98         struct poll_table_page * next;
  99         struct poll_table_entry * entry;
 100         struct poll_table_entry entries[0];
 101 };
 102 
 103 #define POLL_TABLE_FULL(table) \
 104         ((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
 105 
 106 /*
 107  * Ok, Peter made a complicated, but straightforward multiple_wait() function.
 108  * I have rewritten this, taking some shortcuts: This code may not be easy to
 109  * follow, but it should be free of race-conditions, and it's practical. If you
 110  * understand what I'm doing here, then you understand how the linux
 111  * sleep/wakeup mechanism works.
 112  *
 113  * Two very simple procedures, poll_wait() and poll_freewait() make all the
 114  * work.  poll_wait() is an inline-function defined in <linux/poll.h>,
 115  * as all select/poll functions have to call it to add an entry to the
 116  * poll table.
 117  */
 118 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
 119                        poll_table *p);
 120 
 121 void poll_initwait(struct poll_wqueues *pwq)
 122 {
 123         init_poll_funcptr(&pwq->pt, __pollwait);
 124         pwq->polling_task = current;
 125         pwq->triggered = 0;
 126         pwq->error = 0;
 127         pwq->table = NULL;
 128         pwq->inline_index = 0;
 129 }
 130 EXPORT_SYMBOL(poll_initwait);
 131 
 132 static void free_poll_entry(struct poll_table_entry *entry)
 133 {
 134         remove_wait_queue(entry->wait_address, &entry->wait);
 135         fput(entry->filp);
 136 }
 137 
 138 void poll_freewait(struct poll_wqueues *pwq)
 139 {
 140         struct poll_table_page * p = pwq->table;
 141         int i;
 142         for (i = 0; i < pwq->inline_index; i++)
 143                 free_poll_entry(pwq->inline_entries + i);
 144         while (p) {
 145                 struct poll_table_entry * entry;
 146                 struct poll_table_page *old;
 147 
 148                 entry = p->entry;
 149                 do {
 150                         entry--;
 151                         free_poll_entry(entry);
 152                 } while (entry > p->entries);
 153                 old = p;
 154                 p = p->next;
 155                 free_page((unsigned long) old);
 156         }
 157 }
 158 EXPORT_SYMBOL(poll_freewait);
 159 
 160 static struct poll_table_entry *poll_get_entry(struct poll_wqueues *p)
 161 {
 162         struct poll_table_page *table = p->table;
 163 
 164         if (p->inline_index < N_INLINE_POLL_ENTRIES)
 165                 return p->inline_entries + p->inline_index++;
 166 
 167         if (!table || POLL_TABLE_FULL(table)) {
 168                 struct poll_table_page *new_table;
 169 
 170                 new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
 171                 if (!new_table) {
 172                         p->error = -ENOMEM;
 173                         return NULL;
 174                 }
 175                 new_table->entry = new_table->entries;
 176                 new_table->next = table;
 177                 p->table = new_table;
 178                 table = new_table;
 179         }
 180 
 181         return table->entry++;
 182 }
 183 
 184 static int __pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 185 {
 186         struct poll_wqueues *pwq = wait->private;
 187         DECLARE_WAITQUEUE(dummy_wait, pwq->polling_task);
 188 
 189         /*
 190          * Although this function is called under waitqueue lock, LOCK
 191          * doesn't imply write barrier and the users expect write
 192          * barrier semantics on wakeup functions.  The following
 193          * smp_wmb() is equivalent to smp_wmb() in try_to_wake_up()
 194          * and is paired with smp_store_mb() in poll_schedule_timeout.
 195          */
 196         smp_wmb();
 197         pwq->triggered = 1;
 198 
 199         /*
 200          * Perform the default wake up operation using a dummy
 201          * waitqueue.
 202          *
 203          * TODO: This is hacky but there currently is no interface to
 204          * pass in @sync.  @sync is scheduled to be removed and once
 205          * that happens, wake_up_process() can be used directly.
 206          */
 207         return default_wake_function(&dummy_wait, mode, sync, key);
 208 }
 209 
 210 static int pollwake(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 211 {
 212         struct poll_table_entry *entry;
 213 
 214         entry = container_of(wait, struct poll_table_entry, wait);
 215         if (key && !(key_to_poll(key) & entry->key))
 216                 return 0;
 217         return __pollwake(wait, mode, sync, key);
 218 }
 219 
 220 /* Add a new entry */
 221 static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
 222                                 poll_table *p)
 223 {
 224         struct poll_wqueues *pwq = container_of(p, struct poll_wqueues, pt);
 225         struct poll_table_entry *entry = poll_get_entry(pwq);
 226         if (!entry)
 227                 return;
 228         entry->filp = get_file(filp);
 229         entry->wait_address = wait_address;
 230         entry->key = p->_key;
 231         init_waitqueue_func_entry(&entry->wait, pollwake);
 232         entry->wait.private = pwq;
 233         add_wait_queue(wait_address, &entry->wait);
 234 }
 235 
 236 static int poll_schedule_timeout(struct poll_wqueues *pwq, int state,
 237                           ktime_t *expires, unsigned long slack)
 238 {
 239         int rc = -EINTR;
 240 
 241         set_current_state(state);
 242         if (!pwq->triggered)
 243                 rc = schedule_hrtimeout_range(expires, slack, HRTIMER_MODE_ABS);
 244         __set_current_state(TASK_RUNNING);
 245 
 246         /*
 247          * Prepare for the next iteration.
 248          *
 249          * The following smp_store_mb() serves two purposes.  First, it's
 250          * the counterpart rmb of the wmb in pollwake() such that data
 251          * written before wake up is always visible after wake up.
 252          * Second, the full barrier guarantees that triggered clearing
 253          * doesn't pass event check of the next iteration.  Note that
 254          * this problem doesn't exist for the first iteration as
 255          * add_wait_queue() has full barrier semantics.
 256          */
 257         smp_store_mb(pwq->triggered, 0);
 258 
 259         return rc;
 260 }
 261 
 262 /**
 263  * poll_select_set_timeout - helper function to setup the timeout value
 264  * @to:         pointer to timespec64 variable for the final timeout
 265  * @sec:        seconds (from user space)
 266  * @nsec:       nanoseconds (from user space)
 267  *
 268  * Note, we do not use a timespec for the user space value here, That
 269  * way we can use the function for timeval and compat interfaces as well.
 270  *
 271  * Returns -EINVAL if sec/nsec are not normalized. Otherwise 0.
 272  */
 273 int poll_select_set_timeout(struct timespec64 *to, time64_t sec, long nsec)
 274 {
 275         struct timespec64 ts = {.tv_sec = sec, .tv_nsec = nsec};
 276 
 277         if (!timespec64_valid(&ts))
 278                 return -EINVAL;
 279 
 280         /* Optimize for the zero timeout value here */
 281         if (!sec && !nsec) {
 282                 to->tv_sec = to->tv_nsec = 0;
 283         } else {
 284                 ktime_get_ts64(to);
 285                 *to = timespec64_add_safe(*to, ts);
 286         }
 287         return 0;
 288 }
 289 
 290 enum poll_time_type {
 291         PT_TIMEVAL = 0,
 292         PT_OLD_TIMEVAL = 1,
 293         PT_TIMESPEC = 2,
 294         PT_OLD_TIMESPEC = 3,
 295 };
 296 
 297 static int poll_select_finish(struct timespec64 *end_time,
 298                               void __user *p,
 299                               enum poll_time_type pt_type, int ret)
 300 {
 301         struct timespec64 rts;
 302 
 303         restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
 304 
 305         if (!p)
 306                 return ret;
 307 
 308         if (current->personality & STICKY_TIMEOUTS)
 309                 goto sticky;
 310 
 311         /* No update for zero timeout */
 312         if (!end_time->tv_sec && !end_time->tv_nsec)
 313                 return ret;
 314 
 315         ktime_get_ts64(&rts);
 316         rts = timespec64_sub(*end_time, rts);
 317         if (rts.tv_sec < 0)
 318                 rts.tv_sec = rts.tv_nsec = 0;
 319 
 320 
 321         switch (pt_type) {
 322         case PT_TIMEVAL:
 323                 {
 324                         struct timeval rtv;
 325 
 326                         if (sizeof(rtv) > sizeof(rtv.tv_sec) + sizeof(rtv.tv_usec))
 327                                 memset(&rtv, 0, sizeof(rtv));
 328                         rtv.tv_sec = rts.tv_sec;
 329                         rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
 330                         if (!copy_to_user(p, &rtv, sizeof(rtv)))
 331                                 return ret;
 332                 }
 333                 break;
 334         case PT_OLD_TIMEVAL:
 335                 {
 336                         struct old_timeval32 rtv;
 337 
 338                         rtv.tv_sec = rts.tv_sec;
 339                         rtv.tv_usec = rts.tv_nsec / NSEC_PER_USEC;
 340                         if (!copy_to_user(p, &rtv, sizeof(rtv)))
 341                                 return ret;
 342                 }
 343                 break;
 344         case PT_TIMESPEC:
 345                 if (!put_timespec64(&rts, p))
 346                         return ret;
 347                 break;
 348         case PT_OLD_TIMESPEC:
 349                 if (!put_old_timespec32(&rts, p))
 350                         return ret;
 351                 break;
 352         default:
 353                 BUG();
 354         }
 355         /*
 356          * If an application puts its timeval in read-only memory, we
 357          * don't want the Linux-specific update to the timeval to
 358          * cause a fault after the select has completed
 359          * successfully. However, because we're not updating the
 360          * timeval, we can't restart the system call.
 361          */
 362 
 363 sticky:
 364         if (ret == -ERESTARTNOHAND)
 365                 ret = -EINTR;
 366         return ret;
 367 }
 368 
 369 /*
 370  * Scalable version of the fd_set.
 371  */
 372 
 373 typedef struct {
 374         unsigned long *in, *out, *ex;
 375         unsigned long *res_in, *res_out, *res_ex;
 376 } fd_set_bits;
 377 
 378 /*
 379  * How many longwords for "nr" bits?
 380  */
 381 #define FDS_BITPERLONG  (8*sizeof(long))
 382 #define FDS_LONGS(nr)   (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
 383 #define FDS_BYTES(nr)   (FDS_LONGS(nr)*sizeof(long))
 384 
 385 /*
 386  * Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
 387  */
 388 static inline
 389 int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 390 {
 391         nr = FDS_BYTES(nr);
 392         if (ufdset)
 393                 return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
 394 
 395         memset(fdset, 0, nr);
 396         return 0;
 397 }
 398 
 399 static inline unsigned long __must_check
 400 set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
 401 {
 402         if (ufdset)
 403                 return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
 404         return 0;
 405 }
 406 
 407 static inline
 408 void zero_fd_set(unsigned long nr, unsigned long *fdset)
 409 {
 410         memset(fdset, 0, FDS_BYTES(nr));
 411 }
 412 
 413 #define FDS_IN(fds, n)          (fds->in + n)
 414 #define FDS_OUT(fds, n)         (fds->out + n)
 415 #define FDS_EX(fds, n)          (fds->ex + n)
 416 
 417 #define BITS(fds, n)    (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
 418 
 419 static int max_select_fd(unsigned long n, fd_set_bits *fds)
 420 {
 421         unsigned long *open_fds;
 422         unsigned long set;
 423         int max;
 424         struct fdtable *fdt;
 425 
 426         /* handle last in-complete long-word first */
 427         set = ~(~0UL << (n & (BITS_PER_LONG-1)));
 428         n /= BITS_PER_LONG;
 429         fdt = files_fdtable(current->files);
 430         open_fds = fdt->open_fds + n;
 431         max = 0;
 432         if (set) {
 433                 set &= BITS(fds, n);
 434                 if (set) {
 435                         if (!(set & ~*open_fds))
 436                                 goto get_max;
 437                         return -EBADF;
 438                 }
 439         }
 440         while (n) {
 441                 open_fds--;
 442                 n--;
 443                 set = BITS(fds, n);
 444                 if (!set)
 445                         continue;
 446                 if (set & ~*open_fds)
 447                         return -EBADF;
 448                 if (max)
 449                         continue;
 450 get_max:
 451                 do {
 452                         max++;
 453                         set >>= 1;
 454                 } while (set);
 455                 max += n * BITS_PER_LONG;
 456         }
 457 
 458         return max;
 459 }
 460 
 461 #define POLLIN_SET (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR)
 462 #define POLLOUT_SET (EPOLLWRBAND | EPOLLWRNORM | EPOLLOUT | EPOLLERR)
 463 #define POLLEX_SET (EPOLLPRI)
 464 
 465 static inline void wait_key_set(poll_table *wait, unsigned long in,
 466                                 unsigned long out, unsigned long bit,
 467                                 __poll_t ll_flag)
 468 {
 469         wait->_key = POLLEX_SET | ll_flag;
 470         if (in & bit)
 471                 wait->_key |= POLLIN_SET;
 472         if (out & bit)
 473                 wait->_key |= POLLOUT_SET;
 474 }
 475 
 476 static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time)
 477 {
 478         ktime_t expire, *to = NULL;
 479         struct poll_wqueues table;
 480         poll_table *wait;
 481         int retval, i, timed_out = 0;
 482         u64 slack = 0;
 483         __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
 484         unsigned long busy_start = 0;
 485 
 486         rcu_read_lock();
 487         retval = max_select_fd(n, fds);
 488         rcu_read_unlock();
 489 
 490         if (retval < 0)
 491                 return retval;
 492         n = retval;
 493 
 494         poll_initwait(&table);
 495         wait = &table.pt;
 496         if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
 497                 wait->_qproc = NULL;
 498                 timed_out = 1;
 499         }
 500 
 501         if (end_time && !timed_out)
 502                 slack = select_estimate_accuracy(end_time);
 503 
 504         retval = 0;
 505         for (;;) {
 506                 unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
 507                 bool can_busy_loop = false;
 508 
 509                 inp = fds->in; outp = fds->out; exp = fds->ex;
 510                 rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
 511 
 512                 for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
 513                         unsigned long in, out, ex, all_bits, bit = 1, j;
 514                         unsigned long res_in = 0, res_out = 0, res_ex = 0;
 515                         __poll_t mask;
 516 
 517                         in = *inp++; out = *outp++; ex = *exp++;
 518                         all_bits = in | out | ex;
 519                         if (all_bits == 0) {
 520                                 i += BITS_PER_LONG;
 521                                 continue;
 522                         }
 523 
 524                         for (j = 0; j < BITS_PER_LONG; ++j, ++i, bit <<= 1) {
 525                                 struct fd f;
 526                                 if (i >= n)
 527                                         break;
 528                                 if (!(bit & all_bits))
 529                                         continue;
 530                                 f = fdget(i);
 531                                 if (f.file) {
 532                                         wait_key_set(wait, in, out, bit,
 533                                                      busy_flag);
 534                                         mask = vfs_poll(f.file, wait);
 535 
 536                                         fdput(f);
 537                                         if ((mask & POLLIN_SET) && (in & bit)) {
 538                                                 res_in |= bit;
 539                                                 retval++;
 540                                                 wait->_qproc = NULL;
 541                                         }
 542                                         if ((mask & POLLOUT_SET) && (out & bit)) {
 543                                                 res_out |= bit;
 544                                                 retval++;
 545                                                 wait->_qproc = NULL;
 546                                         }
 547                                         if ((mask & POLLEX_SET) && (ex & bit)) {
 548                                                 res_ex |= bit;
 549                                                 retval++;
 550                                                 wait->_qproc = NULL;
 551                                         }
 552                                         /* got something, stop busy polling */
 553                                         if (retval) {
 554                                                 can_busy_loop = false;
 555                                                 busy_flag = 0;
 556 
 557                                         /*
 558                                          * only remember a returned
 559                                          * POLL_BUSY_LOOP if we asked for it
 560                                          */
 561                                         } else if (busy_flag & mask)
 562                                                 can_busy_loop = true;
 563 
 564                                 }
 565                         }
 566                         if (res_in)
 567                                 *rinp = res_in;
 568                         if (res_out)
 569                                 *routp = res_out;
 570                         if (res_ex)
 571                                 *rexp = res_ex;
 572                         cond_resched();
 573                 }
 574                 wait->_qproc = NULL;
 575                 if (retval || timed_out || signal_pending(current))
 576                         break;
 577                 if (table.error) {
 578                         retval = table.error;
 579                         break;
 580                 }
 581 
 582                 /* only if found POLL_BUSY_LOOP sockets && not out of time */
 583                 if (can_busy_loop && !need_resched()) {
 584                         if (!busy_start) {
 585                                 busy_start = busy_loop_current_time();
 586                                 continue;
 587                         }
 588                         if (!busy_loop_timeout(busy_start))
 589                                 continue;
 590                 }
 591                 busy_flag = 0;
 592 
 593                 /*
 594                  * If this is the first loop and we have a timeout
 595                  * given, then we convert to ktime_t and set the to
 596                  * pointer to the expiry value.
 597                  */
 598                 if (end_time && !to) {
 599                         expire = timespec64_to_ktime(*end_time);
 600                         to = &expire;
 601                 }
 602 
 603                 if (!poll_schedule_timeout(&table, TASK_INTERRUPTIBLE,
 604                                            to, slack))
 605                         timed_out = 1;
 606         }
 607 
 608         poll_freewait(&table);
 609 
 610         return retval;
 611 }
 612 
 613 /*
 614  * We can actually return ERESTARTSYS instead of EINTR, but I'd
 615  * like to be certain this leads to no problems. So I return
 616  * EINTR just for safety.
 617  *
 618  * Update: ERESTARTSYS breaks at least the xview clock binary, so
 619  * I'm trying ERESTARTNOHAND which restart only when you want to.
 620  */
 621 int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
 622                            fd_set __user *exp, struct timespec64 *end_time)
 623 {
 624         fd_set_bits fds;
 625         void *bits;
 626         int ret, max_fds;
 627         size_t size, alloc_size;
 628         struct fdtable *fdt;
 629         /* Allocate small arguments on the stack to save memory and be faster */
 630         long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
 631 
 632         ret = -EINVAL;
 633         if (n < 0)
 634                 goto out_nofds;
 635 
 636         /* max_fds can increase, so grab it once to avoid race */
 637         rcu_read_lock();
 638         fdt = files_fdtable(current->files);
 639         max_fds = fdt->max_fds;
 640         rcu_read_unlock();
 641         if (n > max_fds)
 642                 n = max_fds;
 643 
 644         /*
 645          * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
 646          * since we used fdset we need to allocate memory in units of
 647          * long-words. 
 648          */
 649         size = FDS_BYTES(n);
 650         bits = stack_fds;
 651         if (size > sizeof(stack_fds) / 6) {
 652                 /* Not enough space in on-stack array; must use kmalloc */
 653                 ret = -ENOMEM;
 654                 if (size > (SIZE_MAX / 6))
 655                         goto out_nofds;
 656 
 657                 alloc_size = 6 * size;
 658                 bits = kvmalloc(alloc_size, GFP_KERNEL);
 659                 if (!bits)
 660                         goto out_nofds;
 661         }
 662         fds.in      = bits;
 663         fds.out     = bits +   size;
 664         fds.ex      = bits + 2*size;
 665         fds.res_in  = bits + 3*size;
 666         fds.res_out = bits + 4*size;
 667         fds.res_ex  = bits + 5*size;
 668 
 669         if ((ret = get_fd_set(n, inp, fds.in)) ||
 670             (ret = get_fd_set(n, outp, fds.out)) ||
 671             (ret = get_fd_set(n, exp, fds.ex)))
 672                 goto out;
 673         zero_fd_set(n, fds.res_in);
 674         zero_fd_set(n, fds.res_out);
 675         zero_fd_set(n, fds.res_ex);
 676 
 677         ret = do_select(n, &fds, end_time);
 678 
 679         if (ret < 0)
 680                 goto out;
 681         if (!ret) {
 682                 ret = -ERESTARTNOHAND;
 683                 if (signal_pending(current))
 684                         goto out;
 685                 ret = 0;
 686         }
 687 
 688         if (set_fd_set(n, inp, fds.res_in) ||
 689             set_fd_set(n, outp, fds.res_out) ||
 690             set_fd_set(n, exp, fds.res_ex))
 691                 ret = -EFAULT;
 692 
 693 out:
 694         if (bits != stack_fds)
 695                 kvfree(bits);
 696 out_nofds:
 697         return ret;
 698 }
 699 
 700 static int kern_select(int n, fd_set __user *inp, fd_set __user *outp,
 701                        fd_set __user *exp, struct timeval __user *tvp)
 702 {
 703         struct timespec64 end_time, *to = NULL;
 704         struct timeval tv;
 705         int ret;
 706 
 707         if (tvp) {
 708                 if (copy_from_user(&tv, tvp, sizeof(tv)))
 709                         return -EFAULT;
 710 
 711                 to = &end_time;
 712                 if (poll_select_set_timeout(to,
 713                                 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
 714                                 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
 715                         return -EINVAL;
 716         }
 717 
 718         ret = core_sys_select(n, inp, outp, exp, to);
 719         return poll_select_finish(&end_time, tvp, PT_TIMEVAL, ret);
 720 }
 721 
 722 SYSCALL_DEFINE5(select, int, n, fd_set __user *, inp, fd_set __user *, outp,
 723                 fd_set __user *, exp, struct timeval __user *, tvp)
 724 {
 725         return kern_select(n, inp, outp, exp, tvp);
 726 }
 727 
 728 static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
 729                        fd_set __user *exp, void __user *tsp,
 730                        const sigset_t __user *sigmask, size_t sigsetsize,
 731                        enum poll_time_type type)
 732 {
 733         struct timespec64 ts, end_time, *to = NULL;
 734         int ret;
 735 
 736         if (tsp) {
 737                 switch (type) {
 738                 case PT_TIMESPEC:
 739                         if (get_timespec64(&ts, tsp))
 740                                 return -EFAULT;
 741                         break;
 742                 case PT_OLD_TIMESPEC:
 743                         if (get_old_timespec32(&ts, tsp))
 744                                 return -EFAULT;
 745                         break;
 746                 default:
 747                         BUG();
 748                 }
 749 
 750                 to = &end_time;
 751                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
 752                         return -EINVAL;
 753         }
 754 
 755         ret = set_user_sigmask(sigmask, sigsetsize);
 756         if (ret)
 757                 return ret;
 758 
 759         ret = core_sys_select(n, inp, outp, exp, to);
 760         return poll_select_finish(&end_time, tsp, type, ret);
 761 }
 762 
 763 /*
 764  * Most architectures can't handle 7-argument syscalls. So we provide a
 765  * 6-argument version where the sixth argument is a pointer to a structure
 766  * which has a pointer to the sigset_t itself followed by a size_t containing
 767  * the sigset size.
 768  */
 769 SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
 770                 fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
 771                 void __user *, sig)
 772 {
 773         size_t sigsetsize = 0;
 774         sigset_t __user *up = NULL;
 775 
 776         if (sig) {
 777                 if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
 778                     || __get_user(up, (sigset_t __user * __user *)sig)
 779                     || __get_user(sigsetsize,
 780                                 (size_t __user *)(sig+sizeof(void *))))
 781                         return -EFAULT;
 782         }
 783 
 784         return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_TIMESPEC);
 785 }
 786 
 787 #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
 788 
 789 SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *, outp,
 790                 fd_set __user *, exp, struct old_timespec32 __user *, tsp,
 791                 void __user *, sig)
 792 {
 793         size_t sigsetsize = 0;
 794         sigset_t __user *up = NULL;
 795 
 796         if (sig) {
 797                 if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
 798                     || __get_user(up, (sigset_t __user * __user *)sig)
 799                     || __get_user(sigsetsize,
 800                                 (size_t __user *)(sig+sizeof(void *))))
 801                         return -EFAULT;
 802         }
 803 
 804         return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_OLD_TIMESPEC);
 805 }
 806 
 807 #endif
 808 
 809 #ifdef __ARCH_WANT_SYS_OLD_SELECT
 810 struct sel_arg_struct {
 811         unsigned long n;
 812         fd_set __user *inp, *outp, *exp;
 813         struct timeval __user *tvp;
 814 };
 815 
 816 SYSCALL_DEFINE1(old_select, struct sel_arg_struct __user *, arg)
 817 {
 818         struct sel_arg_struct a;
 819 
 820         if (copy_from_user(&a, arg, sizeof(a)))
 821                 return -EFAULT;
 822         return kern_select(a.n, a.inp, a.outp, a.exp, a.tvp);
 823 }
 824 #endif
 825 
 826 struct poll_list {
 827         struct poll_list *next;
 828         int len;
 829         struct pollfd entries[0];
 830 };
 831 
 832 #define POLLFD_PER_PAGE  ((PAGE_SIZE-sizeof(struct poll_list)) / sizeof(struct pollfd))
 833 
 834 /*
 835  * Fish for pollable events on the pollfd->fd file descriptor. We're only
 836  * interested in events matching the pollfd->events mask, and the result
 837  * matching that mask is both recorded in pollfd->revents and returned. The
 838  * pwait poll_table will be used by the fd-provided poll handler for waiting,
 839  * if pwait->_qproc is non-NULL.
 840  */
 841 static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait,
 842                                      bool *can_busy_poll,
 843                                      __poll_t busy_flag)
 844 {
 845         int fd = pollfd->fd;
 846         __poll_t mask = 0, filter;
 847         struct fd f;
 848 
 849         if (fd < 0)
 850                 goto out;
 851         mask = EPOLLNVAL;
 852         f = fdget(fd);
 853         if (!f.file)
 854                 goto out;
 855 
 856         /* userland u16 ->events contains POLL... bitmap */
 857         filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
 858         pwait->_key = filter | busy_flag;
 859         mask = vfs_poll(f.file, pwait);
 860         if (mask & busy_flag)
 861                 *can_busy_poll = true;
 862         mask &= filter;         /* Mask out unneeded events. */
 863         fdput(f);
 864 
 865 out:
 866         /* ... and so does ->revents */
 867         pollfd->revents = mangle_poll(mask);
 868         return mask;
 869 }
 870 
 871 static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
 872                    struct timespec64 *end_time)
 873 {
 874         poll_table* pt = &wait->pt;
 875         ktime_t expire, *to = NULL;
 876         int timed_out = 0, count = 0;
 877         u64 slack = 0;
 878         __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
 879         unsigned long busy_start = 0;
 880 
 881         /* Optimise the no-wait case */
 882         if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
 883                 pt->_qproc = NULL;
 884                 timed_out = 1;
 885         }
 886 
 887         if (end_time && !timed_out)
 888                 slack = select_estimate_accuracy(end_time);
 889 
 890         for (;;) {
 891                 struct poll_list *walk;
 892                 bool can_busy_loop = false;
 893 
 894                 for (walk = list; walk != NULL; walk = walk->next) {
 895                         struct pollfd * pfd, * pfd_end;
 896 
 897                         pfd = walk->entries;
 898                         pfd_end = pfd + walk->len;
 899                         for (; pfd != pfd_end; pfd++) {
 900                                 /*
 901                                  * Fish for events. If we found one, record it
 902                                  * and kill poll_table->_qproc, so we don't
 903                                  * needlessly register any other waiters after
 904                                  * this. They'll get immediately deregistered
 905                                  * when we break out and return.
 906                                  */
 907                                 if (do_pollfd(pfd, pt, &can_busy_loop,
 908                                               busy_flag)) {
 909                                         count++;
 910                                         pt->_qproc = NULL;
 911                                         /* found something, stop busy polling */
 912                                         busy_flag = 0;
 913                                         can_busy_loop = false;
 914                                 }
 915                         }
 916                 }
 917                 /*
 918                  * All waiters have already been registered, so don't provide
 919                  * a poll_table->_qproc to them on the next loop iteration.
 920                  */
 921                 pt->_qproc = NULL;
 922                 if (!count) {
 923                         count = wait->error;
 924                         if (signal_pending(current))
 925                                 count = -ERESTARTNOHAND;
 926                 }
 927                 if (count || timed_out)
 928                         break;
 929 
 930                 /* only if found POLL_BUSY_LOOP sockets && not out of time */
 931                 if (can_busy_loop && !need_resched()) {
 932                         if (!busy_start) {
 933                                 busy_start = busy_loop_current_time();
 934                                 continue;
 935                         }
 936                         if (!busy_loop_timeout(busy_start))
 937                                 continue;
 938                 }
 939                 busy_flag = 0;
 940 
 941                 /*
 942                  * If this is the first loop and we have a timeout
 943                  * given, then we convert to ktime_t and set the to
 944                  * pointer to the expiry value.
 945                  */
 946                 if (end_time && !to) {
 947                         expire = timespec64_to_ktime(*end_time);
 948                         to = &expire;
 949                 }
 950 
 951                 if (!poll_schedule_timeout(wait, TASK_INTERRUPTIBLE, to, slack))
 952                         timed_out = 1;
 953         }
 954         return count;
 955 }
 956 
 957 #define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list))  / \
 958                         sizeof(struct pollfd))
 959 
 960 static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
 961                 struct timespec64 *end_time)
 962 {
 963         struct poll_wqueues table;
 964         int err = -EFAULT, fdcount, len;
 965         /* Allocate small arguments on the stack to save memory and be
 966            faster - use long to make sure the buffer is aligned properly
 967            on 64 bit archs to avoid unaligned access */
 968         long stack_pps[POLL_STACK_ALLOC/sizeof(long)];
 969         struct poll_list *const head = (struct poll_list *)stack_pps;
 970         struct poll_list *walk = head;
 971         unsigned long todo = nfds;
 972 
 973         if (nfds > rlimit(RLIMIT_NOFILE))
 974                 return -EINVAL;
 975 
 976         len = min_t(unsigned int, nfds, N_STACK_PPS);
 977         for (;;) {
 978                 walk->next = NULL;
 979                 walk->len = len;
 980                 if (!len)
 981                         break;
 982 
 983                 if (copy_from_user(walk->entries, ufds + nfds-todo,
 984                                         sizeof(struct pollfd) * walk->len))
 985                         goto out_fds;
 986 
 987                 todo -= walk->len;
 988                 if (!todo)
 989                         break;
 990 
 991                 len = min(todo, POLLFD_PER_PAGE);
 992                 walk = walk->next = kmalloc(struct_size(walk, entries, len),
 993                                             GFP_KERNEL);
 994                 if (!walk) {
 995                         err = -ENOMEM;
 996                         goto out_fds;
 997                 }
 998         }
 999 
1000         poll_initwait(&table);
1001         fdcount = do_poll(head, &table, end_time);
1002         poll_freewait(&table);
1003 
1004         for (walk = head; walk; walk = walk->next) {
1005                 struct pollfd *fds = walk->entries;
1006                 int j;
1007 
1008                 for (j = 0; j < walk->len; j++, ufds++)
1009                         if (__put_user(fds[j].revents, &ufds->revents))
1010                                 goto out_fds;
1011         }
1012 
1013         err = fdcount;
1014 out_fds:
1015         walk = head->next;
1016         while (walk) {
1017                 struct poll_list *pos = walk;
1018                 walk = walk->next;
1019                 kfree(pos);
1020         }
1021 
1022         return err;
1023 }
1024 
1025 static long do_restart_poll(struct restart_block *restart_block)
1026 {
1027         struct pollfd __user *ufds = restart_block->poll.ufds;
1028         int nfds = restart_block->poll.nfds;
1029         struct timespec64 *to = NULL, end_time;
1030         int ret;
1031 
1032         if (restart_block->poll.has_timeout) {
1033                 end_time.tv_sec = restart_block->poll.tv_sec;
1034                 end_time.tv_nsec = restart_block->poll.tv_nsec;
1035                 to = &end_time;
1036         }
1037 
1038         ret = do_sys_poll(ufds, nfds, to);
1039 
1040         if (ret == -ERESTARTNOHAND) {
1041                 restart_block->fn = do_restart_poll;
1042                 ret = -ERESTART_RESTARTBLOCK;
1043         }
1044         return ret;
1045 }
1046 
1047 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
1048                 int, timeout_msecs)
1049 {
1050         struct timespec64 end_time, *to = NULL;
1051         int ret;
1052 
1053         if (timeout_msecs >= 0) {
1054                 to = &end_time;
1055                 poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
1056                         NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
1057         }
1058 
1059         ret = do_sys_poll(ufds, nfds, to);
1060 
1061         if (ret == -ERESTARTNOHAND) {
1062                 struct restart_block *restart_block;
1063 
1064                 restart_block = &current->restart_block;
1065                 restart_block->fn = do_restart_poll;
1066                 restart_block->poll.ufds = ufds;
1067                 restart_block->poll.nfds = nfds;
1068 
1069                 if (timeout_msecs >= 0) {
1070                         restart_block->poll.tv_sec = end_time.tv_sec;
1071                         restart_block->poll.tv_nsec = end_time.tv_nsec;
1072                         restart_block->poll.has_timeout = 1;
1073                 } else
1074                         restart_block->poll.has_timeout = 0;
1075 
1076                 ret = -ERESTART_RESTARTBLOCK;
1077         }
1078         return ret;
1079 }
1080 
1081 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
1082                 struct __kernel_timespec __user *, tsp, const sigset_t __user *, sigmask,
1083                 size_t, sigsetsize)
1084 {
1085         struct timespec64 ts, end_time, *to = NULL;
1086         int ret;
1087 
1088         if (tsp) {
1089                 if (get_timespec64(&ts, tsp))
1090                         return -EFAULT;
1091 
1092                 to = &end_time;
1093                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1094                         return -EINVAL;
1095         }
1096 
1097         ret = set_user_sigmask(sigmask, sigsetsize);
1098         if (ret)
1099                 return ret;
1100 
1101         ret = do_sys_poll(ufds, nfds, to);
1102         return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
1103 }
1104 
1105 #if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
1106 
1107 SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds, unsigned int, nfds,
1108                 struct old_timespec32 __user *, tsp, const sigset_t __user *, sigmask,
1109                 size_t, sigsetsize)
1110 {
1111         struct timespec64 ts, end_time, *to = NULL;
1112         int ret;
1113 
1114         if (tsp) {
1115                 if (get_old_timespec32(&ts, tsp))
1116                         return -EFAULT;
1117 
1118                 to = &end_time;
1119                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1120                         return -EINVAL;
1121         }
1122 
1123         ret = set_user_sigmask(sigmask, sigsetsize);
1124         if (ret)
1125                 return ret;
1126 
1127         ret = do_sys_poll(ufds, nfds, to);
1128         return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1129 }
1130 #endif
1131 
1132 #ifdef CONFIG_COMPAT
1133 #define __COMPAT_NFDBITS       (8 * sizeof(compat_ulong_t))
1134 
1135 /*
1136  * Ooo, nasty.  We need here to frob 32-bit unsigned longs to
1137  * 64-bit unsigned longs.
1138  */
1139 static
1140 int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1141                         unsigned long *fdset)
1142 {
1143         if (ufdset) {
1144                 return compat_get_bitmap(fdset, ufdset, nr);
1145         } else {
1146                 zero_fd_set(nr, fdset);
1147                 return 0;
1148         }
1149 }
1150 
1151 static
1152 int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
1153                       unsigned long *fdset)
1154 {
1155         if (!ufdset)
1156                 return 0;
1157         return compat_put_bitmap(ufdset, fdset, nr);
1158 }
1159 
1160 
1161 /*
1162  * This is a virtual copy of sys_select from fs/select.c and probably
1163  * should be compared to it from time to time
1164  */
1165 
1166 /*
1167  * We can actually return ERESTARTSYS instead of EINTR, but I'd
1168  * like to be certain this leads to no problems. So I return
1169  * EINTR just for safety.
1170  *
1171  * Update: ERESTARTSYS breaks at least the xview clock binary, so
1172  * I'm trying ERESTARTNOHAND which restart only when you want to.
1173  */
1174 static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
1175         compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1176         struct timespec64 *end_time)
1177 {
1178         fd_set_bits fds;
1179         void *bits;
1180         int size, max_fds, ret = -EINVAL;
1181         struct fdtable *fdt;
1182         long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
1183 
1184         if (n < 0)
1185                 goto out_nofds;
1186 
1187         /* max_fds can increase, so grab it once to avoid race */
1188         rcu_read_lock();
1189         fdt = files_fdtable(current->files);
1190         max_fds = fdt->max_fds;
1191         rcu_read_unlock();
1192         if (n > max_fds)
1193                 n = max_fds;
1194 
1195         /*
1196          * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
1197          * since we used fdset we need to allocate memory in units of
1198          * long-words.
1199          */
1200         size = FDS_BYTES(n);
1201         bits = stack_fds;
1202         if (size > sizeof(stack_fds) / 6) {
1203                 bits = kmalloc_array(6, size, GFP_KERNEL);
1204                 ret = -ENOMEM;
1205                 if (!bits)
1206                         goto out_nofds;
1207         }
1208         fds.in      = (unsigned long *)  bits;
1209         fds.out     = (unsigned long *) (bits +   size);
1210         fds.ex      = (unsigned long *) (bits + 2*size);
1211         fds.res_in  = (unsigned long *) (bits + 3*size);
1212         fds.res_out = (unsigned long *) (bits + 4*size);
1213         fds.res_ex  = (unsigned long *) (bits + 5*size);
1214 
1215         if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
1216             (ret = compat_get_fd_set(n, outp, fds.out)) ||
1217             (ret = compat_get_fd_set(n, exp, fds.ex)))
1218                 goto out;
1219         zero_fd_set(n, fds.res_in);
1220         zero_fd_set(n, fds.res_out);
1221         zero_fd_set(n, fds.res_ex);
1222 
1223         ret = do_select(n, &fds, end_time);
1224 
1225         if (ret < 0)
1226                 goto out;
1227         if (!ret) {
1228                 ret = -ERESTARTNOHAND;
1229                 if (signal_pending(current))
1230                         goto out;
1231                 ret = 0;
1232         }
1233 
1234         if (compat_set_fd_set(n, inp, fds.res_in) ||
1235             compat_set_fd_set(n, outp, fds.res_out) ||
1236             compat_set_fd_set(n, exp, fds.res_ex))
1237                 ret = -EFAULT;
1238 out:
1239         if (bits != stack_fds)
1240                 kfree(bits);
1241 out_nofds:
1242         return ret;
1243 }
1244 
1245 static int do_compat_select(int n, compat_ulong_t __user *inp,
1246         compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1247         struct old_timeval32 __user *tvp)
1248 {
1249         struct timespec64 end_time, *to = NULL;
1250         struct old_timeval32 tv;
1251         int ret;
1252 
1253         if (tvp) {
1254                 if (copy_from_user(&tv, tvp, sizeof(tv)))
1255                         return -EFAULT;
1256 
1257                 to = &end_time;
1258                 if (poll_select_set_timeout(to,
1259                                 tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
1260                                 (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
1261                         return -EINVAL;
1262         }
1263 
1264         ret = compat_core_sys_select(n, inp, outp, exp, to);
1265         return poll_select_finish(&end_time, tvp, PT_OLD_TIMEVAL, ret);
1266 }
1267 
1268 COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
1269         compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1270         struct old_timeval32 __user *, tvp)
1271 {
1272         return do_compat_select(n, inp, outp, exp, tvp);
1273 }
1274 
1275 struct compat_sel_arg_struct {
1276         compat_ulong_t n;
1277         compat_uptr_t inp;
1278         compat_uptr_t outp;
1279         compat_uptr_t exp;
1280         compat_uptr_t tvp;
1281 };
1282 
1283 COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
1284 {
1285         struct compat_sel_arg_struct a;
1286 
1287         if (copy_from_user(&a, arg, sizeof(a)))
1288                 return -EFAULT;
1289         return do_compat_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
1290                                 compat_ptr(a.exp), compat_ptr(a.tvp));
1291 }
1292 
1293 static long do_compat_pselect(int n, compat_ulong_t __user *inp,
1294         compat_ulong_t __user *outp, compat_ulong_t __user *exp,
1295         void __user *tsp, compat_sigset_t __user *sigmask,
1296         compat_size_t sigsetsize, enum poll_time_type type)
1297 {
1298         struct timespec64 ts, end_time, *to = NULL;
1299         int ret;
1300 
1301         if (tsp) {
1302                 switch (type) {
1303                 case PT_OLD_TIMESPEC:
1304                         if (get_old_timespec32(&ts, tsp))
1305                                 return -EFAULT;
1306                         break;
1307                 case PT_TIMESPEC:
1308                         if (get_timespec64(&ts, tsp))
1309                                 return -EFAULT;
1310                         break;
1311                 default:
1312                         BUG();
1313                 }
1314 
1315                 to = &end_time;
1316                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1317                         return -EINVAL;
1318         }
1319 
1320         ret = set_compat_user_sigmask(sigmask, sigsetsize);
1321         if (ret)
1322                 return ret;
1323 
1324         ret = compat_core_sys_select(n, inp, outp, exp, to);
1325         return poll_select_finish(&end_time, tsp, type, ret);
1326 }
1327 
1328 COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
1329         compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1330         struct __kernel_timespec __user *, tsp, void __user *, sig)
1331 {
1332         compat_size_t sigsetsize = 0;
1333         compat_uptr_t up = 0;
1334 
1335         if (sig) {
1336                 if (!access_ok(sig,
1337                                 sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
1338                                 __get_user(up, (compat_uptr_t __user *)sig) ||
1339                                 __get_user(sigsetsize,
1340                                 (compat_size_t __user *)(sig+sizeof(up))))
1341                         return -EFAULT;
1342         }
1343 
1344         return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
1345                                  sigsetsize, PT_TIMESPEC);
1346 }
1347 
1348 #if defined(CONFIG_COMPAT_32BIT_TIME)
1349 
1350 COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp,
1351         compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
1352         struct old_timespec32 __user *, tsp, void __user *, sig)
1353 {
1354         compat_size_t sigsetsize = 0;
1355         compat_uptr_t up = 0;
1356 
1357         if (sig) {
1358                 if (!access_ok(sig,
1359                                 sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
1360                         __get_user(up, (compat_uptr_t __user *)sig) ||
1361                         __get_user(sigsetsize,
1362                                 (compat_size_t __user *)(sig+sizeof(up))))
1363                         return -EFAULT;
1364         }
1365 
1366         return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
1367                                  sigsetsize, PT_OLD_TIMESPEC);
1368 }
1369 
1370 #endif
1371 
1372 #if defined(CONFIG_COMPAT_32BIT_TIME)
1373 COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, ufds,
1374         unsigned int,  nfds, struct old_timespec32 __user *, tsp,
1375         const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1376 {
1377         struct timespec64 ts, end_time, *to = NULL;
1378         int ret;
1379 
1380         if (tsp) {
1381                 if (get_old_timespec32(&ts, tsp))
1382                         return -EFAULT;
1383 
1384                 to = &end_time;
1385                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1386                         return -EINVAL;
1387         }
1388 
1389         ret = set_compat_user_sigmask(sigmask, sigsetsize);
1390         if (ret)
1391                 return ret;
1392 
1393         ret = do_sys_poll(ufds, nfds, to);
1394         return poll_select_finish(&end_time, tsp, PT_OLD_TIMESPEC, ret);
1395 }
1396 #endif
1397 
1398 /* New compat syscall for 64 bit time_t*/
1399 COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd __user *, ufds,
1400         unsigned int,  nfds, struct __kernel_timespec __user *, tsp,
1401         const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
1402 {
1403         struct timespec64 ts, end_time, *to = NULL;
1404         int ret;
1405 
1406         if (tsp) {
1407                 if (get_timespec64(&ts, tsp))
1408                         return -EFAULT;
1409 
1410                 to = &end_time;
1411                 if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
1412                         return -EINVAL;
1413         }
1414 
1415         ret = set_compat_user_sigmask(sigmask, sigsetsize);
1416         if (ret)
1417                 return ret;
1418 
1419         ret = do_sys_poll(ufds, nfds, to);
1420         return poll_select_finish(&end_time, tsp, PT_TIMESPEC, ret);
1421 }
1422 
1423 #endif
/* [<][>][^][v][top][bottom][index][help] */
root/fs/select.c

DEFINITIONS
