linux/fs/select.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

1433 lines
35 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* 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/signal.h>
#include <linux/sched/rt.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/freezer.h>
#include <net/busy_poll.h>
#include <linux/vmalloc.h>
#include <linux/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_entry_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_entry_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;
}
/*
* Scalable version of the fd_set.
*/
typedef struct {
unsigned long *in, *out, *ex;
unsigned long *res_in, *res_out, *res_ex;
} fd_set_bits;
/*
* How many longwords for "nr" bits?
*/
#define FDS_BITPERLONG (8*sizeof(long))
#define FDS_LONGS(nr) (((nr)+FDS_BITPERLONG-1)/FDS_BITPERLONG)
#define FDS_BYTES(nr) (FDS_LONGS(nr)*sizeof(long))
/*
* We do a VERIFY_WRITE here even though we are only reading this time:
* we'll write to it eventually..
*
* Use "unsigned long" accesses to let user-mode fd_set's be long-aligned.
*/
static inline
int get_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
{
nr = FDS_BYTES(nr);
if (ufdset)
return copy_from_user(fdset, ufdset, nr) ? -EFAULT : 0;
memset(fdset, 0, nr);
return 0;
}
static inline unsigned long __must_check
set_fd_set(unsigned long nr, void __user *ufdset, unsigned long *fdset)
{
if (ufdset)
return __copy_to_user(ufdset, fdset, FDS_BYTES(nr));
return 0;
}
static inline
void zero_fd_set(unsigned long nr, unsigned long *fdset)
{
memset(fdset, 0, FDS_BYTES(nr));
}
#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;
}
static 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_start = 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_start) {
busy_start = busy_loop_current_time();
continue;
}
if (!busy_loop_timeout(busy_start))
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;
size_t size, alloc_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;
if (size > (SIZE_MAX / 6))
goto out_nofds;
alloc_size = 6 * size;
bits = kvmalloc(alloc_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)
kvfree(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(&current->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_start = 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_start) {
busy_start = busy_loop_current_time();
continue;
}
if (!busy_loop_timeout(busy_start))
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))
static 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 = &current->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(&current->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;
}
#ifdef CONFIG_COMPAT
#define __COMPAT_NFDBITS (8 * sizeof(compat_ulong_t))
static
int compat_poll_select_copy_remaining(struct timespec *end_time, void __user *p,
int timeval, int ret)
{
struct timespec ts;
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_ts(&ts);
ts = timespec_sub(*end_time, ts);
if (ts.tv_sec < 0)
ts.tv_sec = ts.tv_nsec = 0;
if (timeval) {
struct compat_timeval rtv;
rtv.tv_sec = ts.tv_sec;
rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
if (!copy_to_user(p, &rtv, sizeof(rtv)))
return ret;
} else {
struct compat_timespec rts;
rts.tv_sec = ts.tv_sec;
rts.tv_nsec = ts.tv_nsec;
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;
}
/*
* Ooo, nasty. We need here to frob 32-bit unsigned longs to
* 64-bit unsigned longs.
*/
static
int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
if (ufdset) {
return compat_get_bitmap(fdset, ufdset, nr);
} else {
zero_fd_set(nr, fdset);
return 0;
}
}
static
int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
unsigned long *fdset)
{
if (!ufdset)
return 0;
return compat_put_bitmap(ufdset, fdset, nr);
}
/*
* This is a virtual copy of sys_select from fs/select.c and probably
* should be compared to it from time to time
*/
/*
* 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.
*/
static int compat_core_sys_select(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct timespec *end_time)
{
fd_set_bits fds;
void *bits;
int size, max_fds, ret = -EINVAL;
struct fdtable *fdt;
long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
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) {
bits = kmalloc(6 * size, GFP_KERNEL);
ret = -ENOMEM;
if (!bits)
goto out_nofds;
}
fds.in = (unsigned long *) bits;
fds.out = (unsigned long *) (bits + size);
fds.ex = (unsigned long *) (bits + 2*size);
fds.res_in = (unsigned long *) (bits + 3*size);
fds.res_out = (unsigned long *) (bits + 4*size);
fds.res_ex = (unsigned long *) (bits + 5*size);
if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
(ret = compat_get_fd_set(n, outp, fds.out)) ||
(ret = compat_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 (compat_set_fd_set(n, inp, fds.res_in) ||
compat_set_fd_set(n, outp, fds.res_out) ||
compat_set_fd_set(n, exp, fds.res_ex))
ret = -EFAULT;
out:
if (bits != stack_fds)
kfree(bits);
out_nofds:
return ret;
}
COMPAT_SYSCALL_DEFINE5(select, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct compat_timeval __user *, tvp)
{
struct timespec end_time, *to = NULL;
struct compat_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 = compat_core_sys_select(n, inp, outp, exp, to);
ret = compat_poll_select_copy_remaining(&end_time, tvp, 1, ret);
return ret;
}
struct compat_sel_arg_struct {
compat_ulong_t n;
compat_uptr_t inp;
compat_uptr_t outp;
compat_uptr_t exp;
compat_uptr_t tvp;
};
COMPAT_SYSCALL_DEFINE1(old_select, struct compat_sel_arg_struct __user *, arg)
{
struct compat_sel_arg_struct a;
if (copy_from_user(&a, arg, sizeof(a)))
return -EFAULT;
return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
compat_ptr(a.exp), compat_ptr(a.tvp));
}
static long do_compat_pselect(int n, compat_ulong_t __user *inp,
compat_ulong_t __user *outp, compat_ulong_t __user *exp,
struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask,
compat_size_t sigsetsize)
{
compat_sigset_t ss32;
sigset_t ksigmask, sigsaved;
struct compat_timespec ts;
struct timespec 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) {
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
return -EFAULT;
sigset_from_compat(&ksigmask, &ss32);
sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
}
ret = compat_core_sys_select(n, inp, outp, exp, to);
ret = compat_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(&current->saved_sigmask, &sigsaved,
sizeof(sigsaved));
set_restore_sigmask();
}
} else if (sigmask)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
return ret;
}
COMPAT_SYSCALL_DEFINE6(pselect6, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct compat_timespec __user *, tsp, void __user *, sig)
{
compat_size_t sigsetsize = 0;
compat_uptr_t up = 0;
if (sig) {
if (!access_ok(VERIFY_READ, sig,
sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
__get_user(up, (compat_uptr_t __user *)sig) ||
__get_user(sigsetsize,
(compat_size_t __user *)(sig+sizeof(up))))
return -EFAULT;
}
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
sigsetsize);
}
COMPAT_SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds,
unsigned int, nfds, struct compat_timespec __user *, tsp,
const compat_sigset_t __user *, sigmask, compat_size_t, sigsetsize)
{
compat_sigset_t ss32;
sigset_t ksigmask, sigsaved;
struct compat_timespec ts;
struct timespec 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) {
if (sigsetsize != sizeof(compat_sigset_t))
return -EINVAL;
if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
return -EFAULT;
sigset_from_compat(&ksigmask, &ss32);
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(&current->saved_sigmask, &sigsaved,
sizeof(sigsaved));
set_restore_sigmask();
}
ret = -ERESTARTNOHAND;
} else if (sigmask)
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
ret = compat_poll_select_copy_remaining(&end_time, tsp, 0, ret);
return ret;
}
#endif