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841 lines
20 KiB
841 lines
20 KiB
/*
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* This file contains the procedures for the handling of select and poll
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*
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* Created for Linux based loosely upon Mathius Lattner's minix
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* patches by Peter MacDonald. Heavily edited by Linus.
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*
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* 4 February 1994
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* COFF/ELF binary emulation. If the process has the STICKY_TIMEOUTS
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* flag set in its personality we do *not* modify the given timeout
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* parameter to reflect time remaining.
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*
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* 24 January 2000
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* Changed sys_poll()/do_poll() to use PAGE_SIZE chunk-based allocation
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* of fds to overcome nfds < 16390 descriptors limit (Tigran Aivazian).
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*/
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#include <linux/syscalls.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/smp_lock.h>
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#include <linux/poll.h>
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#include <linux/personality.h> /* for STICKY_TIMEOUTS */
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#include <linux/file.h>
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#include <linux/fs.h>
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#include <linux/rcupdate.h>
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#include <asm/uaccess.h>
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#define ROUND_UP(x,y) (((x)+(y)-1)/(y))
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#define DEFAULT_POLLMASK (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM)
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struct poll_table_page {
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struct poll_table_page * next;
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struct poll_table_entry * entry;
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struct poll_table_entry entries[0];
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};
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#define POLL_TABLE_FULL(table) \
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((unsigned long)((table)->entry+1) > PAGE_SIZE + (unsigned long)(table))
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/*
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* Ok, Peter made a complicated, but straightforward multiple_wait() function.
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* I have rewritten this, taking some shortcuts: This code may not be easy to
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* follow, but it should be free of race-conditions, and it's practical. If you
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* understand what I'm doing here, then you understand how the linux
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* sleep/wakeup mechanism works.
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*
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* Two very simple procedures, poll_wait() and poll_freewait() make all the
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* work. poll_wait() is an inline-function defined in <linux/poll.h>,
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* as all select/poll functions have to call it to add an entry to the
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* poll table.
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*/
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static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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poll_table *p);
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void poll_initwait(struct poll_wqueues *pwq)
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{
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init_poll_funcptr(&pwq->pt, __pollwait);
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pwq->error = 0;
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pwq->table = NULL;
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pwq->inline_index = 0;
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}
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EXPORT_SYMBOL(poll_initwait);
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static void free_poll_entry(struct poll_table_entry *entry)
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{
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remove_wait_queue(entry->wait_address,&entry->wait);
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fput(entry->filp);
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}
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void poll_freewait(struct poll_wqueues *pwq)
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{
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struct poll_table_page * p = pwq->table;
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int i;
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for (i = 0; i < pwq->inline_index; i++)
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free_poll_entry(pwq->inline_entries + i);
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while (p) {
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struct poll_table_entry * entry;
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struct poll_table_page *old;
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entry = p->entry;
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do {
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entry--;
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free_poll_entry(entry);
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} while (entry > p->entries);
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old = p;
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p = p->next;
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free_page((unsigned long) old);
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}
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}
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EXPORT_SYMBOL(poll_freewait);
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static struct poll_table_entry *poll_get_entry(poll_table *_p)
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{
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struct poll_wqueues *p = container_of(_p, struct poll_wqueues, pt);
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struct poll_table_page *table = p->table;
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if (p->inline_index < N_INLINE_POLL_ENTRIES)
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return p->inline_entries + p->inline_index++;
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if (!table || POLL_TABLE_FULL(table)) {
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struct poll_table_page *new_table;
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new_table = (struct poll_table_page *) __get_free_page(GFP_KERNEL);
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if (!new_table) {
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p->error = -ENOMEM;
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__set_current_state(TASK_RUNNING);
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return NULL;
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}
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new_table->entry = new_table->entries;
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new_table->next = table;
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p->table = new_table;
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table = new_table;
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}
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return table->entry++;
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}
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/* Add a new entry */
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static void __pollwait(struct file *filp, wait_queue_head_t *wait_address,
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poll_table *p)
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{
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struct poll_table_entry *entry = poll_get_entry(p);
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if (!entry)
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return;
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get_file(filp);
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entry->filp = filp;
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entry->wait_address = wait_address;
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init_waitqueue_entry(&entry->wait, current);
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add_wait_queue(wait_address,&entry->wait);
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}
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#define FDS_IN(fds, n) (fds->in + n)
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#define FDS_OUT(fds, n) (fds->out + n)
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#define FDS_EX(fds, n) (fds->ex + n)
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#define BITS(fds, n) (*FDS_IN(fds, n)|*FDS_OUT(fds, n)|*FDS_EX(fds, n))
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static int max_select_fd(unsigned long n, fd_set_bits *fds)
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{
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unsigned long *open_fds;
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unsigned long set;
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int max;
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struct fdtable *fdt;
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/* handle last in-complete long-word first */
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set = ~(~0UL << (n & (__NFDBITS-1)));
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n /= __NFDBITS;
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fdt = files_fdtable(current->files);
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open_fds = fdt->open_fds->fds_bits+n;
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max = 0;
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if (set) {
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set &= BITS(fds, n);
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if (set) {
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if (!(set & ~*open_fds))
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goto get_max;
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return -EBADF;
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}
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}
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while (n) {
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open_fds--;
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n--;
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set = BITS(fds, n);
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if (!set)
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continue;
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if (set & ~*open_fds)
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return -EBADF;
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if (max)
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continue;
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get_max:
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do {
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max++;
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set >>= 1;
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} while (set);
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max += n * __NFDBITS;
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}
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return max;
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}
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#define BIT(i) (1UL << ((i)&(__NFDBITS-1)))
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#define MEM(i,m) ((m)+(unsigned)(i)/__NFDBITS)
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#define ISSET(i,m) (((i)&*(m)) != 0)
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#define SET(i,m) (*(m) |= (i))
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#define POLLIN_SET (POLLRDNORM | POLLRDBAND | POLLIN | POLLHUP | POLLERR)
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#define POLLOUT_SET (POLLWRBAND | POLLWRNORM | POLLOUT | POLLERR)
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#define POLLEX_SET (POLLPRI)
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int do_select(int n, fd_set_bits *fds, s64 *timeout)
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{
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struct poll_wqueues table;
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poll_table *wait;
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int retval, i;
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rcu_read_lock();
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retval = max_select_fd(n, fds);
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rcu_read_unlock();
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if (retval < 0)
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return retval;
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n = retval;
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poll_initwait(&table);
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wait = &table.pt;
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if (!*timeout)
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wait = NULL;
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retval = 0;
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for (;;) {
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unsigned long *rinp, *routp, *rexp, *inp, *outp, *exp;
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long __timeout;
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set_current_state(TASK_INTERRUPTIBLE);
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inp = fds->in; outp = fds->out; exp = fds->ex;
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rinp = fds->res_in; routp = fds->res_out; rexp = fds->res_ex;
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for (i = 0; i < n; ++rinp, ++routp, ++rexp) {
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unsigned long in, out, ex, all_bits, bit = 1, mask, j;
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unsigned long res_in = 0, res_out = 0, res_ex = 0;
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const struct file_operations *f_op = NULL;
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struct file *file = NULL;
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in = *inp++; out = *outp++; ex = *exp++;
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all_bits = in | out | ex;
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if (all_bits == 0) {
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i += __NFDBITS;
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continue;
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}
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for (j = 0; j < __NFDBITS; ++j, ++i, bit <<= 1) {
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int fput_needed;
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if (i >= n)
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break;
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if (!(bit & all_bits))
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continue;
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file = fget_light(i, &fput_needed);
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if (file) {
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f_op = file->f_op;
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mask = DEFAULT_POLLMASK;
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if (f_op && f_op->poll)
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mask = (*f_op->poll)(file, retval ? NULL : wait);
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fput_light(file, fput_needed);
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if ((mask & POLLIN_SET) && (in & bit)) {
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res_in |= bit;
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retval++;
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}
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if ((mask & POLLOUT_SET) && (out & bit)) {
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res_out |= bit;
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retval++;
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}
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if ((mask & POLLEX_SET) && (ex & bit)) {
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res_ex |= bit;
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retval++;
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}
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}
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cond_resched();
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}
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if (res_in)
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*rinp = res_in;
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if (res_out)
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*routp = res_out;
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if (res_ex)
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*rexp = res_ex;
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}
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wait = NULL;
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if (retval || !*timeout || signal_pending(current))
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break;
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if(table.error) {
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retval = table.error;
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break;
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}
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if (*timeout < 0) {
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/* Wait indefinitely */
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__timeout = MAX_SCHEDULE_TIMEOUT;
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} else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT - 1)) {
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/* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in a loop */
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__timeout = MAX_SCHEDULE_TIMEOUT - 1;
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*timeout -= __timeout;
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} else {
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__timeout = *timeout;
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*timeout = 0;
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}
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__timeout = schedule_timeout(__timeout);
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if (*timeout >= 0)
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*timeout += __timeout;
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}
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__set_current_state(TASK_RUNNING);
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poll_freewait(&table);
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return retval;
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}
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/*
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* We can actually return ERESTARTSYS instead of EINTR, but I'd
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* like to be certain this leads to no problems. So I return
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* EINTR just for safety.
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*
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* Update: ERESTARTSYS breaks at least the xview clock binary, so
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* I'm trying ERESTARTNOHAND which restart only when you want to.
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*/
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#define MAX_SELECT_SECONDS \
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((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)
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static int core_sys_select(int n, fd_set __user *inp, fd_set __user *outp,
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fd_set __user *exp, s64 *timeout)
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{
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fd_set_bits fds;
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void *bits;
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int ret, max_fdset;
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unsigned int size;
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struct fdtable *fdt;
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/* Allocate small arguments on the stack to save memory and be faster */
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long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];
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ret = -EINVAL;
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if (n < 0)
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goto out_nofds;
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/* max_fdset can increase, so grab it once to avoid race */
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rcu_read_lock();
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fdt = files_fdtable(current->files);
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max_fdset = fdt->max_fdset;
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rcu_read_unlock();
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if (n > max_fdset)
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n = max_fdset;
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/*
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* We need 6 bitmaps (in/out/ex for both incoming and outgoing),
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* since we used fdset we need to allocate memory in units of
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* long-words.
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*/
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size = FDS_BYTES(n);
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bits = stack_fds;
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if (size > sizeof(stack_fds) / 6) {
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/* Not enough space in on-stack array; must use kmalloc */
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ret = -ENOMEM;
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bits = kmalloc(6 * size, GFP_KERNEL);
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if (!bits)
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goto out_nofds;
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}
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fds.in = bits;
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fds.out = bits + size;
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fds.ex = bits + 2*size;
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fds.res_in = bits + 3*size;
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fds.res_out = bits + 4*size;
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fds.res_ex = bits + 5*size;
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if ((ret = get_fd_set(n, inp, fds.in)) ||
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(ret = get_fd_set(n, outp, fds.out)) ||
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(ret = get_fd_set(n, exp, fds.ex)))
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goto out;
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zero_fd_set(n, fds.res_in);
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zero_fd_set(n, fds.res_out);
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zero_fd_set(n, fds.res_ex);
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ret = do_select(n, &fds, timeout);
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if (ret < 0)
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goto out;
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if (!ret) {
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ret = -ERESTARTNOHAND;
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if (signal_pending(current))
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goto out;
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ret = 0;
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}
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if (set_fd_set(n, inp, fds.res_in) ||
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set_fd_set(n, outp, fds.res_out) ||
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set_fd_set(n, exp, fds.res_ex))
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ret = -EFAULT;
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out:
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if (bits != stack_fds)
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kfree(bits);
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out_nofds:
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return ret;
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}
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asmlinkage long sys_select(int n, fd_set __user *inp, fd_set __user *outp,
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fd_set __user *exp, struct timeval __user *tvp)
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{
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s64 timeout = -1;
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struct timeval tv;
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int ret;
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if (tvp) {
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if (copy_from_user(&tv, tvp, sizeof(tv)))
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return -EFAULT;
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if (tv.tv_sec < 0 || tv.tv_usec < 0)
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return -EINVAL;
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/* Cast to u64 to make GCC stop complaining */
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if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
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timeout = -1; /* infinite */
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else {
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timeout = ROUND_UP(tv.tv_usec, USEC_PER_SEC/HZ);
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timeout += tv.tv_sec * HZ;
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}
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}
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ret = core_sys_select(n, inp, outp, exp, &timeout);
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if (tvp) {
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struct timeval rtv;
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if (current->personality & STICKY_TIMEOUTS)
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goto sticky;
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rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
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rtv.tv_sec = timeout;
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if (timeval_compare(&rtv, &tv) >= 0)
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rtv = tv;
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if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
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sticky:
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/*
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* If an application puts its timeval in read-only
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* memory, we don't want the Linux-specific update to
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* the timeval to cause a fault after the select has
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* completed successfully. However, because we're not
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* updating the timeval, we can't restart the system
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* call.
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*/
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if (ret == -ERESTARTNOHAND)
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ret = -EINTR;
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}
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}
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return ret;
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}
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#ifdef TIF_RESTORE_SIGMASK
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asmlinkage long sys_pselect7(int n, fd_set __user *inp, fd_set __user *outp,
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fd_set __user *exp, struct timespec __user *tsp,
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const sigset_t __user *sigmask, size_t sigsetsize)
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{
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s64 timeout = MAX_SCHEDULE_TIMEOUT;
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sigset_t ksigmask, sigsaved;
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struct timespec ts;
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int ret;
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|
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if (tsp) {
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if (copy_from_user(&ts, tsp, sizeof(ts)))
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return -EFAULT;
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|
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if (ts.tv_sec < 0 || ts.tv_nsec < 0)
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return -EINVAL;
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|
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/* Cast to u64 to make GCC stop complaining */
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if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
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timeout = -1; /* infinite */
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else {
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timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
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timeout += ts.tv_sec * HZ;
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}
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}
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|
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if (sigmask) {
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/* XXX: Don't preclude handling different sized sigset_t's. */
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if (sigsetsize != sizeof(sigset_t))
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return -EINVAL;
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if (copy_from_user(&ksigmask, sigmask, sizeof(ksigmask)))
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return -EFAULT;
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|
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sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
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sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
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}
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ret = core_sys_select(n, inp, outp, exp, &timeout);
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|
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if (tsp) {
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struct timespec rts;
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if (current->personality & STICKY_TIMEOUTS)
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goto sticky;
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rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
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1000;
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rts.tv_sec = timeout;
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if (timespec_compare(&rts, &ts) >= 0)
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rts = ts;
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if (copy_to_user(tsp, &rts, sizeof(rts))) {
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sticky:
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/*
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* If an application puts its timeval in read-only
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* memory, we don't want the Linux-specific update to
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* the timeval to cause a fault after the select has
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* completed successfully. However, because we're not
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* updating the timeval, we can't restart the system
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* call.
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*/
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if (ret == -ERESTARTNOHAND)
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ret = -EINTR;
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}
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}
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|
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if (ret == -ERESTARTNOHAND) {
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|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
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* the signal on the way back to userspace, before the signal
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* mask is restored.
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|
*/
|
|
if (sigmask) {
|
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memcpy(¤t->saved_sigmask, &sigsaved,
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sizeof(sigsaved));
|
|
set_thread_flag(TIF_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.
|
|
*/
|
|
asmlinkage long sys_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 sys_pselect7(n, inp, outp, exp, tsp, up, sigsetsize);
|
|
}
|
|
#endif /* TIF_RESTORE_SIGMASK */
|
|
|
|
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 non-NULL.
|
|
*/
|
|
static inline unsigned int do_pollfd(struct pollfd *pollfd, poll_table *pwait)
|
|
{
|
|
unsigned int mask;
|
|
int fd;
|
|
|
|
mask = 0;
|
|
fd = pollfd->fd;
|
|
if (fd >= 0) {
|
|
int fput_needed;
|
|
struct file * file;
|
|
|
|
file = fget_light(fd, &fput_needed);
|
|
mask = POLLNVAL;
|
|
if (file != NULL) {
|
|
mask = DEFAULT_POLLMASK;
|
|
if (file->f_op && file->f_op->poll)
|
|
mask = file->f_op->poll(file, pwait);
|
|
/* Mask out unneeded events. */
|
|
mask &= pollfd->events | POLLERR | POLLHUP;
|
|
fput_light(file, fput_needed);
|
|
}
|
|
}
|
|
pollfd->revents = mask;
|
|
|
|
return mask;
|
|
}
|
|
|
|
static int do_poll(unsigned int nfds, struct poll_list *list,
|
|
struct poll_wqueues *wait, s64 *timeout)
|
|
{
|
|
int count = 0;
|
|
poll_table* pt = &wait->pt;
|
|
|
|
/* Optimise the no-wait case */
|
|
if (!(*timeout))
|
|
pt = NULL;
|
|
|
|
for (;;) {
|
|
struct poll_list *walk;
|
|
long __timeout;
|
|
|
|
set_current_state(TASK_INTERRUPTIBLE);
|
|
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 the poll_table, 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)) {
|
|
count++;
|
|
pt = NULL;
|
|
}
|
|
}
|
|
}
|
|
/*
|
|
* All waiters have already been registered, so don't provide
|
|
* a poll_table to them on the next loop iteration.
|
|
*/
|
|
pt = NULL;
|
|
if (count || !*timeout || signal_pending(current))
|
|
break;
|
|
count = wait->error;
|
|
if (count)
|
|
break;
|
|
|
|
if (*timeout < 0) {
|
|
/* Wait indefinitely */
|
|
__timeout = MAX_SCHEDULE_TIMEOUT;
|
|
} else if (unlikely(*timeout >= (s64)MAX_SCHEDULE_TIMEOUT-1)) {
|
|
/*
|
|
* Wait for longer than MAX_SCHEDULE_TIMEOUT. Do it in
|
|
* a loop
|
|
*/
|
|
__timeout = MAX_SCHEDULE_TIMEOUT - 1;
|
|
*timeout -= __timeout;
|
|
} else {
|
|
__timeout = *timeout;
|
|
*timeout = 0;
|
|
}
|
|
|
|
__timeout = schedule_timeout(__timeout);
|
|
if (*timeout >= 0)
|
|
*timeout += __timeout;
|
|
}
|
|
__set_current_state(TASK_RUNNING);
|
|
return count;
|
|
}
|
|
|
|
#define N_STACK_PPS ((sizeof(stack_pps) - sizeof(struct poll_list)) / \
|
|
sizeof(struct pollfd))
|
|
|
|
int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds, s64 *timeout)
|
|
{
|
|
struct poll_wqueues table;
|
|
int fdcount, err;
|
|
unsigned int i;
|
|
struct poll_list *head;
|
|
struct poll_list *walk;
|
|
/* 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 *stack_pp = NULL;
|
|
|
|
/* Do a sanity check on nfds ... */
|
|
if (nfds > current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
|
|
return -EINVAL;
|
|
|
|
poll_initwait(&table);
|
|
|
|
head = NULL;
|
|
walk = NULL;
|
|
i = nfds;
|
|
err = -ENOMEM;
|
|
while(i!=0) {
|
|
struct poll_list *pp;
|
|
int num, size;
|
|
if (stack_pp == NULL)
|
|
num = N_STACK_PPS;
|
|
else
|
|
num = POLLFD_PER_PAGE;
|
|
if (num > i)
|
|
num = i;
|
|
size = sizeof(struct poll_list) + sizeof(struct pollfd)*num;
|
|
if (!stack_pp)
|
|
stack_pp = pp = (struct poll_list *)stack_pps;
|
|
else {
|
|
pp = kmalloc(size, GFP_KERNEL);
|
|
if (!pp)
|
|
goto out_fds;
|
|
}
|
|
pp->next=NULL;
|
|
pp->len = num;
|
|
if (head == NULL)
|
|
head = pp;
|
|
else
|
|
walk->next = pp;
|
|
|
|
walk = pp;
|
|
if (copy_from_user(pp->entries, ufds + nfds-i,
|
|
sizeof(struct pollfd)*num)) {
|
|
err = -EFAULT;
|
|
goto out_fds;
|
|
}
|
|
i -= pp->len;
|
|
}
|
|
|
|
fdcount = do_poll(nfds, head, &table, timeout);
|
|
|
|
/* OK, now copy the revents fields back to user space. */
|
|
walk = head;
|
|
err = -EFAULT;
|
|
while(walk != NULL) {
|
|
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;
|
|
}
|
|
walk = walk->next;
|
|
}
|
|
err = fdcount;
|
|
if (!fdcount && signal_pending(current))
|
|
err = -EINTR;
|
|
out_fds:
|
|
walk = head;
|
|
while(walk!=NULL) {
|
|
struct poll_list *pp = walk->next;
|
|
if (walk != stack_pp)
|
|
kfree(walk);
|
|
walk = pp;
|
|
}
|
|
poll_freewait(&table);
|
|
return err;
|
|
}
|
|
|
|
asmlinkage long sys_poll(struct pollfd __user *ufds, unsigned int nfds,
|
|
long timeout_msecs)
|
|
{
|
|
s64 timeout_jiffies;
|
|
|
|
if (timeout_msecs > 0) {
|
|
#if HZ > 1000
|
|
/* We can only overflow if HZ > 1000 */
|
|
if (timeout_msecs / 1000 > (s64)0x7fffffffffffffffULL / (s64)HZ)
|
|
timeout_jiffies = -1;
|
|
else
|
|
#endif
|
|
timeout_jiffies = msecs_to_jiffies(timeout_msecs);
|
|
} else {
|
|
/* Infinite (< 0) or no (0) timeout */
|
|
timeout_jiffies = timeout_msecs;
|
|
}
|
|
|
|
return do_sys_poll(ufds, nfds, &timeout_jiffies);
|
|
}
|
|
|
|
#ifdef TIF_RESTORE_SIGMASK
|
|
asmlinkage long sys_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;
|
|
s64 timeout = -1;
|
|
int ret;
|
|
|
|
if (tsp) {
|
|
if (copy_from_user(&ts, tsp, sizeof(ts)))
|
|
return -EFAULT;
|
|
|
|
/* Cast to u64 to make GCC stop complaining */
|
|
if ((u64)ts.tv_sec >= (u64)MAX_INT64_SECONDS)
|
|
timeout = -1; /* infinite */
|
|
else {
|
|
timeout = ROUND_UP(ts.tv_nsec, NSEC_PER_SEC/HZ);
|
|
timeout += ts.tv_sec * HZ;
|
|
}
|
|
}
|
|
|
|
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, &timeout);
|
|
|
|
/* We can restart this syscall, usually */
|
|
if (ret == -EINTR) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_thread_flag(TIF_RESTORE_SIGMASK);
|
|
}
|
|
ret = -ERESTARTNOHAND;
|
|
} else if (sigmask)
|
|
sigprocmask(SIG_SETMASK, &sigsaved, NULL);
|
|
|
|
if (tsp && timeout >= 0) {
|
|
struct timespec rts;
|
|
|
|
if (current->personality & STICKY_TIMEOUTS)
|
|
goto sticky;
|
|
/* Yes, we know it's actually an s64, but it's also positive. */
|
|
rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
|
|
1000;
|
|
rts.tv_sec = timeout;
|
|
if (timespec_compare(&rts, &ts) >= 0)
|
|
rts = ts;
|
|
if (copy_to_user(tsp, &rts, sizeof(rts))) {
|
|
sticky:
|
|
/*
|
|
* 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.
|
|
*/
|
|
if (ret == -ERESTARTNOHAND && timeout >= 0)
|
|
ret = -EINTR;
|
|
}
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#endif /* TIF_RESTORE_SIGMASK */
|
|
|