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![Vadim Lobanov](/assets/img/avatar_default.png)
Currently, each fdtable supports three dynamically-sized arrays of data: the fdarray and two fdsets. The code allows the number of fds supported by the fdarray (fdtable->max_fds) to differ from the number of fds supported by each of the fdsets (fdtable->max_fdset). In practice, it is wasteful for these two sizes to differ: whenever we hit a limit on the smaller-capacity structure, we will reallocate the entire fdtable and all the dynamic arrays within it, so any delta in the memory used by the larger-capacity structure will never be touched at all. Rather than hogging this excess, we shouldn't even allocate it in the first place, and keep the capacities of the fdarray and the fdsets equal. This patch removes fdtable->max_fdset. As an added bonus, most of the supporting code becomes simpler. Signed-off-by: Vadim Lobanov <vlobanov@speakeasy.net> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
841 lines
20 KiB
C
841 lines
20 KiB
C
/*
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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_fds;
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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_fds 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_fds = fdt->max_fds;
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rcu_read_unlock();
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if (n > max_fds)
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n = max_fds;
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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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if (tsp) {
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if (copy_from_user(&ts, tsp, sizeof(ts)))
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return -EFAULT;
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if (ts.tv_sec < 0 || ts.tv_nsec < 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)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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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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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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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))) {
|
|
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)
|
|
ret = -EINTR;
|
|
}
|
|
}
|
|
|
|
if (ret == -ERESTARTNOHAND) {
|
|
/*
|
|
* Don't restore the signal mask yet. Let do_signal() deliver
|
|
* the signal on the way back to userspace, before the signal
|
|
* mask is restored.
|
|
*/
|
|
if (sigmask) {
|
|
memcpy(¤t->saved_sigmask, &sigsaved,
|
|
sizeof(sigsaved));
|
|
set_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 */
|