linux/arch/um/os-Linux/irq.c
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   1/*
   2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3 * Licensed under the GPL
   4 */
   5
   6#include <stdlib.h>
   7#include <errno.h>
   8#include <poll.h>
   9#include <signal.h>
  10#include <string.h>
  11#include "irq_user.h"
  12#include "os.h"
  13#include "um_malloc.h"
  14
  15/*
  16 * Locked by irq_lock in arch/um/kernel/irq.c.  Changed by os_create_pollfd
  17 * and os_free_irq_by_cb, which are called under irq_lock.
  18 */
  19static struct pollfd *pollfds = NULL;
  20static int pollfds_num = 0;
  21static int pollfds_size = 0;
  22
  23int os_waiting_for_events(struct irq_fd *active_fds)
  24{
  25        struct irq_fd *irq_fd;
  26        int i, n, err;
  27
  28        n = poll(pollfds, pollfds_num, 0);
  29        if (n < 0) {
  30                err = -errno;
  31                if (errno != EINTR)
  32                        printk(UM_KERN_ERR "os_waiting_for_events:"
  33                               " poll returned %d, errno = %d\n", n, errno);
  34                return err;
  35        }
  36
  37        if (n == 0)
  38                return 0;
  39
  40        irq_fd = active_fds;
  41
  42        for (i = 0; i < pollfds_num; i++) {
  43                if (pollfds[i].revents != 0) {
  44                        irq_fd->current_events = pollfds[i].revents;
  45                        pollfds[i].fd = -1;
  46                }
  47                irq_fd = irq_fd->next;
  48        }
  49        return n;
  50}
  51
  52int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
  53{
  54        if (pollfds_num == pollfds_size) {
  55                if (size_tmpfds <= pollfds_size * sizeof(pollfds[0])) {
  56                        /* return min size needed for new pollfds area */
  57                        return (pollfds_size + 1) * sizeof(pollfds[0]);
  58                }
  59
  60                if (pollfds != NULL) {
  61                        memcpy(tmp_pfd, pollfds,
  62                               sizeof(pollfds[0]) * pollfds_size);
  63                        /* remove old pollfds */
  64                        kfree(pollfds);
  65                }
  66                pollfds = tmp_pfd;
  67                pollfds_size++;
  68        } else
  69                kfree(tmp_pfd); /* remove not used tmp_pfd */
  70
  71        pollfds[pollfds_num] = ((struct pollfd) { .fd           = fd,
  72                                                  .events       = events,
  73                                                  .revents      = 0 });
  74        pollfds_num++;
  75
  76        return 0;
  77}
  78
  79void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
  80                struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2)
  81{
  82        struct irq_fd **prev;
  83        int i = 0;
  84
  85        prev = &active_fds;
  86        while (*prev != NULL) {
  87                if ((*test)(*prev, arg)) {
  88                        struct irq_fd *old_fd = *prev;
  89                        if ((pollfds[i].fd != -1) &&
  90                            (pollfds[i].fd != (*prev)->fd)) {
  91                                printk(UM_KERN_ERR "os_free_irq_by_cb - "
  92                                       "mismatch between active_fds and "
  93                                       "pollfds, fd %d vs %d\n",
  94                                       (*prev)->fd, pollfds[i].fd);
  95                                goto out;
  96                        }
  97
  98                        pollfds_num--;
  99
 100                        /*
 101                         * This moves the *whole* array after pollfds[i]
 102                         * (though it doesn't spot as such)!
 103                         */
 104                        memmove(&pollfds[i], &pollfds[i + 1],
 105                               (pollfds_num - i) * sizeof(pollfds[0]));
 106                        if (*last_irq_ptr2 == &old_fd->next)
 107                                *last_irq_ptr2 = prev;
 108
 109                        *prev = (*prev)->next;
 110                        if (old_fd->type == IRQ_WRITE)
 111                                ignore_sigio_fd(old_fd->fd);
 112                        kfree(old_fd);
 113                        continue;
 114                }
 115                prev = &(*prev)->next;
 116                i++;
 117        }
 118 out:
 119        return;
 120}
 121
 122int os_get_pollfd(int i)
 123{
 124        return pollfds[i].fd;
 125}
 126
 127void os_set_pollfd(int i, int fd)
 128{
 129        pollfds[i].fd = fd;
 130}
 131
 132void os_set_ioignore(void)
 133{
 134        signal(SIGIO, SIG_IGN);
 135}
 136
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