arch/um/os-Linux/irq.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <signal.h>
  10 #include <string.h>
  11 #include <sys/poll.h>
  12 #include <sys/types.h>
  13 #include <sys/time.h>
  14 #include "user_util.h"
  15 #include "kern_util.h"
  16 #include "user.h"
  17 #include "process.h"
  18 #include "sigio.h"
  19 #include "irq_user.h"
  20 #include "os.h"
  21 #include "um_malloc.h"
  22
  23 /*
  24  * Locked by irq_lock in arch/um/kernel/irq.c.  Changed by os_create_pollfd
  25  * and os_free_irq_by_cb, which are called under irq_lock.
  26  */
  27 static struct pollfd *pollfds = NULL;
  28 static int pollfds_num = 0;
  29 static int pollfds_size = 0;
  30
  31 int os_waiting_for_events(struct irq_fd *active_fds)
  32 {
  33         struct irq_fd *irq_fd;
  34         int i, n, err;
  35
  36         n = poll(pollfds, pollfds_num, 0);
  37         if (n < 0) {
  38                 err = -errno;
  39                 if (errno != EINTR)
  40                         printk("sigio_handler: os_waiting_for_events:"
  41                                " poll returned %d, errno = %d\n", n, errno);
  42                 return err;
  43         }
  44
  45         if (n == 0)
  46                 return 0;
  47
  48         irq_fd = active_fds;
  49
  50         for (i = 0; i < pollfds_num; i++) {
  51                 if (pollfds[i].revents != 0) {
  52                         irq_fd->current_events = pollfds[i].revents;
  53                         pollfds[i].fd = -1;
  54                 }
  55                 irq_fd = irq_fd->next;
  56         }
  57         return n;
  58 }
  59
  60 int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
  61 {
  62         if (pollfds_num == pollfds_size) {
  63                 if (size_tmpfds <= pollfds_size * sizeof(pollfds[0])) {
  64                         /* return min size needed for new pollfds area */
  65                         return (pollfds_size + 1) * sizeof(pollfds[0]);
  66                 }
  67
  68                 if (pollfds != NULL) {
  69                         memcpy(tmp_pfd, pollfds,
  70                                sizeof(pollfds[0]) * pollfds_size);
  71                         /* remove old pollfds */
  72                         kfree(pollfds);
  73                 }
  74                 pollfds = tmp_pfd;
  75                 pollfds_size++;
  76         } else
  77                 kfree(tmp_pfd); /* remove not used tmp_pfd */
  78
  79         pollfds[pollfds_num] = ((struct pollfd) { .fd           = fd,
  80                                                   .events       = events,
  81                                                   .revents      = 0 });
  82         pollfds_num++;
  83
  84         return 0;
  85 }
  86
  87 void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
  88                 struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2)
  89 {
  90         struct irq_fd **prev;
  91         int i = 0;
  92
  93         prev = &active_fds;
  94         while (*prev != NULL) {
  95                 if ((*test)(*prev, arg)) {
  96                         struct irq_fd *old_fd = *prev;
  97                         if ((pollfds[i].fd != -1) &&
  98                             (pollfds[i].fd != (*prev)->fd)) {
  99                                 printk("os_free_irq_by_cb - mismatch between "
 100                                        "active_fds and pollfds, fd %d vs %d\n",
 101                                        (*prev)->fd, pollfds[i].fd);
 102                                 goto out;
 103                         }
 104
 105                         pollfds_num--;
 106
 107                         /* This moves the *whole* array after pollfds[i]
 108                          * (though it doesn't spot as such)!
 109                          */
 110                         memmove(&pollfds[i], &pollfds[i + 1],
 111                                (pollfds_num - i) * sizeof(pollfds[0]));
 112                         if(*last_irq_ptr2 == &old_fd->next)
 113                                 *last_irq_ptr2 = prev;
 114
 115                         *prev = (*prev)->next;
 116                         if(old_fd->type == IRQ_WRITE)
 117                                 ignore_sigio_fd(old_fd->fd);
 118                         kfree(old_fd);
 119                         continue;
 120                 }
 121                 prev = &(*prev)->next;
 122                 i++;
 123         }
 124  out:
 125         return;
 126 }
 127
 128 int os_get_pollfd(int i)
 129 {
 130         return pollfds[i].fd;
 131 }
 132
 133 void os_set_pollfd(int i, int fd)
 134 {
 135         pollfds[i].fd = fd;
 136 }
 137
 138 void os_set_ioignore(void)
 139 {
 140         signal(SIGIO, SIG_IGN);
 141 }
 142
 143 void init_irq_signals(int on_sigstack)
 144 {
 145         int flags;
 146
 147         flags = on_sigstack ? SA_ONSTACK : 0;
 148
 149         set_handler(SIGVTALRM, (__sighandler_t) alarm_handler,
 150                     flags | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 151         set_handler(SIGALRM, (__sighandler_t) alarm_handler,
 152                     flags | SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
 153         set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
 154                     SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
 155         signal(SIGWINCH, SIG_IGN);
 156 }