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