xref: /linux/arch/um/os-Linux/irq.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 
22 static struct pollfd *pollfds = NULL;
23 static int pollfds_num = 0;
24 static int pollfds_size = 0;
25 
26 int os_waiting_for_events(struct irq_fd *active_fds)
27 {
28 	struct irq_fd *irq_fd;
29 	int i, n, err;
30 
31 	n = poll(pollfds, pollfds_num, 0);
32 	if (n < 0) {
33 		err = -errno;
34 		if (errno != EINTR)
35 			printk("sigio_handler: os_waiting_for_events:"
36 			       " poll returned %d, errno = %d\n", n, errno);
37 		return err;
38 	}
39 
40 	if (n == 0)
41 		return 0;
42 
43 	irq_fd = active_fds;
44 
45 	for (i = 0; i < pollfds_num; i++) {
46 		if (pollfds[i].revents != 0) {
47 			irq_fd->current_events = pollfds[i].revents;
48 			pollfds[i].fd = -1;
49 		}
50 		irq_fd = irq_fd->next;
51 	}
52 	return n;
53 }
54 
55 int os_isatty(int fd)
56 {
57 	return isatty(fd);
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 	set_handler(SIGIO, SIG_IGN, 0, -1);
141 }
142 
143 void init_irq_signals(int on_sigstack)
144 {
145 	__sighandler_t h;
146 	int flags;
147 
148 	flags = on_sigstack ? SA_ONSTACK : 0;
149 	if (timer_irq_inited)
150 		h = (__sighandler_t)alarm_handler;
151 	else
152 		h = boot_timer_handler;
153 
154 	set_handler(SIGVTALRM, h, flags | SA_RESTART,
155 		    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, -1);
156 	set_handler(SIGIO, (__sighandler_t) sig_handler, flags | SA_RESTART,
157 		    SIGUSR1, SIGIO, SIGWINCH, SIGALRM, SIGVTALRM, -1);
158 	signal(SIGWINCH, SIG_IGN);
159 }
160