[PATCH] uml: move SIGIO startup code to os-Linux/start_up.c

The serial UML OS-abstraction layer patch (um/kernel dir). This moves all startup code from sigio_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] uml: move SIGIO startup code to os-Linux/start_up.c
The serial UML OS-abstraction layer patch (um/kernel dir). This moves all startup code from sigio_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Jeff Dike · Linus Torvalds
1 parent 9b4f018d92
Showing 6 changed files with 148 additions and 157 deletions Side-by-side Diff
arch/um/include/os.h
arch/um/include/sigio.h
arch/um/kernel/sigio_kern.c
arch/um/kernel/sigio_user.c
arch/um/kernel/um_arch.c
arch/um/os-Linux/start_up.c
@@ -161,6 +161,7 @@
 /* start_up.c */
 extern void os_early_checks(void);
 extern int can_do_skas(void);
+extern void os_check_bugs(void);
  
 /* Make sure they are clear when running in TT mode. Required by
  * SEGV_MAYBE_FIXABLE */
@@ -8,7 +8,6 @@
  
 extern int write_sigio_irq(int fd);
 extern int register_sigio_fd(int fd);
-extern int read_sigio_fd(int fd);
 extern int add_sigio_fd(int fd, int read);
 extern int ignore_sigio_fd(int fd);
 extern void sigio_lock(void);
-/* 
+/*
  * Copyright (C) 2002 - 2003 Jeff Dike (jdike@addtoit.com)
  * Licensed under the GPL
  */
  
@@ -12,13 +12,16 @@
 #include "sigio.h"
 #include "irq_user.h"
 #include "irq_kern.h"
+#include "os.h"
  
 /* Protected by sigio_lock() called from write_sigio_workaround */
 static int sigio_irq_fd = -1;
  
 static irqreturn_t sigio_interrupt(int irq, void *data, struct pt_regs *unused)
 {
-	read_sigio_fd(sigio_irq_fd);
+	char c;
+
+	os_read_file(sigio_irq_fd, &c, sizeof(c));
 	reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
 	return(IRQ_HANDLED);
 }
@@ -50,6 +53,9 @@
 {
 	spin_unlock(&sigio_spinlock);
 }
+
+extern void sigio_cleanup(void);
+__uml_exitcall(sigio_cleanup);
  
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
-/* 
+/*
  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
  * Licensed under the GPL
  */
@@ -20,127 +20,6 @@
 #include "sigio.h"
 #include "os.h"
  
-/* Changed during early boot */
-int pty_output_sigio = 0;
-int pty_close_sigio = 0;
-
-/* Used as a flag during SIGIO testing early in boot */
-static volatile int got_sigio = 0;
-
-void __init handler(int sig)
-{
-	got_sigio = 1;
-}
-
-struct openpty_arg {
-	int master;
-	int slave;
-	int err;
-};
-
-static void openpty_cb(void *arg)
-{
-	struct openpty_arg *info = arg;
-
-	info->err = 0;
-	if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
-		info->err = -errno;
-}
-
-void __init check_one_sigio(void (*proc)(int, int))
-{
-	struct sigaction old, new;
-	struct openpty_arg pty = { .master = -1, .slave = -1 };
-	int master, slave, err;
-
-	initial_thread_cb(openpty_cb, &pty);
-	if(pty.err){
-		printk("openpty failed, errno = %d\n", -pty.err);
-		return;
-	}
-
-	master = pty.master;
-	slave = pty.slave;
-
-	if((master == -1) || (slave == -1)){
-		printk("openpty failed to allocate a pty\n");
-		return;
-	}
-
-	/* Not now, but complain so we now where we failed. */
-	err = raw(master);
-	if (err < 0)
-		panic("check_sigio : __raw failed, errno = %d\n", -err);
-
-	err = os_sigio_async(master, slave);
-	if(err < 0)
-		panic("tty_fds : sigio_async failed, err = %d\n", -err);
-
-	if(sigaction(SIGIO, NULL, &old) < 0)
-		panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
-	new = old;
-	new.sa_handler = handler;
-	if(sigaction(SIGIO, &new, NULL) < 0)
-		panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
-
-	got_sigio = 0;
-	(*proc)(master, slave);
-		
-	os_close_file(master);
-	os_close_file(slave);
-
-	if(sigaction(SIGIO, &old, NULL) < 0)
-		panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
-}
-
-static void tty_output(int master, int slave)
-{
-	int n;
-	char buf[512];
-
-	printk("Checking that host ptys support output SIGIO...");
-
-	memset(buf, 0, sizeof(buf));
-
-	while(os_write_file(master, buf, sizeof(buf)) > 0) ;
-	if(errno != EAGAIN)
-		panic("check_sigio : write failed, errno = %d\n", errno);
-	while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
-
-	if (got_sigio) {
-		printk("Yes\n");
-		pty_output_sigio = 1;
-	} else if (n == -EAGAIN) {
-		printk("No, enabling workaround\n");
-	} else {
-		panic("check_sigio : read failed, err = %d\n", n);
-	}
-}
-
-static void tty_close(int master, int slave)
-{
-	printk("Checking that host ptys support SIGIO on close...");
-
-	os_close_file(slave);
-	if(got_sigio){
-		printk("Yes\n");
-		pty_close_sigio = 1;
-	}
-	else printk("No, enabling workaround\n");
-}
-
-void __init check_sigio(void)
-{
-	if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
-	   (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
-		printk("No pseudo-terminals available - skipping pty SIGIO "
-		       "check\n");
-		return;
-	}
-	check_one_sigio(tty_output);
-	check_one_sigio(tty_close);
-}
-
 /* Protected by sigio_lock(), also used by sigio_cleanup, which is an 
  * exitcall.
  */
@@ -267,10 +146,10 @@
 	if(write_sigio_pid != -1) 
 		os_kill_process(write_sigio_pid, 1);
 	write_sigio_pid = -1;
-	os_close_file(sigio_private[0]);
-	os_close_file(sigio_private[1]);
-	os_close_file(write_sigio_fds[0]);
-	os_close_file(write_sigio_fds[1]);
+	close(sigio_private[0]);
+	close(sigio_private[1]);
+	close(write_sigio_fds[0]);
+	close(write_sigio_fds[1]);
 	/* Critical section end */
 	set_signals(flags);
 }
  
  
  
  
@@ -428,40 +307,19 @@
  out_free:
 	kfree(p);
  out_close2:
-	os_close_file(l_sigio_private[0]);
-	os_close_file(l_sigio_private[1]);
+	close(l_sigio_private[0]);
+	close(l_sigio_private[1]);
  out_close1:
-	os_close_file(l_write_sigio_fds[0]);
-	os_close_file(l_write_sigio_fds[1]);
+	close(l_write_sigio_fds[0]);
+	close(l_write_sigio_fds[1]);
 	return;
 }
  
-int read_sigio_fd(int fd)
+void sigio_cleanup(void)
 {
-	int n;
-	char c;
-
-	n = os_read_file(fd, &c, sizeof(c));
-	if(n != sizeof(c)){
-		if(n < 0) {
-			printk("read_sigio_fd - read failed, err = %d\n", -n);
-			return(n);
-		}
-		else {
-			printk("read_sigio_fd - short read, bytes = %d\n", n);
-			return(-EIO);
-		}
-	}
-	return(n);
-}
-
-static void sigio_cleanup(void)
-{
 	if (write_sigio_pid != -1) {
 		os_kill_process(write_sigio_pid, 1);
 		write_sigio_pid = -1;
 	}
 }
-
-__uml_exitcall(sigio_cleanup);
@@ -487,8 +487,7 @@
 void __init check_bugs(void)
 {
 	arch_check_bugs();
-	check_sigio();
-	check_devanon();
+ 	os_check_bugs();
 }
  
 void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
@@ -3,6 +3,7 @@
  * Licensed under the GPL
  */
  
+#include <pty.h>
 #include <stdio.h>
 #include <stddef.h>
 #include <stdarg.h>
@@ -537,5 +538,132 @@
 	os_close_file(fd);
  out:
 	return(1);
+}
+
+
+/* Changed during early boot */
+int pty_output_sigio = 0;
+int pty_close_sigio = 0;
+
+/* Used as a flag during SIGIO testing early in boot */
+static volatile int got_sigio = 0;
+
+static void __init handler(int sig)
+{
+	got_sigio = 1;
+}
+
+struct openpty_arg {
+	int master;
+	int slave;
+	int err;
+};
+
+static void openpty_cb(void *arg)
+{
+	struct openpty_arg *info = arg;
+
+	info->err = 0;
+	if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
+		info->err = -errno;
+}
+
+static void __init check_one_sigio(void (*proc)(int, int))
+{
+	struct sigaction old, new;
+	struct openpty_arg pty = { .master = -1, .slave = -1 };
+	int master, slave, err;
+
+	initial_thread_cb(openpty_cb, &pty);
+	if(pty.err){
+		printk("openpty failed, errno = %d\n", -pty.err);
+		return;
+	}
+
+	master = pty.master;
+	slave = pty.slave;
+
+	if((master == -1) || (slave == -1)){
+		printk("openpty failed to allocate a pty\n");
+		return;
+	}
+
+	/* Not now, but complain so we now where we failed. */
+	err = raw(master);
+	if (err < 0)
+		panic("check_sigio : __raw failed, errno = %d\n", -err);
+
+	err = os_sigio_async(master, slave);
+	if(err < 0)
+		panic("tty_fds : sigio_async failed, err = %d\n", -err);
+
+	if(sigaction(SIGIO, NULL, &old) < 0)
+		panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
+	new = old;
+	new.sa_handler = handler;
+	if(sigaction(SIGIO, &new, NULL) < 0)
+		panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
+
+	got_sigio = 0;
+	(*proc)(master, slave);
+
+	close(master);
+	close(slave);
+
+	if(sigaction(SIGIO, &old, NULL) < 0)
+		panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
+}
+
+static void tty_output(int master, int slave)
+{
+	int n;
+	char buf[512];
+
+	printk("Checking that host ptys support output SIGIO...");
+
+	memset(buf, 0, sizeof(buf));
+
+	while(os_write_file(master, buf, sizeof(buf)) > 0) ;
+	if(errno != EAGAIN)
+		panic("check_sigio : write failed, errno = %d\n", errno);
+	while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
+
+	if(got_sigio){
+		printk("Yes\n");
+		pty_output_sigio = 1;
+	}
+	else if(n == -EAGAIN) printk("No, enabling workaround\n");
+	else panic("check_sigio : read failed, err = %d\n", n);
+}
+
+static void tty_close(int master, int slave)
+{
+	printk("Checking that host ptys support SIGIO on close...");
+
+	close(slave);
+	if(got_sigio){
+		printk("Yes\n");
+		pty_close_sigio = 1;
+	}
+	else printk("No, enabling workaround\n");
+}
+
+void __init check_sigio(void)
+{
+	if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
+	   (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
+		printk("No pseudo-terminals available - skipping pty SIGIO "
+		       "check\n");
+		return;
+	}
+	check_one_sigio(tty_output);
+	check_one_sigio(tty_close);
+}
+
+void os_check_bugs(void)
+{
+	check_ptrace();
+	check_sigio();
+	check_devanon();
 }
...	...	@@ -161,6 +161,7 @@
161	161	/* start_up.c */
162	162	extern void os_early_checks(void);
163	163	extern int can_do_skas(void);
	164	+extern void os_check_bugs(void);
164	165
165	166	/* Make sure they are clear when running in TT mode. Required by
166	167	* SEGV_MAYBE_FIXABLE */
...	...	@@ -8,7 +8,6 @@
8	8
9	9	extern int write_sigio_irq(int fd);
10	10	extern int register_sigio_fd(int fd);
11		-extern int read_sigio_fd(int fd);
12	11	extern int add_sigio_fd(int fd, int read);
13	12	extern int ignore_sigio_fd(int fd);
14	13	extern void sigio_lock(void);
1		-/*
	1	+/*
2	2	* Copyright (C) 2002 - 2003 Jeff Dike (jdike@addtoit.com)
3	3	* Licensed under the GPL
4	4	*/
5	5
...	...	@@ -12,13 +12,16 @@
12	12	#include "sigio.h"
13	13	#include "irq_user.h"
14	14	#include "irq_kern.h"
	15	+#include "os.h"
15	16
16	17	/* Protected by sigio_lock() called from write_sigio_workaround */
17	18	static int sigio_irq_fd = -1;
18	19
19	20	static irqreturn_t sigio_interrupt(int irq, void data, struct pt_regs unused)
20	21	{
21		- read_sigio_fd(sigio_irq_fd);
	22	+ char c;
	23	+
	24	+ os_read_file(sigio_irq_fd, &c, sizeof(c));
22	25	reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
23	26	return(IRQ_HANDLED);
24	27	}
...	...	@@ -50,6 +53,9 @@
50	53	{
51	54	spin_unlock(&sigio_spinlock);
52	55	}
	56	+
	57	+extern void sigio_cleanup(void);
	58	+__uml_exitcall(sigio_cleanup);
53	59
54	60	/*
55	61	* Overrides for Emacs so that we follow Linus's tabbing style.
1		-/*
	1	+/*
2	2	* Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3	3	* Licensed under the GPL
4	4	*/
...	...	@@ -20,127 +20,6 @@
20	20	#include "sigio.h"
21	21	#include "os.h"
22	22
23		-/* Changed during early boot */
24		-int pty_output_sigio = 0;
25		-int pty_close_sigio = 0;
26		-
27		-/* Used as a flag during SIGIO testing early in boot */
28		-static volatile int got_sigio = 0;
29		-
30		-void __init handler(int sig)
31		-{
32		- got_sigio = 1;
33		-}
34		-
35		-struct openpty_arg {
36		- int master;
37		- int slave;
38		- int err;
39		-};
40		-
41		-static void openpty_cb(void *arg)
42		-{
43		- struct openpty_arg *info = arg;
44		-
45		- info->err = 0;
46		- if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
47		- info->err = -errno;
48		-}
49		-
50		-void __init check_one_sigio(void (*proc)(int, int))
51		-{
52		- struct sigaction old, new;
53		- struct openpty_arg pty = { .master = -1, .slave = -1 };
54		- int master, slave, err;
55		-
56		- initial_thread_cb(openpty_cb, &pty);
57		- if(pty.err){
58		- printk("openpty failed, errno = %d\n", -pty.err);
59		- return;
60		- }
61		-
62		- master = pty.master;
63		- slave = pty.slave;
64		-
65		- if((master == -1) \|\| (slave == -1)){
66		- printk("openpty failed to allocate a pty\n");
67		- return;
68		- }
69		-
70		- /* Not now, but complain so we now where we failed. */
71		- err = raw(master);
72		- if (err < 0)
73		- panic("check_sigio : __raw failed, errno = %d\n", -err);
74		-
75		- err = os_sigio_async(master, slave);
76		- if(err < 0)
77		- panic("tty_fds : sigio_async failed, err = %d\n", -err);
78		-
79		- if(sigaction(SIGIO, NULL, &old) < 0)
80		- panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
81		- new = old;
82		- new.sa_handler = handler;
83		- if(sigaction(SIGIO, &new, NULL) < 0)
84		- panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
85		-
86		- got_sigio = 0;
87		- (*proc)(master, slave);
88		-
89		- os_close_file(master);
90		- os_close_file(slave);
91		-
92		- if(sigaction(SIGIO, &old, NULL) < 0)
93		- panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
94		-}
95		-
96		-static void tty_output(int master, int slave)
97		-{
98		- int n;
99		- char buf[512];
100		-
101		- printk("Checking that host ptys support output SIGIO...");
102		-
103		- memset(buf, 0, sizeof(buf));
104		-
105		- while(os_write_file(master, buf, sizeof(buf)) > 0) ;
106		- if(errno != EAGAIN)
107		- panic("check_sigio : write failed, errno = %d\n", errno);
108		- while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
109		-
110		- if (got_sigio) {
111		- printk("Yes\n");
112		- pty_output_sigio = 1;
113		- } else if (n == -EAGAIN) {
114		- printk("No, enabling workaround\n");
115		- } else {
116		- panic("check_sigio : read failed, err = %d\n", n);
117		- }
118		-}
119		-
120		-static void tty_close(int master, int slave)
121		-{
122		- printk("Checking that host ptys support SIGIO on close...");
123		-
124		- os_close_file(slave);
125		- if(got_sigio){
126		- printk("Yes\n");
127		- pty_close_sigio = 1;
128		- }
129		- else printk("No, enabling workaround\n");
130		-}
131		-
132		-void __init check_sigio(void)
133		-{
134		- if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
135		- (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
136		- printk("No pseudo-terminals available - skipping pty SIGIO "
137		- "check\n");
138		- return;
139		- }
140		- check_one_sigio(tty_output);
141		- check_one_sigio(tty_close);
142		-}
143		-
144	23	/* Protected by sigio_lock(), also used by sigio_cleanup, which is an
145	24	* exitcall.
146	25	*/
...	...	@@ -267,10 +146,10 @@
267	146	if(write_sigio_pid != -1)
268	147	os_kill_process(write_sigio_pid, 1);
269	148	write_sigio_pid = -1;
270		- os_close_file(sigio_private[0]);
271		- os_close_file(sigio_private[1]);
272		- os_close_file(write_sigio_fds[0]);
273		- os_close_file(write_sigio_fds[1]);
	149	+ close(sigio_private[0]);
	150	+ close(sigio_private[1]);
	151	+ close(write_sigio_fds[0]);
	152	+ close(write_sigio_fds[1]);
274	153	/* Critical section end */
275	154	set_signals(flags);
276	155	}
277	156
278	157
279	158
280	159
...	...	@@ -428,40 +307,19 @@
428	307	out_free:
429	308	kfree(p);
430	309	out_close2:
431		- os_close_file(l_sigio_private[0]);
432		- os_close_file(l_sigio_private[1]);
	310	+ close(l_sigio_private[0]);
	311	+ close(l_sigio_private[1]);
433	312	out_close1:
434		- os_close_file(l_write_sigio_fds[0]);
435		- os_close_file(l_write_sigio_fds[1]);
	313	+ close(l_write_sigio_fds[0]);
	314	+ close(l_write_sigio_fds[1]);
436	315	return;
437	316	}
438	317
439		-int read_sigio_fd(int fd)
	318	+void sigio_cleanup(void)
440	319	{
441		- int n;
442		- char c;
443		-
444		- n = os_read_file(fd, &c, sizeof(c));
445		- if(n != sizeof(c)){
446		- if(n < 0) {
447		- printk("read_sigio_fd - read failed, err = %d\n", -n);
448		- return(n);
449		- }
450		- else {
451		- printk("read_sigio_fd - short read, bytes = %d\n", n);
452		- return(-EIO);
453		- }
454		- }
455		- return(n);
456		-}
457		-
458		-static void sigio_cleanup(void)
459		-{
460	320	if (write_sigio_pid != -1) {
461	321	os_kill_process(write_sigio_pid, 1);
462	322	write_sigio_pid = -1;
463	323	}
464	324	}
465		-
466		-__uml_exitcall(sigio_cleanup);
...	...	@@ -487,8 +487,7 @@
487	487	void __init check_bugs(void)
488	488	{
489	489	arch_check_bugs();
490		- check_sigio();
491		- check_devanon();
	490	+ os_check_bugs();
492	491	}
493	492
494	493	void apply_alternatives(struct alt_instr start, struct alt_instr end)
...	...	@@ -3,6 +3,7 @@
3	3	* Licensed under the GPL
4	4	*/
5	5
	6	+#include <pty.h>
6	7	#include <stdio.h>
7	8	#include <stddef.h>
8	9	#include <stdarg.h>
...	...	@@ -537,5 +538,132 @@
537	538	os_close_file(fd);
538	539	out:
539	540	return(1);
	541	+}
	542	+
	543	+
	544	+/* Changed during early boot */
	545	+int pty_output_sigio = 0;
	546	+int pty_close_sigio = 0;
	547	+
	548	+/* Used as a flag during SIGIO testing early in boot */
	549	+static volatile int got_sigio = 0;
	550	+
	551	+static void __init handler(int sig)
	552	+{
	553	+ got_sigio = 1;
	554	+}
	555	+
	556	+struct openpty_arg {
	557	+ int master;
	558	+ int slave;
	559	+ int err;
	560	+};
	561	+
	562	+static void openpty_cb(void *arg)
	563	+{
	564	+ struct openpty_arg *info = arg;
	565	+
	566	+ info->err = 0;
	567	+ if(openpty(&info->master, &info->slave, NULL, NULL, NULL))
	568	+ info->err = -errno;
	569	+}
	570	+
	571	+static void __init check_one_sigio(void (*proc)(int, int))
	572	+{
	573	+ struct sigaction old, new;
	574	+ struct openpty_arg pty = { .master = -1, .slave = -1 };
	575	+ int master, slave, err;
	576	+
	577	+ initial_thread_cb(openpty_cb, &pty);
	578	+ if(pty.err){
	579	+ printk("openpty failed, errno = %d\n", -pty.err);
	580	+ return;
	581	+ }
	582	+
	583	+ master = pty.master;
	584	+ slave = pty.slave;
	585	+
	586	+ if((master == -1) \|\| (slave == -1)){
	587	+ printk("openpty failed to allocate a pty\n");
	588	+ return;
	589	+ }
	590	+
	591	+ /* Not now, but complain so we now where we failed. */
	592	+ err = raw(master);
	593	+ if (err < 0)
	594	+ panic("check_sigio : __raw failed, errno = %d\n", -err);
	595	+
	596	+ err = os_sigio_async(master, slave);
	597	+ if(err < 0)
	598	+ panic("tty_fds : sigio_async failed, err = %d\n", -err);
	599	+
	600	+ if(sigaction(SIGIO, NULL, &old) < 0)
	601	+ panic("check_sigio : sigaction 1 failed, errno = %d\n", errno);
	602	+ new = old;
	603	+ new.sa_handler = handler;
	604	+ if(sigaction(SIGIO, &new, NULL) < 0)
	605	+ panic("check_sigio : sigaction 2 failed, errno = %d\n", errno);
	606	+
	607	+ got_sigio = 0;
	608	+ (*proc)(master, slave);
	609	+
	610	+ close(master);
	611	+ close(slave);
	612	+
	613	+ if(sigaction(SIGIO, &old, NULL) < 0)
	614	+ panic("check_sigio : sigaction 3 failed, errno = %d\n", errno);
	615	+}
	616	+
	617	+static void tty_output(int master, int slave)
	618	+{
	619	+ int n;
	620	+ char buf[512];
	621	+
	622	+ printk("Checking that host ptys support output SIGIO...");
	623	+
	624	+ memset(buf, 0, sizeof(buf));
	625	+
	626	+ while(os_write_file(master, buf, sizeof(buf)) > 0) ;
	627	+ if(errno != EAGAIN)
	628	+ panic("check_sigio : write failed, errno = %d\n", errno);
	629	+ while(((n = os_read_file(slave, buf, sizeof(buf))) > 0) && !got_sigio) ;
	630	+
	631	+ if(got_sigio){
	632	+ printk("Yes\n");
	633	+ pty_output_sigio = 1;
	634	+ }
	635	+ else if(n == -EAGAIN) printk("No, enabling workaround\n");
	636	+ else panic("check_sigio : read failed, err = %d\n", n);
	637	+}
	638	+
	639	+static void tty_close(int master, int slave)
	640	+{
	641	+ printk("Checking that host ptys support SIGIO on close...");
	642	+
	643	+ close(slave);
	644	+ if(got_sigio){
	645	+ printk("Yes\n");
	646	+ pty_close_sigio = 1;
	647	+ }
	648	+ else printk("No, enabling workaround\n");
	649	+}
	650	+
	651	+void __init check_sigio(void)
	652	+{
	653	+ if((os_access("/dev/ptmx", OS_ACC_R_OK) < 0) &&
	654	+ (os_access("/dev/ptyp0", OS_ACC_R_OK) < 0)){
	655	+ printk("No pseudo-terminals available - skipping pty SIGIO "
	656	+ "check\n");
	657	+ return;
	658	+ }
	659	+ check_one_sigio(tty_output);
	660	+ check_one_sigio(tty_close);
	661	+}
	662	+
	663	+void os_check_bugs(void)
	664	+{
	665	+ check_ptrace();
	666	+ check_sigio();
	667	+ check_devanon();
540	668	}