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-rw-r--r--arch/um/os-Linux/start_up.c128
1 files changed, 128 insertions, 0 deletions
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index 829d6b0d8b02..32753131f8d8 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -3,6 +3,7 @@
3 * Licensed under the GPL 3 * Licensed under the GPL
4 */ 4 */
5 5
6#include <pty.h>
6#include <stdio.h> 7#include <stdio.h>
7#include <stddef.h> 8#include <stddef.h>
8#include <stdarg.h> 9#include <stdarg.h>
@@ -539,3 +540,130 @@ int __init parse_iomem(char *str, int *add)
539 return(1); 540 return(1);
540} 541}
541 542
543
544/* Changed during early boot */
545int pty_output_sigio = 0;
546int pty_close_sigio = 0;
547
548/* Used as a flag during SIGIO testing early in boot */
549static volatile int got_sigio = 0;
550
551static void __init handler(int sig)
552{
553 got_sigio = 1;
554}
555
556struct openpty_arg {
557 int master;
558 int slave;
559 int err;
560};
561
562static 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
571static 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
617static 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
639static 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
651void __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
663void os_check_bugs(void)
664{
665 check_ptrace();
666 check_sigio();
667 check_devanon();
668}
669