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uml: move SIGIO testing to sigio.c
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This patch narrows the sigio interface.  The boot-time SIGIO testing used to
be in start_up.c, which meant that pty_output_sigio and pty_close_sigio needed
to be global.  By moving that code here, those can become static and the
declarations moved from user_util.h.

os_check_bugs is also here because it only does the SIGIO checking.  If it
does more, it'll probably move back to start_up.c.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jeff Dike authored and Linus Torvalds committed May 7, 2007
1 parent c5e631c commit c65badb
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Showing 3 changed files with 145 additions and 148 deletions.
3 changes: 0 additions & 3 deletions arch/um/include/user_util.h
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Original file line number Diff line number Diff line change
Expand Up @@ -51,9 +51,6 @@ extern unsigned long _stext, _etext, _sdata, _edata, __bss_start, _end;
extern unsigned long _unprotected_end;
extern unsigned long brk_start;

extern int pty_output_sigio;
extern int pty_close_sigio;

extern void *add_signal_handler(int sig, void (*handler)(int));
extern int linux_main(int argc, char **argv);
extern void set_cmdline(char *cmd);
Expand Down
145 changes: 145 additions & 0 deletions arch/um/os-Linux/sigio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include <termios.h>
#include <pty.h>
#include <signal.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sched.h>
Expand All @@ -20,6 +21,7 @@
#include "sigio.h"
#include "os.h"
#include "um_malloc.h"
#include "init.h"

/* Protected by sigio_lock(), also used by sigio_cleanup, which is an
* exitcall.
Expand Down Expand Up @@ -320,6 +322,10 @@ static void write_sigio_workaround(void)
close(l_write_sigio_fds[1]);
}

/* Changed during early boot */
static int pty_output_sigio = 0;
static int pty_close_sigio = 0;

void maybe_sigio_broken(int fd, int read)
{
int err;
Expand Down Expand Up @@ -357,3 +363,142 @@ static void sigio_cleanup(void)
}

__uml_exitcall(sigio_cleanup);

/* 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 int async_pty(int master, int slave)
{
int flags;

flags = fcntl(master, F_GETFL);
if(flags < 0)
return -errno;

if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
(fcntl(master, F_SETOWN, os_getpid()) < 0))
return -errno;

if((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
return -errno;

return(0);
}

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 = async_pty(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);
}

/* Here because it only does the SIGIO testing for now */
void __init os_check_bugs(void)
{
check_sigio();
}
145 changes: 0 additions & 145 deletions arch/um/os-Linux/start_up.c
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Original file line number Diff line number Diff line change
Expand Up @@ -553,148 +553,3 @@ int __init parse_iomem(char *str, int *add)
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 int async_pty(int master, int slave)
{
int flags;

flags = fcntl(master, F_GETFL);
if(flags < 0)
return -errno;

if((fcntl(master, F_SETFL, flags | O_NONBLOCK | O_ASYNC) < 0) ||
(fcntl(master, F_SETOWN, os_getpid()) < 0))
return -errno;

if((fcntl(slave, F_SETFL, flags | O_NONBLOCK) < 0))
return -errno;

return(0);
}

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 = async_pty(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();
}

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