harddog_user.c
/*
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include "os.h"
#include "user.h"
struct dog_data {
int stdin;
int stdout;
int close_me[2];
};
static void pre_exec(void *d)
{
struct dog_data *data = d;
dup2(data->stdin, 0);
dup2(data->stdout, 1);
dup2(data->stdout, 2);
close(data->stdin);
close(data->stdout);
close(data->close_me[0]);
close(data->close_me[1]);
}
int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
{
struct dog_data data;
int in_fds[2], out_fds[2], pid, n, err;
char pid_buf[sizeof("nnnnn\0")], c;
char *pid_args[] = { "/usr/bin/uml_watchdog", "-pid", pid_buf, NULL };
char *mconsole_args[] = { "/usr/bin/uml_watchdog", "-mconsole", NULL,
NULL };
char **args = NULL;
err = os_pipe(in_fds, 1, 0);
if (err < 0) {
printk("harddog_open - os_pipe failed, err = %d\n", -err);
goto out;
}
err = os_pipe(out_fds, 1, 0);
if (err < 0) {
printk("harddog_open - os_pipe failed, err = %d\n", -err);
goto out_close_in;
}
data.stdin = out_fds[0];
data.stdout = in_fds[1];
data.close_me[0] = out_fds[1];
data.close_me[1] = in_fds[0];
if (sock != NULL) {
mconsole_args[2] = sock;
args = mconsole_args;
}
else {
/* XXX The os_getpid() is not SMP correct */
sprintf(pid_buf, "%d", os_getpid());
args = pid_args;
}
pid = run_helper(pre_exec, &data, args);
close(out_fds[0]);
close(in_fds[1]);
if (pid < 0) {
err = -pid;
printk("harddog_open - run_helper failed, errno = %d\n", -err);
goto out_close_out;
}
n = read(in_fds[0], &c, sizeof(c));
if (n == 0) {
printk("harddog_open - EOF on watchdog pipe\n");
helper_wait(pid);
err = -EIO;
goto out_close_out;
}
else if (n < 0) {
printk("harddog_open - read of watchdog pipe failed, "
"err = %d\n", errno);
helper_wait(pid);
err = n;
goto out_close_out;
}
*in_fd_ret = in_fds[0];
*out_fd_ret = out_fds[1];
return 0;
out_close_in:
close(in_fds[0]);
close(in_fds[1]);
out_close_out:
close(out_fds[0]);
close(out_fds[1]);
out:
return err;
}
void stop_watchdog(int in_fd, int out_fd)
{
close(in_fd);
close(out_fd);
}
int ping_watchdog(int fd)
{
int n;
char c = '\n';
n = write(fd, &c, sizeof(c));
if (n != sizeof(c)) {
printk("ping_watchdog - write failed, ret = %d, err = %d\n",
n, errno);
if (n < 0)
return n;
return -EIO;
}
return 1;
}