1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 */
5
6#include <stdio.h>
7#include <unistd.h>
8#include <errno.h>
9#include <os.h>
10#include "harddog.h"
11
12struct dog_data {
13	int stdin_fd;
14	int stdout_fd;
15	int close_me[2];
16};
17
18static void pre_exec(void *d)
19{
20	struct dog_data *data = d;
21
22	dup2(data->stdin_fd, 0);
23	dup2(data->stdout_fd, 1);
24	dup2(data->stdout_fd, 2);
25	close(data->stdin_fd);
26	close(data->stdout_fd);
27	close(data->close_me[0]);
28	close(data->close_me[1]);
29}
30
31int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
32{
33	struct dog_data data;
34	int in_fds[2], out_fds[2], pid, n, err;
35	char pid_buf[sizeof("nnnnnnn\0")], c;
36	char *pid_args[] = { "/usr/bin/uml_watchdog", "-pid", pid_buf, NULL };
37	char *mconsole_args[] = { "/usr/bin/uml_watchdog", "-mconsole", NULL,
38				  NULL };
39	char **args = NULL;
40
41	err = os_pipe(in_fds, 1, 0);
42	if (err < 0) {
43		printk("harddog_open - os_pipe failed, err = %d\n", -err);
44		goto out;
45	}
46
47	err = os_pipe(out_fds, 1, 0);
48	if (err < 0) {
49		printk("harddog_open - os_pipe failed, err = %d\n", -err);
50		goto out_close_in;
51	}
52
53	data.stdin_fd = out_fds[0];
54	data.stdout_fd = in_fds[1];
55	data.close_me[0] = out_fds[1];
56	data.close_me[1] = in_fds[0];
57
58	if (sock != NULL) {
59		mconsole_args[2] = sock;
60		args = mconsole_args;
61	}
62	else {
63		/* XXX The os_getpid() is not SMP correct */
64		sprintf(pid_buf, "%d", os_getpid());
65		args = pid_args;
66	}
67
68	pid = run_helper(pre_exec, &data, args);
69
70	close(out_fds[0]);
71	close(in_fds[1]);
72
73	if (pid < 0) {
74		err = -pid;
75		printk("harddog_open - run_helper failed, errno = %d\n", -err);
76		goto out_close_out;
77	}
78
79	n = read(in_fds[0], &c, sizeof(c));
80	if (n == 0) {
81		printk("harddog_open - EOF on watchdog pipe\n");
82		helper_wait(pid);
83		err = -EIO;
84		goto out_close_out;
85	}
86	else if (n < 0) {
87		printk("harddog_open - read of watchdog pipe failed, "
88		       "err = %d\n", errno);
89		helper_wait(pid);
90		err = n;
91		goto out_close_out;
92	}
93	*in_fd_ret = in_fds[0];
94	*out_fd_ret = out_fds[1];
95	return 0;
96
97 out_close_in:
98	close(in_fds[0]);
99	close(in_fds[1]);
100 out_close_out:
101	close(out_fds[0]);
102	close(out_fds[1]);
103 out:
104	return err;
105}
106
107void stop_watchdog(int in_fd, int out_fd)
108{
109	close(in_fd);
110	close(out_fd);
111}
112
113int ping_watchdog(int fd)
114{
115	int n;
116	char c = '\n';
117
118	n = write(fd, &c, sizeof(c));
119	if (n != sizeof(c)) {
120		printk("ping_watchdog - write failed, ret = %d, err = %d\n",
121		       n, errno);
122		if (n < 0)
123			return n;
124		return -EIO;
125	}
126	return 1;
127
128}
129