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