Pull throttle into release branch
[linux-2.6] / arch / um / drivers / harddog_user.c
1 /*
2  * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include "user.h"
10 #include "mconsole.h"
11 #include "os.h"
12 #include "choose-mode.h"
13 #include "mode.h"
14
15 struct dog_data {
16         int stdin;
17         int stdout;
18         int close_me[2];
19 };
20
21 static void pre_exec(void *d)
22 {
23         struct dog_data *data = d;
24
25         dup2(data->stdin, 0);
26         dup2(data->stdout, 1);
27         dup2(data->stdout, 2);
28         os_close_file(data->stdin);
29         os_close_file(data->stdout);
30         os_close_file(data->close_me[0]);
31         os_close_file(data->close_me[1]);
32 }
33
34 int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
35 {
36         struct dog_data data;
37         int in_fds[2], out_fds[2], pid, n, err;
38         char pid_buf[sizeof("nnnnn\0")], c;
39         char *pid_args[] = { "/usr/bin/uml_watchdog", "-pid", pid_buf, NULL };
40         char *mconsole_args[] = { "/usr/bin/uml_watchdog", "-mconsole", NULL,
41                                   NULL };
42         char **args = NULL;
43
44         err = os_pipe(in_fds, 1, 0);
45         if(err < 0){
46                 printk("harddog_open - os_pipe failed, err = %d\n", -err);
47                 goto out;
48         }
49
50         err = os_pipe(out_fds, 1, 0);
51         if(err < 0){
52                 printk("harddog_open - os_pipe failed, err = %d\n", -err);
53                 goto out_close_in;
54         }
55
56         data.stdin = out_fds[0];
57         data.stdout = in_fds[1];
58         data.close_me[0] = out_fds[1];
59         data.close_me[1] = in_fds[0];
60
61         if(sock != NULL){
62                 mconsole_args[2] = sock;
63                 args = mconsole_args;
64         }
65         else {
66                 /* XXX The os_getpid() is not SMP correct */
67                 sprintf(pid_buf, "%d", CHOOSE_MODE(tracing_pid, os_getpid()));
68                 args = pid_args;
69         }
70
71         pid = run_helper(pre_exec, &data, args);
72
73         os_close_file(out_fds[0]);
74         os_close_file(in_fds[1]);
75
76         if(pid < 0){
77                 err = -pid;
78                 printk("harddog_open - run_helper failed, errno = %d\n", -err);
79                 goto out_close_out;
80         }
81
82         n = os_read_file(in_fds[0], &c, sizeof(c));
83         if(n == 0){
84                 printk("harddog_open - EOF on watchdog pipe\n");
85                 helper_wait(pid);
86                 err = -EIO;
87                 goto out_close_out;
88         }
89         else if(n < 0){
90                 printk("harddog_open - read of watchdog pipe failed, "
91                        "err = %d\n", -n);
92                 helper_wait(pid);
93                 err = n;
94                 goto out_close_out;
95         }
96         *in_fd_ret = in_fds[0];
97         *out_fd_ret = out_fds[1];
98         return 0;
99
100  out_close_in:
101         os_close_file(in_fds[0]);
102         os_close_file(in_fds[1]);
103  out_close_out:
104         os_close_file(out_fds[0]);
105         os_close_file(out_fds[1]);
106  out:
107         return err;
108 }
109
110 void stop_watchdog(int in_fd, int out_fd)
111 {
112         os_close_file(in_fd);
113         os_close_file(out_fd);
114 }
115
116 int ping_watchdog(int fd)
117 {
118         int n;
119         char c = '\n';
120
121         n = os_write_file(fd, &c, sizeof(c));
122         if(n != sizeof(c)){
123                 printk("ping_watchdog - write failed, err = %d\n", -n);
124                 if(n < 0)
125                         return n;
126                 return -EIO;
127         }
128         return 1;
129
130 }