Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
[linux-2.6] / arch / um / drivers / harddog_user.c
1 /*
2  * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3  * Licensed under the GPL
4  */
5
6 #include <stdio.h>
7 #include <unistd.h>
8 #include <errno.h>
9 #include "os.h"
10 #include "user.h"
11
12 struct dog_data {
13         int stdin;
14         int stdout;
15         int close_me[2];
16 };
17
18 static void pre_exec(void *d)
19 {
20         struct dog_data *data = d;
21
22         dup2(data->stdin, 0);
23         dup2(data->stdout, 1);
24         dup2(data->stdout, 2);
25         close(data->stdin);
26         close(data->stdout);
27         close(data->close_me[0]);
28         close(data->close_me[1]);
29 }
30
31 int 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("nnnnn\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 = out_fds[0];
54         data.stdout = 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
107 void stop_watchdog(int in_fd, int out_fd)
108 {
109         close(in_fd);
110         close(out_fd);
111 }
112
113 int 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 }