Linux Kernel  3.7.1
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harddog_user.c
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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 
11 struct dog_data {
12  int stdin;
13  int stdout;
14  int close_me[2];
15 };
16 
17 static void pre_exec(void *d)
18 {
19  struct dog_data *data = d;
20 
21  dup2(data->stdin, 0);
22  dup2(data->stdout, 1);
23  dup2(data->stdout, 2);
24  close(data->stdin);
25  close(data->stdout);
26  close(data->close_me[0]);
27  close(data->close_me[1]);
28 }
29 
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 = out_fds[0];
53  data.stdout = 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 
106 void stop_watchdog(int in_fd, int out_fd)
107 {
108  close(in_fd);
109  close(out_fd);
110 }
111 
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 }