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, 1, NULL);
  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, 1, NULL);
  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 }