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 }