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_util.h"
  10 #include "user.h"
  11 #include "mconsole.h"
  12 #include "os.h"
  13 #include "choose-mode.h"
  14 #include "mode.h"
  15
  16 struct dog_data {
  17         int stdin;
  18         int stdout;
  19         int close_me[2];
  20 };
  21
  22 static void pre_exec(void *d)
  23 {
  24         struct dog_data *data = d;
  25
  26         dup2(data->stdin, 0);
  27         dup2(data->stdout, 1);
  28         dup2(data->stdout, 2);
  29         os_close_file(data->stdin);
  30         os_close_file(data->stdout);
  31         os_close_file(data->close_me[0]);
  32         os_close_file(data->close_me[1]);
  33 }
  34
  35 int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
  36 {
  37         struct dog_data data;
  38         int in_fds[2], out_fds[2], pid, n, err;
  39         char pid_buf[sizeof("nnnnn\0")], c;
  40         char *pid_args[] = { "/usr/bin/uml_watchdog", "-pid", pid_buf, NULL };
  41         char *mconsole_args[] = { "/usr/bin/uml_watchdog", "-mconsole", NULL,
  42                                   NULL };
  43         char **args = NULL;
  44
  45         err = os_pipe(in_fds, 1, 0);
  46         if(err < 0){
  47                 printk("harddog_open - os_pipe failed, err = %d\n", -err);
  48                 goto out;
  49         }
  50
  51         err = os_pipe(out_fds, 1, 0);
  52         if(err < 0){
  53                 printk("harddog_open - os_pipe failed, err = %d\n", -err);
  54                 goto out_close_in;
  55         }
  56
  57         data.stdin = out_fds[0];
  58         data.stdout = in_fds[1];
  59         data.close_me[0] = out_fds[1];
  60         data.close_me[1] = in_fds[0];
  61
  62         if(sock != NULL){
  63                 mconsole_args[2] = sock;
  64                 args = mconsole_args;
  65         }
  66         else {
  67                 /* XXX The os_getpid() is not SMP correct */
  68                 sprintf(pid_buf, "%d", CHOOSE_MODE(tracing_pid, os_getpid()));
  69                 args = pid_args;
  70         }
  71
  72         pid = run_helper(pre_exec, &data, args, NULL);
  73
  74         os_close_file(out_fds[0]);
  75         os_close_file(in_fds[1]);
  76
  77         if(pid < 0){
  78                 err = -pid;
  79                 printk("harddog_open - run_helper failed, errno = %d\n", -err);
  80                 goto out_close_out;
  81         }
  82
  83         n = os_read_file(in_fds[0], &c, sizeof(c));
  84         if(n == 0){
  85                 printk("harddog_open - EOF on watchdog pipe\n");
  86                 helper_wait(pid);
  87                 err = -EIO;
  88                 goto out_close_out;
  89         }
  90         else if(n < 0){
  91                 printk("harddog_open - read of watchdog pipe failed, "
  92                        "err = %d\n", -n);
  93                 helper_wait(pid);
  94                 err = n;
  95                 goto out_close_out;
  96         }
  97         *in_fd_ret = in_fds[0];
  98         *out_fd_ret = out_fds[1];
  99         return 0;
 100
 101  out_close_in:
 102         os_close_file(in_fds[0]);
 103         os_close_file(in_fds[1]);
 104  out_close_out:
 105         os_close_file(out_fds[0]);
 106         os_close_file(out_fds[1]);
 107  out:
 108         return err;
 109 }
 110
 111 void stop_watchdog(int in_fd, int out_fd)
 112 {
 113         os_close_file(in_fd);
 114         os_close_file(out_fd);
 115 }
 116
 117 int ping_watchdog(int fd)
 118 {
 119         int n;
 120         char c = '\n';
 121
 122         n = os_write_file(fd, &c, sizeof(c));
 123         if(n != sizeof(c)){
 124                 printk("ping_watchdog - write failed, err = %d\n", -n);
 125                 if(n < 0)
 126                         return n;
 127                 return -EIO;
 128         }
 129         return 1;
 130
 131 }