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 "helper.h"
  12 #include "mconsole.h"
  13 #include "os.h"
  14 #include "choose-mode.h"
  15 #include "mode.h"
  16
  17 struct dog_data {
  18         int stdin;
  19         int stdout;
  20         int close_me[2];
  21 };
  22
  23 static void pre_exec(void *d)
  24 {
  25         struct dog_data *data = d;
  26
  27         dup2(data->stdin, 0);
  28         dup2(data->stdout, 1);
  29         dup2(data->stdout, 2);
  30         close(data->stdin);
  31         close(data->stdout);
  32         close(data->close_me[0]);
  33         close(data->close_me[1]);
  34 }
  35
  36 int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock)
  37 {
  38         struct dog_data data;
  39         int in_fds[2], out_fds[2], pid, n, err;
  40         char pid_buf[sizeof("nnnnn\0")], c;
  41         char *pid_args[] = { "/usr/bin/uml_watchdog", "-pid", pid_buf, NULL };
  42         char *mconsole_args[] = { "/usr/bin/uml_watchdog", "-mconsole", NULL,
  43                                   NULL };
  44         char **args = NULL;
  45
  46         err = os_pipe(in_fds, 1, 0);
  47         if(err){
  48                 printk("harddog_open - os_pipe failed, errno = %d\n", -err);
  49                 return(err);
  50         }
  51
  52         err = os_pipe(out_fds, 1, 0);
  53         if(err){
  54                 printk("harddog_open - os_pipe failed, errno = %d\n", -err);
  55                 return(err);
  56         }
  57
  58         data.stdin = out_fds[0];
  59         data.stdout = in_fds[1];
  60         data.close_me[0] = out_fds[1];
  61         data.close_me[1] = in_fds[0];
  62
  63         if(sock != NULL){
  64                 mconsole_args[2] = sock;
  65                 args = mconsole_args;
  66         }
  67         else {
  68                 /* XXX The os_getpid() is not SMP correct */
  69                 sprintf(pid_buf, "%d", CHOOSE_MODE(tracing_pid, os_getpid()));
  70                 args = pid_args;
  71         }
  72
  73         pid = run_helper(pre_exec, &data, args, NULL);
  74
  75         close(out_fds[0]);
  76         close(in_fds[1]);
  77
  78         if(pid < 0){
  79                 err = -pid;
  80                 printk("harddog_open - run_helper failed, errno = %d\n", err);
  81                 goto out;
  82         }
  83
  84         n = read(in_fds[0], &c, sizeof(c));
  85         if(n == 0){
  86                 printk("harddog_open - EOF on watchdog pipe\n");
  87                 helper_wait(pid);
  88                 err = -EIO;
  89                 goto out;
  90         }
  91         else if(n < 0){
  92                 printk("harddog_open - read of watchdog pipe failed, "
  93                        "errno = %d\n", errno);
  94                 helper_wait(pid);
  95                 err = -errno;
  96                 goto out;
  97         }
  98         *in_fd_ret = in_fds[0];
  99         *out_fd_ret = out_fds[1];
 100         return(0);
 101  out:
 102         close(out_fds[1]);
 103         close(in_fds[0]);
 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, errno = %d\n",
 121                        errno);
 122                 return(-errno);
 123         }
 124         return 1;
 125
 126 }
 127
 128 /*
 129  * Overrides for Emacs so that we follow Linus's tabbing style.
 130  * Emacs will notice this stuff at the end of the file and automatically
 131  * adjust the settings for this buffer only.  This must remain at the end
 132  * of the file.
 133  * ---------------------------------------------------------------------------
 134  * Local variables:
 135  * c-file-style: "linux"
 136  * End:
 137  */