arch/um/drivers/chan_user.c

   1 /*
   2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <unistd.h>
   7 #include <stdlib.h>
   8 #include <errno.h>
   9 #include <termios.h>
  10 #include <string.h>
  11 #include <signal.h>
  12 #include <sys/stat.h>
  13 #include <sys/ioctl.h>
  14 #include <sys/socket.h>
  15 #include "kern_util.h"
  16 #include "user_util.h"
  17 #include "chan_user.h"
  18 #include "user.h"
  19 #include "helper.h"
  20 #include "os.h"
  21 #include "choose-mode.h"
  22 #include "mode.h"
  23
  24 static void winch_handler(int sig)
  25 {
  26 }
  27
  28 struct winch_data {
  29         int pty_fd;
  30         int pipe_fd;
  31         int close_me;
  32 };
  33
  34 /* XXX This breaks horribly (by hanging UML) when moved to chan_kern.c -
  35  * needs investigation
  36  */
  37 int generic_console_write(int fd, const char *buf, int n, void *unused)
  38 {
  39         struct termios save, new;
  40         int err;
  41
  42         if(isatty(fd)){
  43                 tcgetattr(fd, &save);
  44                 new = save;
  45                 new.c_oflag |= OPOST;
  46                 tcsetattr(fd, TCSAFLUSH, &new);
  47         }
  48         err = generic_write(fd, buf, n, NULL);
  49         if(isatty(fd)) tcsetattr(fd, TCSAFLUSH, &save);
  50         return(err);
  51 }
  52
  53 static int winch_thread(void *arg)
  54 {
  55         struct winch_data *data = arg;
  56         sigset_t sigs;
  57         int pty_fd, pipe_fd;
  58         int count, err;
  59         char c = 1;
  60
  61         os_close_file(data->close_me);
  62         pty_fd = data->pty_fd;
  63         pipe_fd = data->pipe_fd;
  64         count = os_write_file(pipe_fd, &c, sizeof(c));
  65         if(count != sizeof(c))
  66                 printk("winch_thread : failed to write synchronization "
  67                        "byte, err = %d\n", -count);
  68
  69         signal(SIGWINCH, winch_handler);
  70         sigfillset(&sigs);
  71         sigdelset(&sigs, SIGWINCH);
  72         if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
  73                 printk("winch_thread : sigprocmask failed, errno = %d\n",
  74                        errno);
  75                 exit(1);
  76         }
  77
  78         if(setsid() < 0){
  79                 printk("winch_thread : setsid failed, errno = %d\n", errno);
  80                 exit(1);
  81         }
  82
  83         err = os_new_tty_pgrp(pty_fd, os_getpid());
  84         if(err < 0){
  85                 printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err);
  86                 exit(1);
  87         }
  88
  89         count = os_read_file(pipe_fd, &c, sizeof(c));
  90         if(count != sizeof(c))
  91                 printk("winch_thread : failed to read synchronization byte, "
  92                        "err = %d\n", -count);
  93
  94         while(1){
  95                 pause();
  96
  97                 count = os_write_file(pipe_fd, &c, sizeof(c));
  98                 if(count != sizeof(c))
  99                         printk("winch_thread : write failed, err = %d\n",
 100                                -count);
 101         }
 102 }
 103
 104 static int winch_tramp(int fd, void *device_data, int *fd_out)
 105 {
 106         struct winch_data data;
 107         unsigned long stack;
 108         int fds[2], pid, n, err;
 109         char c;
 110
 111         err = os_pipe(fds, 1, 1);
 112         if(err < 0){
 113                 printk("winch_tramp : os_pipe failed, err = %d\n", -err);
 114                 return(err);
 115         }
 116
 117         data = ((struct winch_data) { .pty_fd           = fd,
 118                                       .pipe_fd          = fds[1],
 119                                       .close_me         = fds[0] } );
 120         pid = run_helper_thread(winch_thread, &data, 0, &stack, 0);
 121         if(pid < 0){
 122                 printk("fork of winch_thread failed - errno = %d\n", errno);
 123                 return(pid);
 124         }
 125
 126         os_close_file(fds[1]);
 127         *fd_out = fds[0];
 128         n = os_read_file(fds[0], &c, sizeof(c));
 129         if(n != sizeof(c)){
 130                 printk("winch_tramp : failed to read synchronization byte\n");
 131                 printk("read failed, err = %d\n", -n);
 132                 printk("fd %d will not support SIGWINCH\n", fd);
 133                 *fd_out = -1;
 134         }
 135         return(pid);
 136 }
 137
 138 void register_winch(int fd, void *device_data)
 139 {
 140         int pid, thread, thread_fd;
 141         int count;
 142         char c = 1;
 143
 144         if(!isatty(fd))
 145                 return;
 146
 147         pid = tcgetpgrp(fd);
 148         if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd,
 149                              device_data) && (pid == -1)){
 150                 thread = winch_tramp(fd, device_data, &thread_fd);
 151                 if(fd != -1){
 152                         register_winch_irq(thread_fd, fd, thread, device_data);
 153
 154                         count = os_write_file(thread_fd, &c, sizeof(c));
 155                         if(count != sizeof(c))
 156                                 printk("register_winch : failed to write "
 157                                        "synchronization byte, err = %d\n",
 158                                         -count);
 159                 }
 160         }
 161 }
 162
 163 /*
 164  * Overrides for Emacs so that we follow Linus's tabbing style.
 165  * Emacs will notice this stuff at the end of the file and automatically
 166  * adjust the settings for this buffer only.  This must remain at the end
 167  * of the file.
 168  * ---------------------------------------------------------------------------
 169  * Local variables:
 170  * c-file-style: "linux"
 171  * End:
 172  */