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 int generic_console_write(int fd, const char *buf, int n, void *unused)
  25 {
  26         struct termios save, new;
  27         int err;
  28
  29         if(isatty(fd)){
  30                 CATCH_EINTR(err = tcgetattr(fd, &save));
  31                 if (err)
  32                         goto error;
  33                 new = save;
  34                 /* The terminal becomes a bit less raw, to handle \n also as
  35                  * "Carriage Return", not only as "New Line". Otherwise, the new
  36                  * line won't start at the first column.*/
  37                 new.c_oflag |= OPOST;
  38                 CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new));
  39                 if (err)
  40                         goto error;
  41         }
  42         err = generic_write(fd, buf, n, NULL);
  43         /* Restore raw mode, in any case; we *must* ignore any error apart
  44          * EINTR, except for debug.*/
  45         if(isatty(fd))
  46                 CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save));
  47         return(err);
  48 error:
  49         return(-errno);
  50 }
  51
  52 static void winch_handler(int sig)
  53 {
  54 }
  55
  56 struct winch_data {
  57         int pty_fd;
  58         int pipe_fd;
  59         int close_me;
  60 };
  61
  62 static int winch_thread(void *arg)
  63 {
  64         struct winch_data *data = arg;
  65         sigset_t sigs;
  66         int pty_fd, pipe_fd;
  67         int count, err;
  68         char c = 1;
  69
  70         os_close_file(data->close_me);
  71         pty_fd = data->pty_fd;
  72         pipe_fd = data->pipe_fd;
  73         count = os_write_file(pipe_fd, &c, sizeof(c));
  74         if(count != sizeof(c))
  75                 printk("winch_thread : failed to write synchronization "
  76                        "byte, err = %d\n", -count);
  77
  78         signal(SIGWINCH, winch_handler);
  79         sigfillset(&sigs);
  80         sigdelset(&sigs, SIGWINCH);
  81         if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){
  82                 printk("winch_thread : sigprocmask failed, errno = %d\n",
  83                        errno);
  84                 exit(1);
  85         }
  86
  87         if(setsid() < 0){
  88                 printk("winch_thread : setsid failed, errno = %d\n", errno);
  89                 exit(1);
  90         }
  91
  92         err = os_new_tty_pgrp(pty_fd, os_getpid());
  93         if(err < 0){
  94                 printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err);
  95                 exit(1);
  96         }
  97
  98         count = os_read_file(pipe_fd, &c, sizeof(c));
  99         if(count != sizeof(c))
 100                 printk("winch_thread : failed to read synchronization byte, "
 101                        "err = %d\n", -count);
 102
 103         while(1){
 104                 pause();
 105
 106                 count = os_write_file(pipe_fd, &c, sizeof(c));
 107                 if(count != sizeof(c))
 108                         printk("winch_thread : write failed, err = %d\n",
 109                                -count);
 110         }
 111 }
 112
 113 static int winch_tramp(int fd, void *device_data, int *fd_out)
 114 {
 115         struct winch_data data;
 116         unsigned long stack;
 117         int fds[2], pid, n, err;
 118         char c;
 119
 120         err = os_pipe(fds, 1, 1);
 121         if(err < 0){
 122                 printk("winch_tramp : os_pipe failed, err = %d\n", -err);
 123                 return(err);
 124         }
 125
 126         data = ((struct winch_data) { .pty_fd           = fd,
 127                                       .pipe_fd          = fds[1],
 128                                       .close_me         = fds[0] } );
 129         pid = run_helper_thread(winch_thread, &data, 0, &stack, 0);
 130         if(pid < 0){
 131                 printk("fork of winch_thread failed - errno = %d\n", errno);
 132                 return(pid);
 133         }
 134
 135         os_close_file(fds[1]);
 136         *fd_out = fds[0];
 137         n = os_read_file(fds[0], &c, sizeof(c));
 138         if(n != sizeof(c)){
 139                 printk("winch_tramp : failed to read synchronization byte\n");
 140                 printk("read failed, err = %d\n", -n);
 141                 printk("fd %d will not support SIGWINCH\n", fd);
 142                 *fd_out = -1;
 143         }
 144         return(pid);
 145 }
 146
 147 void register_winch(int fd, void *device_data)
 148 {
 149         int pid, thread, thread_fd;
 150         int count;
 151         char c = 1;
 152
 153         if(!isatty(fd))
 154                 return;
 155
 156         pid = tcgetpgrp(fd);
 157         if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd,
 158                              device_data) && (pid == -1)){
 159                 thread = winch_tramp(fd, device_data, &thread_fd);
 160                 if(fd != -1){
 161                         register_winch_irq(thread_fd, fd, thread, device_data);
 162
 163                         count = os_write_file(thread_fd, &c, sizeof(c));
 164                         if(count != sizeof(c))
 165                                 printk("register_winch : failed to write "
 166                                        "synchronization byte, err = %d\n",
 167                                         -count);
 168                 }
 169         }
 170 }
 171
 172 /*
 173  * Overrides for Emacs so that we follow Linus's tabbing style.
 174  * Emacs will notice this stuff at the end of the file and automatically
 175  * adjust the settings for this buffer only.  This must remain at the end
 176  * of the file.
 177  * ---------------------------------------------------------------------------
 178  * Local variables:
 179  * c-file-style: "linux"
 180  * End:
 181  */