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 /* 53 * UML SIGWINCH handling 54 * 55 * The point of this is to handle SIGWINCH on consoles which have host ttys and 56 * relay them inside UML to whatever might be running on the console and cares 57 * about the window size (since SIGWINCH notifies about terminal size changes). 58 * 59 * So, we have a separate thread for each host tty attached to a UML device 60 * (side-issue - I'm annoyed that one thread can't have multiple controlling 61 * ttys for purposed of handling SIGWINCH, but I imagine there are other reasons 62 * that doesn't make any sense). 63 * 64 * SIGWINCH can't be received synchronously, so you have to set up to receive it 65 * as a signal. That being the case, if you are going to wait for it, it is 66 * convenient to sit in a pause() and wait for the signal to bounce you out of 67 * it (see below for how we make sure to exit only on SIGWINCH). 68 */ 69 70 static void winch_handler(int sig) 71 { 72 } 73 74 struct winch_data { 75 int pty_fd; 76 int pipe_fd; 77 int close_me; 78 }; 79 80 static int winch_thread(void *arg) 81 { 82 struct winch_data *data = arg; 83 sigset_t sigs; 84 int pty_fd, pipe_fd; 85 int count, err; 86 char c = 1; 87 88 os_close_file(data->close_me); 89 pty_fd = data->pty_fd; 90 pipe_fd = data->pipe_fd; 91 count = os_write_file(pipe_fd, &c, sizeof(c)); 92 if(count != sizeof(c)) 93 printk("winch_thread : failed to write synchronization " 94 "byte, err = %d\n", -count); 95 96 /* We are not using SIG_IGN on purpose, so don't fix it as I thought to 97 * do! If using SIG_IGN, the pause() call below would not stop on 98 * SIGWINCH. */ 99 100 signal(SIGWINCH, winch_handler); 101 sigfillset(&sigs); 102 sigdelset(&sigs, SIGWINCH); 103 /* Block anything else than SIGWINCH. */ 104 if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){ 105 printk("winch_thread : sigprocmask failed, errno = %d\n", 106 errno); 107 exit(1); 108 } 109 110 if(setsid() < 0){ 111 printk("winch_thread : setsid failed, errno = %d\n", errno); 112 exit(1); 113 } 114 115 err = os_new_tty_pgrp(pty_fd, os_getpid()); 116 if(err < 0){ 117 printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err); 118 exit(1); 119 } 120 121 /* These are synchronization calls between various UML threads on the 122 * host - since they are not different kernel threads, we cannot use 123 * kernel semaphores. We don't use SysV semaphores because they are 124 * persistant. */ 125 count = os_read_file(pipe_fd, &c, sizeof(c)); 126 if(count != sizeof(c)) 127 printk("winch_thread : failed to read synchronization byte, " 128 "err = %d\n", -count); 129 130 while(1){ 131 /* This will be interrupted by SIGWINCH only, since other signals 132 * are blocked.*/ 133 pause(); 134 135 count = os_write_file(pipe_fd, &c, sizeof(c)); 136 if(count != sizeof(c)) 137 printk("winch_thread : write failed, err = %d\n", 138 -count); 139 } 140 } 141 142 static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out) 143 { 144 struct winch_data data; 145 unsigned long stack; 146 int fds[2], pid, n, err; 147 char c; 148 149 err = os_pipe(fds, 1, 1); 150 if(err < 0){ 151 printk("winch_tramp : os_pipe failed, err = %d\n", -err); 152 return(err); 153 } 154 155 data = ((struct winch_data) { .pty_fd = fd, 156 .pipe_fd = fds[1], 157 .close_me = fds[0] } ); 158 pid = run_helper_thread(winch_thread, &data, 0, &stack, 0); 159 if(pid < 0){ 160 printk("fork of winch_thread failed - errno = %d\n", errno); 161 return(pid); 162 } 163 164 os_close_file(fds[1]); 165 *fd_out = fds[0]; 166 n = os_read_file(fds[0], &c, sizeof(c)); 167 if(n != sizeof(c)){ 168 printk("winch_tramp : failed to read synchronization byte\n"); 169 printk("read failed, err = %d\n", -n); 170 printk("fd %d will not support SIGWINCH\n", fd); 171 *fd_out = -1; 172 } 173 return(pid); 174 } 175 176 void register_winch(int fd, struct tty_struct *tty) 177 { 178 int pid, thread, thread_fd; 179 int count; 180 char c = 1; 181 182 if(!isatty(fd)) 183 return; 184 185 pid = tcgetpgrp(fd); 186 if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd, 187 tty) && (pid == -1)){ 188 thread = winch_tramp(fd, tty, &thread_fd); 189 if(fd != -1){ 190 register_winch_irq(thread_fd, fd, thread, tty); 191 192 count = os_write_file(thread_fd, &c, sizeof(c)); 193 if(count != sizeof(c)) 194 printk("register_winch : failed to write " 195 "synchronization byte, err = %d\n", 196 -count); 197 } 198 } 199 } 200 201 /* 202 * Overrides for Emacs so that we follow Linus's tabbing style. 203 * Emacs will notice this stuff at the end of the file and automatically 204 * adjust the settings for this buffer only. This must remain at the end 205 * of the file. 206 * --------------------------------------------------------------------------- 207 * Local variables: 208 * c-file-style: "linux" 209 * End: 210 */ 211