Commit | Line | Data |
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1da177e4 LT |
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> | |
1d2ddcfb | 12 | #include <sched.h> |
1da177e4 LT |
13 | #include <sys/stat.h> |
14 | #include <sys/ioctl.h> | |
15 | #include <sys/socket.h> | |
16 | #include "kern_util.h" | |
1da177e4 LT |
17 | #include "chan_user.h" |
18 | #include "user.h" | |
1da177e4 LT |
19 | #include "os.h" |
20 | #include "choose-mode.h" | |
21 | #include "mode.h" | |
22 | ||
55c033c1 | 23 | int generic_console_write(int fd, const char *buf, int n) |
1da177e4 LT |
24 | { |
25 | struct termios save, new; | |
26 | int err; | |
27 | ||
28 | if(isatty(fd)){ | |
29 | CATCH_EINTR(err = tcgetattr(fd, &save)); | |
30 | if (err) | |
31 | goto error; | |
32 | new = save; | |
33 | /* The terminal becomes a bit less raw, to handle \n also as | |
34 | * "Carriage Return", not only as "New Line". Otherwise, the new | |
35 | * line won't start at the first column.*/ | |
36 | new.c_oflag |= OPOST; | |
37 | CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new)); | |
38 | if (err) | |
39 | goto error; | |
40 | } | |
41 | err = generic_write(fd, buf, n, NULL); | |
42 | /* Restore raw mode, in any case; we *must* ignore any error apart | |
43 | * EINTR, except for debug.*/ | |
44 | if(isatty(fd)) | |
45 | CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save)); | |
46 | return(err); | |
47 | error: | |
48 | return(-errno); | |
49 | } | |
50 | ||
51 | /* | |
52 | * UML SIGWINCH handling | |
53 | * | |
54 | * The point of this is to handle SIGWINCH on consoles which have host ttys and | |
55 | * relay them inside UML to whatever might be running on the console and cares | |
56 | * about the window size (since SIGWINCH notifies about terminal size changes). | |
57 | * | |
58 | * So, we have a separate thread for each host tty attached to a UML device | |
59 | * (side-issue - I'm annoyed that one thread can't have multiple controlling | |
60 | * ttys for purposed of handling SIGWINCH, but I imagine there are other reasons | |
61 | * that doesn't make any sense). | |
62 | * | |
63 | * SIGWINCH can't be received synchronously, so you have to set up to receive it | |
64 | * as a signal. That being the case, if you are going to wait for it, it is | |
ed1b58d8 | 65 | * convenient to sit in sigsuspend() and wait for the signal to bounce you out of |
1da177e4 LT |
66 | * it (see below for how we make sure to exit only on SIGWINCH). |
67 | */ | |
68 | ||
69 | static void winch_handler(int sig) | |
70 | { | |
71 | } | |
72 | ||
73 | struct winch_data { | |
74 | int pty_fd; | |
75 | int pipe_fd; | |
1da177e4 LT |
76 | }; |
77 | ||
78 | static int winch_thread(void *arg) | |
79 | { | |
80 | struct winch_data *data = arg; | |
81 | sigset_t sigs; | |
82 | int pty_fd, pipe_fd; | |
83 | int count, err; | |
84 | char c = 1; | |
85 | ||
1da177e4 LT |
86 | pty_fd = data->pty_fd; |
87 | pipe_fd = data->pipe_fd; | |
a6ea4cce | 88 | count = os_write_file(pipe_fd, &c, sizeof(c)); |
1da177e4 LT |
89 | if(count != sizeof(c)) |
90 | printk("winch_thread : failed to write synchronization " | |
91 | "byte, err = %d\n", -count); | |
92 | ||
93 | /* We are not using SIG_IGN on purpose, so don't fix it as I thought to | |
ed1b58d8 | 94 | * do! If using SIG_IGN, the sigsuspend() call below would not stop on |
1da177e4 LT |
95 | * SIGWINCH. */ |
96 | ||
97 | signal(SIGWINCH, winch_handler); | |
98 | sigfillset(&sigs); | |
ed1b58d8 | 99 | /* Block all signals possible. */ |
1da177e4 LT |
100 | if(sigprocmask(SIG_SETMASK, &sigs, NULL) < 0){ |
101 | printk("winch_thread : sigprocmask failed, errno = %d\n", | |
102 | errno); | |
103 | exit(1); | |
104 | } | |
ed1b58d8 BS |
105 | /* In sigsuspend(), block anything else than SIGWINCH. */ |
106 | sigdelset(&sigs, SIGWINCH); | |
1da177e4 LT |
107 | |
108 | if(setsid() < 0){ | |
109 | printk("winch_thread : setsid failed, errno = %d\n", errno); | |
110 | exit(1); | |
111 | } | |
112 | ||
113 | err = os_new_tty_pgrp(pty_fd, os_getpid()); | |
114 | if(err < 0){ | |
115 | printk("winch_thread : new_tty_pgrp failed, err = %d\n", -err); | |
116 | exit(1); | |
117 | } | |
118 | ||
119 | /* These are synchronization calls between various UML threads on the | |
120 | * host - since they are not different kernel threads, we cannot use | |
121 | * kernel semaphores. We don't use SysV semaphores because they are | |
03a67a46 | 122 | * persistent. */ |
a6ea4cce | 123 | count = os_read_file(pipe_fd, &c, sizeof(c)); |
1da177e4 LT |
124 | if(count != sizeof(c)) |
125 | printk("winch_thread : failed to read synchronization byte, " | |
126 | "err = %d\n", -count); | |
127 | ||
128 | while(1){ | |
129 | /* This will be interrupted by SIGWINCH only, since other signals | |
130 | * are blocked.*/ | |
ed1b58d8 | 131 | sigsuspend(&sigs); |
1da177e4 | 132 | |
a6ea4cce | 133 | count = os_write_file(pipe_fd, &c, sizeof(c)); |
1da177e4 LT |
134 | if(count != sizeof(c)) |
135 | printk("winch_thread : write failed, err = %d\n", | |
136 | -count); | |
137 | } | |
138 | } | |
139 | ||
140 | static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out) | |
141 | { | |
142 | struct winch_data data; | |
143 | unsigned long stack; | |
1f96ddb4 | 144 | int fds[2], n, err; |
1da177e4 LT |
145 | char c; |
146 | ||
147 | err = os_pipe(fds, 1, 1); | |
148 | if(err < 0){ | |
149 | printk("winch_tramp : os_pipe failed, err = %d\n", -err); | |
1f96ddb4 | 150 | goto out; |
1da177e4 LT |
151 | } |
152 | ||
153 | data = ((struct winch_data) { .pty_fd = fd, | |
1d2ddcfb JD |
154 | .pipe_fd = fds[1] } ); |
155 | /* CLONE_FILES so this thread doesn't hold open files which are open | |
156 | * now, but later closed. This is a problem with /dev/net/tun. | |
157 | */ | |
158 | err = run_helper_thread(winch_thread, &data, CLONE_FILES, &stack, 0); | |
1f96ddb4 | 159 | if(err < 0){ |
b16895b6 | 160 | printk("fork of winch_thread failed - errno = %d\n", -err); |
1f96ddb4 | 161 | goto out_close; |
1da177e4 LT |
162 | } |
163 | ||
1da177e4 | 164 | *fd_out = fds[0]; |
a6ea4cce | 165 | n = os_read_file(fds[0], &c, sizeof(c)); |
1da177e4 LT |
166 | if(n != sizeof(c)){ |
167 | printk("winch_tramp : failed to read synchronization byte\n"); | |
168 | printk("read failed, err = %d\n", -n); | |
169 | printk("fd %d will not support SIGWINCH\n", fd); | |
1f96ddb4 | 170 | err = -EINVAL; |
1d2ddcfb | 171 | goto out_close; |
1da177e4 | 172 | } |
1f96ddb4 JD |
173 | return err ; |
174 | ||
175 | out_close: | |
176 | os_close_file(fds[1]); | |
1f96ddb4 JD |
177 | os_close_file(fds[0]); |
178 | out: | |
179 | return err; | |
1da177e4 LT |
180 | } |
181 | ||
182 | void register_winch(int fd, struct tty_struct *tty) | |
183 | { | |
1f96ddb4 | 184 | int pid, thread, thread_fd = -1; |
1da177e4 LT |
185 | int count; |
186 | char c = 1; | |
187 | ||
188 | if(!isatty(fd)) | |
189 | return; | |
190 | ||
191 | pid = tcgetpgrp(fd); | |
192 | if(!CHOOSE_MODE_PROC(is_tracer_winch, is_skas_winch, pid, fd, | |
193 | tty) && (pid == -1)){ | |
194 | thread = winch_tramp(fd, tty, &thread_fd); | |
da00d9a5 | 195 | if(thread > 0){ |
1da177e4 LT |
196 | register_winch_irq(thread_fd, fd, thread, tty); |
197 | ||
a6ea4cce | 198 | count = os_write_file(thread_fd, &c, sizeof(c)); |
1da177e4 LT |
199 | if(count != sizeof(c)) |
200 | printk("register_winch : failed to write " | |
201 | "synchronization byte, err = %d\n", | |
202 | -count); | |
203 | } | |
204 | } | |
205 | } |