Commit | Line | Data |
---|---|---|
cb8fa61c | 1 | /* |
e99525f9 | 2 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
1da177e4 | 6 | #include <stdlib.h> |
e99525f9 | 7 | #include <unistd.h> |
1da177e4 | 8 | #include <errno.h> |
1d2ddcfb | 9 | #include <sched.h> |
e99525f9 JD |
10 | #include <signal.h> |
11 | #include <termios.h> | |
1da177e4 | 12 | #include <sys/ioctl.h> |
1da177e4 | 13 | #include "chan_user.h" |
1da177e4 | 14 | #include "os.h" |
89fe6476 | 15 | #include "um_malloc.h" |
e99525f9 | 16 | #include "user.h" |
89fe6476 JD |
17 | |
18 | void generic_close(int fd, void *unused) | |
19 | { | |
8e2d10e1 | 20 | close(fd); |
89fe6476 JD |
21 | } |
22 | ||
23 | int generic_read(int fd, char *c_out, void *unused) | |
24 | { | |
25 | int n; | |
26 | ||
8e2d10e1 JD |
27 | n = read(fd, c_out, sizeof(*c_out)); |
28 | if (n > 0) | |
29 | return n; | |
30 | else if (errno == EAGAIN) | |
89fe6476 | 31 | return 0; |
8e2d10e1 | 32 | else if (n == 0) |
89fe6476 | 33 | return -EIO; |
8e2d10e1 | 34 | return -errno; |
89fe6476 JD |
35 | } |
36 | ||
8e2d10e1 | 37 | /* XXX Trivial wrapper around write */ |
89fe6476 JD |
38 | |
39 | int generic_write(int fd, const char *buf, int n, void *unused) | |
40 | { | |
c59dbcad JD |
41 | int err; |
42 | ||
43 | err = write(fd, buf, n); | |
44 | if (err > 0) | |
45 | return err; | |
46 | else if (errno == EAGAIN) | |
47 | return 0; | |
48 | else if (err == 0) | |
49 | return -EIO; | |
50 | return -errno; | |
89fe6476 JD |
51 | } |
52 | ||
53 | int generic_window_size(int fd, void *unused, unsigned short *rows_out, | |
54 | unsigned short *cols_out) | |
55 | { | |
8e2d10e1 | 56 | struct winsize size; |
89fe6476 JD |
57 | int ret; |
58 | ||
e99525f9 | 59 | if (ioctl(fd, TIOCGWINSZ, &size) < 0) |
8e2d10e1 | 60 | return -errno; |
89fe6476 | 61 | |
8e2d10e1 | 62 | ret = ((*rows_out != size.ws_row) || (*cols_out != size.ws_col)); |
89fe6476 | 63 | |
8e2d10e1 JD |
64 | *rows_out = size.ws_row; |
65 | *cols_out = size.ws_col; | |
89fe6476 JD |
66 | |
67 | return ret; | |
68 | } | |
69 | ||
70 | void generic_free(void *data) | |
71 | { | |
72 | kfree(data); | |
73 | } | |
1da177e4 | 74 | |
55c033c1 | 75 | int generic_console_write(int fd, const char *buf, int n) |
1da177e4 LT |
76 | { |
77 | struct termios save, new; | |
78 | int err; | |
79 | ||
e99525f9 | 80 | if (isatty(fd)) { |
1da177e4 LT |
81 | CATCH_EINTR(err = tcgetattr(fd, &save)); |
82 | if (err) | |
83 | goto error; | |
84 | new = save; | |
cb8fa61c JD |
85 | /* |
86 | * The terminal becomes a bit less raw, to handle \n also as | |
1da177e4 | 87 | * "Carriage Return", not only as "New Line". Otherwise, the new |
cb8fa61c JD |
88 | * line won't start at the first column. |
89 | */ | |
1da177e4 LT |
90 | new.c_oflag |= OPOST; |
91 | CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new)); | |
92 | if (err) | |
93 | goto error; | |
94 | } | |
95 | err = generic_write(fd, buf, n, NULL); | |
cb8fa61c JD |
96 | /* |
97 | * Restore raw mode, in any case; we *must* ignore any error apart | |
98 | * EINTR, except for debug. | |
99 | */ | |
e99525f9 | 100 | if (isatty(fd)) |
1da177e4 | 101 | CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save)); |
e99525f9 | 102 | return err; |
1da177e4 | 103 | error: |
e99525f9 | 104 | return -errno; |
1da177e4 LT |
105 | } |
106 | ||
107 | /* | |
108 | * UML SIGWINCH handling | |
109 | * | |
42a359e3 JD |
110 | * The point of this is to handle SIGWINCH on consoles which have host |
111 | * ttys and relay them inside UML to whatever might be running on the | |
112 | * console and cares about the window size (since SIGWINCH notifies | |
113 | * about terminal size changes). | |
1da177e4 | 114 | * |
42a359e3 JD |
115 | * So, we have a separate thread for each host tty attached to a UML |
116 | * device (side-issue - I'm annoyed that one thread can't have | |
117 | * multiple controlling ttys for the purpose of handling SIGWINCH, but | |
118 | * I imagine there are other reasons that doesn't make any sense). | |
1da177e4 | 119 | * |
42a359e3 JD |
120 | * SIGWINCH can't be received synchronously, so you have to set up to |
121 | * receive it as a signal. That being the case, if you are going to | |
122 | * wait for it, it is convenient to sit in sigsuspend() and wait for | |
123 | * the signal to bounce you out of it (see below for how we make sure | |
124 | * to exit only on SIGWINCH). | |
1da177e4 LT |
125 | */ |
126 | ||
127 | static void winch_handler(int sig) | |
128 | { | |
129 | } | |
130 | ||
131 | struct winch_data { | |
132 | int pty_fd; | |
133 | int pipe_fd; | |
1da177e4 LT |
134 | }; |
135 | ||
136 | static int winch_thread(void *arg) | |
137 | { | |
138 | struct winch_data *data = arg; | |
139 | sigset_t sigs; | |
140 | int pty_fd, pipe_fd; | |
8ca842c4 | 141 | int count; |
1da177e4 LT |
142 | char c = 1; |
143 | ||
1da177e4 LT |
144 | pty_fd = data->pty_fd; |
145 | pipe_fd = data->pipe_fd; | |
8ca842c4 | 146 | count = write(pipe_fd, &c, sizeof(c)); |
e99525f9 JD |
147 | if (count != sizeof(c)) |
148 | printk(UM_KERN_ERR "winch_thread : failed to write " | |
149 | "synchronization byte, err = %d\n", -count); | |
1da177e4 | 150 | |
e99525f9 JD |
151 | /* |
152 | * We are not using SIG_IGN on purpose, so don't fix it as I thought to | |
ed1b58d8 | 153 | * do! If using SIG_IGN, the sigsuspend() call below would not stop on |
e99525f9 JD |
154 | * SIGWINCH. |
155 | */ | |
1da177e4 LT |
156 | |
157 | signal(SIGWINCH, winch_handler); | |
158 | sigfillset(&sigs); | |
ed1b58d8 | 159 | /* Block all signals possible. */ |
e99525f9 JD |
160 | if (sigprocmask(SIG_SETMASK, &sigs, NULL) < 0) { |
161 | printk(UM_KERN_ERR "winch_thread : sigprocmask failed, " | |
162 | "errno = %d\n", errno); | |
1da177e4 LT |
163 | exit(1); |
164 | } | |
ed1b58d8 BS |
165 | /* In sigsuspend(), block anything else than SIGWINCH. */ |
166 | sigdelset(&sigs, SIGWINCH); | |
1da177e4 | 167 | |
e99525f9 JD |
168 | if (setsid() < 0) { |
169 | printk(UM_KERN_ERR "winch_thread : setsid failed, errno = %d\n", | |
170 | errno); | |
1da177e4 LT |
171 | exit(1); |
172 | } | |
173 | ||
cb8fa61c | 174 | if (ioctl(pty_fd, TIOCSCTTY, 0) < 0) { |
8ca842c4 JD |
175 | printk(UM_KERN_ERR "winch_thread : TIOCSCTTY failed on " |
176 | "fd %d err = %d\n", pty_fd, errno); | |
177 | exit(1); | |
178 | } | |
179 | ||
cb8fa61c | 180 | if (tcsetpgrp(pty_fd, os_getpid()) < 0) { |
8ca842c4 JD |
181 | printk(UM_KERN_ERR "winch_thread : tcsetpgrp failed on " |
182 | "fd %d err = %d\n", pty_fd, errno); | |
1da177e4 LT |
183 | exit(1); |
184 | } | |
185 | ||
e99525f9 JD |
186 | /* |
187 | * These are synchronization calls between various UML threads on the | |
1da177e4 LT |
188 | * host - since they are not different kernel threads, we cannot use |
189 | * kernel semaphores. We don't use SysV semaphores because they are | |
e99525f9 JD |
190 | * persistent. |
191 | */ | |
8ca842c4 | 192 | count = read(pipe_fd, &c, sizeof(c)); |
e99525f9 JD |
193 | if (count != sizeof(c)) |
194 | printk(UM_KERN_ERR "winch_thread : failed to read " | |
8ca842c4 | 195 | "synchronization byte, err = %d\n", errno); |
1da177e4 | 196 | |
e99525f9 JD |
197 | while(1) { |
198 | /* | |
199 | * This will be interrupted by SIGWINCH only, since | |
42a359e3 JD |
200 | * other signals are blocked. |
201 | */ | |
ed1b58d8 | 202 | sigsuspend(&sigs); |
1da177e4 | 203 | |
8ca842c4 | 204 | count = write(pipe_fd, &c, sizeof(c)); |
e99525f9 JD |
205 | if (count != sizeof(c)) |
206 | printk(UM_KERN_ERR "winch_thread : write failed, " | |
8ca842c4 | 207 | "err = %d\n", errno); |
1da177e4 LT |
208 | } |
209 | } | |
210 | ||
42a359e3 JD |
211 | static int winch_tramp(int fd, struct tty_struct *tty, int *fd_out, |
212 | unsigned long *stack_out) | |
1da177e4 LT |
213 | { |
214 | struct winch_data data; | |
1f96ddb4 | 215 | int fds[2], n, err; |
1da177e4 LT |
216 | char c; |
217 | ||
218 | err = os_pipe(fds, 1, 1); | |
e99525f9 JD |
219 | if (err < 0) { |
220 | printk(UM_KERN_ERR "winch_tramp : os_pipe failed, err = %d\n", | |
221 | -err); | |
1f96ddb4 | 222 | goto out; |
1da177e4 LT |
223 | } |
224 | ||
225 | data = ((struct winch_data) { .pty_fd = fd, | |
1d2ddcfb | 226 | .pipe_fd = fds[1] } ); |
e99525f9 JD |
227 | /* |
228 | * CLONE_FILES so this thread doesn't hold open files which are open | |
42a359e3 JD |
229 | * now, but later closed in a different thread. This is a |
230 | * problem with /dev/net/tun, which if held open by this | |
231 | * thread, prevents the TUN/TAP device from being reused. | |
1d2ddcfb | 232 | */ |
c4399016 | 233 | err = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out); |
e99525f9 JD |
234 | if (err < 0) { |
235 | printk(UM_KERN_ERR "fork of winch_thread failed - errno = %d\n", | |
236 | -err); | |
1f96ddb4 | 237 | goto out_close; |
1da177e4 LT |
238 | } |
239 | ||
1da177e4 | 240 | *fd_out = fds[0]; |
8ca842c4 | 241 | n = read(fds[0], &c, sizeof(c)); |
e99525f9 JD |
242 | if (n != sizeof(c)) { |
243 | printk(UM_KERN_ERR "winch_tramp : failed to read " | |
244 | "synchronization byte\n"); | |
8ca842c4 | 245 | printk(UM_KERN_ERR "read failed, err = %d\n", errno); |
e99525f9 JD |
246 | printk(UM_KERN_ERR "fd %d will not support SIGWINCH\n", fd); |
247 | err = -EINVAL; | |
1d2ddcfb | 248 | goto out_close; |
1da177e4 | 249 | } |
89df6bfc EGM |
250 | |
251 | if (os_set_fd_block(*fd_out, 0)) { | |
e99525f9 JD |
252 | printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd " |
253 | "non-blocking.\n"); | |
89df6bfc EGM |
254 | goto out_close; |
255 | } | |
256 | ||
257 | return err; | |
1f96ddb4 JD |
258 | |
259 | out_close: | |
8ca842c4 JD |
260 | close(fds[1]); |
261 | close(fds[0]); | |
1f96ddb4 JD |
262 | out: |
263 | return err; | |
1da177e4 LT |
264 | } |
265 | ||
266 | void register_winch(int fd, struct tty_struct *tty) | |
267 | { | |
42a359e3 JD |
268 | unsigned long stack; |
269 | int pid, thread, count, thread_fd = -1; | |
1da177e4 LT |
270 | char c = 1; |
271 | ||
e99525f9 | 272 | if (!isatty(fd)) |
1da177e4 LT |
273 | return; |
274 | ||
275 | pid = tcgetpgrp(fd); | |
6aa802ce | 276 | if (!is_skas_winch(pid, fd, tty) && (pid == -1)) { |
42a359e3 JD |
277 | thread = winch_tramp(fd, tty, &thread_fd, &stack); |
278 | if (thread < 0) | |
279 | return; | |
280 | ||
281 | register_winch_irq(thread_fd, fd, thread, tty, stack); | |
282 | ||
8ca842c4 | 283 | count = write(thread_fd, &c, sizeof(c)); |
e99525f9 JD |
284 | if (count != sizeof(c)) |
285 | printk(UM_KERN_ERR "register_winch : failed to write " | |
8ca842c4 | 286 | "synchronization byte, err = %d\n", errno); |
1da177e4 LT |
287 | } |
288 | } |