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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> | |
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 | */ |