1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
|
/* vi: set sw=4 ts=4: */
/*
* openvt.c - open a vt to run a command.
*
* busyboxed by Quy Tonthat <quy@signal3.com>
* hacked by Tito <farmatito@tiscali.it>
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config OPENVT
//config: bool "openvt (7 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: This program is used to start a command on an unused
//config: virtual terminal.
//applet:IF_OPENVT(APPLET(openvt, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_OPENVT) += openvt.o
//usage:#define openvt_trivial_usage
//usage: "[-c N] [-sw] [PROG ARGS]"
//usage:#define openvt_full_usage "\n\n"
//usage: "Start PROG on a new virtual terminal\n"
//usage: "\n -c N Use specified VT"
//usage: "\n -s Switch to the VT"
/* //usage: "\n -l Run PROG as login shell (by prepending '-')" */
//usage: "\n -w Wait for PROG to exit"
//usage:
//usage:#define openvt_example_usage
//usage: "openvt 2 /bin/ash\n"
#include <linux/vt.h>
#include "libbb.h"
/* "Standard" openvt's man page (we do not support all of this):
openvt [-c NUM] [-fsulv] [--] [command [args]]
Find the first available VT, and run command on it. Stdio is directed
to that VT. If no command is specified then $SHELL is used.
-c NUM
Use the given VT number, not the first free one.
-f
Force opening a VT: don't try to check if VT is already in use.
-s
Switch to the new VT when starting the command.
The VT of the new command will be made the new current VT.
-u
Figure out the owner of the current VT, and run login as that user.
Suitable to be called by init. Shouldn't be used with -c or -l.
-l
Make the command a login shell: a "-" is prepended to the argv[0]
when command is executed.
-v
Verbose.
-w
Wait for command to complete. If -w and -s are used together,
switch back to the controlling terminal when the command completes.
bbox:
-u: not implemented
-f: always in effect
-l: not implemented, ignored
-v: ignored
-ws: does NOT switch back
*/
/* Helper: does this fd understand VT_xxx? */
static int not_vt_fd(int fd)
{
struct vt_stat vtstat;
return ioctl(fd, VT_GETSTATE, &vtstat); /* !0: error, it's not VT fd */
}
/* Helper: get a fd suitable for VT_xxx */
static int get_vt_fd(void)
{
int fd;
/* Do we, by chance, already have it? */
for (fd = 0; fd < 3; fd++)
if (!not_vt_fd(fd))
return fd;
fd = open(DEV_CONSOLE, O_RDONLY | O_NONBLOCK);
if (fd >= 0 && !not_vt_fd(fd))
return fd;
bb_error_msg_and_die("can't find open VT");
}
static int find_free_vtno(void)
{
int vtno;
int fd = get_vt_fd();
errno = 0;
/*xfunc_error_retval = 3; - do we need compat? */
if (ioctl(fd, VT_OPENQRY, &vtno) != 0 || vtno <= 0)
bb_perror_msg_and_die("can't find open VT");
// Not really needed, grep for DAEMON_ONLY_SANITIZE
// if (fd > 2)
// close(fd);
return vtno;
}
/* vfork scares gcc, it generates bigger code.
* Keep it away from main program.
* TODO: move to libbb; or adapt existing libbb's spawn().
*/
static NOINLINE void vfork_child(char **argv)
{
if (vfork() == 0) {
/* CHILD */
/* Try to make this VT our controlling tty */
setsid(); /* lose old ctty */
ioctl(STDIN_FILENO, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
//bb_error_msg("our sid %d", getsid(0));
//bb_error_msg("our pgrp %d", getpgrp());
//bb_error_msg("VT's sid %d", tcgetsid(0));
//bb_error_msg("VT's pgrp %d", tcgetpgrp(0));
BB_EXECVP_or_die(argv);
}
}
int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int openvt_main(int argc UNUSED_PARAM, char **argv)
{
char vtname[sizeof(VC_FORMAT) + sizeof(int)*3];
struct vt_stat vtstat;
char *str_c;
int vtno;
int flags;
enum {
OPT_c = (1 << 0),
OPT_w = (1 << 1),
OPT_s = (1 << 2),
OPT_l = (1 << 3),
OPT_f = (1 << 4),
OPT_v = (1 << 5),
};
/* "+" - stop on first non-option */
flags = getopt32(argv, "+c:wslfv", &str_c);
argv += optind;
if (flags & OPT_c) {
/* Check for illegal vt number: < 1 or > 63 */
vtno = xatou_range(str_c, 1, 63);
} else {
vtno = find_free_vtno();
}
/* Grab new VT */
sprintf(vtname, VC_FORMAT, vtno);
/* (Try to) clean up stray open fds above fd 2 */
bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL);
close(STDIN_FILENO);
/*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */
xopen(vtname, O_RDWR);
xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat);
if (flags & OPT_s) {
console_make_active(STDIN_FILENO, vtno);
}
if (!argv[0]) {
argv--;
argv[0] = (char *) get_shell_name();
/*argv[1] = NULL; - already is */
}
xdup2(STDIN_FILENO, STDOUT_FILENO);
xdup2(STDIN_FILENO, STDERR_FILENO);
#ifdef BLOAT
{
/* Handle -l (login shell) option */
const char *prog = argv[0];
if (flags & OPT_l)
argv[0] = xasprintf("-%s", argv[0]);
}
#endif
vfork_child(argv);
if (flags & OPT_w) {
/* We have only one child, wait for it */
safe_waitpid(-1, NULL, 0); /* loops on EINTR */
if (flags & OPT_s) {
console_make_active(STDIN_FILENO, vtstat.v_active);
// Compat: even with -c N (try to) disallocate:
// # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5
// openvt: could not deallocate console 9
xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno);
}
}
return EXIT_SUCCESS;
}
|
