Contents of /tags/mkinitrd-6_2_3/busybox/console-tools/openvt.c
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Mon May 31 20:54:44 2010 UTC (14 years, 4 months ago) by niro
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Mon May 31 20:54:44 2010 UTC (14 years, 4 months ago) by niro
File MIME type: text/plain
File size: 4638 byte(s)
tagged 'mkinitrd-6_2_3'
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * openvt.c - open a vt to run a command. |
4 | * |
5 | * busyboxed by Quy Tonthat <quy@signal3.com> |
6 | * hacked by Tito <farmatito@tiscali.it> |
7 | * |
8 | * Licensed under GPLv2 or later, see file LICENSE in this tarball for details. |
9 | */ |
10 | |
11 | #include <linux/vt.h> |
12 | #include "libbb.h" |
13 | |
14 | /* "Standard" openvt's man page (we do not support all of this): |
15 | |
16 | openvt [-c NUM] [-fsulv] [--] [command [args]] |
17 | |
18 | Find the first available VT, and run command on it. Stdio is directed |
19 | to that VT. If no command is specified then $SHELL is used. |
20 | |
21 | -c NUM |
22 | Use the given VT number, not the first free one. |
23 | -f |
24 | Force opening a VT: don't try to check if VT is already in use. |
25 | -s |
26 | Switch to the new VT when starting the command. |
27 | The VT of the new command will be made the new current VT. |
28 | -u |
29 | Figure out the owner of the current VT, and run login as that user. |
30 | Suitable to be called by init. Shouldn't be used with -c or -l. |
31 | -l |
32 | Make the command a login shell: a "-" is prepended to the argv[0] |
33 | when command is executed. |
34 | -v |
35 | Verbose. |
36 | -w |
37 | Wait for command to complete. If -w and -s are used together, |
38 | switch back to the controlling terminal when the command completes. |
39 | |
40 | bbox: |
41 | -u: not implemented |
42 | -f: always in effect |
43 | -l: not implemented, ignored |
44 | -v: ignored |
45 | -ws: does NOT switch back |
46 | */ |
47 | |
48 | /* Helper: does this fd understand VT_xxx? */ |
49 | static int not_vt_fd(int fd) |
50 | { |
51 | struct vt_stat vtstat; |
52 | return ioctl(fd, VT_GETSTATE, &vtstat); /* !0: error, it's not VT fd */ |
53 | } |
54 | |
55 | /* Helper: get a fd suitable for VT_xxx */ |
56 | static int get_vt_fd(void) |
57 | { |
58 | int fd; |
59 | |
60 | /* Do we, by chance, already have it? */ |
61 | for (fd = 0; fd < 3; fd++) |
62 | if (!not_vt_fd(fd)) |
63 | return fd; |
64 | fd = open(DEV_CONSOLE, O_RDONLY | O_NONBLOCK); |
65 | if (fd >= 0 && !not_vt_fd(fd)) |
66 | return fd; |
67 | bb_error_msg_and_die("can't find open VT"); |
68 | } |
69 | |
70 | static int find_free_vtno(void) |
71 | { |
72 | int vtno; |
73 | int fd = get_vt_fd(); |
74 | |
75 | errno = 0; |
76 | /*xfunc_error_retval = 3; - do we need compat? */ |
77 | if (ioctl(fd, VT_OPENQRY, &vtno) != 0 || vtno <= 0) |
78 | bb_perror_msg_and_die("can't find open VT"); |
79 | // Not really needed, grep for DAEMON_ONLY_SANITIZE |
80 | // if (fd > 2) |
81 | // close(fd); |
82 | return vtno; |
83 | } |
84 | |
85 | /* vfork scares gcc, it generates bigger code. |
86 | * Keep it away from main program. |
87 | * TODO: move to libbb; or adapt existing libbb's spawn(). |
88 | */ |
89 | static NOINLINE void vfork_child(char **argv) |
90 | { |
91 | if (vfork() == 0) { |
92 | /* CHILD */ |
93 | /* Try to make this VT our controlling tty */ |
94 | setsid(); /* lose old ctty */ |
95 | ioctl(STDIN_FILENO, TIOCSCTTY, 0 /* 0: don't forcibly steal */); |
96 | //bb_error_msg("our sid %d", getsid(0)); |
97 | //bb_error_msg("our pgrp %d", getpgrp()); |
98 | //bb_error_msg("VT's sid %d", tcgetsid(0)); |
99 | //bb_error_msg("VT's pgrp %d", tcgetpgrp(0)); |
100 | BB_EXECVP(argv[0], argv); |
101 | bb_perror_msg_and_die("exec %s", argv[0]); |
102 | } |
103 | } |
104 | |
105 | int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
106 | int openvt_main(int argc UNUSED_PARAM, char **argv) |
107 | { |
108 | char vtname[sizeof(VC_FORMAT) + sizeof(int)*3]; |
109 | struct vt_stat vtstat; |
110 | char *str_c; |
111 | int vtno; |
112 | int flags; |
113 | enum { |
114 | OPT_c = (1 << 0), |
115 | OPT_w = (1 << 1), |
116 | OPT_s = (1 << 2), |
117 | OPT_l = (1 << 3), |
118 | OPT_f = (1 << 4), |
119 | OPT_v = (1 << 5), |
120 | }; |
121 | |
122 | /* "+" - stop on first non-option */ |
123 | flags = getopt32(argv, "+c:wslfv", &str_c); |
124 | argv += optind; |
125 | |
126 | if (flags & OPT_c) { |
127 | /* Check for illegal vt number: < 1 or > 63 */ |
128 | vtno = xatou_range(str_c, 1, 63); |
129 | } else { |
130 | vtno = find_free_vtno(); |
131 | } |
132 | |
133 | /* Grab new VT */ |
134 | sprintf(vtname, VC_FORMAT, vtno); |
135 | /* (Try to) clean up stray open fds above fd 2 */ |
136 | bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL); |
137 | close(STDIN_FILENO); |
138 | /*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */ |
139 | xopen(vtname, O_RDWR); |
140 | xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat); |
141 | |
142 | if (flags & OPT_s) { |
143 | console_make_active(STDIN_FILENO, vtno); |
144 | } |
145 | |
146 | if (!argv[0]) { |
147 | argv--; |
148 | argv[0] = getenv("SHELL"); |
149 | if (!argv[0]) |
150 | argv[0] = (char *) DEFAULT_SHELL; |
151 | /*argv[1] = NULL; - already is */ |
152 | } |
153 | |
154 | xdup2(STDIN_FILENO, STDOUT_FILENO); |
155 | xdup2(STDIN_FILENO, STDERR_FILENO); |
156 | |
157 | #ifdef BLOAT |
158 | { |
159 | /* Handle -l (login shell) option */ |
160 | const char *prog = argv[0]; |
161 | if (flags & OPT_l) |
162 | argv[0] = xasprintf("-%s", argv[0]); |
163 | } |
164 | #endif |
165 | |
166 | vfork_child(argv); |
167 | if (flags & OPT_w) { |
168 | /* We have only one child, wait for it */ |
169 | safe_waitpid(-1, NULL, 0); /* loops on EINTR */ |
170 | if (flags & OPT_s) { |
171 | console_make_active(STDIN_FILENO, vtstat.v_active); |
172 | // Compat: even with -c N (try to) disallocate: |
173 | // # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5 |
174 | // openvt: could not deallocate console 9 |
175 | xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno); |
176 | } |
177 | } |
178 | return EXIT_SUCCESS; |
179 | } |