source: branches/3.0/mindi-busybox/console-tools/openvt.c @ 3085

Last change on this file since 3085 was 2725, checked in by bruno, 8 years ago
  • Update mindi-busybox to 1.18.3 to avoid problems with the tar command which is now failing on recent versions with busybox 1.7.3
File size: 4.5 KB
Line 
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 source tree.
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
16openvt [-c NUM] [-fsulv] [--] [command [args]]
17
18Find the first available VT, and run command on it. Stdio is directed
19to 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
40bbox:
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? */
49static 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 */
56static 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
70static 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 */
89static 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_or_die(argv);
101    }
102}
103
104int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
105int openvt_main(int argc UNUSED_PARAM, char **argv)
106{
107    char vtname[sizeof(VC_FORMAT) + sizeof(int)*3];
108    struct vt_stat vtstat;
109    char *str_c;
110    int vtno;
111    int flags;
112    enum {
113        OPT_c = (1 << 0),
114        OPT_w = (1 << 1),
115        OPT_s = (1 << 2),
116        OPT_l = (1 << 3),
117        OPT_f = (1 << 4),
118        OPT_v = (1 << 5),
119    };
120
121    /* "+" - stop on first non-option */
122    flags = getopt32(argv, "+c:wslfv", &str_c);
123    argv += optind;
124
125    if (flags & OPT_c) {
126        /* Check for illegal vt number: < 1 or > 63 */
127        vtno = xatou_range(str_c, 1, 63);
128    } else {
129        vtno = find_free_vtno();
130    }
131
132    /* Grab new VT */
133    sprintf(vtname, VC_FORMAT, vtno);
134    /* (Try to) clean up stray open fds above fd 2 */
135    bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL);
136    close(STDIN_FILENO);
137    /*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */
138    xopen(vtname, O_RDWR);
139    xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat);
140
141    if (flags & OPT_s) {
142        console_make_active(STDIN_FILENO, vtno);
143    }
144
145    if (!argv[0]) {
146        argv--;
147        argv[0] = getenv("SHELL");
148        if (!argv[0])
149            argv[0] = (char *) DEFAULT_SHELL;
150        /*argv[1] = NULL; - already is */
151    }
152
153    xdup2(STDIN_FILENO, STDOUT_FILENO);
154    xdup2(STDIN_FILENO, STDERR_FILENO);
155
156#ifdef BLOAT
157    {
158    /* Handle -l (login shell) option */
159    const char *prog = argv[0];
160    if (flags & OPT_l)
161        argv[0] = xasprintf("-%s", argv[0]);
162    }
163#endif
164
165    vfork_child(argv);
166    if (flags & OPT_w) {
167        /* We have only one child, wait for it */
168        safe_waitpid(-1, NULL, 0); /* loops on EINTR */
169        if (flags & OPT_s) {
170            console_make_active(STDIN_FILENO, vtstat.v_active);
171            // Compat: even with -c N (try to) disallocate:
172            // # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5
173            // openvt: could not deallocate console 9
174            xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno);
175        }
176    }
177    return EXIT_SUCCESS;
178}
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