1 /* vi: set sw=4 ts=4: */
3 * openvt.c - open a vt to run a command.
5 * busyboxed by Quy Tonthat <quy@signal3.com>
6 * hacked by Tito <farmatito@tiscali.it>
8 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
14 /* "Standard" openvt's man page (we do not support all of this):
16 openvt [-c NUM] [-fsulv] [--] [command [args]]
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.
22 Use the given VT number, not the first free one.
24 Force opening a VT: don't try to check if VT is already in use.
26 Switch to the new VT when starting the command.
27 The VT of the new command will be made the new current VT.
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.
32 Make the command a login shell: a "-" is prepended to the argv[0]
33 when command is executed.
37 Wait for command to complete. If -w and -s are used together,
38 switch back to the controlling terminal when the command completes.
43 -l: not implemented, ignored
45 -ws: does NOT switch back
48 /* Helper: does this fd understand VT_xxx? */
49 static int not_vt_fd(int fd)
51 struct vt_stat vtstat;
52 return ioctl(fd, VT_GETSTATE, &vtstat); /* !0: error, it's not VT fd */
55 /* Helper: get a fd suitable for VT_xxx */
56 static int get_vt_fd(void)
60 /* Do we, by chance, already have it? */
61 for (fd = 0; fd < 3; fd++)
64 /* _only_ O_NONBLOCK: ask for neither read nor write perms */
65 /*FIXME: use? device_open(DEV_CONSOLE,0); */
66 fd = open(DEV_CONSOLE, O_NONBLOCK);
67 if (fd >= 0 && !not_vt_fd(fd))
69 bb_error_msg_and_die("can't find open VT");
72 static int find_free_vtno(void)
78 /*xfunc_error_retval = 3; - do we need compat? */
79 if (ioctl(fd, VT_OPENQRY, &vtno) != 0 || vtno <= 0)
80 bb_perror_msg_and_die("can't find open VT");
81 // Not really needed, grep for DAEMON_ONLY_SANITIZE
87 /* vfork scares gcc, it generates bigger code.
88 * Keep it away from main program.
89 * TODO: move to libbb; or adapt existing libbb's spawn().
91 static NOINLINE void vfork_child(char **argv)
95 /* Try to make this VT our controlling tty */
96 setsid(); /* lose old ctty */
97 ioctl(STDIN_FILENO, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
98 //bb_error_msg("our sid %d", getsid(0));
99 //bb_error_msg("our pgrp %d", getpgrp());
100 //bb_error_msg("VT's sid %d", tcgetsid(0));
101 //bb_error_msg("VT's pgrp %d", tcgetpgrp(0));
102 BB_EXECVP(argv[0], argv);
103 bb_perror_msg_and_die("exec %s", argv[0]);
107 int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
108 int openvt_main(int argc UNUSED_PARAM, char **argv)
110 char vtname[sizeof(VC_FORMAT) + sizeof(int)*3];
111 struct vt_stat vtstat;
124 /* "+" - stop on first non-option */
125 flags = getopt32(argv, "+c:wslfv", &str_c);
129 /* Check for illegal vt number: < 1 or > 63 */
130 vtno = xatou_range(str_c, 1, 63);
132 vtno = find_free_vtno();
136 sprintf(vtname, VC_FORMAT, vtno);
137 /* (Try to) clean up stray open fds above fd 2 */
138 bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL);
140 /*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */
141 xopen(vtname, O_RDWR);
142 xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat);
145 console_make_active(STDIN_FILENO, vtno);
150 argv[0] = getenv("SHELL");
152 argv[0] = (char *) DEFAULT_SHELL;
153 /*argv[1] = NULL; - already is */
156 xdup2(STDIN_FILENO, STDOUT_FILENO);
157 xdup2(STDIN_FILENO, STDERR_FILENO);
161 /* Handle -l (login shell) option */
162 const char *prog = argv[0];
164 argv[0] = xasprintf("-%s", argv[0]);
170 /* We have only one child, wait for it */
171 safe_waitpid(-1, NULL, 0); /* loops on EINTR */
173 console_make_active(STDIN_FILENO, vtstat.v_active);
174 // Compat: even with -c N (try to) disallocate:
175 // # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5
176 // openvt: could not deallocate console 9
177 xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno);