123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199 |
- /* 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 (7.2 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_simple_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_simple_perror_msg_and_die("can't find open VT");
- // Not really needed, grep for DAEMON_CLOSE_EXTRA_FDS
- // 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_daemon_helper(DAEMON_CLOSE_EXTRA_FDS);
- 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;
- }
|