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 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} 179