[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * openvt.c - open a vt to run a command.
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| 4 | *
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| 5 | * busyboxed by Quy Tonthat <quy@signal3.com>
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| 6 | * hacked by Tito <farmatito@tiscali.it>
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| 7 | *
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| 8 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 9 | */
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| 10 |
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| 11 | #include <linux/vt.h>
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| 12 | #include "libbb.h"
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| 13 |
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| 14 | /* "Standard" openvt's man page (we do not support all of this):
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| 15 |
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| 16 | openvt [-c NUM] [-fsulv] [--] [command [args]]
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| 17 |
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| 18 | Find the first available VT, and run command on it. Stdio is directed
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| 19 | to that VT. If no command is specified then $SHELL is used.
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| 20 |
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| 21 | -c NUM
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| 22 | Use the given VT number, not the first free one.
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| 23 | -f
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| 24 | Force opening a VT: don't try to check if VT is already in use.
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| 25 | -s
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| 26 | Switch to the new VT when starting the command.
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| 27 | The VT of the new command will be made the new current VT.
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| 28 | -u
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| 29 | Figure out the owner of the current VT, and run login as that user.
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| 30 | Suitable to be called by init. Shouldn't be used with -c or -l.
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| 31 | -l
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| 32 | Make the command a login shell: a "-" is prepended to the argv[0]
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| 33 | when command is executed.
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| 34 | -v
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| 35 | Verbose.
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| 36 | -w
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| 37 | Wait for command to complete. If -w and -s are used together,
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| 38 | switch back to the controlling terminal when the command completes.
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| 39 |
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| 40 | bbox:
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| 41 | -u: not implemented
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| 42 | -f: always in effect
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| 43 | -l: not implemented, ignored
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| 44 | -v: ignored
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| 45 | -ws: does NOT switch back
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| 46 | */
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| 47 |
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| 48 | /* Helper: does this fd understand VT_xxx? */
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| 49 | static int not_vt_fd(int fd)
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| 50 | {
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| 51 | struct vt_stat vtstat;
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| 52 | return ioctl(fd, VT_GETSTATE, &vtstat); /* !0: error, it's not VT fd */
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| 53 | }
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| 54 |
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| 55 | /* Helper: get a fd suitable for VT_xxx */
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| 56 | static int get_vt_fd(void)
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| 57 | {
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| 58 | int fd;
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| 59 |
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| 60 | /* Do we, by chance, already have it? */
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| 61 | for (fd = 0; fd < 3; fd++)
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| 62 | if (!not_vt_fd(fd))
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| 63 | return fd;
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| 64 | fd = open(DEV_CONSOLE, O_RDONLY | O_NONBLOCK);
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| 65 | if (fd >= 0 && !not_vt_fd(fd))
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| 66 | return fd;
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| 67 | bb_error_msg_and_die("can't find open VT");
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| 68 | }
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| 69 |
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| 70 | static int find_free_vtno(void)
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| 71 | {
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| 72 | int vtno;
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| 73 | int fd = get_vt_fd();
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| 74 |
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| 75 | errno = 0;
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| 76 | /*xfunc_error_retval = 3; - do we need compat? */
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| 77 | if (ioctl(fd, VT_OPENQRY, &vtno) != 0 || vtno <= 0)
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| 78 | bb_perror_msg_and_die("can't find open VT");
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| 79 | // Not really needed, grep for DAEMON_ONLY_SANITIZE
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| 80 | // if (fd > 2)
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| 81 | // close(fd);
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| 82 | return vtno;
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| 83 | }
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| 84 |
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| 85 | /* vfork scares gcc, it generates bigger code.
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| 86 | * Keep it away from main program.
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| 87 | * TODO: move to libbb; or adapt existing libbb's spawn().
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| 88 | */
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| 89 | static NOINLINE void vfork_child(char **argv)
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| 90 | {
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| 91 | if (vfork() == 0) {
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| 92 | /* CHILD */
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| 93 | /* Try to make this VT our controlling tty */
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| 94 | setsid(); /* lose old ctty */
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| 95 | ioctl(STDIN_FILENO, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
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| 96 | //bb_error_msg("our sid %d", getsid(0));
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| 97 | //bb_error_msg("our pgrp %d", getpgrp());
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| 98 | //bb_error_msg("VT's sid %d", tcgetsid(0));
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| 99 | //bb_error_msg("VT's pgrp %d", tcgetpgrp(0));
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| 100 | BB_EXECVP_or_die(argv);
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| 101 | }
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| 102 | }
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| 103 |
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| 104 | int openvt_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 105 | int openvt_main(int argc UNUSED_PARAM, char **argv)
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| 106 | {
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| 107 | char vtname[sizeof(VC_FORMAT) + sizeof(int)*3];
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| 108 | struct vt_stat vtstat;
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| 109 | char *str_c;
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| 110 | int vtno;
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| 111 | int flags;
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| 112 | enum {
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| 113 | OPT_c = (1 << 0),
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| 114 | OPT_w = (1 << 1),
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| 115 | OPT_s = (1 << 2),
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| 116 | OPT_l = (1 << 3),
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| 117 | OPT_f = (1 << 4),
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| 118 | OPT_v = (1 << 5),
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| 119 | };
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| 120 |
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| 121 | /* "+" - stop on first non-option */
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| 122 | flags = getopt32(argv, "+c:wslfv", &str_c);
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| 123 | argv += optind;
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| 124 |
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| 125 | if (flags & OPT_c) {
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| 126 | /* Check for illegal vt number: < 1 or > 63 */
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| 127 | vtno = xatou_range(str_c, 1, 63);
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| 128 | } else {
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| 129 | vtno = find_free_vtno();
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| 130 | }
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| 131 |
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| 132 | /* Grab new VT */
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| 133 | sprintf(vtname, VC_FORMAT, vtno);
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| 134 | /* (Try to) clean up stray open fds above fd 2 */
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| 135 | bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS | DAEMON_ONLY_SANITIZE, NULL);
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| 136 | close(STDIN_FILENO);
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| 137 | /*setsid(); - BAD IDEA: after we exit, child is SIGHUPed... */
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| 138 | xopen(vtname, O_RDWR);
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| 139 | xioctl(STDIN_FILENO, VT_GETSTATE, &vtstat);
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| 140 |
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| 141 | if (flags & OPT_s) {
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| 142 | console_make_active(STDIN_FILENO, vtno);
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| 143 | }
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| 144 |
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| 145 | if (!argv[0]) {
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| 146 | argv--;
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| 147 | argv[0] = getenv("SHELL");
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| 148 | if (!argv[0])
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| 149 | argv[0] = (char *) DEFAULT_SHELL;
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| 150 | /*argv[1] = NULL; - already is */
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| 151 | }
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| 152 |
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| 153 | xdup2(STDIN_FILENO, STDOUT_FILENO);
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| 154 | xdup2(STDIN_FILENO, STDERR_FILENO);
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| 155 |
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| 156 | #ifdef BLOAT
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| 157 | {
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| 158 | /* Handle -l (login shell) option */
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| 159 | const char *prog = argv[0];
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| 160 | if (flags & OPT_l)
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| 161 | argv[0] = xasprintf("-%s", argv[0]);
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| 162 | }
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| 163 | #endif
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| 164 |
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| 165 | vfork_child(argv);
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| 166 | if (flags & OPT_w) {
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| 167 | /* We have only one child, wait for it */
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| 168 | safe_waitpid(-1, NULL, 0); /* loops on EINTR */
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| 169 | if (flags & OPT_s) {
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| 170 | console_make_active(STDIN_FILENO, vtstat.v_active);
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| 171 | // Compat: even with -c N (try to) disallocate:
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| 172 | // # /usr/app/kbd-1.12/bin/openvt -f -c 9 -ws sleep 5
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| 173 | // openvt: could not deallocate console 9
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| 174 | xioctl(STDIN_FILENO, VT_DISALLOCATE, (void*)(ptrdiff_t)vtno);
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| 175 | }
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| 176 | }
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| 177 | return EXIT_SUCCESS;
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| 178 | }
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