busybox/util-linux/setsid.c

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/* vi: set sw=4 ts=4: */
/*
* setsid.c -- execute a command in a new session
* Rick Sladkey <jrs@world.std.com>
* In the public domain.
*
* 1999-02-22 Arkadiusz Mickiewicz <misiek@pld.ORG.PL>
* - added Native Language Support
*
* 2001-01-18 John Fremlin <vii@penguinpowered.com>
* - fork in case we are process group leader
*
* 2004-11-12 Paul Fox
* - busyboxed
*/
//config:config SETSID
//config: bool "setsid (3.9 kb)"
//config: default y
//config: help
//config: setsid runs a program in a new session
//applet:IF_SETSID(APPLET(setsid, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_SETSID) += setsid.o
//usage:#define setsid_trivial_usage
//usage: "[-c] PROG ARGS"
//usage:#define setsid_full_usage "\n\n"
//usage: "Run PROG in a new session. PROG will have no controlling terminal\n"
//usage: "and will not be affected by keyboard signals (^C etc).\n"
//usage: "\n -c Set controlling terminal to stdin"
#include "libbb.h"
int setsid_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int setsid_main(int argc UNUSED_PARAM, char **argv)
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{
unsigned opt;
getopt32: remove opt_complementary function old new delta vgetopt32 1318 1392 +74 runsvdir_main 703 713 +10 bb_make_directory 423 425 +2 collect_cpu 546 545 -1 opt_chars 3 - -3 opt_complementary 4 - -4 tftpd_main 567 562 -5 ntp_init 476 471 -5 zcip_main 1266 1256 -10 xxd_main 428 418 -10 whois_main 140 130 -10 who_main 463 453 -10 which_main 212 202 -10 wget_main 2535 2525 -10 watchdog_main 291 281 -10 watch_main 222 212 -10 vlock_main 399 389 -10 uuencode_main 332 322 -10 uudecode_main 316 306 -10 unlink_main 45 35 -10 udhcpd_main 1482 1472 -10 udhcpc_main 2762 2752 -10 tune2fs_main 290 280 -10 tunctl_main 366 356 -10 truncate_main 218 208 -10 tr_main 518 508 -10 time_main 1134 1124 -10 tftp_main 286 276 -10 telnetd_main 1873 1863 -10 tcpudpsvd_main 1785 1775 -10 taskset_main 521 511 -10 tar_main 1009 999 -10 tail_main 1644 1634 -10 syslogd_main 1967 1957 -10 switch_root_main 368 358 -10 svlogd_main 1454 1444 -10 sv 1296 1286 -10 stat_main 104 94 -10 start_stop_daemon_main 1028 1018 -10 split_main 542 532 -10 sort_main 796 786 -10 slattach_main 624 614 -10 shuf_main 504 494 -10 setsid_main 96 86 -10 setserial_main 1132 1122 -10 setfont_main 388 378 -10 setconsole_main 78 68 -10 sendmail_main 1209 1199 -10 sed_main 677 667 -10 script_main 1077 1067 -10 run_parts_main 325 315 -10 rtcwake_main 454 444 -10 rm_main 175 165 -10 reformime_main 119 109 -10 readlink_main 123 113 -10 rdate_main 246 236 -10 pwdx_main 189 179 -10 pstree_main 317 307 -10 pscan_main 663 653 -10 popmaildir_main 818 808 -10 pmap_main 80 70 -10 nc_main 1042 1032 -10 mv_main 558 548 -10 mountpoint_main 477 467 -10 mount_main 1264 1254 -10 modprobe_main 768 758 -10 modinfo_main 333 323 -10 mktemp_main 200 190 -10 mkswap_main 324 314 -10 mkfs_vfat_main 1489 1479 -10 microcom_main 715 705 -10 md5_sha1_sum_main 521 511 -10 man_main 867 857 -10 makedevs_main 1052 1042 -10 ls_main 563 553 -10 losetup_main 432 422 -10 loadfont_main 89 79 -10 ln_main 524 514 -10 link_main 75 65 -10 ipcalc_main 544 534 -10 iostat_main 2397 2387 -10 install_main 768 758 -10 id_main 480 470 -10 i2cset_main 1239 1229 -10 i2cget_main 380 370 -10 i2cdump_main 1482 1472 -10 i2cdetect_main 682 672 -10 hwclock_main 406 396 -10 httpd_main 741 731 -10 grep_main 837 827 -10 getty_main 1559 1549 -10 fuser_main 297 287 -10 ftpgetput_main 345 335 -10 ftpd_main 2232 2222 -10 fstrim_main 251 241 -10 fsfreeze_main 77 67 -10 fsck_minix_main 2921 2911 -10 flock_main 314 304 -10 flashcp_main 740 730 -10 flash_eraseall_main 833 823 -10 fdformat_main 532 522 -10 expand_main 680 670 -10 eject_main 335 325 -10 dumpleases_main 630 620 -10 du_main 314 304 -10 dos2unix_main 441 431 -10 diff_main 1350 1340 -10 df_main 1064 1054 -10 date_main 1095 1085 -10 cut_main 961 951 -10 cryptpw_main 228 218 -10 crontab_main 575 565 -10 crond_main 1149 1139 -10 cp_main 370 360 -10 common_traceroute_main 3834 3824 -10 common_ping_main 1767 1757 -10 comm_main 239 229 -10 cmp_main 655 645 -10 chrt_main 379 369 -10 chpst_main 704 694 -10 chpasswd_main 308 298 -10 chown_main 171 161 -10 chmod_main 158 148 -10 cat_main 428 418 -10 bzip2_main 120 110 -10 blkdiscard_main 264 254 -10 base64_main 221 211 -10 arping_main 1665 1655 -10 ar_main 556 546 -10 adjtimex_main 406 396 -10 adduser_main 882 872 -10 addgroup_main 411 401 -10 acpid_main 1198 1188 -10 optstring 11 - -11 opt_string 18 - -18 OPT_STR 25 - -25 ubi_tools_main 1288 1258 -30 ls_options 31 - -31 ------------------------------------------------------------------------------ (add/remove: 0/6 grow/shrink: 3/129 up/down: 86/-1383) Total: -1297 bytes text data bss dec hex filename 915428 485 6876 922789 e14a5 busybox_old 914629 485 6872 921986 e1182 busybox_unstripped Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
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/* +: stop on first non-opt */
opt = getopt32(argv, "^+" "c" "\0" "-1"/* at least one arg */);
argv += optind;
/* setsid() is allowed only when we are not a process group leader.
* Otherwise our PID serves as PGID of some existing process group
* and cannot be used as PGID of a new process group.
*
* Example: setsid() below fails when run alone in interactive shell:
* $ setsid PROG
* because shell's child (setsid) is put in a new process group.
* But doesn't fail if shell is not interactive
* (and therefore doesn't create process groups for pipes),
* or if setsid is not the first process in the process group:
* $ true | setsid PROG
* or if setsid is executed in backquotes (`setsid PROG`)...
*/
if (setsid() < 0) {
pid_t pid = fork_or_rexec(argv);
if (pid != 0) {
/* parent */
/* TODO:
* we can waitpid(pid, &status, 0) and then even
* emulate exitcode, making the behavior consistent
* in both forked and non forked cases.
* However, the code is larger and upstream
* does not do such trick.
*/
return EXIT_SUCCESS;
}
/* child */
/* now there should be no error: */
setsid();
}
if (opt) {
/* -c: set (with stealing) controlling tty */
ioctl(0, TIOCSCTTY, 1);
}
BB_EXECVP_or_die(argv);
}