busybox/util-linux/flock.c

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/*
* Copyright (C) 2010 Timo Teras <timo.teras@iki.fi>
*
* This is free software, licensed under the GNU General Public License v2.
*/
//config:config FLOCK
//config: bool "flock (6.1 kb)"
//config: default y
//config: help
//config: Manage locks from shell scripts
//applet:IF_FLOCK(APPLET(flock, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_FLOCK) += flock.o
//usage:#define flock_trivial_usage
//usage: "[-sxun] FD|{FILE [-c] PROG ARGS}"
//usage:#define flock_full_usage "\n\n"
//usage: "[Un]lock file descriptor, or lock FILE, run PROG\n"
//usage: "\n -s Shared lock"
//usage: "\n -x Exclusive lock (default)"
//usage: "\n -u Unlock FD"
//usage: "\n -n Fail rather than wait"
#include <sys/file.h>
#include "libbb.h"
int flock_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int flock_main(int argc UNUSED_PARAM, char **argv)
{
int mode, opt, fd;
enum {
OPT_s = (1 << 0),
OPT_x = (1 << 1),
OPT_n = (1 << 2),
OPT_u = (1 << 3),
OPT_c = (1 << 4),
};
#if ENABLE_LONG_OPTS
static const char flock_longopts[] ALIGN1 =
"shared\0" No_argument "s"
"exclusive\0" No_argument "x"
"unlock\0" No_argument "u"
"nonblock\0" No_argument "n"
;
#endif
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>
2017-08-09 01:25:02 +05:30
opt = getopt32long(argv, "^+" "sxnu" "\0" "-1", flock_longopts);
argv += optind;
if (argv[1]) {
fd = open(argv[0], O_RDONLY|O_NOCTTY|O_CREAT, 0666);
if (fd < 0 && errno == EISDIR)
fd = open(argv[0], O_RDONLY|O_NOCTTY);
if (fd < 0)
bb_perror_msg_and_die("can't open '%s'", argv[0]);
//TODO? close_on_exec_on(fd);
} else {
fd = xatoi_positive(argv[0]);
}
argv++;
/* If it is "flock FILE -c PROG", then -c isn't caught by getopt32:
* we use "+" in order to support "flock -opt FILE PROG -with-opts",
* we need to remove -c by hand.
*/
if (argv[0]
&& argv[0][0] == '-'
&& ( (argv[0][1] == 'c' && !argv[0][2])
|| (ENABLE_LONG_OPTS && strcmp(argv[0] + 1, "-command") == 0)
)
) {
argv++;
if (argv[1])
bb_error_msg_and_die("-c takes only one argument");
opt |= OPT_c;
}
if (OPT_s == LOCK_SH && OPT_x == LOCK_EX && OPT_n == LOCK_NB && OPT_u == LOCK_UN) {
/* With suitably matched constants, mode setting is much simpler */
mode = opt & (LOCK_SH + LOCK_EX + LOCK_NB + LOCK_UN);
if (!(mode & ~LOCK_NB))
mode |= LOCK_EX;
} else {
if (opt & OPT_u)
mode = LOCK_UN;
else if (opt & OPT_s)
mode = LOCK_SH;
else
mode = LOCK_EX;
if (opt & OPT_n)
mode |= LOCK_NB;
}
if (flock(fd, mode) != 0) {
if (errno == EWOULDBLOCK)
return EXIT_FAILURE;
bb_perror_nomsg_and_die();
}
if (argv[0]) {
int rc;
if (opt & OPT_c) {
/* -c 'PROG ARGS' means "run sh -c 'PROG ARGS'" */
argv -= 2;
argv[0] = (char*)get_shell_name();
argv[1] = (char*)"-c";
/* argv[2] = "PROG ARGS"; */
/* argv[3] = NULL; */
}
rc = spawn_and_wait(argv);
if (rc < 0)
bb_simple_perror_msg(argv[0]);
return rc;
}
return EXIT_SUCCESS;
}