busybox/coreutils/ln.c

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/* vi: set sw=4 ts=4: */
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/*
* Mini ln implementation for busybox
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
//config:config LN
//config: bool "ln (4.9 kb)"
//config: default y
//config: help
//config: ln is used to create hard or soft links between files.
//applet:IF_LN(APPLET_NOEXEC(ln, ln, BB_DIR_BIN, BB_SUID_DROP, ln))
//kbuild:lib-$(CONFIG_LN) += ln.o
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/* BB_AUDIT SUSv3 compliant */
/* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */
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/* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */
//usage:#define ln_trivial_usage
//usage: "[OPTIONS] TARGET... LINK|DIR"
//usage:#define ln_full_usage "\n\n"
//usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n"
//usage: "\n -s Make symlinks instead of hardlinks"
//usage: "\n -f Remove existing destinations"
//usage: "\n -n Don't dereference symlinks - treat like normal file"
//usage: "\n -b Make a backup of the target (if exists) before link operation"
//usage: "\n -S suf Use suffix instead of ~ when making backup files"
//usage: "\n -T Treat LINK as a file, not DIR"
//usage: "\n -v Verbose"
//usage:
//usage:#define ln_example_usage
//usage: "$ ln -s BusyBox /tmp/ls\n"
//usage: "$ ls -l /tmp/ls\n"
//usage: "lrwxrwxrwx 1 root root 7 Apr 12 18:39 ls -> BusyBox*\n"
#include "libbb.h"
/* This is a NOEXEC applet. Be very careful! */
#define LN_SYMLINK (1 << 0)
#define LN_FORCE (1 << 1)
#define LN_NODEREFERENCE (1 << 2)
#define LN_BACKUP (1 << 3)
#define LN_SUFFIX (1 << 4)
#define LN_VERBOSE (1 << 5)
#define LN_LINKFILE (1 << 6)
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int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ln_main(int argc, char **argv)
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{
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int status = EXIT_SUCCESS;
int opts;
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char *last;
char *src_name;
char *src;
char *suffix = (char*)"~";
struct stat statbuf;
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int (*link_func)(const char *, const char *);
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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opts = getopt32(argv, "^" "sfnbS:vT" "\0" "-1", &suffix);
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last = argv[argc - 1];
argv += optind;
argc -= optind;
if ((opts & LN_LINKFILE) && argc > 2) {
bb_error_msg_and_die("-T accepts 2 args max");
}
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if (!argv[1]) {
/* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */
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*--argv = last;
/* xstrdup is needed: "ln -s PATH/TO/FILE/" is equivalent to
* "ln -s PATH/TO/FILE/ FILE", not "ln -s PATH/TO/FILE FILE"
*/
last = bb_get_last_path_component_strip(xstrdup(last));
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}
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do {
src_name = NULL;
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src = last;
if (is_directory(src,
(opts & LN_NODEREFERENCE) ^ LN_NODEREFERENCE
)
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) {
if (opts & LN_LINKFILE) {
bb_error_msg_and_die("'%s' is a directory", src);
}
src_name = xstrdup(*argv);
src = concat_path_file(src, bb_get_last_path_component_strip(src_name));
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free(src_name);
src_name = src;
}
if (!(opts & LN_SYMLINK) && stat(*argv, &statbuf)) {
// coreutils: "ln dangling_symlink new_hardlink" works
if (lstat(*argv, &statbuf) || !S_ISLNK(statbuf.st_mode)) {
bb_simple_perror_msg(*argv);
status = EXIT_FAILURE;
free(src_name);
continue;
}
}
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if (opts & LN_BACKUP) {
char *backup;
backup = xasprintf("%s%s", src, suffix);
if (rename(src, backup) < 0 && errno != ENOENT) {
bb_simple_perror_msg(src);
status = EXIT_FAILURE;
free(backup);
continue;
}
free(backup);
/*
* When the source and dest are both hard links to the same
* inode, a rename may succeed even though nothing happened.
* Therefore, always unlink().
*/
unlink(src);
} else if (opts & LN_FORCE) {
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unlink(src);
}
link_func = link;
if (opts & LN_SYMLINK) {
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link_func = symlink;
}
if (opts & LN_VERBOSE) {
printf("'%s' -> '%s'\n", src, *argv);
}
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if (link_func(*argv, src) != 0) {
bb_simple_perror_msg(src);
status = EXIT_FAILURE;
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}
free(src_name);
} while ((++argv)[1]);
return status;
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}