busybox/util-linux/fallocate.c

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/* vi: set sw=4 ts=4: */
/*
* Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2, see file LICENSE in this source tree.
*/
//config:config FALLOCATE
//config: bool "fallocate (5 kb)"
//config: default y
//config: help
//config: Preallocate space for files.
//applet:IF_FALLOCATE(APPLET(fallocate, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_FALLOCATE) += fallocate.o
//usage:#define fallocate_trivial_usage
//usage: "[-o OFS] -l LEN FILE"
// fallocate [-c|-p|-z] [-n] [-o OFS] -l LEN FILE
// fallocate -d [-o OFS] [-l LEN] FILE
//usage:#define fallocate_full_usage "\n\n"
//usage: "Preallocate space for FILE\n"
// "\n -c Remove range"
// "\n -p Make hole"
// "\n -z Zero and allocate range"
// "\n -d Convert zeros to holes"
// "\n -n Keep size"
//usage: "\n -o OFS Offset of range"
//usage: "\n -l LEN Length of range"
//Upstream options:
//The options --collapse-range, --dig-holes, --punch-hole and --zero-range
//are mutually exclusive.
//-c, --collapse-range
// Removes a byte range from a file, without leaving a hole. The byte range
// to be collapsed starts at offset and continues for length bytes.
// At the completion of the operation, the contents of the file starting
// at the location offset+length will be appended at the location offset,
// and the file will be length bytes smaller. The option --keep-size may
// not be specified for the collapse-range operation.
//-d, --dig-holes
// Detect and dig holes. This makes the file sparse in-place, without using
// extra disk space. The minimum size of the hole depends on filesystem I/O
// block size (usually 4096 bytes). Also,
//-l, --length length
// Specifies the length of the range, in bytes.
//-n, --keep-size
// Do not modify the apparent length of the file. This may effectively
// allocate blocks past EOF, which can be removed with a truncate.
//-o, --offset offset
// Specifies the beginning offset of the range, in bytes.
//-p, --punch-hole
// Deallocates space (i.e., creates a hole) in the byte range starting
// at offset and continuing for length bytes. Within the specified range,
// partial filesystem blocks are zeroed, and whole
// filesystem blocks are removed from the file. After a successful call,
// subsequent reads from this range will return zeroes. This option may not
// be specified at the same time as the
// --zero-range option. Also, when using this option, --keep-size is implied.
//-z, --zero-range
// Zeroes space in the byte range starting at offset and continuing for
// length bytes. Within the specified range, blocks are preallocated for
// the regions that span the holes in the file. After
// a successful call, subsequent reads from this range will return zeroes.
// Zeroing is done within the filesystem preferably by converting the range
// into unwritten extents. This approach means that the specified range
// will not be physically zeroed out on the device (except for partial
// blocks at the either end of the range), and I/O is (otherwise) required
// only to update metadata.
// Option --keep-size can be specified to prevent file length modification.
#include "libbb.h"
int fallocate_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int fallocate_main(int argc UNUSED_PARAM, char **argv)
{
const char *str_l;
const char *str_o = "0";
off_t ofs, len;
unsigned opts;
int fd;
/* exactly one non-option arg */
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
opts = getopt32(argv, "^" "l:o:" "\0" "=1", &str_l, &str_o);
if (!(opts & 1))
bb_show_usage();
ofs = xatoull_sfx(str_o, kmg_i_suffixes);
len = xatoull_sfx(str_l, kmg_i_suffixes);
argv += optind;
fd = xopen3(*argv, O_RDWR | O_CREAT, 0666);
/* posix_fallocate has unusual method of returning error */
/* maybe use Linux-specific fallocate(int fd, int mode, off_t offset, off_t len) instead? */
if ((errno = posix_fallocate(fd, ofs, len)) != 0)
bb_perror_msg_and_die("fallocate '%s'", *argv);
/* util-linux also performs fsync(fd); */
return EXIT_SUCCESS;
}