| /* vi: set sw=4 ts=4: */ |
| /* |
| * Mini ln implementation for busybox |
| * |
| * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> |
| * |
| * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
| */ |
| //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-$(CONFIG_LN) += ln.o |
| |
| /* BB_AUDIT SUSv3 compliant */ |
| /* BB_AUDIT GNU options missing: -d, -F, -i, and -v. */ |
| /* http://www.opengroup.org/onlinepubs/007904975/utilities/ln.html */ |
| |
| //usage:#define ln_trivial_usage |
| //usage: "[OPTIONS] TARGET... LINK|DIR" |
| //usage:#define ln_full_usage "\n\n" |
| //usage: "Create a link LINK or DIR/TARGET to the specified TARGET(s)\n" |
| //usage: "\n -s Make symlinks instead of hardlinks" |
| //usage: "\n -f Remove existing destinations" |
| //usage: "\n -n Don't dereference symlinks - treat like normal file" |
| //usage: "\n -b Make a backup of the target (if exists) before link operation" |
| //usage: "\n -S suf Use suffix instead of ~ when making backup files" |
| //usage: "\n -T Treat LINK as a file, not DIR" |
| //usage: "\n -v Verbose" |
| //usage: |
| //usage:#define ln_example_usage |
| //usage: "$ 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) |
| |
| int ln_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
| int ln_main(int argc, char **argv) |
| { |
| int status = EXIT_SUCCESS; |
| int opts; |
| char *last; |
| char *src_name; |
| char *src; |
| char *suffix = (char*)"~"; |
| struct stat statbuf; |
| int (*link_func)(const char *, const char *); |
| |
| opts = getopt32(argv, "^" "sfnbS:vT" "\0" "-1", &suffix); |
| /* |
| -s, --symbolic make symbolic links instead of hard links |
| -f, --force remove existing destination files |
| -n, --no-dereference treat LINK_NAME as a normal file if it is a symbolic link to a directory |
| -b like --backup but does not accept an argument |
| --backup[=CONTROL] make a backup of each existing destination file |
| -S, --suffix=SUFFIX override the usual backup suffix |
| -v, --verbose |
| -T, --no-target-directory |
| -d, -F, --directory allow the superuser to attempt to hard link directories |
| -i, --interactive prompt whether to remove destinations |
| -L, --logical dereference TARGETs that are symbolic links |
| -P, --physical make hard links directly to symbolic links |
| -r, --relative create symbolic links relative to link location |
| -t, --target-directory=DIRECTORY specify the DIRECTORY in which to create the links |
| */ |
| last = argv[argc - 1]; |
| argv += optind; |
| argc -= optind; |
| |
| if ((opts & LN_LINKFILE) && argc > 2) { |
| bb_simple_error_msg_and_die("-T accepts 2 args max"); |
| } |
| |
| if (!argv[1]) { |
| /* "ln PATH/TO/FILE" -> "ln PATH/TO/FILE FILE" */ |
| *--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)); |
| } |
| |
| do { |
| src_name = NULL; |
| src = last; |
| |
| if (is_directory(src, |
| /*followlinks:*/ !(opts & (LN_NODEREFERENCE|LN_LINKFILE)) |
| /* Why LN_LINKFILE does not follow links: |
| * -T/--no-target-directory implies -n/--no-dereference |
| */ |
| ) |
| ) { |
| 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)); |
| 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; |
| } |
| } |
| |
| 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) { |
| unlink(src); |
| } |
| |
| link_func = link; |
| if (opts & LN_SYMLINK) { |
| link_func = symlink; |
| } |
| |
| if (opts & LN_VERBOSE) { |
| printf("'%s' -> '%s'\n", src, *argv); |
| } |
| |
| if (link_func(*argv, src) != 0) { |
| bb_simple_perror_msg(src); |
| status = EXIT_FAILURE; |
| } |
| |
| free(src_name); |
| } while ((++argv)[1]); |
| |
| return status; |
| } |