1 /* ln.c - Create filesystem links
2 *
3 * Copyright 2012 Andre Renaud <andre@bluewatersys.com>
4 *
5 * See http://opengroup.org/onlinepubs/9699919799/utilities/ln.html
6
7 USE_LN(NEWTOY(ln, "<1t:Tvnfs", TOYFLAG_BIN))
8
9 config LN
10 bool "ln"
11 default y
12 help
13 usage: ln [-sfnv] [-t DIR] [FROM...] TO
14
15 Create a link between FROM and TO.
16 One/two/many arguments work like "mv" or "cp".
17
18 -s Create a symbolic link
19 -f Force the creation of the link, even if TO already exists
20 -n Symlink at TO treated as file
21 -t Create links in DIR
22 -T TO always treated as file, max 2 arguments
23 -v Verbose
24 */
25
26 #define FOR_ln
27 #include "toys.h"
28
GLOBALS(char * t;)29 GLOBALS(
30 char *t;
31 )
32
33 void ln_main(void)
34 {
35 char *dest = TT.t ? TT.t : toys.optargs[--toys.optc], *new;
36 struct stat buf;
37 int i;
38
39 // With one argument, create link in current directory.
40 if (!toys.optc) {
41 toys.optc++;
42 dest=".";
43 }
44
45 if (FLAG(T) && toys.optc>1) help_exit("Max 2 arguments");
46 // Is destination a directory?
47 if (!((FLAG(n)||FLAG(T)) ? lstat : stat)(dest, &buf)) {
48 i = S_ISDIR(buf.st_mode);
49
50 if ((FLAG(T) && i) || (!i && (toys.optc>1 || TT.t)))
51 error_exit("'%s' %s a directory", dest, i ? "is" : "not");
52 } else buf.st_mode = 0;
53
54 for (i=0; i<toys.optc; i++) {
55 int rc;
56 char *oldnew, *try = toys.optargs[i];
57
58 if (S_ISDIR(buf.st_mode)) new = xmprintf("%s/%s", dest, basename(try));
59 else new = dest;
60
61 // Force needs to unlink the existing target (if any). Do that by creating
62 // a temp version and renaming it over the old one, so we can retain the
63 // old file in cases we can't replace it (such as hardlink between mounts).
64 oldnew = new;
65 if (FLAG(f)) {
66 new = xmprintf("%s_XXXXXX", new);
67 rc = mkstemp(new);
68 if (rc >= 0) {
69 close(rc);
70 if (unlink(new)) perror_msg("unlink '%s'", new);
71 }
72 }
73
74 rc = FLAG(s) ? symlink(try, new) : link(try, new);
75 if (FLAG(f)) {
76 if (!rc) {
77 int temp;
78
79 rc = rename(new, oldnew);
80 temp = errno;
81 if (rc && unlink(new)) perror_msg("unlink '%s'", new);
82 errno = temp;
83 }
84 free(new);
85 new = oldnew;
86 }
87 if (rc) perror_msg("cannot create %s link from '%s' to '%s'",
88 FLAG(s) ? "symbolic" : "hard", try, new);
89 else if (FLAG(v)) fprintf(stderr, "'%s' -> '%s'\n", new, try);
90
91 if (new != dest) free(new);
92 }
93 }
94