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/* ln.c - Create filesystem links
*
* Copyright 2012 Andre Renaud <andre@bluewatersys.com>
*
* See http://opengroup.org/onlinepubs/9699919799/utilities/ln.html
USE_LN(NEWTOY(ln, "<1rt:Tvnfs", TOYFLAG_BIN))
config LN
bool "ln"
default y
help
usage: ln [-sfnv] [-t DIR] [FROM...] TO
Create a link between FROM and TO.
One/two/many arguments work like "mv" or "cp".
-s Create a symbolic link
-f Force the creation of the link, even if TO already exists
-n Symlink at TO treated as file
-r Create relative symlink from -> to
-t Create links in DIR
-T TO always treated as file, max 2 arguments
-v Verbose
*/
#define FOR_ln
#include "toys.h"
GLOBALS(
char *t;
)
void ln_main(void)
{
char *dest = TT.t ? TT.t : toys.optargs[--toys.optc], *new;
struct stat buf;
int i, rc;
if (FLAG(T) && toys.optc>1) help_exit("Max 2 arguments");
// With one argument, create link in current directory.
if (!toys.optc) {
toys.optc++;
dest = ".";
}
// Is destination a directory?
if (!((FLAG(n)||FLAG(T)) ? lstat : stat)(dest, &buf)) {
if ((i = S_ISDIR(buf.st_mode)) ? FLAG(T) : (toys.optc>1 || TT.t))
error_exit("'%s' %s a directory", dest, i ? "is" : "not");
} else buf.st_mode = 0;
for (i=0; i<toys.optc; i++) {
char *oldnew = 0, *try = toys.optargs[i];
if (S_ISDIR(buf.st_mode)) new = xmprintf("%s/%s", dest, basename(try));
else new = dest;
if (FLAG(r)) {
try = relative_path(new, try);
if (!try) {
if (new != dest) free(new);
continue;
}
toys.optflags |= FLAG_s;
}
// Force needs to unlink the existing target (if any). Do that by creating
// a temp version and renaming it over the old one, so we can retain the
// old file in cases we can't replace it (such as hardlink between mounts).
oldnew = new;
if (FLAG(f)) {
new = xmprintf("%s_XXXXXX", new);
rc = mkstemp(new);
if (rc >= 0) {
close(rc);
if (unlink(new)) perror_msg("unlink '%s'", new);
}
}
rc = FLAG(s) ? symlink(try, new) : link(try, new);
if (FLAG(f)) {
if (!rc) {
int temp;
rc = rename(new, oldnew);
temp = errno;
if (rc && unlink(new)) perror_msg("unlink '%s'", new);
errno = temp;
}
free(new);
new = oldnew;
}
if (rc) perror_msg("cannot create %s link from '%s' to '%s'",
FLAG(s) ? "symbolic" : "hard", try, new);
else if (FLAG(v)) fprintf(stderr, "'%s' -> '%s'\n", new, try);
if (try != toys.optargs[i]) free(try);
if (new != dest) free(new);
}
}