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ln: Add support for target directories

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Also, now that we are using {sym,}linkat, implement the trivial -L and
-P options.
This commit is contained in:
Michael Forney
2014-11-23 20:25:39 +00:00
committed by sin
parent cb427d553a
commit 94ef670b27
2 changed files with 47 additions and 17 deletions
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11
ln.1
View File

@@ -3,12 +3,12 @@
ln \- make links between files
.SH SYNOPSIS
.B ln
.RB [ \-fs ]
.RB [ \-LPfs ]
.I file
.RI [ name ]
.P
.B ln
.RB [ \-fs ]
.RB [ \-LPfs ]
.RI [ file ...]
.RI [ directory ]
.SH DESCRIPTION
@@ -18,6 +18,13 @@ it is linked into the current directory. If multiple files are listed they will
be linked into the given directory.
.SH OPTIONS
.TP
.B \-L
create links to the files referenced by symbolic link source files (default
behavior).
.TP
.B \-P
create links to symbolic link source files themselves.
.TP
.B \-f
remove existing destinations.
.TP

53
ln.c
View File

@@ -1,9 +1,11 @@
/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <fcntl.h>
#include <libgen.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include "util.h"
@@ -11,16 +13,20 @@
static void
usage(void)
{
eprintf("usage: %s [-fs] target [linkname]\n", argv0);
eprintf("usage: %1$s [-LPfs] target [linkname]\n"
" %1$s [-LPfs] target... directory\n", argv0);
}
int
main(int argc, char *argv[])
{
int (*flink)(const char *, const char *);
char *fname, *to;
int sflag = 0;
int fflag = 0;
int hasto = 0;
int dirfd = AT_FDCWD;
int flags = AT_SYMLINK_FOLLOW;
struct stat st;
ARGBEGIN {
case 'f':
@@ -29,27 +35,44 @@ main(int argc, char *argv[])
case 's':
sflag = 1;
break;
case 'L':
flags |= AT_SYMLINK_FOLLOW;
break;
case 'P':
flags &= ~AT_SYMLINK_FOLLOW;
break;
default:
usage();
} ARGEND;
if (argc == 0 || argc > 2)
if (argc == 0)
usage();
if (sflag) {
flink = symlink;
fname = "symlink";
} else {
flink = link;
fname = "link";
fname = sflag ? "symlink" : "link";
if (argc >= 2) {
if (stat(argv[argc - 1], &st) == 0 && S_ISDIR(st.st_mode)) {
if ((dirfd = open(argv[argc - 1], O_RDONLY)) < 0)
eprintf("open:");
} else if (argc == 2) {
to = argv[1];
hasto = 1;
} else {
eprintf("destination is not a directory\n");
}
argc--;
}
to = argc < 2 ? basename(argv[0]) : argv[1];
if (fflag)
remove(to);
if (flink(argv[0], to) < 0)
eprintf("%s %s <- %s:", fname, argv[0], to);
for (; argc > 0; argc--, argv++) {
if (!hasto)
to = basename(argv[0]);
if (fflag)
remove(to);
if ((!sflag ? linkat(AT_FDCWD, argv[0], dirfd, to, flags)
: symlinkat(argv[0], dirfd, to)) < 0) {
eprintf("%s %s <- %s:", fname, argv[0], to);
}
}
return 0;
}