From e0cbe4863704c78ea703c06c0dd2d76ebac90f75 Mon Sep 17 00:00:00 2001
From: Eric Andersen
Date: Thu, 19 Feb 2004 00:44:08 +0000
Subject: Chris Larson (kergoth) writes:

I was adding -s/--symbolic-link support to busybox cp when I noticed a
bug with -r/-a.  Test case:

mkdir -p test/out
cd test
busybox cp -a * out/

Will never return until we run out of open files or similar.
Coreutils cp on the other hand will error with "cannot copy a directory,
`out', into itself, `out'".  Patch attached.
---
 libbb/copy_file.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/libbb/copy_file.c b/libbb/copy_file.c
index 7ddb9a2..637b817 100644
--- a/libbb/copy_file.c
+++ b/libbb/copy_file.c
@@ -65,12 +65,28 @@ int copy_file(const char *source, const char *dest, int flags)
 		DIR *dp;
 		struct dirent *d;
 		mode_t saved_umask = 0;
+		char *dstparent;
+		struct stat dstparent_stat;
 
 		if (!(flags & FILEUTILS_RECUR)) {
 			bb_error_msg("%s: omitting directory", source);
 			return -1;
 		}
 
+		dstparent = dirname(bb_xstrdup(dest));
+		if (lstat(dstparent, &dstparent_stat) < 0) {
+			bb_perror_msg("unable to stat `%s'", dstparent);
+			free(dstparent);
+			return -1;
+		}
+		free(dstparent);
+
+		if (source_stat.st_dev == dstparent_stat.st_dev &&
+			source_stat.st_ino == dstparent_stat.st_ino) {
+			bb_error_msg("cannot copy a directory, `%s', into itself, `%s'", source, dest);
+			return -1;
+		}
+
 		/* Create DEST.  */
 		if (dest_exists) {
 			if (!S_ISDIR(dest_stat.st_mode)) {
-- 
cgit v1.1