nftw miscalculates FTW.base when pathnames end in /

[Joakim Sindholt <opensource@zhasha.com>]

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Running the test program from the glibc ftw man page[1]:

+zhasha@wirbelwind /home/zhasha ; ./6.out test
d    0    4096   test                                     0 test
d    1    4096   test/a                                   5 a
f    2       0   test/a/1                                 7 1
d    1    4096   test/b                                   5 b
f    2       0   test/b/1                                 7 1
f    2       0   test/b/2                                 7 2
d    1    4096   test/ddd                                 5 ddd
f    2       0   test/ddd/5                               9 5
d    1    4096   test/cc                                  5 cc
f    2       0   test/cc/3                                8 3
+zhasha@wirbelwind /home/zhasha ; ./6.out test/
d    0    4096   test/                                    4 /
d    1    4096   test/a                                   6
f    2       0   test/a/1                                 7 1
d    1    4096   test/b                                   6
f    2       0   test/b/1                                 7 1
f    2       0   test/b/2                                 7 2
d    1    4096   test/ddd                                 6 dd
f    2       0   test/ddd/5                               9 5
d    1    4096   test/cc                                  6 c
f    2       0   test/cc/3                                8 3

The final 2 columns are the file name length and path + ftw->base
respectively, which is off by one when the path ends in /. It also
seems to confuse the initial dir name.

I have attached a fix but I'm not sure it's a particularly good one.

[1] http://linux.die.net/man/3/ftw

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diff --git a/src/misc/nftw.c b/src/misc/nftw.c
index efb2b89..7c2c0d3 100644
--- a/src/misc/nftw.c
+++ b/src/misc/nftw.c
@@ -108,11 +108,13 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
 	if (fd_limit <= 0) return 0;
 
 	l = strlen(path);
+	while (l && path[l-1]=='/') --l;
 	if (l > PATH_MAX) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
-	memcpy(pathbuf, path, l+1);
+	memcpy(pathbuf, path, l);
+	pathbuf[l]='\0';
 	
 	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 	r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);