Forbid basename(3) and dirname(3)

There are at least two interpretations of basename(3),
in addition to both functions being allowed to /both/ return a static
buffer (unsuitable in multi-threaded environments) /and/ raze the input
(which encourages overallocations, at best)

Reviewed-by: John Kennedy <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Ryan Moeller <[email protected]>
Signed-off-by: Ahelenia Ziemiańska <[email protected]>
Closes #12105

2 files changed, 7 insertions, 8 deletions

diff --git a/tests/zfs-tests/tests/functional/ctime/Makefile.am b/tests/zfs-tests/tests/functional/ctime/Makefile.am
index e7479ae81..3174f78c6 100644
--- a/tests/zfs-tests/tests/functional/ctime/Makefile.am
+++ b/tests/zfs-tests/tests/functional/ctime/Makefile.am
@@ -11,3 +11,5 @@ pkgexecdir = $(datadir)/@PACKAGE@/zfs-tests/tests/functional/ctime
 
 pkgexec_PROGRAMS = ctime
 ctime_SOURCES = ctime.c
+
+ctime_LDADD = $(abs_top_builddir)/lib/libzfs_core/libzfs_core.la
diff --git a/tests/zfs-tests/tests/functional/ctime/ctime.c b/tests/zfs-tests/tests/functional/ctime/ctime.c
index d01fa0d4e..2d515d957 100644
--- a/tests/zfs-tests/tests/functional/ctime/ctime.c
+++ b/tests/zfs-tests/tests/functional/ctime/ctime.c
@@ -37,6 +37,7 @@
 #include <utime.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <libzutil.h>
 #include <unistd.h>
 #include <strings.h>
 #include <errno.h>
@@ -149,22 +150,18 @@ static int
 do_link(const char *pfile)
 {
 	int ret = 0;
-	char link_file[BUFSIZ] = { 0 };
-	char pfile_copy[BUFSIZ] = { 0 };
-	char *dname;
+	char link_file[BUFSIZ + 16] = { 0 };
 
 	if (pfile == NULL) {
 		return (-1);
 	}
 
-	strncpy(pfile_copy, pfile, sizeof (pfile_copy)-1);
-	pfile_copy[sizeof (pfile_copy) - 1] = '\0';
 	/*
 	 * Figure out source file directory name, and create
 	 * the link file in the same directory.
 	 */
-	dname = dirname((char *)pfile_copy);
-	(void) snprintf(link_file, BUFSIZ, "%s/%s", dname, "link_file");
+	(void) snprintf(link_file, sizeof (link_file),
+	    "%.*s/%s", (int)zfs_dirnamelen(pfile), pfile, "link_file");
 
 	if (link(pfile, link_file) == -1) {
 		(void) fprintf(stderr, "link(%s, %s) failed with errno %d\n",
@@ -321,7 +318,7 @@ main(int argc, char *argv[])
 	(void) snprintf(tfile, sizeof (tfile), "%s/%s", penv[0], penv[1]);
 
 	/*
-	 * If the test file is exists, remove it first.
+	 * If the test file exists, remove it first.
 	 */
 	if (access(tfile, F_OK) == 0) {
 		(void) unlink(tfile);