This is xnu-6153.11.26. See this file in:
#include <darwintest.h>

#include "xnu_quick_test_helpers.h"

#include <fcntl.h>
#include <unistd.h>

void
create_target_directory( const char * the_targetp )
{
	int             err;
	const char *    my_targetp;

	my_targetp = getenv("TMPDIR");
	if (my_targetp == NULL) {
		my_targetp = "/tmp";
	}

	T_ASSERT_LT( strlen( the_targetp ), (unsigned long)(PATH_MAX - 1),
	    "check target path too long - \"%s\"", the_targetp );

	for (;;) {
		int         my_rand;
		char        my_name[64];

		my_rand = rand();
		sprintf( &my_name[0], "xnu_quick_test-%d", my_rand );
		T_ASSERT_LT( strlen( &my_name[0] ) + strlen( the_targetp ) + 2, (unsigned long)PATH_MAX,
		    "check target path plus our test directory name is too long: "
		    "target path - \"%s\" test directory name - \"%s\"",
		    the_targetp, &my_name[0] );

		/* append generated directory name onto our path */
		g_target_path[0] = 0x00;
		strcat( &g_target_path[0], the_targetp );
		if (g_target_path[(strlen(the_targetp) - 1)] != '/') {
			strcat( &g_target_path[0], "/" );
		}
		strcat( &g_target_path[0], &my_name[0] );

		/* try to create the test directory */
		err = mkdir( &g_target_path[0], (S_IRWXU | S_IRWXG | S_IROTH));
		if (err == 0) {
			break;
		}
		err = errno;
		if (EEXIST != err) {
			T_ASSERT_FAIL( "test directory creation failed - \"%s\" \n"
			    "mkdir call failed with error %d - \"%s\"",
			    &g_target_path[0], errno, strerror( err));
		}
	}
} /* create_target_directory */

/*
 * create_random_name - creates a file with a random / unique name in the given directory.
 * when do_open is true we create a file else we generaate a name that does not exist in the
 * given directory (we do not create anything when do_open is 0).
 * WARNING - caller provides enough space in path buffer for longest possible name.
 * WARNING - assumes caller has appended a trailing '/' on the path passed to us.
 * RAND_MAX is currently 2147483647 (ten characters plus one for a slash)
 */
int
create_random_name( char *the_pathp, int do_open )
{
	int     i, my_err;
	int     my_fd = -1;

	for (i = 0; i < 1; i++) {
		int         my_rand;
		char        *myp;
		char        my_name[32];

		my_rand = rand();
		sprintf( &my_name[0], "%d", my_rand );
		T_ASSERT_LT_ULONG((strlen( &my_name[0] ) + strlen( the_pathp ) + 2), (unsigned long)PATH_MAX,
		    "check if path to test file is less than PATH_MAX");

		// append generated file name onto our path
		myp = strrchr( the_pathp, '/' );
		*(myp + 1) = 0x00;
		strcat( the_pathp, &my_name[0] );
		if (do_open) {
			/* create a file with this name */
			my_fd = open( the_pathp, (O_RDWR | O_CREAT | O_EXCL),
			    (S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH));
			T_EXPECT_TRUE((my_fd != -1 || errno == EEXIST), "open file with name %s", the_pathp);

			if (errno == EEXIST) {
				continue;
			}
		} else {
			/* make sure the name is unique */
			struct stat     my_sb;
			my_err = stat( the_pathp, &my_sb );
			T_EXPECT_TRUE((my_err == 0 || errno == ENOENT), "make sure the name is unique");

			if (errno == ENOENT) {
				break;
			}
			/* name already exists, try another */
			i--;
			continue;
		}
	}

	if (my_fd != -1) {
		close( my_fd );
	}

	if (do_open && my_fd == -1) {
		return 1;
	}

	return 0;
} /* create_random_name */

void
remove_target_directory()
{
	rmdir(&g_target_path[0]);
}