tools/testing/selftests/exec/execveat.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2014 Google, Inc.
  *
  * Licensed under the terms of the GNU GPL License version 2
  *
  * Selftests for execveat(2).
  */

 #define _GNU_SOURCE  /* to get O_PATH, AT_EMPTY_PATH */
 #include <sys/sendfile.h>
 #include <sys/stat.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>

 static char longpath[2 * PATH_MAX] = "";
 static char *envp[] = { "IN_TEST=yes", NULL, NULL };
 static char *argv[] = { "execveat", "99", NULL };

 static int execveat_(int fd, const char *path, char **argv, char **envp,
 		     int flags)
 {
 #ifdef __NR_execveat
 	return syscall(__NR_execveat, fd, path, argv, envp, flags);
 #else
 	errno = -ENOSYS;
 	return -1;
 #endif
 }

 #define check_execveat_fail(fd, path, flags, errno)	\
 	_check_execveat_fail(fd, path, flags, errno, #errno)
 static int _check_execveat_fail(int fd, const char *path, int flags,
 				int expected_errno, const char *errno_str)
 {
 	int rc;

 	errno = 0;
 	printf("Check failure of execveat(%d, '%s', %d) with %s... ",
 		fd, path?:"(null)", flags, errno_str);
 	rc = execveat_(fd, path, argv, envp, flags);

 	if (rc > 0) {
 		printf("[FAIL] (unexpected success from execveat(2))\n");
 		return 1;
 	}
 	if (errno != expected_errno) {
 		printf("[FAIL] (expected errno %d (%s) not %d (%s)\n",
 			expected_errno, strerror(expected_errno),
 			errno, strerror(errno));
 		return 1;
 	}
 	printf("[OK]\n");
 	return 0;
 }

 static int check_execveat_invoked_rc(int fd, const char *path, int flags,
 				     int expected_rc)
 {
 	int status;
 	int rc;
 	pid_t child;
 	int pathlen = path ? strlen(path) : 0;

 	if (pathlen > 40)
 		printf("Check success of execveat(%d, '%.20s...%s', %d)... ",
 			fd, path, (path + pathlen - 20), flags);
 	else
 		printf("Check success of execveat(%d, '%s', %d)... ",
 			fd, path?:"(null)", flags);
 	child = fork();
 	if (child < 0) {
 		printf("[FAIL] (fork() failed)\n");
 		return 1;
 	}
 	if (child == 0) {
 		/* Child: do execveat(). */
 		rc = execveat_(fd, path, argv, envp, flags);
 		printf("[FAIL]: execveat() failed, rc=%d errno=%d (%s)\n",
 			rc, errno, strerror(errno));
 		exit(1);  /* should not reach here */
 	}
 	/* Parent: wait for & check child's exit status. */
 	rc = waitpid(child, &status, 0);
 	if (rc != child) {
 		printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc);
 		return 1;
 	}
 	if (!WIFEXITED(status)) {
 		printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n",
 			child, status);
 		return 1;
 	}
 	if (WEXITSTATUS(status) != expected_rc) {
 		printf("[FAIL] (child %d exited with %d not %d)\n",
 			child, WEXITSTATUS(status), expected_rc);
 		return 1;
 	}
 	printf("[OK]\n");
 	return 0;
 }

 static int check_execveat(int fd, const char *path, int flags)
 {
 	return check_execveat_invoked_rc(fd, path, flags, 99);
 }

 static char *concat(const char *left, const char *right)
 {
 	char *result = malloc(strlen(left) + strlen(right) + 1);

 	strcpy(result, left);
 	strcat(result, right);
 	return result;
 }

 static int open_or_die(const char *filename, int flags)
 {
 	int fd = open(filename, flags);

 	if (fd < 0) {
 		printf("Failed to open '%s'; "
 			"check prerequisites are available\n", filename);
 		exit(1);
 	}
 	return fd;
 }

 static void exe_cp(const char *src, const char *dest)
 {
 	int in_fd = open_or_die(src, O_RDONLY);
 	int out_fd = open(dest, O_RDWR|O_CREAT|O_TRUNC, 0755);
 	struct stat info;

 	fstat(in_fd, &info);
 	sendfile(out_fd, in_fd, NULL, info.st_size);
 	close(in_fd);
 	close(out_fd);
 }

 #define XX_DIR_LEN 200
 static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script)
 {
 	int fail = 0;
 	int ii, count, len;
 	char longname[XX_DIR_LEN + 1];
 	int fd;

 	if (*longpath == '\0') {
 		/* Create a filename close to PATH_MAX in length */
 		memset(longname, 'x', XX_DIR_LEN - 1);
 		longname[XX_DIR_LEN - 1] = '/';
 		longname[XX_DIR_LEN] = '\0';
 		count = (PATH_MAX - 3) / XX_DIR_LEN;
 		for (ii = 0; ii < count; ii++) {
 			strcat(longpath, longname);
 			mkdir(longpath, 0755);
 		}
 		len = (PATH_MAX - 3) - (count * XX_DIR_LEN);
 		if (len <= 0)
 			len = 1;
 		memset(longname, 'y', len);
 		longname[len] = '\0';
 		strcat(longpath, longname);
 	}
 	exe_cp(src, longpath);

 	/*
 	 * Execute as a pre-opened file descriptor, which works whether this is
 	 * a script or not (because the interpreter sees a filename like
 	 * "/dev/fd/20").
 	 */
 	fd = open(longpath, O_RDONLY);
 	if (fd > 0) {
 		printf("Invoke copy of '%s' via filename of length %lu:\n",
 			src, strlen(longpath));
 		fail += check_execveat(fd, "", AT_EMPTY_PATH);
 	} else {
 		printf("Failed to open length %lu filename, errno=%d (%s)\n",
 			strlen(longpath), errno, strerror(errno));
 		fail++;
 	}

 	/*
 	 * Execute as a long pathname relative to ".".  If this is a script,
 	 * the interpreter will launch but fail to open the script because its
 	 * name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
 	 */
 	if (is_script)
 		fail += check_execveat_invoked_rc(dot_dfd, longpath, 0, 127);
 	else
 		fail += check_execveat(dot_dfd, longpath, 0);

 	return fail;
 }

 static int run_tests(void)
 {
 	int fail = 0;
 	char *fullname = realpath("execveat", NULL);
 	char *fullname_script = realpath("script", NULL);
 	char *fullname_symlink = concat(fullname, ".symlink");
 	int subdir_dfd = open_or_die("subdir", O_DIRECTORY|O_RDONLY);
 	int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral",
 					       O_DIRECTORY|O_RDONLY);
 	int dot_dfd = open_or_die(".", O_DIRECTORY|O_RDONLY);
 	int dot_dfd_path = open_or_die(".", O_DIRECTORY|O_RDONLY|O_PATH);
 	int dot_dfd_cloexec = open_or_die(".", O_DIRECTORY|O_RDONLY|O_CLOEXEC);
 	int fd = open_or_die("execveat", O_RDONLY);
 	int fd_path = open_or_die("execveat", O_RDONLY|O_PATH);
 	int fd_symlink = open_or_die("execveat.symlink", O_RDONLY);
 	int fd_denatured = open_or_die("execveat.denatured", O_RDONLY);
 	int fd_denatured_path = open_or_die("execveat.denatured",
 					    O_RDONLY|O_PATH);
 	int fd_script = open_or_die("script", O_RDONLY);
 	int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
 	int fd_ephemeral_path = open_or_die("execveat.path.ephemeral",
 					    O_RDONLY|O_PATH);
 	int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
 	int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
 	int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);

 	/* Change file position to confirm it doesn't affect anything */
 	lseek(fd, 10, SEEK_SET);

 	/* Normal executable file: */
 	/*   dfd + path */
 	fail += check_execveat(subdir_dfd, "../execveat", 0);
 	fail += check_execveat(dot_dfd, "execveat", 0);
 	fail += check_execveat(dot_dfd_path, "execveat", 0);
 	/*   absolute path */
 	fail += check_execveat(AT_FDCWD, fullname, 0);
 	/*   absolute path with nonsense dfd */
 	fail += check_execveat(99, fullname, 0);
 	/*   fd + no path */
 	fail += check_execveat(fd, "", AT_EMPTY_PATH);
 	/*   O_CLOEXEC fd + no path */
 	fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
 	/*   O_PATH fd */
 	fail += check_execveat(fd_path, "", AT_EMPTY_PATH);

 	/* Mess with executable file that's already open: */
 	/*   fd + no path to a file that's been renamed */
 	rename("execveat.ephemeral", "execveat.moved");
 	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
 	/*   fd + no path to a file that's been deleted */
 	unlink("execveat.moved"); /* remove the file now fd open */
 	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);

 	/* Mess with executable file that's already open with O_PATH */
 	/*   fd + no path to a file that's been deleted */
 	unlink("execveat.path.ephemeral");
 	fail += check_execveat(fd_ephemeral_path, "", AT_EMPTY_PATH);

 	/* Invalid argument failures */
 	fail += check_execveat_fail(fd, "", 0, ENOENT);
 	fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);

 	/* Symlink to executable file: */
 	/*   dfd + path */
 	fail += check_execveat(dot_dfd, "execveat.symlink", 0);
 	fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
 	/*   absolute path */
 	fail += check_execveat(AT_FDCWD, fullname_symlink, 0);
 	/*   fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */
 	fail += check_execveat(fd_symlink, "", AT_EMPTY_PATH);
 	fail += check_execveat(fd_symlink, "",
 			       AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);

 	/* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
 	/*   dfd + path */
 	fail += check_execveat_fail(dot_dfd, "execveat.symlink",
 				    AT_SYMLINK_NOFOLLOW, ELOOP);
 	fail += check_execveat_fail(dot_dfd_path, "execveat.symlink",
 				    AT_SYMLINK_NOFOLLOW, ELOOP);
 	/*   absolute path */
 	fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
 				    AT_SYMLINK_NOFOLLOW, ELOOP);

 	/* Shell script wrapping executable file: */
 	/*   dfd + path */
 	fail += check_execveat(subdir_dfd, "../script", 0);
 	fail += check_execveat(dot_dfd, "script", 0);
 	fail += check_execveat(dot_dfd_path, "script", 0);
 	/*   absolute path */
 	fail += check_execveat(AT_FDCWD, fullname_script, 0);
 	/*   fd + no path */
 	fail += check_execveat(fd_script, "", AT_EMPTY_PATH);
 	fail += check_execveat(fd_script, "",
 			       AT_EMPTY_PATH|AT_SYMLINK_NOFOLLOW);
 	/*   O_CLOEXEC fd fails for a script (as script file inaccessible) */
 	fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH,
 				    ENOENT);
 	fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);

 	/* Mess with script file that's already open: */
 	/*   fd + no path to a file that's been renamed */
 	rename("script.ephemeral", "script.moved");
 	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
 	/*   fd + no path to a file that's been deleted */
 	unlink("script.moved"); /* remove the file while fd open */
 	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);

 	/* Rename a subdirectory in the path: */
 	rename("subdir.ephemeral", "subdir.moved");
 	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
 	fail += check_execveat(subdir_dfd_ephemeral, "script", 0);
 	/* Remove the subdir and its contents */
 	unlink("subdir.moved/script");
 	unlink("subdir.moved");
 	/* Shell loads via deleted subdir OK because name starts with .. */
 	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
 	fail += check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT);

 	/* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */
 	fail += check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL);
 	/* Invalid path => ENOENT */
 	fail += check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT);
 	fail += check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT);
 	fail += check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT);
 	/* Attempt to execute directory => EACCES */
 	fail += check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES);
 	/* Attempt to execute non-executable => EACCES */
 	fail += check_execveat_fail(dot_dfd, "Makefile", 0, EACCES);
 	fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES);
 	fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH,
 				    EACCES);
 	/* Attempt to execute nonsense FD => EBADF */
 	fail += check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF);
 	fail += check_execveat_fail(99, "execveat", 0, EBADF);
 	/* Attempt to execute relative to non-directory => ENOTDIR */
 	fail += check_execveat_fail(fd, "execveat", 0, ENOTDIR);

 	fail += check_execveat_pathmax(dot_dfd, "execveat", 0);
 	fail += check_execveat_pathmax(dot_dfd, "script", 1);
 	return fail;
 }

 static void prerequisites(void)
 {
 	int fd;
 	const char *script = "#!/bin/sh\nexit $*\n";

 	/* Create ephemeral copies of files */
 	exe_cp("execveat", "execveat.ephemeral");
 	exe_cp("execveat", "execveat.path.ephemeral");
 	exe_cp("script", "script.ephemeral");
 	mkdir("subdir.ephemeral", 0755);

 	fd = open("subdir.ephemeral/script", O_RDWR|O_CREAT|O_TRUNC, 0755);
 	write(fd, script, strlen(script));
 	close(fd);
 }

 int main(int argc, char **argv)
 {
 	int ii;
 	int rc;
 	const char *verbose = getenv("VERBOSE");

 	if (argc >= 2) {
 		/* If we are invoked with an argument, don't run tests. */
 		const char *in_test = getenv("IN_TEST");

 		if (verbose) {
 			printf("  invoked with:");
 			for (ii = 0; ii < argc; ii++)
 				printf(" [%d]='%s'", ii, argv[ii]);
 			printf("\n");
 		}

 		/* Check expected environment transferred. */
 		if (!in_test || strcmp(in_test, "yes") != 0) {
 			printf("[FAIL] (no IN_TEST=yes in env)\n");
 			return 1;
 		}

 		/* Use the final argument as an exit code. */
 		rc = atoi(argv[argc - 1]);
 		fflush(stdout);
 	} else {
 		prerequisites();
 		if (verbose)
 			envp[1] = "VERBOSE=1";
 		rc = run_tests();
 		if (rc > 0)
 			printf("%d tests failed\n", rc);
 	}
 	return rc;
 }
	/*
	* Copyright (c) 2014 Google, Inc.
	*
	* Licensed under the terms of the GNU GPL License version 2
	*
	* Selftests for execveat(2).
	*/

	#define _GNU_SOURCE /* to get O_PATH, AT_EMPTY_PATH */
	#include <sys/sendfile.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <sys/types.h>
	#include <sys/wait.h>
	#include <errno.h>
	#include <fcntl.h>
	#include <limits.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <unistd.h>

	static char longpath[2 * PATH_MAX] = "";
	static char *envp[] = { "IN_TEST=yes", NULL, NULL };
	static char *argv[] = { "execveat", "99", NULL };

	static int execveat_(int fd, const char path, char argv, char *envp,
	int flags)
	{
	#ifdef __NR_execveat
	return syscall(__NR_execveat, fd, path, argv, envp, flags);
	#else
	errno = -ENOSYS;
	return -1;
	#endif
	}

	#define check_execveat_fail(fd, path, flags, errno) \
	_check_execveat_fail(fd, path, flags, errno, #errno)
	static int _check_execveat_fail(int fd, const char *path, int flags,
	int expected_errno, const char *errno_str)
	{
	int rc;

	errno = 0;
	printf("Check failure of execveat(%d, '%s', %d) with %s... ",
	fd, path?:"(null)", flags, errno_str);
	rc = execveat_(fd, path, argv, envp, flags);

	if (rc > 0) {
	printf("[FAIL] (unexpected success from execveat(2))\n");
	return 1;
	}
	if (errno != expected_errno) {
	printf("[FAIL] (expected errno %d (%s) not %d (%s)\n",
	expected_errno, strerror(expected_errno),
	errno, strerror(errno));
	return 1;
	}
	printf("[OK]\n");
	return 0;
	}

	static int check_execveat_invoked_rc(int fd, const char *path, int flags,
	int expected_rc)
	{
	int status;
	int rc;
	pid_t child;
	int pathlen = path ? strlen(path) : 0;

	if (pathlen > 40)
	printf("Check success of execveat(%d, '%.20s...%s', %d)... ",
	fd, path, (path + pathlen - 20), flags);
	else
	printf("Check success of execveat(%d, '%s', %d)... ",
	fd, path?:"(null)", flags);
	child = fork();
	if (child < 0) {
	printf("[FAIL] (fork() failed)\n");
	return 1;
	}
	if (child == 0) {
	/* Child: do execveat(). */
	rc = execveat_(fd, path, argv, envp, flags);
	printf("[FAIL]: execveat() failed, rc=%d errno=%d (%s)\n",
	rc, errno, strerror(errno));
	exit(1); /* should not reach here */
	}
	/* Parent: wait for & check child's exit status. */
	rc = waitpid(child, &status, 0);
	if (rc != child) {
	printf("[FAIL] (waitpid(%d,...) returned %d)\n", child, rc);
	return 1;
	}
	if (!WIFEXITED(status)) {
	printf("[FAIL] (child %d did not exit cleanly, status=%08x)\n",
	child, status);
	return 1;
	}
	if (WEXITSTATUS(status) != expected_rc) {
	printf("[FAIL] (child %d exited with %d not %d)\n",
	child, WEXITSTATUS(status), expected_rc);
	return 1;
	}
	printf("[OK]\n");
	return 0;
	}

	static int check_execveat(int fd, const char *path, int flags)
	{
	return check_execveat_invoked_rc(fd, path, flags, 99);
	}

	static char concat(const char left, const char *right)
	{
	char *result = malloc(strlen(left) + strlen(right) + 1);

	strcpy(result, left);
	strcat(result, right);
	return result;
	}

	static int open_or_die(const char *filename, int flags)
	{
	int fd = open(filename, flags);

	if (fd < 0) {
	printf("Failed to open '%s'; "
	"check prerequisites are available\n", filename);
	exit(1);
	}
	return fd;
	}

	static void exe_cp(const char src, const char dest)
	{
	int in_fd = open_or_die(src, O_RDONLY);
	int out_fd = open(dest, O_RDWR\|O_CREAT\|O_TRUNC, 0755);
	struct stat info;

	fstat(in_fd, &info);
	sendfile(out_fd, in_fd, NULL, info.st_size);
	close(in_fd);
	close(out_fd);
	}

	#define XX_DIR_LEN 200
	static int check_execveat_pathmax(int dot_dfd, const char *src, int is_script)
	{
	int fail = 0;
	int ii, count, len;
	char longname[XX_DIR_LEN + 1];
	int fd;

	if (*longpath == '\0') {
	/* Create a filename close to PATH_MAX in length */
	memset(longname, 'x', XX_DIR_LEN - 1);
	longname[XX_DIR_LEN - 1] = '/';
	longname[XX_DIR_LEN] = '\0';
	count = (PATH_MAX - 3) / XX_DIR_LEN;
	for (ii = 0; ii < count; ii++) {
	strcat(longpath, longname);
	mkdir(longpath, 0755);
	}
	len = (PATH_MAX - 3) - (count * XX_DIR_LEN);
	if (len <= 0)
	len = 1;
	memset(longname, 'y', len);
	longname[len] = '\0';
	strcat(longpath, longname);
	}
	exe_cp(src, longpath);

	/*
	* Execute as a pre-opened file descriptor, which works whether this is
	* a script or not (because the interpreter sees a filename like
	* "/dev/fd/20").
	*/
	fd = open(longpath, O_RDONLY);
	if (fd > 0) {
	printf("Invoke copy of '%s' via filename of length %lu:\n",
	src, strlen(longpath));
	fail += check_execveat(fd, "", AT_EMPTY_PATH);
	} else {
	printf("Failed to open length %lu filename, errno=%d (%s)\n",
	strlen(longpath), errno, strerror(errno));
	fail++;
	}

	/*
	* Execute as a long pathname relative to ".". If this is a script,
	* the interpreter will launch but fail to open the script because its
	* name ("/dev/fd/5/xxx....") is bigger than PATH_MAX.
	*/
	if (is_script)
	fail += check_execveat_invoked_rc(dot_dfd, longpath, 0, 127);
	else
	fail += check_execveat(dot_dfd, longpath, 0);

	return fail;
	}

	static int run_tests(void)
	{
	int fail = 0;
	char *fullname = realpath("execveat", NULL);
	char *fullname_script = realpath("script", NULL);
	char *fullname_symlink = concat(fullname, ".symlink");
	int subdir_dfd = open_or_die("subdir", O_DIRECTORY\|O_RDONLY);
	int subdir_dfd_ephemeral = open_or_die("subdir.ephemeral",
	O_DIRECTORY\|O_RDONLY);
	int dot_dfd = open_or_die(".", O_DIRECTORY\|O_RDONLY);
	int dot_dfd_path = open_or_die(".", O_DIRECTORY\|O_RDONLY\|O_PATH);
	int dot_dfd_cloexec = open_or_die(".", O_DIRECTORY\|O_RDONLY\|O_CLOEXEC);
	int fd = open_or_die("execveat", O_RDONLY);
	int fd_path = open_or_die("execveat", O_RDONLY\|O_PATH);
	int fd_symlink = open_or_die("execveat.symlink", O_RDONLY);
	int fd_denatured = open_or_die("execveat.denatured", O_RDONLY);
	int fd_denatured_path = open_or_die("execveat.denatured",
	O_RDONLY\|O_PATH);
	int fd_script = open_or_die("script", O_RDONLY);
	int fd_ephemeral = open_or_die("execveat.ephemeral", O_RDONLY);
	int fd_ephemeral_path = open_or_die("execveat.path.ephemeral",
	O_RDONLY\|O_PATH);
	int fd_script_ephemeral = open_or_die("script.ephemeral", O_RDONLY);
	int fd_cloexec = open_or_die("execveat", O_RDONLY\|O_CLOEXEC);
	int fd_script_cloexec = open_or_die("script", O_RDONLY\|O_CLOEXEC);

	/* Change file position to confirm it doesn't affect anything */
	lseek(fd, 10, SEEK_SET);

	/* Normal executable file: */
	/* dfd + path */
	fail += check_execveat(subdir_dfd, "../execveat", 0);
	fail += check_execveat(dot_dfd, "execveat", 0);
	fail += check_execveat(dot_dfd_path, "execveat", 0);
	/* absolute path */
	fail += check_execveat(AT_FDCWD, fullname, 0);
	/* absolute path with nonsense dfd */
	fail += check_execveat(99, fullname, 0);
	/* fd + no path */
	fail += check_execveat(fd, "", AT_EMPTY_PATH);
	/* O_CLOEXEC fd + no path */
	fail += check_execveat(fd_cloexec, "", AT_EMPTY_PATH);
	/* O_PATH fd */
	fail += check_execveat(fd_path, "", AT_EMPTY_PATH);

	/* Mess with executable file that's already open: */
	/* fd + no path to a file that's been renamed */
	rename("execveat.ephemeral", "execveat.moved");
	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);
	/* fd + no path to a file that's been deleted */
	unlink("execveat.moved"); /* remove the file now fd open */
	fail += check_execveat(fd_ephemeral, "", AT_EMPTY_PATH);

	/* Mess with executable file that's already open with O_PATH */
	/* fd + no path to a file that's been deleted */
	unlink("execveat.path.ephemeral");
	fail += check_execveat(fd_ephemeral_path, "", AT_EMPTY_PATH);

	/* Invalid argument failures */
	fail += check_execveat_fail(fd, "", 0, ENOENT);
	fail += check_execveat_fail(fd, NULL, AT_EMPTY_PATH, EFAULT);

	/* Symlink to executable file: */
	/* dfd + path */
	fail += check_execveat(dot_dfd, "execveat.symlink", 0);
	fail += check_execveat(dot_dfd_path, "execveat.symlink", 0);
	/* absolute path */
	fail += check_execveat(AT_FDCWD, fullname_symlink, 0);
	/* fd + no path, even with AT_SYMLINK_NOFOLLOW (already followed) */
	fail += check_execveat(fd_symlink, "", AT_EMPTY_PATH);
	fail += check_execveat(fd_symlink, "",
	AT_EMPTY_PATH\|AT_SYMLINK_NOFOLLOW);

	/* Symlink fails when AT_SYMLINK_NOFOLLOW set: */
	/* dfd + path */
	fail += check_execveat_fail(dot_dfd, "execveat.symlink",
	AT_SYMLINK_NOFOLLOW, ELOOP);
	fail += check_execveat_fail(dot_dfd_path, "execveat.symlink",
	AT_SYMLINK_NOFOLLOW, ELOOP);
	/* absolute path */
	fail += check_execveat_fail(AT_FDCWD, fullname_symlink,
	AT_SYMLINK_NOFOLLOW, ELOOP);

	/* Shell script wrapping executable file: */
	/* dfd + path */
	fail += check_execveat(subdir_dfd, "../script", 0);
	fail += check_execveat(dot_dfd, "script", 0);
	fail += check_execveat(dot_dfd_path, "script", 0);
	/* absolute path */
	fail += check_execveat(AT_FDCWD, fullname_script, 0);
	/* fd + no path */
	fail += check_execveat(fd_script, "", AT_EMPTY_PATH);
	fail += check_execveat(fd_script, "",
	AT_EMPTY_PATH\|AT_SYMLINK_NOFOLLOW);
	/* O_CLOEXEC fd fails for a script (as script file inaccessible) */
	fail += check_execveat_fail(fd_script_cloexec, "", AT_EMPTY_PATH,
	ENOENT);
	fail += check_execveat_fail(dot_dfd_cloexec, "script", 0, ENOENT);

	/* Mess with script file that's already open: */
	/* fd + no path to a file that's been renamed */
	rename("script.ephemeral", "script.moved");
	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);
	/* fd + no path to a file that's been deleted */
	unlink("script.moved"); /* remove the file while fd open */
	fail += check_execveat(fd_script_ephemeral, "", AT_EMPTY_PATH);

	/* Rename a subdirectory in the path: */
	rename("subdir.ephemeral", "subdir.moved");
	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
	fail += check_execveat(subdir_dfd_ephemeral, "script", 0);
	/* Remove the subdir and its contents */
	unlink("subdir.moved/script");
	unlink("subdir.moved");
	/* Shell loads via deleted subdir OK because name starts with .. */
	fail += check_execveat(subdir_dfd_ephemeral, "../script", 0);
	fail += check_execveat_fail(subdir_dfd_ephemeral, "script", 0, ENOENT);

	/* Flag values other than AT_SYMLINK_NOFOLLOW => EINVAL */
	fail += check_execveat_fail(dot_dfd, "execveat", 0xFFFF, EINVAL);
	/* Invalid path => ENOENT */
	fail += check_execveat_fail(dot_dfd, "no-such-file", 0, ENOENT);
	fail += check_execveat_fail(dot_dfd_path, "no-such-file", 0, ENOENT);
	fail += check_execveat_fail(AT_FDCWD, "no-such-file", 0, ENOENT);
	/* Attempt to execute directory => EACCES */
	fail += check_execveat_fail(dot_dfd, "", AT_EMPTY_PATH, EACCES);
	/* Attempt to execute non-executable => EACCES */
	fail += check_execveat_fail(dot_dfd, "Makefile", 0, EACCES);
	fail += check_execveat_fail(fd_denatured, "", AT_EMPTY_PATH, EACCES);
	fail += check_execveat_fail(fd_denatured_path, "", AT_EMPTY_PATH,
	EACCES);
	/* Attempt to execute nonsense FD => EBADF */
	fail += check_execveat_fail(99, "", AT_EMPTY_PATH, EBADF);
	fail += check_execveat_fail(99, "execveat", 0, EBADF);
	/* Attempt to execute relative to non-directory => ENOTDIR */
	fail += check_execveat_fail(fd, "execveat", 0, ENOTDIR);

	fail += check_execveat_pathmax(dot_dfd, "execveat", 0);
	fail += check_execveat_pathmax(dot_dfd, "script", 1);
	return fail;
	}

	static void prerequisites(void)
	{
	int fd;
	const char script = "#!/bin/sh\nexit $\n";

	/* Create ephemeral copies of files */
	exe_cp("execveat", "execveat.ephemeral");
	exe_cp("execveat", "execveat.path.ephemeral");
	exe_cp("script", "script.ephemeral");
	mkdir("subdir.ephemeral", 0755);

	fd = open("subdir.ephemeral/script", O_RDWR\|O_CREAT\|O_TRUNC, 0755);
	write(fd, script, strlen(script));
	close(fd);
	}

	int main(int argc, char **argv)
	{
	int ii;
	int rc;
	const char *verbose = getenv("VERBOSE");

	if (argc >= 2) {
	/* If we are invoked with an argument, don't run tests. */
	const char *in_test = getenv("IN_TEST");

	if (verbose) {
	printf(" invoked with:");
	for (ii = 0; ii < argc; ii++)
	printf(" [%d]='%s'", ii, argv[ii]);
	printf("\n");
	}

	/* Check expected environment transferred. */
	if (!in_test \|\| strcmp(in_test, "yes") != 0) {
	printf("[FAIL] (no IN_TEST=yes in env)\n");
	return 1;
	}

	/* Use the final argument as an exit code. */
	rc = atoi(argv[argc - 1]);
	fflush(stdout);
	} else {
	prerequisites();
	if (verbose)
	envp[1] = "VERBOSE=1";
	rc = run_tests();
	if (rc > 0)
	printf("%d tests failed\n", rc);
	}
	return rc;
	}